Deep Sea-ing
In the early 1980s, Francisco Chavez returned to his natal homeland in Peru with his Duke University doctoral adviser, Richard Barber. Like many biologists studying ocean life, Barber had a case of physics envy. Physical oceanographers can precisely measure changes in sea level caused by underwater Kelvin waves that form in the western Pacific, which often herald the arrival of the ocean phenomenon known as El Niño. But Barber and Chavez wanted to measure biological signs of El Niño with commensurate accuracy. At the time, scientists were starting to suspect that El Niño played a major role in driving variation in the global climate, and Barber and Chavez knew species must respond to those changes. “But previous observations indicated that these changes were subtle,” Chavez, now a senior scientist at the Monterey Bay Aquarium Research Institute, told me.
Chavez and Barber started monitoring off the coast of Peru in June 1982. Their methods were simple: every week, they collected samples of water from the side of a small fishing boat, documenting various metrics including plankton density. On September 22 of that year the monitoring site temperature went up five degrees and kept going up. A huge El Niño was underway. “It changed the ecosystem and my PhD thesis at the same time,” Chavez said. The fishery off the coast collapsed. Inland, rainfall brought on by atmospheric changes deeply replenished the desert ecosystem. Gardens bloomed, crops burgeoned, insect populations exploded. “Deer seemed to appear out of nowhere,” Chavez told me. He noticed that the patterns in the ocean drove changes in the social fabric as well. Some livelihoods were decimated while others thrived. For Chavez, understanding the comings and goings of El Niño took on new relevance.
Barber and Chavez published “Biological Consequences of El Niño” in Science in 1983, and Chavez has continued to study these impacts ever since. Over decades, the living patterns of response emerged. Chavez and his collaborators discerned a switch from a warm-water “sardine regime” in the 1970s to a cool-water “anchovy regime” in the 1990s. The biological shift aligned with changes in ocean currents, temperatures, and atmospheric carbon dioxide levels. The correspondence was so clear, Chavez and collaborators wrote in 2003, “it has been suggested that a regime or climate shift may even be best determined by monitoring marine organisms rather than the climate.”
Humanity has long observed natural phenomena, the better to feed itself and to survive. For four centuries, potato farmers in Peru looked to high cirrus clouds for signs of El Niño and its inhibiting influence on rainfall. New Zealand’s Maori people detected incipient El Niños by measuring their annual harvest of shearwater chicks. Sardine and anchovy population changes were noticed well before El Niño and La Niña were associated with the underlying physical causes. These mostly localized observations were generally not considered in the context of global weather and ocean phenomena. Western science is focused on what can be measured and re-measured, which is fair. Until now, our instrumentation has not been adequate to capture the temporal and spatial scales at which species live their lives. It turns out we have been missing vital information.
Today, we are beginning to close the gap. Scientists are using environmental DNA, or eDNA, to help determine where ocean species are, and when, which helps to reveal species interactions with each other and with the physical environment at a fine scale. Focusing on animal behavior, like seabird feeding patterns, helps reveal nuanced ocean weather and current patterns. Citizen-scientist-contributed observations to platforms like iNaturalist and eBird help us see where species are in real time, again revealing their relationships to each other, to the landscape, and to the weather. One exciting development is the so-called “internet of animals.” Biotelemetry devices placed on aquatic species, birds, and mammals enable us to track them at depths of the oceans and heights of the sky otherwise out of our reach. According to Roland Kays and Martin Wikelski, two researchers who have been refining the internet of animals for decades, unparalleled data streams also “describe the world that animals are moving through, including weather, vegetation type, and land use.” Humanity’s mental separation from nature is a perilous roadblock to saving the natural world, but these tools of observation are helping us see how deeply the living and nonliving elements of our world are intertwined. As Wikelski puts it, the goal of all this observation is “to visualize the invisible.”
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Earth’s Collective Intelligence
Humans excel at measuring the nonliving world. We have fantastically advanced our ability to observe through satellite feeds, drones, and globally distributed instruments that show us climate change drivers, often with high accuracy and in real time. The warming of the global ocean over the last half-century shows up in all sorts of ways: fleets of aquatic robots called Argo floats, for example, collect ocean temperature data that tell us that in approximately the last 25 years, the ocean has absorbed heat amounting to five Hiroshima-size atomic bombs of energy per second detonating every second, 24 hours a day.
We are not as good at checking in with the creatures that live in the ocean. That’s a big piece of the puzzle to miss. (Though satellites in space now discern phytoplankton from afar, helping to track their distribution and variability.) Biological species are not just riding along in the ocean; they help create its productivity. As the Peruvian—and California—fisheries make clear, marine life links humanity to the ocean. But it is devilishly hard to keep accurate tabs on where many species are born, where they go for food, and where and how they die.
