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Euskirchen ES, Edgar CW, Kane ES, Waldrop MP, Neumann RB, Manies KL, Douglas TA, Dieleman C, Jones MC, Turetsky MR. Persistent net release of carbon dioxide and methane from an Alaskan lowland boreal peatland complex. GLOBAL CHANGE BIOLOGY 2024; 30:e17139. [PMID: 38273498 DOI: 10.1111/gcb.17139] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Revised: 11/20/2023] [Accepted: 12/18/2023] [Indexed: 01/27/2024]
Abstract
Permafrost degradation in peatlands is altering vegetation and soil properties and impacting net carbon storage. We studied four adjacent sites in Alaska with varied permafrost regimes, including a black spruce forest on a peat plateau with permafrost, two collapse scar bogs of different ages formed following thermokarst, and a rich fen without permafrost. Measurements included year-round eddy covariance estimates of net carbon dioxide (CO2 ), mid-April to October methane (CH4 ) emissions, and environmental variables. From 2011 to 2022, annual rainfall was above the historical average, snow water equivalent increased, and snow-season duration shortened due to later snow return. Seasonally thawed active layer depths also increased. During this period, all ecosystems acted as slight annual sources of CO2 (13-59 g C m-2 year-1 ) and stronger sources of CH4 (11-14 g CH4 m-2 from ~April to October). The interannual variability of net ecosystem exchange was high, approximately ±100 g C m-2 year-1 , or twice what has been previously reported across other boreal sites. Net CO2 release was positively related to increased summer rainfall and winter snow water equivalent and later snow return. Controls over CH4 emissions were related to increased soil moisture and inundation status. The dominant emitter of carbon was the rich fen, which, in addition to being a source of CO2 , was also the largest CH4 emitter. These results suggest that the future carbon-source strength of boreal lowlands in Interior Alaska may be determined by the area occupied by minerotrophic fens, which are expected to become more abundant as permafrost thaw increases hydrologic connectivity. Since our measurements occur within close proximity of each other (≤1 km2 ), this study also has implications for the spatial scale and data used in benchmarking carbon cycle models and emphasizes the necessity of long-term measurements to identify carbon cycle process changes in a warming climate.
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Affiliation(s)
- Eugénie S Euskirchen
- Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, Alaska, USA
- Department of Biology and Wildlife, University of Alaska Fairbanks, Fairbanks, Alaska, USA
| | - Colin W Edgar
- Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, Alaska, USA
| | - Evan S Kane
- College of Forest Resources and Environmental Science, Michigan Technological University, Houghton, Michigan, USA
- Northern Research Station, USDA Forest Service, Houghton, Michigan, USA
| | - Mark P Waldrop
- U.S. Geological Survey, Geology, Minerals, Energy, and Geophysics Science Center, Moffett Fields, Mountain View, California, USA
| | - Rebecca B Neumann
- Department of Civil and Environmental Engineering, University of Washington, Seattle, Washington, USA
| | - Kristen L Manies
- U.S. Geological Survey, Geology, Minerals, Energy, and Geophysics Science Center, Moffett Fields, Mountain View, California, USA
| | - Thomas A Douglas
- U.S. Army Cold Regions Research & Engineering Laboratory, Fort Wainwright, Fairbanks, Alaska, USA
| | - Catherine Dieleman
- Department of Integrative Biology, University of Guelph, Guelph, Ontario, Canada
| | - Miriam C Jones
- U.S. Geological Survey, Florence Bascom Geoscience Center, Reston, Virginia, USA
| | - Merritt R Turetsky
- Institute of Arctic and Alpine Research, Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, Colorado, USA
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Yang Q, Liu Z, Bai E. Comparison of carbon and nitrogen accumulation rate between bog and fen phases in a pristine peatland with the fen-bog transition. GLOBAL CHANGE BIOLOGY 2023; 29:6350-6366. [PMID: 37602716 DOI: 10.1111/gcb.16915] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/01/2023] [Accepted: 07/17/2023] [Indexed: 08/22/2023]
Abstract
Long-term carbon and nitrogen dynamics in peatlands are affected by both vegetation production and decomposition processes. Here, we examined the carbon accumulation rate (CAR), nitrogen accumulation rate (NAR) and δ13 C, δ15 N of plant residuals in a peat core dated back to ~8500 cal year BP in a temperate peatland in Northeast China. Impacted by the tephra during 1160 and 789 cal year BP and climate change, the peatland changed from a fen dominated by vascular plants to a bog dominated by Sphagnum mosses. We used the Clymo model to quantify peat addition rate and decay constant for acrotelm and catotelm layers during both bog and fen phases. Our studied peatland was dominated by Sphagnum fuscum during the bog phase (789 to -59 cal year BP) and lower accumulation rates in the acrotelm layer was found during this phase, suggesting the dominant role of volcanic eruption in the CAR of the peat core. Both mean CAR and NAR were higher during the bog phase than during the fen phase in our study, consistent with the results of the only one similar study in the literature. Because the input rate of organic matter was considered to be lower during the bog phase, the decomposition process must have been much lower during the bog phase than during the fen phase and potentially controlled CAR and NAR. During the fen phase, CAR was also lower under higher temperature and summer insolation, conditions beneficial for decomposition. δ15 N of Sphagnum hinted that nitrogen fixation had a positive effect on nitrogen accumulation, particular in recent decades. Our study suggested that decomposition is more important for carbon and nitrogen sequestration than production in peatlands in most conditions and if future climate changes or human disturbance increase decomposition rate, carbon sequestration in peatlands will be jeopardized.
