You are here:
Genetic structure of the benthic amphipod Diporeia (Amphipoda: Pontoporeiidae) and its relationship to abundance in Lake Superior
Citation:
Pilgrim, E. M., J. V. SCHAROLD, J. DARLING, AND JOHN R. KELLY. Genetic structure of the benthic amphipod Diporeia (Amphipoda: Pontoporeiidae) and its relationship to abundance in Lake Superior. CANADIAN JOURNAL OF FISHERIES AND AQUATIC SCIENCES. NRC Research Press, Ottawa, Canada, 66(8):1318-1327, (2009).
Impact/Purpose:
A key objective of the Clean Water Act is "to restore and maintain the chemical, physical, and biological integrity of the nation’s waters." Biological integrity is defined as the ability of an aquatic ecosystem to support and maintain a diverse, balanced, integrated, adaptive community of native organisms. A primary focus of this research effort is the molecular characterization of genetic diversity, a fundamental component of biodiversity and an important indicator of biological integrity. This research will assess and define biological integrity with scientific rigor, using population genetics as the basis for understanding biological diversity and functional organization.
Description:
The freshwater amphipod Diporeia is a crucial part of the food web in the Laurentian Great Lakes, but has faced serious declines correlated with the invasion of zebra mussels (Dreissena polymorpha), except in Lake Superior, which has seen an increase in Diporeia abundance. Speculation as to the mechanisms causing this decline has not considered the possibility of evolutionarily distinct lineages of Diporeia within the Lakes. In this study, we use COI DNA sequence data to investigate the evolutionary history of Lake Superior Diporeia relative to the other Great Lakes, and consider potential population structuring within Lake Superior based upon depth or geography. Our analyses reveal that Lake Superior Diporeia represent a distinct lineage that diverged from populations of the other lakes at least several hundred thousand years ago. F-statistics show that two localities within Lake Superior were significantly different from all other locales, but analysis of molecular variance did not find significant structure based on depth or geography. Genetic diversity within Lake Superior was not correlated with depth, although abundance was significantly negatively correlated with increasing depth.