The Experts below are selected from a list of 15306 Experts worldwide ranked by ideXlab platform
Guangxuan Han - One of the best experts on this subject based on the ideXlab platform.
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responses of soil co2 and ch4 emissions to changing water table level in a Coastal Wetland
Journal of Cleaner Production, 2020Co-Authors: Guangxuan Han, Weimin Song, Mingliang Zhao, Franziska Eller, Jianping Wang, Changsheng JiangAbstract:Abstract Global climate change and in particular sea level rise have resulted in water table level rise in the Coastal Wetland, which may alter the magnitude and direction of carbon flux. However, the degree to which different water table level affects soil CO2 and CH4 emissions remains uncertain in Coastal Wetland. Here, a soil microcosm experiment with five water table levels (−40, −30, −20, −10, 0 cm) was conducted in the Yellow River Delta, China. The water table level was controlled by manual. The soil CO2 and CH4 emissions of each water table levels were measured during 150-days incubation in 2018. Our results showed that water table level rise decreased soil CO2 emissions, while increased soil CH4 emissions. However, there was no significant difference in soil CO2 and CH4 emissions from −20 to −40 water table levels, respectively. In addition, water table level rise significant alter soil physical and chemical properties in the uppermost soil layer (0–10 cm) in Coastal Wetland, in particular soil moisture and salinity, which probably jointly affected soil CO2 and CH4 emissions. Furthermore, cumulative soil CH4 emission was positively significantly correlated to soil organic carbon and total carbon, suggesting that carbon component can supply energy and nutrients and benefit for soil CH4 production. Additionally, there was a significant relationship between cumulative soil CO2 emission and dissolved organic carbon, which indicated that CO2 was mainly contributed from dissolved organic carbon. Cumulative soil CO2 emission was significantly correlated with soil microbial biomass carbon, suggesting that microbial activity played an important role in CO2 emissions in Coastal Wetlands. Our results also indicate that water table level rise caused by sea level rise may contribute to the storage of soil organic carbon and produces a lower global warming potentials of CH4 and CO2 in the further climate change. Therefore, it is necessary to estimate the effect of hydrological, especially water table level on carbon cycles in Coastal Wetland when evaluating the climate–carbon feedback scenarios.
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changes in plant biomass induced by soil moisture variability drive interannual variation in the net ecosystem co2 exchange over a reclaimed Coastal Wetland
Agricultural and Forest Meteorology, 2019Co-Authors: Xiaojing Chu, Guangxuan Han, Qinghui Xing, Jianyang Xia, Baoyu Sun, Weimin SongAbstract:Abstract Changes in the timing and magnitude of precipitation is a threat to agricultural productivity and farmland carbon stocks. However, the relationship between inter-annual variations in precipitation and net ecosystem CO2 exchange (NEE) remains to be clarified, particularly when combined with water-salt transport in reclaimed Coastal Wetland. Here, based on the eddy-covariance technique, we investigated the interannual variation in carbon dioxide exchange and its control mechanism over a reclaimed Coastal Wetland of the Yellow River Delta from 2010 to 2014. The Coastal Wetland functioned as a strong sink for atmospheric CO2, with the annual NEE of −229, −175, −142, −92 and −80 g C m−2 in the 5 years from 2010 to 2014, respectively. Surprisingly, we find that large annual variation in net ecosystem exchange (NEE) can be predicted accurately using plant biomass. Plant biomass was driven by soil water content (SWC), with about 48%–80% seasonal variation of biomass attributed to SWC. During the early growing stage, high SWC accompanied with low salinity promoted plant biomass and NEE. While high SWC accompanied with increased waterlogged stress inhibited plant biomass and NEE during the middle growing stage. The same results were also observed in a field manipulation experiment over a nearby natural Coastal Wetland. Our study indicated that extreme climate accompanied with extreme drought and flooding may decrease carbon sequestration capacity of the reclaimed Coastal Wetland due to the increase in salinity.
