Methane(CH_(4))is a potent greenhouse gas that has a substantial impact on global warming due to its substantial influence on the greenhouse effect.Increasing extreme precipitation events,such as drought,attributable ...Methane(CH_(4))is a potent greenhouse gas that has a substantial impact on global warming due to its substantial influence on the greenhouse effect.Increasing extreme precipitation events,such as drought,attributable to global warming that caused by greenhouse gases,exert a profound impact on the intricate biological processes associated with CH_(4) uptake.Notably,the timing of extreme drought occurrence emerges as a pivotal factor influencing CH_(4) uptake,even when the degree of drought remains constant.However,it is still unclear how the growing season regulates the response of CH_(4) uptake to extreme drought.In an effort to bridge this knowledge gap,we conducted a field manipulative experiment to evaluate the impact of extreme drought on CH_(4) uptake during early,middle,and late growing stages in a temperate steppe of Inner Mongolia Autonomous Region,China.The result showed that all extreme drought consistently exerted positive effects on CH_(4) uptake regardless of seasonal timing.However,the magnitude of this effect varied depending on the timing of season,as evidenced by a stronger effect in early growing stage than in middle and late growing stages.Besides,the pathways of CH_(4) uptake were different from seasonal timing.Extreme drought affected soil physical-chemical properties and aboveground biomass(AGB),consequently leading to changes in CH_(4) uptake.The structural equation model showed that drought both in the early and middle growing stages enhanced CH_(4) uptake due to reduced soil water content(SWC),leading to a decrease in NO_(3)–-N and an increase in pmoA abundance.However,drought in late growing stage primarily enhanced CH_(4) uptake only by decreasing SWC.Our results suggested that seasonal timing significantly contributed to regulate the impacts of extreme drought pathways and magnitudes on CH_(4) uptake.The findings can provide substantial implications for understanding how extreme droughts affect CH_(4) uptake and improve the prediction of potential ecological consequence under future climate change.展开更多
黄河流域是中国“一带一路”发展的重要经济廊道,维持黄河流域的生态健康对中国经济社会发展和生态安全具有十分重要的作用。受气候变化和人类活动的影响,黄河流域出现上游植被退化、中游水沙锐减、下游用水紧张、河口三角洲退缩等生态...黄河流域是中国“一带一路”发展的重要经济廊道,维持黄河流域的生态健康对中国经济社会发展和生态安全具有十分重要的作用。受气候变化和人类活动的影响,黄河流域出现上游植被退化、中游水沙锐减、下游用水紧张、河口三角洲退缩等生态危机,严重制约了流域内的生态文明进程和经济高质量发展。以1990—2020年间Web of Science数据库中收录的5190篇相关文献和145781条参考文献为研究样本,采用可视化知识网络分析和科学计量法,从文献产出规律、关键词共现网络和未来发展方向3个方面,多角度、深层次、定量化、可视化分析黄河流域生态水文研究现状、研究机构、载文期刊、高产作者和热点研究主题。展开更多
In the context of climate change, precipitation is predicted to become more intense at the global scale. Such change may alter soil microbial communities and the microbially mediated carbon and nitrogen dynamics. In t...In the context of climate change, precipitation is predicted to become more intense at the global scale. Such change may alter soil microbial communities and the microbially mediated carbon and nitrogen dynamics. In this study, we experimentally repackaged precipitation patterns during the growing season(from June to September) of 2012 in a semi-arid temperate steppe of the Xilin River Basin in Inner Mongolia of China, based on the 60-year growing season precipitation data. Specifically, a total amount of 240 mm simulated precipitation was assigned to experimental plots by taking the following treatments:(1) P6(6 extreme precipitation events, near the 1^(st) percentile);(2) P10(10 extreme precipitation events, near the 5^(th) percentile);(3) P16(16 moderate precipitation events, near the 50^(th) percentile); and(4) P24(24 events, 60-year average precipitation, near the 50^(th) percentile). At the end of the growing season, we analyzed soil microbial community structure and biomass, bacterial abundance, fungal abundance and bacterial composition, by using phospholipid fatty acid(PLFA), real-time quantitative polymerase chain reaction(RT-qPCR) and 16S rRNA gene clone library methods. The extreme precipitation events did not change soil microbial community structure(represented by the ratio of PLFA concentration in fungi to PLFA concentration in bacteria, and the ratio of PLFA concentration in gram-positive bacterial biomass to PLFA concentration in gram-negative bacterial biomass). However, the extreme precipitation events significantly increased soil microbial activity(represented by soil microbial biomass nitrogen and soil bacterial 16S rRNA gene copy numbers). Soil fungal community showed no significant response to precipitation events. According to the redundancy analysis, both soil microbial biomass nitrogen and soil ammonium nitrogen(NH_4-N) were found to be significant in shaping soil microbial community. Acidobacteria, Actinobacteria and Proteobacteria were the dominant phyla in soil bacterial composition, and responded differently to the extreme precipitation events. Based on the results, we concluded that the extreme precipitation events altered the overall soil microbial activity, but did not impact how the processes would occur, since soil microbial community structure remained unchanged.展开更多
