The oceans can’t take any more: researchers fear a fundamental change in the oceans – even if greenhouse emissions are successfully reduced

A press release from the Alfred Wegener Institute: Our oceans need an immediate and substantial reduction of anthropogenic greenhouse gas emissions. If that doesn’t happen, we could see far-reaching and largely irreversible impacts on marine ecosystems, which would especially be felt in developing countries. That’s the conclusion of a new review study published today in the journal Science. In the study, the research team from the Ocean 2015 initiative assesses the latest findings on the risks that climate change poses for our oceans, and demonstrates how fundamentally marine ecosystems are likely to change if human beings continue to produce just as much greenhouse gases as before.

Since the pre-industrial era, the carbon dioxide concentration in the atmosphere has risen from 278 to 400 ppm (parts per million) – a 40 percent increase that has produced massive changes in the oceans. “To date, the oceans have essentially been the planet’s refrigerator and carbon dioxide storage locker. For instance, since the 1970s they’ve absorbed roughly 93 percent of the additional heat produced by the greenhouse effect, greatly helping to slow the warming of our planet,” explains Prof Hans-Otto Pörtner, co-author of the new Ocean 2015 study and a researcher at the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research.

But the oceans have also paid a high price: as far down as 700 metres the water temperatures have risen, which has forced some species to migrate up to 400 kilometres closer to the Earth’s poles within the past decade. Given the increasing acidification in many regions, it’s becoming more and more difficult for corals and bivalves to form their calcium carbonate skeletons. In Greenland and the western Arctic, the ice is melting at an alarming rate, contributing to rising sea levels. As a result of these factors, the biological, physical and chemical processes at work in marine ecosystems are changing – which will have far-reaching consequences for marine life and humans alike.

In their new study, the research team from the Ocean 2015 initiative employs two emissions scenarios (Scenario 1: Achieving the 2-degree goal / Scenario 2: Business as usual) to compile the main findings of the IPCC’s 5th Assessment Report and the latest professional literature, and to assess those findings with regard to the risks for our oceans. “If we can successfully limit the rise in air temperature to two degrees Celsius through the year 2100, the risks, especially for warm-water corals and bivalves in low to middle latitudes, will become critical. However, the remaining risks will remain fairly moderate,” explains lead author Jean-Pierre Gattuso. But a rapid and comprehensive reduction of carbon dioxide emissions would be needed in order to achieve this ideal option, he adds....

An Australian pelican watches a beach sunrise, shot by bigwavephoto big wave photo, Wikimedia Commons, under the Creative Commons Attribution-Share Alike 4.0 International License 

New challenges for ocean acidification research

A press release from GEOMAR, the Helmholtz Centre for Ocean Research-Kiel: To continue its striking development, ocean acidification research needs to bridge between its diverging branches towards an integrated assessment. This is the conclusion drawn by Prof. Ulf Riebesell from GEOMAR Helmholtz Centre for Ocean Research Kiel and Dr. Jean-Pierre Gattuso from the French Centre National de la Recherche Scientifique (CNRS) and Université Pierre et Marie Curie. In a commentary in the journal “Nature Climate Change”, the two internationally renowned experts reflect on the lessons learned from ocean acidification research and highlight future challenges.

Over the past decade, ocean acidification has received growing recognition not only in the scientific area. Decision-makers, stakeholders, and the general public are becoming increasingly aware of “the other carbon dioxide problem”. It is time to reflect on the successes and deficiencies of ocean acidification research and to take a look forward at the challenges the fastest growing field of marine science is facing. In the January issue of the journal “Nature Climate Change” Ulf Riebesell, professor for Biological Oceanography at GEOMAR Helmholtz Centre for Ocean Research Kiel, and Jean-Pierre Gattuso from the French Centre National de la Recherche Scientifique (CNRS) urge the international scientific community to undertake a concerted interdisciplinary effort. According to the two experts, future ocean acidification research will have to deal with three major challenges: It needs to expand from single to multiple drivers, from single species to communities and ecosystems, and from evaluating acclimation to understanding adaptation. “The growing knowledge in each of the diverging research branches needs to be assimilated into an integrated assessment”, Prof. Riebesell points out.

