PARENT SESSION
Oral Session #41: Biodiversity and Ecosystem Function I.
Presiding: J. Callaway
Tuesday, August 6. 1:00 PM to 4:45 PM. Coconino Meeting Room, TCC.
The effect of productivity on bacterial diversity.
Devine, M. Claire*,1, Leibold, Mathew2, Bohannan, Brendan1, 1 Department of Biological Sciences, Stanford, CA2 Department of Ecology and Evolution, Chicago, IL
ABSTRACT- One of the most fundamental patterns in ecology is the relationship between the number of species and the amount of available energy in a given area in the environment. This relationship may underlie some of the most striking patterns in plant and animal diversity, such as the relationship between species richness and latitude or species richness and altitude. However, virtually nothing is known about how bacteria vary along environmental energy gradients. We assessed bacterial diversity in aquatic mesocosms maintained at different nitrogen and phosphorous levels, which corresponded to different levels of algal productivity. The mesocosms consisted of large cattle tanks (five feet in diameter) containing pond water with algae and microorganisms. We measured bacterial taxonomic richness in these mesocosms by amplifying, cloning and sequencing a variable region of bacterial 16S rDNA. Neither total bacterial richness nor observed algal richness showed a relationship with chlorophyll a. In contrast, estimated richness of three major bacterial subgroups exhibited three different trends with increasing chlorophyll a. Bacterial richness showed an increasing trend with increasing nutrients while algal richness was a unimodal function of nutrient levels. Our results show that productivity and nutrient levels differentially influence bacterial and algal communities.
KEY WORDS: productivity, microbial diversity, bacterial community composition, eutrophication