Earlier this week, I took my daughter over to Catalina Island to dive at Casino Point, the popular underwater park established in 1962. It is also a no-take State Marine Conservation Area, one of California’s 124 marine protected areas. Fishing and nearly every other kind of “take” are prohibited. The visibility was great, maybe 60 feet, and the number and variety of fish we saw were impressive. The only downside is that we did not see a giant black sea bass.

But to me, the dive was a reminder of the steps California has taken to improve its marine ecosystems, and of how protection, as well as patience, can make a real difference. So I thought I’d take a quick look at how we got here and where we might be going, because the state is reviewing the network right now and considering changes that could expand some protected areas while shrinking or weakening others.

Twenty-some years ago, California tried something no one in the US had really done before: instead of scattering a few marine reserves along the coast and hoping for the best, it set out to build a connected network of underwater parks, designed by scientists and experienced water users with a personal stake in the ocean. The latter meant not only surfers, but also commercial and recreational fishermen, divers, and tribal communities. Oh, and there would be enforcement.

The idea came out of the Marine Life Protection Act, passed in 1999 at a low moment for the coast. Rockfish populations had severely declined. Abalone had been so overfished that it was literally impossible to find the delicious and popular gastropods. The state’s existing patchwork of protected areas was, in the law’s own assessment, created “piecemeal,” too small and scattered to be effective. The first two attempts at implementing the law failed. What finally worked was a slow, regional process that brought together interested parties who hashed out maps region by region. And it took nearly a decade. When the final piece snapped into place on the North Coast in December 2012, California had 124 marine protected areas covering about 16 percent of state waters (although only 9.4 percent was fully no-take), the largest scientifically designed MPA network in the world.

The bet was that protection, given time, would pay off. It has. In other words, we seemed to learn an obvious lesson: if you leave nature alone, it often recovers.

When the state completed its first decadal review of the network in 2023, the signal was clear: inside the MPAs, there are more fish, and they are bigger, particularly the species that fishing targets most, like kelp bass, lingcod, and rockfish.

We wrote about the astonishing recovery of rockfish a while back: by late 2025, many West Coast groundfish stocks previously classified as overfished had been declared rebuilt.

In recent years, I have also noticed more fish on my dives and heard similar observations from fishermen. That is anecdotal, of course, but it is consistent with growing evidence that California’s marine protected areas are helping fish populations recover.

On a recent boat trip to the Channel Islands, I spoke with Molly Morse, a biologist with the Benioff Ocean Science Laboratory at UC Santa Barbara. She explained why allowing fish to grow larger inside these reserves can benefit the surrounding ecosystem and even nearby fisheries.

“The marine protected areas are really a special place for allowing fish to grow,” she told me. “And when the fish get larger, they’re able to reproduce and produce a lot more offspring. So we get higher returns from bigger fish. So that means we have larger spillover.”

Oh, and by the way, the stakes go beyond fish. After the 2014–2016 marine heatwave, kelp forests inside Southern California’s fully protected reserves recovered faster and more strongly than those in unprotected waters, suggesting MPAs can also help broader ecosystems withstand a warming ocean.

Here’s why this all matters now: the network’s future is being decided as I write this. California officials are considering 15 proposals that could expand, shrink, or otherwise change protected areas along the coast, with the Fish and Game Commission expected to take them up in October 2026.

What’s important is that we now have many of these reserves for a relatively significant amount of time. It’s still nowhere near where we should be, but we’re finally beginning to see what long-term protection can accomplish. The Channel Islands marine reserves, established in 2003, are now 23 years old and have shown impressive gains in the number, biomass, and size of targeted fish within their boundaries.

A reserve doesn’t reveal what it’s doing in five years. It reveals it in twenty.

“It really takes time for these places to have an impact,” said Morse. “But we’ve already been seeing that effect. Scuba diving companies seek out these locations because their clients want to come see the large fish, the giant sea bass, that live here. Also things like recreational lobster fishing.”

What’s also key is the spillover effect that Morse mentions above: At the Channel Islands, spiny lobsters inside the MPAs have grown so large and abundant that they migrate into surrounding waters, where the lobster fishery has benefited.

The same spillover effect has also been documented along the Central Coast among fish living in and around other marine reserves.

I find the bigger picture here genuinely encouraging, and I don’t say that often about ocean news. We tend to talk about conservation as sacrifice and what we give up. California’s MPAs are a two-decade experiment showing that we get something back. They’ve become a model studied around the world, and the blueprint for the “30x30” targets now written into both state and international policy. None of it required new technology or a miracle. It required commitment and patience. AND the political will to leave some places alone for a while.

The ocean knows how to heal itself, assuming things don’t get so hot and miserable that the whole system comes tumbling down, an outcome that seems tragically more possible every day. But we’re not there yet, and I still have hope that, over time, we can make the right decisions. The key point is that we now have hard scientific evidence that these protections work.

And it’s happening right here in California.

Behind a nondescript door in the Bioscience Building at Occidental College is one of the more remarkable scientific collections in Los Angeles. The room, tucked beside the laboratory of biology professor Joseph Schulz, contains cabinet after cabinet filled with seashells. Schulz is the curator of the collection. There are nearly 117,000 specimens in all, collected from the Caribbean, Hawaii, the Gulf of Mexico, the Indo-Pacific and other waters around the world.

I first became intrigued by the Cosman Collection several years ago, after reading about it online, and reached out to Schultz to see if we could arrange a visit. He graciously offered up a date, and so last week I was joined by my California Curated colleague Tod Mesirow and my son Finn. I came away impressed not only by the astonishing variety of shells in the collection, but also by the fascinating research Schulz and his students are conducting in the lab next door.

The collection was assembled by Dieter Cosman, a Swiss-born businessman who spent nearly 50 years diving, dredging and searching the seafloor, sometimes even in a submersible, looking for rare and unusual seashells. Cosman was not a professional scientist. He ran a Florida yacht business. But he approached shell collecting with unusual discipline and tenacity, recording where, when, and sometimes at what depth each specimen was found. That information can be of immense benefit to scientists trying to understand how the world is changing.

“Dieter Cosman had a love for malacology and for finding different types of snail and bivalve species from all over the world,” says Schultz.

When Cosman died in 2012 at the age of 95, his family wanted the collection to remain intact. His oldest son, Ed, had graduated from Occidental, and the family donated the shells to the college in 2014.

Occidental is a small liberal arts college set among the hills of Eagle Rock in northeast Los Angeles. It is not widely known outside California, although Barack Obama attended for two years, from 1979 to 1981, before transferring to Columbia University. The college also has some remarkable scientific departments, particularly in biology, marine science, and natural-history research.

The Cosman collection is not really presented like a museum exhibit (although there is also a small display of some extraordinary-looking shells in the lobby). You enter through the door, and there are tall shelves of shells of various shapes and sizes. This is a bit of an understatement. Some of the shells are really weird. And although it is an official scientific collection, the place is still kind of a working archive. Open one of the vintage slide-out scientific cabinets, and you find drawer after drawer of shells in plastic bags and small containers, many accompanied by Cosman’s original labels. Cosman was analogue.

“In fact, the entire catalog came on a series of very large Rolodexes,” Schultz told me.

Some shells are large and spectacular. Others are so small you can only see them under a dissecting microscope. Cosman became increasingly interested in these so-called micromollusks later in life, apparently fascinated by their diversity. He dredged sand from the seafloor and searched through it for shells no larger than a grain of sand.

There are shells everywhere. Large, creamy-looking conches and spiny oysters sit on shelves. The latter resemble tiny explosions of calcium carbonate, the mineral from which shells are largely made. Other specimens are scattered around Schulz’s office, alongside books, scientific equipment, and sitting in tiny specimen bags.

The real value of the collection is not simply the shells. It is the information Cosman preserved with them.

“In addition to the specimens in the collection, we have a lot of detailed information about where and when the specimens were collected,” says Schulz. “That gives us a very detailed view of how these animals live and where they live on the planet.”

Because he returned to some locations repeatedly, the collection contains snapshots of marine communities taken years or even decades apart. Researchers can return to those places and ask whether the same species still live there, whether their shells have changed, or whether warming, pollution, fishing, and development have altered the ecosystem.

And sometimes the shells contain another kind of information.

Cosman generally cleaned them by hand instead of bleaching them. As a result, some still retain bits of dried tissue, including the periostracum, the thin organic coating on the outside of a shell. It’s like a skin, and I did not know it even existed. Schulz and his students have been able to extract DNA from that material and do some remarkable things with it.

“We’ve been able to isolate DNA from specimens in the Cosman Shell Collection, and obtain novel neurotoxin-encoding sequences, synthesize those novel neurotoxins and test them in the lab on neurons,” Schulz says.

That could help scientists understand how nervous systems work and potentially identify compounds with medical uses. Such compounds can become valuable tools for understanding the nervous system and, in rare cases, lead to new medicines.

The best-known example is ziconotide, sold as Prialt, a powerful non-opioid pain medication based on a toxin produced by the Magician’s cone snail (Conus magus). It remains the only cone-snail-derived peptide approved as a drug, but researchers continue to investigate others for possible applications involving pain, epilepsy, and neurological disease.

This brings the collection directly into Schulz’s own research.

In his laboratory, an aquarium holds a living Conus catus, or cat cone, a fish-hunting cone snail that uses venom to subdue its prey, including fish. For the record, I had no idea that snails hunted fish. But they do. Even in his lab.

From a small table, Schulz picked up the shell of a geography cone, Conus geographus. It’s a genuine work of art, resembling an ancient map (hence, its name), or like mountains in a Chinese scroll, as Schulz himself describes it. It also happens to be the deadliest cone snail in the world. With a tiny barbed spear that it can fire at prey or unsuspecting humans, it delivers a potentially fatal dose of venom that will make you stop breathing within minutes. Kids: don’t mess around with cone snails.

Cone snails attack with a hollow, barbed tooth that functions like a microscopic hypodermic needle. Schulz helped discover exactly how the weapon works. Using high-speed video and microscopic examination, he and his collaborators found that the snail hydraulically propels the spear through the tip of its proboscis. Pressure builds behind it until it shoots forward at insane speed.

In the fish-hunting species Conus catus, the strike takes less than 100 microseconds. Its peak acceleration exceeds 280,000 meters per second squared, similar to a fired bullet, making it the fastest movement measured in a mollusk by roughly an order of magnitude.

That speed solves an obvious evolutionary quandary: A snail is slow. A fish is fast. To catch one, the snail’s weapon must strike before the fish has time to escape. Evolution never ceases to amaze.

Cosman collected shells because he loved them. He apparently never imagined that his meticulous private collection would become a scientific archive. And today, the shells are helping researchers reconstruct past oceans, identify species, recover genetic information, and investigate toxins that act on the nervous system. Not bad for a yacht salesman.

The collections is digitized and all of the findings in the lab will eventually be made available to the broader scientific community. And so, what looks at first like a room filled with strangely beautiful shells is actually a small, but important library of marine life. And scientists are still learning how to read it.

Sometimes you just have to get the f*ck out.

For five days last week, four buddies and I hiked the Rae Lakes Loop through Kings Canyon National Park, and while I feel like saying that I almost died doing so, that’s really not true at all. It was hard, but I LOVED it. The trail spanned about 45 miles, with roughly 7,000 feet of elevation gain. The high point was Glen Pass, at 11,926 feet.

The first three days, we climbed from about 5,000 feet to over 11,900. Up, up, up. Such a grind. Some days, we walked for ten hours. The trail climbed steadily through forest, along rivers and past the raw granite towers of the High Sierra. At the permit station, my pack weighed in at 46 pounds, BEFORE filling up my three-liter water bladder (thank GOD for that bladder). My feet ached; hell, my whole body ached. I had a very simple philosophy: don’t think about the pain, just put one foot after another. Try not to stop much; just keep powering through, even if it was quite slow at times.

All the while, but especially at the end of a vigorous day, there was something deeply satisfying about the effort. As I said, sometimes you just have to get out.

At home, an entire day can easily disappear into emails, errands, news, and social media. Some evenings I wonder what I actually accomplished. In the mountains, the answer was clear. We had climbed several thousand feet. We had crossed a pass. We had carried everything we needed ten miles deeper into the magnificent California wilderness.

One of my favorite living sci-fi writers, Kim Stanley Robinson, who also penned a wonderful memoir about these mountains called The High Sierra: A Love Story, has an excellent observation:

“Sometimes hiking involves a lot of looking down to be sure of your footing, but other times it’s like strolling up a sidewalk. Minute follows minute, they unspool with nothing in particular to mark their passing. You’re just walking, and you’re only going to be walking for the rest of that day. And so you begin to shift into hiking’s different time, its altered state of consciousness. Sierra time. In that morning light, at the start of a trip, I sometimes laugh out loud.”

I understand that rhythm. I know exactly what he’s talking about.

For five days, I paid zero attention to the news. Also, no social media and little connection to the outside world save for a few satellite texts to let my wife know that I was OK.

Yes, I took a lot of photos and videos. How else to preserve some of the more harrowing moments and the head-spinning landscapes? Still, as Robinson writes, “Very little of the high Sierra makes it into its images. If you see a pretty photo from the Sierras, you always have to remember, it was a zillion times more beautiful than that!” I am home now writing this and looking through shots I took. That comment is absolutely true.

When you walk that much, that far, gain that much altitude, you inevitably get very thirsty. But, amazingly, in this part of the Sierra, water is always there. Most of the hike passes along gurgling waterways like Bubbs Creek, Woods Creek, Charlotte Creek, and, of course, the South Fork of the Kings River. There are few things as satisfying as filling up your water bladder with the freshest, coldest water you’ve ever tasted, right from a gushing stream spilling out of the high peaks. My God, it tastes so good.

John Muir wrote, “Climb the mountains and get their good tidings. Nature’s peace will flow into you as sunshine flows into trees. The winds will blow their own freshness into you and the storms their energy, while cares will drop off like autumn leaves.” Like much of Muir’s writing, it’s a little overwrought, but it is also true. Nature has a powerful duality: it can be your worst enemy, and it can be your best friend. You don’t always get to set the terms of this relationship. On this trip, nature was kind, if at times a little ungentle. But she was never mean. There were no storms, no punishing winds, and no relentless sun. And, MY GOD, there were almost no mosquitoes. (For that, I have Reddit to thank. Several people recommended hiking the loop in August, after the worst of mosquito season had passed. I had seen Instagram posts from June showing hikers being assaulted by swarms at some of the very places where we later pitched our tents in almost complete peace.)

And then there are the views. The long trudge up Bubbs Creek canyon, and the descent through Woods Creek and Paradise Valley on the other side of the loop, are flanked by sculpted granite towers that rise high and seem as smooth as table glass. I sometimes forget that these massive exposures of granite can be found throughout the Sierra, not just in Yosemite. Kings Canyon National Park is filled with them. They are exposed portions of the Sierra Nevada batholith (which I’ve written about before), formed from magma that cooled deep underground more than 80 million years ago. The rock was later lifted and exposed, then shaved by glaciers into the peaks, cliffs and immense U-shaped canyons we see today.