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Affiliation(s)
- Qiannan Yang
- Key Laboratory of Geographical Processes and Ecological Security of Changbai Mountains, Ministry of Education, School of Geographical Sciences, Northeast Normal University, Changchun, China
| | - Ziping Liu
- Key Laboratory of Geographical Processes and Ecological Security of Changbai Mountains, Ministry of Education, School of Geographical Sciences, Northeast Normal University, Changchun, China
- Key Laboratory of Vegetation Ecology, Ministry of Education, Northeast Normal University, Changchun, China
| | - Edith Bai
- Key Laboratory of Geographical Processes and Ecological Security of Changbai Mountains, Ministry of Education, School of Geographical Sciences, Northeast Normal University, Changchun, China
- Key Laboratory of Vegetation Ecology, Ministry of Education, Northeast Normal University, Changchun, China
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Nielsen CK, Elsgaard L, Jørgensen U, Lærke PE. Soil greenhouse gas emissions from drained and rewetted agricultural bare peat mesocosms are linked to geochemistry. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 896:165083. [PMID: 37391135 DOI: 10.1016/j.scitotenv.2023.165083] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Revised: 06/19/2023] [Accepted: 06/21/2023] [Indexed: 07/02/2023]
Abstract
In view of climate considerations regarding the management of peatlands, there is a need to assess whether rewetting can mitigate greenhouse gas (GHG) emissions, and notably how site-specific soil-geochemistry will influence differences in emission magnitudes. However, there are inconsistent results regarding the correlation of soil properties with heterotrophic respiration (Rh) of carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) from bare peat. In this study, we determined 1) soil-, and site-specific geochemical components as drivers for emissions from Rh on five Danish fens and bogs, and 2) emission magnitudes under drained and rewetted conditions. For this, a mesocosm experiment was performed under equal exposure to climatic conditions and water table depths controlled to either -40 cm, or -5 cm. For the drained soils, we found that annual cumulative emissions, accounting for all three gases, were dominated by CO2, contributing with, on average, 99 % to a varying global warming potential (GWP) of 12.2-16.9 t CO2eq ha-1 yr-1. Rewetting lowered annual cumulative emissions from Rh by 3.2-5.1 t CO2eq ha-1 yr-1 for fens and bogs, respectively, despite a high variability of site-specific CH4 emissions, contributing with 0.3-3.4 t CO2 ha-1 yr-1 to the GWP. Overall, analyses using generalized additive models (GAM) showed that emission magnitudes were well explained by geochemical variables. Under drained conditions, significant soil-specific predictor variables for CO2 flux magnitudes were pH, phosphorus (P), and the soil substrate's relative water holding capacity (WHC). When rewetted, CO2 and CH4 emissions from Rh were affected by pH, WHC, as well as contents of P, total carbon and nitrogen. In conclusion, our results found the highest GHG reduction on fen peatlands, further highlighting that peat nutrient status and acidity, and the potential availability of alternative electron acceptors, might be used as proxies for prioritising peatland areas for GHG mitigation efforts by rewetting.
