Extreme climates, extreme habitats: a paleoecological study in Lake El Sello, the volcanic Buenos Aires Plateau, southern Patagonia

PEREZ, ALEJANDRA PATRICIA; MASSAFERRO, JULIETA; CHARQUEÑO CELIS, FERNANDA; PORCEL, SOL; MONTSERRAT, AMEZCUA VARGAS; FEDERICA, UNTERMANN; LANCELOTTI, JULIO; MAYR, CRISTOPH

San Carlos de Bariloche

Congreso; IPA-IAL 2022 Lagos Memorias del Territorio; 2022

The Buenos Aires Plateau (Santa Cruz, Argentina) is a bed of alkaline basalt formed during tectonic episodes in the Miocene-Pliocene periods. It covers an area of 3650 km2 holding more than 150 endorheic shallow lakes, highly exposed to the westerlies winds. During the last years, several lakes have suffered substantial water level reduction with negative consequences on the aquatic communities. Example of this is the shallow lake El Sello (-46.9234º, -71.3374º, 1466m asl), the largest lake of this plateau. In the last 38 years, it was observed a reduction of the area lake by 52%, associated with the decrease in rainfall. We present preliminary data obtained from analyzing a 50 cm sediment core of El Sello lake aimed to make the first inferences on the recent past environmental conditions in the area. From the core analysis we detected 5 tephra levels (1, 8, 23-27, 43 cm) along the core. At the moment, the remains bioproxies recovered were ephippias, cladocerans (Chydorus), testate amoebas (Diffulgia oblonga), chironomids (Cricotopus) and oogoniums (Chara). This is a first attempt to develop a palaeoecological study in these basaltic patagonian plateaux. We expect to find changes in the biota assemblage related to the extreme climate conditions of the area which let integrate with environment and climatic events in Patagonia