Plant communities play an important role in the C-sink function of peatlands. However,global change and local perturbations are expected to modify peatland plant communities,leading to a shift from Sphagnum mosses to ...Plant communities play an important role in the C-sink function of peatlands. However,global change and local perturbations are expected to modify peatland plant communities,leading to a shift from Sphagnum mosses to vascular plants. Most studies have focused on the direct effects of modification in plant communities or of global change(such as climate warming, N fertilization) in peatlands without considering interactions between these disturbances that may alter peatlands' C function. We set up a mesocosm experiment to investigate how Greenhouse Gas(CO_2, CH_4, N_2O) fluxes, and dissolved organic carbon(DOC)and total dissolved N(TN) contents are affected by a shift from Sphagnum mosses to Molinia caerulea dominated peatlands combined with N fertilization. Increasing N deposition did not alter the C fluxes(CO_2 exchanges, CH_4 emissions) or DOC content. The lack of N effect on the C cycle seems due to the capacity of Sphagnum to efficiently immobilize N. Nevertheless, N supply increased the N_2O emissions, which were also controlled by the plant communities with the presence of Molinia caerulea reducing N_2O emissions in the Sphagnum mesocosms. Our study highlights the role of the vegetation composition on the C and N fluxes in peatlands and their responses to the N deposition. Future research should now consider the climate change in interaction to plants community modifications due to their controls of peatland sensitivity to environmental conditions.展开更多
Aims and Methods Vascular plants are known to influence the production,transport and oxidation of methane in wetland soils,but these processes are not well understood.using plants grown in intact peat cores,we compare...Aims and Methods Vascular plants are known to influence the production,transport and oxidation of methane in wetland soils,but these processes are not well understood.using plants grown in intact peat cores,we compared the influence upon methane emissions of 20 forb and graminoid species from European wetlands.We measured plant-mediated transport of methane(conduit or chimney effect)using a novel agar-sealing technique that prevented methane exchange from the bare soil to the atmosphere.Important Findings the plant-mediated transport(chimney effect)represented between 30%and almost 100%of the total methane flux,with graminoids exhibiting greater internal transport than forbs.In general,plants with less dense root tissues and a relatively larger root volume exhibited a larger chimney effect.most species(12 out of 20)signif-icantly reduced methane emissions compared to bare soil and only one species,Succisa pratensis,increased them.We suggest that characterising vegetation in terms of plant functional traits and plant processes offers an effective method for estimating methane emis-sions from wetlands.However,we found no correlation between the magnitude of the chimney effect and the overall influence of different plant species on methane emissions.besides introducing a useful tool to study plant-mediated transport,this work suggests that characterising vegetation in terms of functional traits could improve estimates of methane emissions from wetlands,which in turn could help in designing mitigation strategies.展开更多
基金research conducted in the Labex VOLTAIRE (ANR-10-LABX-100-01)the financial support provided to the PIVOTS project by the Région Centre–Val de Loire:ARD 2020 program,CPER 2015-2020,the European Union who invests in Centre-Val de Loire with the European Regional Development Fundsupported by the AMIS(FAte and IMpact of AtmospherIc PollutantS)project funded by the European Union,under the Marie Curie Actions IRSES(International Research Staff Exchange Scheme),within the Seventh Framework ProgrammeFP7-PEOPLE-2011-IRSES
文摘Plant communities play an important role in the C-sink function of peatlands. However,global change and local perturbations are expected to modify peatland plant communities,leading to a shift from Sphagnum mosses to vascular plants. Most studies have focused on the direct effects of modification in plant communities or of global change(such as climate warming, N fertilization) in peatlands without considering interactions between these disturbances that may alter peatlands' C function. We set up a mesocosm experiment to investigate how Greenhouse Gas(CO_2, CH_4, N_2O) fluxes, and dissolved organic carbon(DOC)and total dissolved N(TN) contents are affected by a shift from Sphagnum mosses to Molinia caerulea dominated peatlands combined with N fertilization. Increasing N deposition did not alter the C fluxes(CO_2 exchanges, CH_4 emissions) or DOC content. The lack of N effect on the C cycle seems due to the capacity of Sphagnum to efficiently immobilize N. Nevertheless, N supply increased the N_2O emissions, which were also controlled by the plant communities with the presence of Molinia caerulea reducing N_2O emissions in the Sphagnum mesocosms. Our study highlights the role of the vegetation composition on the C and N fluxes in peatlands and their responses to the N deposition. Future research should now consider the climate change in interaction to plants community modifications due to their controls of peatland sensitivity to environmental conditions.
文摘Aims and Methods Vascular plants are known to influence the production,transport and oxidation of methane in wetland soils,but these processes are not well understood.using plants grown in intact peat cores,we compared the influence upon methane emissions of 20 forb and graminoid species from European wetlands.We measured plant-mediated transport of methane(conduit or chimney effect)using a novel agar-sealing technique that prevented methane exchange from the bare soil to the atmosphere.Important Findings the plant-mediated transport(chimney effect)represented between 30%and almost 100%of the total methane flux,with graminoids exhibiting greater internal transport than forbs.In general,plants with less dense root tissues and a relatively larger root volume exhibited a larger chimney effect.most species(12 out of 20)signif-icantly reduced methane emissions compared to bare soil and only one species,Succisa pratensis,increased them.We suggest that characterising vegetation in terms of plant functional traits and plant processes offers an effective method for estimating methane emis-sions from wetlands.However,we found no correlation between the magnitude of the chimney effect and the overall influence of different plant species on methane emissions.besides introducing a useful tool to study plant-mediated transport,this work suggests that characterising vegetation in terms of functional traits could improve estimates of methane emissions from wetlands,which in turn could help in designing mitigation strategies.
