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Cai M, Zhang Y, Zhao G, Zhao B, Cong N, Zhu J, Zheng Z, Wu W, Duan X. Excessive climate warming exacerbates nitrogen limitation on microbial metabolism in an alpine meadow of the Tibetan Plateau: Evidence from soil ecoenzymatic stoichiometry. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 930:172731. [PMID: 38663605 DOI: 10.1016/j.scitotenv.2024.172731] [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: 11/19/2023] [Revised: 04/17/2024] [Accepted: 04/22/2024] [Indexed: 05/03/2024]
Abstract
Soil ecoenzymatic stoichiometry reflects the dynamic equilibrium between microorganism's nutrient requirements and resource availability. However, uncertainties persist regarding the key determinants of nutrient restriction in relation to microbial metabolism under varying degrees of warming. Our long-term and multi-level warming field experiment (control treatment, +0.42 °C, +1.50 °C, +2.55 °C) in a typical alpine meadow unveiled a decline in carbon (C)- and nitrogen (N)-acquired enzymes with escalating warming magnitudes, while phosphorus (P)-acquired enzymes displayed an opposite trend. Employing enzymatic stoichiometry modeling, we assessed the nutrient limitations of microbial metabolic activity and found that C and N co-limited microbial metabolic activities in the alpine meadow. Remarkably, high-level warming (+2.55 °C) exacerbated microbe N limitation, but alleviate C limitations. The structural equation modeling further indicated that alterations in soil extracellular enzyme characteristics (SES) were more effectively elucidated by microbial characteristics (microbial biomass C, N, P, and their ratios) rather than by soil nutrients (total nutrient contents and their ratios). However, the microbial control over SES diminished with higher levels of warming magnitude. Overall, our results provided novel evidence that the factors driving microbe metabolic limitation may vary with the degree of warming in Tibet alpine grasslands. Changes in nutrient demand for microorganism's metabolism in response to warming should be considered to improve nutrient management in adapting to different future warming scenarios.
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Affiliation(s)
- Mengke Cai
- Lhasa Plateau Ecosystem Research Station, Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, China
| | - Yangjian Zhang
- Lhasa Plateau Ecosystem Research Station, Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, China; College of Resources and Environment, University of Chinese Academy of Science, Beijing 100190, China.
| | - Guang Zhao
- Lhasa Plateau Ecosystem Research Station, Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, China
| | - Bo Zhao
- Lhasa Plateau Ecosystem Research Station, Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, China
| | - Nan Cong
- Lhasa Plateau Ecosystem Research Station, Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, China
| | - Juntao Zhu
- Lhasa Plateau Ecosystem Research Station, Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, China.
| | - Zhoutao Zheng
- Lhasa Plateau Ecosystem Research Station, Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, China
| | - Wenjuan Wu
- Lhasa Plateau Ecosystem Research Station, Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, China
| | - Xiaoqing Duan
- Lhasa Plateau Ecosystem Research Station, Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, China
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Chen X, Wang G, Li N, Chang R, Zhang T, Mao T, Song C, Huang K. Nitrogen dynamics of alpine swamp meadows are less responsive to climate warming than that of alpine meadows. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 928:172446. [PMID: 38621528 DOI: 10.1016/j.scitotenv.2024.172446] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2024] [Revised: 04/09/2024] [Accepted: 04/10/2024] [Indexed: 04/17/2024]
Abstract
The freeze-thaw cycle mediates permafrost soil hydrothermal status, nitrogen (N) mineralization, and loss. Furthermore, it affects root development and competition among nitrophilic and other species, shaping the pattern of N distribution in alpine ecosystems. However, the specific N dynamics during the growing season and N loss during the non-growing season in response to climate warming under low- and high-moisture conditions are not well documented. Therefore, we added 15N tracers to trace the fate of N in warmed and ambient alpine meadows and alpine swamp meadows in the permafrost region of the Qinghai-Tibet Plateau. During the growing season, warming increased 15N recovery (15Nrec) in shoots of K. humilis, litters, 0-5 and 5-20 cm roots in the alpine meadow by 149.94 % ± 52.87 %, 114.58 % ± 24.43 %, 61.11 % ± 32.27 %, and 97.12 % ± 42.92 %, respectively, while increased 15Nrec of litters by 151.55 % ± 27.06 % in the alpine swamp meadow. During the non-growing season, warming reduced 15N stored in roots by 486.77 % ± 57.90 %, though increased the 15N recovery in 5-20 cm soil depth by 76.68 % ± 39.42 % in the alpine meadow, whereas it did not affect N loss during the non-growing season in the alpine swamp meadow. Overall, warming promoted N utilization by increasing the plant N pool during the growing season, and enhanced root N loss and downward migration during the non-growing season due to the freeze-thaw process, which may result in fine root turnover and cell destruction releasing N in the alpine meadow. Conversely, the N dynamics of alpine swamp meadows were less responsive to climate warming.
