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

自从40多年前在深海中首次发现热液喷口和甲烷渗漏以来，科学家们一直想知道这些完全依赖有毒化学物质的水下“岛屿”的孤立群落是如何首先被生物占领的，以及这些特殊动物的种群是如何交换和维持的。这些基本的过程依赖于洋流对幼体（幼体）的运输，然而，由于幼体在浩瀚的海洋中非常微小和稀释，很难确定它们在哪里以及如何漂流。该项目使用自主水下航行器从水柱的精确区域收集幼虫。海底的幼虫陷阱和幼虫壳的化学分析也将用于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，这些模型显示生物如何与洋流相互作用，以预测来自不同深度的幼虫将在哪些甲烷渗漏处定居。对深海的保护和管理需要详细了解幼虫的扩散情况。没有这些信息，我们就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，让他们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。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学的新的互动式展览，所有年龄的个人都可以获得学习机会。在海洋保护生物学、生态学和系统地理学中，对超种群间连通性的可靠估计越来越重要，但深海生物物理模型的生物学参数在很大程度上仍然不可用。深海喷口和渗漏幼虫在适合化学合成的栖息地岛屿之间的运动已经通过使用数值模拟从目前的模式中推断出来，但实际上所有这些模型都使用了未经检验的关于生物参数的假设，这些假设对预测应该有很大的影响。该项目旨在填补缺失的生物学参数，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的相似深度存在类似的渗漏，但西大西洋的渗漏只支持墨西哥湾发现的物种的一小部分。据推测，幼虫在佛罗里达海峡相对较浅的水域中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。在浮游生物时期，幼虫的漂浮率、游动行为、摄食需求和个体迁移模式会影响扩散深度。最近开发的SyPRID采样器部署在AUV Sentry上，将用于从水柱的精确深度地层收集幼虫，包括非常接近海底的地层。在每个区域的三个深度的底部部署的幼虫陷阱将与浮游生物收集一起使用，以确定海底的幼虫比例。比较幼体和幼体软体动物外壳之间的稳定氧同位素将提供幼体发育的温度（从而提供深度）信息，对幼体和幼体外壳的地球化学分析将确定幼体群体是否在深层地层中混合。结合现实生物学参数的海洋环流和粒子输运模型将用于预测佛罗里达半岛周围不同产卵深度和季节的幼虫运动。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值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.