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重建底层水温：作为大西洋中部未来之窗的全新世历史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，它是在夏季表层水域变暖时形成的，冬季的冷水沿着底部聚集在一起。冷水池面积很大，但随着大陆架水域变暖，其覆盖面积预计将缩小。这个冷水池是两种生活在海底的文蛤物种的家园，一种是海洋快艇，另一种是大西洋冲浪蚌。这些动物，特别是海洋夸哈斯，活得很长。文蛤的生长记录和经历的温度被保存在它们的贝壳中，类似于树的年轮。来自冷水池的活的和化石的贝壳将被用来估计过去约5000年的底层水温。底部温度将与过去影响大西洋中部的气候时期和已知的气候变异性有关。了解冷池变化对于研究大西洋中部地区过去的气候变化和预测未来的变化非常重要。文蛤贝壳的底层水温将表明，文蛤的分布可能会随着气候变暖而发生变化。分布的变化很重要，因为可能会对文蛤渔业产生经济影响。培训本科生和研究生将是该项目的一部分，并将促进海洋学和古气候科学之间的联系。针对K-8学生的教育推广计划以及由国际扶轮艺术联盟组织的协同项目中与科学相关的艺术倡议，将突出要求蛤壳揭示海底水温变化的新颖方法。大西洋中部大陆架上气候变化的历史是由两种长寿的双壳类贝壳记录下来的，这两种双壳类贝类是大西洋冲浪贝类Spisula solidissima和海洋浮游贝类Arctica Island andica。贝壳随着这些文蛤的生长而层层堆积。对贝壳生长轴线上碳(C12/C14)和氧(O16/O18)同位素比率的分析表明，数百至数千年前生长的文蛤所遇到的温度，以及这种温度是如何随季节变化的。贝壳化石的积累被称为死亡组合。从活体贝壳和化石贝壳获得的温度时间序列将用于重建过去约5000年来中大西洋大陆架底层水温的时空重建。每年夏天，当层结将冬季寒冷的水沿着大陆架底部的一层较暖的水困住时，就会形成一个冷水池。将特别注意这个冷水池的可变性。了解大陆架气候变化的历史将提供关于该地区过去气候变化的重要信息，这些变化对两个文蛤物种正在进行的范围转移的影响，并有助于预测未来的范围分布。对重建的底水温度的分析将确定自新冰期开始以来主要气候变化的历史频率和速度以及相应的范围变化。与范围变化相关的潜在气候驱动因素将从重建的底层水温中确定，并与北大西洋其他重建的温度进行比较。将评估底层水温变化对文蛤死亡事件发生时间的影响。重建的底层水温记录将扩大追溯模型的投入，并与中大西洋区域物种分布的变化(来自采集地点的记录)有关。反过来，这些重建提供了前瞻性预测的基础，对生态进程和渔业生产的持续变暖产生了影响。这一努力汇集了具有广泛专业知识的科学家，特别是包括作为首席研究员的年轻研究人员，以及研究生和本科生。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势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.