Collaborative Research: Field and Modeling Studies in Support of Understanding Disease Resistance in Estuarine Populations and Response to Climate Change

点击翻译按钮获取中文摘要

Host-parasite interactions in marine ecosystems are poorly studied compared to those in terrestrial systems. Many commercially exploited bivalve species experience parasitic diseases, and understanding host-parasite responses to climate change has implications for management of these fisheries. A team from Old Dominion University and Rutgers University will investigate host-parasite relationships in the eastern oyster (Crassostrea virginica), which suffers from two lethal protozoan diseases, MSX and Dermo. The team will integrate a wealth of long-term data on environmental fluctuation in Delaware Bay, the structure of its oyster population and two lethal parasites into coupled biological and oceanographic numerical models to predict how climate change may affect the host-parasite relationship. The result will be improved understanding how host genetics and population dynamics, and environment interact with disease organisms to structure host populations, and how climate change may affect these inter-related processes. They will focus on: 1) the role of disease refugia, 2) the effect of variability in the number of parents (disease-resistant or not) that reproduce offspring each year, 3) the role of environmentally-modulated selection and transmission processes in producing genetic changes in the host population, and 4) the response of the oyster-parasite interaction to climate change and consequent effects on overall host population genetic structure. Using laboratory and field studies, they will identify additional genes linked to MSX and Dermo disease resistance, and identify possible phenotypic and genotypic differences between oysters from putative refugia and high-disease areas. In addition, they will determine whether disease refugia exist because of low transmission rates or because environment inhibits infection development. Finally, they will assess spatial and temporal variability in the effective size of the spawning populations and whether "sweepstakes" reproductive events occur in oyster populations. The data from these studies will underpin models that include explicit genetic structure, disease processes, and oyster population dynamics. A circulation-biogeochemical model will provide environmental conditions for the oyster models, and allow testing of the effects of parasite and larval transport, and current and future climate conditions on host population structure. The broader impacts of the project include improved understanding of how diseases structure populations of a commercially important estuarine species. This project will also contribute to training of students in the variety of disciplines (genetics, pathology, genomics, bioinformatics, population modeling) needed to solve many of the important problems facing fisheries. Results from this project will be disseminated through scientific conferences, publication in the peer reviewed literature and web sites, and through ongoing outreach efforts to enhance general science education at local schools.