Sarah Hu, WHOI, March 24, 2021
Title: The Impact of Phagotrophic Protists at Hot Spots of Primary Production in the Deep Sea
Abstract: Microbial eukaryotes (or protists) in marine ecosystems are a link between microbial primary producers and all higher trophic levels. The rate at which heterotrophic protistan grazers consume microbial prey and recycle organic matter is an important factor that influences marine microbial food webs and carbon cycling. At deep-sea hydrothermal vents, chemosynthetic bacteria and archaea form the base of a food web that functions in the absence of sunlight, but the role of protistan grazers in these highly productive ecosystems is largely unexplored. Here, I will present findings from paired grazing incubations and molecular surveys and address the ecological significance of protists at deep-sea hydrothermal vents. In addition to quantifying protistan predation pressure, these results highlight the impact that the protist community has on deep-sea carbon cycling.