Response of C and N cycles to N fertilization in Sphagnum and Molinia-dominated peat mesocosms
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摘要
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.
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.
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.
引文
Aerts,R.,Wallen,B.,Malmer,N.,1992.Growth-limiting nutrients in Sphagnum-dominated bogs subject to low and high atmospheric nitrogen supply.J.Ecol.131-140.
Bortoluzzi,E.,Epron,D.,Siegenthaler,A.,Gilbert,D.,Buttler,A.,2006.Carbon balance of a European mountain bog at contrasting stages of regeneration.New Phytol.172(4):708-718.https://doi.org/10.1111/j.1469-8137.2006.01859.x.
Bragazza,L.,Tahvanainen,T.,Kutnar,L.,Rydin,H.,Limpens,J.,Hájek,M.,et al.,2004.Nutritional constraints in ombrotrophic Sphagnum plants under increasing atmospheric nitrogen deposition in Europe.New Phytol.163(3),609-616.
Bragazza,L.,Freeman,C.,Jones,T.,Rydin,H.,Limpens,J.,Fenner,N.,et al.,2006.Atmospheric nitrogen deposition promotes carbon loss from peat bogs.Proc.Natl.Acad.Sci.U.S.A.103(51),19386-19389.
D'Angelo,B.,Gogo,S.,Laggoun-Défarge,F.,Le Moing,F.,Jégou,F.,Guimbaud,C.,2016.Soil temperature synchronisation improves representation of diel variability of ecosystem respiration in Sphagnum peatlands.Agric.For.Meteorol.223,95-102.
Francez,A.J.,Pinay,G.,Josselin,N.,Williams,B.L.,2011.Denitrification triggered by nitrogen addition in Sphagnum magellanicum peat.Biogeochemistry 106(3),435-441.
Gogo,S.,Laggoun-Défarge,F.,Delarue,F.,Lottier,N.,2011.Invasion of a Sphagnum-peatland by Betula spp and Molinia caerulea impacts organic matter biochemistry.Implications for carbon and nutrient cycling.Biogeochemistry 106(1),53-69.
Gogo,S.,Laggoun-Défarge,F.,Merzouki,F.,Mounier,S.,Guirimand-Dufour,A.,Jozja,N.,et al.,2016.In situ and laboratory non-additive litter mixture effect on C dynamics of Sphagnum rubellum and Molinia caerulea litters.J.Soils Sediments 16(1),13-27.
Gorham,E.,1991.Northern peatlands:role in the carbon cycle and probable responses to climatic warming.Ecol.Appl.1(2),182-195.
Granath,G.,Wiedermann,M.M.,Strengbom,J.,2009.Physiological responses to nitrogen and sulphur addition and raised temperature in Sphagnum balticum.Oecol 161(3),481-490.
Guimbaud,C.,Catoire,V.,Gogo,S.,Robert,C.,Chartier,M.,LaggounDéfarge,F.,et al.,2011.A portable infrared laser spectrometer for flux measurements of trace gases at the geosphere-atmosphere interface.Meas.Sci.Technol.22(7),075601.
Gunnarsson,U.,Boresj?Bronge,L.,Rydin,H.,Ohlson,M.,2008.Nearzero recent carbon accumulation in a bog with high nitrogen deposition in SW Sweden.Glob.Chang.Biol.14(9),2152-2165.
Hayden,M.J.,Ross,D.S.,2005.Denitrification as a nitrogen removal mechanism in a Vermont peatland.J.Environ.Qual.34(6),2052-2061.
Holland,E.A.,Dentener,F.J.,Braswell,B.H.,Sulzman,J.M.,1999.Contemporary and pre-industrial global reactive nitrogen budgets.Biogeochemistry 46(1),7-43.
Kandel,T.P.,Elsgaard,L.,L?rke,P.E.,2013.Measurement and modelling of CO2 flux from a drained fen peatland cultivated with reed canary grass and spring barley.GCB Bioenergy 5(5):548-561.https://doi.org/10.1111/gcbb.12020.
