Collaborative Research: Reconstructing bottom water temperatures from bivalves on the continental shelf: Holocene history as a window to the future in the Mid-Atlantic

从大陆架上的双壳类动物中重建海底水温：全新世历史作为展望中大西洋未来的窗口美国东海岸外的中大西洋大陆架的海水正在迅速变暖。这些大陆架水域有一个独特的特征，即冷池，它是由夏季表层海水变暖将冬季的冷水困在底部形成的。冷池面积很大，但随着大陆架海水变暖，它所覆盖的面积预计会缩小。这个冷水池是两种生活在海底的蛤蜊的家园，海洋蛤和大西洋蛤。这些动物，尤其是海洋quohog，寿命很长。蛤的生长和温度记录被保存在壳中，类似于树木的年轮。来自冷池的活蛤壳和化石蛤壳将被用来估计过去~5000年的底部水温。海底温度将与过去的气候期和已知的影响大西洋中部的气候变化有关。了解冷池的变化对于研究过去的气候变化和预测中大西洋地区未来的变化非常重要。蛤壳的底部水温将显示蛤的分布如何随着气候变暖而变化。分布的变化很重要，因为它可能对蛤蜊渔业产生经济影响。培训本科生和研究生将是这个项目的一部分，并将促进海洋学和古气候科学之间的联系。透过国际扶轮艺术联盟所组织的协同计画，为K-8年级学生所举办的教育外展计划，以及一项与科学相关的艺术倡议，将会强调让蛤蜊揭示海底水温变化的新方法。大西洋中部大陆架气候变化的历史记录在两种长寿的双壳类动物的壳上：大西洋蛤（Spisula solidissima）和海洋蛤（arctic islandica）。随着这些蛤蜊的成长，贝壳会分层沉积。对贝壳生长轴上碳（C12/C14）和氧（O16/O18）同位素比例的分析表明，生长中的蛤蜊在数百至数千年前所遇到的温度，以及这种温度的季节性变化。化石壳的堆积被称为死亡组合。从活壳和化石壳中获得的温度时间序列将用于发展过去~5000年大西洋中部大陆架底水温度的时空重建。每年夏天，当分层将冬季的冷水困在大陆架底部的一层温暖的水下面时，就会形成一个冷水池。将特别注意这个冷池的变化。了解大陆架气候变化的历史将提供该地区过去气候变化的重要信息，这些变化对两种蛤的持续范围变化的影响，并允许预测未来的范围分布。对重建的海底水温的分析将确定自新冰川期开始以来主要气候变化和相应范围变化的历史频率，并在可能的情况下确定其速度。将根据重建的海底水温确定与范围变化有关的潜在气候驱动因素，并与北大西洋的其他重建结果进行比较。将评估底水温变化对蛤死亡事件发生时间的影响。重建的底水温记录将扩展回溯模型的输入，并与中大西洋地区不断变化的物种分布（来自收集地点记录）有关。反过来，这些重建为预测持续变暖对生态过程和渔业生产的影响提供了基础。这项工作汇集了具有广泛专业知识的科学家，特别是包括年轻的研究人员作为主要研究人员，以及研究生和本科生水平的学生。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Reconstructing bottom water temperatures from bivalves on the continental shelf: Holocene history as a window to the future in the Mid-AtlanticThe ocean waters of the Middle Atlantic continental shelf off the east coast of the United States are warming rapidly. These continental shelf waters have a unique feature, the cold pool, that is formed when summer warming of surface waters traps cold winter water along the bottom. The cold pool is extensive but the area it covers is expected to shrink as shelf waters warm. The cold pool is home to two bottom dwelling clam species, ocean quahogs and Atlantic surfclams. These animals, especially ocean quahogs, are long lived. Records of growth and the temperature the clams experienced are preserved in their shells, similar to tree rings. The shells of live and fossil clams from the cold pool will be used to estimate bottom water temperature over the past ~5000 years. The bottom temperatures will be linked to past climate periods and known climate variability that influence the Middle Atlantic. Understanding cold pool changes is important for studying past climate change and projecting future changes for the Middle Atlantic region. The bottom water temperatures from the clam shells will show how clam distributions might change in response to climate warming. Changes in distribution are important because of possible economic impacts on the clam fishery. Training undergraduate and graduate students will be part of this project and will foster linkages between oceanography and paleoclimate science. Educational outreach programs for K-8 students and a science-related art initiative through the Synergy project organized by Art League RI will highlight the novel approach of asking clams to reveal changes in ocean bottom water temperature. The history of climate change on the Middle Atlantic continental shelf is recorded by the shells of two long-lived bivalves, the Atlantic surfclam, Spisula solidissima, and the ocean quahog, Arctica islandica. Shell is deposited in layers as these clams grow. Analysis of the ratios of carbon (C12/C14) and oxygen (O16/O18) isotopes along the growth axes of the shell indicates the temperatures that were encountered by the growing clam hundreds to thousands of years ago, and also how this varied seasonally. The accumulation of fossil shells is termed a death assemblage. The temperature time series obtained from the living and fossil shells will be used to develop spatial-temporal reconstructions of bottom water temperatures on the Middle Atlantic shelf for the past ~5000 years. A cold pool of water forms each summer when stratification traps cold winter water along the shelf bottom below a layer of warmer water. Particular attention will be paid to variability in this cold pool. Understanding the history of climate change on the continental shelf will provide important information on past climatic changes in this region, the impact of these changes on ongoing range shifts of the two clam species, and allow projection of future range distributions. Analyses of the reconstructed bottom water temperatures will determine the historical frequency and, where possible, rapidity of major climatic changes and corresponding range shifts since the beginning of the Neoglacial Period. Potential climate drivers associated with the range changes will be determined from the reconstructed bottom-water temperatures and compared with other North Atlantic reconstructions. The influence of bottom water temperature changes on the timing of clam mortality events will be assessed. The reconstructed bottom water temperature records will extend inputs for retrospective models and be related to changing species distributions (from collection location records) in the Middle Atlantic region. In turn these reconstructions provide the basis for forward projections with implications for continued warming on ecological processes and fishery production. This effort brings together scientists with a broad range of expertise, and notably includes both young investigators as lead investigators, and students at both the graduate and undergraduate level.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.