Greenhouse gas emissions from soil under changing environmental conditions (Guest Editors' Introduction)

Abstract

First paragraph: Exchange of greenhouse gases (GHGs) between soils and the atmosphere is a natural consequence of several ecosystem processes (Schlesinger & Bernhardt, 2013). The balance of exchange contributes to the global atmospheric GHG budget, in which soils can act as either a net source or sink of GHGs. Key ecosystem processes participating in GHG uptake and emissions are plant photosynthesis (resulting in organic matter input to soils), plant respiration, animal and soil microbial respiration (both aerobic and anaerobic), fire and soil microbial transformations of nitrogen (N). There are also many human-induced transformations that create GHG emissions, either directly through burning of fossil fuels and industrial processing of mined natural resources or indirectly through land-use change, manipulation of natural processes through various management strategies, altering natural cycles of water and nutrients and changing energy flows. Humaninduced changes to the exchange of GHGs among plants, soils and the atmosphere are not limited to their effects on the atmospheric burden of GHGs: significant changes to the land surface of our planet itself have created challenges that require understanding of how a changing environment feeds back to affect GHG emissions (Richter et al., 2011).