Extreme climates, extreme habitats: a paleoecological study in Lake EL Sello (-46.9234º, -71.3374º), the volcanic Buenos Aires Plateau, southern Patagonia

MASSAFERRO, J.; AMEZCUA, M.; MAYR, C.; CHARQUEÑO-CELIS, F.; UNTERMANN, F.; PÉREZ, A.; PORCEL, S.; LANCELOTTI, J.

San Carlos de Bariloche

Encuentro; Lakes as Memories of the Landscape; 2022

Universidad Nacional de la Patagonia --CONICET

The Buenos Aires Plateau (Santa Cruz, Argentina) is a bed of alkaline basalt formed duringtectonic episodes in the Miocene-Pliocene periods. It covers an area of 3650 km2 holdingmore than 150 endorheic shallow lakes, highly exposed to the westerlies winds. Duringthe last years, several lakes have suffered substantial water level reduction with negativeconsequences on the aquatic communities. Example of this is the shallow lake El Sello(-46.9234º, -71.3374º, 1466 m asl), the largest lake of this plateau. In the last 38 years, itwas 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 lakeaimed 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. Atthe moment, the remains bioproxies recovered were ephippias, cladocerans (Chydorus),testate amoebas (Diffulgia oblonga), chironomids (Cricotopus) and oogoniums (Chara). Thisis 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 conditionsof the area which let integrate with environment and climatic events in Patagonia.