Collaborative Research: Fertilization in free-spawners - interaction of gamete properties and hydrodynamic regime

本项目将探索海胆配子的粘度和寿命如何与不同的流动状态相互作用，以确定配子接触的位置以及由此产生的受精和多精受精水平。初步数据表明，在一系列田间条件下，棘球类的受精是一个时间综合的过程，主要发生在雌性的流产表面或紧邻下游的流动结构(涡流)中。因此，受精和多精受精水平可能比早期实验和现有模型预测的要高得多，这些模型将受精视为一个水柱过程。这些假设的组成部分将通过一系列实验室水槽实验进行验证，这些实验将分析配子平流的时间进程、受精地点以及在单向和振荡流动条件下的各种湍流条件下受精和多精受精的水平。补充性野外分析将探索自然产卵发生的流动条件。绿色海胆(Strongyloctrotus Droebachisis)是商业捕捞的，因此缅因州海岸大部分地区的当地种群密度相当低。增加对受精过程和精子可获得性的时间模式的了解，将有助于管理人员评估低密度人群受精失败的可能性及其对种群动态的影响。两个当地的海胆保护区将被用作研究地点，因此研究结果还将帮助管理人员评估小型本地化保护区的繁殖潜力。该项目还将培养学生(本科生和研究生)和博士后。

ABSTRACTThis project will explore how the viscosity and longevity of sea urchin gametes interact with different flow regimes to determine where gametes contact and the resulting level of fertilization and polyspermy. Preliminary data suggest that under a range of field conditions, fertilization in echinoids is a time-integrated process that occurs largely on the aboral surface of the female or in flow structures (eddies) immediately downstream. Consequently, fertilization and polyspermy levels may be much greater than predicted by earlier experiments and existing models that treat fertilization as a water column process. Components of these hypotheses will be tested through a series of laboratory flume experiments that will assay the time course of gamete advection, the site of fertilization, and levels of fertilization and polyspermy under a range of turbulence conditions in both uni-directional and oscillatory flow regimes. Complementary field assays will explore the flow conditions under which natural spawning occurs.The green sea urchin (Strongylocentrotus droebachiensis) is commercially harvested, and local population densities are consequently quite low along much of the Maine coast. Increased understanding of fertilization processes and temporal patterns of sperm availability will help managers evaluate the likelihood of fertilization failure in low density populations and the consequences for population dynamics. Two local sea urchin reserves will be used as study sites, so results will also help managers evaluate the reproductive potential of small, localized reserves. This project will also train students (both undergraduate and graduate) and post-docs.