CAREER: Future Oxygen minimum zones in Indo-Pacific Ocean: ventilation, biogeochemical feedbacks and risk of coastal dead zones

在全球变暖和其他人类对海洋的影响的许多后果中，海水氧浓度普遍下降，在某些地区，海洋氧最低区（OMZs）和沿海“死亡区”明显扩大。印度洋和太平洋是特别大的海洋管制区，印度洋人口稠密国家周围的沿海水域容易成为死亡区。海洋保护区的扩张和沿海死亡区威胁着海洋生物，包括对当地人口和生态系统服务（如渔业和旅游业）有价值的物种。更大的omz也会产生更多的一氧化二氮，一种强有力的温室气体。尽管具有这种重要性，但对于这些威胁在未来将如何演变，还没有达成共识。该CAREER奖将使用地球系统模型（esm）来检查一系列物理、化学和生物过程，这些过程结合在一起产生omz和死区，并研究自然过程和人类活动如何改变它们。首席研究员将在中学阶段开展关于气候变化和缓解的教育活动。这项活动将引导教师和学生探索人类活动的影响和缓解战略，包括“骑自行车的星球”等发人深省的缓解计划。它将在当地中学教师和学生中进行测试，并在一个同行评议的网络平台上公开分享。过去二十年的许多研究都强调了未来对极空区预测的巨大差异。完善这些预测的一个挑战是，先前的机制工作一般只考虑omz的分区域或孤立地考虑一种物理或生物机制的影响。本项目将建立并扩展这一工作体系，以提供一种全面的理解，将通风途径和生物地球化学反馈与印度洋-太平洋盆地规模的海洋生态区联系起来，包括在很大程度上被忽视的关键过程，如印度尼西亚通流或人为气溶胶沉积（目标1和2）。该项目将利用来自耦合模式比较项目6 （CMIP6）的最先进的ESM集合和新颖的海洋生物物理模型，结合现有的观测约束，旨在缩小未来OMZ预测的范围。该项目还将首次评估印度洋沿海死亡区的风险，采用高分辨率区域生物物理模型，该模型结合了广泛的关键自然和人为过程，从当地（河流排放、涡流）到全球（海洋环流扩展、季风变化）尺度（目标3）。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。

Among the many consequences of global warming and other human impacts on the oceans are a general decrease in seawater oxygen concentrations and, in some areas, pronounced expansion of ocean oxygen minimum zones (OMZs) and coastal “dead zones.” The Indian and Pacific Oceans are areas of particularly large OMZs, and coastal waters surrounding densely populated countries in the Indian Ocean are prone to dead zones. OMZ expansion and coastal dead zones threaten marine life, including valuable species for local populations and ecosystem services such as fisheries and tourism. Larger OMZs would also produce more nitrous oxide, a potent greenhouse gas. Despite this importance, there is no consensus on how these threats will evolve in the future. This CAREER award will use Earth system models (ESMs) to examine the suite of physical, chemical, and biological processes that combine to produce OMZs and dead zones, and study how natural processes and human activities change them. The lead investigator will develop an educational activity on climate change and mitigation at the middle-school level. This activity will guide teachers and students to explore the effects of human activities, and mitigation strategies including thought- provocative mitigation plans such as "a cyclist planet". It will be tested with local middle-school teacher and students and shared publicly on a peer-reviewed web platform. Numerous studies in the past twenty years have highlighted strong discrepancies in future projections of OMZs. One challenge to refine these projections is that prior mechanistic work generally considered sub-regions of OMZs or the effect of one physical or biological mechanism in isolation. This project will build upon and expand this body of work to provide a comprehensive understanding that connects ventilation pathways and biogeochemical feedbacks to the OMZs at the scale of the Indo-Pacific basin, including largely overlooked key processes such as the Indonesian Throughflow or anthropogenic aerosol deposition (Objectives 1 and 2). This project will harness the state-of-the-art ESM ensemble from the Coupled Model Intercomparison Project 6 (CMIP6) and novel ocean biophysical models in combination with existing observational constraints with the aim to narrow down future OMZ projections. This project will also assess for the first time the risk of coastal dead zones in the Indian Ocean, using a high-resolution regional bio-physical model that incorporates the wide range of key natural and anthropogenic processes, from local (river discharge, eddies) to global (OMZ expansion, monsoon changes) scales (Objective 3).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.