Intraespecific differences in the antioxidant capacity in the copepod Boeckella gracilipes of Andean lakes and consequences in metabolic enzymes.

BALSEIRO, E.G; SOUZA, M.S.; LASPOUMADERES, C.; MODENUTTI, B.E.; BASTIDAS NAVARRO, M.; CUASSOLO, F.

Congreso; Climate Change and the World Mountains; 2010

Calanoid copepods are dominant zooplankters in many nutrient poor mountain lakes. In these ecosystems, high C:P ratios are associated with high light-phosphorus ratios, thus, organisms living in these transparent lakes would be constrained by potentially hazardous ultraviolet radiation (UVR). In Andean North Patagonian lakes, the success of the widespread calanoid copepod Boeckella gracilipes would relay in intraespecific differences in photoprotective pigments (carotenoids and mycosporine-like amino acids), elemental ratios (C:N:P) and in antioxidant enzyme activities. We carried out experiments to test how C:P ratios and photoprotective pigments combine to enhance protection to UVR. We hypothesize that while carotenoids and MAAs creates a direct protection, C:P ratio would affect the antioxidant capacity and hence protection against damage in acetylcholinesterase (AChE). Although carotenoid concentration was higher in organisms inhabiting fishless high altitude lakes, the antioxidant enzyme glutathione-S-transferase (GST) activity was also higher in these copepods than in low altitude with higher sestonic C:P ratios. Changes in solar radiation as well as in elemental ratios will affect cellular mechanisms that will have important consequences in organism’s functioning such as movement capacity.