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Affiliation(s)
- Xiaopeng Chen
- College of Grassland Science, Shanxi Agricultural University, Taigu 030801, China
| | - Genxu Wang
- State Key Laboratory of Hydraulics and Mountain River Engineering, College of Water Resource and Hydropower, Sichuan University, Chengdu 610065, China.
| | - Na Li
- Ecological Restoration and Biodiversity Conservation Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, China
| | - Ruiying Chang
- Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu 610041, China
| | - Tao Zhang
- Institute of New Rural Development, Guizhou University, Guiyang 550025, China
| | - Tianxu Mao
- College of Forestry, Guizhou University, Guiyang 550025, China
| | - Chunlin Song
- State Key Laboratory of Hydraulics and Mountain River Engineering, College of Water Resource and Hydropower, Sichuan University, Chengdu 610065, China
| | - Kewei Huang
- Hubei Key Laboratory of Basin Water Security, Changjiang Survey, Planning, Design and Research Co., Ltd., Wuhan 430010, China
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Liu Z, Si J, Jia B, He X, Zhou D, Wang C, Zhu X, Qin J, Ndayambaza B, Bai X. The dominant influencing factors of desertification and ecological risk changes in Qinghai Area of Qilian Mountains National Park: Climate change or human activity? JOURNAL OF ENVIRONMENTAL MANAGEMENT 2024; 362:121335. [PMID: 38833934 DOI: 10.1016/j.jenvman.2024.121335] [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: 03/07/2024] [Revised: 05/16/2024] [Accepted: 05/30/2024] [Indexed: 06/06/2024]
Abstract
Transitional features of desert environments partially determine the risks associated with ecosystems. Influenced by climate change and human activities, the variability and uncertainty of desertification levels and ecological risks in the Qinghai Area of Qilian Mountain National Park (QMNPQA) has become increasingly prominent. As a critical ecological barrier in northwest China, monitoring desertification dynamics and ecological risks is crucial for maintaining ecosystem stability. This study identifies the optimal monitoring model from four constructed desertification monitoring models and analyzes spatiotemporal changes in desertification. The spatial and temporal changes in ecological risks and their primary driving factors were analyzed using methods such as raster overlay calculation, geographic detector, cloud model, and trend analysis. The main conclusions are as follows: The desertification feature spatial model based on GNDVI-Albedo demonstrates better applicability in the study area, with an inversion accuracy of 81.24%. The levels of desertification and ecological risks in QMNPQA exhibit significant spatial heterogeneity, with a gradual decrease observed from northwest to southeast. From 2000 to 2020, there is an overall decreasing trend in desertification levels and ecological risks, with the decreasing trend area accounting for 89.82% and 85.71% respectively, mainly concentrated in the southeastern and northwestern parts of the study area. The proportion of areas with increasing trends is 4.49% and 7.05% respectively, scattered in patches in the central and southern edge areas. Surface temperature (ST), Digital Elevation Map (DEM), and Green normalized difference vegetation index (GNDVI) are the most influential factors determining the spatial distribution of ecological risks in QMNPQA. The effects of management and climatic factors on ecological risks demonstrate a significant antagonistic effect, highlighting the positive contributions of human activities in mitigating the driving effects of climate change on ecological risks. The research results can provide reference for desertification prevention and ecological quality improvement in QMNPQA.
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Affiliation(s)
- Zijin Liu
- Key Laboratory of Ecohydrology of Inland River Basin, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, 730000, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Jianhua Si
- Key Laboratory of Ecohydrology of Inland River Basin, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, 730000, China.