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precipitation events reduce soil respiration in a Coastal Wetland based on four year continuous field measurements
Agricultural and Forest Meteorology, 2018Co-Authors: Guangxuan Han, Xiaojing Chu, Qinghui Xing, Baoyu Sun, Weimin Song, Jianyang XiaAbstract:Abstract Coastal Wetlands are considered as a significant sink for global carbon because their organic-rich soils. Given exposed to shallow water tables, water from groundwater is transported upward to the root zone through capillary rise, thus soil moisture in Coastal Wetlands is relatively high even when there is no precipitation. We expected that as precipitation occurred, the soils in Coastal Wetlands might become quickly saturated and lead to the development of anoxic conditions. We further hypothesized that such anoxic conditions might decrease soil respiration by limiting oxygen availability and biological activities of roots and microorganisms. Based on continuous automated soil respiration data collected in a Coastal Wetland in the Yellow River Delta over 4 years (2012–2015), the results showed that on the annual scale, cumulative soil respiration was 317, 321, 231, and 274 g C m−2 yr-1 for 2012, 2013, 2014, and 2015, respectively, with an average of 286 g C m−2 yr-1. The rate of soil respiration increased exponentially with soil temperature during each year and its two seasons (growing season and non-growing season). In addition, soil respiration was significantly related to soil moisture during the growing season, but was not affected by soil moisture during the non-growing season. After each precipitation event, soil respiration was significantly negatively correlated with soil moisture under different initial soil water contents. There was a significant positive correlation between changes in soil respiration and changes in soil moisture following precipitation events. Moreover, the increase of soil moisture following precipitation events changed the temperature response of soil respiration. Our study indicated that precipitation events could decrease soil respiration by increasing soil moisture and inducing anoxic conditions in the Coastal Wetland. Therefore, we speculate that the continuation of decreasing precipitation and increasing temperature trends in the Yellow River Delta may increase soil carbon losses in the Coastal Wetland due to the increase in soil respiration.
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dual effect of precipitation redistribution on net ecosystem co2 exchange of a Coastal Wetland in the yellow river delta
Agricultural and Forest Meteorology, 2018Co-Authors: Xiaojing Chu, Guangxuan Han, Qinghui Xing, Jianyang Xia, Baoyu SunAbstract:Abstract Hydrological regime is crucial in determining the carbon dioxide (CO2) exchange between the atmosphere and Wetlands. Seasonal redistribution of precipitation is one featured hydrological regime shift, but its impacts on ecosystem CO2 exchange in Coastal Wetlands remain unclear. Here, based on the eddy-covariance technique, we examined how the net ecosystem CO2 exchange (NEE) in a Coastal Wetland of Yellow River Delta in China differed between two years (2012 and 2013) with contrasting seasonal distribution of precipitation. The ecosystem absorbed more CO2 during the growing stage in 2013 (−268.5 g C m−2) than 2012 (−174.7 g C m−2). This difference resulted from higher NEE in the fast and middle growth stages with different reasons. In the fast growth stage, the higher mean daily NEE occurred due to more precipitation coupled with lower salt stress in 2013 (−6.3 g CO2 m−2 day−1) compared to that in 2012 (−2.2 g CO2 m−2 day−1). During the middle growth stage, the mean daily NEE in 2013 (−4.2 g CO2 m−2 day−1) was significantly higher than that in 2012 (−1.1 g CO2 m−2 day−1) because the ecosystem in 2012 suffered more waterlogged stress. This dual effect of precipitation distribution on vegetation photosynthesis was also observed in a field manipulation experiment at the same site. Our results indicated that the redistribution of precipitation among seasons would play a critical role in regulating ecosystem CO2 exchange in the Coastal Wetland. More research on the associated changes between dynamics of soil hydrology and salinity could promote the accuracy of the carbon-budget estimates in Coastal Wetlands.
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Stimulation of long-term ammonium nitrogen deposition on methanogenesis by Methanocellaceae in a Coastal Wetland.
