OCE-PRF The ecological and economic consequences of coastal hypoxia: a case study using a novel in situ benthic observing system, Wormcam

概述：在本项目中，研究员将研究沿海底栖生物系统在原位和低氧条件下的群落结构动态，生理适应在维持底栖生物服务和功能中的作用，以及低氧的经济成本。这项工作将在杜克大学尼古拉斯环境学院海洋实验室的Cindy Lee Van Dover教授的指导下进行。沿海缺氧会对底栖生物群落的结构和功能产生负面影响。虽然缺氧对底栖生物群落结构的影响已经很清楚，但对群落功能的影响却鲜为人知。在缺氧开始时，流动动物被转移，随着缺氧的严重程度和持续时间的增加，非流动动物的群落结构退化（即生物多样性、生物量和活动的丧失）。缺氧的影响可产生生态系统层面的后果，包括依赖动物提供营养的底栖渔业（如底栖鱼类和底栖甲壳类捕食者）的减少；动物群落的退化也降低了生物扰动率，改变了营养物的生物再矿化率和污染物的固存。智力优势：本研究将利用经历持续（切萨皮克湾，弗吉尼亚州）和间歇性（纽瑟河，北卡罗来纳州）季节性缺氧的比较系统来回答以下问题：1)在持续和间歇性缺氧条件下，缺氧与生物扰动率之间的关系是什么？这个问题将通过在两个系统中使用时间序列（每小时）沉积物剖面成像（SPI）和环境传感系统进行为期12个月的底栖生物观测来解决，同时每月进行重复采样，以获得生物扰动率（沉积物剖面）和群落结构（沉积物捕获）的空间特征。研究地点将根据每个系统的缺氧历史来选择，分别使用来自切萨皮克湾底栖生物监测和切萨皮克湾项目和北卡罗来纳大学教堂山海洋科学研究所的纽斯河河口建模和监测项目的数据。2)缺氧与关键系统生物生理反应有何关系？这种关系将使用呼吸测量法和基因表达方法在两种底栖多毛类物种中进行检验，并将检验在切萨皮克湾和纽塞河培养的生物之间存在显著差异的假设。从每个系统中培养的多毛体将进行缺氧试验，使用停止流动呼吸仪来确定代谢率、氧气提取和导致死亡的氧气饱和度。在缺氧试验中，蠕虫的亚样本将被移除并冷冻，用于随后的限制性内切位点相关DNA测序，以调查差异基因表达。3)沿海缺氧的经济成本是什么？该研究员将开发一个生物经济模型，通过将缺氧对底栖生物渔业（如蓝蟹）的影响联系起来，探索切萨皮克湾缺氧的经济成本，并将这些结果与之前在纽塞河进行的缺氧经济评估进行比较。更广泛的影响：研究结果将在科学文献中传播，并将为沿海环境管理人员提供有用的新知识。他将通过杜克大学（Duke University）的指导项目、ASLO多元文化项目和全国黑人水肺潜水员协会（National Association of Black Scuba Divers）的年度青年教育峰会（Youth Education Summit），扩大少数族裔对海洋科学的参与。该协会的目标是对海洋科学感兴趣的小学少数族裔。

Overview: In this project, the fellow will conduct a study of the dynamics of community structure of coastal benthic systems, in situ, and under hypoxic conditions, the role of physiological adaptations in maintaining benthic services and functions, and the economic cost of hypoxia. This work will be undertaken under the mentorship of Professor Cindy Lee Van Dover at the Marine Laboratory of the Nicholas School of the Environment, Duke University. Coastal hypoxia can have negative consequences on benthic community structure and function. While the effects of hypoxia on benthic community structure are well understood, less well known are impacts to community function. At the onset of hypoxia, mobile fauna are displaced, and, as the severity and duration of hypoxia increase, community structure of non-mobile infauna degrades (i.e., loss of biodiversity, biomass, activity). Impacts of hypoxia can have ecosystem-level consequences, including reductions in benthic fisheries that depend on infauna for their nutrition (e.g., demersal fish and epibenthic crustacean predators); degradation of the infauna community also reduces bioturbation rates, altering rates of biogenic remineralization of nutrients and pollutant sequestration. Intellectual Merit: This study will take advantage of comparative systems that experience sustained (Chesapeake Bay, VA) and intermittent (Neuse River, NC) seasonal hypoxia to answer the following questions: 1) What is the relationship between hypoxia and bioturbation rates under sustained and intermittent conditions of hypoxia? This question will be addressed through 12-months of benthic observations in two systems using time-series (hourly) sediment profile imaging (SPI) and environmental sensing systems, together with monthly replicate sampling for spatial characterization of bioturbation rates (sediment profiles) and community structure (sediment grabs). Study locations will be chosen based on the history of hypoxia in each system, using data from the Chesapeake Bay Benthic Monitoring and Neuse River Estuary Modeling and Monitoring Programs of the Chesapeake Bay Program and University of North Carolina Chapel Hill's Institute of Marine Science, respectively. 2) What is the relationship between hypoxia and physiological response of key system organisms? This relationship will be examined using respirometry and gene expression methodologies in two benthic polychaete species, and will test the hypothesis that there are significant differences in response between organisms cultured from Chesapeake Bay and the Neuse River. Cultured polychaetes from each system will be put through hypoxia trials using stop-flow respirometry to determine metabolic rate, O2 extraction, and the O2 saturation level that induces mortality. Subsamples of worms will be removed and frozen at intervals in the hypoxia trials for subsequent Restriction site Associated DNA sequencing to survey for differential gene expression. 3) What is the economic cost of coastal hypoxia. The fellow will develop a bioeconomic model that explores the economic costs of hypoxia in Chesapeake Bay by relating hypoxic affects to a benthic fishery (i.e. blue crabs), and compare those results with economic valuations of hypoxia previously conducted in the Neuse River. Broader Impacts: Research results will be disseminated in the scientific literature and will provide new knowledge useful to coastal environmental managers. The fellow will expand efforts to broaden the participation of minorities in ocean science through mentoring programs at Duke University, in the ASLO Multicultural Program, and in the annual Youth Education Summit of the National Association of Black Scuba Divers, which targets grade school minorities with an interest in ocean science.