Biogeography and ecology of the first known deep-sea hydrothermal vent site on the ultraslow-spreading Southwest Indian Ridge

这项提议是对NERC研究巡航的一次短暂延长，以获得全球深海生命拼图中缺失的一块，从而促进我们对地球上最大生态系统中生物多样性模式的理解。计划是参观西南印度洋海脊(SWIR)上的一个地点，中国的一艘科考船最近首次在那里观察到深海喷口，但没有进行采样。在2011/12年度，NERC的一艘邮轮将与英国的遥控潜水器(ROV)ISIS一起访问仅110公里外的印度洋海底山脉。因此，这项提议是随船访问附近的喷口地点，并在这个大洋中脊的深海喷口进行有史以来第一次ROV潜水。深海喷口支撑着繁茂的海洋生物群落，最终是由海底涌出的化学物质滋养的。在过去30年里，对喷口的调查发现了数百种新的动物物种，彻底改变了生态系统如何获得能量的想法，甚至为生命的起源提供了线索。但我们还没有弄清楚是什么控制着这些海岛般的海底极端环境中物种的全球分布。到目前为止，30年的调查已经揭示了六个省的喷口动物生活，在不同地区的喷口发现了不同的物种。这些省份类似于陆地大陆--例如生活在非洲的狮子和生活在印度的老虎--但与陆地上的这种生活模式不同，这些省份的起源和维持尚不清楚。深海喷口散布在大洋中脊，这是一条65000公里长的海底火山链。大洋中脊的一些部分比其他部分火山活动更活跃。SWIR是一个超低扩张的山脊，那里的火山活动较少，地壳板块的分离速度比其他地区要慢。深海喷口沿大洋中脊的间距随着火山活动而减小。在快速扩张的海脊，例如东太平洋，喷口之间的距离不到几十公里。在活动较少的缓慢扩张的海脊上，如中大西洋海脊，喷口相隔数百公里。这种差异可能会影响在喷口发现的物种，因为一些物种的幼虫比其他物种的幼虫更有能力在喷口之间分散很长距离。但这一想法还没有得到彻底的检验，生活在超低扩张海脊上的物种在很大程度上是未知的，尽管这种海脊按比例形成了全球大洋中脊系统中最长的长度。因此，国际海洋生物普查将SWIR确定为优先目标，以了解是什么塑造了深海喷口的全球生命模式。由于我们对深海物种扩散的总体了解大多来自于对这些系统的研究，这将促进我们对深海生物多样性模式的理解。在这个超低扩张海脊的深海喷口进行第一次ROV潜水，将决定它的动物群是否与其他海脊不同。来自中国考察队的海底图像表明，一些物种可能与NERC财团最近在南大洋喷口发现的物种相似。因此，ROV收集的样本和数据将检验南半球存在一个新的喷口生物学区域的假设。该项目还将为海洋生物技术部门收集新生物的样本，并通过外展活动与公众分享其发现。考虑到在印度洋进行研究巡航的成本，延长现有邮轮访问SWIR上第一个已知深海喷口的独特机会对NERC的科学具有特殊的价值。通过回答深海生态学中的一个关键问题，这项建议还解决了NERC在知识前沿提供世界级研究的目标。

This proposal is for a short extension to a NERC research cruise to obtain a missing piece of a global jigsaw puzzle of deep-sea life, thereby advancing our understanding of the patterns of biodiversity in the Earth's largest ecosystem. The proposal is to visit a site on the Southwest Indian Ridge (SWIR) where deep-sea vents were recently observed for the first time, but not sampled, by a Chinese research cruise. In 2011/12, a NERC cruise will be visiting undersea mountains in the Indian Ocean just 110 km away with Isis, the UK's remotely-operated vehicle (ROV). This proposal is therefore to visit the nearby vent site with the ship, and undertake the first ever ROV dives at a deep-sea vent on this mid-ocean ridge. Deep-sea vents support lush colonies of marine life, ultimately nourished by chemicals gushing from the seafloor. Investigations of vents over the past three decades have found hundreds of new animal species, revolutionised ideas about how ecosystems can be supplied with energy, and even provided clues to the origins of life. But we have yet to understand what controls the global distribution of species in these island-like extreme environments on the ocean floor. Thirty years of investigations have so far revealed six provinces of animal life at vents, where different species are found at vents in different regions. These provinces are akin to terrestrial continents - e.g. lions living in Africa and tigers in India - but unlike such patterns of life on land, the origin and maintenance of these provinces are not yet understood. Deep-sea vents are dotted along the mid-ocean ridge, a 65000 km chain of undersea volcanoes. Some sections of the mid-ocean ridge are more volcanically active than others. The SWIR is an ultraslow-spreading ridge, where there is less volcanic activity and the plates of the Earth's crust are moving apart more slowly than in other regions. The spacing of deep-sea vents along the mid-ocean ridge decreases with its volcanic activity. At fast-spreading ridges, such as in the Eastern Pacific, vents are less than tens of kilometres apart. On less active slow-spreading ridges, such as the Mid-Atlantic Ridge, vents are hundreds of kilometres apart. This difference may influence which species are found at vents, as the larvae of some species are more capable than others of dispersing long distances between vents. But this idea has yet to be thoroughly tested and the species that live on ultraslow-spreading ridges are largely unknown, despite such ridges forming proportionally the greatest length of the global mid-ocean ridge system. The international Census of Marine Life has therefore identified the SWIR as a priority target to understand what shapes global patterns of life at deep-sea vents. As much of what we know about the dispersal of deep-sea species in general comes from studying these systems, this will advance our understanding of patterns of biodiversity in the deep ocean. Undertaking the first ROV dives at a deep-sea vent on this ultraslow-spreading ridge will determine whether its fauna differ from other ridges. Seafloor images from the Chinese expedition suggest that some species may be similar to those recently discovered at vents in the Southern Ocean by a NERC Consortium. The samples and data collected by the ROV will therefore test the hypothesis that there is a new province of vent biology in the southern hemisphere. The project will also collect samples of novel organisms for the marine biotechnology sector, and share its discoveries with the public through outreach activities. Given the costs of mounting a research cruise in the Indian Ocean, this unique opportunity to extend an existing cruise to visit the first-known deep-sea vent on the SWIR represents exceptional value for NERC science. By answering a key question in deep-sea ecology, this proposal also addresses NERC's goal of delivering world-class research at the frontiers of knowledge.