1
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Feron S, Malhotra A, Bansal S, Fluet-Chouinard E, McNicol G, Knox SH, Delwiche KB, Cordero RR, Ouyang Z, Zhang Z, Poulter B, Jackson RB. Recent increases in annual, seasonal, and extreme methane fluxes driven by changes in climate and vegetation in boreal and temperate wetland ecosystems. GLOBAL CHANGE BIOLOGY 2024; 30:e17131. [PMID: 38273508 DOI: 10.1111/gcb.17131] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Revised: 11/15/2023] [Accepted: 12/15/2023] [Indexed: 01/27/2024]
Abstract
Climate warming is expected to increase global methane (CH4 ) emissions from wetland ecosystems. Although in situ eddy covariance (EC) measurements at ecosystem scales can potentially detect CH4 flux changes, most EC systems have only a few years of data collected, so temporal trends in CH4 remain uncertain. Here, we use established drivers to hindcast changes in CH4 fluxes (FCH4 ) since the early 1980s. We trained a machine learning (ML) model on CH4 flux measurements from 22 [methane-producing sites] in wetland, upland, and lake sites of the FLUXNET-CH4 database with at least two full years of measurements across temperate and boreal biomes. The gradient boosting decision tree ML model then hindcasted daily FCH4 over 1981-2018 using meteorological reanalysis data. We found that, mainly driven by rising temperature, half of the sites (n = 11) showed significant increases in annual, seasonal, and extreme FCH4 , with increases in FCH4 of ca. 10% or higher found in the fall from 1981-1989 to 2010-2018. The annual trends were driven by increases during summer and fall, particularly at high-CH4 -emitting fen sites dominated by aerenchymatous plants. We also found that the distribution of days of extremely high FCH4 (defined according to the 95th percentile of the daily FCH4 values over a reference period) have become more frequent during the last four decades and currently account for 10-40% of the total seasonal fluxes. The share of extreme FCH4 days in the total seasonal fluxes was greatest in winter for boreal/taiga sites and in spring for temperate sites, which highlights the increasing importance of the non-growing seasons in annual budgets. Our results shed light on the effects of climate warming on wetlands, which appears to be extending the CH4 emission seasons and boosting extreme emissions.
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Affiliation(s)
- Sarah Feron
- Knowledge Infrastructures, Campus Fryslân, University of Groningen, Groningen, The Netherlands
- Department of Earth System Science, Stanford University, Stanford, California, USA
- Department of Physics, Universidad de Santiago, Santiago, Chile
| | - Avni Malhotra
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, Washington, USA
| | - Sheel Bansal
- U.S. Geological Survey, Northern Prairie Wildlife Research Center, Jamestown, North Dakota, USA
| | - Etienne Fluet-Chouinard
- Earth Systems Science Division, Pacific Northwest National Laboratory, Richland, Washington, USA
| | - Gavin McNicol
- Department of Earth System Science, Stanford University, Stanford, California, USA
- Department of Earth and Environmental Sciences, University of Illinois Chicago, Chicago, Illinois, USA
| | - Sara H Knox
- Department of Geography, The University of British Columbia, Vancouver, British Columbia, Canada
- Department of Geography, McGill University, Montreal, Quebec, Canada
| | - Kyle B Delwiche
- Department of Earth System Science, Stanford University, Stanford, California, USA
- Department of Environmental Science, Policy, and Management, University of California, Berkeley, California, USA
| | - Raul R Cordero
- Department of Physics, Universidad de Santiago, Santiago, Chile
| | - Zutao Ouyang
- Department of Earth System Science, Stanford University, Stanford, California, USA
| | - Zhen Zhang
- Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, China
| | - Benjamin Poulter
- Biospheric Sciences Laboratory, NASA Goddard Space Flight Center, Greenbelt, Maryland, USA
| | - Robert B Jackson
- Department of Earth System Science, Stanford University, Stanford, California, USA
- Woods Institute for the Environment, Stanford University, Stanford, California, USA
- Precourt Institute for Energy, Stanford, California, USA
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2
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Han L, Ganjurjav H, Hu G, Wu J, Yan Y, Danjiu L, He S, Xie W, Yan J, Gao Q. Nitrogen Addition Affects Ecosystem Carbon Exchange by Regulating Plant Community Assembly and Altering Soil Properties in an Alpine Meadow on the Qinghai-Tibetan Plateau. FRONTIERS IN PLANT SCIENCE 2022; 13:900722. [PMID: 35769289 PMCID: PMC9234307 DOI: 10.3389/fpls.2022.900722] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Accepted: 05/13/2022] [Indexed: 05/11/2023]
