The Varying Effects of Temperature and Viscosity on the Kinematics of Three Congener Species of Marine, Carnivorous Copepods

Copepods live at the interface between viscous and inertia-dominated realms meaning that even slight changes in the fluid dynamics around them can alter the detection of prey, predators, and mates. Euchaeta is a genus of marine, carnivorous copepods that can be found in all oceans of the world but vary greatly in size. In particular, E. rimana from Hawaii, E. norvegica from Maine, and E. antarctica from Antarctica have prosome lengths of 2.12 mm, 4.86 mm, and 6.19 mm respectively. Evolved size differences are assumed to be from metabolic mechanisms adapting to thermal differences in their environment, but viscosity may play a role in shaping appendage motion and swimming speed adaptations at intermediate Reynolds numbers. As increasing temperatures have decreasing viscosities, this study investigated the independent effects of temperature and viscosity Euchaeta escape responses by using polyvinylpyrrolidone to increase seawater viscosity while the temperature, and corresponding metabolic processes, remained constant. For the smallest species, E. rimana, increases in temperature led to increases in escape responses, but so do increases in viscosity at the same temperature showing that viscosity may be an evolutionary driver for copepods at lower Reynolds numbers. The larger two species, E. norvegica and E. antarctica, did not show escape response speed dependence on temperature nor viscosity, instead exhibiting high adaptability to changing water parameters.

Presentation Preference: Oral

Primary Presenter: Cassandra DeBlois, Rhode Island College (cdeblois_7355@email.ric.edu)

Authors:

Maura Niemisto, Bigelow Laboratory for Ocean Sciences  (mniemisto@bigelow.org)

Zachary Wagner, Bigelow Laboratory for Ocean Sciences  (zwagner@bigelow.org)

Mitchell Ford, Providence College  (mitchell.ford@okstate.edu)

Arvind Santhanakrishnan, Oklahoma State University  (askrish@okstate.edu)

Jeannette Yen, Georgia Institute of Technology  (jeannette.yen@biosci.gatech.edu)

David Fields, Bigelow Laboratory for Ocean Sciences  (dfields@bigelow.org)