title: Major viral impact on the functioning of benthic deep-sea ecosystems.
abstract: Viruses are the most abundant biological organisms of the world's oceans. Viral infections are a substantial source of mortality in a range of organisms-including autotrophic and heterotrophic plankton-but their impact on the deep ocean and benthic biosphere is completely unknown. Here we report that viral production in deep-sea benthic ecosystems worldwide is extremely high, and that viral infections are responsible for the abatement of 80% of prokaryotic heterotrophic production. Virus-induced prokaryotic mortality increases with increasing water depth, and beneath a depth of 1,000 m nearly all of the prokaryotic heterotrophic production is transformed into organic detritus. The viral shunt, releasing on a global scale approximately 0.37-0.63 gigatonnes of carbon per year, is an essential source of labile organic detritus in the deep-sea ecosystems. This process sustains a high prokaryotic biomass and provides an important contribution to prokaryotic metabolism, allowing the system to cope with the severe organic resource limitation of deep-sea ecosystems. Our results indicate that viruses have an important role in global biogeochemical cycles, in deep-sea metabolism and the overall functioning of the largest ecosystem of our biosphere.
authors.affiliation: Department of Marine Science, Faculty of Science, Polytechnic University of Marche, Via Brecce Bianche, 60131 Ancona, Italy. r.danovaro@univpm.it
authors.forename: Roberto
authors.initials: R
authors.lastname: Danovaro
authors.forename: Antonio
authors.initials: A
authors.lastname: Dell'Anno
authors.forename: Cinzia
authors.initials: C
authors.lastname: Corinaldesi
authors.forename: Mirko
authors.initials: M
authors.lastname: Magagnini
authors.forename: Rachel
authors.initials: R
authors.lastname: Noble
authors.forename: Christian
authors.initials: C
authors.lastname: Tamburini
authors.forename: Markus
authors.initials: M
authors.lastname: Weinbauer