Abstract
Nitrogen (N) deposition can affect the global ecosystem carbon balance. However, how plant community assembly regulates the ecosystem carbon exchange in response to the N deposition remains largely unclear, especially in alpine meadows. In this study, we conducted a manipulative experiment to examine the impacts of N (ammonium nitrate) addition on ecosystem carbon dioxide (CO2) exchange by changing the plant community assembly and soil properties at an alpine meadow site on the Qinghai-Tibetan Plateau from 2014 to 2018. The N-addition treatments were N0, N7, N20, and N40 (0, 7, 20, and 40 kg N ha-1year-1) during the plant growing season. The net ecosystem CO2 exchange (NEE), gross ecosystem productivity (GEP), and ecosystem respiration (ER) were measured by a static chamber method. Our results showed that the growing-season NEE, ER and GEP increased gradually over time with increasing N-addition rates. On average, the NEE increased significantly by 55.6 and 65.2% in N20 and N40, respectively (p < 0.05). Nitrogen addition also increased forage grass biomass (GB, including sedge and Gramineae) by 74.3 and 122.9% and forb biomass (FB) by 73.4 and 51.4% in N20 and N40, respectively (p < 0.05). There were positive correlations between CO2 fluxes (NEE and GEP) and GB (p < 0.01), and the ER was positively correlated with functional group biomass (GB and FB) and soil available N content (NO3 --N and NH4 +-N) (p < 0.01). The N-induced shift in the plant community assembly was primarily responsible for the increase in NEE. The increase in GB mainly contributed to the N stimulation of NEE, and FB and the soil available N content had positive effects on ER in response to N addition. Our results highlight that the plant community assembly is critical in regulating the ecosystem carbon exchange response to the N deposition in alpine ecosystems.
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Affiliation(s)
- Ling Han
- Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Hasbagan Ganjurjav
- Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, Beijing, China
- National Agricultural Experimental Station for Agricultural Environment, Nagqu, China
| | - Guozheng Hu
- Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, Beijing, China
- National Agricultural Experimental Station for Agricultural Environment, Nagqu, China
| | - Jianshuang Wu
- Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Yulong Yan
- China New Era Group Corporation, Beijing, China
| | | | | | | | - Jun Yan
- Nagqu Grassland Station, Nagqu, China
| | - Qingzhu Gao
- Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, Beijing, China
- National Agricultural Experimental Station for Agricultural Environment, Nagqu, China
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3
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Zhang Y, Song C, Wang X, Chen N, Zhang H, Du Y, Zhang Z, Zhu X. Warming effects on the flux of CH 4 from peatland mesocosms are regulated by plant species composition: Richness and functional types. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 806:150831. [PMID: 34627884 DOI: 10.1016/j.scitotenv.2021.150831] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Revised: 09/27/2021] [Accepted: 10/02/2021] [Indexed: 06/13/2023]
Abstract
Peatlands in northeast China are experiencing severe climate warming. Most studies on peatlands focus on the responses of CH4 dynamics to temperature. However, they rarely consider the synchronous changes in the composition of plant communities caused by the expansion of vascular plants. In this study, an experiment combined warming with the manipulation of plants to examine the concentrations of CH4 porewater and its fluxes in the mesocosm. We found that warming increased the concentration of CH4 and its fluxes relative to the control treatments, and it was strongly modulated by plant richness and functional types. The average CH4 fluxes in the warming and non-warming mesocosms varied from 72.10 to 119.44 and 97.95 to 194.43 mg m-2 h-1, respectively. Plant species richness significantly increased CH4 flux at the warming level of 3.2 °C (P < 0.01). The presence of vascular plants, such as Carex globularis and Vaccinium uliginosum, significantly increased the CH4 fluxes after warming had occurred. Our results suggest that the distinct response of CH4 to richness and species primarily stemmed from the direct or indirect effects of plant biomass and functional characteristics. Therefore, more consideration should be given to the diversity changes caused by vascular plant expansion when estimating CH4 flux in boreal peatland, especially in the context of future climate warming.
