Many animals inhabit environments in which factors such as temperature and oxygen vary on a daily basis. To match their changing environment, organisms have evolved biological rhythms that regulate the timing of many physiological processes. These rhythms are observed in almost all animals yet questions remain about how changing environmental conditions are sensed, how they perturb physiological systems, and how physiological rhythms help to offset their effect? The aim of this proposal is to use functional genomic approaches to understand how physiological processes are orchestrated in one of the most variable environments on earth, the marine intertidal. Analysis of gene expression patterns in field assemblages of the mussel, Mytilus californianus, revealed that the expression of metabolic genes is temporally separated from the expression of cell division genes. The magnitude of this pattern varies by position on the shore suggesting that physiological rhythms are driven by the prevailing environmental conditions on the shore. This proposal will investigate the environmental cues that are driving these gene expression oscillations and how they relate to physiological rhythms in mussels. Analysis of metabolite levels will test the hypothesis that expression oscillations are linked to changes in metabolic status of the mussels that in turn is affected by the prevailing environmental conditions in the field. This research will improve our understanding of the basic mechanisms that allow life to flourish in fluctuating environments and will provide insights into the potential impact of environmental alterations through climate change and pollution. The tools that will be developed in this proposal will have broad applications in other areas of environmental science for which mussels are important models for study, including pollution-monitoring, population genetics, aquaculture, and the prevention and elimination of species invasions. This research will be used as a model to teach K-12 and undergraduate students how natural and anthropogenic changes to the environment will impact the survival of marine organisms.
