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Project Progress

Subsurface Biospheres (dm)

A better understanding of the Earth’s deep biosphere is essential because it can serve as a model for life on other planets and it is a critical component of the Earth’s biogeochemical cycles. This reseaerch is aimed at gaining a fundamental understanding of the life in deeply buried marine sediments. We conduct an interdisciplinary set of projects that takes advantage of our considerable expertise in marine sedimentary microbiology, sedimentary biogeochemistry and deep ocean drilling. Our objectives are to understand the subsurface microbial ecosystems of marine sediments, their role in Earth’s biogeochemical cycles, and their relevance to the search for life on other planets. The first project explores the taxonomic composition, metabolic activity and geochemical consequences of buried microbial ecosystems in marine sediments with widely different physical and chemical characteristics. The second project documents the nature, extent and perturbation-sensitivity of microbial activity in marine sediments and the effect of that activity on Earth’s biogeochemical cycles of various chemical species, particularly sulfate and methane. The third project focuses on identifying signatures of present and past microbial processes in Earth’s subsurface as a guide to predicting such signatures in extraterrestrial subsurface environments.