Archive for February, 2010

Can corals adapt to climate change and ocean acidification?

New research from American Samoa suggests that at least some coral can withstand warmer waters

For plants, animals and marine life whose environment changes, their options are stark and simple: Move, adapt or die.

But when the marine life in question is a coral reef cemented to the ocean floor and the threat is climate change, the outlook appears grimmer, said scientists presenting new findings here at the annual meeting of the American Association for the Advancement of Science.

Even small temperature rises of 1 to 2 degrees Celsius in the ocean can make corals more prone to bleaching, a kind of sudden death that occurs when corals expel the algae that normally live inside them, providing them with food and their bright coloration.

Scientists are also worried that, as carbon dioxide emissions rise, the ocean will absorb greater amounts of the greenhouse gas, shifting the chemistry of seawater. As the ocean becomes more acidic, it will be harder for corals to grow. Eventually, ocean water could become corrosive, dissolving reefs faster than corals can grow.

The question now is whether reef-building corals have the capacity to adapt to those changes.

“Can reefs disappear? That’s the question,” said Joanie Kleypas of the National Center for Atmospheric Research. “We don’t have a lot of information on this.”
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Coral reefs in danger of being destroyed

Rising acidity of the oceans is threat to marine ecosystems, study warns

All of the tropical coral reefs in the world will be disintegrating by the end of the century because of the rising acidity of the oceans caused by a build-up of man-made carbon dioxide in the atmosphere, a study has found.

Coral reefs start to disintegrate when the acidity of the oceans rises beyond a certain threshold, and this point is likely to be reached before 2100, said Jacob Silverman of the Carnegie Institution of Science in Washington.

Carbon dioxide in the air dissolves in the sea to form carbonic acid, which interferes with the ability of coral organisms to make their calcium carbonate shells which form coral reefs, Dr Silversman said. But once the shells stop forming, the reef quickly crumbles.

A mathematical model was used to study how 9,000 coral reefs from around the world would respond to rising levels of carbon dioxide and increasing ocean acidity, Dr Silverman told the American Association for the Advancement of Science in San Diego.

“A global map produced on the basis of these calculations shows that all coral reefs are expected to stop their growth and start to disintegrate when atmosphere CO2 reaches 560 parts per million – double its pre-industrial level – which is expected by the end of the 21st-century,” he told the meeting.
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CIOERT workshop on ocean acidification instrumentation and research needs

SRI International, Marine Technology Division, St. Petersburg FL
March 8-11, 2010


Title: New Instrumentation for Assessment of OA in Coral Ecosystems, and Modeling of Coral Calcification

Much of the effort to date to develop instruments to study the process and progression of ocean acidification (OA) has been aimed towards high precision and sensitivity instruments designed to measure small changes in SW chemistry in low variability oceanic waters (e.g. MAP-CO2, MICA, SAMI, SEAS, several mass specs, etc). These efforts have been accomplished with only minor coordination by a number of investigators at academic, R&D and NOAA institutions, and with substantial funding by NSF, NOAA and other federal agencies. In spite of such effort, much remains to be done to produce instruments that are reliable and robust enough for prolonged deployments. Coral reef ecosystems are one of the most vulnerable to OA but also the most complex to understand in terms of biotic/seawater interactions. Large biomass of organisms on/within coral reefs respire (adding to localized OA), photosynthesize (potentially counteracting OA), and calcify at various rates in various sub-habitats creating a complex patchwork of interactions between metabolism and bulk ocean water chemistry that the calcifying organisms live within and have to deal with on a daily basis. As a result of this biotic metabolism, coral reef seawater chemistry is highly variable over short time and spatial scales, and thus the instruments needed to study effects of OA on coral reef systems may have different specifications that those needed for oceanic studies. For both ecosystems, an integrated, autonomous instrument package is needed that measures at least two of the seawater carbonate parameters, and preferably three of them. The 3 day workshop will be held to critically review the instrumentation needs and specifications of various types of OA research especially for coral reefs, strengths and weaknesses of existing technologies, on-going developments, and funding needs which would allow integration into an instrument suite applicable to mid to long term deployment on coral reefs.
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Interview: Drop in the ocean

Peter Liss talks to Carl Saxton about the acidity of the sea, climate change and architecture.

Peter Liss is a professor at the University of East Anglia, Norwich, UK. His research encompasses many aspects of environmental chemistry, with a particular interest in the biogeochemical interactions between the oceans and the atmosphere.

What projects are you currently working on?

One topic that I have been working on for several years is how the oceans affect the atmosphere in terms of releasing trace gases made by marine planktonic organisms. For example, dimethylsulfide, made by plankton in the oceans, is volatile, and is oxidised in the atmosphere to produce sulphur dioxide and sulphate. In the natural system this sulphur dioxide is the source of acidity in the atmosphere and lowers the pH of rain. We have added to that acidity, particularly in the northern hemisphere, by burning fossil fuels, which put man-made sulphur dioxide into the atmosphere.
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International group of scientists collaborate to communicate about ocean acidification

Climate change is a well-known problem resulting from the burning of fossil fuels and the subsequent release of carbon dioxide (CO2) into the atmosphere. But a separate, lesser-known problem resulting from increased CO2 emissions is that the world’s oceans are becoming more acidic — raising concerns about the ability of certain organisms to survive in that altered environment and about the overall health of the oceans.

