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

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

Perth, Scotland, UK

Congreso; Global Change and the World’s Mountains; 2010

Calanoid copepods are dominant zooplankters in many nutrient poor mountainlakes. In these ecosystems, high C:P ratios are associated with high lightphosphorusratios, thus, organisms living in these transparent lakes would beconstrained by potentially hazardous ultraviolet radiation (UVR). In AndeanNorth Patagonian lakes, the success of the widespread calanoid copepodBoeckella gracilipes would relay in intraespecific differences in photoprotectivepigments (carotenoids and mycosporine-like amino acids), elemental ratios(C:N:P) and in antioxidant enzyme activities. We carried out experiments totest how C:P ratios and photoprotective pigments combine to enhanceprotection to UVR. We hypothesize that while carotenoids and MAAs creates adirect protection, C:P ratio would affect the antioxidant capacity and henceprotection against damage in acetylcholinesterase (AChE). Althoughcarotenoid concentration was higher in organisms inhabiting fishless highaltitude lakes, the antioxidant enzyme glutathione-S-transferase (GST) activitywas also higher in these copepods than in low altitude with higher sestonic C:Pratios. Changes in solar radiation as well as in elemental ratios will affectcellular mechanisms that will have important consequences in organisms suchas movement capacity.