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Affiliation(s)
- Yifei Zhang
- Key Laboratory of Wetland Ecology and Environment, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130102, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Changchun Song
- Key Laboratory of Wetland Ecology and Environment, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130102, China; School of Hydraulic Engineering, Dalian University of Technology, Dalian 116023, China.
| | - Xianwei Wang
- Key Laboratory of Wetland Ecology and Environment, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130102, China
| | - Ning Chen
- Key Laboratory of Wetland Ecology and Environment, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130102, China
| | - Hao Zhang
- Key Laboratory of Wetland Ecology and Environment, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130102, China
| | - Yu Du
- Key Laboratory of Wetland Ecology and Environment, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130102, China
| | - Zhengang Zhang
- Key Laboratory of Wetland Ecology and Environment, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130102, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xinhao Zhu
- Key Laboratory of Wetland Ecology and Environment, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130102, China
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4
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AminiTabrizi R, Dontsova K, Graf Grachet N, Tfaily MM. Elevated temperatures drive abiotic and biotic degradation of organic matter in a peat bog under oxic conditions. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 804:150045. [PMID: 34798718 DOI: 10.1016/j.scitotenv.2021.150045] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2021] [Revised: 08/26/2021] [Accepted: 08/26/2021] [Indexed: 06/13/2023]
Abstract
Understanding the effects of elevated temperatures on soil organic matter (SOM) decomposition pathways in northern peatlands is central to predicting their fate under future warming. Peatlands role as carbon (C) sink is dependent on both anoxic conditions and low temperatures that limit SOM decomposition. Previous studies have shown that elevated temperatures due to climate change can disrupt peatland's C balance by enhancing SOM decomposition and increasing CO2 emissions. However, little is known about how SOM decomposition pathways change at higher temperatures. Here, we used an integrated research approach to investigate the mechanisms behind enhanced CO2 emissions and SOM decomposition under elevated temperatures of surface peat soil collected from a raised and Sphagnum dominated mid-continental bog (S1 bog) peatland at the Marcel Experimental Forest in Minnesota, USA, incubated under oxic conditions at three different temperatures (4, 21, and 35 °C). Our results indicated that elevated temperatures could destabilize peatland's C pool via a combination of abiotic and biotic processes. In particular, temperature-driven changes in redox conditions can lead to abiotic destabilization of Fe-organic matter (phenol) complexes, previously an underestimated decomposition pathway in peatlands, leading to increased CO2 production and accumulation of polyphenol-like compounds that could further inhibit extracellular enzyme activities and/or fuel the microbial communities with labile compounds. Further, increased temperatures can alter strategies of microbial communities for nutrient acquisition via changes in the activities of extracellular enzymes by priming SOM decomposition, leading to enhanced CO2 emission from peatlands. Therefore, coupled biotic and abiotic processes need to be incorporated into process-based climate models to predict the fate of SOM under elevated temperatures and to project the likely impacts of environmental change on northern peatlands and CO2 emissions.
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Affiliation(s)
- Roya AminiTabrizi
- Department of Environmental Science, The University of Arizona, Tucson, AZ 85721, USA
| | - Katerina Dontsova
- Department of Environmental Science, The University of Arizona, Tucson, AZ 85721, USA
| | - Nathalia Graf Grachet
- Department of Environmental Science, The University of Arizona, Tucson, AZ 85721, USA
| | - Malak M Tfaily
- Department of Environmental Science, The University of Arizona, Tucson, AZ 85721, USA; Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, WA 99354, USA.
