Dungeness crab larvae already showing effects of coastal acidification

This infographic shows the location of larval Dungeness crab sampling in 2016, examples of impacts from ocean acidification, as well as photos of a larval (left) and adult (right) crab. Credit: Nina Bednarsek, SSCWRP.

A new NOAA-funded study has documented for the first time that ocean acidification along the US Pacific Northwest coast is impacting the shells and sensory organs of some young Dungeness crab, a prized crustacean that supports the most valuable fishery on the West Coast.

Analysis of samples collected during a 2016 NOAA research cruise identified examples of damage to the carapace, or upper shell, of numerous larval Dungeness crabs, as well as the loss of hair-like sensory structures crabs use to orient themselves to their surroundings.

The study was published in the journal Science of the Total Environment.

Impacts to wild crab mirror results of laboratory study

Prior to this study, scientists thought that Dungeness crab were not vulnerable to current levels of ocean acidification, although a laboratory study conducted on Dungeness crab larvae by NOAA’s Northwest Fisheries Science Center in 2016 found that their development and survival suffered under pH levels expected in the future.

“This is the first study that demonstrates that larval crabs are already affected by ocean acidification in the natural environment, and builds on previous understanding of ocean acidification impacts on pteropods,” said lead author Nina Bednarsek, senior scientist with the Southern California Coastal Water Research Project. “If the crabs are affected already, we really need to make sure we start to pay much more attention to various components of the food chain before it is too late.”

What is ocean acidification?
Ocean acidification refers to a reduction in the pH of ocean water, primarily caused by the uptake of carbon dioxide from the atmosphere over long time spans. When CO2 is absorbed by seawater, a series of chemical reactions occur resulting in the increased concentration of hydrogen ions. This increase causes the seawater to increase its acidity and causes carbonate ions to be less abundant.

Carbonate ions are an important building block of structures such as sea shells and coral skeletons that rely on using calcium carbonate for structural growth. Decreases in carbonate ions can make building and maintaining shells and other calcium carbonate structures difficult for calcifying organisms such as oysters, clams, sea urchins, crabs, corals, and some kinds of shelled plankton, such as pteropods.

Close examination reveals patterns of damage
In this study, examination under a high-magnification, scanning electron microscope revealed that the corrosive conditions of coastal waters had affected portions of the fragile, still-developing external shell and legs of the tiny, almost translucent post-larval Dungeness crabs, leaving tell-tale features, such as abnormal ridging structures and scarred surfaces. This could, in turn, impair larval survival by altering swimming behaviors and competence, including the ability to regulate buoyancy, maintain vertical position, and avoid predators.

One of the more important findings of this study was that crabs showing signs of carapace dissolution were smaller than other larvae. This was disconcerting, scientists said, because the damage during the crab’s larval stages could cause potential developmental delays that could increase energy demands and interfere with maturation.

Sensory organ damage seen for the first time
In a surprising discovery, the team found that the low pH water in some coastal areas damaged the canals where hair-like bristles called mechanoreceptors stick out from the shell. These receptors transmit important chemical and mechanical sensations to the crab, and may help crabs navigate their environment. Examination showed that carapace dissolution destabilizes the attachment of the mechanoreceptor anchor, resulting in them falling out in some individuals.

This is a new aspect of crustacean sensitivity to ocean acidification that has not been previously reported. The team hypothesize that the absence or damage of mechanoreceptors within their neuritic canals may in part explain potential aberrant behavioral patterns, such as slower movement, less tactile recognition, and prolonged searching time, as well as impaired swimming, that have been observed in various crustacean species exposed to low pH conditions in laboratory settings.

“We found dissolution impacts to the crab larvae that were not expected to occur until much later in this century,” said Richard Feely, Senior Scientist with NOAA’s Pacific Marine Environmental Laboratory and one of the co-authors of the study.

Combining observations and modelling work, the research team, which included scientists from JISAO, NOAA’s cooperative institute at the University of Washington, from the University of Connecticut, and from Quebec, Britain and Slovenia, demonstrated that the impacts of dissolution were the most severe in the coastal habitats, where crabs grow and mature.

