Ifremer, REM/EEP/LEP, F 29280 Plouzané, France.
Norwegian Institute for Water Research, Gaustadalleen 21, 0349 Oslo, Norway; REV Ocean, Oksenøyveien 10, 1366 Lysaker, Norway.
Mar Environ Res. 2021 Jun;168:105316. doi: 10.1016/j.marenvres.2021.105316. Epub 2021 Mar 31.
So far, the natural recovery of vent communities at large scales has only been evaluated at fast spreading centers, by monitoring faunal recolonisation after volcanic eruptions. However, at slow spreading ridges, opportunities to observe natural disturbances are rare, the overall hydrothermal system being more stable. In this study, we implemented a novel experimental approach by inducing a small-scale disturbance to assess the recovery potential of vent communities along the slow-spreading northern Mid-Atlantic Ridge (nMAR). We followed the recovery patterns of thirteen Bathymodiolus azoricus mussel assemblages colonising an active vent edifice at the Lucky Strike vent field, in relation to environmental conditions and assessed the role of biotic interactions in recolonisation dynamics. Within 2 years after the disturbance, almost all taxonomic richness had recovered, with the exception of a few low occurrence species. However, we observed only a partial recovery of faunal densities and a major change in faunal composition characterised by an increase in abundance of gastropod species, which are hypothesised to be the pioneer colonists of these habitats. Although not significant, our results suggest a potential role of mobile predators in early-colonisation stages. A model of post-disturbance succession for nMAR vent communities from habitat opening to climax assemblages is proposed, also highlighting numerous knowledge gaps. This type of experimental approach, combined with dispersal and connectivity analyses, will contribute to fully assess the resilience of active vent communities after a major disturbance, especially along slow spreading centers targeted for seafloor massive sulphide extraction.
到目前为止，大规模的喷口群落的自然恢复仅在快速扩张中心进行了评估，方法是监测火山喷发后动物群的重新定居。然而，在缓慢扩张的脊上，观察自然干扰的机会很少，整个热液系统更加稳定。在这项研究中，我们采用了一种新的实验方法，通过引入小规模干扰来评估缓慢扩张的北大西洋中脊北部（nMAR）喷口群落的恢复潜力。我们跟踪了 13 个 Bathymodiolus azoricus 贻贝群落在幸运罢工喷口场活跃喷口建筑上的殖民恢复模式，与环境条件有关，并评估了生物相互作用在重新定居动态中的作用。在干扰后 2 年内，几乎所有的分类丰富度都得到了恢复，除了少数低出现的物种。然而，我们只观察到了种群密度的部分恢复和种群组成的重大变化，特征是腹足动物物种的丰度增加，这些物种被假设是这些栖息地的先驱殖民者。尽管不显著，但我们的结果表明，移动捕食者在早期殖民阶段可能发挥作用。提出了一种从栖息地开放到高潮群落的 nMAR 喷口群落的干扰后演替模型，还突出了许多知识空白。这种实验方法与扩散和连通性分析相结合，将有助于充分评估主要干扰后活跃喷口群落的恢复力，特别是在针对海底块状硫化物开采的缓慢扩张中心。