At Rae Lakes, the mountains seemingly rise out of the water. One peak called Painted Lady stands out, not just for its bulk, but also for its crazy layered look. Its black cap rests above wide bands of reddish and white rock. The colors signify different bodies of magma that cooled deep underground roughly 100 million years ago. Below, the mountain is surrounded by an enormous slope of crumbling scree that it seems to wear like a shawl across its shoulders.

At the end of our third day, after all that climbing up, up, up, we reached Glen Pass, at 11,926 feet. A cool breeze helped evaporate the sweat that had soaked through my clothes on the way there. We stared out across a landscape that opened in every direction, a vast sweep of peaks, lakes, and valleys. And thus began the next few days of interminable, knee-popping steps downhill.

The Rae Lakes Loop had felt enormous while I was toiling to conquer it. But when I later looked at a map of the region, I realized how small it really was: just a meager triangle in a mountain range that stretches hundreds of miles. Beyond are more trails, passes, lakes, and basins than I could possibly visit in a lifetime.

The Sierra Nevada is one of California’s great treasures. I never tire of visiting, and I will likely never stop, even when I can no longer haul my middle-aged ass across almost 50-miles of stunning wilderness. I’ll drive to a lake, sit there, and appreciate what nature hath wrought. How much better it is to sit there in quiet than to surrender another hour to the large language models, Netflix shows and Instagram posts that increasingly dominate our daily existence.

When I got home, I was tired and sore. Reconstituted meals now sounded horrible, even though I found them delicious (well, near-delicious) at high altitude. The soles of my Merrells had almost completely flopped off. But within a few days I felt as good as new, stronger even.

I cannot wait to go back.

I'm headed into the Sierra for a five-day backpacking trip, so there won't be a post next week. In the meantime, I hope you enjoy this piece on one of my favorite features along California's highways.

“Man is a geologic agent,” the late UC Davis geologist Eldridge Moores.

I’ve got a pretty consistent answer whenever someone asks, “Window or aisle?”

Window. Always.

I can spend an entire flight staring at the Earth below, trying to place myself on the map, guessing the familiar latticework of a particular city, admiring mountain ranges, or taking in the dull sprawl of the desert.

I’m the same way when I drive. I love looking out the window. And one thing I particularly enjoy looking more closely at is roadcuts.

Roadcuts are the places where highway builders blasted away hillsides and mountains to make room for the road. In doing so, they expose deep history.

Each one is different. Some reveal ancient seabeds. Others reveal rocks that were folded, fractured, or uplifted by plate tectonics. Many are bizarre and beautiful.

Once you start noticing them, you see them everywhere in California (sorry, Kansas). I’m not a geologist, although I took a geology class or two in school, and the discipline has always fascinated me. But you don’t need to have a Ph.D to appreciate the stories that roadcuts can tell us.

To get those stories, though, you will probably have to read a book or two, or talk to a geologist. Both of which I did for this story.

“Geologists on the whole are inconsistent drivers. When a roadcut presents itself, they tend to lurch and weave,” wrote the great New Yorker writer John McPhee in his excellent book Annals of the Former World. “To them, the roadcut is a portal, a fragment of a regional story, a proscenium arch that leads their imaginations into the earth and through the surrounding terrane.”

When you spy a roadcut during a drive, you are seeing exposed layers of rock that have been hidden from view for millions of years. Each layer, or stratum, tells a story of what the environment was like when that layer was deposited. By studying these layers, geologists can reconstruct a timeline of events that shaped the region. For example, they can identify periods of volcanic activity, times when the area was submerged under an ancient ocean, or epochs when massive glaciers were carving out valleys.

“Road cuts are the best because, especially if they’re recent, you see what cannot be seen anywhere else,” said Donald Prothero, a California-based geologist, paleontologist, and author of many books, including the wonderful The Story of the Earth in 25 Rocks. “In Southern California, we’re lucky because of our dry climate, we can go to the Mojave Desert — as I did through my entire college career at Riverside — and see lots of stuff that doesn’t require digging a hole.”

California is especially interesting due to its active tectonic setting, which is, of course, why we have so many earthquakes. It’s not just the San Andreas Fault that fires up geologists; there are numerous lesser-known faults that crisscross the state, and roadcuts can expose these hidden fractures. By studying the composition of rocks along these faults, geologists learn about the nature of past seismic activity and can make predictions about future earthquakes.

The rock composition in California varies widely, crazily so.

“We have everything,” Prothero told me. “We have everything from billion-year-old, multi-billion-year-old rocks, up to volcanoes that erupted as recently as 1912. We have fault zones, we have subduction zones. We have everything from the oldest to the youngest, almost every geologic phenomenon you can imagine, we have.”

In the Sierra Nevada, granite roadcuts tell of a time when massive chambers of magma slowly cooled and crystallized deep beneath the Earth’s surface. Elsewhere, roadcuts through sedimentary rocks like sandstone and shale may contain fossils, giving clues about the life forms that once inhabited the region.

In roadcuts, geologists might find evidence of powerful geological processes such as metamorphism, where existing rock types are transformed into new types due to high pressure and temperature conditions. For instance, the presence of metamorphic rocks like schist and gneiss can indicate ancient collision zones where Earth’s tectonic plates have crashed together.

The value of California roadcuts is wonderfully illustrated in John McPhee’s “Assembling California.” (It’s hard to write about California geology without citing McPhee). The book is a fascinating narrative that weaves together the tale of California’s complex geology with the lives of the geologists who study it. One of McPhee’s favorite geologists was Eldridge Moores, from the University of California, Davis (Moores died in 2018). Moores played a significant role in deciphering the geological history of the region, particularly through his fieldwork involving, yes, roadcuts.

At the time Moores entered the field, the theory of plate tectonics was only beginning to gain traction. In the early 1960s, the idea that continents drifted and that vast slabs of the Earth’s crust moved over the mantle was still controversial, and it was met with extreme skepticism by many geologists trained in older, “fixist” models. Moores, however, embraced the theory early, recognizing in it an explanation for the chaotic structures he saw in California’s mountain belts. As a young researcher, he studied the Troodos ophiolite in Cyprus, an exposed section of ancient oceanic crust, and realized that similar rock assemblages were scattered across California.

“It was a very exciting time. I still get goosebumps even talking about it,” Moores told KQED in 2017. “A turning point, I think it was, in the plate tectonic revolution, that was the watershed of geology.”

Moores understood that the rocks he saw in California were remnants of vanished oceans, relics of seafloor that had been uplifted and accreted onto the edge of North America. His work helped reveal that much of California had arrived in pieces, a geological patchwork of island arcs, deep-sea basins, and continental fragments welded together by subduction. While others were still debating the validity of plate tectonics, Moores was already applying it, using it to decode the assembly of an entire state.

Moores was renowned for his work on ophiolites, sections of the ocean floor that have been thrust up onto the continent. One of his notable discoveries was the identification of ophiolite sequences in the roadcuts along the highways of the Sierra Nevada. These discoveries were crucial in understanding the ancient tectonic movements that shaped western North America.

Through roadcuts, Moores and his colleagues were able to observe and study the juxtaposition of different rock types. They could literally walk along the cuts and see how different terranes, or large packets of rock with a distinct geological history, were stitched together like a geological quilt, offering insight into the past locations of tectonic plates.

“Nature is messy,” Moores once told McPhee. “Don’t expect it to be uniform and consistent.”

He also meant: California is messy.

There are thousands of roadcuts across California; each one is different, and each tells a slightly different story. The Palmdale Roadcut, which I have visited many times, is a fascinating geological feature along the San Andreas Fault. It has been an invaluable resource for geologists studying the dynamics of this world-famous fault line.

“It’s a pressure ridge,” says Prothero. “The fault line strikes left, right, sliding horizontally, but there’s always compression on it. So it generates these pressure ridges in multiple places, and that’s when the bed’s exposed. They’re all crumpled up like a carpet. So that’s how much horizontal compression has existed. If you flatten that thing out, it’d be twice as wide.”

The rock here is a chaotic mélange: fault gouge, shattered granite, and twisted layers of sedimentary rock that have been pulverized and ground together by the powerful motion of the Pacific and North American plates, grinding past one another. By analyzing these layers, geologists can better understand the history and behavior of the San Andreas Fault, including the patterns of past earthquakes and the movements of tectonic plates. This, in turn, contributes significantly to the broader understanding of seismic risks and aids in preparing for future seismic events.

Another one of California’s well-known roadcuts, the Charlie Brown Outcrop, is located along Highway 178 near the Nevada border. It has been highlighted by geology teacher Garry Hayes, author of the Geotripper blog. Hayes writes:

“There are really three stories told in this exposure, that of distant ash eruptions, a violent eruption close by, and earthquakes with associated mountain-building.”

Roadcuts are also crucial for educating the next generation of geologists. What could be more exciting for a budding geologist than a road trip? All the geologists I know, and I know a few, say this is the most fun a geologist can have. They allow students to identify rock types while piecing together the geologic history recorded in the rocks.

Prothero loves taking drives into the Sierra (who doesn’t?) “You’ve got things like the Alabama Hills. And then the other side, the White Mountains and the Inyo Mountains. All those have spectacular geology.”

Prothero also has a favorite roadcut up in the San Gabriel Mountains near Angeles Forest Highway that he takes students to see. “It’s a really nice outcrop because it’s cut right through almost all the bedrock that you have in the San Gabriel Mountains,” he told me. “We had students sketch in where the faults are and figure out the sequence of events like we do in a class exercise. But this is real. And I don’t think there’s any place in the country where you can do that so easily.”

In Assembling California, McPhee remarked that “geologists are like dermatologists: they study, for the most part, the outermost two per cent of the earth. They crawl around like fleas on the world’s tough hide, exploring every wrinkle and crease, and try to figure out what makes the animal move.”

Basically, roadcuts are not just the incidental byproduct of infrastructure development; they are key to understanding California’s complex geological evolution. Think of them as windows, exposing part of Earth’s history that would otherwise remain hidden underground. They're an invitation to see the landscape differently. Once you have even a small sense of what you're looking at, an ordinary drive through California becomes part of a much bigger story.

Back in 2023, scientists surveying a vast military-industrial dumpsite in the deep ocean off Southern California were looking for barrels and other remnants of decades of industrial and military dumping. They found plenty of it. They had discovered an astonishing amount of it during earlier surveys and were now expanding the search across a much larger area of the seafloor.

There was a very unfortunate period after World War II when it wasn’t considered a big deal to take all your poisonous, caustic garbage — let alone unused munitions — and simply toss them over the side of a ship, letting it sink to the seafloor and do God-knows-what to the environment.

That’s a terrible story, and the Los Angeles Times broke the scandal back in 2022. But that’s not what I found most interesting about the recent survey. Along with all the barrels and old munitions, scientists also found an extraordinary number of whale skeletons on the seafloor. So many, in fact, that some researchers believe Southern California could be home to one of the largest whale graveyards in the world.

Seven whale carcasses were confirmed with underwater video. Sonar data suggested that more than 60 may lie within the surveyed area. These sunken carcasses are known as “whale falls.”

That may not be entirely surprising. California sits beside one of the world’s great whale corridors. Over the course of any given year, tens of thousands of large whales migrate through or feed in the waters off our coast, many within sight of land. Grays, blues, humpbacks and fin whales love the rich waters of the California Current, which can be abundant in food.

Still, the concentration found off Los Angeles was remarkable. Before the Scripps surveys, scientists had documented only about 50 naturally occurring whale falls across the world’s oceans. The possible discovery of more than 60 in one relatively small area would make the San Pedro Basin one of the greatest known concentrations of whale remains anywhere on Earth.

There is no evidence that the deaths were connected to the industrial waste or military munitions found nearby. The skeletons probably accumulated over many decades. The basin’s extremely low oxygen levels slow decomposition, while its low sedimentation rate may leave the bones exposed rather than burying them.

Dead whales on the ocean floor may seem like a nothing burger to most of us. But to scientists, they can be a bounty of information about what happens in the deep ocean, a place humans have barely explored. Studying the biological processes around whale falls can tell us a great deal not only about life in the depths, but also about how carbon is sequestered, how nutrients move through the ocean, and how isolated deep-sea communities survive and spread.

I recently interviewed Dr. Jeffrey Marlow, a marine microbiologist and assistant professor of biology at Boston University. Marlow is also the author of The Dark Frontier: Unlocking the Secrets of the Deep Sea, a fascinating new book that explores life around hydrothermal vents, methane seeps, whale falls and other places where microorganisms help sustain much of the deep ocean.

I asked him in particular about the value of whale falls to scientists trying to understand what life is like in the murky depths.

“Most of the seafloor is actually pretty barren,” Marlow told me. “A lot of the organisms down there depend on food falling from above. Often it’s tiny pieces we call marine snow, roughly the size and shape of snowflakes.”

A whale fall delivers that food in one enormous pulse.

“Every now and then, something huge, like a whale carcass, falls to the seafloor,” Marlow said. “That is an enormous amount of food, and it causes these oases to bloom on the seafloor.”

When a carcass reaches the bottom, large scavengers such as hagfish (ugly), sleeper sharks and crabs begin stripping away its skin, blubber and muscle. Smaller animals then colonize the remaining skeleton and the nutrient-rich sediment around it.

One of the strangest animals is a bone-eating worm called Osedax. They have no mouth or digestive system. Instead, root-like tissues penetrate and dissolve the bones, absorbing collagen and lipids (basically fats). The roots contain symbiotic bacteria that appear to play an important role in the worms’ nutrition.

Marlow has seen these worms firsthand at a whale fall off San Diego known as Rosebud, and he writes about it in the book. The whale had been killed by a ship several years earlier, giving Scripps marine biologist Greg Rouse a rare opportunity to follow the ecosystem from a known starting point. Rouse and his team towed the whale carcass out to sea and sank it in deep water.

“Most of the time, scientists come across whale falls that just happen to be there, which means we don’t know how long they’ve been there or what stage of ecological succession they’re in,” Marlow said. “But if you’re able to start the clock from zero, that is an exciting opportunity.”

Marlow visited Rosebud roughly five years after the whale’s death. Large scavengers had consumed most of the soft tissue, although some fleshy bits remained.

“What interested me most were these tufts of fluffy, feather-like shapes on the bones,” Marlow said, referring to the bone-eating Osedax worms. “They work because they have microbes inside of them that are able to break down the tough fibers of whale bone and release nutrients.”

Marlow described it as “a really interesting endosymbiosis, where a microbe and an animal, in partnership, unlock new habitats for each of them.”

As decomposition continues, microbes break down organic compounds in and around the bones, generating hydrogen sulfide (which smells like rotten eggs). Other microorganisms use that chemical as an energy source, supporting communities that can include mussels, clams, worms and snails. This way of generating energy without light is known as chemosynthesis, and its pervasiveness in supporting life in the deep was largely unknown to science until relatively recently.

Scientists do not know exactly how long the final stages of the breakdown of a whale fall can continue.

“We think this is probably the longest part of whale-fall succession,” Marlow said of the bone-eating stage. “The bone-eating worms can break it down over decades. We don’t really know how a whale-fall ecosystem ends. It may be even a century or two.”