Previous research has indicated that Dungeness crab may also be vulnerable to future declines due to lack of availability of prey – including bivalves such as clams and other bottom-dwelling invertebrate species.

More research needed
Bednarsek emphasized that more research will be needed to determine whether the external dissolution seen in crabs at this early life stage could carry over into later life stages, including the reproductively active adult stage, and what the potential consequences may be for the population dynamics.

“If these larval crab need to divert energy to repair their exoskeletons, and are smaller as a result, the percentage that make it to adulthood will be at best variable, and likely go down in the long-term,” she said.

Ocean acidification is a major concern for West Coast fishery managers, said Rich Childers, Washington Department of Fish and Wildlife’s ocean acidification policy lead. “These data and results give state and tribal fishery managers and policy makers information that’s vital for harvest and conservation planning.”

The research was supported by the NOAA’s Ocean Acidification Program and NOAA’s Pacific Marine Environmental Laboratory.

NOAA Research News, 23 January 2020. Article.

Original post: https://news-oceanacidification-icc.org/

Quantifying sensitivity and adaptive capacity of shellfish in the Northern California Current Ecosystem to increasing prevalence of ocean acidification and hypoxia

The severity of carbonate chemistry changes from ocean acidification is predicted to increase greatly in the coming decades, with serious consequences for marine species-­ especially those reliant on calcium carbonate for structure and function (Fabry et al. 2008). The Northern California Current Ecosystem off the coast of US West Coast experiences seasonal variations in upwelling and downwelling patterns creating natural episodes of hypoxia and calcite/aragonite undersaturation, exacerbating global trends of increasing ocean acidification and hypoxia (OAH) (Chan et al. 2008) (Gruber et al. 2012). The goal of these experiments was to identify thresholds of tolerance and attempt to quantify a point at which variance in responses to stress collapses. This study focuses on two species: Cancer magister (Dungeness crab) and Haliotis rufescens (red abalone). These species were selected for this study based on their economic and ecological value, as well as their taxonomic differences. Respirometry was used as a proxy for metabolic activity at four different scenarios mimicking preindustrial, upwelling, contemporary upwelling, and distant future conditions by manipulating dissolved oxygen and inorganic carbon (DIC) concentrations. Both species showed a decrease in mean respiration rate as OAH stressors increase, including an effect in contemporary upwelling conditions. These results suggest that current exposure to ocean acidification (OA) and hypoxia do not confer resilience to these stressors for either taxa. In teasing apart the effects of OAH as multiple stressors, it was found that Dungeness crab response was more strongly driven by concentration of dissolved oxygen, while red abalone data suggested a strong interactive effect between OA and hypoxia. Not only did these two different taxa exhibit different responses to a multiple stressors, but the fact that the Dungeness crab were secondarily impacted by acidification could suggest that current management concerns may need to be focus more strongly on deoxygenation.

Gossner H. M., 2018. Quantifying sensitivity and adaptive capacity of shellfish in the northern California current ecosystem to increasing prevalence of ocean acidification and hypoxia. MSc thesis, Oregon State University, 104 p. Thesis.

Original post: https://news-oceanacidification-icc.org/

Consequences of spatially variable ocean acidification in the California Current: Lower pH drives strongest declines in benthic species in southern regions while greatest economic impacts occur in northern regions

Emma E. Hodgson^a, Isaac C. Kaplan^b, Kristin N. Marshall^c, Jerry Leonard^c, Timothy E. Essington^a, D. Shallin Busch^d, Elizabeth A. Fulton^{e, f}, Chris J. Harvey^b, Albert Hermann^{g, h}, Paul McElhany^b

