echinoderms
Beyond biodiversity: A new way of looking at how species interconnect.
In a development that has important implications for conservation, scientists are increasingly focusing not just on what species are present in an ecosystem, but on the roles that certain key species play in shaping their environment.
In 1966, an ecologist at the University of Washington named Robert Paine removed all the ochre starfish from a short stretch of Pacific shoreline on Washington’s Olympic Peninsula. The absence of the predator had a dramatic effect on its ecosystem. In less than a year, a diverse tidal environment collapsed into a monoculture of mussels because the starfish was no longer around to eat them.
By keeping mussel numbers down, the starfish had allowed many other species to thrive, from seaweed to sponges. Paine’s research led to the well-known concept of keystone species: The idea that some species in an ecosystem have prevailing traits — in this case preying on mussels — whose importance is far greater than the dominant traits of other species in that ecosystem.
Now, a half-century later, researchers are taking the study of traits much farther, with some scientists concluding that understanding the function of species can tell us more about ecosystems than knowing which species are present — a concept known as functional diversity. This idea is not merely academic, as scientists say that understanding functional diversity can play an important role in shaping conservation programs to enhance biodiversity and preserve or restore ecosystems.
“The trait perspective is very powerful,” says Jonathan Lefcheck, a researcher at the Bigelow Marine Lab in East Boothbay, Maine who studies functional diversity in marine environments. “Some species in an ecosystem are redundant, and some species are very powerful.”
Much about the concept is also unknown. One case study is taking place along the Mekong River, a 2,700-mile waterway that serves as a vital fishery for millions of people in Southeast Asia. While the fishery is healthy now, widespread changes in the ecosystem — including the proposed construction of numerous dams and the development of riparian forests and wetlands — could mean that key fish species might not be around to carry out important functions, such as keeping prey numbers in check or recycling nutrients.
“There is simply no understanding of how the construction of a dam today, and another five years from now, and another in 10 years — all in the same river basin — will impact the biodiversity and push it past a point of no return, where large scale species extinctions are imminent,” said Leo Saenz, director of eco-hydrology for Conservation International.
So a team of ecologists from Conservation International is trying to determine which roles various species in the Mekong fill that are critical to perpetuating a healthy ecosystem. Those species might be predators like the giant snakehead, which helps control other fish populations so they don’t become too numerous, or thick groves of mangrove forests in shallow areas that provide a nursery for a wide variety of fish species. Models can then predict the best way to protect these key species and ensure a healthy river over the long term.
“Ecosystem resilience is an important part of what we aim to maintain, both for the interest of biodiversity conservation and for the maintenance of the ecosystem services that nature provides,” says Trond Larsen, a biologist who heads Conservation International’s Rapid Assessment Program for biodiversity.
Some scientists now compare knowing which species are present in an ecosystem to knowing only which parts of a car are present. Functional trait ecology is a deeper dive into ecosystem dynamics to help understand how the parts come together to create a natural environment that runs smoothly, like a well-tuned automobile, thus enabling a more focused protection of the vital parts that keep it going.
“Say you have two habitats with 10 different species in each,” explains Marc Cadotte, a professor of Urban Forest Conservation and Biology at the University of Toronto. “Yet, they might not be comparable at all if in one of those habitats eight of those 10 species are similar and redundant, while in the other habitat, all 10 species are unique from one other. We need alternative measures for biodiversity that tell us something about the niche differences, trait differences, how species are interacting, and how they are using resources. Functional diversity and phylogenetic diversity are meant to capture that.”
Phylogenetic diversity refers to species that have few or no close relatives and that are very different from other species, which may mean that they can contribute in very different ways to an ecosystem. Protecting phylogenetic diversity, then, is part of protecting important functions. The distinctive pearl bubble coral is one example, as it provides shelter to shrimp, an important food for the highly endangered hawksbill turtle.
Better understanding these aspects of ecosystems is a game-changer for the conservation of biodiversity. The Indo-West Pacific region, between the east coast of Africa and South Asia, has the highest diversity of life in the world’s oceans. But many species there, such as damselfishes and butterfly fishes, have a lot of overlap with other species in terms of traits — somewhat similar body sizes, similar habitats and habits, how and where they school, etc. That means they may have a narrower range of traits that may be important for ecosystem function.
“In the Galapagos, on the other hand, there are fewer species, but each of those species is doing something much different than the others,” says Lefcheck, who worked on research looking at functional diversity there. “If you were prioritizing your conservation efforts, you might focus on the Galapagos. Even though it doesn’t have as much biodiversity in the traditional sense, it has a much greater diversity of form and function.”
“Functional diversity is incredibly difficult to determine,” says Larsen of Conservation International, “but generating an improved understanding of the relationship between species and their functional diversity is key to understanding and mitigating impacts or threats from development.” His organization works to protect tuna and sharks, for example, because these predators help maintain a healthy and balanced ecosystem by keeping numbers of prey from growing too large and by culling the sick and the weak.
In a recent study in the journal Nature, researchers say that focusing on species function and evolutionary heritage can narrow the focus on what needs to be protected most urgently. “Biodiversity conservation has mostly focused on species, but some species may offer much more critical or unique functions or evolutionary heritage than others — something current conservation planning does not readily address,” says Walter Jetz, a professor of ecology and evolutionary biology at Yale University.
The researchers noted that 26 percent of the world’s bird and mammal species are not included in protected reserves. Focusing on the most important traits and evolutionary heritage of those species would allow conservationists to narrow their protection of critical biodiversity with just a 5 percent increase in protected areas, and would be far less costly than trying to protect them all, the Nature study shows.
As traits are better understood in ecosystems, Lefcheck says, it allows tweaking and management of ecosystems for certain outcomes. “You could choose to conserve the species that are very different than others that might lead to changes in the ecosystem that could be considered beneficial,” he says. That has potential for fisheries management, for example. “When I tell someone, ‘This species has been around for 2.6 million years,’ that’s very esoteric in a way,” says Lefcheck. “But if I can say, ‘This large-bodied species produces a lot of biomass, and it can crop down invasive algae, and it plays a high-functioning and critical role in the ecosystem,’ you might want to protect species that have that trait.”
Such is the case with parrotfish and surgeonfish — “reef-grazers” that eat algae and keep coral reefs healthy. Because of these key traits, the government of Belize has enacted a law to protect these two species.
Understanding traits also can enhance ecosystem restoration projects. While building a new oyster aquaculture fishery can provide a commercial harvest, “we also know that oysters provide a lot of other services,” says Lefcheck. “They filter the water. They provide nooks and crannies for small fish and invertebrates to live in, and they are fish food for the tasty things we like to catch and to put on the dinner table. Where is the optimum placement of this restoration to enhance the variety of services we get from the oysters beyond just having the reefs there?”
The benefits of understanding functional diversity can go well beyond ecosystem restoration. In Toronto, for example, green (plant-covered) roofs are required on most new commercial buildings to help cool the city and reduce storm water runoff. A monoculture of grass called sedum is used. In studies, though, Cadotte and colleagues have found that if grass species that are distantly related and dissimilar are used in the mix, they have different traits that provide more shade for the soil and help the roof keep the building cooler. This mix also reduces stormwater runoff by about 20 percent.
The formal study of functional traits can be traced back to the 1990s, when ecologist David Tilman at the University of Minnesota did research on grasslands. He found that those regions with more species diversity did better during a drought, and only a few of the grasses resistant to drought were needed. Later, he and his colleagues discovered that the presence of some grasses with certain traits, such as an ability to fix nitrogen, was more important than overall species diversity.
Researchers in Jena, Germany established the Jena Experiment to follow up on this work. They found that there are plants, such as wild tobacco, that emit “messenger molecules” when they are under assault by herbivores to attract predators from miles away that eat their enemies. This trait not only benefits the tobacco, but other species in the neighboring plant community.
Experts say these findings could also help agriculture rely less on pesticides by understanding the right mix of plants to maximize predator defenses. “Varying the expression of just a few genes in a few individuals can have large protective effects for the whole field,” says Meredith Schuman, a researcher on the Jena Experiment at the Max Planck Institute for Chemical Ecology. “It’s an economically tenable way to recover the lost benefits of biodiversity for the vast expanses of land that have already been converted from natural, biodiverse habitats into agricultural monocultures.”
These new approaches to ecology show how limited the science has been. Many researchers welcome the change. “Ecology has moved from counting species to accounting for species,” says Cadotte.
Jim Robbins is a veteran journalist based in Helena, Montana. He has written for the New York Times, Conde Nast Traveler, and numerous other publications. His latest book, The Wonder of Birds: What they Tell Us about the World, Ourselves and a Better Future, is due out in May.