I have seen many whales off the California coast during my adventures. Just two years ago, I filmed a blue whale with my drone off Newport. I have also swum with and filmed blue whales off Sri Lanka for a documentary. They are breathtakingly big. Having one swim past you is like watching a train arrive in the New York subway.

The concentration of whale falls off the coast of California is fascinating and a boon to science. But it is also worth remembering that whales here face the constant danger of ship strikes, although scientists do not yet know what killed the whales found in the San Pedro Basin. So I’ll end today’s piece with a quick shout-out to the folks at UC Santa Barbara’s Benioff Ocean Science Laboratory. They developed Whale Safe, a system that was built to warn large container vessels when whales may be nearby and encourage them to slow down.

Perhaps a bit of sage advice for all of us.

“Future generations are going to forgive us our horrible genocidal wars, because they’ll pass too far into history. They will forgive us the follies of earlier generations and much of the harm we caused. But they will not forgive us for having so carelessly thrown away a large part of the rest of life on our watch.”

That thought hit me like a slap last week as I walked through the Gibbon Conservation Center in Santa Clarita, which I visited with my colleague Tod Mesirow.

Despite being less than an hour from downtown Los Angeles, few Southern Californians know the center exists. Yet it is one of the world’s most important institutions devoted entirely to the conservation, study and captive breeding of gibbons, the world’s smallest apes. About 40 gibbons representing all four genera and five species live here. Researchers come from around the world to study their remarkable vocalizations, behavior, cognition and social lives.

Gibbons are extraordinary animals. They are true apes, sharing ancestry with orangutans, gorillas, chimpanzees and bonobos. They were once known as the “lesser apes,” but today the preferred term is “small apes,” recognizing that their smaller size does not make them any less, well, remarkable. Built almost entirely for life high in the rainforest canopies of Southeast Asia, they swing through the trees using a form of locomotion called brachiation and can reach speeds approaching 35 miles per hour. They are also incredible singers.

We found that out when we arrived just after sunrise.

At first there was only a long, haunting call, a single note. Then a whoop.

Then another.

Within moments the entire center erupted into an eye-widening chorus of hoots, whoops, melodious screams, and booming calls that echoed across the canyon. Every species has its own song, and together they created one of the most stunning wildlife experiences I have had anywhere. It is difficult to believe something this extraordinary happens every morning just outside Los Angeles.

I’m not going to sugarcoat it. The gibbons are all in enclosures. They do not have the vast treetop forests that they would roam through in their native habitat. But that’s only because so much of that habitat is being destroyed. It’s heartbreaking, but I also realize it’s better to have gibbons here than no gibbons at all.

The center is led by Gabriella Skollar, who first came here from Hungary in 2005 to study gibbons and eventually became its director. Along with a small, dedicated staff and volunteers, she oversees the daily care of the animals while continuing the center’s scientific mission. During our visit, we also met Jodi Kleier, an anthropology graduate from the University of Kansas with a fascination for gibbon skeletal anatomy, particularly their enlarged hyoid bones (bones in the neck which help them make their vocalizations). Kleier spends much of her day preparing diets and hand-feeding broccoli, fruit, and so-called monkey nuggets to the gibbons, which eagerly stretch out their absurdly long, hairy arms to grab each piece.

The Gibbon Conservation Center was founded in 1976 by the late Alan Mootnick, a largely self-taught gibbon expert who devoted his life to understanding and protecting these animals. What began with a single rescued gibbon has grown into one of the world’s premier centers for gibbon conservation and research. The center participates in breeding programs, supports field conservation, welcomes researchers, and educates thousands of visitors every year.

It also serves as a reminder of how precarious the future of these animals has become.

There are 20 recognized species of gibbons, all native to the forests of Southeast Asia. Every one of them is threatened, and several are critically endangered. The rarest, the Hainan gibbon of China, numbers fewer than 40 individuals in the wild, making it the world’s rarest primate.

Spend even a few minutes watching a gibbon — the curiosity, intelligence, agility, individuality — the list goes on, and Wilson’s words begin to sting. We live in an age obsessed with artificial intelligence and sophisticated machines. Our attention is dominated by screens and YouTube and Instagram and a seemingly endless political circus. Meanwhile, the natural world is disappearing around us. Every extinction represents millions of years of evolution erased forever, taking with it behaviors, relationships, and mysteries we are only beginning to comprehend.

Fortunately, this is also a story of hope, because the gibbons are there, for all to see.

The Gibbon Conservation Center is open to the public on weekends, offering guided tours that bring visitors face to face with some of our closest living relatives. Schoolchildren come through here every week. Families encounter a place they never knew existed. And if you arrive early enough, you’ll hear that crazy morning chorus, a sound you will never forget.

Wilson believed that future generations would judge us by how well we cared for the rest of life on Earth. All the organisms that are literally irreplaceable. Places like the Gibbon Conservation Center suggest that, at least in one small corner of California, there are still people working every day to preserve not only these remarkable apes, but also the sense of wonder that comes from knowing we share this planet with them.

(Please make sure to watch the video above. 👆🏻👆🏻👆🏻)

“A vision for ocean prosperity.” - Octavio Aburto

Cabo Pulmo, at the tip of the Baja Peninsula, is one of the world’s great marine conservation success stories. Just 100 kilometers (62 miles) northeast of Cabo San Lucas, this quiet fishing village lies next to the oldest coral reef on the west coast of North America. The reef itself is the northernmost coral reef of its kind and is estimated to be about 20,000 years old. Yet only a few decades ago, many feared it was going to be lost.

Last week, I dove the reef and surrounding waters of Cabo Pulmo with my two PADI-certified kids. Reaching Cabo Pulmo is not easy. The hot, lonely highway stretches for miles through an arid landscape of towering cardón cacti and endless desert scrub. The final 15 miles are along a rutted, washboard dirt road. I was relieved that my rental car made it without incident. The village itself is tiny, little more than a single unpaved road lined with dilapidated buildings, most of them local dive outfitters. One small restaurant served what were probably the freshest and best fish tacos I’ve ever had. And I’ve had a lot of fish tacos

For generations, the families of Cabo Pulmo depended almost entirely on fishing. The reef supported abundant populations of grouper, snapper, jacks, sharks, and countless colorful reef fish. But by the 1980s and early 1990s, decades of commercial and artisanal fishing had severely depleted marine life there. Local fishermen watched catches shrink year after year. Rather than continuing to exploit a collapsing ecosystem, many reached an astonishing conclusion: perhaps the best way to save their future was to stop fishing. Altogether.

Led by local families including the Castro family, the community worked with Mexican scientists and conservationists to persuade the government to protect the reef. Their efforts paid off in 1995 when Mexico established Cabo Pulmo National Park, protecting roughly 71 square kilometers (27 square miles) of reef and surrounding waters. Although the initial plan allowed some fishing in portions of the park, local residents effectively treated the entire protected area as a no-take reserve, enforcing the rules themselves long before government enforcement came to be.

The recovery that followed has astonished marine scientists.

A landmark study led by marine ecologist Octavio Aburto, now an Associate Professor of Marine Biology at the Scripps Institution of Oceanography, compared underwater surveys conducted between 1999 and 2009. The researchers found that total reef fish biomass increased by a remarkable 463 percent, one of the largest recoveries ever documented inside a marine reserve. Top predators increased tenfold, while species diversity climbed dramatically as large schools of fish returned to the reef.

I talked to Aburto about Cabo Pulmo's extraordinary recovery, and he believes the reef offers a blueprint for what is possible elsewhere if ecosystems are given the chance to recover. "When I first arrived in the 1990s, we didn't see big animals," he said. "Since 2010, every year my team and I have gone back to Cabo Pulmo to monitor the marine life, and it has completely changed what we understand about reefs in the Gulf of California."

National Geographic Explorer Enric Sala, a co-author of the study, summarized the findings simply: “I could never have dreamt of such an extraordinary recovery of marine life at Cabo Pulmo.” Octavio Aburto wrote that “no other marine reserve in the world has shown such a fish recovery.”

Today, diving Cabo Pulmo is like entering an ocean that has largely disappeared elsewhere in the Gulf of California. The region is still known as the “The World’s Aquarium”, a term coined by the late Jacques Cousteau, but fish numbers in the Sea of Cortez have been in dramatic decline for a long time. But now, massive schools of bigeye jacks swirl into dense silver tornadoes. Green sea turtles glide calmly across the reef. Bull sharks patrol a cleaning station, while California sea lions, eagle rays, mobula rays, and occasionally mantas flap their underwater wings through the shallows. During the winter months, there are humpbacks and whale sharks. On our dive, even though it was murkier than I would have liked, we encountered giant groupers, snappers, porkfish, surgeonfish, angelfish, trumpetfish, moray eels, and dozens of species of tiny, colorful reef fish among the hard coral colonies. One school of yellow snapper we passed, or that passed us, consisted of several hundred fish, tightly aligned in formation. I’ve dived a lot of places in the world, and while Indonesia is still my favorite, Cabo Pulmo now ranks among one of my favorite places.

Scientists continue to study how this unusually resilient ecosystem has survived environmental changes that have devastated many coral reefs elsewhere in the Pacific. Cabo Pulmo has become an important natural laboratory for understanding reef resilience, fish biomass, predator recovery, and how healthy ecosystems respond when fishing pressure is removed. In California, we have established an impressive network of marine protected areas (MPAs), many of them less than two decades old. The oldest, around the Channel Islands, has become one of the clearest demonstrations of what can happen when fishing and other extractive activities are curtailed and marine ecosystems are given the opportunity to recover.

Marine protected areas are becoming increasingly popular around the world. The recently adopted High Seas Treaty, formally known as the Agreement on Biodiversity Beyond National Jurisdiction (BBNJ), is expected to accelerate the creation of new protected areas in international waters. But I have seen firsthand that simply drawing lines on a map and making grandiose declarations is not enough. Some reserves are basically paper parks, protected in name but still heavily exploited because of weak enforcement. That does not seem to be the case at Cabo Pulmo. Here, protection is taken seriously.

As Aburto explains, the recovery at Cabo Pulmo demonstrates two of the most important lessons in marine conservation. “Number one: Marine life can come back very fast, in this case, just 10 years. Number two: If the local people are involved in protection, you get the best results.”

Perhaps the biggest lesson from Cabo Pulmo goes beyond the impressive biology. There’s a critical people aspect to it that deserves recognition. Rather than choose between conservation and economic survival, the village transformed itself and the region. Former fishermen became dive guides, boat captains, and ecotourism operators. Among divers, Cabo Pulmo is widely regarded as one of the world’s must-see destinations. Visitors now travel from around the globe to experience the enormous schools of fish that helped make the reef famous through stunning photographs, including those shot by Octavio Aburto himself.

I was only able to do two dives during my trip. Normally, I would have been focused on photography and videography, but with my kids along, my attention was on them. The visibility during both dives was also fairly poor, so I knew I wasn’t going to capture the spectacular imagery I’d seen from photographers who have visited on better days. It didn’t matter. I was blown away by not only the sheer number of fish, but also by their size. Visiting Cabo Pulmo had been a dream of mine for years. Now the dream is to go back.

I’m in Cabo San Lucas this week, vacationing with my family but also preparing for a dive at the legendary Cabo Pulmo, widely regarded as one of the finest diving destinations in North America. Seeing it for myself has been a long-time goal, ever since I first learned how the local community successfully fought to protect the area by helping establish a marine protected area after plans emerged for a massive resort development nearby. This effort preserved one of the world’s most remarkable marine ecosystem and helped it recover, and I’m excited to finally experience it firsthand.

Being back in Baja also reminded me of another story that has fascinated me. The Baja California Peninsula is slowly pulling away from the North American continent. Yes, you read that right .

The article below has been extensively revised, expanded, and updated, and I hope you enjoy it.

Geological forces are always at work, reshaping the planet, just usually on a timescale too slow for us to notice. Geological time. But over the long haul, they can completely transform places we think of as fixed and familiar. I’m talking about places like Southern California and northern Mexico. I’ve been down to Baja a bunch of times, including a few unforgettable multi-day kayak trips in the Sea of Cortez. Paddling past towering cliffs and snoozing on empty beaches beneath the stars. So, it’s easy to feel like the landscape has been frozen in time.

But that sense of permanence? It’s an illusion.

Baja California stretches like a crooked old finger pointing toward the southern latitudes. This long, skinny slice of land, more than 1,200 miles from Mexicali to Cabo, is full of crazy contrasts like sun-blasted deserts, jagged mountains, fruitful oases, and (sadly, disappearing) mangroves. But it’s something more than a long peninsula: it’s actually a fracture. Baja was ripped from mainland Mexico by plodding tectonic forces. The Pacific Plate drags the land both north and west, creating a gap, now filled with ocean. But it’s still moving.

Every year, Baja creeps a little farther away from the continent, slowly widening the gap. Some scientists think that, millions of years from now, the rift could widen significantly and then flood with Pacific waters, turning parts of northern Mexico and even a large stretch of Southern California into a vast inland sea. The continent is cracking apart beeanth our feet. It’s just taking its time.

This process is linked to the activity of the San Andreas Fault and other associated fault systems, which collectively form a boundary between the Pacific Plate and the North American Plate (basically everything east). The movement of these plates is very slow, occurring over millions of years.

The separation is taking place at an average rate of about 2 to 5 centimeters per year. Over millions of years, perhaps as few as five million or as many as 20, these movements accumulate, leading to significant changes in the geography of the region.

“That sub-sea level area there will eventually rip apart far enough that the rest of the Pacific Ocean, the Gulf of California, will flow in. And so it won’t just be the Salton Sea. It’ll be a permanent ocean,” says California author and geologist Donald Prothero. Imagine that. A new ocean in what is today a vast desert where we are currently hoping to mine vast amounts of lithium.

The movement of the continental crust in the area is due in part to seafloor spreading at a massive underwater seam called the East Pacific Rise. This seam stretches from the southeastern Pacific near Antarctica all the way north into the Gulf of California. Its northernmost extension, known as the Gulf of California Rift Zone, reaches close to the mouth of the Colorado River, helping drive the slow separation of the Baja California Peninsula from mainland Mexico.

“Much of it is at or below sea level because of the rifting. So it’s just waiting for water to flood in,” says Prothero. Much is already flooded. We call that area the Sea of Cortez (and we also call it the Gulf of California). The Sea of Cortez is a geologically young sea, having formed around 5.3 million years ago when the Baja Peninsula began drifting northwest.

This body of water is a critical habitat for marine life, including several species of whales and dolphins that depend on its warm waters. Being there now, I can attets that the waters are indeed warm. Jacques Cousteau, the famous French oceanographer, famously referred to the Gulf of California as “the world’s aquarium” due to its vast array of (declining) marine life.

The Sea of Cortez today is under threat from our short time so far on the planet. Overfishing and pollution, including nitrogen-rich runoff from the Colorado River, which (sort of) flows directly into the gulf, imperils wildlife. Nutrient flows can lead to a dramatic decrease in oxygen, depriving plants and animals of air to breathe. The potential extinction of the critically endangered vaquita (Phocoena sinus), represents one of the most urgent conservation crises in the region. The vaquita is the world’s most endangered marine cetacean; only a few individuals remain. This dire situation is primarily due to bycatch in illegal gillnets used for fishing another endangered species, the totoaba fish, whose swim bladder is highly valued in traditional Chinese medicine.

