Aquatic Sciences Meeting, Albuquerque 2001

SS21 Ultraviolet Radiation and the Aquatic Biota (Disciplinary Connections)

Date: Wednesday, February 14, 2001, Time: 2:15:00 PM

Location: Galisteo

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

Neale, P, J, Smithsonian Environmental Research Center, Edgwater, MD, USA, neale@serc.si.edu

Grad, G, , Lehigh University, Bethlehem, PA, USA, gad2@lehigh.edu

De Lange, H, J, Lehigh University, Bethlehem, PA, USA, Marieke.deLange@Aqec.WKAO.WAU.NL

Hargreaves, B, R, Lehigh University, Bethlehem, PA, USA, brh0@lehigh.edu

BENEFICIAL AND DETRIMENTAL EFFECTS OF UV RADIATION ON AQUATIC ORGANISMS

Solar UV radiation (UVR) can have both positive and negative effects on living organisms depending on its intensity and spectral composition. We examined the beneficial as well as detrimental effects of UVR on Daphnia pulicaria, and report the first biological weighting function for a freshwater cladoceran. Although the shortest UV-B wavelengths are potentially the most damaging per photon, the greater intensity of longer wavelength UVR in sunlight causes the net potential damage to Daphnia in nature to be greatest in the longer wavelength UV-B and shorter wavelength UV-A (305-322 nm). For natural sunlight, UV-B (less than 320 nm) accounted for 64% of the mortality response while short wavelength UV-A accounted for 36%. Simultaneous exposure to longer wavelength UV-A and blue light in addition to damaging UV-B dramatically increased survival due to the stimulation of photoenzymatic repair. Data are also presented on the importance of both ozone and dissolved organic carbon (DOC) in creating strong environmental gradients in the intensity and spectral composition of solar UVR in the aquatic environment.

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Aquatic Sciences Meeting, Albuquerque 2001

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