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Affiliation(s)
- C K Nielsen
- Department of Agroecology, Faculty of Technology, Aarhus University, Blichers Alle 20, 8830 Tjele, Denmark; CBIO, Centre for Circular Bioeconomy, Aarhus University, Denmark.
| | - L Elsgaard
- Department of Agroecology, Faculty of Technology, Aarhus University, Blichers Alle 20, 8830 Tjele, Denmark
| | - U Jørgensen
- Department of Agroecology, Faculty of Technology, Aarhus University, Blichers Alle 20, 8830 Tjele, Denmark; CBIO, Centre for Circular Bioeconomy, Aarhus University, Denmark
| | - P E Lærke
- Department of Agroecology, Faculty of Technology, Aarhus University, Blichers Alle 20, 8830 Tjele, Denmark; CBIO, Centre for Circular Bioeconomy, Aarhus University, Denmark
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Gao D, Li F, Gao W, Zeng Q, Liang H. Greenhouse gas fluxes from different types of permafrost regions in the Daxing'an Mountains, Northeast China. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023; 30:97578-97590. [PMID: 37596475 DOI: 10.1007/s11356-023-29262-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Accepted: 08/06/2023] [Indexed: 08/20/2023]
Abstract
Global warming will increase the greenhouse gas (GHG) fluxes of permafrost regions. However, little is known about the difference in GHG fluxes among different types of permafrost regions. In this study, we used the static opaque chamber and gas chromatography techniques to determine the fluxes of carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) in predominantly continuous permafrost (PCP), predominantly continuous and island permafrost (PCIP), and sparsely island permafrost (SIP) regions during the growing season. The main factors causing differences in GHG fluxes among three types of permafrost regions were also analyzed. The results showed mean CO2 fluxes in SIP were significantly higher than that in PCP and PCIP, which were 342.10 ± 11.46, 105.50 ± 10.65, and 127.15 ± 14.27 mg m-2 h-1, respectively. This difference was determined by soil temperature, soil moisture, total organic carbon (TOC), nitrate nitrogen (NO3--N), and ammonium nitrogen (NH4+-N) content. Mean CH4 fluxes were -26.47 ± 48.83 (PCP), 118.35 ± 46.93 (PCIP), and 95.52 ± 32.86 μg m-2 h-1 (SIP). Soil temperature, soil moisture, and TOC content were the key factors to determine whether permafrost regions were CH4 sources or sinks. Similarly, PCP behaved as the sink of N2O, PCIP and SIP behaved as the source of N2O. Mean N2O fluxes were -3.90 ± 1.71, 0.78 ± 1.55, and 3.78 ± 1.59 μg m-2 h-1, respectively. Soil moisture and TOC content were the main factors influencing the differences in N2O fluxes among the three permafrost regions. This study clarified and explained the differences in GHG fluxes among three types of permafrost regions, providing a data basis for such studies.
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Affiliation(s)
- Dawen Gao
- Centre for Urban Environmental Remediation, Beijing University of Civil Engineering and Architecture, Beijing, 100044, China.
- Beijing Energy Conservation & Sustainable Urban and Rural Development Provincial and Ministry Co-Construction Collaboration Innovation Center, Beijing University of Civil Engineering and Architecture, Beijing, 100044, China.