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Rob
High marine extinction risk by 2100.
If marine extinction is not a reality for many species by the end of this century, scientists say, it will certainly be a strong probability.
Mass marine extinction may be inevitable. If humans go on burning fossil fuels under the notorious “business as usual” scenario, then by 2100 they will have added so much carbon to the world’s oceans that a sixth mass extinction of marine species will follow, inexorably.
And even if the 197 nations that agreed in Paris in 2015 to take steps to limit global warming in fact do so, then by 2100 humans will have added 300 billion tons of carbon to the seas. And a US scientist has calculated that the critical threshold for mass extinction stands at 310 billion tons.
So in either case, the world will be condemned to, or at imminent risk of, a “great dying” of the kind that characterised the end of the geological period called the Permian, in which 95% of marine species vanished, or the Cretaceous era that witnessed the last of the dinosaurs.
Daniel Rothman, a geophysicist at the Massachusetts Institute of Technology, reports in the journal Science Advances that he worked through hundreds of scientific studies to identify 31 occasions of significant change in 542 million years in the planet’s carbon cycle – in which plants draw down carbon from the atmosphere and cycle it through the animal community and back into the atmosphere.
Happening now
For each event, including the five great mass extinctions in the geological record, he estimated the record of carbon preserved in the rocks, to find a predictable threshold at which catastrophe might be an outcome. Four of the five great extinction events lay beyond this threshold. He then considered the timescales of such extinction events to arrive at his modern-day danger zone figure of 310 billion tons.
And by 2100, unconstrained fossil fuel combustion may have tipped the planet into “unknown territory,” he says.
“This is not saying that disaster occurs the next day. It’s saying that, if left unchecked, the carbon cycle would move into a realm which would no longer be stable, and would behave in a way that would be difficult to predict. In the geologic past, this type of behaviour is associated with mass extinction.”
In effect, Professor Rothman has used a mathematical technique to predict an event many biologists believe is already happening. Pollution, the clearing of the wilderness and the disruption of habitat have already placed many species at risk. Global warming as a consequence of the combustion of fossil fuels will, they have repeatedly said, make a bad situation worse.
“Our activities as humans are pushing species to the brink so fast that it’s impossible for conservationists to assess the declines in real time. Even those species that we thought were abundant and safe now face an imminent threat of extinction”
Researchers have already begun to record local extinctions – the disappearance of once-familiar creatures from local landscapes – and climate change that will follow global warming could heighten the hazard for animals and plants already under stress.
And Professor Rothman’s warning came hard on the heels of several studies that indicate the dangerous impact of climate change.
Scientists from the University of Washington in Seattle warn that as the world’s waters warm, fish will have to migrate to survive, and those that cannot – the ones in lakes and river systems – could be at risk.
They report in the journal Nature Climate Change that they looked at available physiological data and climate predictions to see how 3,000 species in oceans and rivers would respond to warmer waters and to judge what the “breaking point” temperatures for any species would be.
Many losers
“Nowhere on Earth are fish spared from having to cope with climate change”, said senior author Julian Olden, professor of aquatic and fishery sciences. “Fish have unique challenges – they either have to make rapid movements to track their temperature requirements, or they will be forced to adapt quickly.”
But other creatures in the most extreme environments are affected too. British Antarctic Survey scientists report in Nature Climate Change that they used computer models to test a warming scenario for 900 species of marine invertebrates that live in the south polar seas.
Even a small warming of 0.4°C will cause unique local animals to change their distribution, and although some will fare well, overall there will be more losers than winners.
“While a few species might thrive at least during the early decades of warming, the future for a whole range of invertebrates from starfish to corals is bleak, and there’s nowhere to swim to, nowhere to hide when you’re sitting on the bottom of the world’s coldest and most southerly ocean and it’s getting warmer by the decade”, said Huw Griffiths, the Survey scientist who led the research.
Africa in jeopardy
As if to hammer home the message, the International Union for the Conservation of Nature has just issued its latest warnings on imminent extinction. This international body has now rated 25,062 species as in danger of extinction out of a list of more than 87,000.
The latest list includes five of the six species of ash tree native to North America, some of them threatened by an invasive beetle infestation, helped by global warming, and five species of African antelope.
“Our activities as humans are pushing species to the brink so fast that it’s impossible for conservationists to assess the declines in real time,” says Inger Andersen, director general of the IUCN.
“Even those species that we thought were abundant and safe – such as antelopes in Africa or ash trees in the US – now face an imminent threat of extinction.”
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Chesapeake acidification could compound issues already facing the bay, researchers find.
As oceans around the world absorb carbon dioxide and acidify, the changes are likely to come faster to the nation’s largest estuary.
For ten days across recent summers, researchers aboard the University of Delaware research vessel Hugh R. Sharp collected water samples from the mouth of the Susquehanna River to Solomons Island in a first-of-its-kind investigation. They wanted to know when and where the waters of the Chesapeake Bay were turning most acidic.
One finding: As oceans around the world absorb carbon dioxide and acidify, the changes are likely to come faster to the nation’s largest estuary.
Scientists have long studied the slow and steady acidification of the open oceans — and its negative effects. Acidifying waters can kill coral, disrupt oyster reproduction, dissolve snail shells like nails in a can of bubbly Coke.
But researchers are just beginning to investigate the consequences for the Chesapeake. And they’re finding that acidification could compound the ecological challenges already wracking the bay.
Not all effects are immediately negative on all species. Experiments are showing that blue crabs, marsh grasses and algae could theoretically thrive in the conditions expected to develop over the next century. But the acidification is a threat to other keystone bay species, such as oysters — a key source of food for crabs. Scientists say acidification could dramatically and unpredictably alter the delicate balances that stabilize the bay ecosystem.
With so many variables expected to affect bay creatures — including rising acidity, warming waters and continued nutrient pollution — research is complex.
“When you have three things changing at once, that’s where our challenges really increase,” said Jeff Cornwell, a research professor at the University of Maryland Center for Environmental Science in Cambridge. “All these things are intertwined.”
Water, as they teach in middle school chemistry, has a neutral pH of 7. But over the past 300 million years or so, ocean water has registered as basic, with an average pH of 8.2.
As carbon dioxide has multiplied in the atmosphere over the past century, it has also dissolved into the oceans, producing carbonic acid. That has dropped ocean pH to 8.1. The shift might seem slight, but it actually represents a 30 percent increase in acidity, because the pH scale is logarithmic.
The consequences, coupled with the impacts of rising ocean temperatures, could eventually be severe. Research suggests that the acidity that could develop by 2100 could make it harder for oysters, clams, sea urchins and corals to build their protective shells, and could even dissolve the shell of the pea-sized creature at the base of the food web known as a sea butterfly.
But that’s just in the open ocean. Most research focuses on that massive habitat, because its chemistry is largely consistent from one spot to another. In environments close to land, where ecology is more complex and active, biological processes like photosynthesis and respiration drive more volatile swings in acidity and other chemistry.
Whitman Miller is a research scientist at the Smithsonian Environmental Research Center in Edgewater.
If an acidifying ocean is like a bottle of carbonated seltzer water, he said, estuaries like the Chesapeake are similar to a beer.
“Because it’s so uniform, in some ways, we know much more about the open ocean at the global scale than we do these local scales we’re tangling with in estuaries,” he said.
Researchers around Maryland and across the country are working to bridge that knowledge gap.
Research published last month in the journal Nature Communications showed that acidification is already apparent in the bay. The team that measured acidity across the bay, led by the University of Delaware marine science professor Wei-Jun Cai, found a zone of increasing acidity at depths of about 30 to 50 feet across the Chesapeake. While surface waters hover around the pH norm of 8.2, the deeper waters registered almost one point lower — nearly ten times more acidic.
The researchers, who included Cornwell and colleagues from UMCES, believe it’s not only the global effects of carbon dioxide emissions, but also the dead zones of low or no oxygen that have plagued the bay for decades. The zones are created when nitrogen and phosphorus runoff from farms, lawns and sewage fertilize large algae blooms. Microbes strip oxygen from the water to decompose the blooms when they die, and release more carbon dioxide in the process.
The problem is worsened when organic matter is decomposed in water that is already stripped of oxygen — the bacteria use up other compounds in the water that produce an acidic chemical, hydrogen sulfide. Hydrogen sulfide is what makes the muck around the bay smell like rotten eggs.
Cai said the processes suggest that the bay, and other waterways struggling to reduce nutrient loads, are especially vulnerable as the pH of waters around the globe decline.