The grassland in the Hindu Kush Himalayan(HKH) region is one of the large st and most biodiverse mountain grassland types in the world,and its ecosystem service functions have profound impacts on the sustainable devel...The grassland in the Hindu Kush Himalayan(HKH) region is one of the large st and most biodiverse mountain grassland types in the world,and its ecosystem service functions have profound impacts on the sustainable development of the HKH region.Monitoring the spatiotemporal distribution of grassland aboveground biomass(AGB) accurately and quantifying its response to climate change are indispensable sources of information for sustainably managing grassland ecosystems in the HKH region.In this study,a pure vegetation index model(PVIM) was applied to estimate the long-term dynamics of grassland AGB in the HKH region during 2000-2018.We further quantified the response of grassland AGB to climate change(temperature and precipitation) by partial correlation and variance partitioning analyses and then compared their differences with elevation.Our results demonstrated that the grassland AGB predicted by the PVIM had a good linear relationship with the ground sampling data.The grassland AGB distribution pattern showed a decreasing trend from east to west across the HKH region except in the southern Himalayas.From 2000 to 2018,the mean AGB of the HKH region increased at a rate of 1.57 g/(m~2·yr) and ranged from 252.9(2000) to 307.8 g/m~2(2018).AGB had a positive correlation with precipitation in more than 80% of the grassland,and temperature was positively correlated with AGB in approximately half of the region.The change in grassland AGB was more responsive to the cumulative effect of annual precipitation,while it was more sensitive to the change in temperature in the growing season;in addition,the influence of climate varied at different elevations.Moreover,compared with that of temperature,the contribution of precipitation to grassland AGB change was greater in approximately 60% of the grassland,but the differences in the contribution for each climate factor were small between the two temporal scales at elevations over 2000 m.An accurate assessment of the temporal and spatial distributions of grassland AGB and the quantification of its response to climate change are of great significance for grassland management and sustainable development in the HKH region.展开更多
基金This study was funded by the National Natural Science Foundation of China(42041005,U20A2050,U21A20240)the Weiqiao-UCAS(University of Chinese Academy of Sciences)Special Projects on Low-Carbon Technology Development(GYY-DTFZ-2022-006)the Fundamental Research Funds for the Central Universities(E1E40607).
文摘Methane(CH_(4))is a potent greenhouse gas that has a substantial impact on global warming due to its substantial influence on the greenhouse effect.Increasing extreme precipitation events,such as drought,attributable to global warming that caused by greenhouse gases,exert a profound impact on the intricate biological processes associated with CH_(4) uptake.Notably,the timing of extreme drought occurrence emerges as a pivotal factor influencing CH_(4) uptake,even when the degree of drought remains constant.However,it is still unclear how the growing season regulates the response of CH_(4) uptake to extreme drought.In an effort to bridge this knowledge gap,we conducted a field manipulative experiment to evaluate the impact of extreme drought on CH_(4) uptake during early,middle,and late growing stages in a temperate steppe of Inner Mongolia Autonomous Region,China.The result showed that all extreme drought consistently exerted positive effects on CH_(4) uptake regardless of seasonal timing.However,the magnitude of this effect varied depending on the timing of season,as evidenced by a stronger effect in early growing stage than in middle and late growing stages.Besides,the pathways of CH_(4) uptake were different from seasonal timing.Extreme drought affected soil physical-chemical properties and aboveground biomass(AGB),consequently leading to changes in CH_(4) uptake.The structural equation model showed that drought both in the early and middle growing stages enhanced CH_(4) uptake due to reduced soil water content(SWC),leading to a decrease in NO_(3)–-N and an increase in pmoA abundance.However,drought in late growing stage primarily enhanced CH_(4) uptake only by decreasing SWC.Our results suggested that seasonal timing significantly contributed to regulate the impacts of extreme drought pathways and magnitudes on CH_(4) uptake.The findings can provide substantial implications for understanding how extreme droughts affect CH_(4) uptake and improve the prediction of potential ecological consequence under future climate change.
