Ocean Acidification

The longest ocean time series of dissolved carbon dioxide in the Pacific — part of the “Keeling Curve of the ocean” — is revealed.

For the first time, scientists at UC San Diego’s Scripps Institution of Oceanography have published nearly four decades’ worth of dissolved carbon dioxide measurements from waters off Southern California. The measurements reveal a slight but consistent trend of ocean acidification, a process characterized by a decrease in the ocean’s pH over time due to its absorption of carbon dioxide (CO₂) from the atmosphere.

Since the early 1980s, samples of ocean carbonate chemistry have been collected by the California Cooperative Oceanic Fisheries Investigations (CalCOFI) program, which was established in 1949 to investigate the collapse of the sardine population off California. In a new study, Scripps Oceanography researchers present 37 years of measurements from CalCOFI Line 90 Station 90 (station 90.90), a measuring site located 450 kilometers (280 miles) off the coast of San Diego. The team’s findings were published on Nov. 3 in Communications Earth & Environment, a journal affiliated with Nature.

The measurements from station 90.90 establish the oldest time series of direct inorganic carbon observations in the Pacific Ocean. While measurements at the station carry on to the present day, the study details quarterly measurements collected from 1984 to 2021, with a gap from 2002 to 2008 due to a lack of funding. Notably, the data show that the seawater at the study site is getting more acidic, with a measured decrease in pH of 0.0015 per year.

Published by Back to Blue, a new report Ocean Acidification: Time for Action calls on international government action to step up in a bid to prevent the worst case scenario from unfolding. It also criticises the majority of countries for ‘ocean blindness’, and failing to factor this issue into climate change adaptation and mitigation plans. 

Currently, just 12 countries have in the world have ocean acidification action plans, yet if the problem is allowed to persist and become worse, some $400billion could be wiped off the global economy. 

As oceans are allowed to become more acidic, a direct result of absorbing increasing amounts of carbon dioxide, the effect on marine life is unforgiving, including the creation of so-called ‘dead zones’, and the destruction of finely balanced ecosystems. In turn, this is a major threat to the survival of coastal communities, many of which have developed due to the abundant riches found under water, not least fisheries, meaning the livelihoods of vast swathes of people now hangs in the balance.

According to data, policy advice and research institution the OECD, globally some three billion people rely on oceans for their income. In the U.S., for example, almost half the national GDP is tied to counties that are coastal adjacent, and more than three-million jobs, or one-in-45, are directly dependent on resources within the sea or Great Lakes. 

…

You can read the full report here.

When scientists estimated that more than 10 billion snow crab had disappeared from the Eastern Bering Sea between 2018 and 2021, industry stakeholders and fisheries scientists had several ideas about where they’d gone.

Some thought bycatch, disease, cannibalism, or crab fishing, while others believed it could be predation from other sea animals like Pacific cod.

But now, scientists say they’ve distinguished the most likely cause for the disappearance. The culprit is a marine heatwave between 2018 and 2019, according to a new study authored by a group of scientists with the National Oceanic and Atmospheric Administration.

…

More carbon dioxide in the atmosphere means warmer temperatures, Litzow said, which is bad news for the cold-loving snow crab. And more greenhouse gasses also mean more acidic oceans, which can also be dangerous for some crab.

“Carbon dioxide that we release through fossil fuels is also taken up by the oceans and has the effect of reducing the pH of the ocean — it makes it more acidic,” Litzow explained. “Because crab use calcium carbonate in their exoskeleton, they’re vulnerable to that acidification because calcium carbonate dissolves more and more easily as pH goes down.”

The good news — at least for snow crab — is they’re not as sensitive to ocean acidification as other species.

…

Scientists at the J. Craig Venter Institute (JCVI) and Scripps Institution of Oceanography at the University of California San Diego have for the first time shown that increased acidification of ocean water in an upwelling region reduces the availability of iron for phytoplankton, thereby threatening to reduce overall phytoplankton productivity. Given that phytoplankton sit at the base of the oceanic food web, acidification is a concern to all life in these upwelling regions. Upwelling regions are among the most productive due to the concentration of nutrients brought from deep water, driven by coastal winds. Results for this study are published in the journal Nature Communications.