“You have something we call a synergistic effect, where one plus one gives you something more than two,” he said. “There’s a very strong acidification effect.”
Miller and colleagues at the Smithsonian are exploring the consequences in a meadow of marsh in that looks like so many others around the Chesapeake — except this one is dotted with metal heat lamps and plexiglass chambers that are helping to simulate the environment of the future. They call it the Global Change Research Wetland.
Scientists are conducting experiments to study the effects of increasing carbon dioxide, nutrients and temperature on the growth of sedge grasses and invasive plants, and the ability of the Rhode River marsh to grow upward to match sea level rise.
One study has been running for 30 years. Pat Megonigal, a biogeochemist and lead investigator of the research wetland, says it should be listed in the Guinness Book of World Records for the longest-running climate change experiment.
Along the creek that flows into the marsh, researchers from the Smithsonian Institute have built a gateway through which they are measuring the carbon content of water as it flows in and out twice a day with the tides. Some of it is carbon dioxide, but a portion is the compounds carbonate and bicarbonate — elements that may actually help counteract acidification in the estuary.
They hope the data will help explain not only what changes acidification could bring, but also what role natural ecological processes could play in limiting them.
“It tells us something about the influence of the marsh on the chemistry of the water,” Megonigal said. “We think the net effect of water leaving the marsh is to buffer the acidity of the estuary.”
Other researchers are eagerly testing what those changes could mean for the bay’s crabs and oysters.
For her recently completed dissertation, UMCES doctoral candidate Hillary Glandon exposed blue crabs to both warmer and more acidic waters and watched their response. She found that acidification alone didn’t affect them, but when it was coupled with warmer waters, crabs grew faster, molting old shells more frequently, and they also ate more food.
Previous research has already shown that oysters, mussels and similar shellfish could struggle in acidifying waters. They build their shells out of a compound in the water known as calcium carbonate, and scientists have found there will be less of those building blocks available as ocean carbon dioxide levels rise.
So Glandon’s colleagues Cornwell and Jeremy Testa are investigating what that could mean for restoration of the Chesapeake Bay’s oysters. They’re getting input from researchers in Oregon, where acidification has already challenged aquaculture efforts by killing oyster larvae. Though they don’t expect the exact same conditions in the bay, they are watching pH levels closely in places such as Harris Creek, one of three Choptank River tributaries where millions of dollars have been spent on building and seeding new reefs.
Any changes could throw off a complex food web. While crabs could be thriving in warmer and more acidic bay waters in the future, the oysters and mussels they eat could be struggling.
“Crabs don’t exist in a vacuum,” Glandon said. “If food they’re going to be eating is less abundant, there may be negative effects.”
Tom Miller, director of UMCES’ Chesapeake Biological Laboratory in Solomons, said the stakes demand that more resources be put into measuring and understanding acidification. In the same way state and federal officials have tried to limit pollution to protect crabs, oysters, marshes and underwater grasses, he said, acidification should be getting more attention in bay policy discussions.
“It has the potential to fundamentally change the pattern, the seasonality and the location of fishing in a way that the grandfathers of today’s watermen wouldn’t recognize,” he said. “We should be having those discussions now — not in 20 years or so, when it becomes, I wouldn’t say too late, but when it becomes much more contentious.”
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NOAA
What scientists are learning about the impact of an acidifying ocean.
The effects of ocean acidification on marine life have only become widely recognized in the past decade. Now researchers are rapidly expanding the scope of investigations into what falling pH means for ocean ecosystems.
THE OCEAN IS becoming increasingly acidic as climate change accelerates and scientists are ramping up investigations into the impact on marine life and ecosystems. In just a few years, the young field of ocean acidification research has expanded rapidly – progressing from short-term experiments on single species to complex, long-term studies that encompass interactions across interdependent species.
“Like any discipline, it takes it time to mature, and now we’re seeing that maturing process,” said Shallin Busch, who studies ocean acidification at the National Oceanic and Atmospheric Administration’s (NOAA) Northwest Fisheries Science Center in Seattle.
As the ocean absorbs carbon dioxide from the burning of fossil fuels, the pH of seawater falls. The resulting increase in acidity hinders the ability of coral, crabs, oysters, clams and other marine animals to form shells and skeletons made of calcium carbonate. While the greenhouse gas effect from pumping carbon dioxide into the atmosphere has been known for decades, it wasn’t until the mid-2000s that the impacts of ocean acidification became widely recognized. In fact, there is no mention of acidification in the first three reports from the United Nations Intergovernmental Panel on Climate Change, issued in 1990, 1995 and 2001. Ocean acidification did receive a brief mention in the 2007 report summarizing the then-current state of climate science, and finally was discussed at length in the latest edition released in 2014.
But about halfway through that brief dozen years of acidification research, a shift started taking place.
“The early studies were just a first step and often quite simple,” said Busch of ocean acidification research. “But you can’t jump into the deep end before you learn how to swim.”
That started to change about five or six years ago, according to Philip Munday, who researches acidification effects on coral reefs at Australia’s James Cook University. “The first studies were often single species tested against ocean acidification conditions, often quite extreme conditions over short periods of time,” he said. “Now people are working on co-occurring stresses in longer-term experiments.”
That includes studying how acidification could change how organisms across a community or ecosystem interact – in other words, how the impacts on one species affect those it eats, competes with or that eat it. It also means looking at how impacts could change over time, due to species migrating or adapting, either in the short term or across a number of generations and how such effects may vary within the same species or even with the same population.
Nine examples of this new generation of acidification research are included in the latest issue of the journal Biology Letters. One study, for example, found that the ability to adapt to pH changes differed in members of the same species of sea urchins based on location. Another discovered that a predatory cone snail was more active in waters with elevated carbon dioxide levels but was less successful at capturing prey, reducing predation on a conch species. Another highlights that an individual organism’s sex can affect its response to acidification.
Munday, who edited the series of papers, said one of the major takeaways is that researchers are increasingly studying the potential for species to adapt to ocean acidification and finding those adaptations can be quite complex.
He pointed to a study on oysters. Previous work had shown that oysters whose parents were exposed to acidification conditions do better in those conditions than those whose parents weren’t. But in a new study, researchers found that when they exposed the offspring to additional stressors – such as hotter water temperatures and higher salinity – those adaptive advantages decreased.
All the studies call for including often-overlooked factors such as sex, location or changes in predation rate in future studies. Otherwise, researchers warn, impacts will be increasingly difficult to predict as the ocean continues to acidify.
“It’s far too early to make any sort of generalities,” Munday said.
The latest paper from NOAA’s Busch also cautions against generalities. By building a database of species in Puget Sound and their sensitivity to changes in dissolved calcium carbonate, she found that summarizing species’ sensitivity by class or order rather than the specific family can result in overestimating their sensitivity.
She compared it to similarities between people in the same immediate family versus people who are distant cousins. “There would be a lot more variation among those people because they’re not super closely related,” she said. “But when people started summarizing data really early in the field, there wasn’t much data to pull from. So it was done at a class level.
“Now that we have many more studies and information to pull from, how we draw summaries of species response should be nuanced,” she added.
Acidification research is likely to get only more nuanced in the years ahead. From the broad initial projections of average, ocean-wide surface acidity, for instance, researchers have started to pinpoint local pH projections, local impacts and local adaptations.
“We know the ocean is changing in a number of ways,” said Busch. “So just studying one of those factors without looking at the other changes in what’s going on in the ocean is not going to yield useful results.”
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Fighting for a foothold.
White abalone are both critically endangered and crucial to their coastal ecosystems, so scientists have launched a Hail Mary effort to save them.
SOLUTIONS | 09.19.17
Fighting for a Foothold
White abalone are both critically endangered and crucial to their coastal ecosystems, so scientists have launched a Hail Mary effort to save them.
Story by Gloria Dickie
Photographs by Kathryn Whitney
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Kristin Aquilino pushes open a heavy metal door with a small sign bearing the words, White Abalone Spawning and Culturing in Process. “This is where the magic happens,” says Aquilino, who directs the white abalone captive breeding program here at the UC Davis Bodega Marine Laboratory, an expansive research facility situated on a windy, jagged stretch of coastline in northern California. It’s shortly after 7 a.m., and she and her team have already been at work for several hours.
