RAPID: Larval Abundance, Behavior and Dispersal at Deep-sea Hydrothermal Vents in the Southern Mariana Trough

摘要：自从30多年前深海热液喷口被发现以来，科学家们一直被这个问题所困扰：这些喷口是如何被殖民的，更具体地说，动物种群是如何在这些非常分散的、往往是短暂的栖息地建立和维持的。对于无根的或成年后流动性有限的动物来说，在生命周期的早期，作为浮游生物的幼虫在水柱中扩散到这些栖息地。由于深海幼虫取样困难，包括丰度低（稀浓度），我们很少定量估计幼虫在热液喷口之间的扩散或幼虫供应。我们对喷口幼虫的行为也知之甚少。pi将使用大容量的浮游生物泵在南马里亚纳海槽的通风口附近收集幼虫，以合作的方式量化这一研究较少的地区的幼虫丰度、行为和扩散。该合作结合了PI在深海喷口之间幼虫的收集和形态鉴定以及量化和建模传播方面的优势，以及日本合作伙伴在热液喷口动物幼虫饲养，幼虫分子遗传学鉴定和喷口动物种群遗传学方面的优势。学术价值：南马里亚纳海槽是一个非常有趣的研究喷口特有动物群扩散的地区，因为弧后扩张中心的喷口靠近马里亚纳弧上的喷口。这两种构造环境创造了不同的生境条件，支持了不同物种组成的喷口群落。pi将访问的火山口位于弧后扩张中心的轴线上和离轴线上，距离弧上的火山口近25公里，但距离弧后其他已知的火山口以南600公里。除了将为这个世界山脊系统中很少被研究的地区获得关于幼虫丰度、多样性、行为和扩散的新信息外，该项目还与美国山脊2000计划的整合和综合目标直接相关。PI的实验室小组在Ridge 2000东太平洋隆起（EPR）综合研究基地（ISS）进行了之前的工作。他们将直接比较EPR ISS的幼虫丰度和多样性，与海洋扩散中心的全球“棒球缝”非常不同的环境。由于对使用大容量泵的幼虫缺乏取样努力，没有其他这样的比较是可能的。此外，他们还提出了第一次用活的喷口幼虫进行实验（据我们所知，除了1atm的长尾巨翅虫），以估计游泳和下沉的速度，这对增加幼虫扩散模型的行为信息很重要。更广泛的影响：该项目涉及互惠培训和文化交流——项目负责人将向日本的项目负责人学习现场和实验室研究技术，并向美国的项目负责人学习。该项目也将有利于初级研究员（Beaulieu）的职业发展。这项拟议中的活动扩大了美国和日本女科学家对航海和海洋学研究的参与。pi将在国际InterRidge项目办公室发布的网络日志中广播巡航活动，他们预计至少会出现三份科学出版物。新的物种将被添加到喷口幼虫的在线照片识别指南中，并列入第二版的印刷指南。

RAPID: Larval abundance, behavior, and dispersal at deep-sea hydrothermal vents in the southern Mariana TroughSummary: Since the discovery of deep-sea hydrothermal vents over thirty years ago, scientists have been perplexed by the question: How are these vent sites colonized and, more specifically, How are the faunal populations established and maintained at these very discrete and often ephemeral habitats. For animals that are sessile or have limited mobility as adults, dispersal to these habitats occurs early in the life cycle, as planktonic larvae in the water column. Due to the difficulties in sampling deep-sea larvae, including low abundances (dilute concentrations), we have very few quantitative estimates of larval dispersal between or larval supply to hydrothermal vents. We also have little to no knowledge of the behavior of vent larvae. The PIs will use large-volume plankton pumps to collect larvae near vents in the southern Mariana Trough in a collaborative effort to quantify larval abundance, behavior, and dispersal in this little-studied region. The collaboration combines the PI's strengths in the collection and morphological identification of larvae and quantifying and modeling dispersal between deep-sea vents, and those of Japanese partners in rearing larvae of hydrothermal vent fauna, molecular genetic identification of larvae, and population genetics of vent fauna.Intellectual merit: The southern Mariana Trough is a very interesting region in which to study dispersal of vent-endemic fauna, due to the proximity of vents in the back-arc spreading center to vents along the Mariana Arc. These two tectonic settings create different habitat conditions and support vent communities with different species composition. Vent sites the PIs will visit, in the axis and just off-axis of the back-arc spreading center are as close as 25 km to vents on the arc, yet 600 km south of the other known vents in the back-arc. In addition to the new information on larval abundance, diversity, behavior, and dispersal that will be gained for this little-studied region of the world's ridge system, this project has direct relevance to the integration and synthesis goals of the U.S. Ridge 2000 Program. The PI's lab group has conducted previous work at the Ridge 2000 East Pacific Rise (EPR) Integrated Studies Site (ISS). They will be making a direct comparison of the larval abundance and diversity at the EPR ISS to this very different setting along the global 'baseball seam' of oceanic spreading centers. No other such comparison has been possible due to the lack of sampling effort for larvae with large-volume pumps. Also, they are proposing the first experiments with live vent larvae (to the best of our knowledge - with the exception of brachyuran megalopae at 1 atm) to estimate swimming and sinking rates that are important for adding behavioral information to models of larval dispersal.Broader Impacts: The project involves reciprocal training and cultural exchange - the PIs will learn field and laboratory research techniques from the Japanese PIs, and they will learn from the U.S. PIs. The project will also benefit the career development of a junior researcher (Beaulieu). The proposed activity broadens the participation of both U.S. and Japanese women scientists in sea-going, oceanographic research. The PIs will broadcast the cruise activities in a web log posted by the international InterRidge Program Office, and they anticipate at least three scientific publications will emerge. New species will be added to the online photographic identification guide for vent larvae and included in the second edition of the printed guide.