Lakes in Greenland Suffer From 'Extreme Climate' Conditions, Experts Note Decline in Water Quality and Carbon Emission
In fall 2022, West Greenland faced record heat and precipitation, which possibly caused a concerning change in the lakes of the locality. The water bodies turned brown and started releasing carbon, stated Science Direct. Researchers noted that the water quality also fell drastically after the color change. Findings regarding the alteration in these lakes have been published in the scientific journal Proceedings of the National Academy of Sciences (PNAS).
The changes that had occurred on the lakes in a matter of months typically took hundreds of years to happen, according to experts. Researchers cite the rainfall and thawing that the region experienced due to heat as primary reasons behind the altered properties. The thawing of permafrost containing organic carbon released elements like magnesium, iron, and carbon into the environment, which later entered the lakes due to rain.
This was not the first time such a phenomenon had been witnessed. Researchers compared the change to the multi-decade-long browning seen in lakes of the Northern Hemisphere. It was the pace with which the transformation happened that shocked experts. "The magnitude of this and the rate of change were unprecedented," said Jasmine Saros, Associate Director, at the University of Maine Climate Change Institute.
The influx of organic carbon and other nutrients from the permafrost encourages bacterial growth in the waterbody, researchers stated. They cause a significant change in properties like taste, odor, and color. Experts further claimed that the metal exposure in the lake can cause health issues for individuals drinking its waters. "The increased dissolved organic material can interact with drinking water treatment processes to produce chlorination byproducts called trihalomethanes, which may be carcinogenic," Saros explained.
Before the drastic change, these lakes sequestered carbon dioxide, a greenhouse gas in the summer. Now they have become a source of it, leading to a 350% increase of this greenhouse gas in the atmosphere. Researchers believe this is because of the decreased biodiversity of plankton. The population of phytoplankton that absorbed carbon dioxide from the atmosphere through photosynthesis suffered a serious decline, because of light's inability to penetrate the now-opaque waters. In turn, the plankton which broke down and released carbon saw a healthy increase in their numbers.
"The likely explanation is that so much organic carbon mobilized from the landscape into the surface water, and the organic carbon was available for aquatic organisms to use," Saros explained. "Because the lakes turned so brown, it reduced the light coming into the system, which tends to favor organisms that use organic carbon pathways instead of photosynthesis."
Experts observed this alteration in around 7,500 regional lakes sometime in 2023. The changes brought in by the extreme heat had "pushed Arctic lakes across a tipping point," as per researchers. These lakes are essential for residents living in West Greenland, as these water bodies supply them with drinking water and also sequester carbon. Researchers proposed to civilians that they identify organic and inorganic material in lakes, to evaluate how they want to go about treating it. Hence the results of the study and suggestions to improve the situation were shared with surrounding communities.
Researchers are currently attempting to figure out how the lakes can be treated and the way these water bodies will react to the remedies. For this pursuit, they are hoping for additional studies and monitoring. "It was such an overwhelming climate force that drove all the lakes to respond in the same way," Saros said. "When it comes to recovery, will it be the same across lakes or different?"