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5
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Ashby MA, Heinemeyer A. Prescribed burning impacts on ecosystem services in the British uplands: A methodological critique of the EMBER project. J Appl Ecol 2020. [DOI: 10.1111/1365-2664.13476] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Mark A. Ashby
- Lancaster Environment Centre Lancaster University Lancaster UK
| | - Andreas Heinemeyer
- Department of Environment and Geography Stockholm Environment Institute, University of York York UK
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6
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Yu H, Zha T, Zhang X, Ma L. Vertical distribution and influencing factors of soil organic carbon in the Loess Plateau, China. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 693:133632. [PMID: 31377373 DOI: 10.1016/j.scitotenv.2019.133632] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Revised: 07/22/2019] [Accepted: 07/26/2019] [Indexed: 06/10/2023]
Abstract
Accurate analysis and evaluation of the spatial distribution and the primary factors that affect regional soil organic carbon (SOC) together make an important step in assessing carbon sequestration potential. However, little information is available on distribution of regional SOC in deep soil layers. To analyze the spatial distribution of and factors influencing SOC in a 500 cm soil profile, 1440 soil samples were collected from 90 sites on the Loess Plateau in China. The primary factors dominating the spatial distribution of SOC were quantified using principal component analysis with multiple linear regression (PCA-MLR) analysis. Results showed that the mean SOC of the 500 cm soil profile ranged from 1.20 to 3.37 g kg-1, decreasing with increasing soil depth. The SOC in the deep soil profile decreased across the types of land use in the following order: forestland > cropland > grassland. Based on the factors analyzed in this study, land use accounted for 22% of the variation in SOC and was the dominant factor controlling the spatial distribution of organic carbon in shallow soils (0-100 cm); while soil factors (including soil clay, soil water content, and soil bulk density) were dominant in deep soil layers (200-500 cm), averagely accounting for 44.3%. The SOC stock in the 0-20 cm soil layer was 1.34 kg m-2, accounting for only a small proportion (8%) of the total carbon in the entire 500 cm soil profile. SOC stock in the 200-500 cm layer was 7.62 kg m-2, accounting for 44% of the total carbon in the 0-500 cm soil profile. This study demonstrates that a large amount of organic carbon is stored in deep soil, indicating that a better understanding of the reserves and cycles of deep soil carbon is a critical factor in the effective management of terrestrial ecosystems.
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Affiliation(s)
- Haiyan Yu
- School of Environmental Science and Engineering, Tongji University, Shanghai 200092, China
| | - Tonggang Zha
- School of Soil and Water Conservation, Beijing Forestry University, Beijing 100083, China.
| | - Xiaoxia Zhang
- School of Soil and Water Conservation, Beijing Forestry University, Beijing 100083, China
| | - Limin Ma
- School of Environmental Science and Engineering, Tongji University, Shanghai 200092, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China.
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7
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Grau-Andrés R, Gray A, Davies GM, Scott EM, Waldron S. Burning increases post-fire carbon emissions in a heathland and a raised bog, but experimental manipulation of fire severity has no effect. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2019; 233:321-328. [PMID: 30584963 DOI: 10.1016/j.jenvman.2018.12.036] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Revised: 11/14/2018] [Accepted: 12/11/2018] [Indexed: 06/09/2023]
Abstract
Large amounts of carbon are stored in northern peatlands. There is concern that greater wildfire severity following projected increases in summer drought will lead to higher post-fire carbon losses. We measured soil carbon dynamics in a Calluna heathland and a raised peat bog after experimentally manipulating fire severity. A gradient of fire severity was achieved by simulating drought in 2 × 2 m plots. Ecosystem respiration (ER), net ecosystem exchange (NEE), methane (CH4) flux and concentration of dissolved organic carbon ([DOC], measured at the raised bog only) were measured for up to two years after burning. The response of these carbon fluxes to increased fire severity in drought plots was similar to plots burnt under ambient conditions associated with traditional managed burning. Averaged across all burnt plots, burning altered mean NEE from a net carbon sink at the heathland (-0.33 μmol CO2 m-2 s-1 in unburnt plots) to a carbon source (0.50 μmol m-2 s-1 in burnt plots) and at the raised bog (-0.38 and 0.16 μmol m-2 s-1, respectively). Burning also increased CH4 flux at the raised bog (from 1.16 to 25.3 nmol m-2 s-1 in the summer, when it accounted for 79% of the CO2-equivalent emission). Burning had no significant effect on soil water [DOC].