For the scientific community, it is obvious that ocean acidification does not occur in isolation. Rising temperatures, loss of oxygen, eutrophication, pollution and other drivers happen simultaneously and interact to influence the development of marine organisms and communities. “The effects can be additive, synergistic or antagonistic and it is generally not possible to extrapolate from single- to multiple-driver responses”, Prof. Riebesell explains. “But with an increasing number of parameters, experiments become increasingly challenging in terms of time, space and costs. Also, it becomes ever more difficult to compare and verify results of similar studies.”

There is now an impressive body of scientific literature on how individual species react to ocean acidification as a single driver. Many calcifying organisms such as corals, mussels or snails will find it more and more difficult to build their shells and skeletons. The extra energy needed for calcification will be lacking for other biological processes, such as growth or reproduction. "But an open question is to what extent results from short-term, single-driver laboratory experiments can be extrapolated to the real world“, Dr. Gattuso states.

Field experiment on the effects of ocean acidification with the KOSMOS mesocosms developed in Kiel. Photo: Maike Nicolai, GEOMAR

Increasingly acidic oceans threaten world's mussel populations

The Guardian (UK) via Press Association: The world’s mussel population could be under threat as climate change causes the oceans to become more acidic, scientists have warned. Mussel shells become more brittle when they are formed in more acidic water, Glasgow University has reported in the Royal Society journal Interface.

Carbon dioxide in the atmosphere causes the oceans to become more acidic and reduces the concentration of the minerals mussels need to generate their shells, according to scientists. However, they also found that mussels may have an in-built biological defence mechanism which boosts shell development when water temperatures rise by 2C.

Dr Fitzer said: “What we’ve found in the lab is that increased levels of acidification in their habitats have a negative impact on mussels’ ability to create their shells. “We worked with colleagues in our School of Engineering to examine the toughness of the shells of the mussels in the more acidic water against those in control conditions.

“What we found was that the calcite outer shells of the mussels past a certain threshold of acidity was stiffer and harder, making it more brittle and prone to fracture under pressure, and the aragonite inner shell became softer.

The shellfish industry is worth more than £250m a year to the UK economy with a large part accounted for by mussels and oysters, the UK Department for Environment, Food and Rural Affairs reported in 2012....

A mussel shell from the Netherlands, shot by Emma Versteegh, Wikimedia Commons, under the Creative Commons Attribution-Share Alike 2.5 Generic license

Acidifying oceans alarm hundreds of scientists

Environment News Service: Climate change is causing the world’s oceans to acidify at rates not seen for the last 55 million years, and the only way to moderate this danger is to reduce human emissions of carbon dioxide, conclude 540 scientists from 37 countries in a new report.

Their conclusion is the outcome of the Third Symposium on the Ocean in a High CO2 World that took place in Monterey, California in September 2012. The findings of these experts were presented in a report to the Conference on Climate Change that took place in Warsaw from November 11 to 22.

Reflecting the latest research on the subject, the report was prepared by UNESCO’s Intergovernmental Oceanographic Commission, the Scientific Committee on Ocean Research  and the International Geosphere-Biosphere Programme.

The scientists expect “substantial changes” in marine ecosystems, marine biodiversity and coral reefs that have the potential to affect food security. They warn that seashell fisheries could lose some US$130 billion annually, if current CO2 emissions remain unchanged.

It emerges that all the oceans, which together absorb close to one quarter of the CO2 emissions generated by human activity, have experienced an overall 26 percent rise in acidity since the dawn of the industrial age.

Twenty-four million tonnes of CO2 are absorbed by the oceans every day and, if current emission rates are maintained, the level of the ocean acidity worldwide will rise by 170 percent before 2100, compared to the pre-industrial age....

