Consequences of glacier retreat on the trophic ecology of filter feeders and bentho-pelagic coupling in an Antarctic coastal ecosystem

GASTÓN ALURRALDE; VERÓNICA L. FUENTES; JUANCHO MOVILLA; ALEJANDRO OLARIAGA; COVADONGA OREJAS; IRENE SCHLOSS; MARCOS TATIÁN

Barcelona

Simposio; XIth SCAR Biology Symposium; 2013

Deep changes has been registered in the structure of macrobenthic and planktonic communities inhabiting Potter Cove (King George Island, South Shetland Islands), related to the retreatment of the Fourcade Glacier. The input of melting water leads to an increment in suspended particulate material, mainly inorganic, into the marine environment, which causes alterations in the filtration and respiration rates of filter feeders. Moreover, increases in the inorganic fraction could limiting the intake of organic particles reducing the assimilation effectiveness of the filtering organisms and even produce high mortality levels. Aiming to understand the energy flow between the pelagic and benthic system in Potter Cove, the trophic ecology of filtering species has been assessed under the ECLIPSE project, during the last 2013 Antarctic summer campaign. The feces´s production rate, assimilation efficiency, biodeposition rate and seston depletion rate of the Antarctic krill (Euphausia superba) and a sea squirt (Cnemidocarpa verrucosa), both considered key for benthic-pelagic coupling and food webs, were studied under different diets and sediment concentrations. In this contribution preliminary results of this work and the first conclusions obtained are communicated.