Response of biogeochemical processes of the water-soil-plant system to experimental flooding-drying conditions in a eutrophic wetland: the role of Phragmites australis
2015
Tercero, M. C. | Álvarez-Rogel, J. | Conesa, H. M. | Ferrer, M. A. | Calderón, A. A. | López-Orenes, A. | González-Alcaraz, M. N.
AIMS: Assess the role of Phragmites australis in the temporal variability of physico-chemical and microbiological soil properties related to biogeochemical processes in eutrophic wetlands. METHODS: A mesocosms experiment was performed with alternating flooding-drying conditions with eutrophic water at two nutrient levels, and soil Eh, pH, temperature, CO₂ emissions, dissolved organic carbon, carbon from microbial biomass, and Phragmites physiological activity were measured during 44 weeks. RESULTS: In surface, Eh decreased with flooding and increased with drying regardless plant presence and nutrients content. In depth, Phragmites maintained oxic conditions. During warmer months, O₂ diffusion promoted by Phragmites hindered the drop of pH. Soil microbial respiration was stimulated in warmer months (soil temperature ~ 20–30 °C), as shown by larger CO₂ production, and higher aromaticity and phenolic compounds content in pore water. The latter occurred regardless the plant presence and nutrients content, although the combination of both contributed to a higher microbial population (shown by higher concentrations of carbon from microbial biomass). CONCLUSIONS: The presence of Phragmites and the nutrient concentration in the flooding water had a different role in the temporal evolution of the physico-chemical and microbiological soil properties in eutrophic wetlands, and this role was strongly influenced by soil depth and temperature.
显示更多 [+] 显示较少 [-]