Marine Biology Seminar: Dr. Anne Dekas (Stanford University)
"Microbial activity in the dark ocean: who is doing what, and how much?"
Abstract: The dark ocean is one of the largest habitats for microbial life on the planet: it covers nearly two thirds of our Earth’s surface and harbors well over half of marine microorganisms. The activity of microorganisms in the deep sea plays an essential role in biogeochemical cycling, including the production and consumption of greenhouse gases (e.g., CH4, CO2 and N2O), thereby affecting climate. The goal of my research is to understand the activity of bacteria and archaea in the dark ocean: who is doing what, how much, and what affects metabolic rates? In this talk, I will describe two lines of research, one investigating nitrogen fixation in deep-sea sediments, and one probing organic substrate utilization by pelagic marine Thaumarchaeota. Additionally, I will describe the culture-independent techniques we employ, including recent methodological advances in the use of nanoscale secondary ion mass spectrometry (nanoSIMS) to quantify anabolic activity in uncultured microorganisms on the single-cell level.