CO2 emissions cause ocean acidification, threaten sea life
September 21, 2007
"Atmospheric CO2 concentrations need to remain at less than 500 ppm for the ocean pH decrease to stay within the 0.2 limit set forth by the U.S. Environmental Protection Agency ," said lead author Ken Caldeira from the Carnegie Institution Department of Global Ecology. "If atmospheric CO2 goes above 500 ppm, the surface of the entire ocean will be out of compliance with EPA pH guidelines for the open ocean. We need to start thinking about carbon dioxide as an ocean pollutant. That is, when we release carbon dioxide to the atmosphere, we are dumping industrial waste in the ocean."
Observed and projected decline in global ocean pH, 1750-2100. Photo by Rhett A. Butler
"About 1/3 of the CO2 from fossil-fuel burning is absorbed by the world's oceans," explained Caldeira. "When CO2 gas dissolves in the ocean it makes carbonic acid which can damage coral reefs and also hurt other calcifying organisms, such as phytoplankton and zooplankton, some of the most critical players at the bottom of the world's food chain. In sufficient concentration, the acidity can corrode shellfish shells, disrupt coral formation, and interfere with oxygen supply. "
Atmospheric CO2 levels presently stand at 380 ppm, but are expected to reach 500 ppm by mid-century. For comparison, pre-industrial concentrations were 280 ppm.
CITATION: Ken Caleira et al (2007). Geophysical Research Letters. September 25, 2007
Industrial pollution acidifies ocean, threatens marine animals Ocean acidification, already a concern due to rising levels of carbon dioxide, is worsening due to nitric acid and sulfuric acid from industry, report researchers writing in this week's issue of the journal Proceedings of the National Academy of Science (PNAS).
Some corals may survive acidification caused by rising CO2 levels
(3/29/2007) Several studies have shown that increased atmospheric carbon dioxide levels are acidifying the world's oceans. This is significant for coral reefs because acidification strips carbonate ions from seawater, making it more difficult for corals to build the calcium carbonate skeletons that serve as their structural basis. Research has shown that many species of coral, as well as other marine microorganisms, fare quite poorly under the increasingly acidic conditions forecast by some models. However, the news may not be bad for all types of corals. A study published in the March 30 issue of the journal Science, suggests that some corals may weather acidification better than others.
Carbon dioxide levels threaten oceans regardless of global warming
(3/8/2007) Rising levels of carbon dioxide will have wide-ranging impacts on the world's oceans regardless of climate change, reports a study published in the March 9, 2007, issue of the journal Geophysical Research Letters.
This article is based on a news release from Stanford University.