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Guo J, Feng H, Peng C, Du J, Wang W, Kneeshaw D, Pan C, Roberge G, Feng L, Chen A. Fire effects on soil CH 4 and N 2O fluxes across terrestrial ecosystems. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 948:174708. [PMID: 39032756 DOI: 10.1016/j.scitotenv.2024.174708] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2024] [Revised: 07/08/2024] [Accepted: 07/09/2024] [Indexed: 07/23/2024]
Abstract
Fire, as a natural disturbance, significantly shapes and influences the functions and services of terrestrial ecosystems via biotic and abiotic processes. Comprehending the influence of fire on soil greenhouse gas dynamics is crucial for understanding the feedback mechanisms between fire disturbances and climate change. Despite work on CO2 fluxes, there is a large uncertainty as to whether and how soil CH4 and N2O fluxes change in response to fire disturbance in terrestrial ecosystems. To narrow this knowledge gap, we performed a meta-analysis synthesizing 3615 paired observations from 116 global studies. Our findings revealed that fire increased global soil CH4 uptake in uplands by 23.2 %, soil CH4 emissions from peatlands by 74.7 %, and soil N2O emissions in terrestrial ecosystems (including upland and peatland) by 18.8 %. Fire increased soil CH4 uptake in boreal, temperate, and subtropical forests by 20.1 %, 38.8 %, and 30.2 %, respectively, and soil CH4 emissions in tropical forests by 193.3 %. Additionally, fire negatively affected soil total carbon (TC; -10.3 %), soil organic carbon (SOC; -15.6 %), microbial biomass carbon (MBC; -44.8 %), dissolved organic carbon (DOC; -27 %), microbial biomass nitrogen (MBN; -24.7 %), soil water content (SWC; -9.2 %), and water table depth (WTD; -68.2 %). Conversely, the fire increased soil bulk density (BD; +10.8 %), ammonium nitrogen (NH4+-N; +46 %), nitrate nitrogen (NO3--N; +54 %), pH (+4.4 %), and soil temperature (+15.4 %). Our meta-regression analysis showed that the positive effects of fire on soil CH4 and N2O emissions were significantly positively correlated with mean annual temperature (MAT) and mean annual precipitation (MAP), indicating that climate warming will amplify the positive effects of fire disturbance on soil CH4 and N2O emissions. Taken together, since higher future temperatures are likely to prolong the fire season and increase the potential of fires, this could lead to positive feedback between warming, fire events, CH4 and N2O emissions, and future climate change.
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Affiliation(s)
- Jiahuan Guo
- Key Laboratory of Ministry of Education for Genetics and Germplasm Innovation of Tropical Special Trees and Ornamental Plants, School of Tropical Agriculture and Forestry (School of Agricultural and Rural Affairs, School of Rural Revitalization), Hainan University, Haikou, Hainan 570228, China
| | - Huili Feng
- Key Laboratory of Ministry of Education for Genetics and Germplasm Innovation of Tropical Special Trees and Ornamental Plants, School of Tropical Agriculture and Forestry (School of Agricultural and Rural Affairs, School of Rural Revitalization), Hainan University, Haikou, Hainan 570228, China.
