Marine Microbial Biogeochemistry
Our Research
Research in my group centers on measuring what marine microorganisms actually do: bacterial production, respiration and dark carbon fixation. We study these processes across the water column and at two of the ocean's most dynamic yet understudied interfaces, the sea-surface microlayer at the air-sea boundary and the benthic nepheloid layer near the seafloor. Linking these rate measurements to community structure and functional genes connects who is present with what they are doing, and how this shapes the ocean's biogeochemical cycles.
One research line targets the near-bottom nepheloid layer, where resuspended particles keep the water turbid, to ask how this resuspension affects organic matter breakdown just above the sediment. A second follows the ocean's surface film, where UV exposure and altered chemistry shape microbial activity right at the air-sea interface.
What is it about?
They are invisible to the naked eye, yet they are everywhere. With microscopy and special staining techniques, we can reveal microbes measuring just one micrometer or less, and what we find is astonishing.
A single cubic centimeter of seawater typically contains more than one million of these microscopic organisms. Scaled up to the global ocean, which covers 71% of Earth’s surface, their numbers become almost incomprehensible. But sheer abundance is only part of the story: microbes are also biochemical engines, continuously converting dissolved organic carbon into living biomass and carbon dioxide. This makes them one of the most consequential biological forces on the planet.
We have learned a great deal about what microbes do in the ocean, but we are only beginning to understand how they do it. Unraveling the intricacies of their ecology is not merely an academic exercise. It is a prerequisite for understanding, and ultimately predicting, how our climate will change in the decades ahead.