“There are no coordinated global surveys of biodiversity akin to those for physics,” Chavez told me. “We have a fragmented view of nearshore waters from individual country efforts, but that information is often treated as a matter of national security and therefore is not shared openly and not integrated globally.”
Chavez has increasingly turned his attention to the promise of environmental DNA to quickly and accurately assess the comings and goings of ocean species. Ironically, DNA sampling of the ocean begins with the great simplicity of collecting a sample of water. “You can pick up evidence of life-forms, from bacteria all the way to top predators,” Chavez told me. “You don’t need a net, or a telemetry device.”
A single sample captures the DNA shed by the many organisms that have passed through an environment. Advances in the technology are increasingly making it possible to report on the presence and absence of sea creatures in near real time—a biological mirror to the kind of physical data we get from buoys and satellites. This has enormous implications for fine-tuning fisheries management and for anticipating long term weather patterns. For example, if sardines are detected in the water, it could mean an El Niño is on its way. Returning to Chavez’s original interest from decades ago, it uses the biological to understand the physical.
Birds Decide
“We’ve been monitoring out at the Farallones for 56 years now,” Pete Warzybok, a senior marine ecologist at Point Blue Conservation Science in Petaluma, told me. “Typically, long-term patterns like El Niño and other warm-water events will reduce productivity overall.”
The impacts of a warmer ocean are found to cascade along the food web, from microscopic plankton to blue whales. Point Blue studies El Niño’s impacts particularly on seabirds and marine mammals. “The birds can sense that there may not be enough food to get them into breeding condition in these years,” Warzybok said, “and they’ll start later in the season or even forgo breeding altogether. We’ll see fewer eggs and chicks, and fewer pinniped pups. We’ll see mortality events.”
Warzybok and other researchers expect dips in biodiversity populations as a regular pulse of nature. “We have 30 years of data,” he said, “and we’ve been making models with it.”
Warzybok says that recently these assumptions have been challenged. A pattern once defined by warmer water arriving roughly every seven years with an El Niño now seems to be changing into one where warm events happen every handful of years, and the El Niños are stronger and hotter than they were 25 years ago.
Like Chavez’s work in South America, Point Blue research has seen the biological both following and predicting the physical. Nutrient-rich zooplankton decline when the water warms up. Gelatinous species that contribute less to the food web increase. As El Niño patterns have been changing, Point Blue researchers have documented “habitat compression.” More warm water is pushing the nutrient-rich colder water around, sometimes horizontally, sometimes vertically. You can imagine how some species would be able to dive deep to get at the good stuff, while other species would be out of luck. A Cassin’s auklet could encounter a food desert at the depth it can feed, while a deep-diving murre could still access dinner.
There Goes the Neighborhood
Direct observation also reveals adaptive patterns that occur over longer time periods than we generally examine. El Niño has seemed to me like an ill wind spreading nothing but disaster. In the previous historic El Niño of 2015–16, seabirds starved and desperate marine mammals were seen (by me for one) lumbering along Marina Boulevard in San Francisco. Now the hot waters are coming more often, with more heat, more impact. Cue my primal scream. But the whole picture is more complicated. I learned that El Niño is not always a homewrecker and, in some cases, may actually be lending species a helping hand.
In mid-May this year I headed up to Bodega Bay from San Francisco. Eric Sanford has been monitoring tidepools here for more than 20 years and he darted across the precipitous rocks like a deer. I followed as my knees would have it, ungainly and slow. Sanford is a professor of evolution and ecology at UC Davis and works at the university’s Bodega Marine Lab, a short walk from the water. His partner, Jackie Sones, administers research on the Bodega Marine Reserve and frequently documents invertebrates alongside him. Out on the rocks Sanford perched on the sharp, thin edge of a boulder. I was worried about the lack of tread on his unconstructed rubber boots. Anxiously I kept an eye on the big waves crashing inches from us. A round-faced harbor seal bobbed in the water, its steady gaze reappearing like an aquatic Cheshire cat. It seemed to eye us with intent. Sanford is out there so often, I wondered if the harbor seal recognized him.
Sanford has gotten to know the invertebrates here on something of a personal basis. Consider the owl limpet. “They are territorial,” he told me, pointing out smooth oval shells that seem cemented to various rocks. “Notice the area around the animal.” How many limpets have I blithely passed by without noticing a smooth clearing of rock creating a circumference around them? “That’s the limpet’s garden. At night it will travel across this stretch of rock to eat, and it will bulldoze encroaching mussels or other limpets.”