| | - Changhui Peng
- Department of Biological Sciences, University of Quebec at Montreal, Montreal, Quebec H3C 3P8, Canada; College of Geographic Science, Hunan Normal University, Changsha, Hunan 410081, China
| | - Juan Du
- Yangtze River Fisheries Research Institute, Chinese Academy of Fishery Science, Wuhan, Hubei 430223, China
| | - Weifeng Wang
- Co-Innovation Center for Sustainable Forestry in Southern China, College of Ecology and Environment, Nanjing Forestry University, Nanjing, Jiangsu 210037, China
| | - Daniel Kneeshaw
- Department of Biological Sciences, University of Quebec at Montreal, Montreal, Quebec H3C 3P8, Canada
| | - Chang Pan
- College of Life Sciences, Anqing Normal University, Anqing, Anhui 246011, China
| | - Gabrielle Roberge
- Department of Biological Sciences, University of Quebec at Montreal, Montreal, Quebec H3C 3P8, Canada
| | - Lei Feng
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, Jiangsu 210023, China
| | - Anping Chen
- Department of Biology and Graduate Degree Program in Ecology, Colorado State University, Fort Collins, CO 80523, USA
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Zhou X, Xiao W, Cheng L, Smaill SJ, Peng S. Unveiling the impact of soil methane sink on atmospheric methane concentrations in 2020. GLOBAL CHANGE BIOLOGY 2024; 30:e17381. [PMID: 38923235 DOI: 10.1111/gcb.17381] [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: 11/14/2023] [Revised: 02/15/2024] [Accepted: 05/15/2024] [Indexed: 06/28/2024]
Abstract
In 2020, anthropogenic methane (CH4) emissions decreased due to COVID-19 containment policies, but there was a substantial increase in the concentration of atmospheric CH4. Previous research suggested that this abnormal increase was linked to higher wetland CH4 emissions and a decrease in the atmospheric CH4 sink. However, the impact of changes in the soil CH4 sink remained unknown. To address this, we utilized a process-based model to quantify alterations in the soil CH4 sink of terrestrial ecosystems between 2019 and 2020. By implementing the model with various datasets, we consistently observed an increase in the global soil CH4 sink, reaching up to 0.35 ± 0.06 Tg in 2020 compared to 2019. This increase was primarily attributed to warmer soil temperatures in northern high latitudes. Our results emphasize the importance of considering the CH4 sink in terrestrial ecosystems, as neglecting this component can lead to an underestimation of both emission increases and reductions in atmospheric CH4 sink capacity. Furthermore, these findings highlight the potential role of increased soil warmth in terrestrial ecosystems in slowing the growth of CH4 concentrations in the atmosphere.
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Affiliation(s)
- Xiaoqi Zhou
- Zhejiang Tiantong Forest Ecosystem National Observation and Research Station, School of Ecological and Environmental Sciences, East China Normal University, Shanghai, China
| | - Wensheng Xiao
- Zhejiang Tiantong Forest Ecosystem National Observation and Research Station, School of Ecological and Environmental Sciences, East China Normal University, Shanghai, China
| | - Li Cheng
- Zhejiang Tiantong Forest Ecosystem National Observation and Research Station, School of Ecological and Environmental Sciences, East China Normal University, Shanghai, China
| | | | - Shushi Peng
- College of Urban and Environmental Sciences, Peking University, Beijing, China
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Xiong J, Wang G, Sun X, Hu Z, Li Y, Sun J, Zhang W, Sun S. Effects of litter and root inputs on soil CH 4 uptake rates and associated microbial abundances in natural temperature subalpine forests. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 912:168730. [PMID: 38007118 DOI: 10.1016/j.scitotenv.2023.168730] [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: 04/26/2023] [Revised: 11/17/2023] [Accepted: 11/18/2023] [Indexed: 11/27/2023]
Abstract
Climate change altered the quantities of aboveground plant litter and root inputs, but the effects on soil CH4 uptake rates and underlying mechanisms remain unclear. To investigate these factors, a three-year detritus input and removal treatment (DIRT) study including six treatments (namely, CK, control; NL, litter removal; DL, double litter; NR, root exclusion; NRNL, root exclusion plus litter removal; and NRDL, root exclusion plus double litter) was conducted in broadleaf and coniferous forest subalpine forest ecosystems. The results showed that both the subalpine forest soils acted as sink for atmospheric CH4 across all treatments, while the broadleaf forest had consistently higher CH4 uptake rates than the coniferous forest. Based on the annual mean values, root exclusion (NR, NRNL and NRDL) significantly decreased soil CH4 uptake rates by 35.9 %, 31.0 % and 43.4 % in the broadleaf forest and 36.7 %, 31.9 % and 40.6 % in the coniferous forest compared with CK treatments, respectively. Meanwhile, the mean soil CH4 uptake rates were significantly reduced by 23.6 % and 17.3 % in the broadleaf forest and the coniferous forest under the DL treatments, respectively; nevertheless, the NL treatment significantly increased soil CH4 uptake rates by 19.68 % and 14.4 %, respectively. The results clearly demonstrated that root exclusion exerted a greater influence on soil CH4 uptake rates than plant litter manipulations. Correlation and redundancy analysis (RDA) revealed that the separation of root exclusion treatments from aboveground plant litter manipulations was based on higher soil water content, NH4+-N and NO3--N concentrations, and lower DOC (dissolved organic carbon) concentrations and methanotroph pmoA gene abundance. The results suggest that future alterations in aboveground plant litter and root input, particularly a reduction in root input, can exert a stronger influence on regulating soil CH4 uptake than aboveground litter manipulations in subalpine forests with cold and humid climatic conditions in response to future climate scenarios.
