Project: Collaborative Research: Microbes need frenemies: unveiling microbial relationships with protists and viruses that support deep-sea hydrothermal vent food webs

Non-technical abstract:
Ecological interactions among microbes (bacteria and archaea), viruses, and eukaryotic microorganisms are critical junctions in marine food webs. These interactions range from mutually beneficial relationships to sources of microbial mortality. Interactions between viruses-microbes and eukaryotes-microbes at deep-sea hydrothermal vents impact local carbon cycling. This project aims to identify these microbial interactions, specifically those related to cell death by protistan grazing or viral lysis, and explore how they vary across different hydrothermal vent habitats. By providing a better understanding of the composition and nature of these relationships, the investigators aim to build a better food web model of deep-sea hydrothermal vents and improve our understanding of how climate change and other human activities impact the ecosystem. Outcomes from this project include the generation of new microbiology, oceanography, and computer science curricula targeted at community college students. In addition, it involves research with undergraduate students at all stages of the research process and provides opportunities for professional development and peer-to-peer mentoring.

Technical abstract:
This project examines trophic interactions among microbial eukaryotes, viruses, bacteria, and archaea at deep-sea hydrothermal vents using metagenomics and metatranscriptomics and characterizes these ecologically-significant interactions, such as mutualism, predator-prey, or virus-host. The investigators are sequencing samples collected to target archaea/bacteria, viruses, and eukaryotic grazers during a 2020 expedition to the Mid-Cayman Rise hydrothermal vent field to accomplish these goals. Specific aims of this project are to 1) Investigate the microbial, viral, and protistan assemblages and determine how lifestyle, community composition, and metabolism vary across venting fluids of the Mid-Cayman Rise; and 2) Identify ecologically-significant interactions among protists, viruses, bacteria, and archaea and incorporate these interactions into a model for turnover and exchange of carbon in the vent-associated food web. By modeling how trophic interactions influence microbial mortality, the proposed project substantially contributes to our understanding of the fate of carbon in one of the most productive ecosystems of the deep sea.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.