Habitat destruction is another growing concern, as mangroves, estuaries, and reefs, key to the survival of millions of marine species, are increasingly destroyed to make way for tourism infrastructure and coastal development. Then there’s climate change, the unrelenting buggaboo of modern life, causing sea temperatures to rise along with ocean acidification and on and on. Of course, this is all happening at human time scales.

“The Gulf of California is a temporary feature,” says Prothero. It’s a place shaped by both human impact and tectonic drift. Baja California is slowly pulling away from mainland Mexico, a process that could one day create a vast inland sea and dramatically reshape the region. While no one alive today will witness the full transformation, its ultimate impacts will be extreme: redrawing coastlines, shifting ecosystems, and isolating parts of southern California and Mexico in ways we can scarcely imagine…even though, in its own way, it’s cool to try and do so.

Dr. Jeff Marlow has spent much of his career exploring some of the most extreme and least understood environments on Earth: The deep ocean. A microbiologist and assistant professor of biology at Boston University, Marlow studies the remarkable microorganisms that thrive in extreme places in the deep ocean.

Marlow is also the author of the recent book The Dark Frontier: Unlocking the Secrets of the Deep Sea, a fascinating exploration of how microbes help sustain life on Earth. It is excellent, and I highly recommend it.

Microbes are everywhere. They inhabit the oceans, the soil, the air we breathe, and even our own bodies (a good book on this last topic is I Contain Multitudes: The Microbes Within Us and a Grander View of Life by Ed Yong). Microbes also drive the biogeochemical cycles that make the planet habitable, influence the climate, and they form the foundation of ecosystems across the globe. Yet we are only beginning to understand what they do and the critical roles they play in Earth’s systems.

The diversity of microbial life is staggering. Scientists have estimated there may be as many as a trillion microbial species on Earth, with well under one percent formally described. But Marlow covers many other fascinating and timely topics as well, all of them very dear to me, including hydrothermal vents and the growing push to mine the deep ocean for so-called polymetallic nodules. This effort could help supply the metals needed for batteries and other green technologies, but it also threatens vast and poorly understood deep-sea ecosystems.

As readers of California Curated know, I believe the ocean and its health are among the most important issues facing humanity. Marlow’s book makes a compelling case that the deep sea is not a distant, disconnected realm. It is an essential part of the planet’s systems that support life on Earth, and understanding and protecting it may be one of the most important scientific challenges of our time.

Earlier this week, I spoke with him about whale falls, hydrothermal vents, deep-sea mining, California’s role in ocean science, and why microbes may be among the most important organisms on Earth. What follows is an edited and condensed version of our conversation.

Erik Olsen: I finished your book this morning, The Dark Frontier: Unlocking the Secrets of the Deep Sea, and I thought it was fascinating. One of the topics you write about was an experiment in California. It involved a so-called whale fall in San Diego. They called it Rosebud. Tell me about that expedition, what it meant, and what you learned. What surprised you most about the ecosystems that develop around whale falls?

Jeff Marlow: Whale falls are what happen when a whale dies and falls to the seafloor. Most of the seafloor is actually pretty barren. A lot of the organisms down there depend on food falling from above. Often it’s tiny pieces we call marine snow, roughly the size and shape of snowflakes.

But every now and then, something huge, like a whale carcass, falls to the seafloor. That is an enormous amount of food, and it causes these oases to bloom on the seafloor.

The one I visited is called Rosebud. A ship had killed the whale maybe five or six years earlier, and a scientist at Scripps Institution of Oceanography named Greg Rouse was on the lookout for exactly that kind of situation. Most of the time, scientists come across whale falls that just happen to be there, which means we don’t know how long they’ve been there or what stage of ecological succession they’re in.

But if you’re able to start the clock from zero, that is an exciting opportunity. We went out there about five years later. There was still a little bit of flesh around. Normally the hagfish, sharks, and big fish come in first and eat the meat off the bones.

What interested me most were these tufts of fluffy, feather-like shapes on the bones. Those are bone-eating worms called Osedax. They work because they have microbes inside of them that are able to break down the tough fibers of whale bone and release nutrients.

It’s a really interesting endosymbiosis, where a microbe and an animal, in partnership, unlock new habitats for each of them. We think this is probably the longest part of whale-fall succession. The bone-eating worms can break it down over decades. We don’t really know how a whale-fall ecosystem ends. It probably goes for decades, maybe even a century or two.

Erik Olsen: Like so many deep-sea systems, they’re aided by microbes. One of the magnificent discoveries was in 1977 off the Galápagos, when scientists discovered these vent systems teeming with life. We learned that a massive amount of life beyond the reach of light gets by through chemosynthesis. Is that still a “my gosh” moment? How far have we come in understanding these organisms?

Jeff Marlow: Absolutely. I think that was one of the most important discoveries in all of biology. I might be a little biased, but I think it still stands as a huge, transformative moment.

With whale falls, the energy and food and nutrients are coming from above, which means ultimately they come back to the sun. Whales eat plankton or fish or something else that ultimately ties back to photosynthesis and the sun as a source of energy.

The discovery of hydrothermal vents completely changed that because it meant energy could come from below. It could come from inside the planet in a way that sustains microbes first, and then ultimately animals and larger ecosystems.

Today, we know there are many more types of chemosynthetic sites than we imagined. There are hydrothermal vents, which were found first, but even within that category there are many different versions based on chemistry, rocks, and temperatures.

Then there are methane seeps, where methane comes out of the seafloor and fuels microbes and animals. So 1977 was the start, and we’re still trying to understand the full range of chemosynthetic sites on the seafloor.

Jeff Marlow discusses the staggering diversity of microbes and how scientists are still discovering entirely new branches of the tree of life.

Erik Olsen: Do we have a sense of the diversity of life among microbes? Where do you think we are in terms of fully understanding the breadth of the microbial universe?

Jeff Marlow: It’s hard to say. There are so many sequencing studies where people collect microbes, extract their DNA, and read their sequences that you might think we have a pretty decent handle on the overall picture.

And yet, every now and then, there’s a study that blows it all wide open. Even within the last decade, there have been studies revealing entire new branches of the tree of life, things like the Asgard archaea or the candidate phyla radiation, which is a whole branch of bacteria.

Those discoveries make you wonder whether we’ve found it all. We certainly haven’t found every species, far from it. But even at the level of big families or higher groupings of organisms, we’re still figuring things out.

There have been estimates that there are a trillion different microbial species. I don’t know how many we’ve characterized or sequenced, but certainly far fewer than one percent of that. There is a lot more out there.

Erik Olsen: I was trying to articulate to a friend recently that if you took a cubic centimeter of almost any air or water on the planet, in almost any place, you would find life. Would that be accurate?

Jeff Marlow: Absolutely. The rule of thumb I like to teach my students is that in a cubic centimeter of air, you might have one to ten microbes. That means every breath you take probably contains about a hundred.

In that same cubic centimeter of water, maybe you have a million. In soil, you may have a billion individual microbes. In some of the richest soils, that same cubic centimeter has more microbes than all the humans on Earth.

They’re everywhere.

Erik Olsen: You did your PhD at Caltech. Given your experience here, what is your thought about California as an ecosystem and as an ocean biology hotspot?

Jeff Marlow: California was completely formative for my way of thinking about microbes and their place in the world, and the way geological and biological forces interact.

My undergraduate degree and initial training were in geology, and the biology came later, so I have always viewed them as connected and inseparable. That becomes glaringly obvious in California.

It is also an interesting blend of exploration and exploitation, which I highlight in the book. Most obviously in Southern California, oil drilling was pretty straightforward because oil had been seeping out of the ground for centuries. The La Brea Tar Pits are a great example.

That set off much of the oil drilling industry offshore, as well as some of the fundamental science we’re talking about. The same microbes that are eating methane at these chemosynthetic sites and building interesting ecosystems that might inform the search for life beyond Earth are connected to the processes that led to offshore oil drilling.

It all converges in really interesting ways in California.

Erik Olsen: Deep-sea mining is one of the dominant ocean topics of the age. What makes it so important, why should we be concerned, and where do you think it’s headed?

Jeff Marlow: It is such an interesting, complicated, and challenging issue.

Let’s start with science. The challenge is that we know very little about these environments. There are a few types of seafloor sites that companies are interested in mining to get metals like copper, nickel, cobalt, and zinc, which could fuel battery technology and help move us away from fossil fuels.

On the face of it, that sounds great. It’s an environmental argument for getting rid of a carbon economy. The challenge is that we would be going to areas that have not yet been affected by human influence and scraping up the seafloor to get those metals.

Hydrothermal vents have been proposed as one place to get them, but the community has pretty effectively said that these are important areas for biodiversity and volatile environments where we don’t really know how magma systems would respond to mining.

The area now on the front lines is the Clarion-Clipperton Zone in the middle of the Pacific Ocean. This area has polymetallic nodules, little rocks covering the seafloor across much of the region. We don’t have a great sense of what all lives there or what biogeochemistry those nodules enable.

Removing them and disrupting this ancient ecosystem, which takes millions of years to form, would have more or less irreversible impacts. We don’t know exactly what those impacts are, but they could be significant in terms of nutrient cycling and other processes.

Note: The High Seas Treaty is the first major international agreement focused on protecting biodiversity in waters beyond any nation’s borders. As of 2026, the treaty has been signed by dozens of nations but has not yet entered into force. It creates a framework for marine protected areas, environmental reviews, and scientific cooperation on the high seas. Marlow advised several national delegations on scientific aspects of the treaty during negotiations.

Erik Olsen: What impact do you think the High Seas Treaty and the biodiversity beyond national jurisdiction process will have?

Jeff Marlow: It’s hard to say. I don’t mean to dodge the question, but I have no idea where we’ll end up.

The High Seas Treaty is not the primary legislation controlling deep-sea mining. That would be the International Seabed Authority, which is based in Jamaica and has domain over the seafloor and the resources below it. That group has been developing regulations for many years. They are not enormously close to a final version, but they are working on it.

In addition to the scientific questions of whether we should even consider this, there are major economic challenges. One question is whether it will be economically viable. There are smart economists questioning that.

The second question is what the International Seabed Authority and the UN propose to do with any money that comes in. In theory, these areas beyond national jurisdiction are the common heritage of humankind. That phrase appears in a lot of UN texts. So the profits from any exploitation of those resources should be distributed pretty equally.

We are currently far from that. Often, only single-digit percentages of any profits are likely to accrue to the global community.

So economically, scientifically, and logistically, things are challenging. We are not there quite yet, but it could still come together in the coming years.

Erik Olsen: As a scientist, what do you think we should be doing?

Jeff Marlow: The first order of business is to understand what is happening in these environments. In that sense, it is a precautionary approach. These places take millions of years to form, and they could be doing important things for the planet.

I have a thought exercise in the book where I imagine the first Victorian-era coal power plant writing an environmental impact statement. You can imagine them saying, “We burn this coal and it turns into an odorless, invisible gas. There’s no issue. Let’s move ahead.”

The point is that these things have long inertia cycles. If we start changing things, it is very hard to get back on course.

For now, I don’t think it is necessarily the best decision to start mining the deep sea. But I also like to think I’m a realist. We do currently need these metals from somewhere, and right now, one alternative is the Indonesian rainforest. It is not an easy calculus. We need to be aware of all the trade-offs implied by blocking off one area in favor of another.

Erik Olsen: What is your feeling about the further development of human-occupied submersibles? Is this something we need to put more money and effort into, and why? What is the difference between that and ROVs or AUVs?

Jeff Marlow: The most straightforward answer is that any version of accessing and interacting with the deep sea is valuable. We need all of these.

With ROVs, we are typically able to stay down longer. There aren’t human systems that need to breathe and eat, so ROV dives can be much longer. You can also get live footage back to a ship or even online, which means many more people can participate in the dive and help determine the best area to sample or explore.

But you are missing the visceral, in-person experience and the almost spiritual experience of being immersed in this realm that is the vast majority of our planet.

As an outreach tool, and as a way to get people to understand the ocean in a more embodied way, human-occupied vehicles are essential.

I’m also intrigued by the idea of psychological distance. The more distant you are from something, the more you focus on big-picture items. Distance can mean physically distant or emotionally distant. If you are very close to something, you look more at the details.

I don’t have data to back this up yet, but I’m interested in the idea that the type of science we do is probably different. If you are there in person, maybe you are looking at intricate details with your nose a few inches from a snail, worm, or hydrothermal vent. If you are seeing the same thing from your office, maybe you are focusing more on global-scale processes and bigger-picture interactions.

There are clear differences that we understand, and probably others that we don’t. But we really need them all.

Erik Olsen: What compelled you to write The Dark Frontier: Unlocking the Secrets of the Deep Sea? What was the key message you were trying to deliver?

Jeff Marlow: Two things made me want to write it.

First, I have been enormously privileged to have a front-row seat to these exploratory efforts. Being able to go down in Alvin and see these microbes, rocks, and smelly sediments up close, and then spend years with them in the lab, has made me understand that these places matter so much.

They are things we are only beginning to understand, but they are the foundation of our planet and capable of amazing things that creative scientists are still piecing together. I wanted to share more broadly what I have learned and the intellectual journey I have been on.

The other reason is that in coming into contact with so many amazing scientists and policymakers, I wanted to tell as many stories as I could. The deep sea is huge. The book really just scratches the surface.

I wanted to take a mostly journalistic approach and talk about the history of deep-sea science, whale falls, hydrothermal vents, methane seeps, outer space, deep-sea oil, potential deep-sea mining, and policy at places like the UN.

I was hoping to provide a kaleidoscopic view of the ocean within thirteen chapters. Hopefully, the book at least makes a start at that.

Erik Olsen: You are a scientist, but you’ve also become a science communicator. How difficult was that transition, and what has been your key takeaway?

Jeff Marlow: I think I’ve landed on two things.

First, people want to read about people. Many readers are interested in the science and the natural history, but having it reflected through the viewpoint of a person is often a great way in. I try to center a lot of things around that idea. Those people do not need to be people just like us. Diverse communities and scientists around the world can be a great way into interesting science.

Second, I think you can lose precision but keep accuracy. I don’t need to tell you every single detail of how we do DNA extractions or stain microbes under a microscope. But I can still be completely accurate and tell you truthful things about how it works and why it matters.

Tuning that level of detail is important, but we never want to stray too far from what is true and based on evidence.

Erik Olsen: Why should people care about microbes?

Jeff Marlow: They are the foundation of life on Earth. They form our microbiomes and help us digest food and interact with the broader environment. They fuel the biogeochemical cycles that establish habitable environments for everything else.

We are also finding that they are important players in climate regulation. A lot of the organisms I study turn methane into carbonate rock and lock up carbon in long-term repositories.

Finally, there is still so much diversity out there that we don’t understand. That matters for global processes, but also for things that might be more directly applicable, like medicines, industrial enzymes, and bioprospecting.

Microbes are a huge blind spot. They are hard to see, hard to photograph, and hard to build evocative stories around in the way we can with animals. It is an uphill battle in terms of emotional resonance.

