Department of Microbiology, Max Planck Institute for Marine Microbiology, Bremen, Germany.
ISME J. 2010 Feb;4(2):159-70. doi: 10.1038/ismej.2009.106. Epub 2009 Oct 15.
Microbial biogeographic patterns in the deep sea depend on the ability of microorganisms to disperse. One possible limitation to microbial dispersal may be the Walvis Ridge that separates the Antarctic Lower Circumpolar Deep Water from the North Atlantic Deep Water. We examined bacterial communities in three basins of the eastern South Atlantic Ocean to determine diversity and biogeography of bacterial communities in deep-sea surface sediments. The analysis of 16S ribosomal RNA (rRNA) gene clone libraries in each basin revealed a high diversity, representing 521 phylotypes with 98% identity in 1051 sequences. Phylotypes affiliated with Gammaproteobacteria, Deltaproteobacteria and Acidobacteria were present in all three basins. The distribution of these shared phylotypes seemed to be influenced neither by the Walvis Ridge nor by different deep water masses, suggesting a high dispersal capability, as also indicated by low distance-decay relationships. However, the total bacterial diversity showed significant differences between the basins, based on 16S rRNA gene sequences as well as on terminal restriction fragment length polymorphism fingerprints. Noticeably, both geographic distance and environmental heterogeneity influenced bacterial diversity at intermediate (10-3000 km) and large scales (>3000 km), indicating a complex interplay of local contemporary environmental effects and dispersal limitation.
深海中的微生物生物地理分布模式取决于微生物的扩散能力。微生物扩散的一个可能限制因素可能是沃尔维斯脊，它将南极低环极深海水与北大西洋深水分隔开。我们研究了东南大西洋三个盆地的海底细菌群落，以确定深海表层沉积物中细菌群落的多样性和生物地理学。对每个盆地的 16S 核糖体 RNA(rRNA)基因克隆文库的分析显示出高度的多样性，代表了 1051 个序列中 98%同一性的 521 个系统发育型。与γ变形菌门、δ变形菌门和酸杆菌门有关的系统发育型存在于这三个盆地中。这些共享系统发育型的分布似乎既不受沃尔维斯脊的影响，也不受不同的深水团的影响，这表明扩散能力很强，正如距离衰减关系所表明的那样。然而，基于 16S rRNA 基因序列和末端限制性片段长度多态性指纹图谱，三个盆地的总细菌多样性存在显著差异。值得注意的是，地理距离和环境异质性在中尺度（10-3000 公里）和大尺度（>3000 公里）上都对细菌多样性有影响，这表明局部当代环境效应和扩散限制之间存在复杂的相互作用。
