Aquatic Sciences Meeting, Albuquerque 2001

SS21 Ultraviolet Radiation and the Aquatic Biota (Disciplinary Connections)

Date: Wednesday, February 14, 2001, Time: 2:30:00 PM

Location: Galisteo

Dee, G, , Lehigh University, Bethlehem, USA, gad2@lehigh.edu

Williamson, C, E, Lehigh Unversity, Bethlehem, USA, cew0@lehigh.edu

Karapelou, D, M, Cedar Crest College, Allentown, USA,

TEMPERATURE DEPENDENCE OF ULTRAVIOLET RADIATION DAMAGE IN ZOOPLANKTON

In nature, epilimnetic zooplankton are exposed to UV radiation at a variety of temperatures. Organisms protect themselves from UV damage through (a) photoenzymatic repair (PER), using the enzyme photolyase to reverse DNA dimers, and (b) photoprotection, using photoprotective compounds to absorb UV. Since enzyme activity is temperature dependent, we hypothesized that temperature would affect an organisms' ability to protect itself from UV. We exposed Asplanchna to four doses of UV radiation at each of four temperatures (10, 15, 20, and 25 degrees C). We found that the relative PER in Asplanchna was higher at 25 degrees than at the lower temperatures. Photoprotection was negligible at 25 degrees C and high at the lower temperatures. As UV dose increased, the relative importance of the two repair mechanisms shifted from photoprotection to photoenzymatic repair within the temperature range tested. We also found that reproductive output decreased with decreasing temperature and increasing UV dose. These findings indicate that temperature may play an important role in how organisms survive UV damage in nature.

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Aquatic Sciences Meeting, Albuquerque 2001

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