title: Virus decomposition provides an important contribution to benthic deep-sea ecosystem functioning.
abstract: Viruses are key biological agents of prokaryotic mortality in the world oceans, particularly in deep-sea ecosystems where nearly all of the prokaryotic C production is transformed into organic detritus. However, the extent to which the decomposition of viral particles (i.e., organic material of viral origin) influences the functioning of benthic deep-sea ecosystems remains completely unknown. Here, using various independent approaches, we show that in deep-sea sediments an important fraction of viruses, once they are released by cell lysis, undergo fast decomposition. Virus decomposition rates in deep-sea sediments are high even at abyssal depths and are controlled primarily by the extracellular enzymatic activities that hydrolyze the proteins of the viral capsids. We estimate that on a global scale the decomposition of benthic viruses releases ∼37-50 megatons of C per year and thus represents an important source of labile organic compounds in deep-sea ecosystems. Organic material released from decomposed viruses is equivalent to 3 ± 1%, 6 ± 2%, and 12 ± 3% of the input of photosynthetically produced C, N, and P supplied through particles sinking to bathyal/abyssal sediments. Our data indicate that the decomposition of viruses provides an important, previously ignored contribution to deep-sea ecosystem functioning and has an important role in nutrient cycling within the largest ecosystem of the biosphere.
authors.affiliation: Department of Life and Environmental Sciences, Università Politecnica delle Marche, 60131 Ancona, Italy; and a.dellanno@univpm.it.
authors.forename: Antonio
authors.initials: A
authors.lastname: Dell'Anno
authors.affiliation: Department of Life and Environmental Sciences, Università Politecnica delle Marche, 60131 Ancona, Italy; and.
authors.forename: Cinzia
authors.initials: C
authors.lastname: Corinaldesi
authors.affiliation: Department of Life and Environmental Sciences, Università Politecnica delle Marche, 60131 Ancona, Italy; and Stazione Zoologica Anton Dohrn, 80121 Naples, Italy.
authors.forename: Roberto
authors.identifier: http://orcid.org/0000-0002-9025-9395
authors.initials: R
authors.lastname: Danovaro
mesh_terms: D002244:Carbon / Q000378:metabolism; D017753:Ecosystem; D019015:Geologic Sediments / Q000821:virology; D052836:Heterotrophic Processes; D009792:Oceans and Seas; D059748:Proteolysis; D014780:Viruses / Q000378:metabolism*
chemical_list: D002244:Carbon
keywords: deep-sea ecosystems; ecosystem functioning; virus–prokaryote interactions
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