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Affiliation(s)
- Roger Grau-Andrés
- School of Geographical and Earth Sciences, University of Glasgow, Glasgow, G128QQ, UK.
| | - Alan Gray
- Centre for Ecology and Hydrology, Bush Estate, Penicuik, Midlothian, EH26 0QB, UK
| | - G Matt Davies
- School of Environment and Natural Resources, Kottman Hall, The Ohio State University, Columbus, OH, 43210, USA
| | - E Marian Scott
- School of Mathematics and Statistics, University of Glasgow, Glasgow, G128QW, UK
| | - Susan Waldron
- School of Geographical and Earth Sciences, University of Glasgow, Glasgow, G128QQ, UK
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8
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Gavazov K, Albrecht R, Buttler A, Dorrepaal E, Garnett MH, Gogo S, Hagedorn F, Mills RTE, Robroek BJM, Bragazza L. Vascular plant-mediated controls on atmospheric carbon assimilation and peat carbon decomposition under climate change. GLOBAL CHANGE BIOLOGY 2018; 24:3911-3921. [PMID: 29569798 DOI: 10.1111/gcb.14140] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2017] [Accepted: 03/06/2018] [Indexed: 06/08/2023]
Abstract
Climate change can alter peatland plant community composition by promoting the growth of vascular plants. How such vegetation change affects peatland carbon dynamics remains, however, unclear. In order to assess the effect of vegetation change on carbon uptake and release, we performed a vascular plant-removal experiment in two Sphagnum-dominated peatlands that represent contrasting stages of natural vegetation succession along a climatic gradient. Periodic measurements of net ecosystem CO2 exchange revealed that vascular plants play a crucial role in assuring the potential for net carbon uptake, particularly with a warmer climate. The presence of vascular plants, however, also increased ecosystem respiration, and by using the seasonal variation of respired CO2 radiocarbon (bomb-14 C) signature we demonstrate an enhanced heterotrophic decomposition of peat carbon due to rhizosphere priming. The observed rhizosphere priming of peat carbon decomposition was matched by more advanced humification of dissolved organic matter, which remained apparent beyond the plant growing season. Our results underline the relevance of rhizosphere priming in peatlands, especially when assessing the future carbon sink function of peatlands undergoing a shift in vegetation community composition in association with climate change.
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Affiliation(s)
- Konstantin Gavazov
- Swiss Federal Institute for Forest, Snow and Landscape Research, WSL Site Lausanne, Lausanne, Switzerland
- Laboratory of Ecological Systems ECOS, School of Architecture, Civil and Environmental Engineering ENAC, Ecole Polytechnique Fédérale de Lausanne EPFL, Lausanne, Switzerland
- Department of Ecology and Environmental Science, Climate Impacts Research Centre, Umeå University, Abisko, Sweden
| | - Remy Albrecht
- Swiss Federal Institute for Forest, Snow and Landscape Research, WSL Site Lausanne, Lausanne, Switzerland
- Laboratory of Ecological Systems ECOS, School of Architecture, Civil and Environmental Engineering ENAC, Ecole Polytechnique Fédérale de Lausanne EPFL, Lausanne, Switzerland
| | - Alexandre Buttler
- Swiss Federal Institute for Forest, Snow and Landscape Research, WSL Site Lausanne, Lausanne, Switzerland
- Laboratory of Ecological Systems ECOS, School of Architecture, Civil and Environmental Engineering ENAC, Ecole Polytechnique Fédérale de Lausanne EPFL, Lausanne, Switzerland
- Laboratoire de Chrono-Environnement, UMR CNRS 6249, UFR des Sciences et Techniques, Université de Franche-Comté, Besançon, France
| | - Ellen Dorrepaal
- Department of Ecology and Environmental Science, Climate Impacts Research Centre, Umeå University, Abisko, Sweden
| | - Mark H Garnett
- NERC Radiocarbon Facility (East Kilbride), East Kilbride, UK