• ^a School of Aquatic and Fishery Sciences, University of Washington, Seattle, WA 98195-5020, USA
• ^b Conservation Biology Division, Northwest Fisheries Science Center, National Marine Fisheries Service, NOAA, 2725 Montlake Blvd E, Seattle WA 98112, USA
• ^c Fishery Resource Analysis and Monitoring Division, Northwest Fisheries Science Center, National Marine Fisheries Service, NOAA, 2725 Montlake Blvd E, Seattle WA 98112, USA
• ^d Ocean Acidification Program, Office of Oceanic and Atmospheric Research and Northwest Fisheries Science Center, National Marine Fisheries Service, NOAA, 2725 Montlake Blvd E, Seattle WA 98112, USA
• ^e CSIRO Oceans and Atmosphere, GPO Box 1538, Hobart, Tasmania 7001, Australia
• ^f Centre for Marine Socioecology, University of Tasmania, 20 Castray Esplanade, Hobart, Tasmania 7004, Australia
• ^g NOAA Pacific Marine Environmental Laboratory, 7600 Sand Point Way NE, Seattle WA 98115, USA
• ^h Joint Institute for the Study of the Atmosphere and Ocean, University of Washington, 3737 Brooklyn Ave NE, Seattle, WA 98105, USA

Access to full article can be found here: https://www.sciencedirect.com/science/article/pii/S0304380018301856

Coastal Researchers, Fishermen Worried About More Frequent Low Oxygen Zones

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.

The technical term is hypoxia, sometimes called “dead zones,” It’s an unwelcome variation on normal upwelling of cold, nutrient rich water from the deep ocean. When the dissolved oxygen drops too low, it drives away fish and can suffocate bottom dwellers such as crabs and sea worms who can’t scurry away fast enough.

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.

Originally published: http://nwnewsnetwork.org/

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.”

Matthew O. Berger, NewsDeeply, 2 October 2017. Article.

Originally published: https://news-oceanacidification-icc.org/

Canary in the kelp forest

The one-two punch of warming waters and ocean acidification is predisposing some marine animals to dissolving quickly under conditions already occurring off the Northern California coast, according to a study from the University of California, Davis.

In the study, published in the journal Proceedings of the Royal Society B: Biological Sciences, researchers at the UC Davis Bodega Marine Laboratory raised bryozoans, also known as “moss animals,” in seawater tanks and exposed them to various levels of water temperature, food and acidity.

The scientists found that when grown in warmer waters and then exposed to acidity, the bryozoans quickly began to dissolve. Large portions of their skeletons disappeared in as little as two months.

“We thought there would be some thinning or reduced mass,” said lead author Dan Swezey, a recent Ph.D. graduate in professor Eric Sanford’s lab at the UC Davis Bodega Marine Laboratory. “But whole features just dissolved practically before our eyes.”

SKELETONS KEY

Bryozoans are colonial animals, superficially similar to, but not related, to corals. They are abundant in California kelp forests and are calcareous, meaning they build their honeycomb-shaped skeletons from calcium carbonate.

The scientists found that when raised under warming conditions, bryozoans altered their chemical composition by building higher levels of magnesium into their skeletons, particularly if they were also eating less food. When exposed to acidic conditions already observed off coastal California, these changes predisposed the animals to dissolve.

The researchers consider bryozoans a canary in the coal mine for other marine animals that build calcareous skeletons containing magnesium. These include sea stars, sea urchins, calcifying algae and tube-building worms.

The authors do not know why the bryozoans added more magnesium to their skeletons under warmer temperatures. But they conclude that marine organisms with skeletons made of high-magnesium calcite may be especially susceptible to ocean acidification because this form of calcium carbonate dissolves more easily than others.

Bryozoans grow in connected colonies. During the experiments, the animals shut down parts of themselves when undergoing the stress of ocean acidification, redirecting their energy to new growth. This was somewhat like closing down units of a condominium complex while building new ones at the same time. But the moss animals could not outpace the dissolution.

“They were trying to grow but were dissolving at the same time,” Swezey said.

CALCIFIED ANIMALS INCREASINGLY VULNERABLE

The authors said the study underlines the increasing vulnerability of calcified animals to ocean acidification, which occurs as the ocean absorbs more atmospheric carbon emitted through the burning of fossil fuels.

During the spring and summer months, deep ocean water rich in carbon dioxide periodically wells up along the California coast when surface waters are pushed offshore by strong winds. These upwelling events also push nutrients to the surface to help support kelp forests and productive fisheries. However, this deep water tends to be more acidic.

