Environmental Climate Change : The role of marine and aquatic photosynthetic organisms in the global carbon cycle
Raven, John A. .
Ocean acidification: photosynthetic organisms as victims and beneficiaries - and saviours?
Continuing ocean acidification occurs as a result of anthropogenic CO2 release to the atmosphere with about a quarter dissolving in the ocean, increasing the CO2 and H2CO3 concentrations, increasing the HCO3- concentration relatively less (but more in absolute terms), and decreasing the CO32- concentration. Growth of many non-calcified marine photosynthetic organisms is saturated by the present concentration of inorganic carbon species in the surface ocean. Other non-calcified photosynthetic organisms such as some phytoplankton species and a number of macroalgae and seagrasses, with a less effective or no CO2 concentrating mechanism, show increased growth when more CO2 is added to present-day seawater. For calcified photosynthetic organisms (e.g. coccolithophores, and symbiotic foraminifera and corals) there is the additional complication that in many cases calcification, and thus growth, is decreased when carbon dioxide is supplied at greater than the present levels. With the additional complication of warming of the surface ocean with less deep mixing, and so a smaller input of nutrients regenerated in the deep ocean, it is difficult to predict the outcome of global environmental change for marine primary productivity, though species composition will change and there may be a decrease in the oceanic ecosystem services provided by photosynthetic organisms. Fertilization of iron- and of nitrogen-limited areas of the ocean with the respective limiting nutrient has been proposed and, for iron, tested as a means of bioremediation of both ocean acidification and increased atmospheric CO2. However, major remediation is unlikely to occur, and there could be undesirable side effects.
Log in to add this item to your schedule
1 - University of Dundee , Division of Environmental and Applied Biology, Biological Sciences Institute, Dundee DD1 , 4hn, Scotland, UK
global carbon cycle
oceanic carbon cycling.
Presentation Type: Symposium or Colloquium Presentation
Location: Cottonwood B/Snowbird Center
Date: Wednesday, July 29th, 2009
Time: 9:00 AM