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Sílvia Poblador: Mediterranean riparian soils: sinks or sources of greenhouse gases? The role of soil water content

Seminar: Akvatisk biologi

07.01.2019 | Anne Kirstine Mehlsen

Dato tor 17 jan
Tid 09:45 10:30
Sted Institut for Bioscience, Ole Worms Allé 1, bygning 1135-234

Foredragsholder: Sílvia Poblador, University of Barcelona

Abstract:

Riparian zones play a fundamental role in regulating the amount of carbon (C) and nitrogen (N) that is exported from catchments to the streams. However, C and N removal via soil gaseous pathways can influence local budgets of greenhouse gas (GHG) emissions and contribute to climate change. Over a year, we quantified soil effluxes of carbon dioxide (CO2) and nitrous oxide (N2O) from a Mediterranean riparian forest in order to understand the role of these ecosystems on catchment GHG emissions. In addition, we evaluated the main soil microbial processes that produce GHG (mineralization, nitrification, and denitrification) and how changes in soil properties can modify the GHG production over time and space. Riparian soils emitted larger amounts of CO2 than N2O to the atmosphere attributed to high respiration and low denitrification rates. Both CO2 and N2O emissions showed a marked (but antagonistic) spatial gradient as a result of variations in soil water content across the riparian zone. However, both CO2 and N2O emissions peaked after spring rewetting events, when optimal conditions of soil water content, temperature, and N availability favor microbial respiration, nitrification, and denitrification. Overall, these results highlight the role of water availability on riparian soil biogeochemistry and GHG emissions and suggest that climate change alterations in hydrologic regimes can affect the microbial processes that produce GHG as well as the contribution of these systems to regional and global biogeochemical cycles.

Institut for Bioscience, Offentligheden / Pressen, Medarbejdere