A cliff vista shot by psyberartist, Wikimedia Commons via Flickr, under the Creative Commons Attribution 2.0 Generic license

Ocean acidification set to spiral out of control

Jan Piotrowski in SciDev.net: The continued release of greenhouse gases into the air is set to bring about huge changes to land ecosystems as they are forced to adapt to rising temperatures. But the marine world — which is just as integral to human existence yet receives little attention during climate negotiations — will endure a similarly tumultuous time as emissions rise, scientists say.

“Changing oceans will cause massive destruction of coral reefs, which, with their rich biodiversity, are the jungles of the sea,” says Luis Valdes, the head of ocean science at UNESCO’s Intergovernmental Oceanographic Commission (IOC-UNESCO), and co-author of a forthcoming report into ocean acidification.

This is expected to hit marine species used for food and have knock-on effects on coastal communities, especially in developing countries. Business-as-usual carbon dioxide emissions will lead to the acidity levels of oceans rising by 170 per cent by 2100 compared with pre-industrial levels, according to a report to be launched next week at COP 19 (Conference of the UN Framework Convention on Climate Change).

The report will be published jointly by the International Geosphere-Biosphere Programme, the IOC-UNESCO and the Scientific Committee on Oceanic Research. As carbon dioxide levels in the atmosphere rise, some of this extra carbon is absorbed by the oceans and converted into acidic compounds...

A bubble filters the sun, shot by Joe Burch, Wikimedia Commons, under the Creative Commons Attribution-Share Alike 3.0 Unported license

No safe havens in increasingly acid oceans

Stephen Leahy in IPS: Oil, gas and coal are contaminating the world’s oceans from top to bottom, threatening the lives of more than 800 million people, a new study warns Tuesday. “It took a year to analyse and synthesise all of the studies on the impacts of climate change on ocean species,” Camilo Mora, an ecologist at University of Hawai‘i in Honolulu and lead author, told IPS.

"We are seeing greater changes, happening faster, and the effects are more imminent than previously anticipated." -- Alex Rogers of the University of Oxford Mora is also lead author of ground-breaking climate study published in Nature last week.

“It was very sad to see all the responses were negative. We were hoping there might be some safe havens,” he said. The study found that carbon emissions from burning fossil fuels are overheating the oceans, turning them acidic and reducing the amount of oxygen in seawater. This is happening too fast for most marine species to adapt and ocean ecosystems around the world will collapse.

By 2100, no corner of the oceans that cover 70 percent of the Earth’s surface will be untouched. “The impacts of climate change will be felt from the ocean surface to the seafloor. It is truly scary to consider how vast these impacts will be,” said Andrew Sweetman of the International Research Institute of Stavanger, Norway, co-author of th PLOS Biology study published Oct. 15.

This ambitious study examined all the available research on how current and future carbon emissions are fundamentally altering the oceans. It then looked at how this will impact fish, corals, marine animals, plants and other organisms. Finally the 29 authors from 10 countries analysed how this will affect the 1.4 to 2.0 billion people who live near the oceans or depend on them for their food and income.

...“We are making a big mess of the oceans. Climate change is having a major impact illustrating the need for urgent action to reduce emissions,” said Mora....

A humpback whale breaching, shot by Gillfoto, Wikimedia Commons, under the Creative Commons Attribution-Share Alike 3.0 Unported license

Stressed krill first sign of damage

Andrew Darby in the Sydney Morning Herald: Turns out it's the little things we need to worry about in climate change. When they're in trouble, a great polar ecosystem may be, too.

The oceans are now absorbing so much carbon dioxide they are acidifying at an unprecedented rate, according to the International Program on the State of the Ocean. Geological records show the current acidification is unparalleled in at least the past 300 million years, IPSO's latest State of the Ocean report says. ''We are entering an unknown territory of marine ecosystem change, and exposing organisms to intolerable evolutionary pressure,'' it says.

The smallest of these creatures in the remote Antarctic marine ecosystem are said to be showing some of the earliest signs of acidification damage. And work by Australian scientists shows greater problems lie in store for the creatures at the centre of the Antarctic food web - krill.