While discussing the impact of this research, lead author Robert Lampe, a graduate student at Scripps Oceanography and JCVI stated, “This study provides critical insight into how key organisms in this ecosystem may respond to future conditions. Our current projections for how organisms and biological processes will respond to climate change are still quite uncertain and this brings us a step closer towards understanding change in the ecosystem.”

Aboard the R/V Atlantis, a research vessel owned by the U.S. Navy and operated by Woods Hole Oceanographic Institution (WHOI), JCVI and Scripps scientists spent 32 days in the California Current, a cold-water Pacific Ocean Current that runs southward along the western coast of North America. The team began their experiments—to better understand how acidification affects marine microbial life—near Big Sur, California and moved progressively farther from shore, performing four experiments in total.

…

Fifty years ago, NOAA created a new environmental research laboratory in Seattle with an initial focus on water quality in Puget Sound, and environmental studies of the Gulf of Alaska and Bering Sea. Since then, the Pacific Marine Environmental Laboratory has evolved into one of the world’s leading ocean research institutes, specializing in observing ocean conditions from tsunamis to changes in climate and ocean chemistry with the aid of innovative instrumentation and measurement strategies often developed by the lab.

To recognize PMEL’s half-century of accomplishments, the journal Oceanography has published a special issue with 29 diverse articles which highlight the laboratory’s scientific work over the last five decades. The issue provides new perspectives on global and regional implications of ocean acidification and its biological impacts, the influence of El Nino-Southern Oscillation on global weather patterns, and the important role marine aerosols play in regulating climate.  

“PMEL researchers and their collaborators not only have fundamentally reshaped the scientific understanding of so many aspects of our ocean, their research and explorations have sparked  our imagination and fascination with the deep and all that we might learn about our planet,” said NOAA Administrator and former President of The Oceanography Society Rick Spinrad, Ph.D. “Year after year, PMEL scientists continue to inspire the next generation of scientists and researchers, while providing the nation with the priceless knowledge gained by their investigations.”

…

The acidification of the oceans caused by human activity is already altering the production of marine plankton shells in the Mediterranean Sea. This is the worrying conclusion of a study led by the Institute of Environmental Science and Technology of the Universitat Autònoma de Barcelona (ICTA-UAB), which alerts of the impact the decrease in pH of the surface ocean has on the production of calcium carbonate by marine plankton, with negative consequences for marine ecosystems.

Credit: Photo: ICTA-UAB

The acidification of the oceans caused by human activity is already altering the production of marine plankton shells in the Mediterranean Sea. This is the worrying conclusion of a study led by the Institute of Environmental Science and Technology of the Universitat Autònoma de Barcelona (ICTA-UAB), which alerts of the impact the decrease in pH of the surface ocean has on the production of calcium carbonate by marine plankton, with negative consequences for marine ecosystems.

Anthropogenic carbon dioxide (CO₂) emissions have increased alarmingly in recent decades. Since the Industrial Revolution, about 25% of anthropogenic CO₂ has entered the ocean, changing water chemistry and lowering pH, a phenomenon known as ocean acidification.

The acidification of the Earth’s oceans is expected to triple by 2100, and could lead to major impacts on biodiversity across U.S. coastlines.

With climbing atmospheric CO2, huge amounts of this gas are absorbed by the oceans, dissolving to form carbonic acid, making the waters more and more acidic. This affects a huge number of marine animals and plants alike, but its impact on fleshy seaweeds around the coast may have knock-on effects across the food web, and make our beaches much less pleasant, according to a new study published in the journal Current Biology.

“We found evidence that OA (ocean acidification) could make seaweeds more vulnerable to physical damage, which could come from storms or from grazing animals,” study author and marine sciences researcher at the University of Gothenburg in Sweden, Alexandra Kinnby, told Newsweek.

