Coastal bacteria and protists assimilate viral carbon and nitrogen

Journal Article · 13 November 2024 · The ISME Journal

DOI: https://doi.org/10.1093/ismejo/wrae231 · OSTI ID:2480762

Martínez Martínez, Joaquín ^[1]; Talmy, David ^[2]; Kimbrel, Jeffrey A. ^[3]; Weber, Peter K. ^[3]; Mayali, Xavier ^[3]

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1. Bigelow Laboratory for Ocean Sciences, East Boothbay, ME (United States); Univ. of Maryland Center for Environmental Studies, Cambridge, MD (United States)
2. Univ. of Tennessee, Knoxville, TN (United States)
3. Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)

Free viruses are the most abundant type of biological particles in the biosphere, but the lack of quantitative knowledge about their consumption by heterotrophic protists and bacterial degradation has hindered the inclusion of virovory in biogeochemical models. Using isotope-labeled viruses added to three independent microcosm experiments with natural microbial communities followed by isotope measurements with single-cell resolution and flow cytometry, we quantified the flux of viral C and N into virovorous protists and bacteria and compared the loss of viruses due to abiotic vs biotic factors. We found that some protists can obtain most of their C and N requirements from viral particles and that viral C and N get incorporated into bacterial biomass. We found that bacteria and protists were responsible for increasing the daily removal rate of viruses by 33% to 85%, respectively, compared to abiotic processes alone. Our laboratory incubation experiments showed that abiotic processes removed roughly 50% of the viruses within a week, and adding biotic processes led to a removal of 83% to 91%. Our data provide direct evidence for the transfer of viral C and N back into the microbial loop through protist grazing and bacterial breakdown, representing a globally significant flux that needs to be investigated further to better understand and predictably model the C and N cycles of the hydrosphere.

• Research Organization: Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)
• Sponsoring Organization: USDOE; USDOE National Nuclear Security Administration (NNSA)
• Grant/Contract Number: AC02-05CH11231; AC52-07NA27344
• OSTI ID: 2480762
• Report Number(s): LLNL-JRNL--865560; 1099447
• Journal Information: The ISME Journal, Journal Name: The ISME Journal Journal Issue: 1 Vol. 18; ISSN 1751-7362
• Publisher: Nature Publishing GroupCopyright Statement
• Country of Publication: United States
• Language: English