| | - Sebastien Gogo
- ISTO, UMR 7327, Université d'Orléans, Orléans, France
- ISTO, UMR 7327, CNRS, Orléans, France
- ISTO, UMR 7327, BRGM, Orléans, France
| | - Frank Hagedorn
- Swiss Federal Institute for Forest, Snow and Landscape Research, WSL Site Birmensdorf, Birmensdorf, Switzerland
| | - Robert T E Mills
- Swiss Federal Institute for Forest, Snow and Landscape Research, WSL Site Lausanne, Lausanne, Switzerland
- Laboratory of Ecological Systems ECOS, School of Architecture, Civil and Environmental Engineering ENAC, Ecole Polytechnique Fédérale de Lausanne EPFL, Lausanne, Switzerland
- Lancaster Environment Centre, Lancaster University, Lancaster, UK
| | - Bjorn J M Robroek
- Swiss Federal Institute for Forest, Snow and Landscape Research, WSL Site Lausanne, Lausanne, Switzerland
- Laboratory of Ecological Systems ECOS, School of Architecture, Civil and Environmental Engineering ENAC, Ecole Polytechnique Fédérale de Lausanne EPFL, Lausanne, Switzerland
- Biological Sciences, University of Southampton, Southampton, UK
| | - Luca Bragazza
- Swiss Federal Institute for Forest, Snow and Landscape Research, WSL Site Lausanne, Lausanne, Switzerland
- Laboratory of Ecological Systems ECOS, School of Architecture, Civil and Environmental Engineering ENAC, Ecole Polytechnique Fédérale de Lausanne EPFL, Lausanne, Switzerland
- Department of Life Science and Biotechnologies, University of Ferrara, Ferrara, Italy
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9
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Järveoja J, Nilsson MB, Gažovič M, Crill PM, Peichl M. Partitioning of the net CO 2 exchange using an automated chamber system reveals plant phenology as key control of production and respiration fluxes in a boreal peatland. GLOBAL CHANGE BIOLOGY 2018; 24:3436-3451. [PMID: 29710420 DOI: 10.1111/gcb.14292] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Revised: 03/12/2018] [Accepted: 04/10/2018] [Indexed: 05/23/2023]
Abstract
The net ecosystem CO2 exchange (NEE) drives the carbon (C) sink-source strength of northern peatlands. Since NEE represents a balance between various production and respiration fluxes, accurate predictions of its response to global changes require an in depth understanding of these underlying processes. Currently, however, detailed information of the temporal dynamics as well as the separate biotic and abiotic controls of the NEE component fluxes is lacking in peatland ecosystems. In this study, we address this knowledge gap by using an automated chamber system established across natural and trenching/vegetation removal plots to partition NEE into its production (i.e., gross and net primary production; GPP and NPP) and respiration (i.e., ecosystem, heterotrophic and autotrophic respiration; ER, Rh and Ra) fluxes in a boreal peatland in northern Sweden. Our results showed that daily NEE patterns were driven by GPP while variations in ER were governed by Ra rather than Rh. Moreover, we observed pronounced seasonal shifts in the Ra/Rh and above/belowground NPP ratios throughout the main phenological phases. Generalized linear model analysis revealed that the greenness index derived from digital images (as a proxy for plant phenology) was the strongest control of NEE, GPP and NPP while explaining considerable fractions also in the variations of ER and Ra. In addition, our data exposed greater temperature sensitivity of NPP compared to Rh resulting in enhanced C sequestration with increasing temperature. Overall, our study suggests that the temporal patterns in NEE and its component fluxes are tightly coupled to vegetation dynamics in boreal peatlands and thus challenges previous studies that commonly identify abiotic factors as key drivers. These findings further emphasize the need for integrating detailed information on plant phenology into process-based models to improve predictions of global change impacts on the peatland C cycle.
