Comparative red blood cell physiology: uncovering novel cellular mechanisms to predict the impacts of climate change on fishes

• Applicant: Dr. Till Harter, Ph.D.
• Subject Area: Animal Physiology and Biochemistry ; Cell Biology
• Term: since 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 527813621

Anthropogenic climate change poses an immediate threat to aquatic ecosystems around the globe, including the ecologically, culturally, and economically-important Atlantic cod populations of the North Atlantic and Arctic. The mechanisms that cause ecological change at the population and ecosystem levels are poorly understood and will be based on physiological limitations in individual animals. Thus, there is a critical need for experimental work at the cellular and molecular levels to advance our understanding of the mechanisms that drive ecological change in aquatic ecosystems. Oxygen (O2) is essential for vertebrate life and complex cardio-respiratory systems have evolved to transport the gas from the environment to every cell, and to remove metabolically produced carbon dioxide (CO2). Climate-change and environmental stressors (warming, hypoxia and hypercapnia/ocean acidification) threaten to upset homeostasis in fish by disrupting the fine balance between cardiovascular gas transport relative to the metabolic needs. Red blood cells (RBC) are the most abundant cells in vertebrates, they come in close contact with every other cell type and carry the haemoglobin and carbonic anhydrases that drive the delivery O2 and the removal of CO2 in every tissue. RBCs may play a central role in balancing cardiovascular gas transport relative to the metabolic needs, but the mechanistic link between their cellular function and organismal homeostasis is still poorly understood. The overarching goal of this research program is to study cellular and molecular mechanisms at the level of the RBC that facilitate organismal performance and have consequences at the ecosystem level. Objective 1: To characterise the phenotypic plasticity in RBC cellular physiology in response to environmental stress in Atlantic cod. Objective 2: To characterise the cellular mechanisms of O2 and acid-base sensing in cod RBCs. Objective 3: To characterise the endocrine signalling pathways of cod RBCs and their effects on downstream targets in the vasculature and tissues. Objective 4: To link adaptive variation in RBC physiology to the tolerance of Atlantic cod populations to climate change By using an integrative approach across multiple levels of biological organisation, the proposed research will improve our mechanistic understanding of how vertebrates balance cardiovascular gas transport with the metabolic demands at the tissues. The outcomes of this work may reveal novel therapeutic targets to improve health outcomes in animal and human disease. In addition, this information will be critical to understand, predict and mitigate the impacts of climate change on marine fishes, aquatic ecosystems and human economic activities that depend on them (aquaculture, fisheries, tourism). Finally, the outcomes have immediate applications in policy making and can improve the management of Atlantic cod fisheries, including the economically-important North-Eastern Arctic Cod (NEAC) stocks.

• DFG Programme: Independent Junior Research Groups