Today is Spawning Day—the one time each year when white abalone can be coaxed to release their sperm and eggs, giving researchers the chance to rear the next generation. Each of the 14 brood stock in their care, including the only wild-born white abalone female in captivity, sits in its own bucket, bathing in a hydrogen peroxide solution that, after a few hours, should stimulate the mollusk to spawn. “There’s a lot on the line,” Aquilino explains. With white abalone (Haliotis sorenseni) failing to reproduce in the wild, this program is essential to the species’ survival. But she doesn’t have high hopes for the new wild female, which released eggs out of stress when divers collected her in Southern California a few weeks earlier. “My guess is she’s done.”
White abalone once numbered in the millions, from Point Conception, near Santa Barbara, California to Punta Abreojos, Mexico, more than 1,200 kilometers (800 miles) to the south. Today, only about 2,000 isolated survivors remain along California’s coast, where the species is considered to be functionally extinct. No two individuals live near enough—within 2 meters (6 feet) of one another—for their sperm and eggs to meet when released into the water. As white abalone numbers have fallen, other creatures have proliferated in their wake. Urchins now overgraze the fragile kelp forests that protect coastlines from eroding into the sea. Despite conservation efforts, abalone numbers have continued to drop in recent decades. Researchers have been left with no choice but to try to breed the animals in captivity and release them into the wilds of the California Coast in a last-ditch effort to save the species—and the habitat they shore up.
Just after 9:00 a.m., an hour earlier than anticipated, there’s a sudden flurry of activity as technicians cluster around one of the white buckets. Wild abalone 312 is spawning. “You go girl!” yips Aquilino, as a cloud of brown eggs shoots out of one of the respiratory pores on her shell—an orifice through which the animals both breathe and release eggs or sperm. Given the unlikelihood that this abalone lived near a male in the wild, Aquilino says this could be the first time she’s had a chance to reproduce in decades. “That’s a very long dry spell,” Aquilino says, especially for an animal with a lifespan of 35 to 40 years. Ten minutes later, in 309’s bucket, a cloud of milky abalone ejaculate plumes, and technicians swiftly elbow their way in with pipettes to collect the sperm. In a matter of minutes, Aquilino is inside a refrigerated fertilization room and singularly focused, mixing the fresh sperm and eggs in precise ratios. “It’s like Match.com with 309 and 312,” she says, injecting a dropper-full of sperm into a pitcher of eggs.
After more than a decade of trial-and-error, white abalone are finally hitting their stride in captivity. By day’s end, the wild female will have spawned some 700,000 viable eggs—introducing new genes into the captive population for the first time in 14 years. In total, the team estimated they had created 8 million embryos—20,000 of which they expect to make it to the adult stage. That’s in addition to the tens of thousands of juveniles researchers have already reared in their nursery.
As scientists prepare to release the first captive-bred individuals into the wild in the next year or so, much remains unknown about the ecological role of the marine invertebrate and the rising threats to their long-term recovery: a mysterious disease brought on by warm waters, the predators that exploit naive captive-raised abalone, and the yet-to-be-determined impacts of climate change. Indeed, the coast is hardly clear for abalone in California.
In the wild, white abalone typically live a hundred feet or more below the surface, so researchers often use remotely-operated submersible vehicles to study them. As a result, research on the basics of abalone biology and ecology has been slow, and scientists were largely unaware of the rapid decline of abalone populations until it was almost too late.
“Abalone’s ultimate downfall is that they’re delicious,” says Jenny Hofmeister, a marine scientist at the Scripps Institution of Oceanography. White abalone, highly prized by markets in Asia and restaurants in stateside Chinatowns, are said to be tastier than the red, black, pink, or green abalone species. In the 1970s, California opened up a commercial fishery for white abalone, and divers gathered the animals by the hundreds of thousands. As white abalone became rarer in the wild, the price per pound jumped from $2.50 in 1981 to $7 in 1993—roughly double the value of other abalone species. Before long, the abalone that remained on the seafloor were too few and far between to reproduce.
Fearing extinction, the California Department of Fish and Game banned commercial fishing of white abalone in 1996 and of all abalone species in 1997. Today, the only fishery that remains is for recreational fishing of red abalone in northern California, where their densities are still sustainable. But that hasn’t stopped white abalone from showing up in fishermen’s hauls. Today, a single white abalone can sell for hundreds of dollars—a temptation some divers are unable to resist. Aquilino says she’s heard people describe it as “finding a $100 bill on the ocean floor.”
Based on surveys conducted in the 1990s showing that white abalone populations had declined by 99 percent in southern California in just two decades, the species was designated as a candidate for listing under the Endangered Species Act. Petitions from the Center for Biological Diversity and the Marine Conservation Biology Institute eventually led to the white abalone being listed in 2001—the first marine invertebrate to receive federal protection. In the years that followed, scientists and the government mounted a valiant effort to bring the animal back from the brink, but white abalone numbers continued to drop. Between 2002 and 2011, some of the sparse, wild California populations declined by an additional 78 percent.
“Something knocked them out,” says Buzz Owen, 82, a retired commercial fisherman and avid abalone researcher who first described hybridization among various species. “But there were multiple things at work.”
On top of illegal harvests, a disease called Withering Foot Syndrome first showed up near the Channel Islands off the southern California Coast in 1986, and by the 1990s it had spread to waters near the mainland. Once infected, abalone stop eating. The abalone is then forced to consume its own body mass, causing the foot muscle to wither and lose its life-giving grip on the rocky seafloor. The deadly disease affects every abalone species in California, but white abalone are particularly hard hit.
Even more troubling, the emergence of Withering Foot Syndrome is temperature-dependent. A white abalone in a lab, under optimal conditions, can be infected with the pathogen and not experience any symptoms. But as soon as the water temperature warms to between 18 and 20 degrees Celsius (64 and 68 degrees Fahrenheit), the disease kicks in, killing the mollusk within months.
In the wild, white abalone occupy deep waters that are normally cool enough to keep them healthy. But between 2014 and 2016, El Niño and an anomalous mass of warm water meteorologists call “The Blob” pushed temperatures in the eastern Pacific Ocean two degrees Celsius above normal. This warmed every monitored white abalone site in southern California, some of them past the 18-degree threshold. Climate change is expected to routinely bring warmer water temperatures to some stretches of white abalone habitat, potentially eliminating their thermal protection in these areas altogether.
To make matters worse, rising ocean temperatures are also wreaking havoc on the animals’ habitat and food sources. Kelp forests need temperatures between 5 and 20 degrees Celsius (41 and 68 degrees Fahrenheit) to thrive. When water temperatures increase, the amount of dissolved inorganic nitrogen drops, and kelp abundance begins to fall as well.
A Brief History of White Abalone
Thanks to over-harvesting, reproductive failure, and infections, white abalone has gone from abundant to endangered in just half a century. But science has been staging an intervention in hopes of improving the species' odds of survival. Click on the green circles to learn more.
19601970198019902000201020201968White abalone harvest takes off in CaliforniaAt its peak, 144,000 pounds of white abalone is harvested in a year1978White abalone harvest plummets; a mere 3,600 pounds are harvested this year1997California prohibits commercial and recreational fishing of white abaloneWhite abalone numbers at a monitoring site in Tanner Bank, California continue to fall despite protections2002-201419722001White abalone is federally listed as an endangered species
When I meet Jim Moore inside the California Department of Fish and Wildlife’s Shellfish Health Lab, the invertebrate pathologist is peering through a microscope, examining dyed tissue samples taken from captive white abalone. He’s hoping that by documenting the process of necrosis—what an abalone’s tissues do after the animal dies—he’ll be able to sort out the difference between changes caused by pathogenic disease and those that happen naturally after death. “It’s difficult for us to figure out when an abalone is really dead—often once [researchers] realize, it’s been dead for a while,” he says. This makes it hard to know if an infection took hold before the animal died (perhaps causing death) or after.
To keep Withering Foot Syndrome at bay in the nursery, Moore gives the animals a bath in an antibiotic called oxytetracycline and treats them with UV radiation as soon as they arrive. Researchers can douse the animals once more before stocking them in the wild, to protect them from the disease for a few more months, but without continual treatment the abalone are likely to become infected.
In a stroke of evolutionary good fortune, a bacterial phage, or hyper-parasite, emerged a few years ago, fighting off the syndrome in wild populations of black abalone, as well as on red abalone farms in central California. In black abalone, for example, researchers found the phage reduced the infection load in targeted tissue by roughly half. The phage has since spread and is protecting abalone populations throughout their range, wherever the pathogen is found. Moore says researchers have no clue where it came from or how it arrived, but “the enemy of your enemy is your friend,” he says. The phage has shown mixed results to date in saving white abalone, but considering its enigmatic nature, there’s hope that the phage, or another variant, may turn out to provide some level of protection.
