HR: 0800h
AN: GC51D-1076    [Abstracts]
TI: Climate Change Affects the East African Rift Valley Lakes
AU: * O'Reilly, C M
EM: caoreilly@vassar.edu
AF: Environmental Science Program Vassar College, 124 Raymond Ave, Poughkeepsie, NY 12604 United States
AU: Plisnier, P
EM: pierre-denis.plisnier@arcadis.be
AF: Royal Museum for Central Africa, 3080 Tevuren, Namur, B-5000 Belgium
AU: Plisnier, P
EM: pierre-denis.plisnier@arcadis.be
AF: Department of Biology, Namur University, Namur, B-5000 Belgium
AU: Cohen, A S
EM: acohen@geo.arizona.edu
AF: Department of Geosciences University of Arizona, 1040 E 4th St, Tucson, AZ 85721 United States
AB: Over the last 100 years, air temperatures in eastern African have been warming consistent with the global average temperature increase. This has led to warmer water temperatures in the East African Rift Valley lakes, increasing the stability of the water column. Subsequently, there has been a reduction in the upwelling of deep nutrient-rich waters that are the primary source of nutrients for most of these lakes. There were decreases in surface water N and P and increases in the Si:P ratio over the past 70 years for Lakes Malawi, Tanganyika, Edward, and Albert. The lower nutrient concentrations in the surface waters were associated with reduced algal biomass and increased water clarity. The consistent, regional-scale changes among these lakes provide strong evidence that climate warming may be having a large negative affect on these unique tropical lakes. A decrease in primary productivity of 20% has been indicated for Lake Tanganyika, which would be associated with a 30% decrease in fisheries yields. The human implications of such subtle, but progressive, environmental changes are potentially dire in this densely populated region of the world, where these large lakes are an important nutritional and economic resource.
DE: 1845 Limnology
DE: 1615 Biogeochemical processes (4805)
DE: 1630 Impact phenomena
SC: Global Climate Change [GC]
MN: 2004 AGU Fall Meeting