Horizontal and Vertical Distribution of Thecosome Pteropods in Relation to Carbonate Chemistry in the Northwest Atlantic and Northeast Pacific

海洋酸化对海洋生态系统的影响是海洋科学家和海洋资源管理者面临的一个重要问题。翼足类是一类钙质浮游软体动物，广泛分布于S大洋沿岸和开阔大洋的远洋生态系统中。这些动物分泌文石外壳，因此由于水柱的碳酸盐化学变化，特别是文石补偿深度的浅化，海水对文石具有腐蚀性，因此对海洋酸化高度敏感。然而，在许多地区，人们对翼足类的丰度、分布、垂直迁徙行为和生态重要性知之甚少。评估海洋酸化引起的翼足类动态变化的可能生态后果将需要详细了解翼足类的分布和丰度相对于水柱中文石饱和度的变化。该项目的主要目标是量化大西洋西北部和东北太平洋海洋生态翼足类的分布、丰度、物种组成、贝壳状况和垂直迁徙行为，并将这些量与水文地理学和同时测量的碳酸盐化学，包括文石饱和度的垂直和水平分布相关联。特别是，该项目将利用大西洋和太平洋内部和之间文石饱和度深度分布的当今可变性，作为一项“自然实验”，以解决翼足类垂直分布、物种组成和丰度随着补偿深度变浅而变化的假设。次要目标是制定遥测翼足类丰度的声学协议，以便今后纳入海洋酸化监测网络，并确定两条WOCE/CLIVAR重复水文断面(大西洋A20和太平洋P17N)沿线的碳酸盐化学和营养物质特征，以查明碳酸盐系统的十年尺度变化。这些假设和目标将通过沿西北大西洋和东北太平洋北纬35度至50度的调查横断面的两次巡航来解决，涉及站位工作和正在进行的测量相结合，以及一系列全面的仪器，包括声学、光学、网络、水文和碳酸盐化学传感器。智力优势：这是一个高度跨学科的项目，结合了浮游动物生态学、声学和海洋化学的专业知识。这种协作以及同时就地部署新的生物和化学传感器是研究海洋酸化及其影响的关键下一步，因为以前关于海洋酸化的生物影响的观察性研究很少。拟议的工作将使人们对西北大西洋和东北太平洋生态系统翼足类动物的水平和垂直分布以及物种组成的变异性有一个详细的基线了解，从而对浮游动物生态作出总体上的关键贡献。此外，通过量化大西洋和太平洋内部和之间对当前空间变异性的响应，该项目将提供有关翼足类分布对文石饱和度垂直分布未来变化的可能响应的重要信息，文石饱和度是模拟海洋酸化对海洋生态系统功能、服务和资源影响的必要组成部分。翼足类是各种商业开发鱼种的主要猎物，PI对翼足类分布的更好理解以及对水柱碳酸盐化学变化的可能反应将对我们理解海洋酸化对海洋资源的潜在影响具有重要意义。该项目还将以多种方式将研究与教育结合起来，包括对本科生和研究生进行跨学科培训，并将数据和研究结果纳入以课程为基础的教学。对这项工作的描述、其发现以及对生态/保护的影响将通过一系列门户网站进行传播，将“远洋蜗牛”作为海洋酸化影响浮游生物的典范。

The impact of ocean acidification on marine ecosystems represents a vital question facing both marine scientists and managers of ocean resources. Thecosome pteropods are a group of calcareous planktonic molluscs widely distributed in coastal and open ocean pelagic ecosystems of the world¡¦s oceans. These animals secrete an aragonite shell, and thus are highly sensitive to ocean acidification due to the water column's changing carbonate chemistry, and particularly the shoaling of the aragonite compensation depth at which seawater becomes corrosive to aragonite. In many regions, however, relatively little is known about the abundance, distribution, vertical migratory behavior, and ecological importance of pteropods. Assessing the likely ecosystem consequences of changes in pteropod dynamics resulting from ocean acidification will require a detailed understanding of pteropod distribution and abundance relative to changing aragonite saturation in the water column.The primary objective of this project is to quantify the distribution, abundance, species composition, shell condition, and vertical migratory behavior of oceanic thecosome pteropods in the northwest Atlantic and northeast Pacific, and correlate these quantities to hydrography and concurrent measurements of carbonate chemistry, including vertical and horizontal distributions of aragonite saturation. In particular, the project will capitalize on present-day variability in the depth distribution of aragonite saturation levels within and between the Atlantic and Pacific Oceans as a "natural experiment" to address the hypotheses that pteropod vertical distribution, species composition, and abundance vary as the compensation depth becomes shallower. Secondary objectives are to develop acoustic protocols for the remote quantification of pteropod abundance for future integration into ocean acidification monitoring networks, and to characterize carbonate chemistry and nutrients along portions of two WOCE/CLIVAR Repeat Hydrography transects (A20 in the Atlantic and P17N in the Pacific) to identify decadal-scale changes in the carbonate system. These hypotheses and objectives will be addressed through two cruises along survey transects between 35 and 50 degrees N in the northwest Atlantic and northeast Pacific involving a combination of station-work and underway measurements, and a comprehensive array of instruments, including acoustic, optical, net, hydrographic, and carbonate chemistry sensors.Intellectual Merit: This is a highly inter-disciplinary project, combining expertise in zooplankton ecology, acoustics, and marine chemistry. Such collaboration and the concurrent in situ deployment of newly-available biological and chemical sensors represent critical next steps in the study of ocean acidification and its impacts, since previous observational studies of the biological impact of ocean acidification have been few. The proposed work will result in a detailed baseline understanding of variability in the horizontal and vertical distribution, as well as species composition, of thecosome pteropods in the northwest Atlantic and northeast Pacific, making a key contribution to zooplankton ecology generally. In addition, by quantifying the response to current spatial variability within and between the Atlantic and Pacific Oceans, the project will provide important information on the likely response of pteropod distribution to future changes in the vertical distribution of aragonite saturation levels, a necessary component in modeling the impacts of ocean acidification on marine ecosystem function, services, and resources.Broader Impacts: Ocean acidification is increasingly appreciated as an urgent societal concern. Thecosome pteropods are key prey for a variety of commercially-exploited fish species, and the improved understanding the PIs seek of pteropod distribution and likely response to changing water column carbonate chemistry will have important implications for our understanding of potential effects of ocean acidification on marine resources. The project will also integrate research with education in a number of ways, including the inter-disciplinary training of undergraduate and graduate students and incorporation of the data and findings into course-based teaching. Descriptions of the work, its findings, and ecological/conservation implications intelligible to a lay audience will be disseminated via a combination of web portals, advancing "pelagic snails" as a poster child of the planktonic impacts of ocean acidification.