| | - Bing Jia
- Key Laboratory of Ecohydrology of Inland River Basin, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, 730000, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Xiaohui He
- Key Laboratory of Ecohydrology of Inland River Basin, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, 730000, China; University of Chinese Academy of Sciences, Beijing, 100049, China; Faculty of Resources and Environment, Baotou Teachers' College, Inner Mongolia University of Science and Technology, Baotou, 014030, China
| | - Dongmeng Zhou
- Key Laboratory of Ecohydrology of Inland River Basin, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, 730000, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Chunlin Wang
- Key Laboratory of Ecohydrology of Inland River Basin, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, 730000, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Xinglin Zhu
- Key Laboratory of Ecohydrology of Inland River Basin, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, 730000, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Jie Qin
- Key Laboratory of Ecohydrology of Inland River Basin, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, 730000, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Boniface Ndayambaza
- Key Laboratory of Ecohydrology of Inland River Basin, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, 730000, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Xue Bai
- Key Laboratory of Ecohydrology of Inland River Basin, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, 730000, China; University of Chinese Academy of Sciences, Beijing, 100049, China
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Zhang D, Wang H, Liu X, Ao K, He W, Wang T, Zhang M, Tong S. Latitudinal patterns and their climate drivers of the δ 13C, δ 15N, δ 34S isotope signatures of Spartina alterniflora across plant life-death status: a global analysis. FRONTIERS IN PLANT SCIENCE 2024; 15:1384914. [PMID: 38882576 PMCID: PMC11176468 DOI: 10.3389/fpls.2024.1384914] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/15/2024] [Accepted: 05/17/2024] [Indexed: 06/18/2024]
Abstract
Isotopic signatures offer new methods, approaches, and perspectives for exploring the ecological adaptability and functions of plants. We examined pattern differences in the isotopic signatures (δ 13C, δ 15N, δ 34S) of Spartina alterniflora across varying plant life-death status along geographic clines. We extracted 539 sets of isotopic data from 57 publications covering 267 sites across a latitude range of over 23.8° along coastal wetlands. Responses of isotopic signatures to climate drivers (MAT and MAP) and the internal relationships between isotopic signatures were also detected. Results showed that the δ 13C, δ 15N, and δ 34S of S. alterniflora were -13.52 ± 0.83‰, 6.16 ± 0.14‰, and 4.01 ± 6.96‰, with a range of -17.44‰ to -11.00‰, -2.40‰ to 15.30‰, and -9.60‰ to 15.80‰, respectively. The latitudinal patterns of δ 13C, δ 15N, and δ 34S in S. alterniflora were shaped as a convex curve, a concave curve, and an increasing straight line, respectively. A decreasing straight line for δ 13C within the ranges of MAT was identified under plant life status. Plant life-death status shaped two nearly parallel decreasing straight lines for δ 34S in response to MAT, resulting in a concave curve of δ 34S for live S. alterniflora in response to MAP. The δ 15N of S. alterniflora significantly decreased with increasing δ 13C of S. alterniflora, except for plant death status. The δ 13C, δ 15N, and δ 34S of S. alterniflora are consistent with plant height, stem diameter, leaf traits, etc, showing general latitudinal patterns closely related to MAT. Plant life-death status altered the δ 15N (live: 6.55 ± 2.23‰; dead: -2.76 ± 2.72‰), latitudinal patterns of S. alterniflora and their responses to MAT, demonstrating strong ecological plasticity and adaptability across the geographic clines. The findings help in understanding the responses of latitudinal patterns of the δ 13C, δ 15N, and δ 34S isotope signatures of S. alterniflora in response plant life-death status, and provide evidence of robust ecological plasticity and adaptability across geographic clines.
