Rising Temperatures Lead to Unexpectedly Rapid Carbon Release From Soils

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How sensitively does organic carbon stored in soils react to changes in temperature and humidity?

How sensitively does organic carbon stored in soils react to changes in temperature and humidity? This question is central to a new study by researchers from MARUM – Center for Marine Environmental Sciences at the University of Bremen and from the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research in Bremerhaven that was now published in Nature Communications.

Globally, soils store more than twice as much carbon as the atmosphere. Therefore, carbon uptake and release by soils constitutes a strong regulator of atmospheric concentrations of the greenhouse gas carbon dioxide (CO2). In the context of the ongoing anthropogenic climate change it is thus important to better understand the sensitivity of soil carbon, which is directly related to the release of CO2 from soils, under a changing climate, such as rising temperatures and/or variations in the hydrological cycle.

Studies have already highlighted the importance of permafrost regions, where rising temperatures lead to the release of carbon from previously frozen soils. However, large amounts of organic carbon are also stored in soils in subtropical and tropical regions. In these regions, it was previously unclear what the main factor for a change in the carbon turnover rate was. "Microbes that break down organic matter are generally more active under warm and humid conditions, so the carbon content in tropical soils responds very quickly to climatic changes. Some studies report a main influence of changing hydroclimatic conditions, while in others temperature plays the main role," explains first author Dr. Vera Meyer from MARUM.

Read more at: Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research

Mini-Carbon Dating System (MICADAS) (Photo Credit: Gesine Mollenhauer)