Rising CO2 levels: Researchers warn of consequences of ocean acidification

Rising CO2 levels: Researchers warn of consequences of ocean acidification

Monday, September 23, 2013

The carbon dioxide increase in the atmosphere, the oceans will be more acidic. This not only damages the coral. An analysis of more than 160 studies shows that all the species composition of the oceans could change.

Coral and fish (Great Barrier Reef): threat of high CO2 levels

Bremerhaven / London - The acidification of the oceans will alter marine ecosystems throughout the century possibly profound. Corals, echinoderms, molluscs and crustaceans and fish - in all groups according to a new study, there are species that are vulnerable to climate change due to increased uptake of carbon dioxide in the sea water. The report scientists from the Alfred Wegener Institute (AWI) for Polar and Marine Research in Bremerhaven in the journal "Nature Climate Change" .Probably will in the long term, the species composition of the oceans change.

Ocean acidification is a consequence of increased carbon dioxide emissions into the atmosphere. The oceans absorb namely good on a quarter of the CO2 emitted. In the water, the carbon dioxide reacts to form carbonic acid. This lowers the pH of the water, the oceans are becoming more acidic. Experts estimate that the pH of the oceans by 2050 to decline by about 0.26 units below the pre-industrial value. By the end of the 21st Century is a decrease by 0.4 to 0.5 units possible - depending on how much carbon dioxide emissions is increasing worldwide.

Suffer coral, starfish and sea urchins

Researchers have pointed out in recent years that this will probably have consequences for sea life and already established effects on individual species. The total extent of the threat is so far not well studied. Astrid Wittmann and Hans-Otto Pörtner then assessed 167 scientific studies in which a total of 153 species were considered. "For example, we examined whether the metabolism, growth, calcification or change the behavior at elevated carbon dioxide concentrations," explains Pörtner.

The re-evaluation showed that in the invertebrates, especially corals, molluscs and echinoderms, such as starfish and sea urchins are suffering under the acidification. The sea creatures literally dissolve . Crustaceans appear to be robust, however. That the different animal groups responded differently to the acidification stems from the fact that their body functions differed so fundamentally, the scientists write. Fish could compensate, for example, decreasing pH levels in her blood again.However, physiological mechanisms lacked the coral to compensate for carbon dioxide levels increased. This affects, for example, the calcification.