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Affiliation(s)
- Dongjie Zhang
- Shandong Key Laboratory of Eco-Environmental Science for the Yellow River Delta, Shandong University of Aeronautics, Binzhou, Shandong, China
| | - Hui Wang
- Shandong Key Laboratory of Eco-Environmental Science for the Yellow River Delta, Shandong University of Aeronautics, Binzhou, Shandong, China
| | - Xuepeng Liu
- Shandong Key Laboratory of Eco-Environmental Science for the Yellow River Delta, Shandong University of Aeronautics, Binzhou, Shandong, China
| | - Kang Ao
- Shandong Key Laboratory of Eco-Environmental Science for the Yellow River Delta, Shandong University of Aeronautics, Binzhou, Shandong, China
| | - Wenjun He
- Shandong Key Laboratory of Eco-Environmental Science for the Yellow River Delta, Shandong University of Aeronautics, Binzhou, Shandong, China
| | - Tongxin Wang
- School of Geographical Sciences, Northeast Normal University, Changchun, Jilin, China
| | - Mingye Zhang
- Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun, Jilin, China
| | - Shouzheng Tong
- Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun, Jilin, China
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Liu D, Song X, Hu J, Liu Y, Wang C, Henkin Z. Precipitation affects soil nitrogen fixation by regulating active diazotrophs and nitrate nitrogen in an alpine grassland of Qinghai-Tibetan Plateau. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 919:170648. [PMID: 38336078 DOI: 10.1016/j.scitotenv.2024.170648] [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: 11/26/2023] [Revised: 01/27/2024] [Accepted: 01/31/2024] [Indexed: 02/12/2024]
Abstract
Soil asymbiotic nitrogen (N) fixation provides a critical N source to support plant growth in alpine grasslands, and precipitation change is expected to lead to shifts in soil asymbiotic N fixation. However, large gaps remain in understanding the response of soil asymbiotic N fixation to precipitation gradients. Here we simulated five precipitation gradients (10 % (0.1P), 50 % (0.5P), 70 % (0.7P), 100 % (1.0P) and 150 % (1.5P) of the natural precipitation) in an alpine grassland of Qinghai-Tibetan Plateau and examined the soil nitrogenase activity and N fixation rate for each gradient. Quantitative PCR and high-throughput sequencing were used to measure the abundance and community composition of the soil nifH DNA (total diazotrophs) and nifH RNA reverse transcription (active diazotrophs) gene. Our results showed that the soil diazotrophic abundance, diversity and nifH gene expression rate peaked under the 0.5P. Soil nitrogenase activity and N fixation rate varied in the range 0.032-0.073 nmol·C2H4·g-1·h-1 and 0.008-0.022 nmol·N2·g-1·h-1 respectively, being highest under the 0.5P. The 50 % precipitation reduction enhanced the gene expression rates of Azospirillum and Halorhodospira which were likely responsible for the high N fixation potential. The 0.5P treatment also possessed a larger and more complex active diazotrophic network than the other treatments, which facilitated the resistance of diazotrophic community to environmental stress and thus maintained a high N fixation potential. The active diazotrophic abundance had the largest positive effect on soil N fixation, while nitrate nitrogen had the largest negative effect. Together, our study suggested that appropriate precipitation reduction can enhance soil N fixation through promoting the abundance of the soil active diazotrophs and decreasing soil nitrate nitrogen, and soil active diazotrophs and nitrate nitrogen should be considered in predicting soil N inputs in the alpine grassland of Qinghai-Tibetan Plateau under precipitation change.
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Affiliation(s)
- Dan Liu
- Provincial key laboratory for alpine grassland conservation and utilization on Qinghai-Tibetan Plateau, Institute of Qinghai-Tibetan Plateau Research, Southwest Minzu University, Chengdu 610041, China.
| | - Xiaoyan Song
- Provincial key laboratory for alpine grassland conservation and utilization on Qinghai-Tibetan Plateau, Institute of Qinghai-Tibetan Plateau Research, Southwest Minzu University, Chengdu 610041, China
| | - Jian Hu
- Provincial key laboratory for alpine grassland conservation and utilization on Qinghai-Tibetan Plateau, Institute of Qinghai-Tibetan Plateau Research, Southwest Minzu University, Chengdu 610041, China
| | - Yang Liu
- Provincial key laboratory for alpine grassland conservation and utilization on Qinghai-Tibetan Plateau, Institute of Qinghai-Tibetan Plateau Research, Southwest Minzu University, Chengdu 610041, China
| | - Changting Wang
- Provincial key laboratory for alpine grassland conservation and utilization on Qinghai-Tibetan Plateau, Institute of Qinghai-Tibetan Plateau Research, Southwest Minzu University, Chengdu 610041, China
| | - Zalmen Henkin
- Department of Natural Resources, Newe Ya'ar Research Center, Agricultural Research Organization, Volcani Institute, Israel
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Wang J, Xu X, Liu Y, Wang W, Ren C, Guo Y, Wang J, Wang N, He L, Zhao F. Unknown bacterial species lead to soil CO 2 emission reduction by promoting lactic fermentation in alpine meadow on the Qinghai-Tibetan Plateau. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 906:167610. [PMID: 37804990 DOI: 10.1016/j.scitotenv.2023.167610] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2023] [Revised: 09/26/2023] [Accepted: 10/04/2023] [Indexed: 10/09/2023]
Abstract
Highly variable soil microbial respiration among grasslands has been identified as a major cause of uncertainty in regional carbon (C) budget estimation in the Qinghai-Tibetan Plateau; microbial metabolism mechanisms might explain this variation, but remain elusive. Therefore, we investigated soil CO2 production in incubated soils and detected the associated functional genes at four sampling sites from two major alpine grasslands on the Qinghai-Tibetan Plateau. The results showed that the cumulative CO2 emissions from alpine meadow soils were 71 %-83 % lower than those from alpine steppe soils. Both the enriched genes abundance encoding fermentation and glycolysis (Embden-Meyerhof pathway (EMP)) and the diminished genes encoding tricarboxylic acid cycle (TCA) and phosphate pentose pathway (PPP) explained the CO2 emission reduction in the alpine meadow soils. The EMP: PPP and fermentation: TCA cycle ratios in alpine meadow soils were 1.45- and 1.50-fold higher than those in alpine steppe soils, respectively. Such shifts in metabolic pathways were primarily caused by the increasing dominance of an unknown species of Desulfobacteraceae with high glycolytic potential, carrying a higher abundance of ldh genes during fermentation. These unknown species were promoted by warmer temperatures and higher precipitation in the alpine meadows. Further studies on the unknown species would enhance our understanding and predictability of C cycling in alpine grasslands.