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Affiliation(s)
- Jia Xiong
- Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu 610041, China; University of Chinese Academy of Sciences, Beijing 100049, China; State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu 610065, China
| | - Genxu Wang
- State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu 610065, China
| | - Xiangyang Sun
- State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu 610065, China
| | - Zhaoyong Hu
- State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu 610065, China
| | - Yang Li
- State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu 610065, China
| | - Juying Sun
- State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu 610065, China
| | - Wei Zhang
- School of Agriculture, Forestry and Food Engineering, Yibin University, Yibin 644000, China
| | - Shouqin Sun
- State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu 610065, China.
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Lee J, Oh Y, Lee ST, Seo YO, Yun J, Yang Y, Kim J, Zhuang Q, Kang H. Soil organic carbon is a key determinant of CH 4 sink in global forest soils. Nat Commun 2023; 14:3110. [PMID: 37253779 DOI: 10.1038/s41467-023-38905-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Accepted: 05/16/2023] [Indexed: 06/01/2023] Open
Abstract
Soil organic carbon (SOC) is a primary regulator of the forest-climate feedback. However, its indicative capability for the soil CH4 sink is poorly understood due to the incomplete knowledge of the underlying mechanisms. Therefore, SOC is not explicitly included in the current model estimation of the global forest CH4 sink. Here, using in-situ observations, global meta-analysis, and process-based modeling, we provide evidence that SOC constitutes an important variable that governs the forest CH4 sink. We find that a CH4 sink is enhanced with increasing SOC content on regional and global scales. The revised model with SOC function better reproduces the field observation and estimates a 39% larger global forest CH4 sink (24.27 Tg CH4 yr-1) than the model without considering SOC effects (17.46 Tg CH4 yr-1). This study highlights the role of SOC in the forest CH4 sink, which shall be factored into future global CH4 budget quantification.
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Affiliation(s)
- Jaehyun Lee
- School of Civil and Environmental Engineering, Yonsei University, Seoul, 03722, Korea
| | - Youmi Oh
- Global Monitoring Laboratory, National Oceanic and Atmospheric Administration, Boulder, CO, USA
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, USA
| | - Sang Tae Lee
- Forest Technology and Management Research Center, National Institute of Forest Science, Gyeonggi, Korea
| | - Yeon Ok Seo
- Warm Temperate and Subtropical Forest Research Center, National Institute of Forest Science, Jeju, Korea
| | - Jeongeun Yun
- School of Civil and Environmental Engineering, Yonsei University, Seoul, 03722, Korea
| | - Yerang Yang
- School of Civil and Environmental Engineering, Yonsei University, Seoul, 03722, Korea
| | - Jinhyun Kim
- School of Civil and Environmental Engineering, Yonsei University, Seoul, 03722, Korea
- Division of Life Sciences, Korea Polar Research Institute, Incheon, 21990, Korea
| | - Qianlai Zhuang
- Department of Earth, Atmospheric, and Planetary Sciences, Purdue University, West Lafayette, IN, USA
| | - Hojeong Kang
- School of Civil and Environmental Engineering, Yonsei University, Seoul, 03722, Korea.
