What is the Big Deal About Ocean Acidification?

If you have been paying attention to environmental news lately you may have read or heard a little bit about this thing called ocean acidification. But what is ocean acidification and why is it such a big deal?

What is ocean acidification?

Ocean acidification, as the name suggests, is an increase in acidity of the world’s oceans which can be shown by a decrease in pH. This increase in acidity parallels an increase in CO2 in the earth’s atmosphere. This parallel increase occurs because CO2 stays balanced between the ocean and the atmosphere, so if the CO2 increases in the atmosphere, the ocean absorbs more CO2 to stay in equilibrium.

In the ocean, CO2 is also getting used up through a reaction with water and carbonate (a molecule that occurs naturally in the ocean) that creates bicarbonate and carbonic acid, both of which are acidic and decrease the pH of the ocean. Overall, this reaction causes an increase in acidity, a decrease in carbonate, and a decrease in CO2 in the ocean, which pulls more CO2 out of the atmosphere to maintain the CO2 balance. Find out more here.

What can you do to help? Get informed! Learn more about ocean acidification. Tell your friends! Tell your U.S. Senators or Representative that you are worried about the impacts of ocean acidification and that they should be too!

Read full article on marineconservationblog.blogspot.fr

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Unprecedented, man-made trends in ocean’s acidity

Via Scoop.itOcean News

Recent carbon dioxide emissions have pushed the level of seawater acidity far above the range of the natural variability that existed for thousands of years, affecting the calcification rates of shell-forming organism.
Via www.eurekalert.org

The Acid Truth About our Oceans: Experts Urge Action to Limit Ocean Acidification

World Oceans map image

Indian, Atlantic, Pacific, Artic, and Southern Ocean

IUCN Media Statement, 29 November 2011 – Ocean acidification can no longer remain on the periphery of the international debates on climate change and the environment and should be addressed by the UN Framework Convention on Climate Change and other global environmental conventions, urge IUCN and the International Ocean Acidification Reference User Group (RUG) at the climate change summit in Durban.

In the run up to the United Nations Conference on Sustainable Development, which will take place in Rio de Janeiro in June next year (Rio+20), world experts from RUG call for decision makers to urgently address the critical issue of ocean acidification.

“The increasing amounts of carbon dioxide that we emit into the atmosphere every day are changing our oceans, steadily increasing their acidity, and dramatically affecting marine life,” says Professor Dan Laffoley Marine Vice Chair of IUCN’s World Commission on Protected Areas and Chair of RUG.

“This may also have severe impacts on human life in the future. Only by reducing our CO2 emissions and enhancing the protection of oceans to strengthen their ability to recover, can we effectively address this issue. Policy makers in Durban, and in Rio in June next year, need to recognize this and take appropriate actions.”

Reducing greenhouse gas emissions into the atmosphere, particularly CO2, which is the main driver of climate change and the main cause of ocean acidification, is one of the goals of the UN Framework Convention on Climate Change. But the latest RUG publication calls for a broader strategy to reduce ocean acidification, alongside those tackling other threats to the marine environment such as overfishing and pollution.

According to the experts, although both climate change and ocean acidification are caused by excessive amounts of CO2 emissions, and so should be tackled together, not all approaches used to address the former will be effective in the fight against the latter.

“For example, ‘geoengineering’ solutions, such as reflecting solar radiation, which are often suggested to deal with climate change, will not address the progressive acidification of the ocean,” says Dr John Baxter of the Scottish Natural Heritage and Deputy Chair of the RUG.

“Both climate change and acidification need to be taken into account when designing solutions to these challenges.”

Each year, the ocean absorbs approximately 25% of all the CO2 we emit. Its acidity has increased by 30% since the beginning of the Industrial Revolution and acidification will continue at an unprecedented rate in the coming decades. This can have a negative impact on marine organisms, especially the ‘calcifying’ ones such as shellfish, molluscs, coral reefs and various types of zooplankton and phytoplankton. Increasing ocean acidity requires them to use more energy to build their shells, which has potentially severe ecological consequences. If the current acidification rate continues, it could lead to extinctions of some species and impact others that feed on them.