The problem is so pressing that an international group of scientists has banded together to help educate the public about “ocean acidification,” the scientific details of which are intricate and sometimes counterintuitive. Twenty-seven scientists from five countries worked together to produce and distribute a document to provide accessible and accurate answers to the most commonly asked questions about this growing problem.

“People need to understand that ocean acidification is happening right now. The acidity of the ocean has increased by 26 percent from pre-industrial times to today,” says Woods Hole Oceanographic Institution (WHOI) Senior Scientist Scott Doney, chair of the U.S. government-funded Ocean Carbon and Biogeochemistry (OCB) program, one of the driving forces behind the production of this document. “And if we continue on the present trajectory of fossil-fuel use and rising atmospheric CO2, the acidity could increase by 100 – 150 percent above pre-industrial levels. That could have significant impacts on ocean ecosystems around the planet.”

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Living in the now: Physiological mechanisms to tolerate a rapidly changing environment

Rising atmospheric carbon dioxide has resulted in scientific projections of changes in global temperatures, climate in general, and surface seawater chemistry. Although the consequences to ecosystems and communities of metazoans are only beginning to be revealed, a key to forecasting expected changes in animal communities is an understanding of species’ vulnerability to a changing environment. For example, environmental stressors may affect a particular species by driving that organism outside a tolerance window, by altering the costs of metabolic processes under the new conditions, or by changing patterns of development and reproduction. Implicit in all these examples is the foundational understanding of physiological mechanisms and how a particular environmental driver (e.g., temperature and ocean acidification) will be transduced through the animal to alter tolerances and performance. In this review, we highlight examples of mechanisms, focusing on those underlying physiological plasticity, that operate in contemporary organisms as a means to consider physiological responses that are available to organisms in the future.
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Confronting ocean acidification: options for management and policy

Friday, February 19, 2010: 3:30 PM-5:00 PM
Room 17A (San Diego Convention Center)

This symposium moves beyond scientific findings to highlight current measures and recommend additional actions to advance the management of ocean resources in the face of ocean acidification. A major challenge facing both the scientific and policy communities is how to mitigate and adapt to the impacts of increased atmospheric carbon dioxide. Among the potential effects of increased carbon dioxide emissions is its uptake by the oceans and the resultant decrease in seawater pH, a process known as ocean acidification. Scientists are only beginning to investigate this process; however, the potential effects of ocean acidification point to many environmental and socioeconomic consequences. These impacts, along with other effects of greenhouse gas emissions and climate change, are already influencing decisions by federal and state agencies regarding fisheries management, ecosystem restoration, coral reef protection, protected species management, and other living marine resource management.
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Podcast: Confronting ocean acidification

Earth’s oceans are becoming warmer and more acidic. What will the impacts be on marine life? And what should we, as humans, be most worried about? Science reporter Erik Stokstad gets some answers from ocean policy expert Edward Miles of the University of Washington, Seattle, a panelist at a session on the topic here at the annual meeting of the American Association for the Advancement of Science (which publishes ScienceNOW). Listen to their conversation here (mp3)—and learn why ocean acidification is known as the “evil twin.”
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Coral reefs being destroyed by climate change

Lost paradise worlds beneath the Earth’s oceans including those around the Britain are being “systemically destroyed” by climate change and over fishing before they can even be properly explored, claim scientists.

The amazingly colourful undersea oases of life, some more than a mile down, have only just been discovered and are thought to harbour countless unknown species of fish and plant-life.

But these cold water coral reefs – often growing on deep sea mountains – are falling victim to the double whammy of ocean acidification and deep sea trawling.

Those around the British Isles and Ireland have already been extensively damaged by scraping of sea nets and over-fishing of breeding grounds.

Now carbon dioxide absorption into the sea is increasing acidification and threatening to wear away the calcium which is the very building block of the reefs.

Dr Jason Hall-Spencer, marine biologists at the University of Plymouth, said the “weird and wonderful new discoveries” could disappear forever – before we even learn of their existence.
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Acidified landscape around ocean vents foretells grim future for coral reefs

Underwater vents allow scientists to assess the acidic effect of carbon dioxide on ocean life

Huge vents covering the sea-floor – among the strangest and most spectacular sights in nature – pour carbon dioxide and other gases into the deep waters of the oceans.

Last week, as researchers reported that they had now discovered more than 50,000 underwater volcanic springs, they also revealed a new use for them – as laboratories for measuring the impact of ocean acidification on marine life.

The seas are slowly being made more acidic by the increasing amounts of carbon dioxide from factories and cars being pumped into the atmosphere and then dissolved in the sea. The likely impact of this acidification worries scientists, because they have found that predicting the exact course of future damage is a tricky process.

That is where the undersea vents come in, says Dr Jason Hall-Spencer of the University of Plymouth. “Seawater around these vents becomes much more acidic than normal sea­water because of the carbon dioxide that is being bubbled into it,” he told a meeting of the American Association for the Advancement of Science in San Diego, California, last week. “Indeed, it reaches a level that we believe will be matched by the acidity of oceans in three or four decades. That is why they are so important.”
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Ocean acidification in the IPCC AR5 WG II

OUP book