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Feng Z, Wang L, Wan X, Yang J, Peng Q, Liang T, Wang Y, Zhong B, Rinklebe J. Responses of soil greenhouse gas emissions to land use conversion and reversion-A global meta-analysis. GLOBAL CHANGE BIOLOGY 2022; 28:6665-6678. [PMID: 35989422 DOI: 10.1111/gcb.16370] [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: 07/08/2022] [Accepted: 07/27/2022] [Indexed: 06/15/2023]
Abstract
Exploring the responses of greenhouse gas (GHG) emissions to land use conversion or reversion is significant for taking effective land use measures to alleviate global warming. A global meta-analysis was conducted to analyze the responses of carbon dioxide (CO2 ), methane (CH4 ), and nitrous oxide (N2 O) emissions to land use conversion or reversion, and determine their temporal evolution, driving factors, and potential mechanisms. Our results showed that CH4 and N2 O responded positively to land use conversion while CO2 responded negatively to the changes from natural herb and secondary forest to plantation. By comparison, CH4 responded negatively to land use reversion and N2 O also showed negative response to the reversion from agricultural land to forest. The conversion of land use weakened the function of natural forest and grassland as CH4 sink and the artificial nitrogen (N) addition for plantation increased N source for N2 O release from soil, while the reversion of land use could alleviate them to some degree. Besides, soil carbon would impact CO2 emission for a long time after land use conversion, and secondary forest reached the CH4 uptake level similar to that of primary forest after over 40 years. N2 O responses had negative relationships with time interval under the conversions from forest to plantation, secondary forest, and pasture. In addition, meta-regression indicated that CH4 had correlations with several environmental variables, and carbon-nitrogen ratio had contrary relationships with N2 O emission responses to land use conversion and reversion. And the importance of driving factors displayed that CO2 , CH4 , and N2 O response to land use conversion and reversion was easily affected by NH4 + and soil moisture, mean annual temperature and NO3 - , total nitrogen and mean annual temperature, respectively. This study would provide enlightenments for scientific land management and reduction of GHG emissions.
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Affiliation(s)
- Zhaohui Feng
- Key Laboratory of Land Surface Pattern and Simulation, Institute of Geographical Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, China
| | - Lingqing Wang
- Key Laboratory of Land Surface Pattern and Simulation, Institute of Geographical Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, China
| | - Xiaoming Wan
- Key Laboratory of Land Surface Pattern and Simulation, Institute of Geographical Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, China
| | - Jun Yang
- Key Laboratory of Land Surface Pattern and Simulation, Institute of Geographical Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, China
| | - Qin Peng
- Key Laboratory of Land Surface Pattern and Simulation, Institute of Geographical Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, China
| | - Tao Liang
- Key Laboratory of Land Surface Pattern and Simulation, Institute of Geographical Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, China
| | - Yazhu Wang
- Key Laboratory of Watershed Geographic Sciences, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, China
| | - Buqing Zhong
- South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China
| | - Jörg Rinklebe
- School of Architecture and Civil Engineering, Institute of Foundation Engineering, Water- and Waste-Management, Soil- and Groundwater-Management, University of Wuppertal, Wuppertal, Germany
- International Research Centre of Nanotechnology for Himalayan Sustainability (IRCNHS), Shoolini University, Solan, Himachal Pradesh, India
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Atmospheric Methane Consumption and Methanotroph Communities in West Siberian Boreal Upland Forest Ecosystems. FORESTS 2021. [DOI: 10.3390/f12121738] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Upland forest ecosystems are recognized as net sinks for atmospheric methane (CH4), one of the most impactful greenhouse gases. Biological methane uptake in these ecosystems occurs due to the activity of aerobic methanotrophic bacteria. Russia hosts one-fifth of the global forest area, with the most extensive forest landscapes located in West Siberia. Here, we report seasonal CH4 flux measurements conducted in 2018 in three types of stands in West Siberian middle taiga–Siberian pine, Aspen, and mixed forests. High rates of methane uptake of up to −0.184 mg CH4 m−2 h−1 were measured by a static chamber method, with an estimated total growing season consumption of 4.5 ± 0.5 kg CH4 ha−1. Forest type had little to no effect on methane fluxes within each season. Soil methane oxidation rate ranged from 0 to 8.1 ng CH4 gDW−1 h−1 and was negatively related to water-filled pore space. The microbial soil communities were dominated by the Alpha- and Gammaproteobacteria, Acidobacteriota and Actinobacteriota. The major group of 16S rRNA gene reads from methanotrophs belonged to uncultivated Beijerinckiaceae bacteria. Molecular identification of methanotrophs based on retrieval of the pmoA gene confirmed that Upland Soil Cluster Alpha was the major bacterial group responsible for CH4 oxidation.