But in terms of the rationale for studying and prioritizing microbes, I think it is very clear.

Erik Olsen: Well, Jeff, thank you very much.

Jeff Marlow: Of course, thank you.

We Californians are lucky. The reasons are almost endless. You can start with the mountains, deserts, forests, and coastline, but California’s good fortune goes beyond scenery. The state is also rich in the natural resources that helped shape its history, that built the fourth largest economy in the world. There was gold, of course. There were vast forests that supplied timber for booming cities and expanding railroads. There was/is fertile farmland (remember this piece on the Central Valley?) and relatively abundant water. The list goes on.

But one of the resources that transformed California more than almost any other was oil. For much of the twentieth century, California was one of the world’s great oil-producing regions. And a big part of that story traces back to an unusual geologic formation that lies beneath large stretches of the California coast. Known as the Monterey Formation, this ancient layer of rock proved exceptionally good at generating, trapping, and storing petroleum over millions of years, creating the deposits that would help fuel the state’s growth and prosperity.

Scientists at NASA Jet Propulsion Laboratory have described it as “California’s primary petroleum source rock.”

At the heart of the Monterey Formation’s geology is the unique composition of many different types of rock that come together in such a way that they create an ideal environment for trapping oil. The vast formation creates a complex network of porous and permeable spaces, allowing oil to migrate into these reservoirs. Over time, these rocks act like natural sponges, effectively capturing and holding large quantities of oil within their formations, making the Monterey Formation one of California’s most significant petroleum sources. It is estimated that over 38 billion barrels of oil have been produced to date from fields whose source rock is the Monterey.

So what is the formation made of? Well, there is diatomite, a light, porous rock formed from the fossilized remains of diatoms, microscopic algae with silica-rich shells that thrived in the nutrient-rich waters off California's coast millions of years ago. Another hallmark of the Monterey Formation is chert, a hard, silica-rich rock that often formed as those diatom-rich sediments were altered over time. Along with these rocks are organic-rich shales containing large amounts of kerogen, the waxy organic material derived from ancient marine life. All of this was buried and heated over millions of years, transforming the kerogen into the oil and natural gas that built the state’s economy. (Again, see my story on the history of the Long Beach oil industry).

Much of the pioneering research on the geology, formation, and unique composition of the Monterey Formation was conducted by the late Robert Garrison, a distinguished professor of oceanography at the University of California, Santa Cruz. Garrison was considered the foremost expert on the Monterey Foundation, and his work was instrumental in revealing how the Monterey Formation’s deposits were shaped by a combination of oceanographic upwelling, climatic shifts, and tectonic activity during the Miocene epoch.

The Monterey Formation is one of the most intensely studied petroleum formations in the world, helping geologists better understand how oil is generated, how it migrates through rock, and accumulates underground. But the Monterey Formation isn't just important beneath the surface. Its rocks are also among the most distinctive along the California coast. Walk along the beach near Crystal Cove in Orange County, for example, and examples of Monterey Formation rocks are everywhere. You can see the layering and porosity of these rocks all along the coast, and one result is the extensive network of tide pools that teem with marine life. As a kid growing up in Orange County, I spent countless hours exploring tide pools up and down the shoreline. Looking back, those experiences helped spark my fascination with the ocean and the remarkable creatures that live there.

Beyond its geological and economic significance, the Monterey Formation preserves an extraordinary record of ancient life. Its layers hold a variety of marine fossils, including diatoms, radiolarians, foraminifera, and coccolithophores. These microfossils offer a detailed look at past ocean conditions, helping scientists reconstruct the climatic and oceanographic history of the state. Additionally, the formation contains fossils of larger marine vertebrates, such as whales, seals, and fish, providing further insight into the ecosystems of ancient oceans.

The rock also has its drawbacks, particularly because it is prone to landslides. This makes some coastal areas of California, where the Monterey Formation is exposed, unsuitable for construction and development. Many recent news stories have documented the increasing rate at which the California coast is tumbling into the sea. An excellent recent book on the subject is Rosanna Xia’s California Against the Sea: Visions for Our Vanishing Coastline.

This unique formation is not just rock, it’s a detailed book that preserves millions of years of Earth’s history, from ancient marine ecosystems to dramatic shifts in climate as well as tectonic activity. We're fortunate that this remarkable formation exists. It helped create the oil resources that fueled much of California's growth, and it contributes to some of the most striking landscapes along our coast. Like so many of the state's natural gifts, we have benefited enormously from it. Having extracted that value, the challenge now is to understand it, protect it, and ensure that future generations can experience it as well.

The road to Lookout Mountain does not look out for you.

It peels off Highway 395 just south of Mono Lake as a washboard gravel track, climbs through sage and Jeffrey pine, and then simply stops pretending to be a road for cars. The last mile and a half is loose volcanic scree stacked into switchbacks, and my Honda Pilot, built for urban life and paved highways, did not like it. I almost bottomed out twice before I gave up trying to protect the oil pan and just committed. By the time I crested the final pitch and parked at 8,300 feet at the summit, the engine was hot, the AC was blasting, and the Eastern Sierra sun was directly overhead, blazing down on me.

I got out into a wall of heat, and what looked like thousands of shards of glass blinked back at me.

It was everywhere. Underfoot, in every direction. I crouched down to look closer, and the glitter resolved into something else: black, glassy, sharp-edged stone. Obsidian, and not a few pieces, but what looked like millions, carpeted the entire summit.

Some pieces were fist-sized chunks, blocky, raw, and covered in dust. Others were thin, almost translucent flakes that were so sharp, you could easily cut a piece of meat. Or a finger. I considered for a moment how lucky I was that I had not popped a tire on the way up. Basically, everywhere I looked were little black knives, sitting in the dirt.

I am producing a video about the area, the obsidian here, and its wide use among indigenous people in California, and so I set up on the summit and stood in front of my camera to record a few standups. Within ten minutes, my camera had overheated and shut down (it’s a Sony A7V). I had to go back into the car, turn on the AC, and let things cool down.

Much of the summit of Lookout Mountain is capped in obsidian, and according to a 2023 paper published in the IAOS Bulletin, the mountain, along with the broader Casa Diablo obsidian complex, was “one of the most significant toolstone quarries in California” in pre-colonial times.

The obsidian at Lookout Mountain is exceptionally pure. According to the U.S. Geological Survey (USGS), unlike some obsidian deposits, it lacks visible crystals and vesicles (gas bubbles), which is what allows it to fracture predictably into razor-sharp edges. Thousands of years ago, Indigenous people came here to quarry this volcanic glass and turn it into tools that were traded across the West.

What’s fascinating is that when you’re standing on Lookout Mountain, you can also see other volcanic features such as Obsidian Dome, Glass Creek Dome, and the Inyo Craters, all much younger than the summit I was on. In a single panorama, you’re looking at hundreds of thousands of years of volcanic activity. Lookout Mountain itself erupted roughly 677,000 to 692,000 years ago, while Obsidian Dome and its neighbors across the valley are infants by comparison, having erupted roughly 600 to 650 years ago.

You might think Obsidian Dome, a glassy mound nearly a mile across, would have made just as fine a quarry as Lookout Mountain. Geologically, though, the two are not quite the same kind of glass. Drill cores taken from Obsidian Dome by researchers in the 1980s show its obsidian is shot through with tiny embedded mineral crystals, the result of slower cooling, while that from Lookout Mountain is more pure and much older.

Whether that difference actually steered prehistoric toolmakers toward one mountain over the other isn’t something I found any direct support for, but it would make sense given the predominance of Lookout Mountain/Casa Diablo obsidian that has been found in tools found around California.

I would have thought obsidian is obsidian, wherever it erupted. It turns out you can tell exactly where a piece came from, and quite accurately. That fact has become a boon to archaeologists trying to reconstruct the lives, migration patterns, and trading practices of early Californians.

Here’s how it works:

Obsidian is volcanic glass. It cools too fast to form crystals, and in that speed, it does something enormously useful to scientists much later on: it locks in the precise trace-element chemistry of the exact magma that produced it. It’s complicated stuff, and I don’t profess to understand it, but ratios of zirconium, strontium, rubidium, barium, and rare earth elements vary, often quite narrowly, from eruption to eruption. No two volcanic sources produce identical chemistry, and within a single field like this one, even neighboring outcrops can be told apart.

That’s the basis of obsidian sourcing. Using portable X-ray fluorescence (XRF) units or laser-induced breakdown spectroscopy (LIBS), researchers fire a beam at a piece of obsidian and read back its elemental signature, resulting in a specific geochemical fingerprint. That fingerprint gets compared against a reference library built from known volcanic sources and is fine enough to distinguish one dome from its neighbor a few miles away.

I more or less got the idea for this story from Kim Stanley Robinson’s marvelous book The High Sierra: A Love Story, where he put it like this: “Scientists can identify by chemical composition where obsidian flakes originated, and they can even determine when chips or tools were flaked, by measuring how far water has penetrated any newly exposed glass surfaces; this happens at a regular and measurable rate (which I find amazing).”

Amazing is the right word.

That second technique Robinson mentions is what lets archaeologists put a date on the glass itself. Obsidian absorbs water from the air after it’s freshly broken, forming a microscopic rim that thickens steadily over time. The rim is visible under microscopy. The technique dates back to 1960, and lets researchers estimate, often within a few centuries, how long ago a given flake was struck. Combine the two and you can figure out not just where a tool came from, but when.

Many of the millions of little pieces around me on Lookout Mountain were almost certainly debitage, not only a cool-sounding noun, but also the technical word for knapping waste, because there were so many small flakes everywhere. At least I’d like to think so. And there is some documentation to back that up. If true, then I wasn’t just standing on a random summit, or a natural aggregation of obsidian, but on a workshop.

The people working the obsidian here were almost certainly ancestors of the Kootzaduka’a, the southernmost band of the Northern Paiute, who have resided in the Mono Basin region for more than 6,000 years. Obsidian was immensely valuable, like the microchips of the day. It was used not just for arrowheads and spear points, but also for scrapers to get meat and fat off animal hides, among many other uses.

The Kootzaduka’a carried obsidian west across the Sierra into Yosemite, trading with Miwok groups who had none of their own. But the chemistry shows the longest journeys ran south: Casa Diablo/Mount Lookout obsidian dominates sites in the San Joaquin Valley from the Merced River down to Tulare Lake, and it has turned up among Chumash trade goods on the Southern California coast, nearly two hundred miles away. The stones were likely carried hand to hand through what archaeologists call “down-the-line exchange,” a relay of trading partners, rather than one continuous trip.

Perhaps the most surprising thing to me is that obsidian made its way all the way to the Channel Islands, where XRF analysis of 69 obsidian artifacts from 28 island sites found Chumash and Tongva peoples obtaining obsidian from at least five eastern California sources, including Casa Diablo, through an exchange running across thousands of years.

After about two hours of filming, exploring, chilling in the car and wiping sweat off my face, I headed back down the rough road to Mammoth Lakes. I’d gone up that mountain to film some glittering rocks for a story that kind of fascinated me. But I came down having stood, basically, in the middle of one of prehistoric California’s longest supply chains.

I’ve been up in the Eastern Sierra for the last few days driving around and filming a couple of cool stories I’ve got cooking. I spent a day exploring the Long Valley Caldera, one of the most interesting geologic sites in California, if not the United States. Then I went to Mono Lake and drove to the top of Lookout Mountain, which is covered in obsidian used by the indigenous tribes who once lived and thrived here.

It’s not an exaggeration to call the whole region a mini Yellowstone. There are hot springs, fumaroles, earthquakes, strange yellow lakes, volcanic domes: all signs of geologic forces still at work beneath the surface. It’s also breathtakingly beautiful. I wrote about the caldera a while back, but decided to flesh it out with more detail should people want to visit and see some of the fascinating sites for themselves. The caldera and the surrounding landscape remain one of my favorite places to explore in California. Every visit reveals something new.

Driving up Highway 395 toward Mammoth Lakes is one of the most breathtaking road trips in California. The highway winds through the jagged Eastern Sierra, offering mind-blowing views of snow-caked peaks, alpine meadows that are especially green right now, and vast chaparral plains. But beneath the landscape lies a hidden danger: heat and magma that power an ancient volcano that once shook the earth. Evidence of that past is everywhere and much of it can be easily experienced in a day’s drive around the region.

The Long Valley Caldera in eastern California is an extraordinary geological feature, spanning about 20 miles in length and 11 miles in width. It owes its existence to one of the most dramatic volcanic events in Earth’s history, a super-eruption that occurred approximately 760,000 years ago. This event, known as the Bishop Tuff eruption, ejected an estimated 150 cubic miles of molten rock and ash into the atmosphere, far surpassing the 1980 eruption of Mount St. Helens, which released just 0.3 cubic miles of material. The magnitude of the Bishop Tuff eruption resulted in the collapse of the ground above the magma chamber, creating a massive depression known as a caldera (Yellowstone has one, too, that’s larger.). The eruption was the largest volcanic event in the last million years of North American history.

The caldera sits just a few miles from one of the nation’s most popular ski towns, Mammoth Lakes. Geothermal activity is visible everywhere. Just driving up 395 from LA, you can spy huge piles of basalt from eruptions over the millennia. Just before Mammoth, steam rises from various hot spots where water has been super-heated by magma beneath the surface. This activity has made the caldera a hub for geothermal energy production. The Casa Diablo thermal power plant utilizes the subterranean heat to generate electricity, producing enough energy to power about 36,000 homes.

The surface of the caldera, indeed much of the region, is defined by the Bishop Tuff, a layer of welded volcanic ash that speaks to the eruption’s intensity and the pyroclastic flows that reshaped the landscape. Pyroclastic flows are fast-moving, hot clouds of gas and volcanic material that can destroy everything in their path. Often they are considered more dangerous than the lava that pours out of an erupting volcano. For example, pyroclastic flows killed far more people at Pompeii than lava, as the 79 AD eruption of Mount Vesuvius unleashed fast-moving clouds of superheated gas, ash, and volcanic debris that raced down the slopes at over 100 mph. Those waves of burning material reached temperatures above 1,000°F, instantly asphyxiating and incinerating thousands.

But where there is heat, there is often life. Geothermal features at the Long Valley Caldera commonly support microbial communities of thermophilic bacteria and algae, which thrive in the caldera’s hot springs and fumaroles. Walking around the caldera, your feet often crunch over dense dry mats of bacteria, giving the place a moonscape feeling. Scientists are just beginning to understand how similar bacteria live and thrive in deep ocean vent systems.

Around the caldera are many different features that also tell the story of the region’s continuing volcanic activity. Just to the north, the Mono-Inyo Craters can be visited after a short hike. This small volcanic chain was created by eruptions as recently as about 600 years ago.

Then, there is Horseshoe Lake, reached by car, town trolley, or a wonderful, if strenuous, bike ride. Here, clouds of carbon dioxide continuously seep from the ground, suffocating tree roots and causing a vast die-off of trees. The gas is invisible and odorless, and in high concentrations can displace oxygen, leading to unconsciousness or even death. Many people still swim in the lake during the summer, often just steps from signs describing the hazard. A few people have died or gotten sick up there, but really the key is to stay away from the deeper depressions in the area.