Science of The Total Environment, 2017Co-Authors: Leilei Xiao, Baohua Xie, Jinchao Liu, Hongxia Zhang, Guangxuan Han, Oumei Wang, Fanghua LiuAbstract:Atmospheric nitrogen deposition caused by human activities has been receiving much attention. Here, after long-term simulated ammonium and nitrate nitrogen deposition (NH4Cl, KNO3, and NH4NO3) in the Yellow River Delta (YRD), a sensitive Coastal Wetland ecosystem typified by a distinct wet and dry season, methane fluxes were measured, by adopting a closed static chamber technique. The results showed that deposition of ammonium nitrogen accelerated methane emissions all year round. Ammonium nitrogen deposition transformed the YRD from a methane sink into a source during the dry season. Methanocellaceae is the only methanogen with increased abundance after the application of NH4Cl and NH4NO3, which promoted methane emissions, during the wet season. The findings suggested that Methanocellaceae may facilitate methane emissions in response to increased ammonium nitrogen deposition. Other methanogens might have profited from ammonium supplementation, such as Methanosarcinaceae. Deposition of nitrate nitrogen did not affect methane flux significantly. To the best of our knowledge, this study is the first to show that Methanocellaceae may be responsible for methane production in Coastal Wetland system. This study highlights the significant effect of ammonium nitrogen and slight effect of nitrate nitrogen on methane emission in the YRD and it will be helpful to understand the microbial mechanism responding to increased nitrogen deposition in the sensitive Coastal Wetland ecosystem.
Hao Zheng - One of the best experts on this subject based on the ideXlab platform.
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biochar induced negative carbon mineralization priming effects in a Coastal Wetland soil roles of soil aggregation and microbial modulation
Science of The Total Environment, 2018Co-Authors: Hao Zheng, Xiao Wang, Zhenyu Wang, Baoshan XingAbstract:Abstract Biochar can sequestrate carbon (C) in soils and affect native soil organic carbon (SOC) mineralization via priming effects. However, the roles of soil aggregation and microbial regulation in priming effects of biochars on SOC in Coastal Wetland soils are poorly understood. Thus, a Coastal Wetland soil (δ13C − 22‰) was separated into macro-micro aggregates (53–2000 μm, MA) and silt-clay fractions (
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biochar addition reduced net n mineralization of a Coastal Wetland soil in the yellow river delta china
Geoderma, 2016Co-Authors: Lei Chen, Jingjing Chang, Hefang Wang, Zhenyu Wang, Hao Zheng, Baoshan XingAbstract:Abstract Soil degradation has seriously threatened global soil and food security. Biochar application is a promising management option to remediate the degraded soils. However, extensive application of biochar is limited by lack of understanding the effects of biochar on nitrogen (N) mineralization in the degraded Coastal Wetland soils. Therefore, the individual or combined effects of biochar, reed stem and urea fertilizer application on N mineralization in a Coastal Wetland soil were investigated using a 150-days incubation experiment, and the underlying mechanisms were discussed. Biochar addition reduced net N mineralization, but no significant effect was observed between the treatments with different addition rates. The combined addition of the biochar and reed stem had little effect on net N mineralization because of the higher C:N ratio (45.5–49.3). However, biochar addition in combination with the urea fertilizer initially decreased net N mineralization, but slightly increased it later on. The biochar-induced reduction of net N mineralization was mainly ascribed to the increased C:N ratio and decreased urease activity. Therefore, adding N fertilizer to the biochar to enhance the delivery of N prior to its incorporation into soil, which may avoid N immobilization due to N deficiency, could be an effective strategy for remediating the degraded Coastal Wetland soils.
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effects of biochar on carbon mineralization of Coastal Wetland soils in the yellow river delta china
Ecological Engineering, 2016Co-Authors: Xianxiang Luo, Xiao Wang, Zhenyu Wang, Leyun Wang, Guocheng Liu, Hao ZhengAbstract:Abstract Biochar (BC) application for improving soil quality and carbon sequestration has generated great interest for scientists and policy makers. BC can influence soil organic carbon (SOC) mineralization through priming effects. Positive, negative or no priming effects on C mineralization has been observed following BC additions to soils. However, uncertainty still remains about the influence of biochar on SOC mineralization in the Coastal Wetland soils of the Yellow River Delta, China. Therefore, a five months of incubation experiment using the Coastal Wetland soil was conducted to investigate the effects of adding BC produced from peanut shell at 350 °C on SOC mineralization at the rates of 0% (0%BC), 0.1% (0.1%BC), 1% (1%BC) and 3% (3%BC) (w/w). BC addition increased the cumulative CO2 emissions, indicating that the cumulative SOC mineralization was enhanced in the Coastal soil by BC application. However, the increased C mineralized only accounted for 1.71%, 0.32% and 0.17% of the BC-C added in the 0.1%BC, 1%BC and 3%BC treatments, respectively. Moreover, the experimental values of SOC mineralization was much lower than that of the theoretical values in both 1%BC and 3%BC treatments, indicating that a negative priming effect occurred. This may be explained by two reasons: (1) the conversion process of SOC to dissolved inorganic C (DIC) was accelerated by BC addition, which was confirmed by SEM image; (2) the amounts of available C substrate and microorganisms decreased via the sorption of labile organic C (LOC) and microorganisms onto BC. These results suggest that BC application will enhance soil C storage in the salinized Wetland soils.