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Holmberg M, Akujärvi A, Anttila S, Autio I, Haakana M, Junttila V, Karvosenoja N, Kortelainen P, Mäkelä A, Minkkinen K, Minunno F, Rankinen K, Ojanen P, Paunu VV, Peltoniemi M, Rasilo T, Sallantaus T, Savolahti M, Tuominen S, Tuominen S, Vanhala P, Forsius M. Sources and sinks of greenhouse gases in the landscape: Approach for spatially explicit estimates. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 781:146668. [PMID: 33794457 DOI: 10.1016/j.scitotenv.2021.146668] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Revised: 03/14/2021] [Accepted: 03/17/2021] [Indexed: 06/12/2023]
Abstract
Climate change mitigation is a global response that requires actions at the local level. Quantifying local sources and sinks of greenhouse gases (GHG) facilitate evaluating mitigation options. We present an approach to collate spatially explicit estimated fluxes of GHGs (carbon dioxide, methane and nitrous oxide) for main land use sectors in the landscape, to aggregate, and to calculate the net emissions of an entire region. Our procedure was developed and tested in a large river basin in Finland, providing information from intensively studied eLTER research sites. To evaluate the full GHG balance, fluxes from natural ecosystems (lakes, rivers, and undrained mires) were included together with fluxes from anthropogenic activities, agriculture and forestry. We quantified the fluxes based on calculations with an anthropogenic emissions model (FRES) and a forest growth and carbon balance model (PREBAS), as well as on emission coefficients from the literature regarding emissions from lakes, rivers, undrained mires, peat extraction sites and cropland. Spatial data sources included CORINE land use data, soil map, lake and river shorelines, national forest inventory data, and statistical data on anthropogenic activities. Emission uncertainties were evaluated with Monte Carlo simulations. Artificial surfaces were the most emission intensive land-cover class. Lakes and rivers were about as emission intensive as arable land. Forests were the dominant land cover in the region (66%), and the C sink of the forests decreased the total emissions of the region by 72%. The region's net emissions amounted to 4.37 ± 1.43 Tg CO2-eq yr-1, corresponding to a net emission intensity 0.16 Gg CO2-eq km-2 yr-1, and estimated per capita net emissions of 5.6 Mg CO2-eq yr-1. Our landscape approach opens opportunities to examine the sensitivities of important GHG fluxes to changes in land use and climate, management actions, and mitigation of anthropogenic emissions.
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Affiliation(s)
- Maria Holmberg
- Finnish Environment Institute (SYKE), Latokartanonkaari 11, 00790 Helsinki, Finland.