In 1980, a series of magnitude 6 earthquakes occurred along the caldera’s southern margin, drawing the attention of volcanologists from USGS. The earthquakes were accompanied by noticeable uplift in the caldera’s floor, a sign of magma movement beneath the surface. Since the 1980 unrest, parts of the dome have risen by more than 30 inches (about 80 centimeters), making Long Valley one of the most closely watched volcanic systems in the United States. The uplift can still be seen while driving into Mammoth Lakes, where a broad so-called resurgent dome rises from the caldera floor on the right-hand side of the valley.

The seismic unrest was significant enough that local officials and emergency planners began developed evacuation plans and routes for Mammoth Lakes in the event that volcanic activity intensified. In an interesting bit of local rebranding, the road was originally known as the Mammoth Escape Route, but after Mammoth-area businesses and landowners called out the alarming name, it was renamed the Mammoth Scenic Loop, which is what can be seen on signs today.

While there is currently no indication of an imminent eruption, the area is closely monitored by the United States Geological Survey (USGS).

A bit further out, but part of the same geologic phenomena, you can find Mono Lake, an easy drive from Mammoth. This place is also other-worldly, with its famous tufa tours rising from the still, greenish waters of the lake. They formed when calcium-rich springs, fed by groundwater moving through the area's volcanic rocks, mixed with the lake's alkaline water. The towers made their way into popular culture when Pink Floyd used a photograph of a guy diving into Mono Lake—the water completely still around him—for their Wish You Were Here album.

Of course, there are still other dangers to all this volcanic activity, right at Mammoth Mountain itself, which technically is a volcano. On April 6, 2006, three members of the Mammoth Mountain ski patrol tragically lost their lives after falling into a volcanic fumarole near the summit. They were conducting safety operations to secure a snow-covered geothermal vent after a major snowfall. If you’ve ever skied Mammoth before, there is a distinct sulphurous smell around the Christmas Bowl ski run at Chair 3 near McCoy Station.

I love exploring this region in California because it’s not only unparalleled in beauty but also geologic mystery. There is no place in California quite like the Eastern Sierra, and you can get to most places from paved roads, although some of the more interesting spots do require a four-wheel-drive vehicle. You see lots of Subarus up there.

What makes the region so special is that world-class science and tourism coexist side by side. You can spend the morning hiking through spectacular landscapes, then discover that the mountains, lakes, hot springs, and strange rock formations around you are all a part of California’s fascinating geology.

For thousands of years, the moon has quietly tugged at California’s coastline.

Its gravitational pull raises and lowers the Pacific twice a day, creating the tides that surfers and beachgoers know so well. In this way, the rhythms of the moon are also the rhythms of the earth. But tucked within those familiar rhythms is a much longer cycle, one that takes nearly 19 years to complete.

Scientists call it the lunar nodal cycle.

Most Californians have never heard of it. Yet it may help shape some of the state’s biggest environmental challenges of the coming decade: coastal flooding and erosion.

In 2021, researchers from NASA’s Jet Propulsion Laboratory, the University of Hawaiʻi and NOAA published a study warning that coastal flooding could increase dramatically during the mid-2030s as this natural lunar cycle begins amplifying tides just as rising seas push the ocean to higher levels. Combined, they could push many coastlines past critical flooding thresholds with increasing regularity.

“They’re getting awfully close to the brim in coastal communities due to decades of sea level rise,” William V. Sweet, an oceanographer with the National Oceanic and Atmospheric Administration and one of the paper’s authors, told the New York Times.

All of this may come as a surprise to many people living near the coast, but scientists warn that parts of California could be especially vulnerable. Places that today flood only during the highest king tides may find themselves dealing with water on streets, trails, parking lots, and marshes far more often. In some communities, flooding could occur every few days during particularly vulnerable months, not because of storms, but simply because the tide came in.

There’s a climate change angle to this, and that’s the major driver here, but it’s the lunar nodal cycle that adds a new potentially damaging dimension. The moon itself is not changing. Instead, the plane of the moon’s orbit slowly wobbles over an 18.6-year cycle. Astronomers have known about this phenomenon since the 18th century, but only recently have scientists begun to understand how it may interact with rising sea levels to amplify coastal flooding in places like California. The outlook is not especially encouraging.

As NASA put it in a published report in 2021: “There’s nothing new or dangerous about the wobble; it was first reported in 1728. What’s new is how one of the wobble’s effects on the moon’s gravitational pull — the main cause of Earth’s tides — will combine with rising sea levels resulting from the planet’s warming.”

The sun plays a role here, too. Along with the moon, it helps drive Earth’s tides. Twice each month, the sun, Earth, and moon align to produce the highest tides of the lunar cycle. Normally, that’s not a major concern. But when those alignments coincide with the amplifying phase of the lunar nodal cycle and a higher ocean, the result can be enough to push some coastal areas past flooding thresholds.

Ben Hamlington, who co-wrote the paper and runs the Sea Level Change Team at JPL, said the findings offer an important planning tool for coastal communities. While cities often focus on preparing for rare disasters like tsunamis and storm surge, the more immediate, but quiet challenge may be a steady increase in disruptive high-tide flooding.

Future sea level rise is already baked into the climate system. Sea level along California's coast has risen roughly 8 inches over the past century, and scientists project additional rise in the decades ahead. As oceans continue to climb, the next high phase of the lunar nodal cycle will give tides an extra boost. The increase may only amount to a few inches in many locations, but when coastal communities are already operating near flooding thresholds, a few inches can make all the difference.

What exactly is happening?

Hamlington compares the lunar nodal cycle to a coin spinning on its edge (scientists also use the term “the Regression of Lunar Nodes”). As the coin slows, it develops a subtle wobble. I didn’t find this explanation very satisfying. I think this is a situation where words don’t quite suffice and a visual explanation helps quite a bit. Here’s a video where Professor Kevin Horsburgh of the National Oceanography Centre uses a soccer ball and a tennis ball to demonstrate how the moon's tilted orbit slowly changes orientation over the 18.6-year cycle.

The moon itself isn’t wobbling, however. Instead, the tilt of the moon’s orbit slowly shifts direction over time, completing a full cycle every 18.6 years. That gradual change alters the way the moon’s gravity affects Earth’s tides, causing them to be slightly amplified during some decades and slightly suppressed during others. We’re soon entering the amplification period. It’s a small effect, but one that could become much more important as rising seas push coastal communities closer to flooding thresholds.

The lunar nodal cycle has been going on for thousands of years. Historically, it was little more than a scientific curiosity. Today, however, the Pacific Ocean is slightly different than where it was decades ago. So, tides that once stopped just short of roads, wetlands, and sea walls may soon spill over them. And it’s coming relatively soon, likely as early as the mid 2030s.

For California, the impacts are likely to be somewhat localized. The state’s dramatic cliffs protect many stretches of coast. But low-lying areas are increasingly vulnerable. San Francisco Bay may be particularly impacted. Large stretches of the bay shoreline sit only a few feet above the present sea level. Wetlands, airports, highways, wastewater treatment plants and neighborhoods already deal with periodic flooding during king tides. According to this report, things could get worse in these vulnerable areas.

Southern California has its own vulnerable places. Beach communities, coastal lagoons, harbor infrastructure, wetlands, and transportation corridors may all face increasing pressure from higher water levels. Even places that remain dry can experience problems when seawater backs up drainage systems and reduces their ability to handle runoff.

One of the more surprising findings of the research is that future flooding may not be evenly distributed throughout the year. Instead, flood days could cluster together into what the researchers called “extreme months.” And so imagine a coastal community dealing not with a handful of nuisance flooding events spread throughout the year, but with flooding every few days for weeks at a time.

The researchers’ hope is that the information will be of use to planners and policy-makers in coastal areas. “Understanding that all your events are clustered in a particular month, or you might have more severe flooding in the second half of a year than the first – that’s useful information,” says Hamlington.

The good news is that none of this is a surprise. Scientists know the lunar cycle is coming, and coastal communities have time to prepare. Last year, I read Rosanna Xia’s excellent book California Against the Sea, which explores the difficult choices California faces as rising seas inch farther inland. Across the state, communities are experimenting with solutions ranging like wetland restoration and building seawalls, etc. Unfortunately, in some places like Ocean Beach and Pacifica it seems the most practical long-term option may be managed retreat: moving roads, buildings, and other development away from vulnerable, crumbling shorelines.

All of this is already unfolding. California's coastline is changing, and communities are increasingly being forced to adapt. The amplifying phase of the lunar nodal cycle expected in the 2030s is obviously not the root cause these problems, but it could briefly make them worse. As higher tides combine with higher seas, some coastal areas may find themselves facing a period of elevated flooding risk and greater uncertainty.

As Philip R. Thompson, the lead author of the study and the director of the Sea Level Center at the University of Hawaii said to the Times, “If we know what’s going on, then we shouldn’t be complacent. It’s important to realize that at the mid-2030s point, where the switch flips and the natural cycle seems to amplify the rate of sea level rise, then we are going to see a rapid change.”

So, let’s get ready.

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It’s one of the strangest and coolest wildlife stories in Southern California: green sea turtles are living and thriving at the mouth of the San Gabriel River. A big, urban, ugly concrete river in the middle of LA. Well, or Orange County. Or both, since the river is the boundary between the two counties.

And so I went and saw them. I found the spot on Google Maps after seeing a post on Instagram put out by the Aquarium of the Pacific. I parked near the 405 freeway, slipped through a hole in a fence, and climbed up a steep embankment where the San Gabriel River flows lazily through a concrete channel.

And there they were.

Sea turtles. Eastern Pacific green sea turtles, to be exact. Probably twenty of them. Several were huge, maybe two hundred pounds or more. Others were smaller. Perhaps juveniles. Swimming and feeding beneath bridges, beside power plants, and inside one of the most engineered waterways in California.

Of course, I filmed them and hung around for a while, feeling both astonished by the sight and slightly embarrassed that I had never come to this spot before. A family of five people, locals, had come down, and the children whooped and giggled as they followed one particularly large turtle as it slowly paddled its way upriver.

They are majestic and beautiful, if a bit cartoonish. Swimming against the current, which also carries trash and other detritus, they use their flippers like giant oars and only progress a foot or two with each stroke. Every few minutes, one would raise its head above the water and take a quick sip of air. On a few occasions, one would glance quickly at me before going back under.

What ancient-looking creatures! A sea turtle’s face has a segmented, reptilian look, like smooth, perfectly laid stones. Its eyes are blackish, but curious. The shell is also fantastically geometric, made up of large polygonal plates called scutes. Scutes are made of keratin, the same material found in human fingernails and hair. Beneath the scutes is the actual bone structure of the shell.

I wanted to know more, so I started digging through papers and reports, and when I still wasn’t satisfied, I called the Aquarium of the Pacific in Long Beach. It turns out the aquarium has been directly involved in the monitoring, conservation, rescue, and rehabilitation of these turtles for years. I spoke to Cassandra Davis, director of volunteer services for the Aquarium of the Pacific, who has been involved with the Aquarium’s turtle program for several years. The first thing I asked is: why are they here?

“It really is shocking. It’s surprising, magical, and surreal all at the same time,” says Davis. It turns out these animals travel thousands of miles across the Pacific to find refuge in one of the last places you’d expect: the concrete waterways of Los Angeles. “Green sea turtles are so good at navigation that they can find tiny islands in the middle of the Pacific that up until very recent modern technology, even humans couldn’t reliably find for the most part,” she says.

Far out at sea, the turtles migrate between feeding grounds and nesting beaches, with females returning to sandy beaches in places like Mexico to lay eggs. Weeks later, hatchlings emerge from the sand (I’ve personally seen this once) and scramble toward the ocean, beginning a journey that, for some, may eventually lead all the way to the San Gabriel River.

The turtles here are considered the northernmost resident population of green sea turtles in the eastern Pacific Ocean. Scientists once thought that distinction belonged to turtles farther south near San Diego. Researchers estimate there could be well over a hundred turtles that call the San Gabriel River and the Cerritos Wetlands home.

But why here?

According to Davis, part of the answer is warmth. Green sea turtles are reptiles, and they tend to seek out a thermal refuge. Here at the outflow of the San Gabriel River, the waters are shallow and therefore keep relatively warm. “The sun shines and the water comes out at a nice spa temperature,” she says. Also, several nearby power plants have an impact as well. “They discharge warm water and that heats up that area of of the river.”

But the river also provides food and shelter. The turtles gather around the Los Cerritos Wetlands, where there is plenty of algae and aquatic vegetation, their favorite meal. I watched one grab a large chunk of green slime as it moved down river and gulped it down with one or two swallows.

We’ve known about the turtles for decades, but recently researchers, volunteers, and conservation groups have been working to better understand and protect them. The National Oceanic and Atmospheric Administration (NOAA) is deeply involved in sea turtle conservation in Southern California, including the San Gabriel River population.

According to Davis, the turtles face threats from fishing line, hooks, pollution, habitat loss, and boat strikes. In March 2025, a turtle nicknamed Porkchop was rescued after becoming tangled in fishing line. It’s flipper had been cut deeply by the line, and after nearly a year of rehabilitation, including amputation of the damaged flipper, the Aquarium of the Pacific released it back into the San Gabriel River in February 2026.

Some turtles here are also fitted with tracking tags so scientists can better understand their movements and behavior. But satellite tags are expensive, and the turtles have a tendency to get rid of them, so some are fitted instead with small metal tags embedded with a microchip so they can be easily scanned and identified. “And then the latest method of tracking is we’re using photo ID. We’re using identification of the face itself of the sea turtles,” says Davis.

Though they are still considered threatened, green sea turtle numbers are rising in many parts of the world thanks to decades of conservation efforts and habitat restoration. Davis says researchers are seeing encouraging signs in Southern California as well.

“We are really, really hopeful for an animal like the green sea turtle,” she says.

And maybe that’s what makes this story so remarkable: a threatened sea turtle thriving in an urban river in Los Angeles.

As Davis puts it, “It is so amazing to live in a time when we get to see these recovery stories starting to play out.”

Two years ago, I did the climb from the valley floor to the top of Yosemite Falls, a gain of some 2,800 feet in 7 miles. It was one of the most exhausting things I’ve ever done, but the views from up on those granite heights are magnificent and make all the work worthwhile.

Few places are as geologically mind-blowing as Yosemite. You’ve got epic scenery in every direction. Stunning waterfalls and rivers. Lots of animal life. And of course, those jaw-dropping granite walls that stretch thousands of feet above the valley floor: El Capitan and Half Dome.

But here’s something most people probably don’t know: those two world-famous cliffs are actively falling apart. Slowly. Constantly. In giant sheets that weigh hundreds of tons.

The process is called exfoliation, and it’s one of the more bizarre things geology does. Donald Prothero, the author of California’s Amazing Geology, defines it as “the peeling off of sheets of rock as they weather on the surface.” But that description, although you can picture it, doesn’t quite capture what’s actually going on. Or the magnitude of it. Or the danger. The fact is, some of the most massive, durable-looking rock formations on the planet are in a continuous state of so-called “pressure release”, shedding their outer layers in curved slabs the size of houses.

