O'Reilly, C. M. University of Arizona, coreilly@geo.arizona.edu
Cohen, A. M. University of Arizona, acohen@geo.arizona.edu

 
IMPLICATIONS OF LAND USE CHANGE FOR LAKE PRODUCTIVITY: DEFORESTATION IN LAKE TANGANYIKA, EAST AFRICA
 
Lake Tanganyika, East Africa, is purported to have one of the most productive freshwater ecosystems and is an important natural resource for the surrounding communities. Growing pressure for fuel, timber, and land for agriculture has led to extensive deforestation within the catchment. The subsequent erosion has many potentially negative consequences for the flora and fauna of the lake. By comparing two adjacent watersheds with contrasting land use patterns, we investigated the effect of deforestation on the littoral zone of Lake Tanganyika. The results show that increased erosion at the disturbed site is affecting benthic productivity. Biomass of benthic algae is much greater at the disturbed site, and biomass specific net productivity is lower. Greater suspended sediment has decreased light penetration, and a layer of sediment blankets much of the rock surface. Lower ambient oxygen levels at this site suggest an increase in biological oxygen demand. In addition, there is evidence to suggest that biodiversity is lower relative to the forested site. This environmental degradation could have a significant impact on upper trophic levels, including some of the fish species in the lake that are important both economically and as a protein source for the local population.
 
Day: Tuesday, Feb. 2
Time: 10:30 - 10:45am
Location: Sweeney Center
 
Code: SS07TU1030S