Biotic interactions in Antarctic lakes. Research coming from the LIMNOPOLAR project in the Peninsula Byers

Abstract

Rochera, C., Villaescusa, J.A., Díazmazip, M.E., Gil-Delgado, J.A., Toro, M., Rico, E., Velázquez, D., Quesada, A., Camacho, A.(2011). Biotic interactions in Antarctic lakes. Research coming from the LIMNOPOLAR project in the Peninsula Byers. Ecosistemas 20(1):23-32

The plankton communities of Antarctic lakes show a simple trophic structure. These communities are functionality dominated by microorganisms. When zooplankters are present, they constitute usually the top predators. It is for this reason that these ecosystems results appropriate to undertake studies related with the trophic and functional ecology. Our purpose has been to validate some ecological concepts concerning trophic interactions, energy flows, and the relative role of abiotic and biotic factors as structural forces in polar ecosystems, which are submitted to a strong physical control. The experimental studies that we have performed in Byers Peninsula (Livingston Is.) put forward that some biotic interactions such predation might account for this structural role. In this sense, it can be deduced from our findings the occurrence of trophic cascades in the plankton that extends to the microbial loop. Particularly, are significant those interactions derived from the zooplankton activity. Thus, the occurrence of zooplankters induce a general increase of picoplankton abundances because the control of bacterivory. Our studies demonstrate also the capacity of this zooplankton for nutrients recycling, which is supposed to sustain inpart the productivity of the system. These observations allows to outline a conceptual model for the pelagic food web functioning. The progressive increase of temperatures in polar regions might promote the energy inputs and also activate the nutrients turnover. A direct consequence of this warming could be the increasing role of the biotic interactions referred here.