Climate modeling shows that the trends of warming ocean temperatures, stronger winds and increasingly strong upwelling events are expected to continue in the coming years as carbon dioxide concentrations in the atmosphere increase. This indicates that acidic conditions will likely become more common, rather than episodic.

MARINE LIFE FACES MANY CHANGES AT ONCE

“Marine life is increasingly faced with many changes at once,” said co-author Sanford, a professor in the UC Davis Department of Evolution and Ecology. “For bryozoans, their response to warmer temperature makes them unexpectedly vulnerable to ocean acidification. The question now is whether other marine species might respond in a similar way.”

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The study’s other co-authors include Jessica Bean, Aaron Ninokawa, Tessa Hill, and Brian Gaylord from UC Davis. Bean is also affiliated with UC Berkeley.

The study was supported by grants from the National Science Foundation and the University of California Multicampus Research Programs and Initiatives. Swezey was also supported by a NSF Graduate Research Fellowship.

Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.

Originally posted: https://www.eurekalert.org/pub_releases/2017-04/uoc–cit041717.php

Ocean acidification to hit West Coast Dungeness crab fishery, new assessment shows

The acidification of the ocean expected as seawater absorbs increasing amounts of carbon dioxide from the atmosphere will reverberate through the West Coast’s marine food web, but not necessarily in the ways you might expect, new research shows.

Dungeness crabs, for example, will likely suffer as their food sources decline. Dungeness crab fisheries valued at about $220 million annually may face a strong downturn over the next 50 years, according to the research published Jan. 12 in the journal Global Change Biology. But pteropods and copepods, tiny marine organisms with shells that are vulnerable to acidification, will likely experience only a slight overall decline because they are prolific enough to offset much of the impact, the study found.

Dungeness crab.jkirkhart35/Flickr

Marine mammals and seabirds are less likely to be affected by ocean acidification, the study found.

“What stands out is that some groups you’d expect to do poorly don’t necessarily do so badly – that’s probably the most important takeaway here,” saidKristin Marshall, lead author of the study who pursued the research as a postdoctoral researcher at the University of Washington and NOAA Fisheries’ Northwest Fisheries Science Center. “This is a testament in part to the system’s resilience to these projected impacts. That’s sort of the silver lining of what we found.”

While previous studies have examined the vulnerability of particular species to acidification in laboratories, this is among the first to model the effects across an entire ecosystem and estimate the impacts on commercial fisheries.

“The real challenge is to go from experiments on what happens to individual animals in the lab over a matter of weeks, to try to capture the effects on the whole population and understand how vulnerable it really is,” said Isaac Kaplan, a research scientist at NOAA Fisheries’ Northwest Fisheries Science Center in Seattle.

The research used sophisticated models of the California Current ecosystem off the Pacific Coast to assess the impacts of a projected 0.2 unit decline in the pH of seawater in the next 50 years, which equates to a 55 percent increase in acidity. The California Current is considered especially vulnerable to acidification because the upwelling of deep, nutrient-rich water low in pH already influences the West Coast through certain parts of the year.

The ocean absorbs about one-third of carbon dioxide released into the atmosphere from the burning of fossil fuels, which has led to a 0.1 unit drop in pH since the mid-1700s.

The research built on an earlier effort by NOAA scientists Shallin Busch and Paul McElhanythat quantified the sensitivity of various species to acidification, as originally reported in 393 separate papers. In a novel approach, Busch and McElhany weighed the evidence for each species based on its reported sensitivity in the laboratory, relevance to the California Current and agreement between studies.

This synthesis by Busch and McElhany identified 10 groups of species with highest vulnerability to acidification. Marshall and colleagues incorporated this into the ecosystem model to examine how acidification will play out in nature. The study particularly examined the effects on commercially important species including Dungeness crab; groundfish such as rockfish, sole and hake; and coastal pelagic fish such as sardines and anchovy over the period from 2013 to 2063.

The study modeled the potential risks of ocean acidification (under a future decrease in pH) on the West Coast marine food web and fisheries over 50 years, from 2013 to 2063. NOAA Fisheries

“This was basically a vulnerability assessment to sharpen our view of where the effects are likely to be the greatest and what we should be most concerned about in terms of how the system will respond,” said Tim Essington, a UW professor of aquatic and fishery sciences and a co-author of the research.

