Calanus Finmarchicus in Icelandic Waters: Population Genetics and Ecology at the Norwegian Sea/N. Atlantic Ocean Boundary

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Large-scale circulation patterns in the N. Atlantic may partition the ocean basin into three semi-distinct gyre systems: the Norwegian Sea, the northern N. Atlantic, and the western N. Atlantic. Zooplankton entrained in these gyres may be ecologically, reproductively, and (perhaps) genetically distinct due to geographic isolation in different circulation systems and/or to isolation by distance. Previous studies have demonstrated that populations of the copepod Calanus finmarchicus in the eastern and western N. Atlantic differ significantly in haplotype frequencies of the mitochondrial 16S rRNA. This project will provide a further examination of ocean basin-scale genetic structuring of C. finmarchicus, and especially examination of the boundary between the N. Atlantic and the Norwegian Sea, through collaboration with Icelandic oceanographers. Field collections will be made in waters surrounding Iceland, which lies at the boundary between the gyres of the N. Atlantic Ocean and the Norwegian Sea, during the annual Marine Research Institute Spring Survey in May/June, 2000. Calanus finmarchicus will be identified and removed from selected samples at the MRI in Reykjavik, Iceland, and shipped to the University of New Hampshire for molecular analysis. Three different gene portions will be evaluated as population genetic characters for the examination of ocean-basin scale population structure and the differentiation of gyre populations: the mitochondrial cytochrome oxidase I (COI); the nuclear gene encoding phosphoglucose isomerase (PGI), including both coding regions and introns; and a putative nuclear pseudogene of COL Molecular variation will be evaluated by direct DNA sequencing and possibly by the rapid and less expensive assay, Single-Stranded Conformational Polymorphism. (SSCP), which can detect variability of the amplified DNA and confirm allelic identities. A suite of population genetic and statistical tests will be used to quantify the genetic distinctiveness of populations and characterize population genetic structuring at the targeted scales. The distribution, abundance, and genetic variation of C. finmarchicus will be placed in a realistic ocean setting, including water mass structure and ocean circulation patterns, using contour mapping and data visualization.