OCE-PRF: Effects of increasing temperature and ultraviolet radiation on copepod mitochondria along a latitudinal gradient

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This award is funded in whole or in part under the American Rescue Plan Act of 2021 (Public Law 117-2).Our understanding of the mechanisms by which organisms respond to climate change is incomplete. As temperature and ultraviolet (UV) radiation increase, the ability of organisms to survive and reproduce depends on their ability to adapt to changes in the environment. The ability of mitochondria to produce energy in animals is influenced by the movements (i.e., behavior) and structure of these organelles. The ability of mitochondria to produce energy directly impacts animal performance, including survival and reproduction. In turn, the behavior and structure of mitochondria are influenced by the environment. This work aims to: 1) determine if UV radiation influences mitochondrial behavior and structure in natural populations of a marine organism, copepods, in the same manner observed in a laboratory setting, 2) determine if temperature affects mitochondrial behavior and structure in natural populations of copepods, and 3) determine how much the behavior and structure of mitochondria change in the short-term versus the long-term in response to changing environmental conditions. The results of this study will transform our understanding of how environmentally important organisms such as copepods may respond to climate change. In collaboration with the Auburn University College of Science and Mathematics, this work will advance the education and science literacy of students in the state of Alabama. The PI will develop several outreach programs to fit the pre-existing infrastructure at Auburn University to increase the science involvement and literacy for 1st – 6th and 11th – 12th grade students and interact with the community to discuss the importance and relevance of the research for the general public. These outreach initiatives will involve hands-on participation of students in learning about the scientific process, mitochondria, copepods, and the use of microscopes in scientific research. The general public will gain insight into the importance of the research in understanding the impact of climate change on one of our world’s most abundant aquatic organisms. The goal of this work is to integrate observational fieldwork and experimental lab work to further understand the impact of environmental stressors on the physiological ecology of copepods along the west coast of North America. This work aims to fundamentally change our understanding of the mechanisms by which pervasive zooplankton such as copepods can potentially respond to climate change. The PI will collect data on copepods from populations in San Diego, CA, Battle Rock, OR, and Friday Harbor, WA. He will measure their metabolic rate at the point of highest UV exposure and temperature during the day and lowest UV exposure and temperature at night. After measuring metabolic rate, the same copepods will be fixed for transmission electron microscopy (TEM) to quantify mitochondrial behavior and morphology, including density of the inner mitochondrial membrane, proportion of inter-mitochondrial junctions, mitochondrial density, and mitochondrial area and aspect ratio. Additional copepods from these populations will be shipped to Auburn University to establish lab populations under the same temperatures and UV radiation as measured in the field. Mitochondrial phenotypes quantified via TEM and metabolic rate will be measured following reciprocal transplant experiments in the lab to determine the extent that differences in mitochondrial phenotype are due to environmental variation versus evolved, genetic differences in response to temperature and UV radiation. In collaboration with Oregon State University, transcriptomics will be completed under the transplant experiments to identify the up/downregulation of genes that may be associated with mitochondrial behavior and morphology to maintain metabolic rate differently between the three populations. Copepods are a cornerstone of biological diversity in aquatic ecosystems. As such, it is imperative that we begin to understand the physiological responses of these organisms so that we may better understand the impact of climate change on marine populations.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.