The study provides a foundation for further research into the most affected species, he said.

Although earlier studies have shown that Dungeness crab larvae is vulnerable to acidification, the assessment found that the species declined largely in response to declines in its prey – including bivalves such as clams and other bottom-dwelling invertebrate species.

Since Dungeness crab is one of the most valuable fisheries on the West Coast, its decline would have some of the most severe economic effects, according to the research. Groundfish such as petrale sole, Dover sole and deep-dwelling rockfish are also expected to decline due to acidification, according to the assessment. However, fisheries for those species are much less valuable so the economic impact would not be as large.

Coastal pelagic fish were only slightly affected.

“Dungeness crab is a bigger economic story than groundfish,” Kaplan said. “There are winners and losers, but the magnitude of the impact depends on how important the species is economically.”

The research was funded by the NOAA Ocean Acidification Program and the National Centers for Coastal Ocean Science. Marshall was supported by a National Research Council fellowship.

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For more information, contact Marshall at kmarsh2@uw.edu and Kaplan atisaac.kaplan@noaa.gov 206-302-2446.

This piece was adapted from a Northwest Fisheries Science Center news release.

Sea Snails on Acid

Twice a day the rocky Pacific coast traps seawater in pools as the tide rolls in and out. Compared to the ocean, the puddles are so small and innocuous that it seems nothing momentous could possibly be happening there, but there is. It turns out tiny black turban snails may be getting a buzz from the changing levels of acidity caused by ocean acidification. The scientists at Bodega Marine Lab looked closely at sea stars and snails to find out.

The underside of the purple sea star is covered in tiny delicate suction cups that make one wonder how it moves fast enough to be a voracious hunter, but it is. It’s the bully on the playground, a merciless predator. It can pry open mussel shells, turn its stomach inside out and wrap it around large prey, and digest its meal before even swallowing. It’s no wonder that when black turban snails sense the purple star’s arrival, they all flee to safety, crawling quickly up the side of a tide pool until the enemy leaves the water. Quickly for snails, that is.

Snails have always been good at running away from their primary predator – the purple sea star – until now. Brittany Jellison, a graduate student at University of California Davis, has found in a recent study that the snail’s dramatic response might be slowing down because of ocean acidification. Jellison modified tide pools to mimic ocean acidification conditions. Then she observed the snail’s response by measuring the path they took to safety. What she found when watching the snail was a trippy set of behaviors.

“Elevated carbon dioxide is a foreign substance in seawater, and snails are taking that foreign substance into their body, so yes, they in essence are on drugs,” said Brian Gaylord, a professor at UC Davis Bodega Marine Lab, where Jellison discovered that under ocean acidification conditions, snails didn’t immediately flee the pool to safety.

Ocean acidification occurs when the ocean absorbs excess carbon dioxide from the atmosphere.  While most scientists studying the phenomenon are trying to understand how it effects a single species in a lab, Jellison’s work explores how ocean acidification effects multiple species interactions.

“I think what’s really important here is that she is moving beyond thinking about an individual species, and instead thinking about how the direct effects on individuals scale up when they are in nature and interacting with other species. That is the important part of it,” said Kristy Kroeker, Assistant Professor at the Department of Ecology and Evolutionary Biology at University of California Santa Cruz.

Professor Philip Munday of James Cook University agrees. He studies how ocean acidification effects reef fish and their ability to adapt to a changing environment.

“Ecosystems are a whole combination of interactive species,” said Munday. “If we want to understand how ocean acidification is going to impact marine ecosystems we need to understand how it will impact with the really critical ecological interactions, such as predatory-prey interactions. That’s one of the really exciting things about Jellison’s work.”

Tide pools on the Pacific coast have natural fluctuations in acidity, and the black turban snail and other animals that live there have adapted to that. Jellison wondered if the snails would be tolerant to ocean acidification conditions as well, or if they would reach their tipping point, and no longer able to tolerate the changes.

