LTER Italy: Long term research in high altitude lakes in the Himalayas

Among the long term measurements initiative, we highlight here some results from the long term research carried out in the Himalayas on a LTER-Italy site: Lake Pyramid. The research activity were carried out in the framework of the SHARE Project (Station at High Altitudes for Research on the Environment). The main objective of SHARE is to assure a continuous environmental monitoring in mountain sites through long-term, high quality data series and contributing to the study of climate changes impacts and adaptation strategies in high mountain regions by making the obtained information available to governments and international agencies. Limnological survey (including chemistry, biology, and sediment core studies) of lakes located between ca. 4500 and 5500 m a.s.l. have been performed nearly every year from 1992 in the Khumbu Valley, Nepal. As an example, among the many possible, here we refer the research focused on the two lakes located near the Pyramid Laboratory in the Khumbu Valley. Lake water chemical surveys over the period 1992-2002 reveal a constant increase of the ionic content of the lake water probably related to glacier retreat. Analysis of the benthic fauna reveals shifts in species composition probably as a response to the recent warming. Paleolimnological reconstructions show the potential use of these sites in providing proxy data of past climatic changes displaying an alternance of warmer/wetter and cooler/drier periods. Future research activities will be needed to integrate lakes, wetland and stream habitats at a catchment scale and to focus on the key drivers of aquatic system change (nutrients, acid deposition, toxic substances) and their interaction with global drivers such as climate using time-series analysis, paleolimnology, experiments, and process modelling at different time scales (seasons/years and decades/millennia).