In situ imaging reveals the biomass of giant protists in the global ocean

Type : ACL
Nature : Production scientifique
Au bénéfice du Laboratoire : Oui
Statut de publication : Publié
Année de publication : 2016
Auteurs (10) : BIARD Tristan STEMMANN Lars PICHERAL Marc MAYOT Nicolas VANDROMME Pieter HAUSS H GORSKY Gabriel GUIDI Lionel KIKO Rainer NOT Fabrice
Revue scientifique : Nature
Volume : 532
Fascicule : 7600
Pages : 504-507
DOI : 10.1038/nature17652
URL : http://dx.doi.org/10.1038/nature17652
Abstract : Planktonic organisms play crucial roles in oceanic food webs and global biogeochemical cycles1, 2. Most of our knowledge about the ecological impact of large zooplankton stems from research on abundant and robust crustaceans, and in particular copepods3, 4. A number of the other organisms that comprise planktonic communities are fragile, and therefore hard to sample and quantify, meaning that their abundances and effects on oceanic ecosystems are poorly understood. Here, using data from a worldwide in situ imaging survey of plankton larger than 600 μm, we show that a substantial part of the biomass of this size fraction consists of giant protists belonging to the Rhizaria, a super-group of mostly fragile unicellular marine organisms that includes the taxa Phaeodaria and Radiolaria (for example, orders Collodaria and Acantharia). Globally, we estimate that rhizarians in the top 200 m of world oceans represent a standing stock of 0.089 Pg carbon, equivalent to 5.2% of the total oceanic biota carbon reservoir5. In the vast oligotrophic intertropical open oceans, rhizarian biomass is estimated to be equivalent to that of all other mesozooplankton (plankton in the size range 0.2–20 mm). The photosymbiotic association of many rhizarians with microalgae may be an important factor in explaining their distribution. The previously overlooked importance of these giant protists across the widest ecosystem on the planet6 changes our understanding of marine planktonic ecosystems.
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Citation :
Biard T, Stemmann L, Picheral M, Mayot N, Vandromme P, Hauss H, Gorsky G, Guidi L, Kiko R, Not F (2016) In situ imaging reveals the biomass of giant protists in the global ocean. Nature 532: 504-507 | doi: 10.1038/nature17652