January 18 2012

12:00 LSB 2320

Jennifer Martiny
Ecology & Evolutionary Biology, University of California, Irvine

Microbial Biogeography and Why it Matters


Although it is generally accepted that plant community composition is key for predicting rates of ecosystem processes, microbial community composition is often ignored in ecosystem and global change models. In part, this is because we know relatively little about the biogeography of microorganisms. In the first half of the talk, I will present a study that examines bacterial beta-diversity from centimeter to continental spatial scales. The study surveyed beta-Proteobacteria from salt marsh sediments on three continents. We found that the drivers of this beta-diversity, including dispersal limitation and environmental selection, varied by spatial scale. In the second half of the talk, I will present a framework for testing whether such variation matters for ecosystem functioning. In particular, I propose that one needs to know whether microbial communities are resistant, resilient, and functionally redundant. To test the idea of functional redundancy in estuarine bacterial communities, we reciprocally transplanted sediments between salt and freshwater sites along a river. The results suggest that shifts in microbial composition due to environmental changes can directly influence ecosystem functioning. Thus, microbial composition may help to predict the responses of ecosystem processes to global change.











































































































































































































































































































































































































































































































































































































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