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Wu L, Shen X, Zhang J, Liu Y, Ding C, Ma R, Lu X, Jiang M. Spatial and temporal variation of net primary productivity of herbaceous marshes and its climatic drivers in China. FRONTIERS IN PLANT SCIENCE 2024; 15:1380081. [PMID: 38807779 PMCID: PMC11130473 DOI: 10.3389/fpls.2024.1380081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/01/2024] [Accepted: 04/26/2024] [Indexed: 05/30/2024]
Abstract
Herbaceous marshes are widely distributed in China and are vital to regional ecological security and sustainable development. Vegetation net primary productivity (NPP) is a vital indicator of vegetation growth. Climatic change can significantly affect NPP, but variations in NPP of herbaceous marsh and their responses to climate change in China remain unclear. Using meteorological data and MODIS NPP data during 2000-2020, this study analyzed the spatial and temporal variations of NPP and their responses to climate change in Chinese herbaceous marshes. We found that the annual NPP of herbaceous marshes in China increased significantly at a rate of 3.34 g C/m2/a from 2000 to 2020, with an average value of 336.60 g C/m2. The increased annual total precipitation enhanced the national average NPP, whereas annual mean temperature had no significant effect on the national average NPP. Regionally, precipitation had a significant positive effect on the NPP in temperate semi-arid and arid and temperate semi-humid and humid marsh regions. For the first time, we discovered asymmetry effects of daytime and nighttime temperatures on NPP in herbaceous marshes of China. In temperate humid and semi-humid marsh regions, increased summer daytime temperature decreased the NPP while increased summer nighttime temperature increased the NPP. In the Tibetan Plateau, increased autumn daytime temperature, as well as summer daytime and nighttime temperatures could increase the NPP of herbaceous marshes. This study highlights the different influences of seasonal climate change on the NPP of herbaceous marshes in China and indicates that the differential effects of daytime and nighttime temperatures should be considering in simulating the NPP of herbaceous marshes in terrestrial ecosystem models, especially under the background of global asymmetric diurnal warming.
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Affiliation(s)
- Liyuan Wu
- Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Xiangjin Shen
- Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun, China
| | - Jiaqi Zhang
- Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Yiwen Liu
- Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Chen Ding
- Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Rong Ma
- College of Forestry, Northeast Forestry University, Harbin, China
| | - Xianguo Lu
- Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun, China
| | - Ming Jiang
- Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun, China
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Wang T, Deng Z, Zhang C, Zou Y, Xie Y, Li F, Xiao F, Peng C. Vegetation types and flood water level are dominant factors controlling the carbon sequestration potential in Dongting Lake floodplain, China. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 921:171146. [PMID: 38401724 DOI: 10.1016/j.scitotenv.2024.171146] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Revised: 02/18/2024] [Accepted: 02/19/2024] [Indexed: 02/26/2024]
Abstract
Wetlands are important carbon sinks. However, the carbon sequestration potential of flooded wetlands may be weakened owing to water regime changes induced by anthropogenic disturbances. Using the eddy covariance technique, this study quantified the effects of the water level and vegetation types on the net ecosystem CO2 exchange (NEE), gross primary production (GPP), and ecosystem respiration (Reco) from a reed marsh (Miscanthus sacchariflorus) and a sedge meadow (Carex spp.) in the Dongting Lake floodplain from 2014 to 2016. Our results indicated that the sedge meadow (-89.49 to -186.47 g C m-2 y-1) and reed marsh (-246.12 to -513.94 g C m-2 y-1) were carbon sinks on the interannual timescale. However, the sedge meadow changed from a carbon sink to a carbon source during the flooding season. The effect of flooding on the carbon sink function in the reed marsh was dependent on the water level. The carbon sink function of the reed marsh was enhanced by moderate flooding (water level under 30.5 m in Chenglingji) owing to the inhibition of Reco, but was weakened by extremely high-water levels (over 33 m in Chenglingji) during the flooding season. Seasonal variations in NEE, GPP, and Reco were closely related to photosynthetic photon flux density, soil water content, water level, soil temperature, and air temperature. We can conclude that the increase in reed area combined with the decrease in flooding days in the sedge meadow can potentially enhance the carbon sink function of the Dongting Lake floodplain.
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Affiliation(s)
- Tao Wang
- Key Laboratory of Agro-Ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha 410125, Hunan, China; Dongting Lake Station for Wetland Ecosystem Research, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha 410125, Hunan, China; University of Chinese Academy of Sciences, 100049 Beijing, China
| | - Zhengmiao Deng
- Key Laboratory of Agro-Ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha 410125, Hunan, China; Hunan Key Laboratory of Remote Sensing Monitoring of Ecological Environment in Dongting Lake Area, Hunan Natural Resources Affairs Center, Changsha 410004, China; Dongting Lake Station for Wetland Ecosystem Research, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha 410125, Hunan, China.
| | - Chengyi Zhang
- National Climate Center, China Meteorological Administration, Beijing 100081, China
| | - Yeai Zou
- Key Laboratory of Agro-Ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha 410125, Hunan, China; Dongting Lake Station for Wetland Ecosystem Research, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha 410125, Hunan, China
| | - Yonghong Xie
- Key Laboratory of Agro-Ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha 410125, Hunan, China; Dongting Lake Station for Wetland Ecosystem Research, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha 410125, Hunan, China.
