Abstract
Sinking particles and particle-associated microbes influence global biogeochemistry through particulate matter export from the surface to the deep ocean. Despite ongoing studies of particle-associated microbes, viruses in these habitats remain largely unexplored. Whether, where, and which viruses might contribute to particle production and export remain open to investigation. In this study, we analyzed 857 virus population genomes associated with sinking particles collected over three years in sediment traps moored at 4000 m in the North Pacific Subtropical Gyre. Particle-associated viruses here were linked to cellular hosts through matches to bacterial and archaeal metagenome-assembled genome (MAG)-encoded prophages or CRISPR spacers, identifying novel viruses infecting presumptive deep-sea bacteria such as Colwellia, Moritella, and Shewanella. We also identified lytic viruses whose abundances correlated with particulate carbon flux and/or were exported from the photic to abyssal ocean, including cyanophages. Our data are consistent with some of the predicted outcomes of the viral shuttle hypothesis, and further suggest that viral lysis of both autotrophic and heterotrophic prokaryotes may play a role in carbon export. Our analyses revealed the diversity and origins of prevalent viruses found on deep-sea sinking particles and identified prospective viral groups for future investigation into processes that govern particle export in the open ocean.
Highlights
IntroductionMicrobes fuel the biological carbon pump by reducing inorganic carbon to organic carbon, some of which sinks into the deep sea in aggregates of both organic and inorganic particulate matter [1, 2]
A total of 184 deep trap viruses (DTVs) were tentatively identified as temperate phage, using genomic markers for lysogeny
Since only 0.8% of DTVs appeared derived from eukaryotic viruses (7 total), we focused our analyses on prokaryote viruses, 95 of which were linked to hosts through metagenome-assembled genome (MAG) and reference databases
Summary
Microbes fuel the biological carbon pump by reducing inorganic carbon to organic carbon, some of which sinks into the deep sea in aggregates of both organic and inorganic particulate matter [1, 2] These sinking particles and their associated microbes play a critical role in the global carbon cycle by sequestering approximately 4 gigatons of our planet’s atmospheric carbon annually [3], roughly equivalent to the total standing carbon stock in marine biomass [4]. Sinking particles represent “hotspots” of microbial activity, harboring diverse assemblages that play active roles in the transformation of organic matter in the oceans [5–11]. These microbial communities connect the surface and deep oceans [12] and fuel biogeochemical cycling through selective remineralization of labile organic carbon [13]. Sinking particles are enriched in larger “copiotrophic” bacteria typically associated with gut microbiomes, such as Bacteroidetes, δ-, ɛ-, and γproteobacterial groups [8–11, 15–20]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