“If this vulnerability means that the amount of seaweed decreases significantly it could have effects on the entire coast. Seaweeds form the base of the near-shore food web, they provide food and shelter to many small organisms which are in turn food for larger species,” she said.

Date: September 25, 2023

Source: Cell Press

Summary: Ocean acidification will likely almost triple by the end of the century — a drastic environmental change that could impact important marine species like fleshy seaweeds, algae that grow vertically and promote biodiversity in more than a third of the world’s coastline. To get a better idea of how seaweeds might fare in a rapidly acidifying ocean, a team of marine scientists subjected a common fleshy seaweed species to the acidification levels expected by the end of the century. They report that increased acidification impacted the seaweed’s chemical balance, made both its structure and its tissues weaker, and reduced its overall chances of survival.

Ocean acidification will likely almost triple by the end of the century — a drastic environmental change that could impact important marine species like fleshy seaweeds, algae that grow vertically and promote biodiversity in more than a third of the world’s coastline. To get a better idea of how seaweeds might fare in a rapidly acidifying ocean, a team of Swedish marine scientists subjected a common fleshy seaweed species to the acidification levels expected by the end of the century. In a study publishing on September 24 in the journal Current Biology, they report that increased acidification impacted the seaweed’s chemical balance, made both its structure and its tissues weaker, and reduced its overall chances of survival.

“Climate change is resulting in unprecedented changes in terrestrial and aquatic ecosystems through the emission of greenhouse gases, including carbon dioxide,” write the authors, who are based at the University of Gothenburg and the KTH Royal Institute of Technology. “Almost a third of that CO₂ is taken up by the ocean, which has profound effects on seaweeds.”

A new objective examination of almost a quarter-of-a-century of ocean acidification research shows that, despite challenges, experts in the field can have confidence in their research.

The University of Adelaide’s Professor Sean Connell from the Ecology and Evolutionary Biology unit led the study.

“In our field, the marine science community was galvanised by the demonstration of how ocean acidification impairs shell-building life, which has profound implications for life on the planet,” he said.

“It is an inescapable fact that ocean acidification does impose harmful effects on shell-building life.”

This field is transformational and one of the most studied single topics in marine science in recent times.

Like all scientific research, findings were subjected to intense scrutiny including how to reproduce early results. Early in the history of ocean acidification research, controversy erupted over a set of failures to reproduce its effects on key behaviours of tropical fish.

Most people consider climate change to consist only of the warming of the atmosphere, the consequences of which primarily affect land regions. However, this is a human-centered view and does not go far enough.

This view overlooks the fact that the oceans are also strongly affected by climate change. Not only do they absorb a large part of the extra heat that the increased concentration of greenhouse gases generate in the atmosphere, they also absorb about one-third of manmade CO₂ emissions from the atmosphere. This CO₂ uptake causes the oceans to acidify—with significant consequences for marine life.

“Despite these profound changes, many people are not aware of what is happening to our oceans,” says Nicolas Gruber, Professor of Environmental Physics at ETH Zurich. The marine researcher and his team want to change that.

But how can people understand such an abstract concept for a complex process in an unfamiliar habitat?

A study of the country’s two largest estuaries reveals that inshore coastal waters are not necessarily experiencing what scientists say is a worrisome global trend of increasingly acidic oceans.

The recently published paper is the latest in a small collection of studies highlighting the complexities of coastal zones onshore.

In this case, researchers looked at trends from data collected more than 20 years within the Neuse River Estuary-Pamlico Sound waters and Chesapeake Bay and found that things like nutrient pollution and algal blooms play a role in how carbon dioxide is dissolved in inland coastal waters.

Research Assistant Professor Nathan Hall with the University of North Carolina Chapel Hill Institute of Marine Sciences in Morehead City and co-author of the study explained that eutrophication is effectively causing, in some cases, estuarine waters to have lower acidification than that of the ocean.

