New Climate 'Feedback Loop' Discovered in Freshwater Lakes

As per a new study conducted over the chemical reactions that take place upon the decomposition of organic matter in freshwater, it has been discovered that the debris from trees suppresses production of methane. On the contrary the debris from plants found in reed beds indeed increases this harmful greenhouse gas.

It is estimated that with the loss of forest cover and increase in the wetlands, the emissions from the freshwater lakes could double in the coming fifty years. Methane is a potential greenhouse gas that is about 25% more potent than carbon dioxide. It is believed that a new mechanism has been discovered that can cause more greenhouse gases. The warm climates that increases the growth of aquatic plants have the capacity to initiate a damaging feedback loop in natural ecosystems. The scientists conducted an experiment wherein they took lake sediments and added three common types of plant debris: deciduous trees that shed leaves annually, evergreen pine-shedding coniferous trees, and cattails (often known in the UK as 'bulrushes') - a common aquatic plant that grows in the shallows of freshwater lakes. These sediments were incubated in the lab for 150 days. Simultaneously, the scientists siphoned off and measured the methane produced. They observed that the bulrush sediment produced over 400 times the amount of methane as the coniferous sediment, and almost 2,800 times the methane than that of the deciduous. The researchers further "spiked" the three samples with the microbes that produce methane to gauge the chemical reaction. They concluded that the forest-derived sediment remained unchanged, but the sample containing the bulrush organic matter doubled its methane production.

By: Anuja Arora

Content: https://phys.org/news/2018-05-greenhouse-gas-feedback-loop-freshwater.html