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Affiliation(s)
- Jieying Wang
- Shaanxi Key Laboratory of Earth Surface System and Environmental Carrying Capacity, Northwest University, Xi'an, Shaanxi 710127, China; College of Urban and Environmental Sciences, Northwest University, Xi'an, Shaanxi 710127, China
| | - Xiaofeng Xu
- Department of Biology, San Diego State University, San Diego 92182, USA
| | - Yanfang Liu
- Center of Physics and Chemistry, Department of Science and Technology, Qinghai Normal University, Xining 810008, China
| | - Wenying Wang
- Center of Physics and Chemistry, Department of Science and Technology, Qinghai Normal University, Xining 810008, China
| | - Chengjie Ren
- College of Agronomy, Northwest A&F University, Yangling 712100, Shaanxi, China
| | - Yaoxin Guo
- The College of Life Sciences, Northwest University, Xi'an 710072, Shaanxi, China
| | - Jun Wang
- Shaanxi Key Laboratory of Earth Surface System and Environmental Carrying Capacity, Northwest University, Xi'an, Shaanxi 710127, China; College of Urban and Environmental Sciences, Northwest University, Xi'an, Shaanxi 710127, China; State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water Resources, Yangling 712100, China; Carbon Neutrality College (Yulin), Northwest University, Xi'an, Shaanxi 710127, China
| | - Ninglian Wang
- Shaanxi Key Laboratory of Earth Surface System and Environmental Carrying Capacity, Northwest University, Xi'an, Shaanxi 710127, China
| | - Liyuan He
- Department of Biology, San Diego State University, San Diego 92182, USA.
| | - Fazhu Zhao
- Shaanxi Key Laboratory of Earth Surface System and Environmental Carrying Capacity, Northwest University, Xi'an, Shaanxi 710127, China; College of Urban and Environmental Sciences, Northwest University, Xi'an, Shaanxi 710127, China; Carbon Neutrality College (Yulin), Northwest University, Xi'an, Shaanxi 710127, China.
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Li X, Xu L, Li M, He N. High-resolution maps of vegetation nitrogen density on the Tibetan Plateau: An intensive field-investigation. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 904:167233. [PMID: 37739084 DOI: 10.1016/j.scitotenv.2023.167233] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Revised: 09/05/2023] [Accepted: 09/18/2023] [Indexed: 09/24/2023]
Abstract
Nitrogen (N) is a vital macronutrient in plant growth and development that plays a crucial role in the regulation of numerous physiological processes. The Tibetan Plateau is among the most species-diverse vegetation zones in the world, and is sensitive to climate change; however, research on vegetation N in the region remains limited. This study used field grid-sampling of 2040 plant communities to investigate the spatial variation and driving factors of vegetation N on the Tibetan Plateau. The results yielded an average N content, density and storage in vegetation of 8.48 mg g-1, 27.02 g m-2, and 29.84Tg, respectively. The ratio-based optimal partitioning hypothesis appears to be more suitable than the isometric allocation hypothesis to explain variation in vegetation N on the Tibetan Plateau. Variation in vegetation N density, was influenced by several environmental factors of which the most significant was radiation. Based on these results, a Random Forest model was used to predict a N density distribution map at 1 km resolution, achieving an accuracy (R2) of 0.72 (aboveground N density), 0.61 (belowground N density), and 0.69 (total vegetation N density). Trends for high densities were predicted in the southeast and low densities in the northwest of the region. Our findings and maps could be used to provide key N cycle parameters, contributing to future remote sensing, radar analyses, modeling and ecological management.