Oceanic responses to climate and human interactions have been studied for decades. In recent years the effects of increasing ocean acidity have been featured, with stark images of coral reefs being decimated by bleaching.

Acidification results from ocean-atmosphere interactions, whereby carbon dioxide from the atmosphere is drawn down, reacting with water molecules to form carbonic acid. This then further breaks down into hydrogen ions and bicarbonate ions, with the former causing a reduction in pH.

Corals are not the only marine organisms to be made up of calcium carbonate and therefore susceptible to ocean acidification however. Single-celled organisms known as foraminifera produce chambered shells of calcium carbonate, and they are an important part of marine food chains, being primary and secondary consumers. Most tend to be benthic, where they live in or at the seafloor, but a smaller proportion are planktonic, living within the water column.

New research, published in Geoscience Frontiers, has focused on the impact of acidification on benthic foraminifera living on the continental shelf of the West Pacific Ocean. Researchers at the Institute of Oceanology in the Chinese Academy of Sciences conducted experiments for eight months on foraminifera cultures taken from four sites in the Yellow Sea, involving 4,626 specimens attributed to 39 species. They tested foraminifera response to marine conditions when progressively more carbon dioxide (400ppm, 800ppm, 1200ppm and 1600ppm) was fed into the system. This reflects modeling scenarios reported by the Intergovernmental Panel on Climate Change (IPCC) where worse-case scenario simulations are based upon carbon dioxide concentrations of 1,600 ppm and above.

…

[You can read the original research article published on the OA-ICC News Stream here.]

Marine biologists are increasingly seeking methods to mitigate anthropogenic climate interference by implementing strategies for ocean carbon dioxide removal (CDR). Ocean alkalinity enhancement parameter is an abiotic approach aimed at carbon dioxide removal. Attempts to increase the carbon dioxide uptake capacity of the ocean can be established by dispersing pulverized mineral or dissolved alkali into the ocean surface.

Nevertheless, the impact of this action remains largely unexplored. In a new report now published in Science Advances, James A. Gately and a research team in ecology and development biology at the University of California, Santa Barbara, U.S., studied the impact of limestone-inspired alkalinity on the bioecology of two phytoplankton functional groups—the coccolithophore (single-celled) Emiliania huxleyi a producer of calcium carbonate, responsible for large-scale calcium carbonate production, and the diatom specimen Chaetoceros sp., a silica producer in modern oceans.

Emiliania huxleyi, a single-celled marine phytoplankton is illustrated on the cover page of the Science Advances issue, and the two taxa (coccolithophore and diatom) together showed a neutral response to limestone-inspired alkalization relative to their growth rate and elemental ratios. The team additionally noted abiotic precipitation, which removed nutrients and alkalinity from the solution to offer an understanding of biogeochemical and physiological responses to ocean alkalinity enhancement in order to provide evidence of its greater impact and its capacity to influence marine ecosystems.

…

European Maritime Day 2023 took place in Brest, France, on 24 and 25 May 2023. OSPAR, as an affiliate member of the International Alliance to Combat Ocean Acidification (OA Alliance), co-convened the side event “Exploring Marine Management and Policy Response to Ocean Acidification” to advance the integration of climate change information across key European marine management frameworks, together with the International Alliance to Combat Ocean Acidification (OA Alliance), and the NE Atlantic Hub of the Global Ocean Acidification Observing Network (GOA-ON).

The meeting brought together policy and decision-makers across Europe to discuss:

1. Ocean acidification trends, biological impacts and threats to keystone fisheries and aquaculture within the Arctic, North Atlantic and Mediterranean;
2. OSPAR’s assessment on ocean acidification published as part of OSPAR’s Quality Status Report 2023, as well as national response strategies;
3. EU and national ocean and marine policy frameworks.

