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，世界海洋的中层水氧气消耗区或氧气最小区正在扩大。随着有机开放区的扩大，预计海洋生态系统的食物网结构和动态以及温室气体的产生将受到干扰，从而对气候系统产生反馈。北方阿拉伯海有一个非常广泛的OMZ，其特点是季风上升流和高藻类初级生产力的强烈季节性变化。虽然该地区的沉积物记录已被广泛研究，以重建自上一次冰期-间冰期循环以来OMZ范围的原因，时间和持续时间，但OMZ变化的长期变化如何影响阿拉伯海过去的生态系统和食物网仍然完全未知。这项研究由来自伍兹霍尔海洋研究所（WHOI）的一组科学家进行，使用沉积古DNA签名的超高通量测序（即，“古生物组”）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用于确定在过去80，000年的关键气候间隔期间受OMZ强度长期波动影响最严重的物种。将利用（分子）地球化学技术重建气候和环境条件的平行变化。在这个项目中，研究小组将使用最近从印度峡谷西北大陆坡上的OMZ中心获得的连续、未受干扰和放射性碳年代测定的沉积物记录。高分辨率的古代DNA记录将极大地帮助改进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应对OMZ条件的长期时期，以及这些生态系统如何适应后，返回一个良好的混合和含氧的水柱。将与联合王国格拉斯哥大学的一名研究人员合作进行生物信息学和数值模拟分析。该项目将为参加麻省理工学院/世界卫生组织海洋学联合方案的一名研究生和两名本科生提供教育机会，这两名本科生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方案招募。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）的流行年度课程“微生物种群结构分析的策略和技术（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.