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Affiliation(s)
- Xin Li
- Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China; College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 10049, China
| | - Li Xu
- Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China.
| | - Mingxu Li
- Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China
| | - Nianpeng He
- Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China; College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 10049, China; Center for Ecological Research, Northeast Forestry University, 150040 Harbin, China.
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8
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Fang C, Verbrigghe N, Sigurdsson BD, Ostonen I, Leblans NIW, Marañón-Jiménez S, Fuchslueger L, Sigurðsson P, Meeran K, Portillo-Estrada M, Verbruggen E, Richter A, Sardans J, Peñuelas J, Bahn M, Vicca S, Janssens IA. Decadal soil warming decreased vascular plant above and belowground production in a subarctic grassland by inducing nitrogen limitation. THE NEW PHYTOLOGIST 2023; 240:565-576. [PMID: 37545200 DOI: 10.1111/nph.19177] [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: 06/24/2023] [Accepted: 07/10/2023] [Indexed: 08/08/2023]
Abstract
Below and aboveground vegetation dynamics are crucial in understanding how climate warming may affect terrestrial ecosystem carbon cycling. In contrast to aboveground biomass, the response of belowground biomass to long-term warming has been poorly studied. Here, we characterized the impacts of decadal geothermal warming at two levels (on average +3.3°C and +7.9°C) on below and aboveground plant biomass stocks and production in a subarctic grassland. Soil warming did not change standing root biomass and even decreased fine root production and reduced aboveground biomass and production. Decadal soil warming also did not significantly alter the root-shoot ratio. The linear stepwise regression model suggested that following 10 yr of soil warming, temperature was no longer the direct driver of these responses, but losses of soil N were. Soil N losses, due to warming-induced decreases in organic matter and water retention capacity, were identified as key driver of the decreased above and belowground production. The reduction in fine root production was accompanied by thinner roots with increased specific root area. These results indicate that after a decade of soil warming, plant productivity in the studied subarctic grassland was affected by soil warming mainly by the reduction in soil N.
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Affiliation(s)
- Chao Fang
- Research Center for Global Changes and Ecosystem Carbon Sequestration & Mitigation, School of Applied Meteorology, Nanjing University of Information Science and Technology, Nanjing, 210044, China
- PLECO (Plants and Ecosystems), Department of Biology, University of Antwerp, Universiteitsplein 1, Wilrijk, 2610, Belgium
| | - Niel Verbrigghe
- Flanders Research Institute for Agriculture, Fisheries and Food, Caritasstraat 39, Melle, 9090, Belgium
| | | | - Ivika Ostonen
- Institute of Ecology and Earth Sciences, University of Tartu, Tartu, 51003, Estonia
| | - Niki I W Leblans
- Climate Impacts Research Centre, Umeå University, Umeå, 90333, Sweden
| | - Sara Marañón-Jiménez
- CREAF, Cerdanyola del Vallès, Barcelona, 08193, Catalonia, Spain
- CSIC, Global Ecology Unit CREAF-CSIC-UAB, Bellaterra, Barcelona, 08193, Catalonia, Spain
- Universitat Autònoma de Barcelona, Cerdanyola del Vallès, 08193, Spain
| | - Lucia Fuchslueger
- Centre for Microbiology and Environmental Systems Science, University of Vienna, Djerassiplatz 1, 1030, Vienna, Austria
| | - Páll Sigurðsson
- Agricultural University of Iceland, Hvanneyri, Borgarnes, IS-311, Iceland
| | - Kathiravan Meeran
- Department of Ecology, University of Innsbruck, 6020, Innsbruck, Austria
| | - Miguel Portillo-Estrada
- PLECO (Plants and Ecosystems), Department of Biology, University of Antwerp, Universiteitsplein 1, Wilrijk, 2610, Belgium
| | - Erik Verbruggen
- PLECO (Plants and Ecosystems), Department of Biology, University of Antwerp, Universiteitsplein 1, Wilrijk, 2610, Belgium
| | - Andreas Richter
- Centre for Microbiology and Environmental Systems Science, University of Vienna, Djerassiplatz 1, 1030, Vienna, Austria
| | - Jordi Sardans
- CREAF, Cerdanyola del Vallès, Barcelona, 08193, Catalonia, Spain
- CSIC, Global Ecology Unit CREAF-CSIC-UAB, Bellaterra, Barcelona, 08193, Catalonia, Spain
| | - Josep Peñuelas
- CREAF, Cerdanyola del Vallès, Barcelona, 08193, Catalonia, Spain
- CSIC, Global Ecology Unit CREAF-CSIC-UAB, Bellaterra, Barcelona, 08193, Catalonia, Spain
| | - Michael Bahn
- Department of Ecology, University of Innsbruck, 6020, Innsbruck, Austria
| | - Sara Vicca
- PLECO (Plants and Ecosystems), Department of Biology, University of Antwerp, Universiteitsplein 1, Wilrijk, 2610, Belgium
| | - Ivan A Janssens
- PLECO (Plants and Ecosystems), Department of Biology, University of Antwerp, Universiteitsplein 1, Wilrijk, 2610, Belgium