Gerard Van Den Berg - One of the best experts on this subject based on the ideXlab platform.
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Integrated Subsurface Water Solutions for Coastal Wetland Restoration through Integrated Pump&Treat and Aquifer Storage and Recovery (ASR)
Proceedings, 2018Co-Authors: Martha Perdikaki, Andreas Kallioras, Klio Monokrousou, Christoforos Christoforidis, Dimitris Iossifidis, Eri Bizani, Anastasios Zafeiropoulos, Klisthenis Dimitriadis, K.j. Raat, Gerard Van Den BergAbstract:Un-managed surface and groundwater exploitation in Coastal areas usually leads to deterioration of such sensitive ecosystems by means of water resources degradation and/or increased salinity. The Coastal partof Marathon is a typical Mediterranean hydro-environment that hosts a naturally occurring Coastal Wetland linked to a typical Coastal and today degraded hydrogeological system of a semi-arid region. A smart engineered Subsurface-Water-Solution (SWS)system composed ofan optimised Pump & Treat componentintegrated with an Aquifer Storage and Recovery (ASR) scheme in this area is envisagedcontribute to the remediationof the groundwater system and the Wetland.
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integrated subsurface water solutions for Coastal Wetland restoration through integrated pump treat and aquifer storage and recovery asr
2018Co-Authors: Martha Perdikaki, Andreas Kallioras, Klio Monokrousou, Christoforos Christoforidis, Dimitris Iossifidis, Eri Bizani, Anastasios Zafeiropoulos, Klisthenis Dimitriadis, K.j. Raat, Gerard Van Den BergAbstract:Un-managed surface and groundwater exploitation in Coastal areas usually leads to deterioration of such sensitive ecosystems by means of water resources degradation and/or increased salinity. The Coastal partof Marathon is a typical Mediterranean hydro-environment that hosts a naturally occurring Coastal Wetland linked to a typical Coastal and today degraded hydrogeological system of a semi-arid region. A smart engineered Subsurface-Water-Solution (SWS)system composed ofan optimised Pump & Treat componentintegrated with an Aquifer Storage and Recovery (ASR) scheme in this area is envisagedcontribute to the remediationof the groundwater system and the Wetland.
Baoshan Xing - One of the best experts on this subject based on the ideXlab platform.
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biochar induced negative carbon mineralization priming effects in a Coastal Wetland soil roles of soil aggregation and microbial modulation
Science of The Total Environment, 2018Co-Authors: Hao Zheng, Xiao Wang, Zhenyu Wang, Baoshan XingAbstract:Abstract Biochar can sequestrate carbon (C) in soils and affect native soil organic carbon (SOC) mineralization via priming effects. However, the roles of soil aggregation and microbial regulation in priming effects of biochars on SOC in Coastal Wetland soils are poorly understood. Thus, a Coastal Wetland soil (δ13C − 22‰) was separated into macro-micro aggregates (53–2000 μm, MA) and silt-clay fractions (
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biochar addition reduced net n mineralization of a Coastal Wetland soil in the yellow river delta china
Geoderma, 2016Co-Authors: Lei Chen, Jingjing Chang, Hefang Wang, Zhenyu Wang, Hao Zheng, Baoshan XingAbstract:Abstract Soil degradation has seriously threatened global soil and food security. Biochar application is a promising management option to remediate the degraded soils. However, extensive application of biochar is limited by lack of understanding the effects of biochar on nitrogen (N) mineralization in the degraded Coastal Wetland soils. Therefore, the individual or combined effects of biochar, reed stem and urea fertilizer application on N mineralization in a Coastal Wetland soil were investigated using a 150-days incubation experiment, and the underlying mechanisms were discussed. Biochar addition reduced net N mineralization, but no significant effect was observed between the treatments with different addition rates. The combined addition of the biochar and reed stem had little effect on net N mineralization because of the higher C:N ratio (45.5–49.3). However, biochar addition in combination with the urea fertilizer initially decreased net N mineralization, but slightly increased it later on. The biochar-induced reduction of net N mineralization was mainly ascribed to the increased C:N ratio and decreased urease activity. Therefore, adding N fertilizer to the biochar to enhance the delivery of N prior to its incorporation into soil, which may avoid N immobilization due to N deficiency, could be an effective strategy for remediating the degraded Coastal Wetland soils.