Environment Minister Greg Hunt pointed to warnings of increasing ocean acidification as the most important new advice from the Intergovernmental Panel on Climate Change's latest report. ''In the debate around climate change, research on acidification of the oceans is a particular personal concern,'' Mr Hunt said. ''This has been reinforced by the work of Australian scientists, particularly in the Antarctic.

''The Southern Ocean is specially vulnerable to increased acidity because of the cold water and the type of marine life. If there are changes in these environments, then there is a flow-on impact across the entire marine system.''...

Antarctic krill, shot by Uwe Kils, Wikimedia Commons, under the Creative Commons Attribution-Share Alike 3.0 Unported license

Insight into marine life's ability to adapt to climate change

EurekAlert via the University of Plymouth: A study into marine life around an underwater volcanic vent in the Mediterranean, might hold the key to understanding how some species will be able to survive in increasingly acidic sea water should anthropogenic climate change continue.

Researchers have discovered that some species of polychaete worms are able to modify their metabolic rates to better cope with and thrive in waters high in carbon dioxide (CO2), which is otherwise poisonous to other, often closely-related species. The study sheds new light on the robustness of some marine species and the relative resilience of marine biodiversity should atmospheric CO2 continue to cause ocean acidification.

A team of scientists led by Plymouth University, and including colleagues from the Naples Zoological Station in Ischia; the Marine Ecology Laboratory ENEA in La Spezia, Italy; the University of Texas Galveston; and the University of Hull, conducted a three-year research project into the potential mechanisms that species of worm polychaetes use to live around the underwater CO2 vent of Ischia in Southern Italy.

...They monitored the responses of the worms and found that one of the species that had been living inside the CO2 vent was physiologically and genetically adapted to the acidic conditions, whilst another was able to survive inside the vent by adjusting its metabolism.

...The results revealed that species normally found inside the CO2 vent were better able to regulate their metabolic rate when exposed to high CO2 conditions, whilst species only found outside the CO2 vent were clearly impaired by acidic waters. In fact, their metabolism either greatly decreased, indicating reduced energy production, or greatly increased, indicating a surge in the basic cost of living, in both cases making life inside the vent unsustainable.

Dr Maria-Cristina Gambi, of the Naples Zoological Station in Ischia, explained: "Despite some species showing the ability to metabolically adapt and adjust to the extreme conditions that are found inside the CO2 vents, others appear unable to physiologically cope with such conditions. In this sense, our findings could help to explain mass extinctions of the past, and potential extinctions in the future, as well as shed light on the resilience of some species to on-going ocean acidification."...

Sully Vent in the Main Endeavour Vent Field of the northeastern Pacific Ocean. Shot by NOAA, public domain

Rising levels of acids in seas may endanger marine life

Fiona Harvey in the Guardian (UK): Rapidly rising carbon dioxide levels in the atmosphere are causing a potential catastrophe in our oceans as they become more acidic, scientists have warned. Hans Poertner, professor of marine biology at the Alfred Wegener Institute in Germany, and co-author of a new study of the phenomenon, told the Guardian: "The current rate of change is likely to be more than 10 times faster than it has been in any of the evolutionary crises in the earth's history."

Seawater is naturally slightly alkaline, but as oceans absorb CO2 from the air, their pH level falls gradually. Under the rapid escalation of greenhouse gas emissions, ocean acidification is gathering pace and many forms of marine life – especially species that build calcium-based shells – are under threat.

Poertner said that if emissions continue to rise at "business as usual" rates, this would be potentially catastrophic for some species. Acidification is just one of a broader range of the problems facing the oceans and the combination of different effects is increasing the threat. Poertner said: "We are already seeing warm water coral reefs on a downslide due to a combination of various stressors, including [rising] temperature. Ocean acidification is still early in the process [but] it will exacerbate these effects as it develops and we will see more calcifying species suffering."

However, the process of acidification takes decades and the worst effects on some species could still be avoided if emissions are urgently reduced. "The ocean is changing already, mostly due to temperature – acidification will exacerbate those effects," Poertner said.

