BALSEIRO esteban Gabriel
Antioxidant defences in planktonic crustaceans exposed to different underwater light irradiances in Andean lakes.
SOUZA, M.S.; MODENUTTI, B.E.; BALSEIRO, E.G.
WATER AIR AND SOIL POLLUTION
Año: 2007 vol. 183 p. 47 - 57
In freshwater environments direct biologicaleffect of ultraviolet radiation (UVR) result fromabsorption of specific wavelengths by macromoleculesand alteration of biochemical processes. Indirecteffects are related to UVR interaction with water anddissolved organic carbon to form chemically reactivespecies (ROS: reactive oxygen species). Zooplanktonphotoprotection includes mycosporine-like aminoacids, pigments, production of quenching agents andantioxidant enzymes. The relative importance of eachmechanism would depend on the organisms. In thisstudy, we determined the antioxidant enzyme activitiesCatalase (CAT) and Glutathione-S-transferase(GST) in the copepod Boeckella gracilipes and thecladoceran Ceriodaphnia dubia in three Andean lakesof the North-Patagonia region. There were differencesin antioxidant enzymes expression between copepodsand cladocerans. CAT was significantly higherin C. dubia than in B. gracilipes whereas GST wassimilar in both species. The comparison of B. gracilipesenzyme activity in the three lakes showed also differencesin GST but not in CAT. DOC decreases theexposure by absorption of UVR but simultaneouslyacts as photosensitizer producing ROS and theirsuccessive toxic products in the surface waters. Wediscuss that comparisons among lakes of differentDOC should be considered carefully because lakephysico-chemicals parameters, as well as food webstructure, will difficult any predictions on the net effectof DOC.