To find out, Jellison made model tide pools in aquariums. So that the snails would feel most at home, she simulated the conditions of natural tide pools, with one exception. Jellison changed the levels of acidification in some of the pools to mimic the levels that are expected for rock pools under ocean acidification by the year 2100. Having some tide pools with normal conditions and some with future acidic conditions allowed her to compare the behavior of sober snails with snails on acid.

With the arena built, let the show begin. Clutching her camera, Jellison carefully lowered black turban snails into the tank. One by one the snails reacted to a chemical cue produced by the predator sea star. Jellison took photos every two minutes for a half hour, then analyzed them for the distance the snails traveled, where they moved, and most importantly, if they left the water and escaped to safety. In total, Jellison did two 5-day trials, created 32 aquariums, tested 32 snails, and took photos every two minutes for 28 minutes per snail.

Under normal conditions, the snails will run away and exit the water, a flight response that keeps them safe. Jellison found that in water with higher acidity the snails started to run away, but instead of moving to dry ground, they seemed to get confused, haphazardly meandering around the pool.

Ocean acidification’s ability to change the interactions between predators and prey can have far reaching consequences. Jellison and her team aren’t yet sure exactly why the snails act confused. They think it’s related to changes in the brain as the animal tries to maintain balanced brain chemistry, which is something they would like to understand further.

“I really love research and I especially love working with marine animals,” said Jellison, “but when I think about what my work is saying about the future it can be a little bit hard to take in. Most of the things we are finding is that the world is going to look very different form what we see today.”

In the meantime, Jellison continues this research out in the field, in a creative study that has her waking up at all hours to hike to the tide pools and observe snails – all to understand the cascading effects of ocean acidification on the ecosystem. “I have a lot of hope that we will move forward as a society and try to come up with solutions and actually make changes. It is having hope that is important,” said Jellison.

Ocean acidification may cross national boundaries, and reach all corners of the earth, but a glimpse into a puddle of seawater reveals an elaborate community, a tiny snail, and a big message.

Read the original post: https://blogs.scientificamerican.com/guest-blog/sea-snails-on-acid/

Ocean Acidification Affects Predator-Prey Response Acidic Waters Dull Snails’ Ability to Escape from Predatory Sea Stars

Black turban snails escape predation by sea stars by crawling out of tide pools. Experiments at UC Davis’ Bodega Marine Laboratory show that the snails lose this escape response as waters become more acidic, a consequence of climate change. Photo: Brittany Jellison

Ocean Acidification Affects Predator-Prey Response | UC Davis

Ocean souring on climate change

“This upwelling is both a blessing and a curse,” Chan said. “The upwelling injects nutrients that make our ocean so productive. That’s why Steinbeck wrote ‘Cannery Row.’ We live in a very special ocean. But the curse is that this upwelling creates low oxygen and low pH. So we’re much closer to any tipping points that could push us past a threshold.”

Although the causes and effects of ocean acidification and low oxygen are global, the panel found hopeful news about the potential to deal with it locally.

Seagrass beds and kelp forests are more productive than tropical forests, capturing more carbon than other systems on the planet. By restoring marine vegetation, scientists hope to raise pH and oxygen levels in key areas.

Curbing marine pollution can also improve ocean chemistry, scientists said. Runoff from farms and lawns, such as nitrogen and phosphorus, feed algal blooms that dump carbon and deplete oxygen from local waters. Cutting back on those pollutants can “put off a potential evil hour when carbon dioxide are so high” that they cause irreparable damage to marine life, Dickson said.

Efforts to battle ocean acidification and low oxygen on the West Coast will be test cases for dealing with the problem elsewhere, scientists said

“The West Coast will be a harbinger for the types of ocean acidification impacts that will be widely felt across coastal North America in the coming decades,” the report states.

Despite the gloomy news, Chan said he’s hopeful that a solution is at hand, noting that bills pending in the California Legislature — Assembly Bill 2139 and Senate Bill 1363 — would study ocean acidity and promote eelgrass restoration.

“I’m leaving with an optimistic note, which I tend not to as a scientist, but I think the people who make decisions get it, and are ready to do something,” he said.

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