PRESENT AND FUTURE ADAPTATION OF MARINE SPECIES ASSEMBLAGES DNA-Based Insights into Climate Change from Studies of Physiology, Genomics, and Evolution

Marine species live in a dynamic physical and biological environment that demands frequent physiological adjustment and can result in strong natural selection or shifts in species ranges. We illustrate the patterns and processes of adaptation to environmental change with genetic-based examples that range from a focus on single proteins to whole genomes to whole communities. This work shows how single amino acid changes adapt proteins to function at different temperatures. It shows how acidification impacts expression of proteins in energy pathways in adults and exerts natural selection on many genes in larvae. Whole genome surveys along coastlines are now possible, and they reveal unexpected patterns of genetic differentiation even in highly dispersive species. Genetic surveys of over 70 species along the North American west coast show high levels of genetic diversity and genetic structure clustered at headlands and capes known to mark species range boundaries. Finally, new surveys of DNA variation in whole communities show promise for rapid monitoring that can augment and complement traditional dive surveys. Overall, dynamics in the physical environment have a strong effect on organism physiology, which results in diverse patterns of population growth and persistence, as well as of species range and evolutionary capacity. The high level of adaptive genetic variation shown here suggests an ability for marine populations to adapt in the face of climate change, but many questions remain about how fast, complete, and effective this evolution will be.