Evidence from prehistoric ocean life provides a comparison. "The [effects observed] among invertebrates resembles those seen during the Permian Triassic extinctions 250m years ago, when carbon dioxide was also involved. The carbon dioxide range at which we see this sensitivity [to acidification] kicking in are the ones expected for the later part of this century and beyond."...

Crustacean wagon in Morgan's Slough. I believe it's...man-made!  Shot by Mette Batterton, under the Creative Commons Attribution-Share Alike 3.0 Unported license

Why we need to put the fish back into fisheries

Space Daily via SPX: Overfishing has reduced fish populations and biodiversity across much of the world's oceans. In response, fisheries are increasingly reliant on a handful of highly valuable shellfish. However, new research by the University of York shows this approach to be extremely risky.

The research, published in the journal Fish and Fisheries, shows that traditional fisheries targeting large predators such as cod and haddock, have declined over the past hundred years. In their place, catches of shellfish such as prawns, scallops and lobsters have rocketed as they begin to thrive in unnaturally predator-low environments often degraded by the passage of trawls and dredges.

In many places, including the UK, shellfish are now the most valuable marine resource. The research by the Environment

Department at York suggests that although a shellfish-dominated ecosystem appears beneficial from an economic perspective, it is highly risky. Like simplified agricultural systems, these shellfisheries are unstable in the long-term and at great risk of collapse from disease, species invasions and climate change.

Warming and acidification of our oceans due to greenhouse gas emissions is expected to affect shellfish worst. Ocean acidification, in particular, will limit the ability of scallops and other shellfish to form proper shells, and lead to widespread mortality....

Shellfish on a beach, shot by Titus Tscharntke, Wikimedia Commons, public domain

Arctic Ocean 'acidifying rapidly'

Roger Harrabin in the BBC: The Arctic seas are being made rapidly more acidic by carbon-dioxide emissions, according to a new report. Scientists from the Arctic Monitoring and Assessment Programme (AMAP) monitored widespread changes in ocean chemistry in the region.

They say even if CO2 emissions stopped now, it would take tens of thousands of years for Arctic Ocean chemistry to revert to pre-industrial levels. Many creatures, including commercially valuable fish, could be affected. They forecast major changes in the marine ecosystem, but say there is huge uncertainty over what those changes will be.

It is well known that CO2 warms the planet, but less well-known that it also makes the alkaline seas more acidic when it is absorbed from the air. Absorption is particularly fast in cold water so the Arctic is especially susceptible, and the recent decreases in summer sea ice have exposed more sea surface to atmospheric CO2.

The Arctic's vulnerability is exacerbated by increasing flows of freshwater from rivers and melting land ice, as freshwater is less effective at chemically neutralising the acidifying effects of CO2. The researchers say the Nordic Seas are acidifying over a wide range of depths - most quickly in surface waters and more slowly in deep waters....

The Arctic Ocean, off Tromso, Norway, shot by Vinay Deep, Wikimedia Commons via Flickr, under the Creative Commons Attribution 2.0 Generic licens

New study reveals how sensitive US east coast regions may be to ocean acidification

Science Daily: A continental-scale chemical survey in the waters of the eastern U.S. and Gulf of Mexico is helping researchers determine how distinct bodies of water will resist changes in acidity. The study, which measures varying levels of carbon dioxide (CO2) and other forms of carbon in the ocean, was conducted by scientists from 11 institutions across the U.S. and was published in the journal Limnology and Oceanography.

"Before now, we haven't had a very clear picture of acidification status on the east coast of the U.S.," says Zhaohui 'Aleck' Wang, the study's lead author and a chemical oceanographer at Woods Hole Oceanographic Institution (WHOI). "It's important that we start to understand it, because increase in ocean acidity could deeply affect marine life along the coast and has important implications for people who rely on aquaculture and fisheries both commercially and recreationally."

Coastal ocean acidification, Wang says, can occur when excess carbon dioxide is absorbed by, flushed into or generated in coastal waters, setting off a chain of chemical reactions that lowers the water's pH, making it more acidic. The process disproportionately affects species like oysters, snails, pteropods, and coral, since those organisms cannot effectively form shells in a more acidic environment.