| | - Anu Akujärvi
- Finnish Environment Institute (SYKE), Latokartanonkaari 11, 00790 Helsinki, Finland
| | - Saku Anttila
- Finnish Environment Institute (SYKE), Latokartanonkaari 11, 00790 Helsinki, Finland
| | - Iida Autio
- Finnish Environment Institute (SYKE), Latokartanonkaari 11, 00790 Helsinki, Finland
| | - Markus Haakana
- National Resources Institute (Luke), Latokartanonkaari 9, FI-00790 Helsinki, Finland
| | - Virpi Junttila
- Finnish Environment Institute (SYKE), Latokartanonkaari 11, 00790 Helsinki, Finland
| | - Niko Karvosenoja
- Finnish Environment Institute (SYKE), Latokartanonkaari 11, 00790 Helsinki, Finland
| | - Pirkko Kortelainen
- Finnish Environment Institute (SYKE), Latokartanonkaari 11, 00790 Helsinki, Finland
| | - Annikki Mäkelä
- Department of Forest Sciences, P.O. Box 27, 00014 University of Helsinki, Finland
| | - Kari Minkkinen
- Department of Forest Sciences, P.O. Box 27, 00014 University of Helsinki, Finland
| | - Francesco Minunno
- Department of Forest Sciences, P.O. Box 27, 00014 University of Helsinki, Finland
| | - Katri Rankinen
- Finnish Environment Institute (SYKE), Latokartanonkaari 11, 00790 Helsinki, Finland
| | - Paavo Ojanen
- Department of Forest Sciences, P.O. Box 27, 00014 University of Helsinki, Finland
| | - Ville-Veikko Paunu
- Finnish Environment Institute (SYKE), Latokartanonkaari 11, 00790 Helsinki, Finland
| | - Mikko Peltoniemi
- National Resources Institute (Luke), Latokartanonkaari 9, FI-00790 Helsinki, Finland
| | - Terhi Rasilo
- Department of Forest Sciences, P.O. Box 27, 00014 University of Helsinki, Finland
| | - Tapani Sallantaus
- Finnish Environment Institute (SYKE), Latokartanonkaari 11, 00790 Helsinki, Finland
| | - Mikko Savolahti
- Finnish Environment Institute (SYKE), Latokartanonkaari 11, 00790 Helsinki, Finland
| | - Sakari Tuominen
- National Resources Institute (Luke), Latokartanonkaari 9, FI-00790 Helsinki, Finland
| | - Seppo Tuominen
- Finnish Environment Institute (SYKE), Latokartanonkaari 11, 00790 Helsinki, Finland
| | - Pekka Vanhala
- Finnish Environment Institute (SYKE), Latokartanonkaari 11, 00790 Helsinki, Finland
| | - Martin Forsius
- Finnish Environment Institute (SYKE), Latokartanonkaari 11, 00790 Helsinki, Finland
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Disproportionate CH 4 Sink Strength from an Endemic, Sub-Alpine Australian Soil Microbial Community. Microorganisms 2021; 9:microorganisms9030606. [PMID: 33804229 PMCID: PMC8002156 DOI: 10.3390/microorganisms9030606] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Revised: 02/27/2021] [Accepted: 03/09/2021] [Indexed: 11/17/2022] Open
Abstract
Soil-to-atmosphere methane (CH4) fluxes are dependent on opposing microbial processes of production and consumption. Here we use a soil–vegetation gradient in an Australian sub-alpine ecosystem to examine links between composition of soil microbial communities, and the fluxes of greenhouse gases they regulate. For each soil/vegetation type (forest, grassland, and bog), we measured carbon dioxide (CO2) and CH4 fluxes and their production/consumption at 5 cm intervals to a depth of 30 cm. All soils were sources of CO2, ranging from 49 to 93 mg CO2 m−2 h−1. Forest soils were strong net sinks for CH4, at rates of up to −413 µg CH4 m−2 h−1. Grassland soils varied, with some soils acting as sources and some as sinks, but overall averaged −97 µg CH4 m−2 h−1. Bog soils were net sources of CH4 (+340 µg CH4 m−2 h−1). Methanotrophs were dominated by USCα in forest and grassland soils, and Candidatus Methylomirabilis in the bog soils. Methylocystis were also detected at relatively low abundance in all soils. Our study suggests that there is a disproportionately large contribution of these ecosystems to the global soil CH4 sink, which highlights our dependence on soil ecosystem services in remote locations driven by unique populations of soil microbes. It is paramount to explore and understand these remote, hard-to-reach ecosystems to better understand biogeochemical cycles that underpin global sustainability.
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