Potential microbial activity and CO2 emission during plant-litter decomposition in a Mediterranean ecosystem during the rainless season


Plant-litter decomposition is an essential step in the carbon cycle, and, thus, significantly affects the atmospheric CO2 concentration. In the vast dryland regions of the globe, litter decays year-round, though much less is known about decomposition during the rainless dry season than during the wet season. Recently, absorption of atmospheric water vapor was described as a primary driver of decomposition during rainless seasons, but the mechanism by which litter decays under this driver is unknown so far. The objective of the proposed study is to assess microbial activity contributing to plant-litter decay and nutrient cycling in dry areas during the rainless season. Studies with various types of plant litter in a Mediterranean shrubland and in the lab will assess microbial degradation of litter using extracellular enzyme activity and CO2 emission. Since the rate of microbial decay and of CO2 emission can increase with litter nitrogen content, we will estimate nitrogen fixation rates on litter, a component of the nitrogen cycle that has been neglected so far. Decomposition driven by water-vapor absorption will become more prominent in a future warmer and drier world. Hence, the proposed study has implications for predicting regional and global CO2 fluxes under global climate change by coupled climate carbon-cycle models.

Publications: Gliksman D, Rey A, Seligmann R, Dumbur R, Sperling O, Navon Y, Haenel S, De Angelis P, Arnone JA, III, Grünzweig JM. 2016. Biotic degradation at night, abiotic degradation at day: positive feedbacks on litter decomposition in drylands. Global Change Biology (accepted for publication).

Co-workers: Daniel Gliksman (PhD student)

Partner organizations: Ring Center for Inter-Disciplinary Environmental Research