Schattenhofer Martha, Fuchs Bernhard M, Amann Rudolf, Zubkov Mikhail V, Tarran Glen A, Pernthaler Jakob
Max Planck Institute for Marine Microbiology, D-28359 Bremen, Germany.
Environ Microbiol. 2009 Aug;11(8):2078-93. doi: 10.1111/j.1462-2920.2009.01929.x. Epub 2009 Apr 30.
Members of the prokaryotic picoplankton are the main drivers of the biogeochemical cycles over large areas of the world's oceans. In order to ascertain changes in picoplankton composition in the euphotic and twilight zones at an ocean basin scale we determined the distribution of 11 marine bacterial and archaeal phyla in three different water layers along a transect across the Atlantic Ocean from South Africa (32.9 degrees S) to the UK (46.4 degrees N) during boreal spring. Depth profiles down to 500 m at 65 stations were analysed by catalysed reporter deposition fluorescence in situ hybridization (CARD-FISH) and automated epifluorescence microscopy. There was no obvious overall difference in microbial community composition between the surface water layer and the deep chlorophyll maximum (DCM) layer. There were, however, significant differences between the two photic water layers and the mesopelagic zone. SAR11 (35 +/- 9%) and Prochlorococcus (12 +/- 8%) together dominated the surface waters, whereas SAR11 and Crenarchaeota of the marine group I formed equal proportions of the picoplankton community below the DCM (both approximately 15%). However, due to their small cell sizes Crenarchaeota contributed distinctly less to total microbial biomass than SAR11 in this mesopelagic water layer. Bacteria from the uncultured Chloroflexi-related clade SAR202 occurred preferentially below the DCM (4-6%). Distinct latitudinal distribution patterns were found both in the photic zone and in the mesopelagic waters: in the photic zone, SAR11 was more abundant in the Northern Atlantic Ocean (up to 45%) than in the Southern Atlantic gyre (approximately 25%), the biomass of Prochlorococcus peaked in the tropical Atlantic Ocean, and Bacteroidetes and Gammaproteobacteria bloomed in the nutrient-rich northern temperate waters and in the Benguela upwelling. In mesopelagic waters, higher proportions of SAR202 were present in both central gyre regions, whereas Crenarchaeota were clearly more abundant in the upwelling regions and in higher latitudes. Other phylogenetic groups such as the Planctomycetes, marine group II Euryarchaeota and the uncultured clades SAR406, SAR324 and SAR86 rarely exceeded more than 5% of relative abundance.
原核生物微微型浮游生物是世界大洋大片区域生物地球化学循环的主要驱动者。为了确定一个大洋盆地尺度上真光层和弱光层中微微型浮游生物组成的变化，我们在北半球春季期间，沿着从南非（南纬32.9度）到英国（北纬46.4度）横跨大西洋的断面，测定了三个不同水层中11个海洋细菌和古菌门的分布。通过催化报告沉积荧光原位杂交（CARD-FISH）和自动落射荧光显微镜，分析了65个站点深度达500米的深度剖面。表层水层和深层叶绿素最大值（DCM）层之间的微生物群落组成没有明显的总体差异。然而，两个光合水层和中层带之间存在显著差异。SAR11（35±9%）和原绿球藻（12±8%）共同主导了表层水，而海洋I群的SAR11和泉古菌在DCM以下的微微型浮游生物群落中占比相同（均约为15%）。然而，由于其细胞体积小，在这个中层带水层中，泉古菌对总微生物生物量的贡献明显低于SAR11。未培养的与绿弯菌相关的SAR202分支细菌优先出现在DCM以下（4 - 6%）。在光合带和中层带水域都发现了明显的纬度分布模式：在光合带，SAR11在北大西洋（高达45%）比在南大西洋环流（约25%）更丰富，原绿球藻的生物量在热带大西洋达到峰值，拟杆菌门和γ-变形菌在营养丰富的北温带水域和本格拉上升流中大量繁殖。在中层带水域，两个中央环流区域中SAR202的比例更高，而泉古菌在上升流区域和高纬度地区明显更为丰富。其他系统发育类群，如浮霉菌门、海洋II群广古菌以及未培养的SAR406、SAR324和SAR86分支，相对丰度很少超过5%。