Zhenyu Wang - One of the best experts on this subject based on the ideXlab platform.
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biochar induced negative carbon mineralization priming effects in a Coastal Wetland soil roles of soil aggregation and microbial modulation
Science of The Total Environment, 2018Co-Authors: Hao Zheng, Xiao Wang, Zhenyu Wang, Baoshan XingAbstract:Abstract Biochar can sequestrate carbon (C) in soils and affect native soil organic carbon (SOC) mineralization via priming effects. However, the roles of soil aggregation and microbial regulation in priming effects of biochars on SOC in Coastal Wetland soils are poorly understood. Thus, a Coastal Wetland soil (δ13C − 22‰) was separated into macro-micro aggregates (53–2000 μm, MA) and silt-clay fractions (
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biochar addition reduced net n mineralization of a Coastal Wetland soil in the yellow river delta china
Geoderma, 2016Co-Authors: Lei Chen, Jingjing Chang, Hefang Wang, Zhenyu Wang, Hao Zheng, Baoshan XingAbstract:Abstract Soil degradation has seriously threatened global soil and food security. Biochar application is a promising management option to remediate the degraded soils. However, extensive application of biochar is limited by lack of understanding the effects of biochar on nitrogen (N) mineralization in the degraded Coastal Wetland soils. Therefore, the individual or combined effects of biochar, reed stem and urea fertilizer application on N mineralization in a Coastal Wetland soil were investigated using a 150-days incubation experiment, and the underlying mechanisms were discussed. Biochar addition reduced net N mineralization, but no significant effect was observed between the treatments with different addition rates. The combined addition of the biochar and reed stem had little effect on net N mineralization because of the higher C:N ratio (45.5–49.3). However, biochar addition in combination with the urea fertilizer initially decreased net N mineralization, but slightly increased it later on. The biochar-induced reduction of net N mineralization was mainly ascribed to the increased C:N ratio and decreased urease activity. Therefore, adding N fertilizer to the biochar to enhance the delivery of N prior to its incorporation into soil, which may avoid N immobilization due to N deficiency, could be an effective strategy for remediating the degraded Coastal Wetland soils.
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effects of biochar on carbon mineralization of Coastal Wetland soils in the yellow river delta china
Ecological Engineering, 2016Co-Authors: Xianxiang Luo, Xiao Wang, Zhenyu Wang, Leyun Wang, Guocheng Liu, Hao ZhengAbstract:Abstract Biochar (BC) application for improving soil quality and carbon sequestration has generated great interest for scientists and policy makers. BC can influence soil organic carbon (SOC) mineralization through priming effects. Positive, negative or no priming effects on C mineralization has been observed following BC additions to soils. However, uncertainty still remains about the influence of biochar on SOC mineralization in the Coastal Wetland soils of the Yellow River Delta, China. Therefore, a five months of incubation experiment using the Coastal Wetland soil was conducted to investigate the effects of adding BC produced from peanut shell at 350 °C on SOC mineralization at the rates of 0% (0%BC), 0.1% (0.1%BC), 1% (1%BC) and 3% (3%BC) (w/w). BC addition increased the cumulative CO2 emissions, indicating that the cumulative SOC mineralization was enhanced in the Coastal soil by BC application. However, the increased C mineralized only accounted for 1.71%, 0.32% and 0.17% of the BC-C added in the 0.1%BC, 1%BC and 3%BC treatments, respectively. Moreover, the experimental values of SOC mineralization was much lower than that of the theoretical values in both 1%BC and 3%BC treatments, indicating that a negative priming effect occurred. This may be explained by two reasons: (1) the conversion process of SOC to dissolved inorganic C (DIC) was accelerated by BC addition, which was confirmed by SEM image; (2) the amounts of available C substrate and microorganisms decreased via the sorption of labile organic C (LOC) and microorganisms onto BC. These results suggest that BC application will enhance soil C storage in the salinized Wetland soils.