Effects of elevated atmospheric CO_2 and nitrogen fertilization on nitrogen cycling in experimental riparian wetlands
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摘要
Studies on the relationship between plant nitrogen content and soil nitrogen reduction under elevated CO_2 conditions and with different nitrogen additions in wetland ecosystems are lacking. This study was meant to assess the effects of elevated CO_2 concentrations and inorganic nitrogen additions on soil and plant nitrogen cycling. A cultured riparian wetland, alligator weeds, and two duplicated open top chambers(OTCs) with ambient(380 mmol/mol) and elevated(700 mmol/mol) CO_2 concentrations at low(4 mg/L) and high(6 mg/L) nitrogen fertilization levels were used. The total plant biomass increased by 30.77% and 31.37% at low and high nitrogen fertilization levels, respectively, under elevated CO_2 conditions. Plant nitrogen content decreased by 6.54% and 8.86% at low and high nitrogen fertilization levels, respectively. The coefficient of determination(R~2) of soil nitrogen contents ranged from 0.81 to 0.96. Under elevated CO_2 conditions, plants utilized the assimilated inorganic nitrogen(from the soil) for growth and other internal physiological transformations, which might explain the reduction in plant nitrogen content. A reduction in soil dissolved inorganic nitrogen(DIN) under elevated CO_2 conditions might have also caused the reduction in plant nitrogen content. Reduced plant and soil nitrogen contents are to be expected due to the potential exhaustive use of inorganic nitrogen by soil microorganisms even before it can be made available to the soil and plants. The results from this study provide important information to help policy makers make informed decisions on sustainable management of wetlands. Larger-scale field work is recommended in future research.
Studies on the relationship between plant nitrogen content and soil nitrogen reduction under elevated CO_2 conditions and with different nitrogen additions in wetland ecosystems are lacking. This study was meant to assess the effects of elevated CO_2 concentrations and inorganic nitrogen additions on soil and plant nitrogen cycling. A cultured riparian wetland, alligator weeds, and two duplicated open top chambers(OTCs) with ambient(380 mmol/mol) and elevated(700 mmol/mol) CO_2 concentrations at low(4 mg/L) and high(6 mg/L) nitrogen fertilization levels were used. The total plant biomass increased by 30.77% and 31.37% at low and high nitrogen fertilization levels, respectively, under elevated CO_2 conditions. Plant nitrogen content decreased by 6.54% and 8.86% at low and high nitrogen fertilization levels, respectively. The coefficient of determination(R~2) of soil nitrogen contents ranged from 0.81 to 0.96. Under elevated CO_2 conditions, plants utilized the assimilated inorganic nitrogen(from the soil) for growth and other internal physiological transformations, which might explain the reduction in plant nitrogen content. A reduction in soil dissolved inorganic nitrogen(DIN) under elevated CO_2 conditions might have also caused the reduction in plant nitrogen content. Reduced plant and soil nitrogen contents are to be expected due to the potential exhaustive use of inorganic nitrogen by soil microorganisms even before it can be made available to the soil and plants. The results from this study provide important information to help policy makers make informed decisions on sustainable management of wetlands. Larger-scale field work is recommended in future research.
Studies on the relationship between plant nitrogen content and soil nitrogen reduction under elevated CO_2 conditions and with different nitrogen additions in wetland ecosystems are lacking. This study was meant to assess the effects of elevated CO_2 concentrations and inorganic nitrogen additions on soil and plant nitrogen cycling. A cultured riparian wetland, alligator weeds, and two duplicated open top chambers(OTCs) with ambient(380 mmol/mol) and elevated(700 mmol/mol) CO_2 concentrations at low(4 mg/L) and high(6 mg/L) nitrogen fertilization levels were used. The total plant biomass increased by 30.77% and 31.37% at low and high nitrogen fertilization levels, respectively, under elevated CO_2 conditions. Plant nitrogen content decreased by 6.54% and 8.86% at low and high nitrogen fertilization levels, respectively. The coefficient of determination(R~2) of soil nitrogen contents ranged from 0.81 to 0.96. Under elevated CO_2 conditions, plants utilized the assimilated inorganic nitrogen(from the soil) for growth and other internal physiological transformations, which might explain the reduction in plant nitrogen content. A reduction in soil dissolved inorganic nitrogen(DIN) under elevated CO_2 conditions might have also caused the reduction in plant nitrogen content. Reduced plant and soil nitrogen contents are to be expected due to the potential exhaustive use of inorganic nitrogen by soil microorganisms even before it can be made available to the soil and plants. The results from this study provide important information to help policy makers make informed decisions on sustainable management of wetlands. Larger-scale field work is recommended in future research.