| | - Feng Li
- Key Laboratory of Agro-Ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha 410125, Hunan, China; Dongting Lake Station for Wetland Ecosystem Research, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha 410125, Hunan, China
| | - Fengjin Xiao
- National Climate Center, China Meteorological Administration, Beijing 100081, China
| | - Changhui Peng
- School of Geographic Sciences, Hunan Normal University, Changsha 410081, China; Department of Biology Sciences, University of Quebec at Montreal, C.P. 8888, Succ. Centre-Ville, Montreal H3C 3P8, Canada
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Lin X, Lin S, Peng L, Chen M, Cheng X, Xie S, Bao R, Su Y, Mehmood T. Effects of polypropylene microplastics on carbon dioxide dynamics in intertidal mangrove sediments. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2024; 346:123682. [PMID: 38428788 DOI: 10.1016/j.envpol.2024.123682] [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: 11/03/2023] [Revised: 01/23/2024] [Accepted: 02/27/2024] [Indexed: 03/03/2024]
Abstract
Microplastics (MPs) in soil can influence CO2 dynamics by altering organic carbon (OC) and microbial composition. Nevertheless, the fluctuation of CO2 response attributed to MPs in mangrove sediments is unclear. This study explores the impact of micro-sized polypropylene (mPP) particles on the carbon dynamics of intertidal mangrove sediments. In the high-tide level sediment, after 28 days, the cumulative CO2 levels for varying mPP dosages were as follows: 496.86 ± 2.07, 430.38 ± 3.84 and 447.09 ± 1.72 mg kg-1 for 0.1%, 1% and 10% (w/w) mPP, respectively. The CO2 emissions were found to be increased with a 0.1% (w/w) mPP level and decreased with 1% and 10% (w/w) mPP at high-tide level sediment, suggesting a tide level-specific dose dependence of the CO2 emission pattern in mangrove sediments. Overall, results indicated that the presence of mPP in mangrove sediments would potentially affect intertidal total CO2 storage under given experimental conditions.
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Affiliation(s)
- Xubing Lin
- Key Laboratory of Agro-Forestry Environmental Processes and Ecological Regulation of Hainan Province, Center for Eco-Environment Restoration Engineering of Hainan Province, Hainan University, Haikou, 570228, China; School of Ecology and Environment, Hainan University, Haikou, Hainan Province, 570228, China
| | - Shuying Lin
- Key Laboratory of Agro-Forestry Environmental Processes and Ecological Regulation of Hainan Province, Center for Eco-Environment Restoration Engineering of Hainan Province, Hainan University, Haikou, 570228, China; School of Ecology and Environment, Hainan University, Haikou, Hainan Province, 570228, China
| | - Licheng Peng
- Key Laboratory of Agro-Forestry Environmental Processes and Ecological Regulation of Hainan Province, Center for Eco-Environment Restoration Engineering of Hainan Province, Hainan University, Haikou, 570228, China; School of Ecology and Environment, Hainan University, Haikou, Hainan Province, 570228, China.
| | - Miao Chen
- Hainan Key Laboratory of Tropical Eco-Circular Agriculture, Environment and Plant Protection Institute, Chinese Academy of Tropical Agricultural Sciences, Haikou, 571101, China
| | - Xing Cheng
- Key Laboratory of Agro-Forestry Environmental Processes and Ecological Regulation of Hainan Province, Center for Eco-Environment Restoration Engineering of Hainan Province, Hainan University, Haikou, 570228, China; School of Ecology and Environment, Hainan University, Haikou, Hainan Province, 570228, China
| | - Shiyu Xie
- Key Laboratory of Agro-Forestry Environmental Processes and Ecological Regulation of Hainan Province, Center for Eco-Environment Restoration Engineering of Hainan Province, Hainan University, Haikou, 570228, China; School of Ecology and Environment, Hainan University, Haikou, Hainan Province, 570228, China
| | - Ruiqi Bao
- Key Laboratory of Agro-Forestry Environmental Processes and Ecological Regulation of Hainan Province, Center for Eco-Environment Restoration Engineering of Hainan Province, Hainan University, Haikou, 570228, China; School of Ecology and Environment, Hainan University, Haikou, Hainan Province, 570228, China
| | - Yuanyuan Su
- Key Laboratory of Agro-Forestry Environmental Processes and Ecological Regulation of Hainan Province, Center for Eco-Environment Restoration Engineering of Hainan Province, Hainan University, Haikou, 570228, China; School of Ecology and Environment, Hainan University, Haikou, Hainan Province, 570228, China
| | - Tariq Mehmood
- Key Laboratory of Agro-Forestry Environmental Processes and Ecological Regulation of Hainan Province, Center for Eco-Environment Restoration Engineering of Hainan Province, Hainan University, Haikou, 570228, China; School of Ecology and Environment, Hainan University, Haikou, Hainan Province, 570228, China
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Wei S, Chu X, Sun B, Yuan W, Song W, Zhao M, Wang X, Li P, Han G. Climate warming negatively affects plant water-use efficiency in a seasonal hydroperiod wetland. WATER RESEARCH 2023; 242:120246. [PMID: 37348421 DOI: 10.1016/j.watres.2023.120246] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Revised: 06/12/2023] [Accepted: 06/16/2023] [Indexed: 06/24/2023]
Abstract
Climate warming has substantial influences on plant water-use efficiency (PWUE), which is defined as the ratio of plant CO2 uptake to water loss and is central to the cycles of carbon and water in ecosystems. However, it remains uncertain how does climate warming affect PWUE in wetland ecosystems, especially those with seasonally alternating water availability during the growing season. In this study, we used a continuous 10-year (2011-2020) eddy covariance (EC) dataset from a seasonal hydroperiod wetland coupled with a 15-year (2003-2017) satellite-based dataset (called PML-V2) and an in situ warming experiment to examine the climate warming impacts on wetland PWUE. The 10-year EC observational results revealed that rising temperatures had significant negative impacts on the interannual variations in wetland PWUE, and increased transpiration (Et) rather than changes in gross primary productivity (GPP) dominated these negative impacts. Furthermore, the 15-year satellite-based evidence confirmed that, in the study region, climate warming had significant negative consequences for the interannual variations in wetland PWUE by enhancing wetland Et. Lastly, at the leaf-scale, the light response curves of leaf photosynthesis, leaf Et, and leaf-scale PWUE indicated that wetland plants need to consume more water during the photosynthesis process under warmer conditions. These findings provide a fresh perspective on how climate warming influences carbon and water cycles in wetland ecosystems.
