Influence of Ultraviolet Radiation on UVR-Absorbing Compounds in Freshwater Algal Biofilms and Scenedesmus vacuolatus Cultures

• Published in: Journal of Toxicology and Environmental Health, Part A Vol. 70; no. 9; pp. 760 - 767
• Main Authors: Navarro, E., Robinson, C. T., Wagner, B., Behra, R.
• Format: Journal Article
• Language: English
• Published: England Taylor & Francis Group 01.05.2007
• Subjects: Biofilms - radiation effects; Dose-Response Relationship, Radiation; Eukaryota - radiation effects; Fresh Water; Photosynthesis - radiation effects; Scenedesmus - radiation effects; Scenedesmus vacuolatus; Ultraviolet Rays - adverse effects
• ISSN: 1528-7394; 1087-2620
• DOI: 10.1080/15287390701236454

There is considerable concern about increasing levels of solar ultraviolet radiation (UVR) and the potential harmful effects of UVR on living organisms. Microcosm studies were conducted with algal biofilms and Scenedesmus vacuolatus cultures to examine the effects of increased UVR on freshwater algae. Because algae have evolved various strategies to minimize the potential damage induced by UVR, the sensitivity of an UVR ratio was evaluated using absorbance characteristics of algal extracts to short- and long-term responses of algae to UVR exposure. The effects of UVR on the photosnthetic activity of periphyton also were determined by fluorometry. Results showed various patterns: (1) a short-term decrease in the UVR ratio between UVR-absorbing compounds and chlorophyll-a that reflect damage from UVR, and (2) a long-term increase in the UVR ratio as communities change their photosystems by increasing UVR absorbance capabilities, and thereby cell protection. Results include (1) validation of the UVR ratio, (2) allowing assessment of different UVR exposure-induced effects to algae, and (3) providing mechanistic information on cellular strategies used by algae to reduce UVR-induced damages.