Open AccessEcology of aerobic anoxygenic phototrophic bacteria along an oligotrophic gradient in the Mediterranean Sea
Author(s) -
Dominique Lamy,
Christian Jeanthon,
Matthew T. Cottrell,
David L. Kirchman,
F. Van Wambeke,
J. Ras,
O. Dahan,
Mireille PujoPay,
L. Oriol,
L. Bariat,
Philippe Catala,
Véronique Cornet-Barthaux,
Philippe Lebaron
Publication year - 2011
Publication title -
biogeosciences discussions
Language(s) - English
Resource type - Journals
ISSN - 1810-6285
DOI - 10.5194/bgd-8-323-2011
Subject(s) - anoxygenic photosynthesis , phototroph , nutrient , ecology , dissolved organic carbon , mediterranean sea , oceanography , trophic level , environmental science , environmental chemistry , biology , mediterranean climate , botany , photosynthesis , chemistry , geology
Aerobic anoxygenic phototrophic (AAP) bacteria are photoheterotrophic prokaryotes able to use both light and organic substrates for energy production. They are widely distributed in coastal and oceanic environments and may contribute significantly to the carbon cycle in the upper ocean. To better understand questions regarding links between the ecology of these photoheterotrophic bacteria and the trophic status of water masses, we examined their horizontal and vertical distribution and the effects of nutrient additions on their growth along an oligotrophic gradient in the Mediterranean Sea. Concentrations of bacteriochlorophyll-a (BChl-a) and AAP bacterial abundance decreased from the western to the eastern basins of the Mediterranean Sea and were linked with concentrations of chlorophyll-a, nutrient and dissolved organic carbon. Inorganic nutrient and glucose additions to surface seawater samples along the oligotrophic gradient revealed that AAP bacteria were nitrogen- and carbon-limited in the ultra-oligotrophic eastern basin. The intensity of the AAP bacterial growth response generally differed from that of the total bacterial growth response. BChl-a quota of AAP bacterial communities was significantly higher in the eastern basin than in the western basin, suggesting that reliance on phototrophy varied along the oligotrophic gradient and that nutrient and/or carbon limitation favors BChl-a synthesis