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.
