Impact of human activities and climate on Lake Morenito, Northern Patagonia, Argentina

MAUAD, MELINA; MAYR, CHRISTOPH; GRAßL, TERESA; DUBOIS, NATHALIE; SERRA, MARIA NOEL; MASSAFERRO, JULIETA

HYDROBIOLOGIA

SPRINGER

Lugar: Berlin; Año: 2019

0018-8158

Lake Morenito located in the ArgentineanPatagonia has been exposed to climatic, volcanic, andanthropogenic impacts for the last decades. In partic-ular, the damming of the lake and the eruption of theCalbuco/Puyehue Volcanoes in AD 1960 played animportant role in the lake?s history. A 80-cm-longsediment core from Lake Morenito spanning morethan 100 years was studied for chironomids, stable iso-topes, and organic geochemistry to investigate hownatural and anthropogenic stressors impacted the lake.Chironomid assemblages display large changesaround AD 1950, with the appearance of the warm-adaptedChironomusand the replacement ofApsec-trotanypusbyAblabesmyia, indicating a shift towarmer conditions. By that time and up to the present,an increasing trend ofd15N coupled with a decrease ofd13C points to shifts in the carbon and nitrogen cyclesassociated with human activities. It is evident that theonset of human activities during the 1950s followingby the lake damming in AD 1960 had significanteffects on the chironomid assemblages and the geo-chemical composition of sediments which is reflectedin the progressive deterioration of the lake ecosystem.