Collaborative Research: dispersal depth and the transport of deep-sea, methane-seep larvae around a biogeographic barrier

自从40多年前在深海首次发现热液喷口和甲烷渗漏以来，科学家们一直在想，这些完全依赖于水下有毒化学物质的孤立群落是如何首先被生物殖民的，以及这些特殊动物的种群是如何交换和维持的。这些基本过程依赖于洋流运送婴儿(幼虫)，但由于幼虫是微小的，在浩瀚的海洋中被稀释，因此很难确定它们漂移到哪里以及如何漂移。该项目使用自动水下机器人从水柱的精确区域收集幼虫。还将使用底部的幼虫陷阱和幼虫壳的化学分析来确定幼虫游泳的深度。这些发现将为数学模型提供现实的估计，这些模型表明生物如何与洋流相互作用，以预测哪些甲烷渗漏将被来自不同深度的幼虫定居。为了养护和管理深海，需要对幼虫扩散有详细的了解。没有这些信息，我们无法知道海洋保护区的最佳位置，也无法促进受深海采矿、钻探或其他人类活动影响的社区的重建。该项目将为大学生提供海上实践培训，以学习在自然栖息地研究幼虫和胚胎所需的迅速消失的技能。还将通过为俄勒冈州、华盛顿州和北卡罗来纳州海岸的小型博物馆和水族馆制作的关于深海生物学和幼虫生态的新的互动展览，向所有年龄段的个人提供学习机会。可靠地估计集合种群之间的连通性在海洋养护生物学、生态学和系统地理学中越来越重要，但深海生物物理模型的生物学参数在很大程度上仍然无法获得。深海喷口和渗漏幼虫在适合化学合成的生境岛屿之间的活动已通过数值模拟从目前的模式中推断出来，但几乎所有此类模型都使用了对预测有重大影响的生物参数的未经检验的假设。该项目试图填补缺失的生物参数，同时开发更好的模型来预测生活在墨西哥湾和西大西洋边缘的甲烷渗漏动物的扩散模式。尽管在佛罗里达半岛两侧类似深度存在类似的渗漏，但西大西洋渗漏只支持墨西哥湾发现的物种的一部分。据推测，幼虫在佛罗里达海峡相对较浅的水域扩散的能力取决于成虫产卵深度和幼虫扩散深度之间的相互作用。在浮游期，幼虫的浮游率、游动行为、摄食需求和个体发育迁移模式将反过来影响扩散深度。最近开发的部署在AUV哨兵上的SyPRID采样器将用于从水柱中精确深度的地层中收集幼虫，包括非常接近海底的地层。在每个区域的三个深度的海底部署的幼虫陷阱将与浮游生物收集一起使用，以确定幼虫在海底的比例。对幼虫和幼体贝壳的稳定氧同位素进行比较，将提供有关幼虫发育温度(从而深度)的信息，对幼虫和幼体贝壳的地球化学分析将确定幼虫是否混合在深层地层中。结合真实生物学参数的海洋环流和颗粒传输模型将被用于预测幼虫在佛罗里达半岛周围不同产卵深度和季节的活动。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Ever since hydrothermal vents and methane seeps were first discovered in the deep ocean more than 40 years ago, scientists have wondered how these isolated communities, fully dependent on underwater "islands" of toxic chemicals, are first colonized by organisms, and how the populations of these specialized animals are exchanged and maintained. These fundamental processes depend on the transport of babies (larvae) by the ocean currents, yet because the larvae are microscopic and diluted in the vastness of the ocean, it is very difficult to determine where and how they drift. This project uses an autonomous underwater vehicle to collect larvae from precise regions of the water column. Larval traps on the bottom and chemical analyses of larval shells will also be used to determine the depths where larvae swim. These findings will provide realistic estimates for mathematical models that show how biology interacts with ocean currents to predict which methane seeps will be colonized by larvae originating at different depths. A detailed knowledge of larval dispersal is needed for conservation and management of the deep sea. Without such information, we cannot know the best placement of marine protected areas, nor can we facilitate the reestablishment of communities impacted by deep-sea mining, drilling, or other human activities. This project will provide hands-on at-sea training for college students to learn the rapidly vanishing skills needed for studies of larvae and embryos in their natural habitats. Learning opportunities will also be available to individuals of all ages through new, interactive exhibits on deep-sea biology and larval ecology produced for small museums and aquaria on the coasts of Oregon, Washington and North Carolina. Reliable estimates of connectivity among metapopulations are increasingly important in marine conservation biology, ecology and phylogeography, yet biological parameters for biophysical models in the deep sea remain largely unavailable. The movements of deep-sea vent and seep larvae among islands of habitat suitable for chemosynthesis have been inferred from current patterns using numerical modeling, but virtually all such models have used untested assumptions about biological parameters that should have large impacts on the predictions. This project seeks to fill in the missing biological parameters while developing better models for predicting the dispersal patterns of methane seep animals living in the Gulf of Mexico and on the Western Atlantic Margin. Despite the existence of similar seeps at similar depths on two sides of the Florida peninsula, the Western Atlantic seeps support only a subset of the species found in the Gulf of Mexico. It is hypothesized that the ability of larvae to disperse through the relatively shallow waters of the Florida Straits depends on an interaction between the adult spawning depth and the dispersal depth of the larvae. Dispersal depth, in turn, will be influenced by larval flotation rates, swimming behaviors, feeding requirements, and ontogenetic migration patterns during the planktonic period. The recently developed SyPRID sampler deployed on AUV Sentry will be used to collect larvae from precise depth strata in the water column, including layers very near the ocean floor. Larval traps deployed on the bottom at three depths in each region will be used in conjunction with the plankton collections to determine what proportion of larvae are demersal. Comparisons of stable oxygen isotopes between larval and juvenile mollusk shells will provide information on the temperatures (and therefore depths) that larvae develop, and geochemical analyses of larval and juvenile shells will determine whether larval cohorts mix among depth strata. Ocean circulation and particle transport modeling incorporating realistic biological parameters will be used to predict the movements of larvae around the Florida Peninsula for various spawning depths and seasons.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.