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9
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Wang X, Wang S, Yang Y, Tian H, Jetten MSM, Song C, Zhu G. Hot moment of N 2O emissions in seasonally frozen peatlands. THE ISME JOURNAL 2023; 17:792-802. [PMID: 36864114 PMCID: PMC10203296 DOI: 10.1038/s41396-023-01389-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Revised: 02/15/2023] [Accepted: 02/21/2023] [Indexed: 03/04/2023]
Abstract
Since the start of the Anthropocene, northern seasonally frozen peatlands have been warming at a rate of 0.6 °C per decade, twice that of the Earth's average rate, thereby triggering increased nitrogen mineralization with subsequent potentially large losses of nitrous oxide (N2O) to the atmosphere. Here we provide evidence that seasonally frozen peatlands are important N2O emission sources in the Northern Hemisphere and the thawing periods are the hot moment of annual N2O emissions. The flux during the hot moment of thawing in spring was 1.20 ± 0.82 mg N2O m-2 d-1, significantly higher than that during the other periods (freezing, -0.12 ± 0.02 mg N2O m-2 d-1; frozen, 0.04 ± 0.04 mg N2O m-2 d-1; thawed, 0.09 ± 0.01 mg N2O m-2 d-1) or observed for other ecosystems at the same latitude in previous studies. The observed emission flux is even higher than those of tropical forests, the World's largest natural terrestrial N2O source. Furthermore, based on soil incubation with 15N and 18O isotope tracing and differential inhibitors, heterotrophic bacterial and fungal denitrification was revealed as the main source of N2O in peatland profiles (0-200 cm). Metagenomic, metatranscriptomic, and qPCR assays further revealed that seasonally frozen peatlands have high N2O emission potential, but thawing significantly stimulates expression of genes encoding N2O-producing protein complexes (hydroxylamine dehydrogenase (hao) and nitric oxide reductase (nor)), resulting in high N2O emissions during spring. This hot moment converts seasonally frozen peatlands into an important N2O emission source when it is otherwise a sink. Extrapolation of our data to all northern peatland areas reveals that the hot moment emissions could amount to approximately 0.17 Tg of N2O yr-1. However, these N2O emissions are still not routinely included in Earth system models and global IPCC assessments.
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Affiliation(s)
- Xiaomin Wang
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, 100085, Beijing, China
- University of Chinese Academy of Sciences, 100049, Beijing, China
| | - Shanyun Wang
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, 100085, Beijing, China
| | - Yuanhe Yang
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, 100093, Beijing, China
| | - Hanqin Tian
- Schiller Institute for Integrated Science and Society, Department of Earth and Environmental Sciences, Boston College, Boston, Chestnut Hill, MA 02467, USA
| | - Mike S M Jetten
- Department of Microbiology, Radboud University Nijmegen, Nijmegen, The Netherlands
| | - Changchun Song
- Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun, 130102, China
| | - Guibing Zhu
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, 100085, Beijing, China.
- University of Chinese Academy of Sciences, 100049, Beijing, China.
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10
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Ye C, Wang S, Wang Y, Zhou T, Li R. Impacts of human pressure and climate on biodiversity-multifunctionality relationships on the Qinghai-Tibetan Plateau. FRONTIERS IN PLANT SCIENCE 2023; 14:1106035. [PMID: 37332689 PMCID: PMC10270690 DOI: 10.3389/fpls.2023.1106035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Accepted: 04/28/2023] [Indexed: 06/20/2023]
Abstract
Many studies have investigated the effects of environmental context on biodiversity or multifunctionality in alpine regions, but it is uncertain how human pressure and climate may affect their relationships. Here, we combined the comparative map profile method with multivariate datasets to assess the spatial pattern of ecosystem multifunctionality and further identify the effects of human pressure and climate on the spatial distribution of biodiversity-multifunctionality relationships in alpine ecosystems of the Qinghai-Tibetan Plateau (QTP). Our results indicate that at least 93% of the areas in the study region show a positive correlation between biodiversity and ecosystem multifunctionality across the QTP. Biodiversity-multifunctionality relationships with increasing human pressure show a decreasing trend in the forest, alpine meadow, and alpine steppe ecosystems, while an opposite pattern was found in the alpine desert steppe ecosystem. More importantly, aridity significantly strengthened the synergistic relationship between biodiversity and ecosystem multifunctionality in forest and alpine meadow ecosystems. Taken together, our results provide insights into the importance of protecting and maintaining biodiversity and ecosystem multifunctionality in response to climate change and human pressure in the alpine region.