文摘黄河流域是中国“一带一路”发展的重要经济廊道,维持黄河流域的生态健康对中国经济社会发展和生态安全具有十分重要的作用。受气候变化和人类活动的影响,黄河流域出现上游植被退化、中游水沙锐减、下游用水紧张、河口三角洲退缩等生态危机,严重制约了流域内的生态文明进程和经济高质量发展。以1990—2020年间Web of Science数据库中收录的5190篇相关文献和145781条参考文献为研究样本,采用可视化知识网络分析和科学计量法,从文献产出规律、关键词共现网络和未来发展方向3个方面,多角度、深层次、定量化、可视化分析黄河流域生态水文研究现状、研究机构、载文期刊、高产作者和热点研究主题。
基金financially supported by the Strategic Priority Research Program of the Chinese Academy of Sciences (XDA19030202)the International Cooperation and Exchange of National Natural Science Foundation of China (31761123001, 31761143018)
文摘In the context of climate change, precipitation is predicted to become more intense at the global scale. Such change may alter soil microbial communities and the microbially mediated carbon and nitrogen dynamics. In this study, we experimentally repackaged precipitation patterns during the growing season(from June to September) of 2012 in a semi-arid temperate steppe of the Xilin River Basin in Inner Mongolia of China, based on the 60-year growing season precipitation data. Specifically, a total amount of 240 mm simulated precipitation was assigned to experimental plots by taking the following treatments:(1) P6(6 extreme precipitation events, near the 1^(st) percentile);(2) P10(10 extreme precipitation events, near the 5^(th) percentile);(3) P16(16 moderate precipitation events, near the 50^(th) percentile); and(4) P24(24 events, 60-year average precipitation, near the 50^(th) percentile). At the end of the growing season, we analyzed soil microbial community structure and biomass, bacterial abundance, fungal abundance and bacterial composition, by using phospholipid fatty acid(PLFA), real-time quantitative polymerase chain reaction(RT-qPCR) and 16S rRNA gene clone library methods. The extreme precipitation events did not change soil microbial community structure(represented by the ratio of PLFA concentration in fungi to PLFA concentration in bacteria, and the ratio of PLFA concentration in gram-positive bacterial biomass to PLFA concentration in gram-negative bacterial biomass). However, the extreme precipitation events significantly increased soil microbial activity(represented by soil microbial biomass nitrogen and soil bacterial 16S rRNA gene copy numbers). Soil fungal community showed no significant response to precipitation events. According to the redundancy analysis, both soil microbial biomass nitrogen and soil ammonium nitrogen(NH_4-N) were found to be significant in shaping soil microbial community. Acidobacteria, Actinobacteria and Proteobacteria were the dominant phyla in soil bacterial composition, and responded differently to the extreme precipitation events. Based on the results, we concluded that the extreme precipitation events altered the overall soil microbial activity, but did not impact how the processes would occur, since soil microbial community structure remained unchanged.
基金Under the auspices of the Strategic Priority Research Program of the Chinese Academy of Sciences (No.XDA19030202)National Key Research and Development Program of China (No. 2020YFE0200800)+1 种基金International Cooperation and Exchange of National Natural Science Foundation of China (No. 31761143018)National Natural Science Foundation of China (No.42071344)。
文摘The grassland in the Hindu Kush Himalayan(HKH) region is one of the large st and most biodiverse mountain grassland types in the world,and its ecosystem service functions have profound impacts on the sustainable development of the HKH region.Monitoring the spatiotemporal distribution of grassland aboveground biomass(AGB) accurately and quantifying its response to climate change are indispensable sources of information for sustainably managing grassland ecosystems in the HKH region.In this study,a pure vegetation index model(PVIM) was applied to estimate the long-term dynamics of grassland AGB in the HKH region during 2000-2018.We further quantified the response of grassland AGB to climate change(temperature and precipitation) by partial correlation and variance partitioning analyses and then compared their differences with elevation.Our results demonstrated that the grassland AGB predicted by the PVIM had a good linear relationship with the ground sampling data.The grassland AGB distribution pattern showed a decreasing trend from east to west across the HKH region except in the southern Himalayas.From 2000 to 2018,the mean AGB of the HKH region increased at a rate of 1.57 g/(m~2·yr) and ranged from 252.9(2000) to 307.8 g/m~2(2018).AGB had a positive correlation with precipitation in more than 80% of the grassland,and temperature was positively correlated with AGB in approximately half of the region.The change in grassland AGB was more responsive to the cumulative effect of annual precipitation,while it was more sensitive to the change in temperature in the growing season;in addition,the influence of climate varied at different elevations.Moreover,compared with that of temperature,the contribution of precipitation to grassland AGB change was greater in approximately 60% of the grassland,but the differences in the contribution for each climate factor were small between the two temporal scales at elevations over 2000 m.An accurate assessment of the temporal and spatial distributions of grassland AGB and the quantification of its response to climate change are of great significance for grassland management and sustainable development in the HKH region.
