Patrick Hassett, Ph.D.
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Visting Faculty, Ohio University
Environmental Stress Biology
A.B., Harvard University, Biology, 1976
M.S., University of Washington, Oceanography, 1982
Ph.D., University of Washington, Oceanography, 1986
Assistant Professor of Biological Sciences
Ohio University
Many invertebrates, including arthropods, are unable to biosynthesize the cholesterol that is needed for membrane function and instead must acquire cholesterol, or related phytosterols, from their diet. Since phytosterols in phytoplankton vary widely in both composition and concentration, copepods potentially could find their growth limited by the sterols in their diet. In fact, we have found that egg production and egg viability of copepods can be enhanced by supplementing a diatom diet with cholesterol. We have further found that copepods maintain a constant cholesterol content in their plasma membranes despite variation in their diet. Future research will investigate the effects of temperature acclimation on this response, as cholesterol is important in maintaining membrane function during thermal acclimation.
The role of sterols in the nutritional ecology of marine copepods
Dr. Hassett’s research at MDIBL has focused on the physiological ecology of marine copepods, small (1-3mm) crustaceans that are a critical component of marine food webs. A current area of research is the role of sterols in copepod nutritional ecology and the effects of temperature and salinity on the cholesterol content of copepods. Copepods are unable to biosynthesize cholesterol and must obtain it, or phytosterol precursors, from their diet, rendering them susceptible to growth limitation by inadequate sterol content in their diet. Varying temperature and salinity environments may create additional demands as cholesterol content is altered with acclimation conditions. In addition, unusual sterols present in some phytoplankton species may interfere with metabolic processes in copepods. Dr. Hassett’s research encompasses a range of levels of biological organization (from ecosystem dynamics to biochemical processes), and therefore it is particularly well-suited for student participation. Students will be involved in field collections of animals, laboratory acclimation experiments, and biochemical analyses.