Zhou, J. Oak Ridge National Laboratory, zhouj@ornl.gov
Palumbo, A. Oak Ridg National Laboratory, palumboav@ornl.gov
O'Neill, R. V. Oak Ridge National Laboratory, oneillrv@ornl.gov
Xia, B. Center for Microbial Ecology,,
Figueras, J. B.. Institute of Aquatic Ecology,
Tiedje, J. M. Center for Microbial Ecology, tiedjej@pilot.msu.edu

In comparing microbial diversity in different environments it is apparent that spatial heterogeneity may play a key role in shaping diversity. The importance of spatial heterogeneity has long been recognized in diversity of higher organisms particularly at the landscape level. In microbial communities this effect may be evident at much smaller scales. The potential importance of spatial heterogeneity and connectivity in controlling competition, and thus diversity, can be observed in comparison of the diversity of 16S rRNA sequences from DNA extracted from aquatic systems, subsurface terrestrial sediments, and surface soils. The upper anaerobic hypolimnion of Wintergreen Lake and subsurface terrestrial sediments were characterized by high species richness and relatively low equitablity. However, terrestrial surface samples were characterized by an extremely even distribution. Spatial heterogeneity and the lack of connectedness of these unsaturated surface soils may be key factors in preventing competition and thus limiting dominance in these systems. The connectedness of the environment in the hypolimnion and the saturated sediments allows for competitive interactions which are inhibited by the spatial isolation in the surface. Studies in other environments such as saturated surface soils (e.g., rice paddy soils) or in the guts of invertebrates (where the spatial isolation would be destroyed by mixing) could provide further tests of this hypothesis
Day: Tuesday, Feb. 2
Time: 12:15 - 12:30pm
Location: Hilton of Santa Fe
Code: SS40TU1215H