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The "Other" Side of Climate Change: Rising CO2 and Marine Life
15 Nov, 2007 02:22 pm
Professor Ulf Riebesell, of the Department of Biological Oceanography at Leibniz Institute of Marine Sciences at the University of Kiel, studied the "other" side of climate change: the effect of increasing atmospheric carbon dioxide (CO2) and ocean acidification on marine life. He speaks to Scitizen.com regarding his related experiments in the Norwegian fjords.
Prof. Ulf Riebesell: As carbon dioxide increases in the atmosphere and thereby increases in the surface ocean, phytoplankton take up more CO2 into their biomass, so their agrobiomass increases in CO2 content.
S: You experimented with the potential situation in 2100 and 2150. What do you forecast?
UR: [Through] simulation [of expeted] conditions provided that we continue with CO2 emissions, what we see is that through biological fixation of CO2, there will be increased carbon sequestration in the ocean under future conditions...
S: What are the results for our oceans and environment?
UR: The consequences of increased carbon fixation is that carbon-rich phytoplankton, as they sink to the deep ocean, become re-mineralized (a typical process that happens), and the more carbon they contain, the more oxygen is consumed by re-mineralizing the oganic matter...This is bad news for all higher life in the deep oceans, because all higher organisms require oxygen to live; in fact, our results and some model work... shows that oxygen in depleted areas of the ocean will greatly enlarge in other areas of the ocean. The other [negative side effect] is that the extra CO2 that is transported to the deep ocean will increase the CO2-induced acidification of the deep ocean. Right now, it is mainly on the surface ocean, which by taking up massive amounts of man-made CO2, slowly acidifies. But the deep ocean is not directly affected, because mixing with the deep ocean is very slow. However, the process that we have now seen will accelerate the acidification of the deep ocean...
S: Why did you choose Norway as a site of study?
UR: A very simple logistical reason: there is a very well-kept mesocosm facility in this location, south of Bergen in Norway...
Riebesell U, Schultz KG, Bellerby RGJ, et al. Enhanced biological carbon consumption in a high CO2 ocean. Nature, 11 November 2007. Available here.
Interview by Audrey Wang