Progress has also been made in keeping illegal harvest to a minimum. To pin down poachers, Erin Meredith, senior wildlife forensic specialist for the California Department of Fish and Wildlife’s Wildlife Forensic Laboratory, helped to develop a genetic test to distinguish between red, black, pink, green, flat and white species. Now, when enforcement officers come across suspected abalone poachers in the field, they can take tissue samples from the mollusks and send them to a lab for species identification. Meredith’s test also enables officers to analyze items used in potential poaching activities, such as the suspect’s dive gloves, wetsuits and pry knives—anything that may have come into contact with the abalone. And it’s working. Earlier this year, Meredith received her first case involving potentially poached white abalone in southern California.
The challenge that remains is figuring out how and where to return the captive-bred abalone to the wild once researchers receive federal approval to release them—possibly within the next year. Even if scientists manage to protect abalone from poachers and disease, predators threaten to undo all the gains achieved so far.
The 22-foot Boston Whaler dubbed Kelpfish rolls in the choppy waters off San Diego as pelicans dive like sharpshooters around the boat, snapping up fish and gulping them down quivering gullets that reverberate with each flop. Sea lions and porpoises swim by, taking advantage of the ocean’s bounty. On the horizon, a California Department of Fish and Wildlife enforcement officer patrols the protected waters, on the lookout for possible poachers. But today, most of the action is happening far beneath the waves.
After 45 minutes, a stream of fizzing bubbles rises to the water’s surface, signaling the return of divers Jenny Hofmeister and Arturo Ramirez. The two waterlogged black shapes emerge from a cloud of tuna crabs and weedy kelp and haul themselves from the cool water along with mesh bags filled with a collection of sea creatures. After a quick swig of ginger tea to warm up, Hofmeister begins sifting through her scavenged treasures: an empty cowrie shell; five Kellet’s whelks; a starfish; and a half-dozen red abalone shells, their occupants long-since eaten.
Over the past week, Hofmeister and a team of divers from the Bodega Marine Laboratory have been performing predator surveys in a range of stocked habitat plots along the California coastline. Last year, to test the waters, the team released 3,200 farm-raised red abalone in Long Beach—a process they call outplanting. “We saw a very quick and immediate increase in octopus right next to our abalone a few days after we put them out there,” Hofmeister says. “We call it ‘ringing the dinner bell’.”
Octopuses are abalone’s most voracious predators in deep water, but crabs, lobsters, and fish will target them, too. Captive-bred abalone released into the wild, researchers theorize, are stressed in their new environment and haven’t developed fast-acting fear responses yet. The abalone’s first lines of defense are passive: camouflage and a hard shell. If pursued by a slow-moving predator, like a starfish or predatory snail, abalone can retreat, if only at a literal snail’s pace. When faster-moving threats approach, abalone can engage their mollusk death grip, clamping down on a rock and holding on for dear life. But studies show that farm-raised abalone don’t clamp down fast enough. And even if they do, some predators, like octopuses, are able to bore through their shells.
Hofmeister pulls out her waterproof chart and begins performing casual necropsies on each of the red abalone shells she’s collected. “Damage to the shell can give us an indicator of what ate it,” she says, picking up a tiny green and gray shell with chips along the edge. “This was probably a crab or a lobster, because they’ll use their sharp claws to flip the abalone off the rock.” Octopus kills, she continues, can be identified by the pin-prick-sized hole it makes through the middle of the abalone shell with its rasping tongue to reach the main muscle, where the octopus injects a paralyzing toxin. This allows the octopus to pry the abalone off the rock and devour it. “There is not much we can do to increase the armor of the abalone,” Hofmeister says. "If we can find a way to deter octopus, that might be our best bet.”
So far, about 700 of the 7,200 outplanted red abalone from the trial have been accounted for across nine sites in coastal Los Angeles and San Diego, 400 of them dead and 300 alive. The site Hofmeister is monitoring today seems to be showing better survival rates than other locations as well as fewer predators. As she packages each abalone shell in a small plastic bag, another dive team swings by in their boat and passes over a white plastic bucket containing a California two-spot octopus (Octopus bimaculoides) collected at one of their survey plots.
“A lot of my research is addressing how we can outsmart the octopus,” says Hofmeister as she hoists the slimy, red mollusk from the water in the bucket, already stained with the animal’s defensive ink. She empties the toxic contents over the side of the boat as the octopus suctions tightly to her hand. Because octopuses use their tentacles to “taste” their way along the seafloor, Hofmeister wonders if it would be feasible to coat the abalone’s shell with an unpalatable concoction to deter predators. She explains, “We want a coating that doesn’t hurt the abalone, but if an octopus touches it, he’s like ‘Nope!’” Alternatively, if researchers find areas that octopuses steer clear of—a patch of sandy terrain or rocky relief too unpleasant to traverse—these might be good spots to release white abalone.
Hofmeister pulls out her measuring stick and takes a read of the size of the octopus’s mantle. Then she checks for any physical damage; tentacle R2 is missing its tip, but it will regrow. Last, she sexes the octopus and estimates her to be six months old. By year’s end, she’ll double in size. “Don’t ink, don’t ink, don’t ink,” Hofmeister mutters as she returns the animal back to the bucket of water.
She inks.
By mid-afternoon, our boat is harbor-bound, speeding over dark blue waters. The clouds that hung low throughout the morning have dissipated, and the mansions of San Diego loom large above the shoreline. Mitt Romney has a $12 million beachfront vacation home here, not far from John McCain’s $1 million luxury condo.
One of the biggest challenges of white abalone restoration is getting people to care about an animal that so closely resembles a rock. Abalone are the antithesis of charismatic megafauna. Still, Aquilino is on a mission to make the world see these creatures as both “cute” and vital to the ocean’s health. If people can look past the animals’ hard exterior, they may invest more in saving abalone, which play a critical role in maintaining the nation’s kelp forests and the coastlines these ecosystems hold together.
In this part of southern California, where white abalone have all but disappeared, sea urchin populations have exploded over the past 20 years, forming so-called “urchin barrens.” With no abalone around to compete for habitat and vital resources, urchins move out of subtidal cracks and crevices to mow down kelp and the ecosystems the plants support. In California, it’s these kelp forests that protect coastlines from wave action. “They absorb a lot of the ocean’s energy,” explains Hofmeister. As sea levels rise, waves will likely be able to travel farther inland, even during calm conditions, eroding away land. Storm surges bring larger waves, and with them, the potential to cause catastrophic damage. “Without kelp forests, Romney’s house is going to be gone,” she says.
According to a 2013 study in Nature, if protective nearshore habitats such as kelp forests were lost, we would see a doubling of the number of poor families, elderly people, and property value exposed to coastal hazards like flooding and sea level rise by 2100. And without abalone, kelp forests’ days may be numbered. It’s not just a matter of getting people to acknowledge that abalone are cute; the mollusks provide tangible, measurable economic benefits in the form of coastal protection.
“The kelp forest is an ecosystem that supports a lot of different species,” explains Hofmeister. Remove one of those species, and the whole ecosystem can crumble. When sea otters disappeared in the Aleutian Archipelago in southeast Alaska, for example, urchins exploded and ate all the kelp until the forest disappeared, and with it many of the species it supported, such as seals, sharks, and sea lions. But when sea otters were extirpated in southern California, where other species that preyed on the urchins still existed, the forests remained resilient. “The more biodiverse an ecosystem is, the more resilient it is to change,” Hofmeister says. “Diversity saved the kelp forests then, and diversity is what is going save the kelp forests now.”
Photo credits:
Header: A white abalone at the Bodega Marine Lab. Photograph by John Burgess/The Press Democrat
The Bodega Marine Lab in Horseshoe Cove.
The Shellfish Health Lab.
A dyed sample of diseased abalone tissue.
Homes overlooking the waters of San Diego. Photograph by Gloria Dickie.
Footer: The rocky coast of Northern California.
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As oceans acidify, shellfish farmers respond.
Scientists collaborate to mitigate climate impacts in the Northwest.
Taylor Shellfish Farm’s Quilcene hatchery perches on a narrow peninsula that juts into the sinuous waterways of Washington’s Puget Sound. On the July day I visited, the hatchery and everything surrounding it seemed to drip with fecundity. Clouds banked over darkly forested hills on the opposite shore, and a tangy breeze blew in from across the bay. But the lushness hid an ecosystem’s unraveling.
