Viral impacts on microbial carbon cycling at deep-sea hydrothermal vents

Within microbial communities, viruses infect cells and release organic carbon from primary producers into dissolved and particulate carbon pools in the ocean. Despite the key role of viruses in the ocean, linking their diversity to their function remains a challenge. This challenge is especially amplified in the undersampled deep ocean, where primary producers and their viruses are understudied relative to microbes in the surface ocean. In this project the investigators are identifying the key viral players and the processes by which they affect microbial carbon cycling in the dark ocean. In addition, the investigators are mentoring postdoctoral and undergraduate students and integrating their scientific findings into media products such as podcasts to share discoveries about “viruses in the wild” to inspire public interest in deep-sea exploration and microbial oceanography. In this project, the researchers are studying the diversity, mechanisms, and rates of virus-induced carbon cycling in a deep-sea hydrothermal vent system. While chemoautotrophic microbes are known to contribute to these hotspots of primary productivity, the functional role and biogeochemical impacts of viruses that infect them remain critical gaps in our understanding of the dark ocean’s carbon cycle. The researchers combine metagenomics with stable isotope probing (SIP) to identify links between metagenomic diversity and ecological function. They combine carbon-13 stable isotope probing (13C-SIP) with metagenomics, nanoscale secondary ion mass spectrometry (NanoSIMS), and microscopy to reveal the diversity, activity, mechanisms, and rate of virus-induced carbon cycling, and they use targeted sequencing of both cellular and viral-particle samples, as well as quantitative SIP-metagenomics, to identify virus-host interactions underpinning key microbial processes regulating carbon cycling in 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.