| | - Feng Li
- Centre for Urban Environmental Remediation, Beijing University of Civil Engineering and Architecture, Beijing, 100044, China
- Beijing Energy Conservation & Sustainable Urban and Rural Development Provincial and Ministry Co-Construction Collaboration Innovation Center, Beijing University of Civil Engineering and Architecture, Beijing, 100044, China
| | - Weifeng Gao
- Institute of Grassland Science, Key Laboratory of Vegetation Ecology of the Ministry of Education, Jilin Songnen Grassland Ecosystem National Observation and Research Station, Northeast Normal University, Changchun, 130024, China
| | - Qingbo Zeng
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin, 150001, China
| | - Hong Liang
- Centre for Urban Environmental Remediation, Beijing University of Civil Engineering and Architecture, Beijing, 100044, China
- Beijing Energy Conservation & Sustainable Urban and Rural Development Provincial and Ministry Co-Construction Collaboration Innovation Center, Beijing University of Civil Engineering and Architecture, Beijing, 100044, China
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Wang J, Qu YN, Evans PN, Guo Q, Zhou F, Nie M, Jin Q, Zhang Y, Zhai X, Zhou M, Yu Z, Fu QL, Xie YG, Hedlund BP, Li WJ, Hua ZS, Wang Z, Wang Y. Evidence for nontraditional mcr-containing archaea contributing to biological methanogenesis in geothermal springs. SCIENCE ADVANCES 2023; 9:eadg6004. [PMID: 37379385 DOI: 10.1126/sciadv.adg6004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Accepted: 05/24/2023] [Indexed: 06/30/2023]
Abstract
Recent discoveries of methyl-coenzyme M reductase-encoding genes (mcr) in uncultured archaea beyond traditional euryarchaeotal methanogens have reshaped our view of methanogenesis. However, whether any of these nontraditional archaea perform methanogenesis remains elusive. Here, we report field and microcosm experiments based on 13C-tracer labeling and genome-resolved metagenomics and metatranscriptomics, revealing that nontraditional archaea are predominant active methane producers in two geothermal springs. Archaeoglobales performed methanogenesis from methanol and may exhibit adaptability in using methylotrophic and hydrogenotrophic pathways based on temperature/substrate availability. A five-year field survey found Candidatus Nezhaarchaeota to be the predominant mcr-containing archaea inhabiting the springs; genomic inference and mcr expression under methanogenic conditions strongly suggested that this lineage mediated hydrogenotrophic methanogenesis in situ. Methanogenesis was temperature-sensitive , with a preference for methylotrophic over hydrogenotrophic pathways when incubation temperatures increased from 65° to 75°C. This study demonstrates an anoxic ecosystem wherein methanogenesis is primarily driven by archaea beyond known methanogens, highlighting diverse nontraditional mcr-containing archaea as previously unrecognized methane sources.
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Affiliation(s)
- Jiajia Wang
- Department of Environmental Science and Engineering, Fudan University, Shanghai 200433, China
| | - Yan-Ni Qu
- Chinese Academy of Sciences Key Laboratory of Urban Pollutant Conversion, Department of Environmental Science and Engineering, University of Science and Technology of China, Hefei 230026, China
- State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory of Plant Resources and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, China
| | - Paul N Evans
- The Australian Centre for Ecogenomics, School of Chemistry and Molecular Biosciences, University of Queensland, St Lucia 4072, QLD, Australia
| | - Qinghai Guo
- MOE Key Laboratory of Groundwater Quality and Health, State Environmental Protection Key Laboratory of Source Apportionment and Control of Aquatic Pollution, School of Environmental Studies, China University of Geosciences, Wuhan 430078, China
| | - Fengwu Zhou
- Department of Environmental Science and Engineering, Fudan University, Shanghai 200433, China
- College of Geography Science, Nanjing Normal University, Nanjing 210023, China
| | - Ming Nie
- Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, Institute of Biodiversity Science and Institute of Eco-Chongming, School of Life Sciences, Fudan University, Shanghai 200438, China
- National Observations and Research Station for Wetland Ecosystems of the Yangtze Estuary, Fudan University, Shanghai 200433, China
| | - Qusheng Jin
- Department of Earth Sciences, University of Oregon, Eugene, OR 97403, USA
| | - Yan Zhang
- Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, Institute of Biodiversity Science and Institute of Eco-Chongming, School of Life Sciences, Fudan University, Shanghai 200438, China
| | - Xiangmei Zhai
- Department of Environmental Science and Engineering, Fudan University, Shanghai 200433, China
| | - Ming Zhou
- Department of Environmental Science and Engineering, Fudan University, Shanghai 200433, China
| | - Zhiguo Yu
- School of Hydrology and Water Resources, Nanjing University of Information Science and Technology, Nanjing 210044, China
| | - Qing-Long Fu