Climate change is altering the very chemistry of surface seawater, causing ocean acidification, a chemical process that is lowering the amount of calcium marine organisms can access. Acidification is a relative term; the oceans are not actually turning into acid and will not melt surfboards or sea turtles anytime soon. Still, with enough acidification, seawater becomes corrosive to some organisms. Hardest hit are calcifiers, which use aragonite, a form of the mineral calcium carbonate, to make shells, skeletons and other important body parts. Examples of calcifiers include crabs, sea urchins, sea stars, some seaweeds, reef-forming corals, and a type of tiny floating marine snail, or pteropod, called a sea butterfly. Shellfish, including oysters and clams, are also seriously affected. With the disappearance of many of these sea creatures, oceanic food webs will be irrevocably altered by century’s end.
People have harvested shellfish in the Pacific Northwest for thousands of years. Today, the industry generates more than $270 million annually in the state of Washington alone. A decade ago, the region’s shellfish growers were already reeling from harmful effects of climate change, so they have been in some ways at the forefront of climate adaptation. I’d driven to Taylor Shellfish Farm to learn how they were working, with scientists and others, to save their livelihoods and the coastal ecosystems they’re built on.
Dave Pederson, the hatchery manager, met me in a bright building full of burbling saltwater tanks of assorted mollusks. A tall, fit man with a graying beard, Pederson led me outside behind the hatchery. Two hundred feet below us, glittering blue water splashed against the steep cliffside, while inside the hatchery, tiny oysters, mussels and geoducks — pronounced “gooey ducks” — filtered algae soups, carefully concocted by hatchery staff. Yesterday, workers had spawned Pacific oysters, which within hours built their first shells from seawater calcium. Throughout the hatchery, millions of baby bivalves grew from mere specks to identifiable mollusks, fated to gleam on half shells in trendy Seattle oyster bars, or be whisked off to Asia by FedEx flight.
“Oysters are our number-one product, then geoducks, then Mediterranean mussels,” Pederson said, guiding me between shaded storage tanks. “We’ve also done some research work with scallops.”
For more than 250 years, since the Industrial Revolution’s beginnings, the ocean has absorbed approximately a third of the carbon dioxide that humans have produced, slowing the impacts of climate change on land. But since 1750, the average acidity of its surface water has increased by almost 30 percent. The ocean is acidifying 10 times faster now than it has in the past 50 million years. Scientists don’t yet understand what this means for sea life, but ocean acidification already affects Pederson and others who rely on the ocean. He and other farmers, along with researchers and policymakers, are searching for lasting solutions to the regional climate change impacts they are witnessing. Meanwhile, worries about the planetary implications of ocean acidification keep growing.
Humans have lived along North America’s West Coast for millennia, in part because of a maritime phenomenon that occurs in only a few places on Earth: seasonal coastal upwelling. First, surface seawater near Japan sinks into a deep-water current well below sunlight. That current carries the water to North America, a trip that takes between 30 and 50 years. Decaying pieces of marine plants and animals come along for the ride, providing a feast for carbon dioxide-releasing bacteria that naturally acidify the surrounding water. Eventually, this deep current reaches the West Coast, where a southerly wind blows the surface water out to sea. Then the nutrient-rich water from the North Pacific rises, nourishing the seaweed and phytoplankton that thrive in sunlit surface waters. That growth is the foundation for the West Coast’s incredibly diverse food web, which supports some of the most productive fisheries in the world.
Even before human-caused climate change, the organisms of the Pacific Northwest lived at the edge of their tolerance for acidity. Now, though, surface water absorbs so much atmospheric carbon dioxide that by the time it upwells again, its acidification will reach problematic levels.
“This is something that’s roaring up on us that can’t be stopped and is really kind of freaky-scary,” Skyli McAfee, director of The Nature Conservancy’s North American Oceans Program, told me. “We know that we already had an unusual and acidified system, and to pile all this on top of it — we’re not certain what kind of impacts we can expect to see.”
Because of the long voyage that Pacific seawater takes, this problem won’t stop anytime soon, McAfee added. “Even if we stopped all carbon emissions tomorrow, we’d be getting the signals that have already been entrained in the water, over the next several decades,” she said. “Twenty years from now, we’re going see waters that contain a signal from the atmosphere 20 years ago. So we kind of bought the cow.”
The study of ocean acidification is still a young field, and scientists don’t yet know how the phenomenon is going to affect most sea life. But in coastal areas, it’s clearly compounding other threats, such as farming pollution and city sewage. To McAfee, this introduces a paradoxical sliver of hope: If regional actions exacerbate a globally produced problem, perhaps regional responses can help assuage it. McAfee acknowledged that there is no returning to an ocean untouched by human-caused acidification. Instead, she focuses on resilience. As more people move into coastal communities, more and more nutrients flush into coastal systems. Extra municipal and agricultural runoff create the potential for more “dead zones,” such as in the Gulf of Mexico. “It sets off a chemical reaction that is analogous to ocean acidification,” McAfee said. McAfee believes that coastal communities can protect themselves by keeping their marine ecosystems as healthy and diverse as possible, helping to prepare for ever-more-acidic upwellings. This will require working with farms and cities to cut back on runoff, for example, and preserving as many coastal protected areas as possible to give marine life safe places to grow from vulnerable babies into adults. Ultimately, if coastal ecosystems get help with regional stressors, they will be in the best possible shape for surviving global stressors. McAfee calls this “managing for resilience.”
“It’s not all doom and gloom,” she assured me. “At the end of the day, what the story is, is: We have the tools, we have the science, we have the fortitude. We just need to do it.”
decade ago, most people — including scientists and shellfish growers — had never heard of ocean acidification. But in 2007, following a hunch, National Oceanic and Atmospheric Administration oceanographer Richard Feely put to sea on a research trip off the West Coast of North America. Feely had found dissolved carbon dioxide levels in surface waters of the continental shelf off Northern California that were much higher than he’d expected. While Feely thought those high recordings hinted that an upwelling event was happening, he had no idea of the magnitude or extent of the acidification he was about to discover.
Feely assembled a group of marine researchers who sailed from Canada to Mexico, collecting and analyzing water samples along the way. They had a bet going about when they would see ocean acidification. All of them turned out to be wrong, because it was everywhere: Corrosive waters registered from Vancouver Island all the way to Baja California. Feely and his colleagues estimated that by the end of the century, marine creatures throughout the entire ocean would have access to dramatically less calcium carbonate because of ocean acidification, with regions of coastal upwelling hit especially hard.
Even as Feely conducted his 2007 cruise, shellfish farms throughout the Pacific Northwest were failing. About two days after hatching, all 2 million oysters in a set would die. Whiskey Creek hatchery — one of the industry’s largest suppliers of shellfish larvae to farms — produced only 2.5 billion “eyed” larvae in 2008, just 25 percent of what it normally produced in a season. As one bad season stretched into two, farmers focused on the usual suspects. Thinking a bacterium called Vibrio tubiashii was to blame, growers would halt operations, clean out their tanks, and add new water and new stock, only for their oysters to die again. The growers were mystified. Then, in 2008, Feely and the other researchers published their findings. Later that year, the Pacific Shellfish Growers Association invited Feely to present his research at its annual meeting. The reality, the growers learned, was much worse than a common bacterium: Essentially, as their baby oysters struggled to pull enough calcium from acidified seawater to form shells, they ran out of energy and starved to death.
Greg Dale, southwest operations manager at Coast Seafoods Company in Northern California, watched Feely’s presentation. Raised in a fishing family from Alaska, Dale began working at an oyster farm as a student at Humboldt State University. At first, it was just a job, but he ended up loving the work. At Coast Seafoods, Dale raised oysters both to sell as baby “seeds” and as ready-to-eat adults. The adults were transferred to tidal mudflats, where they grew individually in baskets of powdered shell, or on pieces of shell stuck in braids of rope that trail up from the bottom of the ocean like underwater vineyards. For two terrible years, though, Dale’s oyster seeds died before they ever left their tanks. In some cases, their tiny shells seemed to dissolve.
Feely’s keynote presentation explained what Dale and the other growers were witnessing at their hatcheries: Before the Industrial Revolution, the upper ocean’s average pH was 8.2. The pH scale, which measures acidity, goes down as acidity goes up. It’s now 8.1, a deceptively small-sounding difference: The ocean is actually 30 percent more acidified. And in the summer of 2008, because of seasonal upwelling, hatcheries recorded seawater pH levels as low as 7.6, which explained the havoc shellfish farms were experiencing. If carbon dioxide emissions continue increasing as predicted, by the end of this century the ocean’s surface may become on average 150 times more acidified than it was before the Industrial Revolution, with a pH of about 7.8. This would be disastrous for a lot of marine life, especially in areas such as the Pacific Northwest.