Lamarque,J.F.,Kiehl,J.T.,Brasseur,G.P.,Butler,T.,CameronSmith,P.,Collins,W.D.,et al.,2005.Assessing future nitrogen deposition and carbon cycle feedback using a multimodel approach:analysis of nitrogen deposition.J Geophys.Res:Atmos.110(D19).
Leroy,F.,Gogo,S.,Guimbaud,C.,Bernard-Jannin,L.,Hu,Z.,Laggoun-Défarge,F.,2017.Vegetation composition controls temperature sensitivity of CO2and CH4emissions and DOCconcentration in peatlands.Soil Biol.Biochem.107,164-167.
Leroy,F.,Gogo,S.,Guimbaud,C.,Bernard-Jannin,L.,Yin,X.,Belot,G.,Shuguang,W.,Laggoun-Défarge,F.,In prep Carbon balance and global warming potential modifications in Sphagnumdominated peat mesocosms invaded by Molinia caerulea.Submitted to Biogeosciences.
Limpens,J.,Granath,G.,Gunnarsson,U.,Aerts,R.,Bayley,S.,Bragazza,L.,et al.,2011.Climatic modifiers of the response to nitrogen deposition in peat-forming Sphagnum mosses:a metaanalysis.New Phytol.191(2),496-507.
Nyk?nen,H.,Vasander,H.,Huttunen,J.T.,Martikainen,P.J.,2002.Effect of experimental nitrogen load on methane and nitrous oxide fluxes on ombrotrophic boreal peatland.Plant Soil 242(1),147-155.
Repo,M.E.,Susiluoto,S.,Lind,S.E.,Jokinen,S.,Elsakov,V.,Biasi,C.,et al.,2009.Large N2O emissions from cryoturbated peat soil in tundra.Nat.Geosci.2(3),189-192.
Roobroeck,D.,Butterbach-Bahl,K.,Brueggemann,N.,Boeckx,P.,2010.Dinitrogen and nitrous oxide exchanges from an undrained monolith fen:short-term responses following nitrate addition.Eur.J.Soil Sci.61(5),662-670.
Tomassen,H.,Smolders,A.J.,Lamers,L.P.,Roelofs,J.G.,2003.Stimulated growth of Betula pubescens and Molinia caerulea on ombrotrophic bogs:role of high levels of atmospheric nitrogen deposition.J.Ecol.91(3),357-370.
Tomassen,H.,Smolders,A.J.,Limpens,J.,Lamers,L.P.,Roelofs,J.G.,2004.Expansion of invasive species on ombrotrophic bogs:desiccation or high N deposition?J.Appl.Ecol.41(1),139-150.
Troelstra,S.R.,Wagenaar,R.,Smant,W.,1995.Nitrogen utilization by plant species from acid heathland soils:I.Comparison between nitrate and ammonium nutrition at constant low pH1.J.Exp.Bot.1103-1112.
Turetsky,M.R.,Bond-Lamberty,B.,Euskirchen,E.,Talbot,J.,Frolking,S.,McGuire,A.D.,et al.,2012.The resilience and functional role of moss in boreal and arctic ecosystems.New Phytol.196(1),49-67.
Turunen,J.,Tomppo,E.,Tolonen,K.,Reinikainen,A.,2002.Estimating carbon accumulation rates of undrained mires in Finland-application to boreal and subarctic regions.The Holocene 12(1),69-80.
Van Breemen,N.,1995.How Sphagnum bogs down other plants.Trends Ecol.Evol.10(7),270-275.
Ward,S.E.,Ostle,N.J.,Oakley,S.,Quirk,H.,Henrys,P.A.,Bardgett,R.D.,2013.Warming effects on greenhouse gas fluxes in peatlands are modulated by vegetation composition.Ecol.Lett.16(10),1285-1293.