...Since the waters of the northeast U.S. are already susceptible to rising acidity, Wang says this raises big questions about how species of marine life -- many of which are important to the commercial fishing and shellfish industry there -- will fare in the future. "For example, how are oysters going to do? What about other shellfish? If the food chain changes, how are fish going to be impacted?" Wang asks. "There's a whole range of ecological and sociological questions." There is a great need for need for more robust coastal ocean chemistry monitoring and coastal ocean acidification studies, he adds. A better understanding of the changing chemistry will help fisheries regulators to better manage the stocks....

By collecting and analyzing water samples, Wang and his colleagues charted the coastal ocean’s capacity to buffer itself from increase input of CO2or resist a change in pH (shown as a ratio of total alkalinity, TA, to dissolved inorganic carbon, DIC). The dark blue color indicates a low capacity; red indicates a higher capacity. The waters in the Gulf of Mexico are more resistant to change; the waters off New Hampshire and Massachusetts are less resistant. In the figure, the contour lines labeled with numbers represent the calcium carbonate saturation state of aragonite, a mineral form of calcium carbonate. The higher numbers mean shell-building organisms have more carbonate with which produce their shells than areas with lower numbers, where less carbonate is available for shell building. Shells will dissolve in waters with a saturation state value below 1, but organisms will feel the effect of low saturation state before it reaches 1. (Credit: Courtesy Wang, et al., 2013)

Ocean acidity rivals climate change as environmental threat

The Smithsonian puts a confusing title to this article, since acidification is a consequence of greenhouse gas emissions: .... [W]ithin the last 50 years, human industry has caused the world’s oceans to experience a sharp increase in acidity that rivals levels seen when ancient carbon cycles triggered mass extinctions, which took out more than 90 percent of the oceans’ species and more than 75 percent of terrestrial species.

Rising ocean acidity is now considered to be just as much of a formidable threat to the health of Earth’s environment as the atmospheric climate changes brought on by pumping out greenhouse gases. Scientists are now trying to understand what that means for the future survival of marine and terrestrial organisms.

In June, ScienceNOW reported that out of the 35 billion metric tons of carbon dioxide released annually through fossil fuel use, one-third of those emissions diffuse into the surface layer of the ocean. The effects those emissions will have on the biosphere is sobering, as rising ocean acidity will completely upset the balance of marine life in the world’s oceans and will subsequently affect humans and animals who benefit from the oceans’ food resources.

The damage to marine life is due in large part to the fact that higher acidity dissolves naturally-occurring calcium carbonate that many marine species–including plankton, sea urchins, shellfish and coral–use to construct their shells and external skeletons. Studies conducted off Arctic regions have shown that the combination of melting sea ice, atmospheric carbon dioxide and subsequently hotter, CO2-saturated surface waters has led to the undersaturation of calcium carbonate in ocean waters. The reduction in the amount of calcium carbonate in the ocean spells out disaster for the organisms that rely on those nutrients to build their protective shells and body structures....

Some clown fish off the coast of Spain, Esv, public domain

Global ocean acidification monitoring network to launch at Rio summit

Juliet Eilperin in the Washington Post:   Efforts to deal with increasing acidification of the oceans will get a signal of support Sunday with a U.S. announcement that it will provide $1 million over the next three years to launch a global monitoring network.

The creation of the International Coordinating Office for Ocean Acidification, which will be housed within the International Atomic Energy Agency’s Environment Laboratories in Monaco, marks the first worldwide effort to track how increasing carbon emissions are making the world’s oceans more acidic.

Officials from the United States, which, along with Australia and New Zealand, will establish the office, will make the announcement Sunday afternoon at the Rio+20 Earth Summit, a once-in-a-decade meeting that is convening in Rio de Janeiro this week. Also known as the U.N. Conference on Sustainable Development, the gathering aims to assess the state of the planet and take steps to solve its most critical problems.

