Acidifying Oceans Major Threat to Entire Marine Food Web
08.02.2010 - Atmosphere & Space, Water & Oceans, Flora & Fauna, Bi-polar
Atmospheric CO2 is causing climate change worldwide, and the world’s oceans are no exception to the rule. As a natural sink for CO2, the oceans absorb the gas from the atmosphere. However as CO2 concentrations increase, this increases the acidity of seawater, as the absorption of CO2 leads to an increase in the release in hydrogen ions.
By collecting and reviewing the most recent data on ocean acidification at high latitudes for an article in Oceanography magazine, scientists from the University of Alabama at Brimingham were able to find that the delicate balance of life in Antarctic waters is especially susceptible to the effects of acidification.
The pH-levels in the data collected since the pre-industrial age indicate that the mean surface pH of the oceans has declined from 8.2 to 8.1 units (keeping in mind the pH scale is logarithmic and that seawater is naturally slightly basic). Since another 0.4 unit decline is possible by the end of this century, very fundamental biological processes could be influenced by ocean acidification, as evolution might be simply too slow to keep up with the changing environment.
One of the main consequences of this acidification would be that the availability of minerals used by marine invertebrates such as mollusks and crustaceans to create their protective shells would be at risk. A post-mortem study conducted on shells of Antarctic marine invertebrates showed evidence of erosion and subsequent loss of mass within only five weeks under simulated acidic conditions.
With this phenomenon putting increased stress on various mollusks and crustaceans, acidification could have a significant negative impact on the world's fisheries and alter the oceans' long-standing food chains.
