Copepod Population Dynamics in Hypoxic Coastal Waters: Physical and Behavioral Regulation of Resupply and Advective Losses

PI将从机制上理解循环如何与低氧诱导的行为和生理变化相互作用，从而影响沿海浮游动物的种群动态。他们将通过评估切萨皮克湾缺氧区两种潜在的截然不同的机制来实现这一点，这两种机制影响着桡足类动物Acartia tonsa的动态。第一个假设是，维持低氧地区的桡足类种群需要通过风驱动的横向运输过程中动物的平流(迁徙)来补充。第二个相反的假说是，底层水缺氧改变了扁藻的垂直分布，从而使它们更容易通过河口环流中的地表水运输而受到来自该地区的平流损失(迁出)的影响。他们将利用目前由NSF资助的切萨皮克湾物理海洋学研究项目，该项目将对海湾中部地区的轴向和横向水交换进行全面测量和建模。本研究将使用物理海洋学研究场地作为控制量(CV)，在其中将很好地确定水的海洋交换以及这些交换的驱动机制。PI将对浮游动物进行高分辨率的空间和时间采样，并将数据与低氧地区的桡足类动物行为、死亡率和产卵量的测量相结合。他们将使用一种改进的基于个体的唐氏沼虾生活史模型，结合循环来探索平流、行为、产卵和死亡率对种群动态的综合影响。除了增加我们对切萨皮克湾底层低氧对桡足类种群的影响的了解外，这项研究还将提高我们对浮游动物种群的物理和生物过程调节以及低氧对沿海水域初级生产力和食物网的影响的总体理解。该项目将加强现有的公众教育和外展工作，使公众能够更好地了解切萨皮克湾缺氧的影响。这将通过海洋科学教育卓越中心(COSEE)沿海趋势计划(现在是Horn Point实验室STEM中心学生学习活动计划)部分实现。PIS将通过开发其合成浮游生物模型的在线互动版本，增强现有的一套在线教育模块(http://www.teachoceanscience.net/))，这些模块侧重于切萨皮克湾“死亡区”的原因和后果。这项研究还包括本科生暑期实习生通过本科生研究体验(REU)计划的参与。此外，这项研究将有助于制定和改进切萨皮克湾的溶解氧标准，将通过提供浮游动物在支持渔业生产力方面的作用的信息来支持切萨皮克湾计划的广泛倡议，并将为基于生态系统的渔业管理计划提供信息。

The PIs will develop a mechanistic understanding of how circulation interacts with hypoxia-induced behavioral and physiological changes to affect the population dynamics of coastal zooplankton. They will do this by assessing two potentially contrasting mechanisms influencing the dynamics of the copepod Acartia tonsa in the hypoxic zone of Chesapeake Bay. The first hypothesis is that maintenance of copepod populations in the hypoxic region requires replenishment by advection (immigration) of animals through wind-driven lateral transport processes. The second, counteractive, hypothesis is that bottom water hypoxia alters the vertical distribution of A. tonsa, thereby making them more susceptible to advective losses from the region (emigration) via surface water transport in the estuarine circulation. They will take advantage of a current NSF-funded physical oceanography research program in Chesapeake Bay that will comprehensively measure and model axial and lateral water exchanges in the mid-Bay region. The present study will use the physical oceanography study site as a Controlled Volume (CV) in which the oceanographic exchanges of water and the driving mechanisms for those exchanges will be well defined. The PIs will conduct high-resolution spatial and temporal sampling of zooplankton and combine the data with measurements of copepod behavior, mortality and egg production in the hypoxic region. They will use an improved Individual-Based Model of the life history of A. tonsa coupled with the circulation to explore the combined effects of advection, behavior, egg production, and mortality on population dynamics. In addition to increasing our knowledge of the impacts of bottom water hypoxia on copepod populations in Chesapeake Bay, the study will improve our general understanding of the regulation of zooplankton populations by physical and biological processes and the impacts of hypoxia on secondary production and food webs in coastal waters. The project will enhance existing public education and outreach efforts so that the public can be better informed about the effects of hypoxia on Chesapeake Bay. This will be accomplished in part through the Center for Ocean Science Education Excellence (COSEE) Coastal Trends program (now the Horn Point Laboratory STEM Center Student Learning Activities program). The PIs will enhance an existing set of online education modules (http://www.teachoceanscience.net/) that focus on the causes and consequences of the Chesapeake Bay's "Dead Zone" through development of an online interactive version of their synthetic plankton model. The study also includes participation by undergraduate summer interns through a Research Experience for Undergraduates (REU) program. In addition, this research will contribute information toward the development and improvement of dissolved oxygen criteria for Chesapeake Bay, will support broad initiatives of the Chesapeake Bay Program by providing information on the role of zooplankton in supporting productivity of fisheries, and will contribute information to ecosystem-based fisheries management plans.