CAREER: Environmental Forcing on the Resilience of Carbonate Platforms During the Early Cretaceous Super Greenhouse Period

浅海珊瑚礁系统支持着高度多样化的群落。然而，这些产生碳酸盐的系统中约有75%受到持续变暖和人类活动增加的威胁。调查地球历史可以增进对这些脆弱系统的了解，并为确定减缓进程提供机会。大约1.2亿年前，大气中温室气体的含量急剧增加。在这样的条件下，浅海产碳酸盐生态系统要么存活、适应，要么消失。该提案将通过考察从古赤道到亚热带的四个不同纬度的地点，来检验产生碳酸盐的生态系统在低纬度地区更有弹性的假设。该项目将包括为从当地社区大学招募的少数族裔学生提供研究机会。学生们将参加一个暑期实习项目，该项目包括多层次的指导方法，旨在提高他们对地球科学的兴趣和对该专业的忠诚度。学生将有机会发表他们的研究成果，并成为其他少数民族学生的榜样。该项目将通过调查法国、意大利和阿曼保存的碳酸盐平台，将生态系统的适应与海洋缺氧事件（OAE） 1a相关的环境恶化联系起来。这些地区在OAE1a时期处于不同的纬度，经历了不同的气候和风化条件。碳酸盐岩台地或在古高纬度地区消失，或在海底环境中转变为微生物群落。确定有利于这些生态系统恢复能力的参数需要识别与OAE1a相关的碳循环和化石组合中的扰动，并使用地球化学代理评估相关的环境压力。完成这些任务将加深对环境和碳酸盐生产之间反馈机制的认识，量化超级温室条件下的热和养分纬度梯度，并提高对全球古海洋学扰动期间生态系统恢复力的理解，这可能有助于减轻现代珊瑚礁系统的消亡。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。

Shallow marine reef systems support a highly diversified community. Yet, approximately 75% of these carbonate-producing systems are threatened by ongoing warming and increased human activity. Investigating the Earth's history can increase understanding of these vulnerable systems and provide opportunities for identifying mitigation processes. About 120 million years ago, the atmospheric content of greenhouse gases increased dramatically. Under such conditions, shallow marine carbonate-producing ecosystems either survived, adapted, or disappeared. This proposal will test the hypothesis that the resilience of carbonate-producing ecosystems was favored at low latitudes by examining four locations at different latitudes, from the ancient equator to the subtropics. This project will include research opportunities for underrepresented minority students recruited from a local community college. The students will participate in a summer internship program that includes a multitiered mentoring approach and is designed to increase interest in geoscience and retention in the major. Students will have the opportunity to publish their research and serve as role models for other minority students.This project will link the adaptation of ecosystems to environmental deteriorations associated with the Oceanic Anoxic Event (OAE) 1a, by investigating carbonate platforms preserved in France, Italy, and Oman. These areas were located at different latitudes during the OAE1a and experienced diverse climate and weathering conditions. Carbonate platforms either disappeared at high paleolatitudes or transitioned into microbial communities in subequatorial settings. Determining parameters that favor the resilience of these ecosystems requires the identification of the perturbations in the carbon cycle and in the fossil assemblage associated with the OAE1a, and the appraisal of associated environmental stresses using geochemical proxies. Achieving these tasks will deepen the knowledge on feedback mechanisms between the environment and carbonate production, quantify thermal and nutrient latitudinal gradients under super greenhouse conditions, and improve the understanding of the resilience of ecosystems during a period of global paleoceanographic perturbation that could serve to mitigate the demise of modern reef systems.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.