- MOE Key Laboratory of Groundwater Quality and Health, State Environmental Protection Key Laboratory of Source Apportionment and Control of Aquatic Pollution, School of Environmental Studies, China University of Geosciences, Wuhan 430078, China
| | - Yuan-Guo Xie
- Chinese Academy of Sciences Key Laboratory of Urban Pollutant Conversion, Department of Environmental Science and Engineering, University of Science and Technology of China, Hefei 230026, China
| | - Brian P Hedlund
- School of Life Sciences, University of Nevada Las Vegas, Las Vegas, NV 89154, USA
- Nevada Institute of Personalized Medicine, University of Nevada Las Vegas, Las Vegas, NV 89154, USA
| | - Wen-Jun Li
- State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory of Plant Resources and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, China
| | - Zheng-Shuang Hua
- Chinese Academy of Sciences Key Laboratory of Urban Pollutant Conversion, Department of Environmental Science and Engineering, University of Science and Technology of China, Hefei 230026, China
| | - Zimeng Wang
- Department of Environmental Science and Engineering, Fudan University, Shanghai 200433, China
- National Observations and Research Station for Wetland Ecosystems of the Yangtze Estuary, Fudan University, Shanghai 200433, China
- Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China
| | - Yanxin Wang
- MOE Key Laboratory of Groundwater Quality and Health, State Environmental Protection Key Laboratory of Source Apportionment and Control of Aquatic Pollution, School of Environmental Studies, China University of Geosciences, Wuhan 430078, China
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Chen X, Xue D, Wang Y, Qiu Q, Wu L, Wang M, Liu J, Chen H. Variations in the archaeal community and associated methanogenesis in peat profiles of three typical peatland types in China. ENVIRONMENTAL MICROBIOME 2023; 18:48. [PMID: 37280702 DOI: 10.1186/s40793-023-00503-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Accepted: 05/15/2023] [Indexed: 06/08/2023]
Abstract
BACKGROUND Peatlands contain about 500 Pg of carbon worldwide and play a dual role as both a carbon sink and an important methane (CH4) source, thereby potentially influencing climate change. However, systematic studies on peat properties, microorganisms, methanogenesis, and their interrelations in peatlands remain limited, especially in China. Therefore, the present study aims to investigate the physicochemical properties, archaeal community, and predominant methanogenesis pathways in three typical peatlands in China, namely Hani (H), Taishanmiao (T), and Ruokeba (R) peatlands, and quantitively determine their CH4 production potentials. RESULTS These peatlands exhibited high water content (WC) and total carbon content (TC), as well as low pH values. In addition, R exhibited a lower dissolved organic carbon concentration (DOC), as well as higher total iron content (TFe) and pH values compared to those observed in T. There were also clear differences in the archaeal community between the three peatlands, especially in the deep peat layers. The average relative abundance of the total methanogens ranged from 10 to 12%, of which Methanosarcinales and Methanomicrobiales were the most abundant in peat samples (8%). In contrast, Methanobacteriales were mainly distributed in the upper peat layer (0-40 cm). Besides methanogens, Marine Benthic Group D/Deep-Sea Hydrothermal Vent Euryarchaeotic Group 1 (MBG-D/DHVEG-1), Nitrosotaleales, and several other orders of Bathyarchaeota also exhibited high relative abundances, especially in T. This finding might be due to the unique geological conditions, suggesting high archaeal diversity in peatlands. In addition, the highest and lowest CH4 production potentials were 2.38 and 0.22 μg g-1 d-1 in H and R, respectively. The distributions of the dominant methanogens were consistent with the respective methanogenesis pathways in the three peatlands. The pH, DOC, and WC were strongly correlated with CH4 production potentials. However, no relationship was found between CH4 production potential and methanogens, suggesting that CH4 production in peatlands may not be controlled by the relative abundance of methanogens. CONCLUSIONS The results of the present study provide further insights into CH4 production in peatlands in China, highlighting the importance of the archaeal community and peat physicochemical properties for studies on methanogenesis in distinct types of peatlands.
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Affiliation(s)
- Xuhui Chen
- CAS Key Laboratory of Mountain Ecological Restoration and Bioresource Utilization and Ecological Restoration Biodiversity Conservation Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, No. 9, Section 4, South Renmin Road, Chengdu, 610041, China
- Zoige Peatland and Global Change Research Station, Chinese Academy of Sciences, Hongyuan, 624400, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Dan Xue
- CAS Key Laboratory of Mountain Ecological Restoration and Bioresource Utilization and Ecological Restoration Biodiversity Conservation Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, No. 9, Section 4, South Renmin Road, Chengdu, 610041, China.
