distribution of A. hudsonica in southern estuaries. Temperatures in the winter have warmed more than temperatures in the spring, changing the biologically important threshold for winter-spring species in estuaries. This is causing a population pulse of A. hudsonica to occur about 1.5-2.0 months earlier. Genetic It has been found that there are geography distinct subgroups of A. hudsonica along the west Atlantic coast. The first group is from Rhode Island/South Coast Massachusetts/Cape Cod to southern Maine, the second group is from southern Connecticut/Long Island Sound, and the third group is from southern New Jersey. It is thought that the genetic isolation of these subgroups of A. hudsonica has developed because of its geographical isolation in estuaries. This isolation might also contribute to the higher genetic variation within A. hudsonica than other Acartia species. Ecological significance Zooplankton play an important role in the pelagic food web by linking primary producers to higher trophic levels, and significantly contribute to biogeochemical cycles. A. hudsonica will feed on a variety of organisms including phytoplankton, heterotrophic protists and mixotrophic protists. The energy gained from their prey then gets transferred up the food web when the A. hudsonica themselves are eaten. A literature review done in 1984 showed that copepods, including Acartia, are the most frequently recorded prey of larval fish. And subsequent research has continued to document this trend. With the changing climate the size of estuarine copepods, such as A. hudsonica, are decreasing, which could disrupt the predator-prey interaction that commonly occurs between fish larvae (predators) and copepods (prey). If the dynamic of this interaction changes then the community structure and ecological function of estuaries could be altered. References Milligan, P. J., Stahl, E. A., Schizas, N. V., & Turner, J. T. (2010). Phylogeography of the copepod Acartia hudsonica in estuaries of the northeastern United States. Hydrobiologia, 666(1), 155–165. Bradford, J. M., 1976. Partial revision of the Acartia subgenus Acartiura (Copepoda: Calanoida: Acartiidae). New Zealand Journal of Marine and Freshwater Research 10: 159–202. Biologydictionary.net Editors. (2014). Copepod Definition, Characteristic and Lifecycle. Retrieved November 4, 2014, from Copepod: Definition, Characteristics and Lifecycle Copepod Printout - Enchanted Learning Software. (n.d.). Retrieved from Copepod Printout - Enchanted Learning Software Lee, W. Y. & B. J. McAlice, 1979. Seasonal succession and breeding cycles of three species of Acartia (Copepoda: Calanoida) in a Maine estuary. Estuaries 2: 228–235 Turner, J. T., 1994a. Planktonic copepods of Boston Harbor, Massachusetts Bay