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Affiliation(s)
- Siyu Wei
- Key Laboratory of Coastal Zone Environmental Processes and Ecological Remediation, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, Shandong, China; Yellow River Delta Field Observation and Research Station of Coastal Wetland Ecosystem, Chinese Academy of Sciences, Dongying, Shandong, China; University of Chinese Academy of Sciences, Beijing, China
| | - Xiaojing Chu
- Key Laboratory of Coastal Zone Environmental Processes and Ecological Remediation, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, Shandong, China; Yellow River Delta Field Observation and Research Station of Coastal Wetland Ecosystem, Chinese Academy of Sciences, Dongying, Shandong, China
| | - Baoyu Sun
- Yellow River Delta Field Observation and Research Station of Coastal Wetland Ecosystem, Chinese Academy of Sciences, Dongying, Shandong, China; Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, School of Life Sciences, Fudan University, Shanghai, China
| | - Wenping Yuan
- School of Atmospheric Sciences, Guangdong Province Key Laboratory for Climate Change and Natural Disaster Studies, Zhuhai Key Laboratory of Dynamics Urban Climate and Ecology, Sun Yat-sen University, Zhuhai, Guangdong, China; Southern Marine Science and Engineering Guangdong Laboratory, Zhuhai, Guangdong, China
| | - Weimin Song
- Key Laboratory of Coastal Zone Environmental Processes and Ecological Remediation, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, Shandong, China; Yellow River Delta Field Observation and Research Station of Coastal Wetland Ecosystem, Chinese Academy of Sciences, Dongying, Shandong, China
| | - Mingliang Zhao
- Key Laboratory of Coastal Zone Environmental Processes and Ecological Remediation, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, Shandong, China; Yellow River Delta Field Observation and Research Station of Coastal Wetland Ecosystem, Chinese Academy of Sciences, Dongying, Shandong, China
| | - Xiaojie Wang
- Key Laboratory of Coastal Zone Environmental Processes and Ecological Remediation, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, Shandong, China; Yellow River Delta Field Observation and Research Station of Coastal Wetland Ecosystem, Chinese Academy of Sciences, Dongying, Shandong, China
| | - Peiguang Li
- Key Laboratory of Coastal Zone Environmental Processes and Ecological Remediation, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, Shandong, China; Yellow River Delta Field Observation and Research Station of Coastal Wetland Ecosystem, Chinese Academy of Sciences, Dongying, Shandong, China
| | - Guangxuan Han
- Key Laboratory of Coastal Zone Environmental Processes and Ecological Remediation, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, Shandong, China; Yellow River Delta Field Observation and Research Station of Coastal Wetland Ecosystem, Chinese Academy of Sciences, Dongying, Shandong, China; University of Chinese Academy of Sciences, Beijing, China.
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Yao X, Song C. Effect of different factors dominated by water level environment on wetland carbon emissions. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2022; 29:74150-74162. [PMID: 35633453 DOI: 10.1007/s11356-022-20289-9] [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: 01/05/2022] [Accepted: 04/12/2022] [Indexed: 06/15/2023]
Abstract
The exacerbation of global warming has led to changes in wetland carbon emissions worldwide. Therefore, we conducted a meta-analysis of methane (CH4) and carbon dioxide (CO2) emissions in wetland ecosystem and explored the underlying mechanisms. Our finding indicated that (1) water level of -50 to 30 cm (the negative value represents the depth of the groundwater table, whereas the positive value represents the height of the above-ground water table) and -10 cm will result in a large CH4 and CO2 emissions, respectively; (2) CO2 and CH4 massive emissions occurred at the temperature range of 15-20 °C and > 20 °C, respectively; (3) CH4 and CO2 emissions were higher when the mean annual precipitation (MAP) was between 400 and 800 mm, but lower at an range of 800-1200 mm; (4) there was no significant difference in CH4 and CO2 emissions in marsh over time; however, CO2 emissions in fen were relatively high; (5) there was no significant difference in CO2 emissions between the forest, grass, and shrub groups; there was also no significant difference in CH4 emission within the forest group; and (6) MAP has a low impact (0.577) on the CO2 emissions of wetlands. Collectively, our findings highlight the characteristics of wetland CH4 and CO2 emissions under different conditions dominated by water level, enhance our understanding of the potential mechanisms that govern these effects, and provide basis for future wetland management and restoration in the future.
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Affiliation(s)
- Xiaochen Yao
- 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.
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Yu Z, Staudhammer CL, Malone SL, Oberbauer SF, Zhao J, Cherry JA, Starr G. Biophysical Factors Influence Methane Fluxes in Subtropical Freshwater Wetlands Using Eddy Covariance Methods. Ecosystems 2022. [DOI: 10.1007/s10021-022-00787-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Zheng Y, Liu H, Du Q, Liu Y, Sun J, Cun H, Järvi L. Effects of precipitation seasonal distribution on net ecosystem CO 2 exchange over an alpine meadow in the southeastern Tibetan Plateau. INTERNATIONAL JOURNAL OF BIOMETEOROLOGY 2022; 66:1561-1573. [PMID: 35522348 DOI: 10.1007/s00484-022-02300-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/01/2022] [Revised: 04/25/2022] [Accepted: 04/28/2022] [Indexed: 06/14/2023]
Abstract
Ecosystem carbon balance might be affected by the variability of seasonal distribution of precipitation under global climate change. Using the eddy covariance (EC) technique, long-term observations of ecosystem net CO2 exchange (NEE) were acquired over Lijiang alpine meadow in the southeastern Tibetan Plateau from January 2014 to August 2019. During the wet season (from June to October), Lijiang meadow functioned as a carbon sink (- 37.6 ± 22.5 g C m-2 month-1), while in dry season, the meadow varied between a weak carbon source and sink with an average monthly NEE of - 3.9 ± 11.9 g C m-2 month-1. Monthly CO2 fluxes were mainly controlled by air temperature and soil water content. A large annual variation of CO2 uptake was observed. The annual NEE was - 140.3 g C m-2 year-1 in 2014 while - 247.0 g C m-2 year-1 in 2016. Correspondingly, the precipitation in wet season accounted 90% of annual precipitation in 2014 and 74% of that in 2016 despite the annual precipitation was larger than 1200 mm in both years. More precipitation in dry season can lead to longer period of net CO2 uptake, while more precipitation concentrated in wet season depressed the meadow's light response through the decrease of the magnitude of light-saturated net CO2 exchange (NEEsat) at the onset and the end of growing season.