Wu,Y.,Blodau,C.,Moore,T.R.,Bubier,J.,Juutinen,S.,Larmola,T.,2015.Effects of experimental nitrogen deposition on peatland carbon pools and fluxes:a modelling analysis.Biogeosciences12(1),79-101.
Bortoluzzi,E.,Epron,D.,Siegenthaler,A.,Gilbert,D.,Buttler,A.,2006.Carbon balance of a European mountain bog at contrasting stages of regeneration.New Phytol.172(4):708-718.https://doi.org/10.1111/j.1469-8137.2006.01859.x.
Bragazza,L.,Tahvanainen,T.,Kutnar,L.,Rydin,H.,Limpens,J.,Hájek,M.,et al.,2004.Nutritional constraints in ombrotrophic Sphagnum plants under increasing atmospheric nitrogen deposition in Europe.New Phytol.163(3),609-616.
Bragazza,L.,Freeman,C.,Jones,T.,Rydin,H.,Limpens,J.,Fenner,N.,et al.,2006.Atmospheric nitrogen deposition promotes carbon loss from peat bogs.Proc.Natl.Acad.Sci.U.S.A.103(51),19386-19389.
D'Angelo,B.,Gogo,S.,Laggoun-Défarge,F.,Le Moing,F.,Jégou,F.,Guimbaud,C.,2016.Soil temperature synchronisation improves representation of diel variability of ecosystem respiration in Sphagnum peatlands.Agric.For.Meteorol.223,95-102.
Francez,A.J.,Pinay,G.,Josselin,N.,Williams,B.L.,2011.Denitrification triggered by nitrogen addition in Sphagnum magellanicum peat.Biogeochemistry 106(3),435-441.
Gogo,S.,Laggoun-Défarge,F.,Delarue,F.,Lottier,N.,2011.Invasion of a Sphagnum-peatland by Betula spp and Molinia caerulea impacts organic matter biochemistry.Implications for carbon and nutrient cycling.Biogeochemistry 106(1),53-69.
Gogo,S.,Laggoun-Défarge,F.,Merzouki,F.,Mounier,S.,Guirimand-Dufour,A.,Jozja,N.,et al.,2016.In situ and laboratory non-additive litter mixture effect on C dynamics of Sphagnum rubellum and Molinia caerulea litters.J.Soils Sediments 16(1),13-27.
Gorham,E.,1991.Northern peatlands:role in the carbon cycle and probable responses to climatic warming.Ecol.Appl.1(2),182-195.
Granath,G.,Wiedermann,M.M.,Strengbom,J.,2009.Physiological responses to nitrogen and sulphur addition and raised temperature in Sphagnum balticum.Oecol 161(3),481-490.
Guimbaud,C.,Catoire,V.,Gogo,S.,Robert,C.,Chartier,M.,LaggounDéfarge,F.,et al.,2011.A portable infrared laser spectrometer for flux measurements of trace gases at the geosphere-atmosphere interface.Meas.Sci.Technol.22(7),075601.
Gunnarsson,U.,Boresj?Bronge,L.,Rydin,H.,Ohlson,M.,2008.Nearzero recent carbon accumulation in a bog with high nitrogen deposition in SW Sweden.Glob.Chang.Biol.14(9),2152-2165.
Hayden,M.J.,Ross,D.S.,2005.Denitrification as a nitrogen removal mechanism in a Vermont peatland.J.Environ.Qual.34(6),2052-2061.
Holland,E.A.,Dentener,F.J.,Braswell,B.H.,Sulzman,J.M.,1999.Contemporary and pre-industrial global reactive nitrogen budgets.Biogeochemistry 46(1),7-43.
Kandel,T.P.,Elsgaard,L.,L?rke,P.E.,2013.Measurement and modelling of CO2 flux from a drained fen peatland cultivated with reed canary grass and spring barley.GCB Bioenergy 5(5):548-561.https://doi.org/10.1111/gcbb.12020.
