Biogeochemistry is an interdisciplinary science that examines the role of biological processes in mediating the geological and chemical dynamics of the Earth's atmosphere, hydrosphere, and lithosphere. The integrative nature of biogeochemical studies requires the application of tools from a variety of scientific disciplines including microbiology, biochemistry, geochemistry, ecology, hydrology, mathematics, and physics.

Biogeochemical research in the Department of Marine Sciences focuses on:

> Cycling of nutrients (N, P), carbon, oxygen, sulfur, and trace metals (Cai, Hollibaugh, Joye, Meile, Miller, Sun, Zhang)

> Trace gas cycling and emission to the atmosphere (Cai, Joye, Miller)

> Biogeochemistry of extreme environments (a.k.a. astrobiology), e.g., saline lakes, methane hydrates and cold seeps (Hollibaugh, Joye, Meile, Zhang)

> Groundwater inputs to coastal systems (Cai, Joye, Meile)

> Mangrove and salt marsh biogeochemistry (Cai, Joye, Meile, Miller)

> Degradation of organic matter (Hodson, Miller, Moran)

> Role of marine microrganisms in global climate (Hollibaugh, Miller, Moran, Yager)

> Sediment diagenesis, organic matter degradation/preservation, and benthic biogeochemical processes (Cai, Joye, Meile,  Sun, Zhang)

> Biomarker and molecular isotope application in geochemistry (Sun, Zhang)

> Biogeochemical modeling, remineralization, trace-metal scavenging, particle flux and their impacts on the global climate (Burd)

> Aquatic photochemistry, environmental optics, and remote sensing (Miller)