Biogeographic and morphological variation in bosminid communities across the Laurentian Great Lakes

Session: Great Lakes Lower Trophic Level Community Dynamics (2)

Elizabeth Whitmore, Cornell University, [email protected]
James Watkins, Cornell University, [email protected]
Kay Van Damme, Tvärminne Zoological Station, Hanko, Finland and Senckenberg Research Institute and Museum of Nature, [email protected]
Lars Rudstam, Cornell University Bio Field Station, Dept. of Natural Resources, [email protected]

Abstract

Nearctic bosminids have been studied for their ability to adapt to changes in temperature, algal species composition, and invertebrate and fish predation. Bosminids utilize cyclomorphosis much like Daphnia in response to these changes. While these adaptations have helped bosminids adapt to environmental changes, phenotypic plasticity has made accurate taxonomic evaluations of bosminids difficult. We have compiled a biogeographical assessment of Bosmina (Bosmina) longirostris and Bosmina (Eubosmina) coregoni across the Laurentian Great Lakes for 2016, 2015, 2010, and 2005 data. We have found that some exotic species (like B. (E.)  coregoni, “coregoni”-type) may be more easily traced on morphology, others (like “longispina”-type) are more difficult to identify. The Baltic Sea form of B. (E.) coregoni, B. (E.) cf. longispina maritima was found in the Laurentian Great Lakes in 1988 through 1992. Traits previously used for taxonomy; size and presence of a mucro, rostrum length, and antennules length are plastic traits that can vary within a population. Analysis of Great lakes samples have shown that bosminids previously thought to be B. (B.) longirostris were a mix of bosminid species one of which corresponds closest to the Baltic Bosmina. B. (E.) cf. longispina maritima has now been found in all Laurentian Great Lakes.