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Affiliation(s)
- Yingqi Zheng
- State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, 100029, China
- University of Chinese Academy of Sciences, Beijing, 100029, China
| | - Huizhi Liu
- State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, 100029, China.
- University of Chinese Academy of Sciences, Beijing, 100029, China.
| | - Qun Du
- State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, 100029, China
- University of Chinese Academy of Sciences, Beijing, 100029, China
| | - Yang Liu
- State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, 100029, China
| | - Jihua Sun
- Yunnan Meteorological Observatory, Kunming, 530100, China
| | - Huancai Cun
- Lijiang Meteorological Bureau, Lijiang, 674199, China
| | - Leena Järvi
- Institute for Atmospheric and Earth System Research/Physics, Faculty of Science, University of Helsinki, 00560, Helsinki, Finland
- Faculty of Science, Helsinki Institute of Sustainability Science, University of Helsinki, 00560, Helsinki, Finland
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Kominoski JS, Pachón J, Brock JT, McVoy C, Malone SL. Understanding drivers of aquatic ecosystem metabolism in freshwater subtropical ridge and slough wetlands. Ecosphere 2021. [DOI: 10.1002/ecs2.3849] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Affiliation(s)
- John S. Kominoski
- Department of Biological Sciences Institute of Environment Florida International University Miami Florida 33199 USA
| | - Julio Pachón
- Department of Biological Sciences Institute of Environment Florida International University Miami Florida 33199 USA
| | | | | | - Sparkle L. Malone
- Department of Biological Sciences Institute of Environment Florida International University Miami Florida 33199 USA
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Cui H, Bai J, Du S, Wang J, Keculah GN, Wang W, Zhang G, Jia J. Interactive effects of groundwater level and salinity on soil respiration in coastal wetlands of a Chinese delta. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2021; 286:117400. [PMID: 34058447 DOI: 10.1016/j.envpol.2021.117400] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Revised: 05/03/2021] [Accepted: 05/13/2021] [Indexed: 06/12/2023]
Abstract
Coastal wetland soils serve as a great C sink or source, which highly depends on soil carbon flux affected by complex hydrology in relation to salinity. We conducted a field experiment to investigate soil respiration of three coastal wetlands with different land covers (BL: bare land; SS: Suaeda salsa; PL: Phragmites australis) from May to October in 2012 and 2013 under three groundwater tables (deeper, medium, and shallower water tables) in the Yellow River Delta of China, and to characterize the spatial and temporal changes and the primary environmental drivers of soil respiration in coastal wetlands. Our results showed that the elevated groundwater table decreased soil CO2 emissions, and the soil respiration rates at each groundwater table exhibited seasonal and diurnal dynamics, where significant differences were observed among coastal wetlands with different groundwater tables (p < 0.05), with the average CO2 emission of 146.52 ± 13.66 μmol m-2s-1 for deeper water table wetlands, 105.09 ± 13.48 μmol m-2s-1 for medium water table wetlands and 54.32 ± 10.02 μmol m-2s-1 for shallower water table wetlands. Compared with bare land and Suaeda salsa wetlands, higher soil respiration was observed in Phragmites australis wetlands. Generally, soil respiration was greatly affected by salinity and soil water content. There were significant correlations between groundwater tables, electrical conductivity and soil respiration (p < 0.05), indicating that soil respiration in coastal wetlands was limited by electrical conductivity and groundwater tables and soil C sink might be improved by regulating water and salt conditions. We have also observed that soil respiration and temperature showed an exponential relationship on a seasonal scale. Taking into consideration the changes in groundwater tables and salinity that might be caused by sea level rise in the context of global warming, we emphasize the importance of groundwater level and salinity in the carbon cycle process of estuarine wetlands in the future.
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Affiliation(s)
- Hao Cui
- State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing, 100875, China
| | - Junhong Bai
- State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing, 100875, China.
| | - Shudong Du
- State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing, 100875, China
| | - Junjing Wang
- State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing, 100875, China
| | - Ghemelee Nitta Keculah
- State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing, 100875, China
| | - Wei Wang
- State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing, 100875, China
| | - Guangliang Zhang
- State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing, 100875, China
| | - Jia Jia
- State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing, 100875, China
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Integrating Aquatic Metabolism and Net Ecosystem CO2 Balance in Short- and Long-Hydroperiod Subtropical Freshwater Wetlands. Ecosystems 2021. [DOI: 10.1007/s10021-021-00672-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
AbstractHow aquatic primary productivity influences the carbon (C) sequestering capacity of wetlands is uncertain. We evaluated the magnitude and variability in aquatic C dynamics and compared them to net ecosystem CO2 exchange (NEE) and ecosystem respiration (Reco) rates within calcareous freshwater wetlands in Everglades National Park. We continuously recorded 30-min measurements of dissolved oxygen (DO), water level, water temperature (Twater), and photosynthetically active radiation (PAR). These measurements were coupled with ecosystem CO2 fluxes over 5 years (2012–2016) in a long-hydroperiod peat-rich, freshwater marsh and a short-hydroperiod, freshwater marl prairie. Daily net aquatic primary productivity (NAPP) rates indicated both wetlands were generally net heterotrophic. Gross aquatic primary productivity (GAPP) ranged from 0 to − 6.3 g C m−2 day−1 and aquatic respiration (RAq) from 0 to 6.13 g C m−2 day−1. Nonlinear interactions between water level, Twater, and GAPP and RAq resulted in high variability in NAPP that contributed to NEE. Net aquatic primary productivity accounted for 4–5% of the deviance explained in NEE rates. With respect to the flux magnitude, daily NAPP was a greater proportion of daily NEE at the long-hydroperiod site (mean = 95%) compared to the short-hydroperiod site (mean = 64%). Although we have confirmed the significant contribution of NAPP to NEE in both long- and short-hydroperiod freshwater wetlands, the decoupling of the aquatic and ecosystem fluxes could largely depend on emergent vegetation, the carbonate cycle, and the lateral C flux.
