Impacts of human activities and climate on Lake Morenito, Northen Patagonia, Argentina

MAUAD, MELINA; MAYR, CHRISTOPH; MASSAFERRO, JULIETA; DUBOIS, NATHALIE

Dublin

Congreso; IPA IAL Joint Meeting 2018; 2018

IPA IAL

For more than 50 years, Lake Morenito, located in the city of Bariloche in the Nahuel HuapiNational Park (Argentina), has been exposed to anthropogenic impacts including damming,house-building, species introduction, tourism, and probably climate change. An 80 cm-longsediment core spanning more than 100 years from L. Morenito was studied for chironomid larvae,stable isotopes, and organic geochemistry to resolve how natural and anthropogenic stressorsimpacted the lake. The core chronology is based on 210Pb and 137Cs activities. Chironomidassemblages display major changes around AD 1950. The appearance of the warm adaptedChironomus and the replacement of Apsectrotanypus by Ablabesmyia indicate a shift to warmerconditions. Chironomid composition changes again in AD 1960, post-damming and after thedeposition of volcanic tephra, followed by slow recovery of several taxa. At this time, a change inthe sediment accumulation took place possibly linked to increased erosion during and afterdamming. However, for most of the core, low TOC/TN values (