Physical and Biological Processes Linking the Sources of Larval Production to Subsequent Recruitment into Subtidal Benthic Communities

该项目将调查幼虫生产、分布、定居和招募之间的相互作用，并确定这些因素如何影响潮下底栖生物群落结构和物种组成的差异。先前使用新开发的自动采样设备进行的研究表明，许多无脊椎动物物种的招募发生在淡水期，特别是在退潮时。这种模式可以解释为什么一些底栖物种即使在动荡的环境中也能保持当地持久的种群。为了评估这一发现的普遍性，Osman博士和合作者将进行一系列的实地调查，主要有四个目标。首先，他们将研究潮汐流体动力学和围堰内的相关运输，以建立水运动、幼虫分布和招募之间的模式和相关性。其次，科学家们将调查幼虫生产、释放、可得性和招募之间的时空关系。实验将集中在三组不同的物种上；第一类具有强大的本地来源，但幼虫寿命较短（小时）（殖民地海鞘，苔藓虫）；第二类具有同样强大的本地来源，但幼虫寿命较长（天）（一些孤立的海鞘）；第三类具有分布的区域来源，幼虫寿命较长（如藤壶）。第三，研究人员将研究招募如何影响更大区域人口中亚种群的建立和长期维持。实验将量化新移民到一个地区，确定他们的存活率，评估他们复制和成为当地人口的能力，并通过多代检查随后的人口维持情况。实地研究将结合新开发的测量底栖物种幼虫和新物种的设备，以及测量大范围洋流和局部湍流强度的标准技术。最后，将建立一个数值模型来预测不同生活史物种的幼虫和新兵的空间分布。该模型将潮汐的知识与从实验中获得的幼虫生产、分布、定居和招募的定量描述结合起来。该模型对这些因素的合理变化的敏感性将用于评估我们预测海洋种群和群落动态的时空变化的能力。

Whitlach9819489This project will investigate the interplay between larval production, distribution, settlement, and recruitment and to determine how these factors influence differences in the structure and species composition of subtidal benthic communities. Previous studies using a newly developed automated sampling device indicate that recruitment of many invertebrate species occurs during slack water periods, particularly at low tide. This pattern may explain how some benthic species can maintain locally persistent populations even in turbulent environments. To assess the generality of this finding, Dr. Osman and collaborators will conduct a series of field investigations with four primary objectives. First, they will examine tidal hydrodynamics and associated transport withip an embayment in order to establish the patterns and correlations among water movement, larval distributions, and recruitment. Second, the scientists will investigate the spatial and temporal relationships between larval production, release, availability, and recruitment. Experiments will focus on three distinct groups of species; one with strong local source areas and shortlived (hours) larvae (colonial ascidians, bryozoans), a second group with equally strong local sources but with longer-lived (days) larvae (some solitary ascidians), and the third with a distributed regional source of long-lived larvae (e.g. barnacles). Third, investigators will examine how recruitment influences the establishment and long-term maintenance of sub-populations within a larger regional population. Experiments will quantify the immigration of recruits into an area, determine their survival rates, evaluate their ability to replicate and become a local population, and examine subsequent population maintenance through multiple generations. The field studies will combine newly-developed devices for measuring larvae and recruits of benthic species with standard techniques for measuring large-scale currents and local turbulence intensities. Finally, a numerical model will be developed to predict spatial distributions of larvae and recruits for species with different life histories. The model will combine knowledge of tidal flows with quantitative descriptions of larval production, distribution, settlement, and recruitment obtained from experiments. The model's sensitivity to plausible variations in these factors will be used to assess our ability to predict spatial and temporal variability in marine population and community dynamics.