引文
Altmann,D.,Stief,P.,Amann,R.,de Beer,D.,2004.Nitrification in freshwater sediments as influenced by insect larvae:Quantification by microsensors and fluorescence in situ hybridization.Microb.Ecol.48(2),145e153.https://doi.org/10.1007/s00248-003-2015-6.
Balser,T.C.,Kinzig,A.P.,Firestone,M.K.,2001.Linking soil microbial communities and ecosystem functioning.In:Kinig,A.,Pacala,A.S.,Tilman,D.,eds.,The Functional Consequences of Biodiversity.Princeton University Press,Princeton,pp.265e293.
Balser,T.C.,Firestone,M.K.,2005.Linking microbial community composition and soil processes in a California annual grassland and mixed-conifer forest.Biogeochemistry 73(2),395e415.https://doi.org/10.1007/s10533-004-0372-y.
Berntson,G.M.,Bazzaz,F.A.,1998.Regenerating temperate forest microcosms in elevated CO2:Belowground growth and nitrogen cycling.Oecologia 113(1),115e125.https://doi.org/10.1007/s004420050359.
Billings,S.A.,Schaeffer,S.M.,Zitzer,S.,Charlet,T.,Smith,S.D.,Evans,R.D.,2002.Alterations of nitrogen dynamics under elevated CO2in an intact Mojave Desert ecosystem:Evidence from15N natural abundance.Oecologia 131(3),463e467.https://doi.org/10.1007/s00442-002-0898-4.
Bragazza,L.,Freeman,C.,Jones,T.,Rydin,H.,Limpens,J.,Fenner,N.,Ellis,T.,Gerdol,R.,Hajek,M.,Hajek,T.,et al.,2007.Atmospheric nitrogen deposition promotes carbon loss from peat bogs.Proc.Natl.Acad.Sci.103(51),19386e19389.https://doi.org/10.1073/pnas.0606629104.
Chen,Y.,Zhou,Y.,Yin,T.F.,Liu,C.X.,Luo,F.L.,2013.The invasive wetland plant Alternanthera philoxeroides shows a higher tolerance to waterlogging than its native congener Alternanthera sessilis.PLOS ONE 8(11),e81456.https://doi.org/10.1371/journal.pone.0081456.
Cotrufo,M.F.,Gorissen,A.,1997.Elevated CO2enhances below-ground Callocation in three perennial grass species at different levels of N availability.New Phytol.137(3),421e431.https://doi.org/10.1046/j.1469-8137.1997.00839.x.
Daepp,M.,Suter,D.,Almeida,P.F.,Isopp,H.,Hartwig,U.A.,Frehner,M.,Blum,H.,N€osberger,J.,Lu¨scher,A.,2000.Yield response of Lolium perenne swards to free air CO2enrichment increased over six years in a high N input system on fertile soil.Global Change Biol.6(7),805e816.https://doi.org/10.1046/j.1365-2486.2000.00359.x.
Deiglmayr,K.,Philippot,L.,Hartwig,U.A.,Kandeler,H.,2004.Structure and activity of the nitrate-reducing community in the rhizosphere of Lolium prenne and Trifolium repens under long-term elevated atmosphere CO2.FEMS Microbiol.Ecol.49(3),445e454.https://doi.org/10.1016/j.femsec.2004.04.017.
