March 8, 2012
Dr. Beth Orcutt, Aarhus University
The Dynamics of Life Across the Sediment-Basement Interface
Previous studies of microbial abundance and geochemistry in deep marine sediments indicate a stimulation of microbial activity near the sediment-basement interface – the boundary between the two largest potential habitats for microbial life on Earth. The few studies thus far conducted in deep oceanic crust reveal an active microbial community in this habitat; yet the extent to which microbial communities in bottom sediments and underlying crustal habitats interact is unclear. I am interested in investigating whether microbial communities in deep sediments are seeded and/or stimulated from basement communities, or vice versa. If there is influence from one habitat type on the other, how far does this influence extend, both with vertical distance away from the interface and laterally along the flow path of fluids within basement? I will present an overview of several on-going biogeochemical and molecular biological studies to examine the nature of microbial life across the sediment-basement interface, focusing on recent expeditions to the Juan de Fuca Ridge and Mid-Atlantic Ridge flanks (IODP Expeditions 327 and 336, respectively).
Dr. Orcutt was a postdoctoral research associate at the Center for Geomicrobiology at Aarhus University, Denmark. Starting in April 2012, she is a Senior Research Scientist at the Bigelow Laboratory for Ocean Sciences. Her research interests include geomicrobiology and microbial biogeochemistry of marine sediments, ocean crust and the deep subsurface; and determining fundamental links between microbial diversity, activity and environmental variables.