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Affiliation(s)
- Järvi Järveoja
- Department of Forest Ecology & Management, Swedish University of Agricultural Sciences, Umeå, Sweden
| | - Mats B Nilsson
- Department of Forest Ecology & Management, Swedish University of Agricultural Sciences, Umeå, Sweden
| | - Michal Gažovič
- Department of Forest Ecology & Management, Swedish University of Agricultural Sciences, Umeå, Sweden
| | - Patrick M Crill
- Department of Geological Sciences, Stockholm University, Stockholm, Sweden
- Bolin Center for Climate Research, Stockholm, Sweden
| | - Matthias Peichl
- Department of Forest Ecology & Management, Swedish University of Agricultural Sciences, Umeå, Sweden
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10
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Yao X, Zhang N, Zeng H, Wang W. Effects of soil depth and plant-soil interaction on microbial community in temperate grasslands of northern China. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 630:96-102. [PMID: 29475117 DOI: 10.1016/j.scitotenv.2018.02.155] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Revised: 02/07/2018] [Accepted: 02/12/2018] [Indexed: 06/08/2023]
Abstract
Although the patterns and drivers of soil microbial community composition are well studied, little is known about the effects of plant-soil interactions and soil depth on soil microbial distribution at a regional scale. We examined 195 soil samples from 13 sites along a climatic transect in the temperate grasslands of northern China to measure the composition of and factors influencing soil microbial communities within a 1-m soil profile. Soil microbial community composition was measured using phospholipid fatty acids (PLFA) analysis. Fungi predominated in topsoil (0-10 cm) and bacteria and actinomycetes in deep soils (40-100 cm), independent of steppe types. This variation was explained by contemporary environmental factors (including above- and below-ground plant biomass, soil physicochemical and climatic factors) >58% in the 0-40 cm of soil depth, but <45% in deep soils. Interestingly, when we considered the interactive effects between plant traits (above ground biomass and root biomass) and soil factors (pH, clay content, and soil total carbon, nitrogen, phosphorous), we observed a significant interaction effect occurring at depths of 10-20 cm soil layer, due to different internal and external factors of the plant-soil system along the soil profile. These results improve understanding of the drivers of soil microbial community composition at regional scales.
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Affiliation(s)
- Xiaodong Yao
- Department of Ecology, College of Urban and Environmental Sciences and Key Laboratory for Earth Surface Processes of the Ministry of Education, Peking University, Beijing 100871, China; Peking University Shenzhen Graduate School, Shenzhen University Town, Shenzhen 518055, China.
| | - Naili Zhang
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, The Chinese Academy of Sciences, Beijing 100093, China.
| | - Hui Zeng
- Department of Ecology, College of Urban and Environmental Sciences and Key Laboratory for Earth Surface Processes of the Ministry of Education, Peking University, Beijing 100871, China; Peking University Shenzhen Graduate School, Shenzhen University Town, Shenzhen 518055, China.
| | - Wei Wang
- Department of Ecology, College of Urban and Environmental Sciences and Key Laboratory for Earth Surface Processes of the Ministry of Education, Peking University, Beijing 100871, China.
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11
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Managing peatland vegetation for drinking water treatment. Sci Rep 2016; 6:36751. [PMID: 27857210 PMCID: PMC5114669 DOI: 10.1038/srep36751] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Accepted: 10/13/2016] [Indexed: 11/15/2022] Open
Abstract
Peatland ecosystem services include drinking water provision, flood mitigation, habitat provision and carbon sequestration. Dissolved organic carbon (DOC) removal is a key treatment process for the supply of potable water downstream from peat-dominated catchments. A transition from peat-forming Sphagnum moss to vascular plants has been observed in peatlands degraded by (a) land management, (b) atmospheric deposition and (c) climate change. Here within we show that the presence of vascular plants with higher annual above-ground biomass production leads to a seasonal addition of labile plant material into the peatland ecosystem as litter recalcitrance is lower. The net effect will be a smaller litter carbon pool due to higher rates of decomposition, and a greater seasonal pattern of DOC flux. Conventional water treatment involving coagulation-flocculation-sedimentation may be impeded by vascular plant-derived DOC. It has been shown that vascular plant-derived DOC is more difficult to remove via these methods than DOC derived from Sphagnum, whilst also being less susceptible to microbial mineralisation before reaching the treatment works. These results provide evidence that practices aimed at re-establishing Sphagnum moss on degraded peatlands could reduce costs and improve efficacy at water treatment works, offering an alternative to ‘end-of-pipe’ solutions through management of ecosystem service provision.
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