D?az,S.,Grime,J.P.,Harris,J.,Mcpherson,E.,1993.Evidence of a feedback mechanism limiting plant response to elevated carbon dioxide.Nature364(6438),616e617.https://doi.org/10.1038/364616a0.
Dijkstra,F.A.,Pendall,E.,Mosier,A.R.,King,J.Y.,Milchunas,D.G.,Morgan,J.A.,2008.Long-term enhancement of N availability and plant growth under elevated CO2in a semi-arid grassland.Funct.Ecol.22(6),975e982.https://doi.org/10.1111/j.1365-2435.2008.01398.x.
Gill,R.A.,Polley,H.W.,Johnson,H.B.,Anderson,L.J.,Maherali,H.,Jackson,R.B.,2002.Nonlinear grassland responses to past and future atmospheric CO2.Nature 417(6886),279e282.https://doi.org/10.1038/417279a.
Guo,X.L.,Lu,X.G.,Tian,K.,2010.Nitrogen cycling in plant-soil systems in three freshwater wetland types along a water level gradient in the Sanjiang Plain,Northeast China.Fresenius Environ.Bull.19(4),1e8.
Hagedorn,F.,van Hees,P.A.W.,Handa,I.T.,H€attenschwiler,S.,2008.Elevated atmospheric CO2fuels leaching of old dissolved organic matter at the alpine treeline.Global Biogeochem.Cycles 22(2).https://doi.org/10.1029/2007GB003026.
Hu,S.,Chapin,F.S.,Firestone,M.K.,Field,C.B.,Chiarello,N.R.,2001.Nitrogen limitation of microbial decomposition in grassland under elevated CO2.Nature 409(6817),188e191.https://doi.org/10.1038/35051576.
Hungate,B.A.,Canadell,J.,Chapin III,F.S.,1996.Plant species mediate changes in soil microbial N in response to elevated CO2.Ecology 77(8),2505e2515.https://doi.org/10.2307/2265749.
Hungate,B.A.,1999.Ecosystems responses to rising atmospheric CO2:Feedbacks through the N cycling.Carbon Dioxide and Environmental Stress.Academic Press,pp.265e285.https://doi.org/10.1016/B978-012460370-7/50011-5.
Koizumi,H.,Nakadai,T.,Usami,Y.,Satoh,M.,Shiyomi,M.,Oikawa,T.,1991.Effect of carbon dioxide concentration on microbial respiration in soil.Ecol.Res.6(3),227e232.https://doi.org/10.1007/BF02347124.
Luo,Q.,Krumholz,L.R.,Najar,F.Z.,Peacock,A.D.,Roe,B.A.,White,D.C.,Elshahed,M.S.,2005.Diversity of the microeukaryotic community in sulfide-rich zodletone spring(Oklahoma).Environ.Microbiol.71(10),6175e6184.https://doi.org/10.1128/AEM.71.10.6175-6184.2005.
Luo,Y.Q.,Su,B.,Currie,W.S.,Dukes,J.S.,Finzi,A.,Hartwig,U.,Hungate,B.,Mcmurtrie,R.E.,Oren,R.,Parton,W.J.,et al.,2004.Progressive nitrogen limitation of ecosystem response to rising atmospheric carbon dioxide.Bioscience 54(8),731e739.https://doi.org/10.1641/0006-3568(2004)054[0731:PNLOER]2.0.CO;2.
Martín-Olmedo,P.,Rees,R.M.,Grace,J.,2002.The influence of plants grown under elevated CO2and N fertilization on soil nitrogen dynamics.Global Change Biol.8(7),643e657.https://doi.org/10.1046/j.1365-2486.2002.00499.x.
Morgan,J.A.,Mosier,A.R.,Milchunas,D.G.,Lecain,D.R.,Nelson,J.A.,Parton,W.J.,2004.CO2enhance productivity,alters species composition,and reduces digestibility of shortgrass steppe vegetation.Ecol.Appl.14(1),208e219.https://doi.org/10.1890/02-5213.
