congresos y reuniones científicas
Elemental stoichiometry in calanoid copepods of lakes and ponds from Patagonia
CECILIA LASPOUMADERES; BEATRIZ MODENUTTI; MARÍA SOL SOUZA; ESTEBAN BALSEIRO
San Carlos de Bariloche
Congreso; VI Southern Connection Congress; 2010
Energy and nutrient transfer may be limited by the specific needs of each organism, affecting the element availability for higher trophic levels. Consumers are frequently affected by the elemental availability on their food. Thus, omnivorous feeding provides alternative pathways for obtaining a nutritionally balanced ration, hence increasing the acquisition of the limiting nutrient through a diverse resource. Parabroteas and Boeckella are gondwanic calanoid copepods inhabitants of lakes and ponds in Patagonia. These copepods have diverse trophic strategies including omnivory, herbivory and predation. Our main goal was to study if these copepods present a differential homeostatic regulation according to their trophic strategy. We carried out a field survey in different lakes and ponds and a field experiment in order to test interactive effects of light and nutrients on copepod stoichiometry. Results showed that the elemental C:N ratio did not vary significantly between species, whereas C:P ratio did. Herbivorous copepods were strictly homeostatic along the life cycle, while predators were observed to be non strictly homeostatic both in N and P. Our experimental data showed that light and nutrient interact in the final result of copepod body elemental composition, affecting copepod response to environmental stress.