MARINE MICROBIOMES AND VIROMES

The deep ocean is one of the planet’s largest biomes. In spite of cold temperatures and the lack of light, the deep-sea hosts abundant microbial life that play critical roles in the biogeochemical cycling of carbon, nitrogen, sulfur and other nutrients. At deep-sea hydrothermal vents, high temperature water-rock reactions catalyze the formation of chemically reduced vent fluids rich in sulfur species, hydrogen, methane, ammonia, manganese and iron. The reduced chemicals serve as electron donors to fuel chemosynthetic microbial metabolisms that form the base of the food chain in such ecosystems. In many ways, oxygen-minimum zones are similar to hydrothermal vents, characterized by a microbiome dependent on reduced chemicals especially sulfur.

We are studying the of impacts hydrothermal vents and oxygen minimum zones on the pelagic oceans through the lens of microbial ecology and biogeochemistry by conducting experiments, in situ measurements, and multi-omics.

We are a sea-going lab, actively undertaking field work with field sites around the world which allows us study marine processes are a variety of spatial scales.

Our field sites include:

1. Guaymas Basin hydrothermal system in the Gulf of California, Pacific Ocean
2. East Pacific Rise hydrothermal system in the Pacific Ocean
3. Lau Basin  hydrothermal system in the Pacific Ocean

Our work is highly collaborative and interdisciplinary. Our collaborators include Dr. Mandy Joye from the University of Georgia, Dr. Roland Hatzenpichler from Montana State University, Dr. Anna-Louise Reysenbach from Portland State University, Dr. Rika Anderson from Carleton College, and Dr. Elizabeth Trembath-Reichert from Arizona State University.

Viruses are an important control on marine microorganisms. Although viral abundance in the oceans is highest in the euphotic zones, viruses are also ubiquitous in the dark oceans. By lysing and turning over host microbial populations, viruses release dissolved organic matter, stimulate nutrient cycling, and directly influence global biogeochemical cycles. Marine viruses can also influence  and manipulate host metabolism via virally-encoded, host-derived auxiliary metabolic genes.

We are studying the ecology and evolution of marine viruses using hydrothermal viral communities and viruses of sulfur cycling microorganisms as model systems.

The subseafloor is home to one of the largest biomes on our planet. Subseafloor organisms live under intense pressure with access to limited nutrients and metabolic inputs, and can be very slow growing. Two abundant energy sources for subseafloor organisms include sulfur and methane.

In collaboration with Dr. Bill Reznikoff from the Marine Biological Laboratory, we are studying the ecological and evolutionary constraints on subseafloor microorganisms using sulfur cycling microorganisms as model systems.