Coastal Ecosystem Responses to Global Warming: a Small-Scale Case at Potter Cove

RICARDO SAHADE; DORIS ABELE; SOLEDAD ACOSTA; CARLA DE ARANZAMENDI; MILAGROS DEMARCHI; D DEREGIBUS; VERÓNICA FUENTES; M GRAEVE; CRISTIAN LAGGER; GUILLERMO MERCURI; FERNANDO MOMO; L QUARTINO; E RODRIGUEZ; IRENE SCHLOSS; NATALIA SERVETTO; SOLEDAD TARANTELLI; MARCOS TATIÁN; LUCIANA TORRE; PAULA WIERNES; N ZAMBONI

Buenos Aires

Congreso; Scientific Committee on Antarctic Research (SCAR) Meeting; 2010

Glacier retreatment registered consistently along the Antarctic Peninsula, caused by its rapid warming, is affecting coastal ecosystems by increased ice calving, sedimentation rates and fresh water input. Factors that together with water temperature increase can severely impact on Antarctic biota. This retreating process also opened newly ice free areas available for colonization and establishment of benthic communities. Potter Cove presents an excellent opportunity to assess the effects of these processes on coastal ecosystems, due to long-term data availability and the high retreatment experienced by Fourcade glacier surrounding the cove. Mayor ecosystem shifts were observed, typical Antarctic epibenthic filter feeders communities with complex 3rd dimensional structures are being replaced by infaunal and flat forms of suspensivorous together with other functional groups as predators, scavengers and necrophagous.  It is hypothesized that this shift is mainly driven by the increased sediment input carried by glacier discharge. Sediment load in the water column, is one of the factors that showed the more significant change in the last 20 years. Differential species tolerance to inorganic matter and mathematical models, support this idea. However, in newly ice free areas were observed dense and abundant communities dominated by those species that are in rapid decline in “old” areas of the cove. Were these “new” communities developed in such a short time? Or, were they already established under the glacier in ice pockets and refugia? Will they experience a similar process to that observed in the “old” ones? Global warming is definitively affecting Antarctic coastal ecosystems, pointing to the necessity of increase our understanding on the functionality of these ecosystems and their potential responses.