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Sun B, Yan L, Jiang M, Li X, Han G, Xia J. Reduced magnitude and shifted seasonality of CO 2 sink by experimental warming in a coastal wetland. Ecology 2020; 102:e03236. [PMID: 33098567 DOI: 10.1002/ecy.3236] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/11/2020] [Revised: 08/21/2020] [Accepted: 09/14/2020] [Indexed: 01/01/2023]
Abstract
Coastal wetlands have the highest carbon sequestration rate per unit area among all unmanaged natural ecosystems. However, how the magnitude and seasonality of the CO2 sink in coastal wetlands will respond to future climate warming remains unclear. Here, based on measurements of ecosystem CO2 fluxes in a field experiment in the Yellow River Delta, we found that experimental warming (i.e., a 2.4°C increase in soil temperature) reduced net ecosystem productivity (NEP) by 23.7% across two growing seasons of 2017-2018. Such a reduction in NEP resulted from the greater decrease in gross primary productivity (GPP) than ecosystem respiration (ER) under warming. The negative warming effect on NEP mainly occurred in summer (-43.9%) but not in autumn (+61.3%), leading to a shifted NEP seasonality under warming. Further analyses showed that the warming effects on ecosystem CO2 exchange were mainly controlled by soil salinity and its corresponding impacts on species composition. For example, warming increased soil salinity (+35.0%), reduced total aboveground biomass (-9.9%), and benefited the growth of plant species with high salt tolerance and late peak growth. To the best of our knowledge, this study provides the first experimental evidence on the reduced magnitude and shifted seasonality of CO2 exchange under climate warming in coastal wetlands. These findings underscore the high vulnerability of wetland CO2 sink in coastal regions under future climate change.
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Affiliation(s)
- Baoyu Sun
- State Key Laboratory of Estuarine and Coastal Research, Shanghai Key Lab for Urban Ecological Processes and Eco-Restoration, School of Ecological and Environmental Sciences, East China Normal University, Shanghai, 200000, China.,Joint Translational Science and Technology Research Institute, East China Normal University and Haifa University, Shanghai, 200000, China.,Key Laboratory of Coastal Zone Environmental Processes and Ecological Remediation, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, 264000, China
| | - Liming Yan
- State Key Laboratory of Estuarine and Coastal Research, Shanghai Key Lab for Urban Ecological Processes and Eco-Restoration, School of Ecological and Environmental Sciences, East China Normal University, Shanghai, 200000, China.,Research Center for Global Change and Ecological Forecasting, East China Normal University, Shanghai, 200000, China
| | - Ming Jiang
- State Key Laboratory of Estuarine and Coastal Research, Shanghai Key Lab for Urban Ecological Processes and Eco-Restoration, School of Ecological and Environmental Sciences, East China Normal University, Shanghai, 200000, China.,Research Center for Global Change and Ecological Forecasting, East China Normal University, Shanghai, 200000, China
| | - Xinge Li
- Key Laboratory of Coastal Zone Environmental Processes and Ecological Remediation, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, 264000, China.,University of Chinese Academy of Sciences, Beijing, 100000, China
| | - Guangxuan Han
- Key Laboratory of Coastal Zone Environmental Processes and Ecological Remediation, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, 264000, China.,University of Chinese Academy of Sciences, Beijing, 100000, China
| | - Jianyang Xia
- State Key Laboratory of Estuarine and Coastal Research, Shanghai Key Lab for Urban Ecological Processes and Eco-Restoration, School of Ecological and Environmental Sciences, East China Normal University, Shanghai, 200000, China.,Research Center for Global Change and Ecological Forecasting, East China Normal University, Shanghai, 200000, China
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12
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Wang F, Kroeger KD, Gonneea ME, Pohlman JW, Tang J. Water salinity and inundation control soil carbon decomposition during salt marsh restoration: An incubation experiment. Ecol Evol 2019; 9:1911-1921. [PMID: 30847081 PMCID: PMC6392403 DOI: 10.1002/ece3.4884] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Revised: 10/04/2018] [Accepted: 10/09/2018] [Indexed: 11/07/2022] Open
Abstract
Coastal wetlands are a significant carbon (C) sink since they store carbon in anoxic soils. This ecosystem service is impacted by hydrologic alteration and management of these coastal habitats. Efforts to restore tidal flow to former salt marshes have increased in recent decades and are generally associated with alteration of water inundation levels and salinity. This study examined the effect of water level and salinity changes on soil organic matter decomposition during a 60-day incubation period. Intact soil cores from impounded fresh water marsh and salt marsh were incubated after addition of either sea water or fresh water under flooded and drained water levels. Elevating fresh water marsh salinity to 6 to 9 ppt enhanced CO2 emission by 50%-80% and most typically decreased CH4 emissions, whereas, decreasing the salinity from 26 ppt to 19 ppt in salt marsh soils had no effect on CO2 or CH4 fluxes. The effect from altering water levels was more pronounced with drained soil cores emitting ~10-fold more CO2 than the flooded treatment in both marsh sediments. Draining soil cores also increased dissolved organic carbon (DOC) concentrations. Stable carbon isotope analysis of CO2 generated during the incubations of fresh water marsh cores in drained soils demonstrates that relict peat OC that accumulated when the marsh was saline was preferentially oxidized when sea water was introduced. This study suggests that restoration of tidal flow that raises the water level from drained conditions would decrease aerobic decomposition and enhance C sequestration. It is also possible that the restoration would increase soil C decomposition of deeper deposits by anaerobic oxidation, however this impact would be minimal compared to lower emissions expected due to the return of flooding conditions.
