Collaborative Research: ORCC: Carryover effects of multiple climate change stressors in oysters: mechanisms and consequences across stages of ontogeny

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Climate change is exposing species to multiple stressors that affect their ability to grow, reproduce, and provide ecosystem services that benefit humans. However, repeated exposure to the same stressors over an organism’s lifetime may allow some species to acclimate and avoid these negative effects, especially if the initial exposure occurs when an individual is young. This study uses oysters to experimentally test how early life exposure to ocean warming and low dissolved oxygen affects oysters’ responses to these same stressors later in life. The eastern oyster is an economically important species that provides ecosystem services to humans such as reducing nitrogen loading to coastal systems and protecting shorelines from storms. But oyster survival and growth are negatively affected by declining dissolved oxygen caused by high nutrient runoff from land and rising atmospheric carbon dioxide and temperature. The findings will improve our understanding of how repeated stress exposure affects species’ responses to climate change, and whether repeated exposure is a tool that can be harnessed to improve food and job security in aquaculture and resource management. This potential strategy will be shared with aquaculture stakeholders throughout Maryland in a series of workshops. It will engage graduate students and undergraduates in scientific research. It will also introduce elementary through high school students to the concepts of climate change and the importance of marine ecosystems to human well-being through the development and distribution of Science-to-Go modules that provide at-home science activity kits on topics related to the project.Phenotypic plasticity is an important component of organismal responses to climate change, but is typically examined only in relation to an individual’s current environment. However, organism phenotypes are frequently influenced by past environmental experiences such as those that occur early in life, but little is known about how these “within-generation carryover effects,” or the mechanisms that drive them, persist and change across organism ontogeny. The proposed research will explore how early life exposure to two interacting climate change stressors – hypoxia and warming – impacts eastern oyster (Crassostrea virginica) fitness as well as the potential mechanisms and ecological consequences of these carryover effects across multiple years and at multiple points during ontogeny. This study involves a series of manipulative experiments in the lab and field (on an aquaculture farm) and analyzes oyster fitness, microbiomes, methylomes, and nitrogen content at each ontogenetic stage. The need to understand plasticity through time and the lasting influence of past environments on organism traits is critical to accurately predict organismal responses to climate change. Because climate change is increasing the likelihood that organisms will be exposed to the same stressors repeatedly over their lifetimes, within-generation carryover effects may play an increasingly important role in adaptive responses. Carryover effects may be a means of quickly acclimating organisms to future environments that can be used in conjunction with selective breeding to create more resilient organisms. This research will thus generate data on a potential strategy for addressing effects of climate change on aquaculture and coastal 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.