Morgan,J.A.,Milchunas,D.G.,Lecain,D.R.,West,M.,Moisier,A.R.,2007.Carbon dioxide enrichment alters plant community structure and accelerates shrub growth in the shortgrass steppe.Proc.Natl.Acad.Sci.USA104(37),14724e14729.https://doi.org/10.1073/pnas.0703427104.
Norby,R.J.,1994.Issues and perspectives for investigating root responses to elevated atmospheric carbon dioxide.Plant Soil 165(1),9e20.https://doi.org/10.1007/BF00009958.
Pang,J.,Zhu,J.G.,Xie,Z.B.,Liu,G.,Zhang,Y.L.,Chen,G.P.,Zheng,Q.,Cheng,L.,2006.A new explanation of the N concentration decrease in tissue of rice(Oryza sativa L.)exposed to elevated atmospheric p CO2.Environ.Exp.Bot.57(1e2),98e105.https://doi.org/10.1016/j.envexpbot.2005.04.004.
Reich,P.B.,Knops,J.,Tilman,D.,Craine,J.,Ellsworth,D.,Tjoelkerd,M.,Lee,T.,Wedin,D.,Naeem,S.,Bahauddin,D.,et al.,2001.Plant diversity enhances ecosystem responses to elevated CO2and N deposition.Nature410(6830),809e812.https://doi.org/10.1038/35071062.
Reich,P.B.,Hungate,B.A.,Luo,Y.Q.,2006.Carbon-nitrogen interactions in terrestrial ecosystems in response to rising atmospheric carbon dioxide.Annu.Rev.Ecol.Evol.Syst.37,611e636.https://doi.org/10.1146/annurev.ecolsys.37.091305.110039.
van Groenigen,K.J.,Six,J.,Hungate,B.A.,de Graff,M.,van Breemer,N.,van Kessel,C.,2006.Element interactions limit soil carbon storage.PNAS103(17),6571e6574.https://doi.org/10.1073/pnas.0509038103.
Wang,A.O.,Jiang,X.X.,Zhang,Q.Q.,Zhou,J.,Li,H.L.,Luo,F.L.,Zhang,M.X.,Yu,F.H.,2014.Nitrogen addition increases intraspecific competition in the invasive wetland plant Alternanthera philoxeroides,but not in its native congener Alternanthera sessilis.Plant Species Biol.30(3),176e183.https://doi.org/10.1111/1442-1984.12048.
Balser,T.C.,Kinzig,A.P.,Firestone,M.K.,2001.Linking soil microbial communities and ecosystem functioning.In:Kinig,A.,Pacala,A.S.,Tilman,D.,eds.,The Functional Consequences of Biodiversity.Princeton University Press,Princeton,pp.265e293.
Balser,T.C.,Firestone,M.K.,2005.Linking microbial community composition and soil processes in a California annual grassland and mixed-conifer forest.Biogeochemistry 73(2),395e415.https://doi.org/10.1007/s10533-004-0372-y.
Berntson,G.M.,Bazzaz,F.A.,1998.Regenerating temperate forest microcosms in elevated CO2:Belowground growth and nitrogen cycling.Oecologia 113(1),115e125.https://doi.org/10.1007/s004420050359.
Billings,S.A.,Schaeffer,S.M.,Zitzer,S.,Charlet,T.,Smith,S.D.,Evans,R.D.,2002.Alterations of nitrogen dynamics under elevated CO2in an intact Mojave Desert ecosystem:Evidence from15N natural abundance.Oecologia 131(3),463e467.https://doi.org/10.1007/s00442-002-0898-4.
Bragazza,L.,Freeman,C.,Jones,T.,Rydin,H.,Limpens,J.,Fenner,N.,Ellis,T.,Gerdol,R.,Hajek,M.,Hajek,T.,et al.,2007.Atmospheric nitrogen deposition promotes carbon loss from peat bogs.Proc.Natl.Acad.Sci.103(51),19386e19389.https://doi.org/10.1073/pnas.0606629104.
