Climate change can cause the levels of greenhouse gases emitted by freshwater northern lakes to increase between 1.4 and 2.3 times, according to a study. Researchers from the University of Cambridge in the UK noted that every drop of freshwater contains millions of different organic molecules that have previously gone unnoticed. Small shallow lakes dominate the world’s freshwater area, and the sediments within them already account for at least one-quarter of all carbon-dioxide, and more than two-thirds of all methane emitted from lakes into our environment, the authors said.
“What we’ve traditionally called ‘carbon’ in freshwater turns out to be a super-diverse mixture of different carbon-based organic molecules,” said Andrew Tanentzap from Cambridge, who led the research published recently. “We’ve been measuring ‘carbon’ in freshwater as a proxy for everything from water quality to the productivity of freshwater ecosystems. Now we’ve realized that it’s the diversity of this invisible world of organic molecules that are important,” Tanentzap said in a statement. As the climate warms, vegetation cover is growing in forests of the northern latitudes, the researchers further stated. By simulating this effect in two lakes in Ontario, Canada, the research found an augmented diversity of organic molecules containing carbon within their composition entering the water in the matter shed by near trees and plants.
During the research, containers were filled with varying ratios of rocks and organic material — consisting of deciduous and coniferous litter from nearby forests –and submerged in the shallow waters of the two lakes. Accurately predicting carbon emissions from natural systems is very important to the dependability of calculations used to know the pace of climate change, and the effects of a humid world, researchers added. “Climate change will increase forest cover and change species composition, resulting in a greater variety of leaves and plant litter falling into waterways. We found that the resulting increase in the diversity of organic molecules in the water leads to higher greenhouse gas concentrations,” said Tanentzap. He noted that understanding these connections means researchers could look at ways to decrease carbon emissions in the future, for instance, by changing land management practices. The researchers said that changing the vegetation around freshwater lakes areas could change the organic molecules that finally end up in the water.