Microbial Ecology

A Sea of Microbes

The oceans are dominated by microbial ecosystems. Microscopic organisms represent more than 90% of biomass in the oceans, including the majority of the primary producers – photosynthetic organisms ­– that form the base of ocean food webs.

Yet, scientists have only come to appreciate the enormous abundance of bacteria in the oceans in the last 40 years or so. And we still have relatively little understanding of their diversity and the varied roles they play in driving biogeochemical processes that ultimately sustain all life in the ocean and control the composition of our atmosphere.

Unveiling Genetic Diversity

Important efforts in the last few years have focused on unveiling the genetic diversity contained within ocean microbes. The conceptualization of this community as regulated by a “meta-genome” represents a major shift in our approach to environmental biology. Microbial community genome data can be used to predict and verify relevant biotic interactions, functional properties, and biogeochemical capabilities.

The basic premises of these efforts are that decoding the genetic inventory (the information that shapes ecosystems) enables us to unravel the complex biogeochemical interactions within complex systems. These approaches are especially powerful if combined with the study of model organisms – single species studied in depth in the laboratory and in the field – to elucidate ecological and evolutionary processes and dynamics. With the advent of new fast and cheap DNA sequencing technology, we are poised for major advances in the coming years.

Key Questions We’re Exploring

• What sets the pattern and structures of microbial communities in the ocean?
• How do pathogenic bacteria affect marine communities?
• How much genetic diversity can be found within a single species and what role does this play in the stability of ecosystems?
• How much gene exchange occurs among different species?
• What is the role of viruses in microbial diversity and genetic composition?
• How can we predict community composition from chemical and physical parameters?
• How can we model microbes at cell and population levels?