The Great Meteor Seamount (Northeast Atlantic): stepping stone or trapping stone? Quantitative investigations of the distribution, diversity, and origin of the Harpacticoida (Crustacea, Copepoda) of the seamount summit

在一个旨在调查海山对海洋小型底栖生物扩散的可能作用并为澄清所谓小型底栖生物悖论作出贡献的全面项目框架内，本申请项目侧重于对大流星海山高原的硬足类（甲壳纲、桡足类）进行定量分类和多变量群落分析。以前的调查是以定性取样材料为基础的，只是为了处理以下问题：大湄公河次区域在小型底栖生物扩散方面可能发挥的垫脚石作用，或者该海山在水文和地理上的孤立是否反而导致了独特的硬水蚤组合的发展。据几位作者说，后一种假设似乎更有道理。然而，由于底层取样材料的意义有限，特别是因为取样使用的是不同的齿轮，2010年“海神号”考察船前往大湄公河次区域的P397研究巡航首次实现了对整个区域的小型底栖生物进行全面取样。在高原上对21个网格状定位点进行了定量采样。对取样材料的评价应提供大湄公河次区域高原上硬鞭虾分布的有意义的数据。此外，科学上已知的和未知的物种之间的关系将被估计;这可能允许识别，如果一个连续的移民物种从其他地区确实发生，或者如果harpacticoid到达GMS高原可能是相当单一和偶然的。对后者的指示应该是科学上未知的物种的比例相对较高，同时表明明显的地方性。此外，相对较高比例的密切相关但不同的物种可能支持以下假设：GMS上存在一个孤立和独特的猛水蚤动物群，它们是通过意外抵达物种的辐射进化而来的;由于没有潜在竞争者的频繁迁移，高原物种即使在某些地区也能实现新的生态位。（货架，沿岸的），因为竞争压力太大，它们没有任何机会。除动物区系比较外，还旨在将获得的数据与其他海山（塞德洛、塞纳）和马德拉岛的数据进行比较。应描述新物种，并使其可用于进一步的生物学研究。预计，这里应用的项目可能会从根本上有助于我们的知识，在东北大西洋的Harpacticoida的扩散。

In the frame of a thorough project aiming to investigate the possible role of seamounts for the dispersal of marine meiobenthos, and to contribute towards clearing the so-called meiofauna paradox, the here applied project focuses on quantitative taxonomic and multivariate community analyses of the Harpacticoida (Crustacea, Copepoda) from the plateau of the Great Meteor Seamount (GMS). Previous investigations were based on qualitative sampling material only to treat questions as to a possible role as stepping stone of GMS for the dispersal of meiofauna, or whether the hydrographic and geographic isolation of that seamount instead lead to the development of unique harpacticoid assemblages. According to several authors, the latter assumption seems to be more plausible. However, as the underlying sampling material has a limited significance only, in particular because it was sampled using different gears, research cruise P397 of RV POSEIDON to the GMS in 2010 enabled for the first time an area-wide and comprehensive sampling of meiofauna. Twenty-one grid-like positioned locations were sampled quantitatively on the plateau. Evaluation of the sampling material shall provide meaningful data of the distribution of Harpacticoida on the GMS plateau. Moreover, the relation between scientifically known and unknown species will be estimated; this may allow recognizing if a continuous immigration of species from other regions does occur, or if harpacticoid arrivals on the GMS plateau may be rather singular and accidental. Indication for the latter should be a comparatively high portion of scientifically unknown species, pointing at the same time to a pronounced endemism. Also a relatively high part of closely related but distinct species might support the assumption of an isolated and unique harpacticoid fauna on GMS that evolved via radiation of accidentally arrived species; as there is no frequent immigration of potential competitors, plateau species are able to realize new ecological niches even in areas (shelves, littoral) where they would not have any chance because of too high pressure of competition.Furthermore the hypothesis of a harpacticoid plateau fauna as mainly descending from deep-sea relatives (emergence) shall be proved; former studies found corresponding indications, while on other seamounts a clear dominance of shallow-water species was detected.Beyond a faunistisc comparison it is aimed to compare the obtained data with those from other seamounts (Sedlo, Seine) and ith the island of Madeira. New species shall be described and made therewith accessible for further biological studies. It is expected that the here applied project may contribute fundamentally to our knowledge of the dispersal of Harpacticoida in the northeast Atlantic.