Collaborative Research: Physiological Plasticity and Response of Benthic Foraminifera to Oceanic Deoxygenation

随着目前世界各地海洋中耗氧性栖息地的扩大，生物适应和维持这种条件的能力将是维持生命的关键。被称为有孔虫的单细胞生物为研究海洋生物对缺氧的生理反应提供了一个独特和相关的机会。此外，考虑到在不断变化的环境下改变其新陈代谢的能力，以及由于化石被广泛用于解释历史气候条件，对它们生理反应的更好理解将增强我们理解过去和预测未来对地球海洋环境变化的反应的能力。这一合作项目还包括教育和外联活动。除了为两名博士后研究人员提供部分资金和全面培训支持外，至少有三名本科生将通过参加一次研究游轮获得第一手海洋经验。我们还计划从一个代表性不足的群体中招募一名本科生加入该项目，进行暑期实习。最后，通过艺术科学的合作将产生一个巡回艺术展，描绘生活在低氧环境中的海洋生物的困境。该项目将确定有孔虫的综合遗传、代谢和生理反应如何允许它们在环境引起的氧气波动中生存。其目的是确定生态生理上不同的有孔虫对氧气供应的生理和代谢反应。在从有氧、缺氧、缺氧到硫化物的沉积物中，将调查三种有孔虫。最初，单细胞基因组分析将揭示它们的生理和代谢潜力。识别基因组中编码的代谢功能将能够预测它们对不断变化的分子氧条件的生理反应，并允许比较这些不同生态型之间的代谢潜力。随后的实验条件将专门测试和验证基因组使能的预测，即适应不断变化的氧气浓度。将基因组数据与生理和化学测量相结合，将构建模型来表示不同氧气制度和地球化学条件下全硫酸盐的代谢活动。这些模型将阐明促进有孔虫在曝气、缺氧、缺氧和正己烷条件下适应的代谢机制，并将利用qPCR分析和生理分析进一步评估关键的C、N、O和S代谢途径的预测变化。这些假说的目的是：1)确定不同氧气制度下有孔虫的生理和代谢潜力；2)确定在不同氧气制度下孵化的每个物种在周期性和长期暴露后的代谢反应；以及3)确定不同氧气制度下氧化应激和ROS产生对不同有孔虫健康和生理的影响。

With the current expansion of oxygen-depleted habitats in oceans around the world, the capacity for organisms to adapt and persist in such conditions will be essential to sustain life. Single-celled organisms called foraminifera present a unique and relevant opportunity in which to study the physiological response of marine life to oxygen-depletion. Additionally, given the ability to modify their metabolism under changing environments and because fossil foraminifera are used extensively for interpretations of historical climate conditions, an improved understanding of their physiological responses will bolster our ability to understand past, and predict future, responses to environmental change in Earth's oceans. This collaborative project also includes education and outreach activities. Along with providing partial financial and full training support to two Postdoctoral Investigators, at least three undergraduate students will gain first-hand oceanographic experience by joining a research cruise. We also plan to recruit an undergraduate student from an underrepresented group to join the project for a summer internship. Lastly, a Science-through-Art collaboration will produce a traveling art exhibition depicting the plight of marine species living in low-oxygen settings. This project will identify how the integrative genetic, metabolic, and physiological response of foraminifera allows their survival under environmentally induced fluctuations in oxygen. The goal is to determine the physiological and metabolic responses of ecophysiologically distinct foraminifera to oxygen availability. In sediments that range from oxic to dysoxic to anoxic to sulfidic, three foraminiferal species will be investigated. Initially, a single-cell genomic analysis will reveal their physiological and metabolic potential. Identifying the metabolic functions encoded within the genome will enable predictions regarding their physiological response to changing molecular oxygen conditions, and allow for comparisons of the metabolic potential between these different ecotypes. Subsequent experimental conditions will specifically test and validate the genome-enabled predictions of the adaptations to changing oxygen concentrations. Integrating the genomic data with physiological and chemical measurements, models will be constructed to represent the metabolic activities of the holobionts under different oxygen regimes and geochemistry. These models will elucidate the metabolic mechanisms that contribute to the adaptation of foraminifera under aerated, dysoxic, anoxic, and euxinic conditions, and the predicted changes in key C, N, O, and S metabolic pathways will be further evaluated using qPCR analyses and physiological assays. Hypotheses will be addressed with these objectives: 1) Determine the physiological and metabolic potential of foraminifera under different oxygen regimes; 2) Identify the metabolic responses of each species incubated under different oxygen regimes, following periodic and extended exposure, and; 3) Define the impact of oxidative stress and ROS production on the health and physiology of the different foraminifera under different oxygen regimes.