Jos Schilder, co-convenor of the OSPAR Intersessional Correspondence Group on Ocean Acidification (ICG-OA), presented the work that OSPAR is undertaking to tackle ocean acidification. He introduced the OSPAR Ocean Acidification Assessment that was recently published as part of OSPAR’s Quality Status Report 2023, and the approach and methods used to prepare it. As the key findings of this assessment show clearly that ocean acidification is continuing in the OSPAR Region and is putting marine life under pressure, recommendations for next steps in research and policy were highlighted.

Washington, DC – During Capitol Hill Oceans Week (CHOW), U.S. Senators Lisa Murkowski (R-AK) and Sheldon Whitehouse (D-RI), co-chairs of the U.S. Senate Oceans Caucus, reintroduced the Coastal Communities Ocean Acidification Act, legislation that will ensure coordination and collaboration between federal, state, local and tribal entities on ocean acidification research and monitoring.

“Ocean acidification continues to increase as the climate changes, causing harm to ocean resources that many of our coastal communities, Alaska Native cultures, and economy relies on. If we don’t have policies in place to address and coordinate on ocean acidification, we are at risk of far-reaching impacts on shellfish, fish populations, and ocean ecosystems. The time to act is now so we can protect Alaskan subsistence communities and America’s seafood economy.” said Senator Murkowski. “I’m proud to reintroduce my Coastal Communities Ocean Acidification Act during Capitol Hill Oceans Week, sending a strong message to advocates in D.C. and across the country that we are committed to understanding the impacts and extent of climate change-caused ocean acidification, and what more we can do to ensure healthy oceans for future generations.”

“Ocean acidification caused by carbon pollution is a major threat to Rhode Island’s aquaculture industry and to the overall health of our oceans,” said Senator Whitehouse.  “Our bipartisan legislation will build on local efforts to combat acidification across the country and ensure coastal industries can continue grow.”

This legislation would direct NOAA to collaborate with and support state, local, and tribal entities that are conducting or have completed ocean acidification vulnerability assessments or research planning to build upon the existing activities. The bill strengthens partnerships between NOAA and a wide range of stakeholders involved in ocean acidification research, such as indigenous groups, coastal communities, state and local resource managers, fishery management councils and commissions, and the U.S. Integrated Ocean Observing System (IOOS).

…

Pteropod shells could be more resilient to, but still face risks from increasingly acidic waters.

Aboard a Coast Guard research boat off the middle of Vancouver Island, a tiny sea snail is lightly pinned under a microscope with the bristles of a fine-tipped paintbrush to not puncture its three-millimetre shell.

Between the swaying of the Salish Sea, Matt Miller carefully scratches the pteropod’s shell with a small dissecting needle before placing the snail in a solution mirroring the increasingly acidic water from where the creature was pulled.

The University of Victoria PhD student was looking to see if the damaged shell areas dissolved while other spots held strong. The results formed the basis of his new study that casts doubt on whether the creatures dubbed as sea butterflies should serve a key role in understanding the impacts of acidifying oceans.

The burning of fossil fuels and other actions adds carbon dioxide into the atmosphere before the gasses meet with global waters. “Because we’ve put more CO2 into the atmosphere, it means that more is dissolving into the ocean and when that happens it creates a reaction with seawater and it creates an acid called carbonic acid,” Miller said. It’s how humans have reduced the PH of the oceans, increasing their acidity by 30 per cent in just 150 years.

Summary: Researchers are proposing a novel pathway through which coastal ecosystem restoration can permanently capture carbon dioxide from the atmosphere. Seagrass and mangroves — known as blue carbon ecosystems — naturally capture carbon through photosynthesis, which converts carbon dioxide into living tissue.

One of the primary drivers of climate change is excess greenhouse gases like carbon dioxide in the atmosphere. Mitigating climate change in the coming century will require both decarbonization — electrifying the power grid or reducing fossil fuel-guzzling transportation — and removing already existing carbon dioxide from the atmosphere, a process called carbon dioxide removal.

Researchers at the Georgia Institute of Technology and Yale University are proposing a novel pathway through which coastal ecosystem restoration can permanently capture carbon dioxide from the atmosphere. Seagrass and mangroves — known as blue carbon ecosystems — naturally capture carbon through photosynthesis, which converts carbon dioxide into living tissue.

