Advancing ocean acidification biology using Durafet® pH electrodes
October 12, 2017
Kapsenberg L., Bockmon E. E., Bresnahan P. J., Kroeker K. J., Gattuso J.-P. & Martz T. R., 2017. Advancing ocean acidification biology using Durafet® pH electrodes. Frontiers in Marine Science 4:321. doi: 10.3389/fmars.2017.00321. Article.
Research assessing the biological impacts of global ocean change often requires a burdensome characterization of seawater carbonate chemistry. For laboratory-based ocean acidification research, this impedes the scope of experimental design. Honeywell Durafet® III pH electrodes provide precise and continuous seawater pH measurements. In addition to use in oceanographic sensor packages, Durafets can also be used in the laboratory to track and control seawater treatments via Honeywell Universal Dual Analyzers (UDAs). Here we provide performance data, instructions, and step-by-step recommendations for use of multiple UDA-Durafets. Durafet pH measurements were within ±0.005 units pHT of spectrophotometric measurements and agreement among eight Durafets was better than ±0.005 units pHT. These results indicate equal performance to Durafets in oceanographic sensor packages, but methods for calibration and quality control differ. Use of UDA-Durafets vastly improves time-course documentation of experimental conditions and reduces person-hours dedicated to this activity. Due to the versatility of integrating Durafets in laboratory seawater systems, this technology opens the door to advance the scale of questions that the ocean acidification research community aims to address.
Coastal Researchers, Fishermen Worried About More Frequent Low Oxygen Zones
October 7, 2017
Olympic Coast National Marine Sanctuary research team members, Kathy Hough and LTJG Alisha Friel, recover sensors deployed seasonally off the coast of Washington from the research vessel Tatoosh in July 2017. — S. Maenner / NOAA
Scientists in Oregon and Washington are noticing a disruptive ocean phenomenon is becoming more frequent and extreme. It involves a suffocating ribbon of low oxygen seawater over our continental shelf.
It seemed to marine ecologist Francis Chan like this is happening most every summer lately. So the Oregon State University researcher looked back as far as coastal oxygen readings go—to about 1950—to see if it’s always been this way.
“The ocean starting in 2000 really looked different from the ocean we had between the 1950s and 1990s,” Chan said.
Chan said climate change could affect oxygen levels via disrupted circulation and ocean warming. A September storm flushed away this year’s low oxygen zone by churning Northwest coastal waters. But Chan described the severity of the low oxygen readings recorded this summer as among the worst ever observed locally.
“It’s very much a patchy ribbon,” he said from his post in Newport, Oregon. Marine surveys and fixed instruments recorded notably low oxygen values from south of Yachats up past Newport.
Ten oceanographic moorings deployed by the Olympic Coast National Marine Sanctuary also found very low (hypoxic) oxygen values between Cape Elizabeth and Cape Flattery, Washington, this summer.
“This is not a happy year for organisms out on the coast,” said Jenny Waddell, the marine sanctuary’s research coordinator.
Waddell added that at least one sensor dipped into anoxic conditions, “where there’s literally no oxygen.”
“We had indications of a relatively persistent hypoxia event along the Quinault Reservation coastline,” wrote marine scientist Joe Schumacker of the Quinault Department of Fisheries in an email Friday. “Dead fish and shellfish at various locations and times beginning near the end of July and extending through most of August.”
More frequent and severe near-shore hypoxia concerns fishermen and crabbers. Commercial harvesters face reduced catches and economic losses when crabs suffocate and fish and prawns flee the oxygen-starved waters.
One of the tip-offs to OSU researchers of the onset of low oxygen conditions this summer was when Oregon Department of Fish and Wildlife biologists monitoring crab populations noticed crabs dying from lack of oxygen in a research trap. Other observers noted crabs leaving the ocean to seek more oxygenated waters in coastal estuaries and bays.
Earlier this year, researchers and fishery advocates found a receptive ear at the Oregon Legislature when they presented their concerns about silent changes in the ocean. Legislators approved the creation of a new council to be co-chaired by the state Fish and Wildlife director and an OSU leader.
The council is tasked with recommending and coordinating a long-term strategy to address hypoxia as well as ocean acidification.
What scientists are learning about the impact of an acidifying ocean
October 4, 2017
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.”
Matthew O. Berger, NewsDeeply, 2 October 2017. Article.
New Puget Sound species database aids ocean acidification research
Contributed by Michael Milstein
A new study by NOAA Fisheries scientists has produced a detailed, searchable database of almost 3,000 species found in Puget Sound, and unravels some earlier assumptions about how vulnerable some species may be to ocean acidification.
The research published recently in the online journal Elementa finds that contrary to expectations, whether or not an organism builds a shell may not be the best indicator of whether a species is sensitive to ocean acidification. The research also found that how scientists summarize information on species sensitivity to ocean acidification can affect their very understanding of species vulnerability. This finding may put previous studies in new perspective, suggesting that some reviews may overestimate the sensitivity of species to ocean acidification, said Shallin Busch of the Northwest Fisheries Science Center and Ocean Acidification Program in Seattle and lead author of the new research.
Oceans absorb excess carbon dioxide produced by human activities from the atmosphere, and increase in acidity as their carbon dioxide levels increase. Ocean acidification is more pronounced along the Northwest Coast of the United States because of strong upwelling and other factors, both natural and human caused.
The research raises cautions about the assumption that shell-building organisms are more vulnerable to ocean acidification than others, Busch said. The assumption may overlook the sensitivity of species like sharks and fish that do not build shells but could be affected in other ways.
“You really have to look at the individual species’ sensitivity to understand how acidification may affect it,” Busch said. “Dissolving snail shells are an effect of acidification that’s easy to understand, but more subtle changes to the development, physiology, or behavior of marine species like crabs and fish are really important, too.”
As part of the study, Busch and fellow researcher Paul McElhany categorized almost 3,000 Puget Sound species based on their taxonomy and the type of crystal minerals they use to build their shells or skeletons. The details are included in a freely available, searchable online species database for Puget Sound. The database will be useful to other scientists as well as fishermen, divers and citizen scientists for everything from species identification to climate change studies.
“For hundreds of years, scientists have seen species catalogs as a foundation for studies of the natural history of an area,” Busch said. “There is strong value in studying natural history from a number of perspectives.”
A new study catalogs nearly 3,000 Puget Sound species based on their vulnerability to ocean acidification, finding that even species that do not build shells may be at risk in other ways. Kelp forests are home to a diversity of species. Credit: Greg Williams/NWFSC
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.
Geoducks by the millions grow in specially formulated algae mix and protected from acidified ocean water at the Taylor Shellfish Farm hatchery in Quilcene, Washington. — Naomi Tomky
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.”
A 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.
A pinhead-sized pteropod, its shell corroded by ocean acidification, seen through a scanning electron microscope. Pteropods form the basis of a marine food web that includes everything from seabirds to Pacific salmon. — Courtesy Natasha R. Christman/ Washington Ocean Acidification Center
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.
Pacific oyster larvae from Taylor Shellfish Farms. Shellfish develop normally in low dissolved carbon dioxide levels, left. In high dissolved carbon dioxide levels, right, seawater becomes acidified. Shellfish struggling to pull enough calcium from seawater for shell formation run out of energy and starve to death. — Oregon State University College of Earth, Ocean and Atmospheric Sciences, NFCC
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.