Posted on EPOCA: 06 Oct 2011
The rise of carbon dioxide in the atmosphere from human activities has been significantly slowed by the oceans, which have absorbed almost half of all the industrial CO2 emissions to date. Chemical reactions between this anthropogenic CO2 and seawater lead to a reduction in carbonate ion concentration and an increase in hydrogen ions, thus making the ocean more acidic. The rate of acidification is spatially variable, reflecting patterns in chemical buffering of seawater and the physical currents that transport acidified water from the surface ocean to depth. There are several important consequences of ocean acidification. The loss of carbonate ions reduces the chemical capacity of the oceans to further absorb CO2 from the atmosphere, so that future oceanic CO2 uptake will become predictably less efficient. A wide variety of biochemical and physiological processes are also directly altered by changes in ocean pH and CO2 levels, but the consequences are less predictable. While many of these have been well studied at an organism scale, understanding their aggregated impact on marine ecosystem functioning is just beginning. Like the rate of acidification itself, the responses of major species and ecosystems are likely to be geographically heterogeneous. To set the stage for presentations on the biological and societal implications of ocean acidification, I will review the fundamental chemical and physical processes by which this major chemical perturbation will spread through the ocean in this century.
Kavli Frontiers of Science, Vimeo, 6 October 2011. Video.