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Affiliation(s)
- Faming Wang
- Marine Biological LaboratoryThe Ecosystems CenterWoods HoleMassachusetts
- USGS Woods Hole Coastal & Marine Science CenterWoods HoleMassachusetts
- Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical GardenChinese Academy of SciencesGuangzhouChina
| | - Kevin D. Kroeger
- USGS Woods Hole Coastal & Marine Science CenterWoods HoleMassachusetts
| | - Meagan E. Gonneea
- USGS Woods Hole Coastal & Marine Science CenterWoods HoleMassachusetts
| | - John W. Pohlman
- USGS Woods Hole Coastal & Marine Science CenterWoods HoleMassachusetts
| | - Jianwu Tang
- Marine Biological LaboratoryThe Ecosystems CenterWoods HoleMassachusetts
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13
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Wilson BJ, Servais S, Mazzei V, Kominoski JS, Hu M, Davis SE, Gaiser E, Sklar F, Bauman L, Kelly S, Madden C, Richards J, Rudnick D, Stachelek J, Troxler TG. Salinity pulses interact with seasonal dry-down to increase ecosystem carbon loss in marshes of the Florida Everglades. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2018; 28:2092-2108. [PMID: 30376192 DOI: 10.1002/eap.1798] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2018] [Revised: 07/10/2018] [Accepted: 08/02/2018] [Indexed: 06/08/2023]
Abstract
Coastal wetlands are globally important sinks of organic carbon (C). However, to what extent wetland C cycling will be affected by accelerated sea-level rise (SLR) and saltwater intrusion is unknown, especially in coastal peat marshes where water flow is highly managed. Our objective was to determine how the ecosystem C balance in coastal peat marshes is influenced by elevated salinity. For two years, we made monthly in situ manipulations of elevated salinity in freshwater (FW) and brackish water (BW) sites within Everglades National Park, Florida, USA. Salinity pulses interacted with marsh-specific variability in seasonal hydroperiods whereby effects of elevated pulsed salinity on gross ecosystem productivity (GEP), ecosystem respiration (ER), and net ecosystem productivity (NEP) were dependent on marsh inundation level. We found little effect of elevated salinity on C cycling when both marsh sites were inundated, but when water levels receded below the soil surface, the BW marsh shifted from a C sink to a C source. During these exposed periods, we observed an approximately threefold increase in CO2 efflux from the marsh as a result of elevated salinity. Initially, elevated salinity pulses did not affect Cladium jamaicense biomass, but aboveground biomass began to be significantly decreased in the saltwater amended plots after two years of exposure at the BW site. We found a 65% (FW) and 72% (BW) reduction in live root biomass in the soil after two years of exposure to elevated salinity pulses. Regardless of salinity treatment, the FW site was C neutral while the BW site was a strong C source (-334 to -454 g C·m-2 ·yr-1 ), particularly during dry-down events. A loss of live roots coupled with annual net CO2 losses as marshes transition from FW to BW likely contributes to the collapse of peat soils observed in the coastal Everglades. As SLR increases the rate of saltwater intrusion into coastal wetlands globally, understanding how water management influences C gains and losses from these systems is crucial. Under current Everglades' water management, drought lengthens marsh dry-down periods, which, coupled with saltwater intrusion, accelerates CO2 loss from the marsh.
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Affiliation(s)
- Benjamin J Wilson
- Department of Biological Sciences and Southeast Environmental Research Center, Florida International University, Miami, Florida, 33199, USA
| | - Shelby Servais
- Department of Biological Sciences and Southeast Environmental Research Center, Florida International University, Miami, Florida, 33199, USA
| | - Viviana Mazzei
- Department of Biological Sciences and Southeast Environmental Research Center, Florida International University, Miami, Florida, 33199, USA
| | - John S Kominoski
- Department of Biological Sciences and Southeast Environmental Research Center, Florida International University, Miami, Florida, 33199, USA
| | - Minjie Hu
- College of the Environment and Ecology, Xiamen University, Xiamen, 361102, China
| | | | - Evelyn Gaiser
- Department of Biological Sciences and Southeast Environmental Research Center, Florida International University, Miami, Florida, 33199, USA
| | - Fred Sklar
- South Florida Water Management District, West Palm Beach, Florida, 33406, USA
| | - Laura Bauman
- Department of Biological Sciences and Southeast Environmental Research Center, Florida International University, Miami, Florida, 33199, USA
| | - Stephen Kelly
- South Florida Water Management District, West Palm Beach, Florida, 33406, USA
| | - Christopher Madden
- South Florida Water Management District, West Palm Beach, Florida, 33406, USA
| | - Jennifer Richards
- Department of Biological Sciences and Southeast Environmental Research Center, Florida International University, Miami, Florida, 33199, USA
| | - David Rudnick
- Everglades National Park, Homestead, Florida, 33034, USA
| | - Joseph Stachelek
- South Florida Water Management District, West Palm Beach, Florida, 33406, USA
- Michigan State University, East Lansing, Michigan, 48824, USA
| | - Tiffany G Troxler
- Department of Biological Sciences and Southeast Environmental Research Center, Florida International University, Miami, Florida, 33199, USA
- Sea Level Solutions Center, Florida International University, Miami, Florida, 33199, USA
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14
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Lu W, Xiao J, Liu F, Zhang Y, Liu C, Lin G. Contrasting ecosystem CO 2 fluxes of inland and coastal wetlands: a meta-analysis of eddy covariance data. GLOBAL CHANGE BIOLOGY 2017; 23:1180-1198. [PMID: 27400026 DOI: 10.1111/gcb.13424] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Accepted: 06/26/2016] [Indexed: 06/06/2023]
Abstract
Wetlands play an important role in regulating the atmospheric carbon dioxide (CO2 ) concentrations and thus affecting the climate. However, there is still lack of quantitative evaluation of such a role across different wetland types, especially at the global scale. Here, we conducted a meta-analysis to compare ecosystem CO2 fluxes among various types of wetlands using a global database compiled from the literature. This database consists of 143 site-years of eddy covariance data from 22 inland wetland and 21 coastal wetland sites across the globe. Coastal wetlands had higher annual gross primary productivity (GPP), ecosystem respiration (Re ), and net ecosystem productivity (NEP) than inland wetlands. On a per unit area basis, coastal wetlands provided large CO2 sinks, while inland wetlands provided small CO2 sinks or were nearly CO2 neutral. The annual CO2 sink strength was 93.15 and 208.37 g C m-2 for inland and coastal wetlands, respectively. Annual CO2 fluxes were mainly regulated by mean annual temperature (MAT) and mean annual precipitation (MAP). For coastal and inland wetlands combined, MAT and MAP explained 71%, 54%, and 57% of the variations in GPP, Re , and NEP, respectively. The CO2 fluxes of wetlands were also related to leaf area index (LAI). The CO2 fluxes also varied with water table depth (WTD), although the effects of WTD were not statistically significant. NEP was jointly determined by GPP and Re for both inland and coastal wetlands. However, the NEP/Re and NEP/GPP ratios exhibited little variability for inland wetlands and decreased for coastal wetlands with increasing latitude. The contrasting of CO2 fluxes between inland and coastal wetlands globally can improve our understanding of the roles of wetlands in the global C cycle. Our results also have implications for informing wetland management and climate change policymaking, for example, the efforts being made by international organizations and enterprises to restore coastal wetlands for enhancing blue carbon sinks.
