Meeting Abstract
Marine communities face continuing and accelerating climate change; however, we are still far from being able to predict which species will go extinct and which will persist in future climates. To make these predictions, we need to understand the efficacy of mechanisms that allow species to persist in altered environmental conditions, including poleward range shifts of tolerant individuals. Shifts in distributions and the frequency of stress-resistant phenotypes may be particularly challenging for sessile marine species inhabiting regions where currents flow in the opposite direction of climate shifts, including along the northeast and northwest coasts of the USA. We developed an integrative approach to, first, estimate the proportion of individuals in cohorts of recruiting marine invertebrates (mussels in the genus Mytilus) that originated from northern versus southern sources. Estimates based on both shell geochemistry and oceanographic modeling indicated that individuals are able to disperse “against the flow” towards relatively cooler latitudes. We then collected intensive time-series observations of thermal tolerances for recruiting mussel larvae, finding that cohorts are phenotypically differentiated across time, possibly due to local adaptation in parent populations or selection during dispersal. These results highlight the important interplay between two natural climate-change coping mechanisms: redistribution and physiological tolerance to changing thermal conditions.