“Mangroves and seagrasses extract carbon dioxide from the atmosphere all day long and turn it into biomass,” said Chris Reinhard, an associate professor in the School of Earth and Atmospheric Sciences (EAS). “Some of this biomass can get buried in sediments, and if it stays there, then you’ve basically just removed carbon dioxide from the atmosphere.”

Restoring these ecosystems could potentially benefit local flora and fauna and help to energize coastal economies. But Reinhard and colleagues now suggest that restoring them could also remove additional carbon through a novel pathway while combating increasing acidity in the ocean.

In May, they presented their research in “Ocean Alkalinity Enhancement Through Restoration of Blue Carbon Ecosystems” in Nature Sustainability.

Alkaline hydrothermal systems are considered ideal environments for the origin of life because they can provide ideal ion gradient conditions for the formation of early life on Earth.

However, alkaline hydrothermal vents have only been found in the Lost City hydrothermal field in the Atlantic Ocean. Additionally, accurately obtaining the in-situ pH of high-temperature hydrothermal vent fluids is a challenge.

Recently, a research team led by Prof. Zhang Xin from the Institute of Oceanology of the Chinese Academy of Sciences (IOCAS) and their collaborators from the University of Science and Technology Beijing constructed an in-situ pH measurement method for high-temperature hydrothermal fluids based on the self-developed Raman insertion Probe (RiP) system.

They applied it to the measurement of arc-back arc (ABA) hydrothermal systems and revealed that the in-situ pH of high-temperature fluids in the sediment-host hydrothermal systems is alkaline. The study was published in Geophysical Research Letters on May 10.

The researchers used a deep-sea extreme environment simulation platform to conduct quantitative analysis of the H₂S-HS^– ion equilibrium system. They established Raman quantitative analysis models for H₂S and HS^– under high-temperature and high-pressure conditions, as well as an in-situ pH calibration model for hydrothermal fluids.

The world’s oceans absorb approximately a quarter of all carbon dioxide (CO₂) emissions. During absorption, CO₂ reacts with seawater and oceanic pH levels fall. This is known as ocean acidification and results in lower carbon ion concentrations. Certain ocean inhabitants use carbon ion to build and sustain their shells. Pteropods, which are important components of the marine ecosystem, are among them.

Certain aspects about pteropods, including life cycles and population dynamics, are not well-studied. This is partly due to their size—some sea butterfly species measure less than a millimeter—and poor long-term survival in captivity. Now, a team of marine scientists has examined life cycles, abundance, and seasonal variability of shelled sea butterflies in the north-east Scotia Sea, a region undergoing some of the fastest climate change in the Southern Ocean.

“Decline in Antarctic Ocean pteropod populations could have cascading ramifications to the food web and carbon cycle,” said Dr. Clara Manno, a researcher at the British Antarctic Survey and corresponding author of the study published in Frontiers in Marine Science. “Knowledge about the life cycle of this keystone organism may improve prediction of ocean acidification impacts on the Antarctic ecosystem.”

…

A new study by researchers at the University of Toronto finds that climate change is causing a commercially significant marine crab to lose its sense of smell, which could partially explain why their populations are thinning. 

The research was done on Dungeness crabs and found that ocean acidification causes them to physically sniff less, impacts their ability to detect food odours and even decreases activity in the sensory nerves responsible for smell.  

“This is the first study to look at the physiological effects of ocean acidification on the sense of smell in crabs,” says Cosima Porteus, an assistant professor in the department of biological sciences at U of T Scarborough and co-author of the study along with post-doctoral researcher Andrea Durant.      

The Earth’s oceans are becoming more acidic because they are absorbing increasing amounts of carbon dioxide in the atmosphere. Such ocean acidification is a direct consequence of burning fossil fuels and carbon pollution – and several studies have shown it’s having an impact on the behaviour of marine wildlife.

…