Dr. Franco Salerno and a team of Italian researchers conducted long-term field work in the Himalayan area, discovering a dramatic increase of ionic concentrations in glacial lakes. This increase may lead to some large and irreversible environmental effects, according to Salerno et al. A report detailing their findings was published in the journal of Environmental Science & Technology in July.
Over the past two decades, Dr. Salerno and his team have observed a significant rise in ionic content in a total of 20 remote high-altitude glacial lakes located in central southern Himalaya. When asked by GlacierHub about why his team conducted their research in the Himalayan region, Dr. Salerno said, “The Italians have a long experience and passion for the high mountains. The culture and the capacity to climb is probably born around the Alps, and also drove us to study the Himalayan glaciers.”
The group had to overcome many difficulties to perform their research including low temperatures, language barriers, and even snowblindness. But thanks to help from the local people, they managed to finish their research. The scientists also received support from the Ev-K2-CNR Association and the Italian National Research Council (CNR) to conduct studies in the Hindu Kush – Karakorum – Himalaya region and the countries of Nepal, Pakistan, China (Tibetan Autonomous Region) and India.
Among their findings, the team detected a substantial rise of in-lake chemistry determined mainly by the sulfate concentration. LCN9, one of the 20 lakes monitored on an annual basis for the last 20 years, was found to have sulfate concentrations that increased by over 4-fold over that time period. In this region, the researchers also observed a significant relationship between the increase in the annual temperature recorded in the area and the enhanced conductivity in two glacial lakes.
After examining several factors, including temperature, precipitation, rocks and soil weathering processes, and seasonal snow cover duration, they concluded that glacier retreat likely was the main factor responsible for the observed increase of sulfate concentrations. Moreover, the weakened monsoon of the past two decades has partially contributed to the lakes’ enrichment through runoff waters that are concentrated in solutes and by lowering the water table, resulting in more rock exposed to air and enhanced mineral oxidation.
The higher mineral contents have not threatened the ecosystems, but high mountain ecosystems can be especially vulnerable to climate change. The change may lead to some negative outcomes not yet foreseen. Research in other areas including the Florida Everglades, California Limekiln Creek and Vestfold Hills have shown the negative impacts of increased sulfate concentrations on lake ecosystems. By the same token, a notable increase of ionic concentrations may lead to irreversible changes to the fragile local ecosystem, biodiversity in the lakes or even human health.
As Dr. Salerno commented, “We think that the glacier masses in this region are decreasing as coupled effect of the global warming and the weakness of the monsoon. Even if these changes do not pose a direct and immediate threat to the ecosystem, they occurred in a limited time span and significantly modified the average chemical composition of lake water, which will cause some potential changes in the future.”