Chen,Y.,Zhou,Y.,Yin,T.F.,Liu,C.X.,Luo,F.L.,2013.The invasive wetland plant Alternanthera philoxeroides shows a higher tolerance to waterlogging than its native congener Alternanthera sessilis.PLOS ONE 8(11),e81456.https://doi.org/10.1371/journal.pone.0081456.
Cotrufo,M.F.,Gorissen,A.,1997.Elevated CO2enhances below-ground Callocation in three perennial grass species at different levels of N availability.New Phytol.137(3),421e431.https://doi.org/10.1046/j.1469-8137.1997.00839.x.
Daepp,M.,Suter,D.,Almeida,P.F.,Isopp,H.,Hartwig,U.A.,Frehner,M.,Blum,H.,N€osberger,J.,Lu¨scher,A.,2000.Yield response of Lolium perenne swards to free air CO2enrichment increased over six years in a high N input system on fertile soil.Global Change Biol.6(7),805e816.https://doi.org/10.1046/j.1365-2486.2000.00359.x.
Deiglmayr,K.,Philippot,L.,Hartwig,U.A.,Kandeler,H.,2004.Structure and activity of the nitrate-reducing community in the rhizosphere of Lolium prenne and Trifolium repens under long-term elevated atmosphere CO2.FEMS Microbiol.Ecol.49(3),445e454.https://doi.org/10.1016/j.femsec.2004.04.017.
D?az,S.,Grime,J.P.,Harris,J.,Mcpherson,E.,1993.Evidence of a feedback mechanism limiting plant response to elevated carbon dioxide.Nature364(6438),616e617.https://doi.org/10.1038/364616a0.
Dijkstra,F.A.,Pendall,E.,Mosier,A.R.,King,J.Y.,Milchunas,D.G.,Morgan,J.A.,2008.Long-term enhancement of N availability and plant growth under elevated CO2in a semi-arid grassland.Funct.Ecol.22(6),975e982.https://doi.org/10.1111/j.1365-2435.2008.01398.x.
Gill,R.A.,Polley,H.W.,Johnson,H.B.,Anderson,L.J.,Maherali,H.,Jackson,R.B.,2002.Nonlinear grassland responses to past and future atmospheric CO2.Nature 417(6886),279e282.https://doi.org/10.1038/417279a.
Guo,X.L.,Lu,X.G.,Tian,K.,2010.Nitrogen cycling in plant-soil systems in three freshwater wetland types along a water level gradient in the Sanjiang Plain,Northeast China.Fresenius Environ.Bull.19(4),1e8.
Hagedorn,F.,van Hees,P.A.W.,Handa,I.T.,H€attenschwiler,S.,2008.Elevated atmospheric CO2fuels leaching of old dissolved organic matter at the alpine treeline.Global Biogeochem.Cycles 22(2).https://doi.org/10.1029/2007GB003026.
Hu,S.,Chapin,F.S.,Firestone,M.K.,Field,C.B.,Chiarello,N.R.,2001.Nitrogen limitation of microbial decomposition in grassland under elevated CO2.Nature 409(6817),188e191.https://doi.org/10.1038/35051576.
Hungate,B.A.,Canadell,J.,Chapin III,F.S.,1996.Plant species mediate changes in soil microbial N in response to elevated CO2.Ecology 77(8),2505e2515.https://doi.org/10.2307/2265749.
Hungate,B.A.,1999.Ecosystems responses to rising atmospheric CO2:Feedbacks through the N cycling.Carbon Dioxide and Environmental Stress.Academic Press,pp.265e285.https://doi.org/10.1016/B978-012460370-7/50011-5.
Koizumi,H.,Nakadai,T.,Usami,Y.,Satoh,M.,Shiyomi,M.,Oikawa,T.,1991.Effect of carbon dioxide concentration on microbial respiration in soil.Ecol.Res.6(3),227e232.https://doi.org/10.1007/BF02347124.
