Abstract:Most aspects of climate change are associated with changes in atmospheric compostion that affect the Earth's radiative budget. There is yet another aspect of increaing CO2 levels in the atmosphere, and that is the change in seawater chemistry associated with the ocean's uptake of atmospheric CO2 across the air-sea interface. As atmospheric CO2 concentrations rise to levels not seen for at least a half-million years, the carbonate system in seawater is also shifting to an unprecedented state. The main consequences are a lowering of both pH and carbonate ion cencentration, and a lowering of the saturation states of the minerals calcite and aragoninte(CaCO3), the main skeleton-forming minerals for many marine organisms. One of the demonstrated biological consequences of ocean acidification is a reduction in calcification rates, which if true, could have serious effects on individual organisms and the ecosystems in which they live. The ultimate fear is that ocean acidification will lead to a marine biological crisis, while the ultimate hope is that organisms will adapt to these changes. This talk will highlight what is known about ocean acidification and its effects on marine organisms, and will attempt to put these fears and hopes in perspective. |
