Department of Marine Biology, University of Vienna, Vienna, Austria.
PLoS One. 2010 Aug 10;5(8):e12321. doi: 10.1371/journal.pone.0012321.
We studied the meiofauna community at deep-sea hydrothermal vents along a gradient of vent fluid emissions in the axial summit trought (AST) of the East Pacific Rise 9°50'N region. The gradient ranged from extreme high temperatures, high sulfide concentrations, and low pH at sulfide chimneys to ambient deep-sea water conditions on bare basalt. We explore meiofauna diversity and abundance, and discuss its possible underlying ecological and evolutionary processes.
METHODOLOGY/PRINCIPAL FINDINGS: After sampling in five physico-chemically different habitats, the meiofauna was sorted, counted and classified. Abundances were low at all sites. A total of 52 species were identified at vent habitats. The vent community was dominated by hard substrate generalists that also lived on bare basalt at ambient deep-sea temperature in the axial summit trough (AST generalists). Some vent species were restricted to a specific vent habitat (vent specialists), but others occurred over a wide range of physico-chemical conditions (vent generalists). Additionally, 35 species were only found on cold bare basalt (basalt specialists). At vent sites, species richness and diversity clearly increased with decreasing influence of vent fluid emissions from extreme flow sulfide chimney (no fauna), high flow pompei worm (S: 4-7, H'(loge): 0.11-0.45), vigorous flow tubeworm (S: 8-23; H'(loge): 0.44-2.00) to low flow mussel habitats (S: 28-31; H'(loge): 2.34-2.60).
CONCLUSIONS/SIGNIFICANCE: Our data suggest that with increasing temperature and toxic hydrogen sulfide concentrations and increasing amplitude of variation of these factors, fewer species are able to cope with these extreme conditions. This results in less diverse communities in more extreme habitats. The finding of many species being present at sites with and without vent fluid emissions points to a non endemic deep-sea hydrothermal vent meiofaunal community. This is in contrast to a mostly endemic macrofauna but similar to what is known for meiofauna from shallow-water vents.
我们研究了东太平洋隆起 9°50'N 区域轴向山顶槽（AST）中沿热液喷口流体排放梯度的深海后生动物群落。该梯度范围从极端高温、高硫化物浓度和低 pH 值的硫化物烟囱到裸露玄武岩上的环境深海条件。我们探索了后生动物的多样性和丰度，并讨论了其可能的潜在生态和进化过程。
方法/主要发现：在五个物理化学条件不同的栖息地进行采样后，对后生动物进行了分类、计数和分类。所有地点的丰度都很低。在喷口栖息地共鉴定出 52 种物种。喷口群落以硬底基质广食性动物为主，这些动物在轴向山顶槽（AST 广食性动物）的环境深海温度下也生活在裸露的玄武岩上。一些喷口物种局限于特定的喷口栖息地（喷口专性种），但其他物种则在广泛的物理化学条件下存在（喷口广食性种）。此外，还有 35 种物种仅在寒冷的裸露玄武岩上发现（玄武岩专性种）。在喷口地点，物种丰富度和多样性随着喷口流体排放的影响减小而明显增加，从极端流动硫化物烟囱（无动物群）、高流动庞贝虫（S：4-7，H'（loge）：0.11-0.45）、活跃流动管虫（S：8-23；H'（loge）：0.44-2.00）到低流动贻贝栖息地（S：28-31；H'（loge）：2.34-2.60）。
结论/意义：我们的数据表明，随着温度和有毒硫化氢浓度的升高以及这些因素变化幅度的增大，能够应对这些极端条件的物种越来越少。这导致在更极端的栖息地中，群落的多样性降低。在有和没有喷口流体排放的地点都存在许多物种的发现表明，深海热液喷口后生动物群落并非特有。这与主要是特有种的大型动物群形成鲜明对比，但与浅水喷口的后生动物群相似。