Luo,Q.,Krumholz,L.R.,Najar,F.Z.,Peacock,A.D.,Roe,B.A.,White,D.C.,Elshahed,M.S.,2005.Diversity of the microeukaryotic community in sulfide-rich zodletone spring(Oklahoma).Environ.Microbiol.71(10),6175e6184.https://doi.org/10.1128/AEM.71.10.6175-6184.2005.
Luo,Y.Q.,Su,B.,Currie,W.S.,Dukes,J.S.,Finzi,A.,Hartwig,U.,Hungate,B.,Mcmurtrie,R.E.,Oren,R.,Parton,W.J.,et al.,2004.Progressive nitrogen limitation of ecosystem response to rising atmospheric carbon dioxide.Bioscience 54(8),731e739.https://doi.org/10.1641/0006-3568(2004)054[0731:PNLOER]2.0.CO;2.
Martín-Olmedo,P.,Rees,R.M.,Grace,J.,2002.The influence of plants grown under elevated CO2and N fertilization on soil nitrogen dynamics.Global Change Biol.8(7),643e657.https://doi.org/10.1046/j.1365-2486.2002.00499.x.
Morgan,J.A.,Mosier,A.R.,Milchunas,D.G.,Lecain,D.R.,Nelson,J.A.,Parton,W.J.,2004.CO2enhance productivity,alters species composition,and reduces digestibility of shortgrass steppe vegetation.Ecol.Appl.14(1),208e219.https://doi.org/10.1890/02-5213.
Morgan,J.A.,Milchunas,D.G.,Lecain,D.R.,West,M.,Moisier,A.R.,2007.Carbon dioxide enrichment alters plant community structure and accelerates shrub growth in the shortgrass steppe.Proc.Natl.Acad.Sci.USA104(37),14724e14729.https://doi.org/10.1073/pnas.0703427104.
Norby,R.J.,1994.Issues and perspectives for investigating root responses to elevated atmospheric carbon dioxide.Plant Soil 165(1),9e20.https://doi.org/10.1007/BF00009958.
Pang,J.,Zhu,J.G.,Xie,Z.B.,Liu,G.,Zhang,Y.L.,Chen,G.P.,Zheng,Q.,Cheng,L.,2006.A new explanation of the N concentration decrease in tissue of rice(Oryza sativa L.)exposed to elevated atmospheric p CO2.Environ.Exp.Bot.57(1e2),98e105.https://doi.org/10.1016/j.envexpbot.2005.04.004.
Reich,P.B.,Knops,J.,Tilman,D.,Craine,J.,Ellsworth,D.,Tjoelkerd,M.,Lee,T.,Wedin,D.,Naeem,S.,Bahauddin,D.,et al.,2001.Plant diversity enhances ecosystem responses to elevated CO2and N deposition.Nature410(6830),809e812.https://doi.org/10.1038/35071062.
Reich,P.B.,Hungate,B.A.,Luo,Y.Q.,2006.Carbon-nitrogen interactions in terrestrial ecosystems in response to rising atmospheric carbon dioxide.Annu.Rev.Ecol.Evol.Syst.37,611e636.https://doi.org/10.1146/annurev.ecolsys.37.091305.110039.
van Groenigen,K.J.,Six,J.,Hungate,B.A.,de Graff,M.,van Breemer,N.,van Kessel,C.,2006.Element interactions limit soil carbon storage.PNAS103(17),6571e6574.https://doi.org/10.1073/pnas.0509038103.
Wang,A.O.,Jiang,X.X.,Zhang,Q.Q.,Zhou,J.,Li,H.L.,Luo,F.L.,Zhang,M.X.,Yu,F.H.,2014.Nitrogen addition increases intraspecific competition in the invasive wetland plant Alternanthera philoxeroides,but not in its native congener Alternanthera sessilis.Plant Species Biol.30(3),176e183.https://doi.org/10.1111/1442-1984.12048.