- Zoige Peatland and Global Change Research Station, Chinese Academy of Sciences, Hongyuan, 624400, China.
| | - Yue Wang
- CAS Key Laboratory of Mountain Ecological Restoration and Bioresource Utilization and Ecological Restoration Biodiversity Conservation Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, No. 9, Section 4, South Renmin Road, Chengdu, 610041, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Qing Qiu
- CAS Key Laboratory of Mountain Ecological Restoration and Bioresource Utilization and Ecological Restoration Biodiversity Conservation Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, No. 9, Section 4, South Renmin Road, Chengdu, 610041, China
- Zoige Peatland and Global Change Research Station, Chinese Academy of Sciences, Hongyuan, 624400, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Lin Wu
- School of Forestry and Horticulture, Hubei Minzu University, Enshi, 445000, Hubei, China
| | - Meng Wang
- State Environmental Protection Key Laboratory of Wetland Ecology and Vegetation Restoration, Institute for Peat and Mire Research, Northeast Normal University, Changchun, 130024, China
| | - Jiawen Liu
- SQE Department, COFCO Coca-Cola Beverages (Sichuan) Company Limited, Chengdu, 610500, China
| | - Huai Chen
- CAS Key Laboratory of Mountain Ecological Restoration and Bioresource Utilization and Ecological Restoration Biodiversity Conservation Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, No. 9, Section 4, South Renmin Road, Chengdu, 610041, China.
- Zoige Peatland and Global Change Research Station, Chinese Academy of Sciences, Hongyuan, 624400, China.
- CAS Center for Excellence in Tibetan Plateau Earth Sciences, Chinese Academy of Sciences (CAS), Beijing, 100101, China.
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Kolari THM, Tahvanainen T. Inference of future bog succession trajectory from spatial chronosequence of changing aapa mires. Ecol Evol 2023; 13:e9988. [PMID: 37082320 PMCID: PMC10111175 DOI: 10.1002/ece3.9988] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Revised: 03/16/2023] [Accepted: 03/24/2023] [Indexed: 04/22/2023] Open
Abstract
Climate change-driven vegetation changes can alter the ecosystem functions of northern peatlands. Several case studies have documented fen-to-bog transition (FBT) over recent decades, which can have major implications, as increased bog growth would likely cause cooling feedback. However, studies beyond individual cases are missing to infer if a common trajectory or many alternatives of FBT are in progress. We explored plant community and hydrology patterns during FBT of 23 boreal aapa mire complexes in Finland. We focused on mires where comparisons of historical (1940-1970) and new (2017-2019) aerial photographs indicated an expansion of Sphagnum-dominated zones. Vegetation plot and water chemistry data were collected from string-flark fens, transition zones with indications of Sphagnum increase, and bog zones; thus, in a chronosequence with a decadal time span. We ask, is there a common trajectory or many alternatives of FBT in progress, and what are the main characteristics (species and traits) of transitional plant communities? We found a pattern of fen-bog transitions via an increase in Sphagnum sect. Cuspidata (mainly S. majus and S. balticum), indicating a consistently high water table. Indicators only of transitional communities were scarce (Sphagnum lindbergii), but FBT had apparently facilitated shallow-rooted aerenchymatous vascular plants, especially Scheuchzeria palustris. Water pH consistently reflected the chronosequence with averages of 4.2, 3.9, and 3.8, from fen to transition and bog zones. Due to weak minerotrophy of string-flark fens, species richness increased towards bogs, but succession led to reduced beta diversity and homogenization among bog sites. Decadal chronosequence suggested a future fen-bog transition through a wet phase, instead of a drying trend. Transitional poor-fen vegetation was characterized by the abundance of Sphagnum lindbergii, S. majus, and Scheuchzeria palustris. Sphagnum mosses likely benefit from longer growing seasons and consistently wet and acidic conditions of aapa mires.