Garden dining for a limpet means scraping algae off the rock with its radula, something of a cross between a tongue and teeth, which beats out spider’s silk as the strongest known biological structure on earth. Limpets can live for 16 years pretty much in the same spot, to which they return after foraging in their gardens. “You can go out year after year and find the exact same individual on the exact same patch of rock,” Sanford told me. I asked if he had named any of them, but he demurred. “We monitor thousands right here.”
Sanford and I crawled around the rocks, making note not only of limpets but sunburst sea anemones as well, another focus of his research. Again, anemones are long-lived creatures that stay put. South of us a bit at Duxbury Reef in Bolinas, a gigantic anemone you can spy at super low tides is said to be more than 100 years old. “It’s comforting, really,” I mentioned to Sanford, as if the ability of marine invertebrates to stick to a place amid historic change was evidence that humans could do the same. But the sunburst anemones, “these are newcomers here,” Sanford said. Since 2015, Sanford and Sones have monitored more than 37 species from Southern California finding a new neighborhood up north. “Bodega Bay is looking a lot more like Monterey Bay these days,” he told me. El Niño shocks of warm water and north-flowing currents, coming on top of an ocean that’s warmed dramatically due to human-caused climate change, may be the explanation. “As the ocean temperatures warm, species are moving poleward to track warming waters,” Sanford said. “But how can they do that?”
Indeed, the image of a limpet or a sea anemone hopping on an aquatic bus headed north belongs only in a SpongeBob episode. Like all organisms, aquatic species are highly adapted to specific conditions. To survive ocean warming, how would a limpet actually find new ground, so to speak?
“Many marine invertebrates reproduce by way of millions of larvae released into the water,” Sanford explained. “El Niño is a powerful current that acts like an open door allowing them to move across distances they otherwise couldn’t travel.” Part of Sanford’s research is at the intersection of evolution and ecology, and one of his questions here is whether limpets and sea anemones, among other creatures, are evolving by way of natural selection to adapt to their new environment when larvae settle in for the long haul. El Niño brings warmer waters but only temporarily. Not all species that arrive in a more northern habitat will survive when more customary temperatures at Bodega Bay resume. As the ocean changes, more questions will arise. Which species will adapt, which will not? Can we predict responses, can we help species that need a leg up?
The Internet of Animals
Monitoring tidepools, Sanford, Sones and many others are watching complex interactions between species and climate unfold. Human impacts are rearranging ecosystems, bringing new communities of species together, tearing others apart. The good news is, we are getting better at using technology to monitor nature as never before. The “internet of animals” is already in operation and set to become more robust in coming years. Martin Wikelski and colleagues have labored for decades in support of a global system of sensors by which we can track species to deeper depths, higher heights, and into wavelengths not discernible by the human ear. In 2018 the space-based system ICARUS (International Cooperation for Animal Research Using Space) sent a receiver connected to thousands of animal sensors into space with a Russian rocket; technical and geopolitical difficulties curtailed the effort. Wikelski’s team pivoted and is set to launch ICARUS receivers on CubeSats, miniature satellites funded not by industry but by the Max Planck Society, which will help protect the project from geopolitical vagaries. Thousands of animals wearing tags linked to these receivers will report out on abiotic, or nonliving, environmental factors like air pressure and temperature and biotic signals like the animal’s caloric output; researchers will even attempt to interpret what’s going on by using AI.
In addition to providing revolutionary data about how the earth system works, Wikelski sees a wealth of generalizable data in the behavior of birds and other creatures. Studying migrating birds affixed with telemetry devices, Wikelski and colleagues were stunned to discover different bird species communicating with each other in the night sky, constantly chirping, “discussing which altitude to fly at and which direction to take.” This revelation helped upend the assumption that birds migrate based on genetic information alone. “By communicating with others, each individual bird taps into a communal knowledge bank built up by billions of animals over vast stretches of time,” Wikelski said. Listening in, we can learn from them too.
Seeing, Feeling, Taking Note
In addition to all the instrumentation ever-refining our ability to see, there is the invaluable contribution of citizen science. On June 1, I joined Fort Ross Conservancy ecologist Dione Deaker and a handful of tidepool enthusiasts at Fort Ross, on the coast about 25 miles north of Bodega Bay. We were there to count marine invertebrates as part of Snapshot Cal Coast, a community science project of the California Academy of Sciences, which is building a model of reality based on human-driven observations. Snapshot Cal Coast enlists thousands of people to go out and intensively monitor the edge between ocean and land in Northern California, and this year the window of time was extended to a month. Snapshot Cal Coast data has been instrumental to tracking the kind of species distribution changes monitored by Eric Sanford and Jackie Sones. My very first day out in the tidepool with the Academy in 2012, we photographed the Pepto-Bismol-pink nudibranch called Hopkin’s rose, a southern species that more than 10 years ago began testing northern waters—its niche has historically been Southern California.
