Impact of human activities and climate on Lake Morenito, Northern Patagonia, Argentina
Lake Morenito located in the Argentinean Patagonia has been exposed to climatic, volcanic, and anthropogenic impacts for the last decades. In particular, the damming of the lake and the eruption of the Calbuco/Puyehue Volcanoes in AD 1960 played an important role in the lake’s history. A 80-cm-long sediment core from Lake Morenito spanning more than 100 years was studied for chironomids, stable isotopes, and organic geochemistry to investigate how natural and anthropogenic stressors impacted the lake. Chironomid assemblages display large changes around AD 1950, with the appearance of the warm-adapted Chironomus and the replacement of Apsectrotanypus by Ablabesmyia, indicating a shift to warmer conditions. By that time and up to the present, an increasing trend of δ15N coupled with a decrease of δ13C points to shifts in the carbon and nitrogen cycles associated with human activities. It is evident that the onset of human activities during the 1950s following by the lake damming in AD 1960 had significant effects on the chironomid assemblages and the geochemical composition of sediments which is reflected in the progressive deterioration of the lake ecosystem.
KeywordsPaleolimnology Chironomid assemblages Organic geochemistry Human impact Patagonia
We thank Natalia Garcia Chapori and Olga Laura Liniers for helping with the fieldwork and lab sampling. This study is a contribution to the project PICT 2931 (MINCYT/Argentina) and PIP 11220110100185 (CONICET/Argentina). Fieldwork and travel grants were funded by a Cooperation Project between BMBF Germany (01DN16025) and MINCYT Argentina (AL15/03). We are grateful to Nahuel Huapi National Park for the logistic support.
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