Lamarque,J.F.,Kiehl,J.T.,Brasseur,G.P.,Butler,T.,CameronSmith,P.,Collins,W.D.,et al.,2005.Assessing future nitrogen deposition and carbon cycle feedback using a multimodel approach:analysis of nitrogen deposition.J Geophys.Res:Atmos.110(D19).
Leroy,F.,Gogo,S.,Guimbaud,C.,Bernard-Jannin,L.,Hu,Z.,Laggoun-Défarge,F.,2017.Vegetation composition controls temperature sensitivity of CO2and CH4emissions and DOCconcentration in peatlands.Soil Biol.Biochem.107,164-167.
Leroy,F.,Gogo,S.,Guimbaud,C.,Bernard-Jannin,L.,Yin,X.,Belot,G.,Shuguang,W.,Laggoun-Défarge,F.,In prep Carbon balance and global warming potential modifications in Sphagnumdominated peat mesocosms invaded by Molinia caerulea.Submitted to Biogeosciences.
Limpens,J.,Granath,G.,Gunnarsson,U.,Aerts,R.,Bayley,S.,Bragazza,L.,et al.,2011.Climatic modifiers of the response to nitrogen deposition in peat-forming Sphagnum mosses:a metaanalysis.New Phytol.191(2),496-507.
Nyk?nen,H.,Vasander,H.,Huttunen,J.T.,Martikainen,P.J.,2002.Effect of experimental nitrogen load on methane and nitrous oxide fluxes on ombrotrophic boreal peatland.Plant Soil 242(1),147-155.
Repo,M.E.,Susiluoto,S.,Lind,S.E.,Jokinen,S.,Elsakov,V.,Biasi,C.,et al.,2009.Large N2O emissions from cryoturbated peat soil in tundra.Nat.Geosci.2(3),189-192.
Roobroeck,D.,Butterbach-Bahl,K.,Brueggemann,N.,Boeckx,P.,2010.Dinitrogen and nitrous oxide exchanges from an undrained monolith fen:short-term responses following nitrate addition.Eur.J.Soil Sci.61(5),662-670.
Tomassen,H.,Smolders,A.J.,Lamers,L.P.,Roelofs,J.G.,2003.Stimulated growth of Betula pubescens and Molinia caerulea on ombrotrophic bogs:role of high levels of atmospheric nitrogen deposition.J.Ecol.91(3),357-370.
Tomassen,H.,Smolders,A.J.,Limpens,J.,Lamers,L.P.,Roelofs,J.G.,2004.Expansion of invasive species on ombrotrophic bogs:desiccation or high N deposition?J.Appl.Ecol.41(1),139-150.
Troelstra,S.R.,Wagenaar,R.,Smant,W.,1995.Nitrogen utilization by plant species from acid heathland soils:I.Comparison between nitrate and ammonium nutrition at constant low pH1.J.Exp.Bot.1103-1112.
Turetsky,M.R.,Bond-Lamberty,B.,Euskirchen,E.,Talbot,J.,Frolking,S.,McGuire,A.D.,et al.,2012.The resilience and functional role of moss in boreal and arctic ecosystems.New Phytol.196(1),49-67.
Turunen,J.,Tomppo,E.,Tolonen,K.,Reinikainen,A.,2002.Estimating carbon accumulation rates of undrained mires in Finland-application to boreal and subarctic regions.The Holocene 12(1),69-80.
Van Breemen,N.,1995.How Sphagnum bogs down other plants.Trends Ecol.Evol.10(7),270-275.
Ward,S.E.,Ostle,N.J.,Oakley,S.,Quirk,H.,Henrys,P.A.,Bardgett,R.D.,2013.Warming effects on greenhouse gas fluxes in peatlands are modulated by vegetation composition.Ecol.Lett.16(10),1285-1293.
Wu,Y.,Blodau,C.,Moore,T.R.,Bubier,J.,Juutinen,S.,Larmola,T.,2015.Effects of experimental nitrogen deposition on peatland carbon pools and fluxes:a modelling analysis.Biogeosciences12(1),79-101.