Lami Raphaël, Cottrell Matthew T, Ras Joséphine, Ulloa Osvaldo, Obernosterer Ingrid, Claustre Hervé, Kirchman David L, Lebaron Philippe
Observatoire Océanologique de Banyuls, Université Pierre et Marie Curie-Paris 6, UMR7621-INSU-CNRS, BP44, F-66650 Banyuls-sur-Mer, France.
Appl Environ Microbiol. 2007 Jul;73(13):4198-205. doi: 10.1128/AEM.02652-06. Epub 2007 May 11.
Little is known about the abundance, distribution, and ecology of aerobic anoxygenic phototrophic (AAP) bacteria, particularly in oligotrophic environments, which represent 60% of the ocean. We investigated the abundance of AAP bacteria across the South Pacific Ocean, including the center of the gyre, the most oligotrophic water body of the world ocean. AAP bacteria, Prochlorococcus, and total prokaryotic abundances, as well as bacteriochlorophyll a (BChl a) and divinyl-chlorophyll a concentrations, were measured at several depths in the photic zone along a gradient of oligotrophic conditions. The abundances of AAP bacteria and Prochlorococcus were high, together accounting for up to 58% of the total prokaryotic community. The abundance of AAP bacteria alone was up to 1.94 x 10(5) cells ml(-1) and as high as 24% of the overall community. These measurements were consistent with the high BChl a concentrations (up to 3.32 x 10(-3) microg liter(-1)) found at all stations. However, the BChl a content per AAP bacterial cell was low, suggesting that AAP bacteria are mostly heterotrophic organisms. Interestingly, the biovolume and therefore biomass of AAP bacteria was on average twofold higher than that of other prokaryotic cells. This study demonstrates that AAP bacteria can be abundant in various oligotrophic conditions, including the most oligotrophic regime of the world ocean, and can account for a large part of the bacterioplanktonic carbon stock.
对于需氧不产氧光合细菌（AAP细菌）的丰度、分布和生态，人们了解甚少，尤其是在占海洋面积60%的贫营养环境中。我们调查了南太平洋包括环流中心（世界海洋中最贫营养的水体）在内的AAP细菌丰度。沿着贫营养条件梯度，在光合层的几个深度测量了AAP细菌、原绿球藻和总原核生物丰度，以及细菌叶绿素a（BChl a）和二乙烯基叶绿素a浓度。AAP细菌和原绿球藻的丰度很高，二者合计占原核生物群落总数的比例高达58%。仅AAP细菌的丰度就高达1.94×10⁵个细胞/毫升，占整个群落的比例高达24%。这些测量结果与在所有站点发现的高BChl a浓度（高达3.32×10⁻³微克/升）一致。然而，每个AAP细菌细胞的BChl a含量较低，这表明AAP细菌大多是异养生物。有趣的是，AAP细菌的生物体积以及因此其生物量平均比其他原核细胞高两倍。这项研究表明，AAP细菌在各种贫营养条件下都可能大量存在，包括世界海洋中最贫营养的区域，并且可以占浮游细菌碳储量的很大一部分。
