Ocean Acidification Threatens Over 1 Million Species

May 26, 2009

Ocean acidification is the name given to the ongoing decrease in the pH of the Earth’s oceans, caused by their uptake of anthropogenic carbon dioxide from the atmosphere. Scientific data collected over many years are conclusive that oceanic absorption of atmospheric CO2 is causing chemical changes in seawater, making them more acidic (i.e. lowering pH). Increasing levels of anthropogenic CO2 are causing this process to accelerate. The average pH of the world’s oceans has dropped by about 0.1 pH units since the beginning of the industrial age. Being a logarithmic scale, this equates to increased acidity of about 30 per cent. Without deep and early reductions in global carbon emissions, oceanic uptake of anthropogenic carbon will result in a further drop of 0.3 to 0.7 pH units by the year 2100. The degree and rapidity of these changes in ocean chemistry have not occurred in millions of years.

Early data is highly suggestive that ocean acidification will negatively impact many important marine organisms. Lower pH interferes with the physiological processes of calcifying organisms, including corals, echinoderms, coccolithophores, mollusks, and some zooplankton, which use various forms of calcium carbonate to construct cell coverings or skeletons. Scientists agree that ocean acidification, if allowed to continue, will be devastating for corals. Leading coral reef scientist J. E. N. Veron was recently quoted saying that if we don’t drastically reduce carbon dioxide emissions in the next 20 years, by the middle of the century there will be no coral reefs developing anywhere due to ocean acidification. There is no time to waste; we must start reducing emissions now.

Corals and calcifying organisms aren’t the only marine life affected by ocean acidification. Fish may also suffer adverse effects from acidification, either directly as reproductive or physiological effects (e.g. CO2-induced acidification of body fluids), or indirectly through negative impacts on food resources. There is not yet a clear understanding of these processes, their implications for marine ecosystems, or for the human societies and economies that depend on marine resources and services. Given the critical ecological, economic, and cultural function of oceans in the region, nowhere is the need for additional research greater than the Asia-Pacific.

The ocean naturally absorbs CO2 as part of what’s known as the carbon cycle. Here’s how it works: the oceans absorb an enormous amount of carbon dioxide from the atmosphere, which reacts with sea water to produce carbonic acid.

Source: Save the Ocean

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