Project: U.S. GLOBEC Pan-Regional Synthesis: Climate Forcing of Calanus finmarchicus Populations of the North Atlantic

Our overall goal for this Collaborative project is to understand the processes that regulate the large-scale distribution and abundance of Calanus finmarchicus, a keystone species of the North Atlantic ecosystem. We hypothesize that three main population centers in the North Atlantic are quasi-distinct and self-sustaining. This hypothesis will be tested with combined physical-biological modeling and genetic analysis of C. finmarchicus populations. Our modeling approach is to assimilate observations of C. finmarchicus from the Continuous Plankton Recorder (CPR) into the North Atlantic Regional Ocean Modeling System using the adjoint method.

The first phase of the project will be to investigate the mean seasonal cycle based on monthly mean CPR data together with the climatological mean circulation. The inverse model solution will be diagnosed to quantify the interconnectivity between the three population centers. Molecular population genetic analysis will yield independent estimates of the rates of exchange between the gyres, which will be compared with model predictions. This assessment of the climatological mean seasonal cycle will set the stage for a study of interannual variability, with particular emphasis on changes in the mean state of the system in association with the North Atlantic Oscillation.