Lakes Aren't Just Drying Out. They Might Also Be Releasing More CO2
As part of a team exploring Utah's Great Salt Lake, climate researcher Melissa Cobo "discovered more disturbing evidence that dried-out lakes are a significant source of carbon dioxide emissions," reports the Washington Post. But more disturbingly, they write that this source of emissions "has not been included in the official accounting of how much carbon the world is releasing into the warming atmosphere."In a new study in the journal One Earth, the researchers calculated that 4.1 million tons of carbon dioxide and other greenhouse gases were released from the drying bed of the Great Salt Lake in 2020, the year Cobo and others collected the samples. This would amount to about a 7 percent increase in Utah's human-caused emissions, the authors found. While other researchers have documented carbon emissions from dried-out lakes - including the Aral Sea in Central Asia - [climate change museum curator Soren] Brothers said that his study tried to calculate what part of the emissions from this major saline lake could be attributed to humans, as the Great Salt Lake has been drawn down for human use, a decline worsened by climate change and the West's megadrought of the past two decades. "This is the first time we're saying, 'This is something that's on us,'" said Brothers, now a climate change curator with the Royal Ontario Museum. Lakes around the world normally store carbon. Plant and animal remains settle on the bottom over thousands of years as sediment, much of it in low-oxygen layers that degrade slowly. "When lakes are inundated with water, let's say their useful state, they are kind of allies in our struggle for removing CO2 from the atmosphere," said Rafael Marce, a research scientist at the Centre for Advanced Studies in Blanes, Spain, who has collaborated with Brothers on prior work but wasn't involved in this study. When lakes dry out, oxygen can penetrate deep into the sediment, waking up microorganisms that start to feast on the organic matter, releasing carbon dioxide, Marce said.
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