Still, Sunday’s announcement also highlights some of the fiscal constraints global policymakers face when it comes to the environment. Scientists have estimated a robust global ocean acidification monitoring effort will cost $50 million....

Hokusai's "Ocean Waves"

Ocean acidification linked to larval oyster failure

Oregon State University: Researchers at Oregon State University have definitively linked an increase in ocean acidification to the collapse of oyster seed production at a commercial oyster hatchery in Oregon, where larval growth had declined to a level considered by the owners to be “non-economically viable.”

A study by the researchers found that elevated seawater carbon dioxide (CO2) levels, resulting in more corrosive ocean water, inhibited the larval oysters from developing their shells and growing at a pace that would make commercial production cost-effective. As atmospheric CO2 levels continue to rise, this may serve as the proverbial canary in the coal mine for other ocean acidification impacts on shellfish, the scientists say. Results of the research have just been published in the journal, Limnology and Oceanography.

“This is one of the first times that we have been able to show how ocean acidification affects oyster larval development at a critical life stage,” said Burke Hales, an OSU chemical oceanographer and co-author on the study. “The predicted rise of atmospheric CO2 in the next two to three decades may push oyster larval growth past the break-even point in terms of production.”

....“The early growth stage for oysters is particularly sensitive to the carbonate chemistry of the water,” said George Waldbusser, a benthic ecologist in OSU’s College of Earth, Ocean, and Atmospheric Sciences. “As the water becomes more acidified, it affects the formation of calcium carbonate, the mineral of which the shell material consists. As the CO2 goes up, the mineral stability goes down, ultimately leading to reduced growth or mortality.”...

Pacific oysters, shot by David Monniaux and modified by Peter Gugerell, Wikimedia Commons, under the Creative Commons Attribution 2.5 Generic license

Can cold-water corals adapt to climate change?

Geomar, the Helmholtz Center for Ocean Research Kiel (Germany): Are cold-water corals able to withstand ocean acidification? A long-term experiment carried out at the German Helmholtz Centre for Ocean Research Kiel (GEOMAR) showed, that the species Lophelia pertusa continues growth when exposed to ocean acidification. This unexpected finding is now published by GEOMAR scientists in “Global Change Biology”. In a new series of experiments, they will analyse how the corals react to combined changes in carbon dioxide concentration, temperature and food availability as projected to occur during the next decades to centuries.

By absorbing about a third of man-made carbon dioxide (CO2), the ocean decelerates global warming. However, when dissolved in seawater, CO2 reacts to produce carbonic acid, causing seawater pH to decrease. It also diminishes the concentration of carbonate ions, thereby putting organisms forming their shells and skeletons from calcium carbonate at risk. Apart from plankton, algae, mussels and snails, stony corals are among those particularly endangered: Their skeletons consist of aragonite, the most soluble form of calcium carbonate.

“Model calculations indicate that if CO2-emissions continue at current rates, more than 70 percent of cold-water coral reefs known today will be exposed to conditions corrosive for calcium carbonate by the end of this century. It seemed obvious, therefore, that these corals will be among the first to suffer from the effects of ocean acidification”, explains Ulf Riebesell, Professor of Biological Oceanography at GEOMAR. “But our results do not support this”, adds the Kiel marine biologist Dr. Armin Form. “For the first time ever, we showed that the globally widespread species Lophelia pertusa keeps growing even in corrosive waters if given the time to adjust to the new conditions.” Armin Form and Ulf Riebesell now presented their results in the renowned journal Global Change Biology....

Sampling Lophelia pertusa with JAGO. Photos: JAGO-Team, GEOMAR, from the GEOMAR website

Unprecedented, man-made trends in oceans acidity

The Hawaii Reporter: Nearly one-third of CO2 emissions due to human activities enters the world’s oceans. By reacting with seawater, CO2 increases the water’s acidity, which may significantly reduce the calcification rate of such marine organisms as corals and mollusks, resulting in the potential loss of ecosystems. The extent to which human activities have raised the surface level of acidity, however, has been difficult to detect on regional scales because it varies naturally from one season and one year to the next, and between regions, and direct observations go back only 30 years.