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Affiliation(s)
- Tiina H. M. Kolari
- Department of Environmental and Biological SciencesUniversity of Eastern FinlandP.O. Box 111JoensuuFI‐80101Finland
| | - Teemu Tahvanainen
- Department of Environmental and Biological SciencesUniversity of Eastern FinlandP.O. Box 111JoensuuFI‐80101Finland
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Zhu J, Li Y, Huang M, Xu D, Zhang Y, Zhou Q, Wu Z, Wang C. Restoration effects of submerged macrophytes on methane production and oxidation potential of lake sediments. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 866:161218. [PMID: 36584953 DOI: 10.1016/j.scitotenv.2022.161218] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Revised: 12/21/2022] [Accepted: 12/23/2022] [Indexed: 06/17/2023]
Abstract
The restoration of submerged macrophytes is an important step in lake ecosystem restoration, during which artificially assisted measures have been widely used for macrophyte recolonization. Compared with natural restoration, the impact of artificially assisted methods on methane (CH4) production and oxidation of lake sediments remains unclear. Therefore, after the restoration of submerged macrophytes in some parts of West Lake (Hangzhou, China), sediment samples from West Lake were collected according to restoration methods and plant coverage. The CH4 production potential, oxidation potential, and microbial community structure in the sediment were discussed through whole-lake sample analysis and resampling verification from typical lake areas. From the analysis of the whole lake, the average daily CH4 production potential (ADP) of artificially restored lake areas (0.12 μg g-1 d-1) was significantly lower than that of the naturally restored lake areas (0.52 μg g-1 d-1). From the resampling analysis of typical lake areas, the ADP of naturally restored lake areas was 1.8 times that of artificially restored lake areas (P < 0.01). Although there was no significant difference in the CH4 oxidation potential between the two restoration methods, the presence of submerged macrophytes significantly increased the abundance of the dominant methanotroph Methylocaldum in the sediment, and the rate of increase in the abundance of the dominant methanotroph Methylosinus was significantly higher in artificially assisted restoration than in natural restoration. This study revealed that the artificially assisted restoration of submerged macrophytes reduced the potential for CH4 production and increased the abundance of dominant methanotrophs in the lake sediment, which would be beneficial for the reduction of CH4 emissions during lake ecological restoration and environmental management.
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Affiliation(s)
- Jianglong Zhu
- Faculty of Resources and Environmental Science, Hubei University, No. 368 Youyi Avenue, Wuchang District, Wuhan 430062, China; Hubei Key Laboratory of Regional Development and Environmental Response, Hubei University, No. 368 Youyi Avenue, Wuchang District, Wuhan 430062, China
| | - Yahua Li
- China University of Geosciences, No. 388 Lumo Road, Hongshan District, Wuhan 430074, China
| | - Minghui Huang
- China University of Geosciences, No. 388 Lumo Road, Hongshan District, Wuhan 430074, China
| | - Dong Xu
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, No. 7 Donghu South Road, Wuchang District, Wuhan 430072, China
| | - Yi Zhang
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, No. 7 Donghu South Road, Wuchang District, Wuhan 430072, China
| | - Qiaohong Zhou
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, No. 7 Donghu South Road, Wuchang District, Wuhan 430072, China
| | - Zhenbin Wu
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, No. 7 Donghu South Road, Wuchang District, Wuhan 430072, China
| | - Chuan Wang
- Faculty of Resources and Environmental Science, Hubei University, No. 368 Youyi Avenue, Wuchang District, Wuhan 430062, China; Hubei Key Laboratory of Regional Development and Environmental Response, Hubei University, No. 368 Youyi Avenue, Wuchang District, Wuhan 430062, China; State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, No. 7 Donghu South Road, Wuchang District, Wuhan 430072, China.
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Biotic and Abiotic Control Over Diurnal CH4 Fluxes in a Temperate Transitional Poor Fen Ecosystem. Ecosystems 2022. [DOI: 10.1007/s10021-022-00809-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
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Abstract
Wetlands are the major natural source of methane, an important greenhouse gas. The sulfur and methane cycles in wetlands are linked—e.g., a strong sulfur cycle can inhibit methanogenesis. Although there has historically been a clear distinction drawn between methane and sulfur oxidizers, here, we isolated a methanotroph that also performed respiratory oxidization of sulfur compounds. We experimentally demonstrated that thiotrophy and methanotrophy are metabolically compatible, and both metabolisms could be expressed simultaneously in a single microorganism. These findings suggest that mixotrophic methane/sulfur-oxidizing bacteria are a previously overlooked component of environmental methane and sulfur cycles. This creates a framework for a better understanding of these redox cycles in natural and engineered wetlands. Natural and anthropogenic wetlands are major sources of the atmospheric greenhouse gas methane. Methane emissions from wetlands are mitigated by methanotrophic bacteria at the oxic–anoxic interface, a zone of intense redox cycling of carbon, sulfur, and nitrogen compounds. Here, we report on the isolation of an aerobic methanotrophic bacterium, ‘Methylovirgula thiovorans' strain HY1, which possesses metabolic capabilities never before found in any methanotroph. Most notably, strain HY1 is the first bacterium shown to aerobically oxidize both methane and reduced sulfur compounds for growth. Genomic and proteomic analyses showed that soluble methane monooxygenase and XoxF-type alcohol dehydrogenases are responsible for methane and methanol oxidation, respectively. Various pathways for respiratory sulfur oxidation were present, including the Sox–rDsr pathway and the S4I system. Strain HY1 employed the Calvin–Benson–Bassham cycle for CO2 fixation during chemolithoautotrophic growth on reduced sulfur compounds. Proteomic and microrespirometry analyses showed that the metabolic pathways for methane and thiosulfate oxidation were induced in the presence of the respective substrates. Methane and thiosulfate could therefore be independently or simultaneously oxidized. The discovery of this versatile bacterium demonstrates that methanotrophy and thiotrophy are compatible in a single microorganism and underpins the intimate interactions of methane and sulfur cycles in oxic–anoxic interface environments.
