Biddanda, B. A. Department of Ecology, University of Minnesota, bidda001@tc.umn.edu
Ogdahl, M. A. Department of Ecology, University of Minnesota, ogdahl@stud.ntnu.no
Cotner, J. B.. Dept. Ecology, University of Minnesota, cotne002@tc.umn.edu

 
CARBON FLUX THROUGH BACTERIOPLANKTON IN LAKES AND THE OCEAN: REGULATION BY SYSTEM PRODUCTIVITY
 
Heterotrophic bacteria are known to make significant contributions to the biomass and activity of plankton in lakes as well as the ocean. Whereas it is commonly accepted that bacterial life in the aquatic milieu is somehow a function of primary productivity, the way in which this relationship functions and extends throughout fresh and marine environments is unclear. During the summer of 1998, we quantified bacterial composition and measured bacterial growth and respiration in several small Minnesota lakes as well as the Great lakes and compared these findings with similar studies from the Gulf of Mexico. In lakes as well as the sea, bacteria were a large reservoir of total plankton Carbon and Nitrogen (20 - 70%) with their contribution being higher in oligotrophic than in eutrophic waters. Further, the bacterial contribution to total plankton respiration ranged from 10 - 90%, with higher percentages occurring in oligotrophic waters. In both fresh water and marine environments, the realtive contribution of bacteria to plankton biomass as well as metabolism is greater in oligotrophic waters than in eutrophic ones. Understanding this system-wide pattern of how ecosystem primary productivity regulates bacterial abundance and activity will be of key importance in biogeochemical studies.
 
Day: Wednesday, Feb. 3
Time: 08:30 - 08:45am
Location: Hilton of Santa Fe
 
Code: SS38WE0830H