By combining computer modeling with observations, an international team of scientists concluded that anthropogenic CO2 emissions, resulting from the influence of human beings, over the last 100 to 200 years have already raised ocean acidity far beyond the range of natural variations. The study is published in the January 22, 2012 online issue of Nature Climate Change.

The team of climate modelers, marine conservationists, ocean chemists, biologists and ecologists, led by Tobias Friedrich and Axel Timmermann at the International Pacific Research Center at the University of Hawai‘i at Mānoa, came to their conclusions by using Earth system models that simulate climate and ocean conditions 21,000 years back in time, to the Last Glacial Maximum, and forward in time to the end of the 21st century. In their models, they studied changes in the saturation level of aragonite (a form of calcium carbonate) typically used to measure ocean acidification.

As acidity of seawater rises, the saturation level of aragonite drops. Their models captured the current observed seasonal and annual variations in this quantity in several key coral reef regions.

Today’s levels of aragonite saturation in these locations have already dropped five times below the pre-industrial range of natural variability. For example, if the yearly cycle in aragonite saturation varied between 4.7 and 4.8, it varies now between 4.2 and 4.3, which – based on another recent study – may translate into a decrease in overall calcification rates of corals and other aragonite shell-forming organisms by 15%. Given the continued human use of fossil fuels, the saturation levels will drop further, potentially reducing calcification rates of some marine organisms by more than 40% of their pre-industrial values within the next 90 years.

“Any significant drop below the minimum level of aragonite to which the organisms have been exposed to for thousands of years and have successfully adapted will very likely stress them and their associated ecosystems,” said lead author Friedrich...

An illustration of some coral from the Austrian National Library, Kommentar von Otto Mazal (S. 47 und 52) in: Pedanius Dioscorides – Der Wiener Dioskurides, Codex medicus Graecus 1 der Österreichischen Nationalbibliothek, Graz: Akademische Druck- und Verlagsanstalt 1998 (Band 2). ISBN 3-201-01725-6

Major study of ocean acidification helps scientists evaluate effects of atmospheric carbon dioxide on marine life

UC Santa Barbara Office of Public Affairs: Might a penguin's next meal be affected by the exhaust from your tailpipe? The answer may be yes, when you add your exhaust fumes to the total amount of carbon dioxide lofted into the atmosphere by humans since the industrial revolution. One-third of that carbon dioxide is absorbed by the world's oceans, making them more acidic and affecting marine life.

A UC Santa Barbara marine scientist and a team of 18 other researchers have reported results of the broadest worldwide study of ocean acidification to date. Acidification is known to be a direct result of the increasing amount of greenhouse gas emissions. The scientists used sensors developed at Scripps Institution of Oceanography at UC San Diego to measure the acidity of 15 ocean locations, including seawater in the Antarctic, and in temperate and tropical waters.

As oceans become more acidic, with a lower pH, marine organisms are stressed and entire ecosystems are affected, according to the scientists. Gretchen E. Hofmann, an eco-physiologist and professor in UCSB's Department of Ecology, Evolution & Marine Biology, is lead author of the recent article in PLoS ONE that describes the research.

..."The emerging pH data from sensors allows us to design lab experiments that have a present-day environmental context," said Hofmann. "The experiments will allow us to see how organisms are adapted now, and how they might respond to climate change in the future."

....The researchers found that, in some places such as Antarctica and the Line Islands of the South Pacific, the range of pH variance is much more limited than in areas of the California coast that are subject to large vertical movements of water, known as upwellings. In some of the study areas, the researchers found that the decrease in seawater pH being caused by greenhouse gas emissions is still within the bounds of natural pH fluctuation. Other areas already experience daily acidity levels that scientists had expected would only be reached at the end of this century.....

UCSB graduate student Emily Rivest positions a SeaFET pH sensor in a coral reef off the island of Moorea, in French Polynesia. TThe reefs surrounding the island of Moorea are home to UCSB's Coral Reef Long-Term Ecological Research site (MCR LTER). Credit: Anderson Mayfield