Litter degradation is a key process in the carbon cycle. To date, there is a lack of understanding of the mechanisms underlying decomposition of organic matter in arid and semi-arid zones. There are a few factors involved in this process that drive various decay mechanisms, as follows: (1) Litter quality or traits (nutrients and their ratio, structural components, morphological traits, and more), (2) humidity and water, driving microbial degradation, (3) UV and short-wave visible radiation (280-550 nm) driving photochemical degradation, (4) high temperature, driving thermal degradation. Notably, these decay mechanisms frequently interact and additional factors can come into play, such as litter position. This research will analyze the profile of changes in litter traits and CO₂ fluxes induced by single and combined decay mechanisms. Furthermore, the project will quantify in an extended field study the decay-derived CO₂ flux and turnover time of ‘dead’ carbon at the ecosystem scale. The overarching goal of this research is to determine the climatic impacts on the CO₂ flux derived from decomposition of organic materials in dryland ecosystems and to assess the contribution of the various decay mechanisms on the CO₂ flux. Information on climate effects will enable improved projections of the decay-derived CO₂ flux in drylands under a changed climate. Changes in litter functional traits during decomposition as affected by climate and litter type will shed new light on the functioning of the decay mechanisms. Information on the relative contributions of the decay mechanisms will further enhance our understanding of the control over decomposition and the concomitant CO₂ emissions from drylands.

Funding: ISF

Co-workers: Shai Schechter (PhD student) and Laura Bigio (Postdoc student)