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Affiliation(s)
- Weizhi Lu
- National Marine Environmental Monitoring Center, State Oceanic Administration, Dalian, 116023, China
| | - Jingfeng Xiao
- Earth Systems Research Center, Institute for the Study of Earth, Oceans, and Space, University of New Hampshire, Durham, NH, 03824, USA
| | - Fang Liu
- Ministry of Education Key Laboratory for Earth System Modeling, Center for Earth System Science, Tsinghua University, Beijing, 100084, China
| | - Yue Zhang
- National Marine Environmental Monitoring Center, State Oceanic Administration, Dalian, 116023, China
| | - Chang'an Liu
- National Marine Environmental Monitoring Center, State Oceanic Administration, Dalian, 116023, China
| | - Guanghui Lin
- Ministry of Education Key Laboratory for Earth System Modeling, Center for Earth System Science, Tsinghua University, Beijing, 100084, China
- Division of Ocean Science and Technology, Graduate School at Shenzhen, Tsinghua University, Shenzhen, 518055, China
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15
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Lewis DB, Feit SJ. Connecting carbon and nitrogen storage in rural wetland soil to groundwater abstraction for urban water supply. GLOBAL CHANGE BIOLOGY 2015; 21:1704-1714. [PMID: 25394332 DOI: 10.1111/gcb.12782] [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: 05/08/2014] [Revised: 08/23/2014] [Accepted: 09/24/2014] [Indexed: 06/04/2023]
Abstract
We investigated whether groundwater abstraction for urban water supply diminishes the storage of carbon (C), nitrogen (N), and organic matter in the soil of rural wetlands. Wetland soil organic matter (SOM) benefits air and water quality by sequestering large masses of C and N. Yet, the accumulation of wetland SOM depends on soil inundation, so we hypothesized that groundwater abstraction would diminish stocks of SOM, C, and N in wetland soils. Predictions of this hypothesis were tested in two types of subtropical, depressional-basin wetland: forested swamps and herbaceous-vegetation marshes. In west-central Florida, >650 ML groundwater day(-1) are abstracted for use primarily in the Tampa Bay metropolis. At higher abstraction volumes, water tables were lower and wetlands had shorter hydroperiods (less time inundated). In turn, wetlands with shorter hydroperiods had 50-60% less SOM, C, and N per kg soil. In swamps, SOM loss caused soil bulk density to double, so areal soil C and N storage per m(2) through 30.5 cm depth was diminished by 25-30% in short-hydroperiod swamps. In herbaceous-vegetation marshes, short hydroperiods caused a sharper decline in N than in C. Soil organic matter, C, and N pools were not correlated with soil texture or with wetland draining-reflooding frequency. Many years of shortened hydroperiod were probably required to diminish soil organic matter, C, and N pools by the magnitudes we observed. This diminution might have occurred decades ago, but could be maintained contemporarily by the failure each year of chronically drained soils to retain new organic matter inputs. In sum, our study attributes the contraction of hydroperiod and loss of soil organic matter, C, and N from rural wetlands to groundwater abstraction performed largely for urban water supply, revealing teleconnections between rural ecosystem change and urban resource demand.
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Affiliation(s)
- David Bruce Lewis
- Department of Integrative Biology, University of South Florida, Tampa, FL, USA
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16
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Malone SL, Staudhammer CL, Oberbauer SF, Olivas P, Ryan MG, Schedlbauer JL, Loescher HW, Starr G. El Niño Southern Oscillation (ENSO) enhances CO2 exchange rates in freshwater Marsh ecosystems in the Florida everglades. PLoS One 2014; 9:e115058. [PMID: 25521299 PMCID: PMC4270789 DOI: 10.1371/journal.pone.0115058] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2014] [Accepted: 11/10/2014] [Indexed: 12/03/2022] Open
Abstract
This research examines the relationships between El Niño Southern Oscillation (ENSO), water level, precipitation patterns and carbon dioxide (CO2) exchange rates in the freshwater wetland ecosystems of the Florida Everglades. Data was obtained over a 5-year study period (2009–2013) from two freshwater marsh sites located in Everglades National Park that differ in hydrology. At the short-hydroperiod site (Taylor Slough; TS) and the long-hydroperiod site (Shark River Slough; SRS) fluctuations in precipitation patterns occurred with changes in ENSO phase, suggesting that extreme ENSO phases alter Everglades hydrology which is known to have a substantial influence on ecosystem carbon dynamics. Variations in both ENSO phase and annual net CO2 exchange rates co-occurred with changes in wet and dry season length and intensity. Combined with site-specific seasonality in CO2 exchanges rates, El Niño and La Niña phases magnified season intensity and CO2 exchange rates at both sites. At TS, net CO2 uptake rates were higher in the dry season, whereas SRS had greater rates of carbon sequestration during the wet season. As La Niña phases were concurrent with drought years and extended dry seasons, TS became a greater sink for CO2 on an annual basis (−11 to −110 g CO2 m−2 yr−1) compared to El Niño and neutral years (−5 to −43.5 g CO2 m−2 yr−1). SRS was a small source for CO2 annually (1.81 to 80 g CO2 m−2 yr−1) except in one exceptionally wet year that was associated with an El Niño phase (−16 g CO2 m−2 yr−1). Considering that future climate predictions suggest a higher frequency and intensity in El Niño and La Niña phases, these results indicate that changes in extreme ENSO phases will significantly alter CO2 dynamics in the Florida Everglades.
