Author Manuscript 1,* Solange Duhamel, 2 France Van Wambeke, 2 Dominique Lefevre, 2,3,4 Mar Benavides, 2,3 Sophie Bonnet 1 Lamont Doherty Earth Observatory, Columbia University, Palisades, NY 10964, USA 2 Aix Marseille Université, CNRS/INSU, Université de Toulon, IRD, Mediterranean Institute of Oceanography (MIO) UM 110, 13288, Marseille, France 3 Aix Marseille Université, CNRS/INSU, Université de Toulon, IRD, Mediterranean Institute of Oceanography (MIO) UM 110, 98848, Noumea, New Caledonia 4 Now at: Marine Biological Section, Department of Biology, University of Copenhagen, Strandpromenaden 5, 3000 Helsingør, Denmark * S Duhamel, Lamont@Doherty Earth Observatory of Columbia University, 61 Route 9W, Palisades, NY 10964@8000, USA E@mail: sduhamel@ldeo.columbia.edu; Phone: 845@365@8774; Fax: 845@365@8150 Mixotrophy in natural marine cyanobacteria Marine unicellular cyanobacteria of the genus and are major contributors to primary production and carbon (C) export in the open ocean. These picocyanobacteria are considered to be photoautotrophic, but Page 1 of 42 This is the author manuscript accepted for publication and has undergone full peer review but has not been through the copyediting, typesetting, pagination and proofreading process, which may lead to differences between this version and the Version of record. Please cite this article as doi:10.1111/ 1462-2920.14111. This article is protected by copyright. All rights reserved.