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Abstract
AbstractWe investigated recent changes in spatial patterning of fen and bog zones in five boreal aapa mire complexes (mixed peatlands with patterned fen and bog parts) in a multiproxy study. Comparison of old (1940–1970s) and new aerial images revealed decrease of flarks (wet hollows) in patterned fens by 33–63% in middle boreal and 16–42% in northern boreal sites, as lawns of bog Sphagnum mosses expanded over fens. Peat core transects across transformed areas were used to verify the remote sensing inference with stratigraphic analyses of macrofossils, hyperspectral imaging, and age-depth profiles derived from 14C AMS dating and pine pollen density. The transect data revealed that the changes observed by remote sensing during past decades originated already from the end of the Little Ice Age (LIA) between 1700–1850 CE in bog zones and later in the flarks of fen zones. The average lateral expansion rate of bogs over fen zones was 0.77 m y−1 (range 0.19–1.66) as estimated by remote sensing, and 0.71 m y−1 (range 0.13–1.76) based on peat transects. The contemporary plant communities conformed to the macrofossil communities, and distinct vegetation zones were recognized as representing recently changed areas. The fen-bog transition increased the apparent carbon accumulation, but it can potentially threaten fen species and habitats. These observations indicate that rapid lateral bog expansion over aapa mires may be in progress, but more research is needed to reveal if ongoing fen-bog transitions are a commonplace phenomenon in northern mires.
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Kolari THM, Sallinen A, Wolff F, Kumpula T, Tolonen K, Tahvanainen T. Ongoing Fen–Bog Transition in a Boreal Aapa Mire Inferred from Repeated Field Sampling, Aerial Images, and Landsat Data. Ecosystems 2021. [DOI: 10.1007/s10021-021-00708-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
AbstractNorthern aapa mire complexes are characterized by patterned fens with flarks (wet fen surfaces) and bog zone margins with Sphagnum moss cover. Evidence exists of a recent increase in Sphagnum over fens that can alter ecosystem functions. Contrast between flarks and Sphagnum moss cover may enable remote sensing of these changes with satellite proxies. We explored recent changes in hydro-morphological patterns and vegetation in a south-boreal aapa mire in Finland and tested the performance of Landsat bands and indices in detecting Sphagnum increase in aapa mires. We combined aerial image analysis and vegetation survey, repeated after 60 years, to support Landsat satellite image analysis. Aerial image analysis revealed a decrease in flark area by 46% between 1947 and 2019. Repeated survey showed increase in Sphagnum mosses (S. pulchrum, S. papillosum) and deep-rooted vascular plants (Menyanthes trifoliata, Carex rostrata). A supervised classification of high-resolution UAV image recognized the legacy of infilled flarks in the patterning of Sphagnum carpets. Among Landsat variables, all separate spectral bands, the Green Difference Vegetation Index (GDVI), and the Automated Water Extraction Index (AWEI) correlated with the flark area. Between 1985 and 2020, near-infrared (NIR) and GDVI increased in the central flark area, and AWEI decreased throughout the mire area. In aapa mire complexes, flark fen and Sphagnum bog zones have contrasting Landsat NIR reflectance, and NIR band is suggested for monitoring changes in flarks. The observed increase in Sphagnum mosses supports the interpretation of ongoing fen–bog transitions in Northern European aapa mires, indicating significant ecosystem-scale changes.
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