, Naudin at the Service d'Observation du Laboratoire Arago for oceanographic data and the French monitoring network SOMLIT for oceanographic coastal data. R.L.'s research was supported by a doctoral fellowship from the French Research and Education Ministry and by the Lavoisier postdoctoral fellowship from the French Foreign Office, J. J

M. K. , s stay in Banyuls was supported by a fellowship from the Université Pierre et Marie Curie -Paris 6. This research was also supported by GACR project 206/07/0241, GAAV project 1QS500200570 and the Inst. research concepts MSM6007-665808 and AV0Z50200510. We are grateful to D. L. Kirchman and his group in the College of Marine and Earth Studies for helpful comments on an earlier version of this manuscript

M. Allgaier, H. Uphoff, A. Felske, and I. Wagner-döbler, Aerobic anoxygenic photosynthesis in Roseobacter clade bacteria from diverse marine habitats, Appl Environ Microbiol, vol.69, pp.5051-5059, 2003.

O. Béjà, L. Aravind, E. V. Koonin, M. T. Suzuki, and . Others, Bacterial rhodopsin: evidence for a new type of phototrophy in the sea, Science, vol.289, pp.1902-1906, 2000.

D. F. Bird and J. Kalff, Protozoan grazing and size-activity structure of limnetic bacterial communities, Can J Fish Aquat Sci, vol.50, pp.370-380, 1993.

M. T. Cottrell, A. Mannino, and D. L. Kirchman, Aerobic anoxygenic phototrophic bacteria in the Mid-Atlantic Bight and the North Pacific Gyre, Appl Environ Microbiol, vol.72, pp.557-564, 2006.

J. M. Gasol, P. A. Del-giorgio, R. Massana, and C. M. Duarte, Active versus inactive bacteria: size-dependence in a coastal marine plankton community, Mar Ecol Prog Ser, vol.128, pp.91-97, 1995.

J. F. Ghiglione, G. Mevel, M. Pujo-pay, L. Mousseau, P. Lebaron et al., Diel and seasonal variations in abundance, activity and community structure of particleattached and free-living bacteria in NW Mediterranean Sea, Microb Ecol, vol.54, pp.217-231, 2007.

R. Goericke, Bacteriochlorophyll a in the ocean: Is anoxygenic bacterial photosynthesis important?, Limnol Oceanogr, vol.47, pp.290-295, 2002.

H. P. Grossart, K. W. Tang, T. Kiøboe, and H. Ploug, Comparison of cell-specific activity between free-living and attached bacteria using isolates and natural assemblages, FEMS Microbiol Lett, vol.266, pp.194-200, 2007.

N. Jiao, Y. Zhang, Y. Zeng, N. Hong, R. Liu et al., Distinct distribution pattern of abundance and diversity of aerobic anoxygenic phototrophic bacteria in the global ocean, Environ Microbiol, vol.9, pp.3091-3099, 2007.

M. Koblí=ek, J. Ston-egiert, S. Sagan, and Z. S. Kolber, Diel changes in bacteriochlorophyll a concentration suggest rapid bacterioplankton cycling in the Baltic Sea, FEMS Microbiol Ecol, vol.51, pp.353-361, 2005.

M. Koblí=ek, M. Ma$ín, J. Ras, A. J. Poulton, and P. , Rapid growth rates of aerobic anoxygenic phototrophs in the ocean, Environ Microbiol, vol.9, pp.2401-2406, 2007.

Z. S. Kolber, C. L. Van-dover, R. A. Niederman, and P. G. Falkowski, Bacterial photosynthesis in surface waters of the open ocean, Nature, vol.407, pp.177-179, 2000.

Z. S. Kolber, F. G. Plumley, A. S. Lang, J. T. Beatty, and . Others, Contribution of aerobic photoheterotrophic bacteria to the carbon cycle in the ocean, Science, vol.292, pp.2492-2495, 2001.

R. Lami, M. T. Cottrell, J. Ras, O. Ulloa, I. Obernosterer et al., High abundances of aerobic anoxygenic photosynthetic bacteria in the South Pacific Ocean, Appl Environ Microbiol, vol.73, pp.4198-4205, 2007.

M. Ma$ín, A. Zdun, J. Sto?-egiert, M. Nausch, M. Labrenz et al., Seasonal changes and diversity of aerobic anoxygenic phototrophs in the Baltic Sea, Aquat Microb Ecol, vol.45, pp.247-254, 2006.

M. Ma$ín, J. Nedoma, L. Pechar, and M. Koblí=ek, Distribution of aerobic anoxygenic phototrophs in temperate freshwater systems, Environ Microbiol, vol.10, pp.1988-1996, 2008.

J. Ras, H. Claustre, and J. Uitz, Spatial variability of phytoplankton pigment distributions in the subtropical South Pacific Ocean: comparison between in situ and predicted data, Biogeosciences, vol.5, pp.353-369, 2008.
URL : https://hal.archives-ouvertes.fr/hal-00330270

I. Salka, V. Moulisová, M. Koblí=ek, G. Jost, K. Jürgens et al., Abundance, depth distribution, and composition of aerobic bacteriochlorophyll a-producing bacteria in four basins of the central Baltic Sea, Appl Environ Microbiol, vol.74, pp.4398-4404, 2008.

M. S. Schwalbach and J. A. Fuhrman, Wide-ranging abundances of aerobic anoxygenic phototrophic bacteria in the world ocean revealed by epifluorescence microscopy and quantitative PCR, Limnol Oceanogr, vol.50, pp.620-628, 2005.

M. E. Sieracki, I. C. Gilg, E. C. Thier, N. J. Poulton, and R. Goericke, Distribution of planktonic aerobic anoxygenic photoheterotrophic bacteria in the Northwest Atlantic, Limnol Oceanogr, vol.51, pp.38-46, 2006.

M. Simon, H. P. Grossart, B. Schweitzer, and H. Ploug, Microbial ecology of organic aggregates in aquatic ecosystems, Aquat Microb Ecol, vol.28, pp.175-211, 2002.

L. A. Waidner and D. L. Kirchman, Aerobic anoxygenic phototrophic bacteria attached to particles in turbid waters of the Delaware and Chesapeake estuaries, Appl Environ Microbiol, vol.73, pp.3936-3944, 2007.

V. V. Yurkov and J. T. Beatty, Aerobic anoxygenic phototrophic bacteria, Microbiol Mol Biol Rev, vol.62, pp.695-724, 1998.

N. Yutin, M. T. Suzuki, H. Teeling, M. Weber, J. C. Venter et al., Assessing diversity and biogeography of aerobic anoxygenic phototrophic bacteria in surface waters of the Atlantic and Pacific Oceans using the Global Ocean Sampling expedition metagenomes, Environ Microbiol, vol.9, pp.1464-1475, 2007.

M. V. Zubkov and G. A. Tarran, Amino acid uptake of Prochlorococcus spp. in surface waters across the South Atlantic Subtropical Front, Aquat Microb Ecol, vol.40, pp.241-249, 2005.