Collaborative Research: Ocean Acidification: Impacts on copepod populations mediated by changes in prey quality

研究表明，海洋酸化（OA）会对个体生物产生生理后果，即使是那些缺乏碳酸钙骨架结构的生物。然而，这项研究并没有充分说明OA对个体的影响是如何在营养水平上联系起来的。浮游桡足类是大多数海洋生物地球化学循环的关键参与者。它们对浮游植物和微型浮游动物的消耗是细菌和浮游植物生产转移到更高营养级的主要机制。尽管他们的高丰度和生态的重要性，桡足类已经收到了关于OA的研究很少关注。少数研究集中在pCO 2升高对桡足类的直接急性影响（例如卵孵化、存活），在预测的未来pCO 2下观察到的显著影响很少。然而，人们越来越认识到，OA显着影响他们的浮游植物猎物，包括提高生长速度，增加细胞大小，改变营养吸收和比例，和化学成分。由于桡足类放牧，产卵，孵化成功率都可以与这些猎物的特点，OA介导的浮游植物质量的变化可能是一个重要的间接机制，通过OA作用于桡足类种群，并最终，海洋食物网。这项研究将促进我们的理解，桡足类种群可能会受到OA的影响，特别是通过OA引起的浮游植物质量的变化。本研究的核心目标是确定浮游植物的生理和生物化学（如脂质成分）的变化如何影响桡足类产卵，孵化和无节幼体的个体发育。PI将包括一个子集的实验，以测试OA是否影响桡足类动物的繁殖输出独立的猎物的变化。为了实现这些研究目标，硅藻，Ditylum brightwellii和甲藻，海洋原甲藻，将在几种pCO 2浓度下半连续培养，在此期间，研究人员将表征其生理和生物化学的变化。桡足类，Calanus pacificus，一个大的，高脂的海洋物种，和Acartia clausi，一个较小的，低脂的河口物种，将保持在不同的pCO 2浓度和喂养这些pCO 2驯化的猎物，和他们的放牧和繁殖能力量化。在这项研究中使用的桡足类和浮游植物将收集从萨利希海，该地区已经经历了高pCO 2/H+（1000 ppm，pH值7.5）在不同的时间尺度的时期。因此，这项研究解决了未来气候变化如何影响海洋生态系统的问题，但也与目前沿海环境中经历的pCO 2/H+变化有关。 更广泛的影响：该项目的PI致力于：1）促进获得代表性不足的群体，2）培训和指导，3）扩大OA的知识和4）为正在进行的多学科OA研究开发基础设施。代表性不足的群体将通过香农点海洋中心（SPMC）的国家认可的NSF资助的海洋科学多文化倡议：本科生参与（MIMUNK：http：//www.wwu.edu/mimsup/）和华盛顿的太平洋西北路易斯斯托克斯少数民族参与联盟（PNW LSAMP）计划。教育目标通过一系列活动来实现，包括K-12外展、本科生研究经验（包括SPMC的夏季REU计划）以及广泛传播的课程材料的开发。该项目将支持和参与SPMC？海洋事务厅还通过海洋事务厅的公众外联倡议，提高公众对海洋问题的认识。这项研究将支持三名早期职业科学家，一名公共教育外展专家，并将培训一名博士后研究员和一名研究生。对SPMC现有OA研究设施的基础设施改进将提高可用性，使其更容易用于课堂使用和学生研究。增加的仪器还将使该设施成为监测萨利希海pCO 2的区域资源。

Research shows that ocean acidification (OA) has physiological consequences for individual organisms, even those lacking calcium carbonate skeletal structures. However, this research does not adequately address how OA effects to individuals are linked across trophic levels. Pelagic copepods are critical players in most marine biogeochemical cycles. Their consumption of phytoplankton and microzooplankton is the primary mechanism by which bacterial and phytoplankton production is transferred to higher trophic levels. Despite their high abundance and ecological importance, copepods have received little research attention concerning OA. The few studies focused on direct acute effects to copepods (e.g. egg hatching, survival) under elevated pCO2, and few significant effects have been observed at predicted future pCO2. However, there is increasing recognition that OA significantly affects their phytoplankton prey, including elevating growth rates, increasing cell sizes, altering nutrient uptake and ratios, and chemical composition. Because copepod grazing, egg production, and hatching success all can vary with these prey characteristics, OA mediated changes in phytoplankton quality may be an important indirect mechanism through which OA acts on copepod populations and, ultimately, marine food webs. This study that will advance our understanding of how copepod populations may be affected by OA, specifically through OA induced changes in phytoplankton quality. The core objective of this study is to determine how changes in phytoplankton physiology and biochemistry (e.g. lipid composition) affect copepod egg production, hatching, and ontogenetic development of nauplii. The PIs will include a subset of experiments to test whether OA affects copepod reproductive output independent of changes to prey. To achieve these research goals, the diatom, Ditylum brightwellii, and dinoflagellate, Prorocentrum micans, will be cultured semi-continuously under several pCO2 concentrations, during which time the investigators will characterize changes in their physiology and biochemistry. The copepods, Calanus pacificus, a large, high lipid-bearing marine species, and Acartia clausi, a smaller, low lipid-bearing estuarine species, will be maintained across varying pCO2 concentrations and fed these pCO2-acclimated prey, and their grazing and reproductive capability quantified. The copepods and phytoplankton used in this study will be collected from the Salish Sea, a region already experiencing periods of high pCO2/H+ (1000 ppm, pH 7.5) on varying timescales. Therefore, this research addresses a question of how future climate change may impact marine ecosystems, but also is relevant to pCO2/H+ variability presently experienced in coastal environments. Broader Impacts: The PIs of this project are committed to: 1) promoting access to under-represented groups, 2) training and mentoring, 3) broadening knowledge of OA and 4) developing infrastructure for ongoing, multidisciplinary OA research. Under-represented groups will be served through Shannon Point Marine Center's (SPMC) nationally recognized NSF-funded Multicultural Initiative in the Marine Sciences: Undergraduate Participation (MIMSUP: http://www.wwu.edu/mimsup/), and University of Washington's Pacific Northwest Louis Stokes Alliance for Minority Participation (PNW LSAMP) programs. Educational goals are addressed through an array of activities including K-12 outreach, research experiences for undergraduates, including SPMC's summer REU program, and development of widely disseminated curricular materials. The project will support and participate in SPMC?s public outreach initiative, increasing awareness of marine issues in the general public. This study will support three early career scientists, a public education outreach specialist, and will train a postdoctoral researcher and a graduate student. Infrastructure improvements to SPMC's existing OA research facility will increase usability, making it more accessible for classroom use and student research. The additional instrumentation will also allow the facility to become a regional resource for monitoring pCO2 in the Salish Sea.