Oxygen Minimum Zone Variability and Ecosystem Responses in the Arabian Sea during the Last Glacial-interglacial Cycle:A Paired Paleogenomic and (Isotopic) Lipid Biomarker Approach

现有的监测数据表明，在全球变暖的背景下，世界海洋中的氧气枯竭区域或氧气最小区域(OMZ)正在扩大。随着海洋保护区的扩大，海洋生态系统预计将在食物网的结构和动态以及温室气体的生产方面经历扰动，从而对气候系统产生反馈。阿拉伯海北部有一个异常广泛的OMZ，其特点是季风上升流的季节性变化很强，藻类初级生产力很高。尽管已经对该区域的沉积物记录进行了广泛研究，以重建自上一次冰川-间冰期循环以来大洋中层带范围的原因、时间和持续时间，但大洋中层带变化的长期变化如何影响了阿拉伯海过去的生态系统和食物网仍是完全未知的。这项研究由伍兹霍尔海洋研究所(WHOI)的一组科学家进行，利用对沉积的古代DNA签名(即“古生物群”)进行的超高通量测序来重建过去的海洋生物种群。先进的生物信息学和统计工具将被用来确定在过去80,000年的关键气候间隔期间，受OMZ强度长期波动影响最大的物种。气候和环境条件的平行变化将使用(分子)地球化学技术重建。在这个项目中，研究小组将使用最近从印度河峡谷西北大陆坡的OMZ中心获得的连续、未受干扰的放射性碳测年沉积物记录。高分辨率的古代DNA记录将极大地帮助完善受季风影响的阿拉伯海东北部地区过去的环境和气候解释。这项研究将深入了解生态系统将如何对OMZ条件的长期时期做出反应，以及这些生态系统在恢复充分混合和充氧的水柱后如何适应。生物信息学和数值模型分析将与联合王国格拉斯哥大学的一名研究人员合作进行。该项目将为参加麻省理工学院/世界卫生组织海洋学联合项目的一名研究生和两名本科生提供教育机会，他们将通过世界卫生组织的暑期学生奖学金和少数民族奖学金计划招募。此外，这项研究的结果和生物信息学方法将在伍兹霍尔海洋生物实验室(MBL)广受欢迎的年度课程“分析微生物种群结构的战略和技术(STAMPS)”的讲座中实施。

Available monitoring data suggest that mid-water oxygen depletion regions, or Oxygen Minimum Zones (OMZs), are expanding in the world's oceans in the context of global warming. As OMZs expand, marine ecosystems are expected to experience disturbances in the structure and dynamics of food webs and in the production of greenhouse gasses, with resulting feedbacks on the climate system. The northern Arabian Sea has an exceptionally widespread OMZ characterized by a strong seasonal variability of monsoonal upwelling and high algal primary productivity. Although sediment records from the region have been extensively studied to reconstruct causes, timing, and duration of OMZ extent since the last glacial-interglacial cycle, it remains entirely unknown how long-term changes in OMZ variability has impacted past ecosystems and food webs in the Arabian Sea. This research, conducted by a team of scientists from the Woods Hole Oceanographic Institution (WHOI), uses ultra-high-throughput sequencing of sedimentary ancient DNA signatures (i.e., the "paleome") to reconstruct past populations of marine organisms. Advanced bioinformatics and statistical tools will be used to identify species that were most strongly impacted by long-term fluctuations in OMZ strength during key climate intervals over the last 80,000 years. Parallel changes in climate and environmental conditions will be reconstructed using (molecular) geochemical techniques. For this project the research team will use a continuous, undisturbed and radiocarbon-dated sediment record that was recently obtained from the center of the OMZ on the continental slope northwest of the Indus Canyon.The high-resolution ancient DNA records will greatly help to refine past environmental and climate interpretations in the monsoon-impacted northeastern Arabian Sea area. This study will provide insights into how ecosystems will respond to long-term periods of OMZ conditions and how these ecosystems adapt after the return of a well-mixed and oxygenated water column. Bioinformatics and numerical modeling analyses will be carried out in collaboration with a researcher from the University of Glasgow in the United Kingdom. The project will provide educational opportunities for a graduate student enrolled in the MIT/WHOI joint program in oceanography and for two undergraduate students, who will be recruited through WHOI's Summer Student Fellowship and Minority Fellowship programs. In addition, results and bioinformatics approaches from this study will be implemented in a lecture during the popular annual course "Strategies and Techniques for Analyzing Microbial Population Structure (STAMPS)" at the Marine Biology Laboratory (MBL) in Woods Hole.