Among our group at Fort Ross, some had read about Snapshot Cal Coast on a flyer and others were die-hard nature lovers well acquainted with California’s glorious embrace of the Pacific. Physical modelers have a globally distributed network of satellites and buoys, but part of the reality of biological observation in the 21st century is that we have a globally distributed network of people carrying smartphones. The 2024 snapshot at Fort Ross tallied up to 263 observations of 127 species.
The winds focused our tidepooling a bit. The disturbed surface waters occlude visibility and make it harder to see what’s below. We documented congregating anemones, snails, and scuttling crabs, and for a while we all fixated on tiny sculpin darting among the rocks. Snapshot Cal Coast data is automatically counted up by way of iNaturalist, aided and abetted by GPS location, the date, and the time of photographic observations. When Deaker joined Fort Ross, she was bequeathed a large cardboard box of sea lion survey forms with the explanation: “Here’s our data.” Today she collates the work of volunteers and gives their harbor seal data to the nearby Point Reyes National Seashore, which coordinates a larger marine mammal observation network.
After several hours we were not quite ready to leave the suspension of the glorious rocks and insistent breeze. We unfurled ourselves from the tidepool and stood up to take in the broader expanse, filled with foaming breakers. “That’s upwelling in action,” Deaker remarked, referring to the result of winds and currents that help drive the food web. In all my many years of staring at waves, I had never quite thought about why they were moving in a particular direction, and what that meant to the creatures below. A harbor seal popped its head up and seemed to look me in the eye. What was it trying to tell me? My joy was that given all that humanity has been throwing at its species and its habitat, it was still there.
SIDEBAR
A Model World
For reasons not fully understood, 2023 was the hottest year in recorded history. The ocean broke temperature records every day for almost nine months. September 2023 was the hottest month ever recorded. So far 2024 is continuing the upward trend. Scientists have called today’s ocean temperatures “unprecedented,” “alarming,” and “crazy.” Marine heat waves are occurring across the Northern Hemisphere, and nobody knows what it means for life on earth. It’s possible that these “unprecedented” temperatures are a normal anomaly and will recede in time. It’s also possible that temperatures will just keep rising from here. El Niño and La Niña have historically helped predict weather, but the background ocean conditions of these events have now superseded their influence. National Oceanic and Atmospheric Administration researcher Michelle L’Heureux commented that now, “El Niño and La Niña are just changing the details.” Jennifer Francis of the Woodwell Climate Research Center notes that El Niño and its cool-water counterpart La Niña have been important for figuring out what the weather is going to do months in advance, but “now there’s a lot more going on.”
Partly because we can do such a good job of it, researchers track climate change mostly through abiotic, or nonliving, signals like temperature and precipitation. El Niño and other ocean-atmosphere events are also tracked by wind and currents, which of course are also nonliving phenomena. But right now, the abiotic approach may be hitting a proverbial brick wall. It relies on the historical record to put current markers in context. Today’s temperatures are so much higher than ever before (and continuing to rise) that scientists sometimes say we are in a “no analogue” world. We don’t quite know what to make of our numbers right now. It’s likely that species living far closer to nature’s pulse than we do can shed some light on the subject.
The impact of an ocean phenomenon on global temperatures is a reminder that, in the words of John Largier, director of the Bodega Marine Lab at UC Davis, where Eric Sanford and Jackie Sones work, “it is a blue planet.” The world’s oceans represent more than 70 percent of the surface area of the earth, and water has a much higher capacity to absorb carbon dioxide than land does. Largier oversees many varieties of marine observation distributed around 30 locations, measuring phytoplankton, temperature, and salinity and sampling for harmful algae blooms. The Bodega lab data connects with networks of these observations all up and down the coast. “One importance of continuous observations,” he told me, “is that without them we would have no idea what is wrong with our models. Models are a reduction of reality and to some extent we make them so we can see how they deviate from reality.” Looked at this way, the 2023 El Niño is not a mistake in our climate models, but an opportunity to help fine-tune them. “When models are wrong it’s not a failure,” Largier said. “It’s a stepping stone.” Largier pointed out that as terrestrial creatures, we have little intuition about how the ocean works. “We’re not marine animals, and we don’t have a great sense of the patterns,” he said. “Observing the ocean helps develop our intuition a bit.”
Support for this article was provided by the March Conservation Fund.
