Physiological response of Antarctic solitary ascidians to increased sediment deposition

TORRE, LUCIANA; ABELE, DORIS; SERVETTO, NATALIA; LAGGER, CRISTIAN; ZAMBONI, NADIA; TARANTELLI, SOLEDAD; TATIÁN, MARCOS; MOMO, FERNANDO; SAHADE, RICARDO

Workshop; Impact of glacial melting on marine coastal systems in the Western Antarctic Peninsula region (IMCOAST); 2010

In the last 15 years the benthic community of Potter Cove have suffer important shifts in the abundance and distribution of different groups of filter feeders. The main objective of our work is to understand, how sensitive/tolerant different filter feeders are to the local change scenario in Potter Cove, to be able to model the future perspectives of the benthic community within the current climate trend. In the beginning of our investigation the focus on the consequences of hydrografic change and especially increased coastal sediment run-off on benthic filter feeders. We investigated the effect of different concentrations of natural sediment on metabolic rate (mgO2 g-1 dry mass d-1) of three ascidian species, simulating the in-situ sedimentation conditions. We also compared the metabolic capacity of the ascidians with and without sediment coverage including aerobic, (citrate synthase (CS) activity) and anaerobic capacities (lactate (LDH), opine dehydrogenases (ODH) activity), as well as their tissue energy content in terms of glycogen. We can see clear differences in the tolerance of different species to sedimentation, both functionally and metabolically founded, and are now trying to align these results with the observed shift in communities and species abundance.