Stephen Giovannoni, Ph.D.
Oregon State University
The need for strategic changes in metrics of microbial diversity.
Wednesday — April 18, 2012
Pacific Forum — 3:00 p.m.
Ocean microorganisms catalyze chemical reactions in a complex network of processes that impact global chemistry and ecology. These processes are often attributed to guilds of organisms that have fundamentally similar biochemistry. For example, all photosynthetic organisms that make oxygen share a common core of metabolism. But, biogeochemical processes are driven by more than thermodynamics; evolutionary history, culminating in the ecology of modern plankton, affects all aspects of ocean biogeochemistry.
Moving from models that break microbial diversity into guilds to more complex models that take into account niche partitioning and interactions is a goal of modelers because of the hope it will explain more of the observed variance in processes. A key issue that stands in the way is lack of agreement about methods for assessing microbial diversity. This lack of agreement makes it difficult to compare data from different ocean sites for the purpose of identifying shared patterns, and it has affected all aspects of microbial diversity measurements, including metagenomics. This lecture examines the underlying assumptions behind tools commonly used to assess microbial diversity and recommends strategies for organizing microbial diversity information according to the need for functionally significant units for comparison.