Ecophysiology of gelatinous
 organisms in hypoxia

Erik V. Thuesen, Ph.D.
The Evergreen State College

Wednesday, October 10, 2001
3:00 p.m.–Pacific Forum

Several species of ecologically important gelatinous zooplankton in southern Puget Sound and Chesapeake Bay have been examined in order to estimate the effects of low oxygen. The study focused on the oxygen regulatory abilities of the zooplankton and their ability to tolerate anoxic conditions. The study included ctenophores, scyphomedusae, hyromedusae, and siphonophores.

The mean oxygen consumption rate, minimum partial pressure to which the organism can regulate oxygen consumption (Pc), and the ability of each species to withstand anoxia have been measured. Results show that several species can oxyregulate at less than 10% oxygen saturation and survive complete anoxia for several hours. The oxygen concentration in the gel has been measured, and it appears that the gel facilitates oxygen diffusion. These results indicate that gelatinous organisms are better at tolerating poor oxgyen conditions than many of their pelagic competitors and prey.