Word of the researchers’ findings spread. Pacific shellfish growers quickly went to work with state and federal biologists to adapt, so their stock could survive in a changing ocean. They tried filling their water tanks in the afternoon, rather than the morning; this improved the baby oysters’ chances of survival because photosynthesizing plants took up some of the seawater’s carbon dioxide. Shellfish continued to die, but there was enough improvement to suggest that things were headed in the right direction. Next, researchers put the same pH and carbon dioxide sensors they had had on their ship into hatcheries. Scientists also taught farmers how to add calcium carbonate — soda ash — to seawater coming into their hatcheries, raising the pH in tanks. Hatcheries even shortened their spawning season to avoid the acidified late-summer conditions of the sound.
Scientists and farmers were able to work together because Sen. Maria Cantwell, a Democrat from Washington, supported their collaboration. “She secured $500,000 of stimulus money to buy pH sensors and put them into the hatcheries,” Feely said. “So for that $500,000 investment, we saved that industry from dying off. We saved that industry $35 million in one year’s time. That’s a clear example of how science and government can work together to save an industry, and that felt pretty good.”
Which is not to say that the tools they used were pretty. Tracking the measurements that shellfish growers rely on — such as carbon dioxide levels and aragonite saturation levels — in real time is complicated. Burke Hales, an oceanographer with Oregon State University, constructed a device, resembling a plastic travel trunk sprouting machinery and colored wires, that hatcheries could install to monitor conditions. Now, when conditions are bad, growers don’t spawn oysters. The co-owner of another hatchery named the contraption, which has since been trademarked, the Burke-o-lator.
The economic calamity caused by ocean acidification in 2007 and 2008 caught the attention of many people, including then-Washington Gov. Christine Gregoire. Washington’s seafood industry generates more than 42,000 jobs and $1.7 billion a year, from industry profits and employment at neighborhood seafood restaurants, distributors and retailors. What’s more, shellfish have significant and growing cultural and resource value for the region’s tribal communities, especially as salmon stocks plummet. Gregoire created the Washington State Blue Ribbon Panel on Ocean Acidification in 2011. Five years later, the panel would become the springboard for the International Alliance to Combat Ocean Acidification, which has united local, tribal and national governments from around the world, though the U.S. government has yet to join.
Today, the Pacific shellfish industry is at 50 to 70 percent of historic production levels. “We’re all really freaked out about ocean acidification,” Dale said. “What we realized is that it’s not going to change in our lifetime — the causes of acidification — so what we want is tools to manage around it.” For the past decade, NOAA provided many of those tools through its Integrated Ocean Observing System, or IOOS. But research and management programs depend on the political climate as well as the physical one. As NOAA funding has decreased, Pederson told me, scientists have come to rely more on industry data. A graduate student conducting research at the Quilcene hatchery showed me a Burke-o-lator in a cramped plastic shed. The device was broken, and hatchery personnel had neither the time nor expertise to fix it. Hales, I was told, was working to create a new version that was more mobile, user-friendly and affordable.
Because of ocean acidification, multiple Pacific Coast hatcheries have tried relocating their operations to Hawaii, though they’ve struggled there as well. Some hatcheries are researching another approach: selectively breeding oysters that are more tolerant of lower pH levels. It’s possible, too, that growing shellfish near seaweeds and seagrasses — which take up carbon dioxide — could help. I spoke with two senior scientists — one in California, one in Washington — who have experimented with growing kelp and are now analyzing their results. But it may take years before researchers know whether planting kelp in coastal waters helps. There are no easy solutions to ocean acidification for the shellfish industry. In the meantime, as acidity levels increase, shellfish become ever more vulnerable. Right now, only baby shellfish struggle in the Eastern Pacific’s acidifying waters, but eventually, adult shellfish may, too.
Of course, the ocean holds much more than shellfish. Oysters, however fascinating, tasty or economically important, comprise a very small part of the sea’s life at the end of the day. “It’s honestly quite scary,” Dale said. “The ocean drives everything — the whole food web, our weather, clouds.” Neither is acidification the only climate-change-related concern; rising sea levels, warming ocean temperatures and hypoxia complicate life for coastal communities even more. Dale mentioned the “Blob,” a huge, persistent patch of unusually warm water that lingered off the West Coast from 2013 until 2016. “That really just drove everything into the ground,” he said. “Our salmon, harmful algal blooms, birds starving. The ocean is just goofy right now.”
It was an overcast Thursday dawn when I boarded the Clifford A. Barnes, a 65-foot research vessel anchored in a Puget Sound marina. “Cliffy,” as the ship is affectionately called, belongs to the National Science Foundation. As I stumbled onboard, most of the crew, led by Chief Scientist Marine Lebrec, who wore green waterproof boots and a sky-blue down jacket against the chill morning air, were hustling to cast off or hunched silently in the small galley over phone screens and steaming mugs. Under the captain’s watchful eye, Cliffy quietly motored out of the dock and into the mist rising from the slate-colored waters.
Later, when we were underway and caffeinated, the researchers — who were living onboard in cramped bunk beds — began their grueling routine of hauling in sampling gear and nets at mapped locations, rushing to preserve and process samples, and resetting the gear for the next stop. In between, they showed me what they’d gathered from the sea: assemblages of tiny crustaceans to be sorted, pteropods to be checked for corrosion, water to be analyzed for everything from dissolved oxygen content to chlorophyll levels, crabs for dinner. A pair of bald eagles gripping the bare branches of a snaggled tree passed on our starboard side; two dolphins swam in our wake. The water that Cliffy nosed through turned teal blue, provoking excited speculations about a “coccolithophore” — a one-celled phytoplankton — bloom. “I haven’t seen this in 40 years of sampling here,” one researcher told the others.
Much of the collecting was on behalf of researchers not present; the boat bunked only six, with two spots reserved for undergraduate volunteers. The scramble to collect everything at each stop didn’t let up, even when a cold, steady rain began. For lunch, researchers slipped into the galley briefly in ones and twos and slapped together thin sandwiches, then ducked back into the lab built on the deck. Washington Ocean Acidification Center, or WOAC, research cruises ply Puget Sound three times a year, collecting water chemistry data and dragging plankton tows, a combined effort to study chemical cause and biological effects of ocean acidification.
On this cruise, postdoctoral student Ramón Gallego collected floating DNA samples, or eDNA, from the water to find out what had passed by recently for a new collaboration combining that data with ocean acidification research. “We think that areas with less ocean acidification will have more species richness,” he said. Gallego used a preservative to kill any living organism in the water sample, so that small microscopic bits of life didn’t eat the even smaller bits before he’d had a chance to analyze them. Originally from the Canary Islands, Gallego spent several years in Madrid in mainland Spain during his 20s. “I don’t want to live away from the ocean anymore,” he said.
The biology of ocean acidification is a new field, though it’s growing quickly. Laboratory studies of ocean acidification reveal direct and negative consequences on larval mollusks and juvenile fish, but things get complicated in the field. Terrie Klinger, co-director of WOAC, focuses on the biological consequences of ocean acidification. “The chemical evidence of acidification is unequivocal,” she told me by phone from her Seattle office. Still, “it’s very difficult to do lab studies on multiple species at one time and then have them bear any resemblance to what happens in nature.” Some of the most surprising discoveries have come from observing juvenile fish. A research group in Australia first noticed that juvenile fish behave strangely in acidified water. Ocean acidification affects a particular neuroreceptor in the fish that is sensitive to carbon dioxide levels — a receptor that’s found in virtually all vertebrate species. With increased acidification, “fish are less able to smell their predators,” Klinger said. “They are sometimes less able to smell food; they don’t eat as well. In coral reef habitats where they have very strong homing behaviors to crevices, they can lose their homing behavior.”
Funding limitations hamper biological monitoring, even though researchers must study complicated factors in combination: marine species reacting to changes in pH and temperature and hypoxia together, for example, or looking at more than one organism at a time in the field, which is tricky. WOAC funds laboratory experiments on the effects of ocean acidification on salmon, black cod, crab, copepods, euphausiids, oysters and other Washington species. Still, “we’re limited in what we can do at this time,” Klinger admitted. Because it’s very difficult to do lab studies that resemble the natural world, some of the best studies from the field come from underwater seeps. Just by chance, the natural carbon dioxide leaking from underwater volcanoes into seawater mimics the expected change in pH due to ocean acidification. When carbon dioxide levels cause enough acidification at a seep, the area becomes overgrown by seaweeds, and animals disappear.