“Through its ability to absorb large amounts of CO2, the ocean plays a crucial role in moderating the rate and severity of climate change”, says Dr Carol Turley from the Plymouth Marine Laboratory and the Knowledge Exchange Coordinator for the UK Ocean Acidification Research Programme, one of the partners of the Reference User Group.

“But in many ways our ocean is also a victim of its own success, as this capacity jeopardizes its future health, its biodiversity and its ability to continue to provide us with food and sustainable economic development. Ocean acidification requires urgent and effective action now, before it’s too late. The obvious action is to reduce CO2 emissions to the atmosphere.”

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Acid oceans turn Finding Nemo fish deaf

Published on: June, 1 2011 – Richard Black, Environment Correspondant BBC NewsBBC News – Acid oceans turn ‘Finding Nemo’ fish deaf.

Clownfish, the spectacular tropical species featured in the movie Finding Nemo, appear to lose their hearing in water slightly more acidic than normal.

Clown Anemonefish Great Barrier Reef Australia imageAt levels of acidity that may be common by the end of the century, the fish did not respond to the sounds of predators.

The oceans are becoming more acidic because they absorb much of the CO2 that humanity puts into the atmosphere.

Scientists write in the journal Biology Letters that failing to move away from danger would hurt the fish’s survival.

“Avoiding coral reefs during the day is very typical behaviour of fish in open water,” said research leader Steve Simpson from the School of Biological Sciences at the UK’s Bristol University.

“They do this by monitoring the sounds of animals on the reef, most of which are predators to something just a centimetre in length.

“But sounds are also important for mate detection, pack hunting, foraging – so if any or all of those capacities are gone, you’d have a very lost fish,” he told BBC News.

Previous research has shown that fish also lose their capacity to scent danger in slightly more acidic seawater. The team raised baby clownfish in tanks containing water at different levels of acidity.

One resembled the seawater of today, with the atmosphere containing about 390 parts per million (ppm) of carbon dioxide.

The other tanks were set at levels that could be reached later this century – 600, 700 and 900 ppm.

The more CO2 there is in the atmosphere, the more the oceans absorb – and the more they absorb, the more acidic the water becomes.

In this experiment, the fish could decide whether to swim towards or away from an underwater loudspeaker replaying the sounds of predators recorded on a reef, with shrimps and fish that would take a small clownfish.

In water with today’s levels of CO2, the fish spent three-quarters of the time at the opposite end of the tube from the loudspeaker.

But at higher concentrations, they showed no preference. This suggests they could not hear, could not decipher or did not act on the warning signals.

“The reef has been described as ‘a wall of mouths’ waiting to receive the clownfish,” said Dr Simpson. “What we have done here is put today’s fish in tomorrow’s environment, and the effects are potentially devastating.”

If it takes several decades for the oceans to reach these more acidic levels, there is a chance, the team says, that fish could adapt.

Whether that can happen is one of the outstanding questions from this research. Another is whether other species are similarly affected.

A third question is why the fish are affected by these slight changes in acidity.

There appears to be no physical damage to their ears; the team suggests there could be some effect on nerves, or maybe they are stressed by the higher acidity and do not behave as they otherwise would.

Further experiments are in train that may answer those questions.

Concern about ocean acidification has arisen considerably more recently than alarm over global warming; but already there is ample evidence that it could bring significant changes to ocean life.

The organisms most directly affected appear to be corals and those that make shells, such as snails.

Just this weekend, another team of researchers published findings from a “natural laboratory” in the seas off Papua New Guinea, where carbon dioxide bubbles into the water from the slopes of a dormant volcano.

This local acidity is too much for most corals; instead, an alternative ecosystem based on seagrasses thrives.

With carbon emissions continuing to rise, researchers predicted most reefs around the world would be in serious trouble before the end of the century.

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