Open AccessSummer distribution and diversity of aerobic anoxygenic phototrophic bacteria in the Mediterranean Sea in relation to environmental variables
Author(s) -
Lehours AnneCatherine,
Cottrell Matthew T.,
Dahan Océane,
Kirchman David L.,
Jeanthon Christian
Publication year - 2010
Publication title -
fems microbiology ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.377
H-Index - 155
eISSN - 1574-6941
pISSN - 0168-6496
DOI - 10.1111/j.1574-6941.2010.00954.x
Subject(s) - biology , anoxygenic photosynthesis , gammaproteobacteria , phototroph , ecology , mediterranean sea , bacterioplankton , population , chemocline , mediterranean climate , botany , water column , bacteria , nutrient , phytoplankton , photosynthesis , genetics , 16s ribosomal rna , demography , sociology
Aerobic anoxygenic phototrophic bacteria (AAP) represent an important fraction of bacterioplankton assemblages in various oceanic regimes. Although their abundance and distribution have been explored recently in diverse oceanic regions, the environmental factors controlling the population structure and diversity of these photoheterotrophic bacteria remain poorly understood. Here, we investigate the horizontal and vertical distributions and the genetic diversity of AAP populations collected in late summer throughout the Mediterranean Sea using pufM ‐temporal temperature gel gradient electrophoresis (TTGE) and clone library analyses. The TTGE profiles and clone libraries analyzed using multivariate statistical methods demonstrated a horizontal and vertical zonation of AAP assemblages. Physicochemical parameters such as pH, inorganic nitrogen compounds, photosynthetically active radiation, total organic carbon and to a lesser extent particulate organic nitrogen and phosphorus, and biogenic activities (e.g. bacterial production, cell densities), acted in synergy to explain the population changes with depth. About half of the pufM sequences were <94% identical to known sequences. The AAP populations were predominantly (∼80%) composed of Gammaproteobacteria , unlike most previously explored marine systems. Our results suggest that genetically distinct ecotypes inhabiting different niches may exist in natural AAP populations of the Mediterranean Sea whose genetic diversity is typical of oligotrophic environments.