But why?

The granite that makes up Yosemite formed during the age of dinosaurs. We did a whole piece on the creation of the Sierra Batholith and its unimaginable immensity and mass. The enormous granite bodies that underly most of the Sierra range were part of one of the most rapid periods of continental crust assembly on record. The rock that would eventually become Half Dome and El Capitan spent tens of millions of years buried under tremendous pressure, with miles of material stacked above it. Erosion over time exposed the granite. And glaciers carved them into the gargantuan slabs we see today.

But granite is not forgiving. It doesn’t flex. It cracks.

Exfoliation happens through pressure release. In other words, the rocks form under great pressure beneath the surface, but once they rise into the sky and erosion reveals them, the built-up pressure dissipates, and the rock expands and cracks along what geologists call planes or zones of weakness. The result is a series of curved fractures that form parallel to the surface, concentric sheets that peel away layer by layer. As Prothero puts it, “they form curved fractures and the layers peel off in a manner that is similar to the peeling off of the layers of an onion.”

This is why formations like Half Dome, North Dome, and Liberty Cap look sculpted rather than jagged. Prothero writes that this onionskin peeling “is the predominant form of weathering and breakdown operating in the High Sierras today.”

Glaciers were still essential to shaping Yosemite. During the Ice Ages, massive rivers of ice carved Yosemite Valley into its dramatic U-shape. They steepened the cliffs and polished exposed granite surfaces. But the domed geometry of formations like Half Dome is thought to result mainly from exfoliation and pressure release, with glaciers later refining and exposing them.

What accelerates the process is frost wedging. Water seeps into the hairline cracks created by pressure release, then freezes overnight and expands by nearly ten percent, forcing the crack wider. It thaws during the day, seeps deeper, then freezes again. It’s this cycle in the Sierra, where temperatures repeatedly rise and fall rapidly, that cause massive cracks in places that started as a microscopic fracture. Eventually, a sheet of rock that had been clinging to the cliff face for thousands of years simply lets go and crashes to the ground.

And in a place like Yosemite that attracts millions of visitors, that can be very dangerous. Even deadly.

On September 27, 2017, a slab of granite roughly the size of a 13-story apartment building broke loose from El Capitan’s east face, 650 feet above the valley floor. Andrew Foster, 32, from Cardiff, Wales, and his wife Lucy, 28, were standing on a pile of rocks at the base of the wall, picking up trash. Andrew had just quit his job at Patagonia Europe. He and Lucy had taken the trip to celebrate their first wedding anniversary. When Andrew heard the crack and saw what was coming, he threw himself on top of his wife. Lucy later told his aunt: “Andrew saved my life. He dived on top of me as soon as he could see what was going to happen.”

Andrew Foster died. Lucy was airlifted out with a punctured lung.

The next day, a second fall came from the exact same location. It was significantly larger than the first. The dust cloud it sent into the valley could be seen for miles. Ken Yager, who has lived near the park for decades and climbed El Capitan many times, watched it from his car. “I’ve probably only witnessed clouds that big maybe six times,” he told the Times.

That evening, geologists worked the face of El Capitan by helicopter and lidar scanner, mapping the scar and modeling how the rock had broken away. Both events were classic exfoliation failures: rock sheets tens of meters tall and wide, typically less than a meter thick, peeling away those planes of weakness, those fractures that run parallel to the rock face, built up over thousands of years of thermal stress and freeze-thaw cycling.

Rockfalls in Yosemite are common; the park documents up to 80 events per year, and a 2013 USGS report catalogued 925 slope movements between 1857 and 2011, killing 15 people and injuring at least 85 over that span. El Capitan’s southeast face alone has experienced 57 documented rockfalls over the past 40 years. Most are small. Some are not.

The cliffs of Yosemite look like the quintessence of permanence. They have been there for millions of years. People have been standing at their base, camping, climbing, and taking photographs for over a century. Theodore Roosevelt and John Muir spent time near the granite behemoths. But nature does what it wants, and we are more or less oblivious to the ongoing, slow geologic processes that are hard to fathom in this age of immediate gratification. And, of course, the processes that shaped them doesn’t stop. The pressure that was locked into that granite 100 million years ago is still being released, still working its way outward through the rock, still finding new cracks to open.

What fascinates me most is how these plants survive. Succulents have evolved remarkable strategies to endure punishing heat and prolonged drought. Some store water in leaves, others in swollen stems or roots. Many open their pores only at night, conserving moisture during the hottest hours of the day. The more I learned about them, the more I wanted to know.

That fascination eventually led me to The Huntington, just a short drive from my home. (For years many people knew it as the Huntington Library, Art Museum, and Botanical Gardens, but the institution recently revamped its branding and is now known simply as The Huntington.) Over the years, I’ve spent countless hours wandering its Desert Garden, one of the most important succulent collections in the world. It’s a very special place.

Recently, while reporting this story and video there with my colleague Tod Mesirow, I met John Trager, the longtime curator of the Desert Garden. Trager has spent more than four decades studying and caring for these plants, and speaking with him helped me understand why succulents inspire such devotion among collectors and gardeners around the world

“Perhaps the thing that stands out the most about succulents is the unusual combination of form and flowers,” Trager told me. “You have these funny globular things with spines, yet they produce flowers that look delicate and familiar, like something that would attract a bee.”

The Desert Garden spans over 10 acres, and is one of the oldest and largest collections of cacti and succulents in the world, with over 2,000 species on display. Established in 1919 by Henry E. Huntington, it showcases plants from arid regions around the world, including unique specimens from North and South America, Africa, and Madagascar. Of course, most succulents are not native to California, and a few succulent species have become invasive in California (some folks I know HATE ice plant), but most are non-native ornamentals that have become deeply embedded into Southern California gardens and homes.

Succulents are not a single plant family, but a form of adaptation. “Basically it’s water-storing tissue and the ability to survive prolonged periods of drought,” says Trager. For example, many species also use a specialized form of photosynthesis known as CAM metabolism, opening their pores at night instead of during the heat of the day to conserve water.

Unfortunately, the beauty and rarity that make these plants so fascinating have also made them targets.

Plant theft, especially of rare and exotic succulents, has become a significant concern for botanical gardens, nurseries, and natural landscapes worldwide. The growing popularity of certain species among collectors and hobbyists has fueled a thriving black market, now worth billions of dollars globally.

The Huntington is one of the institutions on the front lines of this battle against plant theft. At the upper end of the desert garden, a locked greenhouse shelters around 3,000 vulnerable succulents that are highly sensitive to excessive water or freezing temperatures. Many would-be thieves would love to get their hands on some of these specimens. Trager took us on a private tour of the greenhouse and we interviewed him inside for the video above. Trager also spoke candidly about the growing problem of plant theft at The Huntington and the challenge of protecting rare specimens that can fetch high prices among collectors.

“People don’t think of it as theft when they’re just taking a little piece here or there,” Trager told us. “But it’s most annoying, of course, when they take an entire plant, dig it out of the ground. Sometimes those are not that easy to replace.”

Trager reported that the garden recently suffered a significant theft involving a species of succulent called echeveria , a large genus of flowering plants from the Crassulaceae family, native to the semi-desert regions of Central America, Mexico, and northwestern South America. The Huntington had three documented specimens, each with known provenance, making them especially valuable for scientific research. Two of the three specimens were stolen.

“When the second one was taken, we’re left with a lone individual that can’t be self-pollinated and with no chance of being able to propagate that documented collection for perpetuity,” laments Trager.

Part of the institution’s response has been to make rare succulents more available through ethical propagation programs. “One of the nice things about most succulents is that they’re easy to propagate,” Trager said. “So we do propagate and sell plants. We make them readily available to the public. We prefer that you buy the ones that we propagated for you rather than take them from the garden.”

As one of the country’s leading institutions dedicated to the cultivation and conservation of succulents, The Huntington and Trager feel a responsibility not only to protect these plants, but also to help ensure their survival through education, research, and propagation.

“The purpose is to distribute new and interesting plants to collectors, institutions, researchers, et cetera, anyone who’s interested,” says Trager. “A lot of them are increasingly endangered, so there’s a conservation component, but we’re interested in both wild species and horticultural entities. So both of them are within our purview.”

The Covid pandemic led to a rise in interest in indoor gardening and houseplants, including succulents, as people spent more time at home and looked for ways to enhance their living spaces and alleviate stress (raises hand). Succulents, known for their low-maintenance care and unique aesthetic appeal, became particularly popular.

Trager points out that since the program began at the Huntington, the garden has distributed over 1,480 species and cultivars, totaling approximately 74,000 plants. Given that many of these plants are endangered, the program functions as a kind of Noah’s Ark, protecting these rare species and helping to ensure their survival for the future.

For me, though, the appeal of succulents goes beyond conservation. I still find myself wandering the Desert Garden at The Huntington just to look at them. The bizarre geometry (Fibonacci spirals!). The crazy spines. Even after years of visiting, many of the plants still seem alien to me, cool reminders of just how inventive evolution can be.

At the California State University Long Beach Shark Lab, which is landlocked though just a short drive from the beach, the vibe is part messy garage, part frontier science. A kiddie-pool-sized tank circles with small sharks and stingrays. Along the walls, rows of dried jaws hang open, rows of razor-sharp teeth, straight out of Jaws. On a nearby table, syringe-sized tagging devices sit ready, wired and waiting.

This is one of the country’s leading centers for studying elasmobranchs, the ancient group of cartilaginous fish that includes sharks, rays, skates, and chimaeras. And its director, Chris Lowe, has spent decades trying to answer a deceptively simple question: what are these animals actually doing just off California’s beaches, and what does that mean for the millions of people who share the water with them?

The answer starts with a shift in perspective.

California is not just a place where sharks pass through; it’s a core part of their world. “We’re seeing more along our coast than we’ve ever seen before,” Lowe says. In Southern California especially, juvenile white sharks gather in what scientists now recognize as busy nursery habitats, shallow, warm, food-rich zones close to shore.

And those sharks are not rare.

“I can tell people on any given day I could probably take them out and show them a white shark,” Lowe says. Twenty-five years ago, he would have laughed at that idea.

What changed is not just awareness, but the ocean itself. Decades of conservation, including protections that began in 1994, when the state made it illegal to target or land great white sharks, effectively gave them full protection in state waters. This has allowed white shark populations to recover. At the same time, their prey has rebounded. Also, thanks in part to the Marine Mammal Protection Act, “There are now more California sea lions on the planet than there may have ever been,” Lowe notes. Add in abundant stingrays, a favorite food for young sharks, and the result is a coastline that looks more like it did a century ago.

More sharks. More people. And the same water.

And yet the risks remain remarkably low.

Since 1950, California has recorded roughly 130 unprovoked shark bites, with just 10 fatalities, according to the International Shark Attack File and the California Department of Fish and Wildlife. In a state where tens of millions of people enter the ocean every year, that’s very small. But, still, it is non-zero.

“When you consider how many people use the ocean on a daily basis, the likelihood of being bitten by a shark is so infinitesimally small that it almost seems crazy to worry about,” Lowe says.

That doesn’t mean bites don’t happen. They do. But they are rare, and increasingly better understood, thanks to the Shark Lab. Even as shark numbers rise, the rate of attacks does not rise proportionally. “You put more people in the water with more sharks, you would expect shark bites on people to go up, but we’re not really seeing that,” says Lowe.

Why sharks bite people at all is still an open question. It could be mistaken identity, a swimmer silhouetted like a seal. It could be exploratory, a test bite. Or defensive, the shark feels threatened in some way. “As best we can tell those are probably accidents. The rate at which they’re making mistakes is incredibly low,” says Lowe.

In other words, sharks are not hunting us. If anything, they’re ignoring us.

“We have hours of footage of people in the water, sharks swimming right by them, sometimes right underneath them, and completely ignoring them,” Lowe says, pointing to drone footage of a sleek silhouette passing astonishingly close to a surfer.

That gap between perception and reality is the foundation of the Shark Lab’s work. The team tags sharks with acoustic transmitters, tracks them across hundreds of miles, and feeds real-time data to lifeguards. The result is a system where beaches are no longer closed simply because a shark is nearby. In many cases, sharks are present every day.

Instagram accounts like that of Carlos Gauna, also known as Malibu Artist, have built large followings posting drone footage of Southern California beaches where juvenile white sharks cruise just beyond the break, weaving through crowds of surfers and swimmers who have no idea they’re there. Despite documenting dozens, even hundreds of these close encounters, he has yet to capture a single attack. Of course, if he ever does, that’ll be pretty nuts.

But as I wrote a few weeks ago, perhaps the fear over great white sharks is not only overblown, but misplaced. If you measure danger not by fear but by injuries, even mild ones, the most consequential animal in Southern California surf isn’t a shark. It’s a stingray. As I wrote, it is possible, if not likely, that Southern California, Seal Beach in particular, is the stingray capital of the world.

“We estimate that there are at least 10,000 people treated for stingray injuries per year in Southern California alone,” Lowe says. That number dwarfs shark incidents. The irony is that sharks may actually be part of the solution.

“Baby white sharks, their favorite things to eat are what we call stingray pancakes,” Lowe says.

In other words, you are probably not shark food, but it is shark food - stingrays - that are mostly hurting us, and sharks may be a means by which we significantly reduce the stingray population: “When there are a lot of white sharks off your beach, believe it or not, they’re keeping you safer, because they’re eating the stingrays that are far more likely to injure people than the sharks are themselves”.

In a way, it’s a classic ecological loop. Predators return and systems rebalance. Which brings us back to what’s coming: A sharky summer. Yes, Lowe says we’re likely to see more sharks this year. Warmer waters, rising populations, and lots of beachgoers. But as Lowe says, let’s not panic. Feel free to return to the water. Ignore the da-dum da dum music playing in your head.

Because the reality is this: the water off California has always been a shared space with these animals, and for a long time, we tried to shove sharks out of it. Now they’re coming back.

“We have to learn to share the waves with them again,” Lowe says.

They were here first.

Editor’s note: The peak migration period at Bear Divide in the San Gabriel Mountains typically occurs between April 10 and May 20, making this the optimal time to visit. During these weeks, species such as western tanagers, lazuli buntings, and various warblers can be observed in impressive numbers. Early morning visits are particularly rewarding, as the majority of migratory activity happens shortly after sunrise.

You can follow recorded sightings for 2026 here.

“Personally, I really think it’s one of the best birding spots in the world,” Ryan Terrill, science director at the Klamath Bird Observatory.

Within a 45 minute drive from the urban chaos of downtown Los Angeles, lies a natural, ornithological marvel: Bear Divide, a vital corridor for the annual migration of numerous bird species. Every year — roughly between March 15 and June 15, with peak migration between April 10 and May 20 — thousands of birds funnel through the narrow pass. The divide is a small dip in the otherwise impregnable San Gabriel mountains, allowing birds in the midst of their migration to pass through safely at relatively low altitudes. This area is not just a haven for bird enthusiasts but also a critical research site, especially for the team from the Moore Lab of Zoology at Occidental College, who have been delving into the intricacies of these migratory patterns.

