The overall goal of this 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. The investigators hypothesize that three main population centers in the North Atlantic are quasi-distinct and selfsustaining. This hypothesis will be tested with combined physical-biological modeling and genetic analysis of C. finmarchicus populations. The 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.
The intellectual merit of this effort includes its interdisciplinary approach (physics and biology) and integrated analysis (adjoint modeling and molecular population genetics), which can provide new insights into complex oceanographic phenomena, such as ocean basin-scale processes, that are difficult or impossible to observe directly. Broader impacts of the proposed research will include international collaboration, as well as training of both undergraduate and graduate students. The project will use the outreach capacity of the "Census of the Marine Zooplankton," a Census of Marine Life (CoML) field project led by A. Bucklin, to ensure broad dissemination of results to researchers, students, and educators. This project will produce a video, contribute to CoML synthesis publications, and produce researcher interviews for the CoML web site.