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Affiliation(s)
- Sparkle L Malone
- Department of Biological Sciences, University of Alabama, Tuscaloosa, AL, United States of America; Rocky Mountain Research Station, US Forest Service, Ft. Collins, CO, United States of America
| | - Christina L Staudhammer
- Department of Biological Sciences, University of Alabama, Tuscaloosa, AL, United States of America
| | - Steven F Oberbauer
- Department of Biological Sciences, Florida International University, Miami, FL, United States of America
| | - Paulo Olivas
- Department of Biological Sciences, Florida International University, Miami, FL, United States of America
| | - Michael G Ryan
- Rocky Mountain Research Station, US Forest Service, Ft. Collins, CO, United States of America; Natural Resource Ecology Laboratory, Colorado State University, Fort Collins, CO, United States of America
| | - Jessica L Schedlbauer
- Department of Biological Sciences, Florida International University, Miami, FL, United States of America; Department of Biology, West Chester University, West Chester, PA, United States of America
| | - Henry W Loescher
- National Ecological Observatory Network Inc., Boulder, CO, 80301, United States of America; Institute of Arctic and Alpine Research, University of Colorado, Boulder, CO, United States of America
| | - Gregory Starr
- Department of Biological Sciences, University of Alabama, Tuscaloosa, AL, United States of America
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17
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Malone SL, Starr G, Staudhammer CL, Ryan MG. Effects of simulated drought on the carbon balance of Everglades short-hydroperiod marsh. GLOBAL CHANGE BIOLOGY 2013; 19:2511-2523. [PMID: 23554284 DOI: 10.1111/gcb.12211] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2013] [Accepted: 03/17/2013] [Indexed: 06/02/2023]
Abstract
Hydrology drives the carbon balance of wetlands by controlling the uptake and release of CO2 and CH4 . Longer dry periods in between heavier precipitation events predicted for the Everglades region, may alter the stability of large carbon pools in this wetland's ecosystems. To determine the effects of drought on CO2 fluxes and CH4 emissions, we simulated changes in hydroperiod with three scenarios that differed in the onset rate of drought (gradual, intermediate, and rapid transition into drought) on 18 freshwater wetland monoliths collected from an Everglades short-hydroperiod marsh. Simulated drought, regardless of the onset rate, resulted in higher net CO2 losses net ecosystem exchange (NEE) over the 22-week manipulation. Drought caused extensive vegetation dieback, increased ecosystem respiration (Reco ), and reduced carbon uptake gross ecosystem exchange (GEE). Photosynthetic potential measured by reflective indices (photochemical reflectance index, water index, normalized phaeophytinization index, and the normalized difference vegetation index) indicated that water stress limited GEE and inhibited Reco . As a result of drought-induced dieback, NEE did not offset methane production during periods of inundation. The average ratio of net CH4 to NEE over the study period was 0.06, surpassing the 100-year greenhouse warming compensation point for CH4 (0.04). Drought-induced diebacks of sawgrass (C3 ) led to the establishment of the invasive species torpedograss (C4 ) when water was resupplied. These changes in the structure and function indicate that freshwater marsh ecosystems can become a net source of CO2 and CH4 to the atmosphere, even following an extended drought. Future changes in precipitation patterns and drought occurrence/duration can change the carbon storage capacity of freshwater marshes from sinks to sources of carbon to the atmosphere. Therefore, climate change will impact the carbon storage capacity of freshwater marshes by influencing water availability and the potential for positive feedbacks on radiative forcing.
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Affiliation(s)
- Sparkle L Malone
- Department of Biological Sciences, University of Alabama, Tuscaloosa, AL 35401, USA.
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18
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Whelan A, Mitchell R, Staudhammer C, Starr G. Cyclic occurrence of fire and its role in carbon dynamics along an edaphic moisture gradient in longleaf pine ecosystems. PLoS One 2013; 8:e54045. [PMID: 23335986 PMCID: PMC3545999 DOI: 10.1371/journal.pone.0054045] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2012] [Accepted: 12/06/2012] [Indexed: 11/18/2022] Open
Abstract
Fire regulates the structure and function of savanna ecosystems, yet we lack understanding of how cyclic fire affects savanna carbon dynamics. Furthermore, it is largely unknown how predicted changes in climate may impact the interaction between fire and carbon cycling in these ecosystems. This study utilizes a novel combination of prescribed fire, eddy covariance (EC) and statistical techniques to investigate carbon dynamics in frequently burned longleaf pine savannas along a gradient of soil moisture availability (mesic, intermediate and xeric). This research approach allowed us to investigate the complex interactions between carbon exchange and cyclic fire along the ecological amplitude of longleaf pine. Over three years of EC measurement of net ecosystem exchange (NEE) show that the mesic site was a net carbon sink (NEE = −2.48 tonnes C ha−1), while intermediate and xeric sites were net carbon sources (NEE = 1.57 and 1.46 tonnes C ha−1, respectively), but when carbon losses due to fuel consumption were taken into account, all three sites were carbon sources (10.78, 7.95 and 9.69 tonnes C ha−1 at the mesic, intermediate and xeric sites, respectively). Nonetheless, rates of NEE returned to pre-fire levels 1–2 months following fire. Consumption of leaf area by prescribed fire was associated with reduction in NEE post-fire, and the system quickly recovered its carbon uptake capacity 30–60 days post fire. While losses due to fire affected carbon balances on short time scales (instantaneous to a few months), drought conditions over the final two years of the study were a more important driver of net carbon loss on yearly to multi-year time scales. However, longer-term observations over greater environmental variability and additional fire cycles would help to more precisely examine interactions between fire and climate and make future predictions about carbon dynamics in these systems.
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Affiliation(s)
- Andrew Whelan
- Department of Biological Sciences, University of Alabama, Tuscaloosa, Alabama, USA
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