Back on Cliffy, as the sun broke through, crewmembers stripped off their rainclothes. Expensive vacation homes began to dot woodsy hillsides, glowing in the late afternoon light. Everyone looked forward to the end of the workday, when Cliffy would dock at the only place the researchers would be able to shower for the entire voyage: an extremely expensive resort, some of whose guests arrived by seaplane and private yacht. I wondered how much the guests in that idyllic setting understood about the biogeochemical processes happening around them — because of them. Because of all of us: Perhaps a small quantity of the carbon dioxide that acidified these waters emerged from the tailpipe of the moving truck that my parents drove from New York City to my New Mexico birthplace some 40 years ago.
The fate of the oceans can’t easily be predicted, but ominous signs are floating all around us. You could scoop up some of the most telling into your hands, but they are so small they would drip through your fingers without your noticing. In a rare moment of downtime toward the end of the cruise, scientist Natasha Christman showed me image after image taken by scanning electron microscope of tiny coiled shells in different stages of dissolution. Microscopic planktonic snails with body parts like wings, pteropods — or sea butterflies — are as delicate and beautiful as their name suggests. Pteropods are exceedingly sensitive to acidification, so researchers use them as indicators. In extra-acidified water, the small snails don’t die right away. Instead, they crumble, exhausting their resources trying to repair their shells. By 2050, as much as 70 percent of the pteropods on the outer continental shelf may be destroyed by upwelling events, up from about 50 percent currently. Before the Industrial Revolution, upwelling events harmed only about 11 percent of pteropods, which form the basis of a marine food web that includes everything from seabirds to Pacific salmon.
The day before the cruise, I’d met with Jan Newton, the other co-director of WOAC, at her University of Washington office, a fifth-story room warmed by the late sun angling through a bank of windows. Tall, with clear frameless glasses on an open face, Newton had her long gray hair pulled loosely into a ponytail. At the start of the interview, she paused to scan her smartphone for photos of her new grandchild. “What I love about oceanography is that large system,” she said. “I’m thinking about global atmospheric processes as well as down on a cellular level, and integrating all of that. I just love that.” Though the walls of Newton’s office were plastered with research posters and she had two desktop computer monitors in addition to a laptop, the many freckles on her arms testified to long hours spent on the water. “There’s a real joy, I think, to studying natural systems,” she said. “Now ocean acidification is just this really horrible situation, but what’s interesting about studying ocean acidification is you have to understand everything to understand it.”
Because ecological knowledge about ocean acidification is in its infancy, solutions-based endeavors are, too. But there’s a growing enthusiasm for finding those solutions. Newton also focuses on refining the information that WOAC provides to shellfish growers. She wants them to be able to look up acidification predictions for their localities on their smartphones as easily as they do weather predictions. “Knowledge is enabling,” she said.
I wondered, at this point, what she hoped this knowledge would enable people to do. I felt personally overwhelmed by ocean acidification, and we’d only been discussing it for about an hour; it was her life’s work. “I carry a responsibility to make sure people understand it more, because it does have implications for generations on down,” she responded. “The more that people see what the response of what we’re doing is, the more they can make decisions. I feel like when I give a talk on (acidification), it’s just so depressing, and people go, ‘Well it’s just going to happen, and we’re screwed.’ But which world would you rather live in? We are actively making that choice every day as a global community.”
Regional solutions necessary require triage. The ocean might recover on its own from ocean acidification through slow planetary processes: the weathering of rocks and dissolving of calcium carbonate in marine sediments, mixed into sea water by ocean circulation patterns but this would take up to hundreds of millennia.
After we docked Cliffy and ate freshly boiled crabs — cracked open with pliers from a toolkit, so sweet we skipped the butter — I joined the crew in walking to the resort, where they would shower and have a drink and I could text a cab for the long drive back up Puget Sound. On the way to the resort’s outdoor bar, we passed a wedding party gathered on a green lawn that stretched to the water’s edge. The adults chatted and laughed together over drinks in the setting sun. A few small children clambered over a stone walkway to the beach, where they crouched in the fading light, picking through the rocks in search of shells.
Maya L. Kapoor is an associate editor with HCN. She writes about science and the environment in the urbanizing West.
This story was funded with reader donations to the High Country News Research Fund.
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Where's the kelp? Warm ocean takes toll on undersea forests.
The likely culprit for the loss of kelp, according to several scientific studies, is warming oceans from climate change, coupled with the arrival of invasive species.
By MICHAEL CASEY, ASSOCIATED PRESS APPLEDORE ISLAND, Maine — Aug 22, 2017, 1:01 AM ET
When diving in the Gulf of Maine a few years back, Jennifer Dijkstra expected to be swimming through a flowing kelp forest that had long served as a nursery and food for juvenile fish and lobster.
But Dijkstra, a University of New Hampshire marine biologist, saw only a patchy seafloor before her. The sugar kelp had declined dramatically and been replaced by invasive, shrub-like seaweed that looked like a giant shag rug.
"I remember going to some dive sites and honestly being shocked at how few kelp blades we saw," she said.
The Gulf of Maine, stretching from Cape Cod to Nova Scotia, is the latest in a growing list of global hotspots losing their kelp, including hundreds of miles in the Mediterranean Sea, off southern Japan and Australia, and parts of the California coast.
Among the world's most diverse marine ecosystems, kelp forests are found on all continental coastlines except for Antarctica and provide critical food and shelter to myriad fish and other creatures. Kelp also is critical to coastal economies, providing billions of dollars in tourism and fishing.
The likely culprit for the loss of kelp, according to several scientific studies, is warming oceans from climate change, coupled with the arrival of invasive species. In Maine, the invaders are other seaweeds. In Australia, the Mediterranean and Japan, tropical fish are feasting on the kelp.
Most kelp are replaced by small, tightly packed, bushy seaweeds that collect sediment and prevent kelp from growing back, said the University of Western Australia's Thomas Wernberg.
"Collectively these changes are part of a recent and increasing global trend of flattening of the world's kelp forests," said Wernberg, co-author of a 2016 study in the Proceedings of the National Academy of Sciences, which found that 38 percent of kelp forest declined over the past 50 years in regions that had data.
Kelp losses on Australia's Great Southern Reef threaten tourism and fishing industries worth $10 billion. Die-offs contributed to a 60 percent drop in species richness in the Mediterranean and were blamed for the collapse of the abalone fishery in Japan.
"You are losing habitat. You are losing food. You are losing shoreline protection," said University of Massachusetts Boston's Jarrett Byrnes, who leads a working group on kelp and climate change. "They provide real value to humans."
The Pacific Coast from northern California to the Oregon border is one place that suffered dramatic kelp loss, according to Cynthia Catton, a research associate at the Bodega Marine Laboratory at the University of California, Davis. Since 2014, aerial surveys have shown that bull kelp declined by over 90 percent, something Catton blamed on a marine heat wave along with a rapid increase in kelp-eating sea urchins.
Without the kelp to eat, Northern California's abalone fishery has been harmed.
"It's pretty devastating to the ecosystem as a whole," Catton said. "It's like a redwood forest that has been completely clear-cut. If you lose the trees, you don't have a forest."
Kelp is incredibly resilient and has been known to bounce back from storms and heat waves.
But in Maine, it has struggled to recover following an explosion of voracious sea urchins in the 1980s that wiped out many kelp beds. Now, it must survive in waters that are warming faster than the vast majority of the world's oceans — most likely forcing kelp to migrate northward or into deeper waters.
"What the future holds is more complicated," Byrnes said. "If the Gulf of Maine warms sufficiently, we know kelp will have a hard time holding on."
On their dives around Maine's Appledore Island, a craggy island off New Hampshire that's home to nesting seagulls, Dijkstra and colleague Larry Harris have witnessed dramatic changes.
Their study, published by the Journal of Ecology in April, examined photos of seaweed populations and dive logs going back 30 years in the Gulf of Maine. They found introduced species from as far away as Asia, such as the filamentous red seaweed, had increased by as much 90 percent and were covering 50 to 90 percent of the gulf's seafloor.
They are seeing far fewer ocean pout, wolf eel and pollock that once were commonplace in these kelp beds. But they also are finding that the half-dozen invasive seaweeds replacing kelp are harboring up to three times more tiny shrimp, snails and other invertebrates.
"We're not really sure how this new seascape will affect higher species in the food web, especially commercially important ones like fish, crabs and lobster," said Dijkstra, following a dive in which bags of invasive seaweed were collected and the invertebrates painstakingly counted. "What we do think is that fish are using these seascapes differently."
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