The Sylvan lab at Texas A&M University studies the geomicrobiology and biogeochemistry of deep ocean hydrothermal ecosystems and the deep biosphere in subseafloor basaltic crust. We address fundamental questions about the biology, chemistry and geology of the Earth through the study of interactions between the ocean crust and the marine biosphere. We are also interested in the microbiology and biogeochemistry of our own backyard, the Gulf of Mexico, where we are currently studying interactions between oil, dispersants and microbial populations.