The Moore Lab of Zoology is renowned for its extensive bird specimen collection, one of the largest of its kind in the world for Mexican birds. They also hold several taxidermied specimens of the passenger pigeon, once among the most abundant birds on Earth before its rapid extinction in the early 20th century.

Bear Divide is strategically positioned along the Pacific Flyway, a significant north-south migratory route used by birds traveling between Alaska and Patagonia. The geographical features of the San Gabriels provide an ideal resting and feeding ground for these birds, making Bear Divide a crucial stopover during their long journeys. It’s this unique combination of location and topography that makes Bear Divide a fascinating part of global avian migration.

The discovery of Bear Divide was a lucky happenstance. A bird researcher was conducting overnight monitoring in the spring of 2016, and when morning came, he noticed legions of small songbirds whizzing past his monitoring spot. His report caught the attention of postdoc bird scientist Ryan Terrill, at Moore Lab at the time, and he began an effort to monitor the birds. Terrill and his team would ultimately record as many as 20,000 birds in a single morning.

“It really is overwhelming to stand on the road and have 5,000 birds of 80 species fly by your knees in a morning,” Terrill said. The effort has continued to this day with startling results. Terrill has since left and is now the science director at the Klamath Bird Observatory.

“In 2023 we counted 53,511 birds of 140 species from February to May,” said John McCormack, a professor of biology and the Director and Curator of the Moore Laboratory of Zoology. “And of course, we missed many thousands more because most travel at night. It’s easy to say that there are hundreds of thousands of birds passing through Bear Divide.”

As many as 13,000 western tanagers, lazuli buntings, chipping sparrows, hermit warblers, orioles, grosbeaks and warblers pass through Bear Divide on a single day. Why they do so, is not entirely understood. The unusual topography of Bear Divide essentially serves as a funnel for the migrating birds, with many of them shooting through the gap just a meter or two above ground.

“Personally, I really think it’s one of the best birding spots in the world,” Terrill told the LA Times.

McCormack says that the “ultimate goal is to better understand the Pacific Flyway and how it’s used, especially by small terrestrial birds. Little is known about their movements because they are hard to see and usually travel at night.”

Because many of the species sighted at Bear Divide are in steep decline. The lab says that year-to-year counts will help set a baseline for future trends that can be associated with weather, climate, and urbanization. “Tracking individual birds will give granular knowledge on how migratory birds use the landscape, which helps individuals and homeowners create corridors for them to travel,” says McCormack.

The best time to catch the show at Bear Divide is late winter and early spring. McCormack says cliff swallows and Lawrence’s goldfinch are some of the early movers in March, and that by May, streaking by are yellow warblers, sunset-faced western tanagers, and bright blue lazuli buntings.

“There is so much we still don’t know about these birds and their world,” Lauren Hill, the site’s lead bird bander, told the Los Angeles Times. “For example, no one knows where they were before showing up here after sunrise.”

The team is counting birds in order to establish a baseline of the populations coming through Bear Divide so they can understand how much we are changing the environment and what effect that may have on bird populations, many of which are in severe decline.

Their research spans a variety of topics, including how climate change is impacting migration routes and the effects of urbanization on bird populations. The lab has recently begun a program to put satellite trackers on birds at Bear Divide to follow individual birds, providing deep insight into their migration and resting patterns.

One of the most fascinating aspects of Bear Divide is the sheer variety of bird species it attracts. From the diminutive hummingbirds to the impressive birds of prey, each species adds a unique dimension to the study of migration. The Moore lab’s findings have shed light on the varied responses of different species to environmental changes, offering a glimpse into the broader ecological shifts occurring across the globe.

One particularly interesting result of the Moore Lab’s study at Bear Divide suggests that the peak of a particular species’ migration is correlated with the latitude of its breeding site. Species that breed at higher latitudes migrated through Bear Divide at later dates. It’s also unusual in the West for species to migrate during the day. Most species of birds using the Pacific Flyway are known to migrate at night.

In addition to its scientific contributions, the Moore lab is also known for its involvement in citizen science. Collaborating with local birdwatchers and volunteers, the lab extends its research capabilities and cultivates a community actively engaged in bird conservation. This collaborative approach not only expands the reach of their research but also brings people directly into the work of conservation.

Bear Divide is on public land, so anyone with a legitimate research project can get permission to work there. UCLA graduate student Kelsey Reckling, who has worked as a counter at Bear Divide since the beginning, led the counting efforts last Spring to understand changes in numbers of birds and species across years. Cal State L.A. graduate student Lauren Hill leads the group of bird banders, who catch some of the birds and record data, attaching a lightweight metal band around one leg and releasing them. Her lab mate Tania Romero is putting small, lightweight tracking devices on yellow warblers, which send signals to a network of tracking (MOTUS) towers across the continent.

According to a 2019 study, nearly 3 billion breeding birds have been lost in North America and the European Union since 1970. That’s about 30% of the bird population in North America. The 2022 State of the Birds Report for the United States found that bird declines are continuing in almost every habitat, except wetlands. Protecting birds’ habitats, and migration routes and reducing mortality through conservation efforts are crucial to ensuring the survival of these magnificent creatures.

“What’s magical about Bear Divide is that it’s the first real place to see small, migrating birds at eye level in daylight hours,” says McCormack. “I don’t want to oversell it: it’s still a lot of small birds zinging by in a wide open place, and it takes a while to get good at identifying them. But by seeing them out there, struggling against the wind and the cold, but still making progress, it gives you a real sense of how amazing their journeys are--and how we shouldn’t make them harder if there’s anything we can do about it.”

Lately, with Artemis II swinging around the far side of the Moon and sending back stunning footage of an earthrise, space is kind of exciting again. Seeing Earth from that perspective reminds us what big, ambitious projects can do...recent NASA defunding notwithstanding (what a disaster).

But!

As I’ve written here before: while we look up, it’s also worth remembering to look down.

In the early days of the space race, that was the mindset as well. As the Gemini program was getting underway, building on the earlier Mercury program missions (“Godspeed, John Glenn”), there was a parallel effort to go the other way. Not into orbit, but deep down…into the ocean. The aspirations were similar: If humans could learn to live in space, maybe they could learn to live on the seafloor too.

For a brief window, we were serious about both. And there were even a few individuals who were part of the two programs: astronaut/aquanaut Scott Carpenter was one of them.

Unfortunately, while we managed to go to the moon on Apollo (and hopefully soon again with Artemis), the ocean effort stalled and never really came back. That story is largely forgotten now, but it’s interesting, and it has a very specific California angle. In fact, one of the most ambitious attempts to allow humans to live on the ocean floor took place just off San Diego, coincidentally, near the same stretch of sea where the Artemis astronauts recently splashed down to Earth decades later.

The project was called SEALAB II. Let’s get into it.

There were many reasons to try to live beneath the waves. The scientific potential was enormous, but so were the military applications. Aquanauts, as they were called, could work for hours at depth, something that was nearly impossible before.

There was a distinct national vibe for this kind of thing.

In 1963, John F. Kennedy told the National Academy of Sciences, “To a surprising extent, the sea has remained a mystery. We know less about the oceans at our feet than the sky above our heads.” He pushed Congress to invest in ocean research, warning that “knowledge of the oceans is more than a matter of curiosity. Our very survival may hinge upon it.” That remains true.

Living underwater may not seem as extreme as space, but it comes with its own set of problems. Breathing is the obvious one. We can’t inhale water. Then there’s pressure, which increases rapidly with depth and changes how the body functions. It has a tendency to crush things. Even shallow diving can cause problems. As a certified scuba diver, I’ve had several scary moments underwater in my lifetime. Further, deep water is cold, and water has a much higher thermal conductivity than air, so you lose heat much faster. Visibility is limited. And yes, there are living things down there that can kill you.

In other words, if humans were going to live underwater, there was a lot to figure out.

The effort started in 1964 with SEALAB I, launched by the U.S. Navy. Engineers built a pressurized habitat that could support a small crew for days at a time. In that first mission, four men lived for 9 days at a depth of about 192 feet off Bermuda. It proved the basic idea could work. Living at depth for days at a time changed what divers could see. Instead of brief visits, they became part of the environment. Marine life carried on around them. “You could see these animals doing things undisturbed. They sort of got used to us,” aquanaut Richard Grigg said after emerging from SEALAB I.

SEALAB I did some science, but it was mostly a proof-of-concept. It was time to ramp things up.

There’s kind of a crazy hero in all this who deserves mention, although I won’t go into too much detail about him because it would take pages, but he’s one of the more unusual figures in the history of ocean exploration. If you want the full story, Ben Hellwarth’s book Sealab: America’s Forgotten Quest to Live and Work on the Ocean Floor is excellent. I read it a few years ago, and a lot of what’s here comes from notes I took then.

That man was George Bond. Yes, Bond. George Bond.

Bond was a Navy doctor, but also a researcher, a diver, and one of the few people willing to rethink the fundamentals of how humans operate underwater. Bond saw a flaw in traditional diving. Divers spent hours decompressing near the surface for just minutes of work. His solution was saturation diving, which in many ways was still theoretical. But the basic idea is simple: keep divers at depth for days or weeks, then decompress once at the end.

And so, after the success of SEALAB I, the next step was clear. SEALAB II.

Off San Diego, the Navy significantly scaled up what had been accomplished near Bermuda, placing a larger habitat about 205 feet below the surface on a ledge along an undersea canyon in the murky waters off La Jolla. The uneven seabed left the structure slightly tilted, enough that loose objects would slide across the floor, prompting one aquanaut to nickname it the “Tilton’ Hilton.” But compared to the cramped design of SEALAB I, the new habitat felt almost luxurious, with larger sleeping and eating areas, a dedicated lab, and even a few unexpected flourishes, including an exterior shark cage and curtains on its 11 portholes.

Inside, small teams of aquanauts, usually three at a time, lived under pressure for weeks, breathing a helium-oxygen mix. This was the key to saturation diving, but it had not been thoroughly tested or proven over long periods of time.

As you likely know from high school chemistry class, the air we breathe is around 78 percent nitrogen. Under pressure, nitrogen from the air dissolves into the body’s tissues. Come up too quickly, and that nitrogen forms bubbles, causing severe pain or even death. It’s known as decompression sickness, or, simply, the bends.

Saturation diving reduces that risk by replacing most of the nitrogen with helium, allowing the body’s tissues to fully saturate at depth. Helium still dissolves under pressure, but it doesn’t have the same narcotic effects as nitrogen and moves through the body much more quickly, making it easier to manage during that single decompression.

And so, from August to October 1965, three teams of aquanauts, Navy divers and civilian scientists, each spent about 15 days living 205 feet below the surface off La Jolla. They carried out research on human physiology, ocean science, and underwater operations, even working with a trained porpoise named Tuffy to test the idea of animal-assisted rescue.

Aquanauts also tested tools, ran experiments, and proved that saturation diving was practical. The program also explored underwater construction and the limits of human endurance in isolation.

There were real risks. Gas mix errors, equipment failures, and the constant threat of decompression sickness or oxygen toxicity were always lurking. Even small mistakes could escalate quickly at that depth. The helium-oxygen mix itself created challenges, distorting voices and making communication harder.

There’s a great, hilarious even, recording of Scott Carpenter speaking from the seafloor with President Lyndon B. Johnson. Breathing a helium-oxygen mix, his voice comes through high and distorted, the same way your voice sounds funny when you inhale from a helium balloon, except that it lasted for the duration of the mission.

Here it is:

SEALAB II was, in many respects, a success. It showed that humans could live and work at depth for extended periods, proved the practicality of saturation diving, and led to new insights into human physiology and long-duration isolation. Briefly, it suggested a real future in which people might live and work routinely on the ocean floor.

It also set the stage for SEALAB III in 1969, conducted off San Clemente Island, which aimed to push the concept deeper, to more than 600 feet.

But it was not to be.

Almost immediately, SEALAB III ran into trouble. A leak contaminated the habitat’s breathing system, making it unsafe for a full crew. The Navy quickly sent divers down to investigate and repair the problem, but the risks at that depth were significantly higher than in SEALAB II. The habitat developed issues with its breathing system, and there were concerns about contamination and whether the air supply was safe.

During one of those repair dives, aquanaut Berry L. Cannon was sent down to assess the situation. His gear relied on a chemical scrubber to remove carbon dioxide from the air he was breathing, a precursor to the so-called rebreathers that are common today. At some point during the dive, the system failed, likely due to a problem with the absorbent material used to filter out CO₂. Without scrubbing, carbon dioxide builds up quickly in a closed breathing loop. The result is confusion, loss of consciousness, and death.

Berry Cannon was gone.

The incident exposed just how narrow the margin for error was. At those depths, even a small equipment issue could become fatal in minutes. It also raised broader concerns about the safety of the entire operation, including whether the systems had been adequately tested under real conditions. People had also died in the space program, but for some reason, this was different.

Within weeks, SEALAB III was shut down.

As Carpenter later put it, the ocean never quite captured the public imagination the way space did. “Work in the deep water is just not as glorious a pursuit in the minds of most people as a flight to the moon,” he told CBS in 1968. “It’s a cold, dirty place, and you can’t see very far. You can’t go down and take pictures that thrill the world.”

It’s hard not to ponder what might have followed if SEALAB had continued. The idea of people living on the ocean floor is still pretty captivating. Not just for science, but also for tourism. Living in the ocean changes how you observe it. It slows things down. It lets the environment reveal itself in ways short visits using scuba never can.

There are several encouraging signs that the idea may not be entirely gone. Projects like DEEP’s Vanguard and Sentinel habitats are revisiting the concept, and could point toward a more permanent human presence on the ocean floor.

This project is new to me. I only discovered it while reporting out this article. DEEP is a British company, but they’ve been building out facilities in both the U.K. and the U.S., including a pilot deployment at Tennessee Reef in the Florida Keys National Marine Sanctuary. This is supposed to happen as early as the end of May 2026. So, wow, yeah. Pretty neat.

This week, I’m taking a slightly different approach to the newsletter—video—though it’s not too far from my usual wheelhouse. I’ve spent over two decades producing visual journalism, from my early days at ABC News in New York, to a long stretch with the New York Times in New York and Berlin, and then with various other outlets (including a recent hour of NOVA for PBS). I’ve always been passionate about visual storytelling. In fact, I’ve said before that to truly tell a story about a place, you need to be there. I still stand by that.

I’ve long held to the idea, perhaps a bit too tightly, that journalists shouldn’t be the story. But in today’s social media landscape, that norm has shifted. So, I’m stepping in front of the camera to tell a few of these stories. I’ll start small, simple standup style, and we’ll see how it evolves. I received some lovely encouragement so far from friends, family, as well as a couple of folks right here on Substack (Thanks, Amanda!). Of course, there will be ample drone footage.

I’ll also be working closely on many stories with my friend and collaborator Tod Mesirow, whose credits include Mythbusters, Sticker Shock, NOVA, and many more. The goal of this Substack remains the same: to help you experience California’s places, people, and hidden stories in richer ways. Video will be an addition, not a replacement, to the longer essays. I hope you enjoy the journey!

Here’s my piece on Mono Lake, one of the most mysterious and beautiful places in California, where chemistry, geology, and biology come together in some really surprising ways.