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Affiliation(s)
- Chongchong Ye
- State Key Laboratory of Earth Surface Processes and Resource Ecology, Faculty of Geographical Science, Beijing Normal University, Beijing, China
| | - Shuai Wang
- State Key Laboratory of Earth Surface Processes and Resource Ecology, Faculty of Geographical Science, Beijing Normal University, Beijing, China
| | - Yi Wang
- School of Life Sciences and State Key Lab of Biological Control, Sun Yat-sen University, Guangzhou, China
| | - Tiancai Zhou
- Synthesis Research Centre of Chinese Ecosystem Research Network, Key Laboratory of Ecosystem Network Observation and Modelling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, China
| | - Ruowei Li
- College of Grassland, Resource and Environment, Inner Mongolia Agricultural University, Hohhot, China
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11
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Wang X, Li Y, Wang L, Duan Y, Yao B, Chen Y, Cao W. Soil extracellular enzyme stoichiometry reflects microbial metabolic limitations in different desert types of northwestern China. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 874:162504. [PMID: 36863586 DOI: 10.1016/j.scitotenv.2023.162504] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Revised: 02/22/2023] [Accepted: 02/23/2023] [Indexed: 06/18/2023]
Abstract
Soil extracellular enzyme activity (EEA) stoichiometry reflects the dynamic balance between microorganism metabolic demands for resources and nutrient availability. However, variations in metabolic limitations and their driving factors in arid desert areas with oligotrophic environments remain poorly understood. In this study, we investigated sites in different desert types in western China and measured the activities of two C-acquiring enzymes (β-1,4-glucosidase and β-D-cellobiohydrolase), two N-acquiring enzymes (β-1,4-N-acetylglucosaminidase and L-leucine aminopeptidase), and one organic-P-acquiring enzyme (alkaline phosphatase) to quantify and compare the metabolic limitations of soil microorganisms based on their EEA stoichiometry. The ratios of log-transformed C-, N-, and P-acquiring enzyme activities for all deserts combined were 1:1.1:0.9, which is close to the hypothetical global mean EEA stoichiometry (1:1:1). We quantified the microbial nutrient limitation by means of vector analysis using the proportional EEAs, and found that microbial metabolism was co-limited by soil C and N. For different desert types, the microbial N limitation increased in the following order: gravel desert < sand desert < mud desert < salt desert. Overall, the study area's climate explained the largest proportion of the variation in the microbial limitation (17.9 %), followed by soil abiotic factors (6.6 %) and biological factors (5.1 %). Our results confirmed that the EEA stoichiometry method can be used in microbial resource ecology research in a range of desert types, and that the soil microorganisms maintained community-level nutrient element homeostasis by adjusting enzyme production to increase uptake of scarce nutrients even in extremely oligotrophic environments such as deserts.
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Affiliation(s)
- Xuyang Wang
- Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China; University of Chinese Academy of Sciences, Beijing 100049, China; Naiman Desertification Research Station, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Tongliao 028300, China
| | - Yuqiang Li
- Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China; University of Chinese Academy of Sciences, Beijing 100049, China; Naiman Desertification Research Station, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Tongliao 028300, China.
| | - Lilong Wang
- Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China; University of Chinese Academy of Sciences, Beijing 100049, China; Naiman Desertification Research Station, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Tongliao 028300, China
| | - Yulong Duan
- Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China; University of Chinese Academy of Sciences, Beijing 100049, China; Naiman Desertification Research Station, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Tongliao 028300, China
| | - Bo Yao
- Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China; University of Chinese Academy of Sciences, Beijing 100049, China; Naiman Desertification Research Station, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Tongliao 028300, China
| | - Yun Chen
- Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China; University of Chinese Academy of Sciences, Beijing 100049, China; Naiman Desertification Research Station, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Tongliao 028300, China
| | - Wenjie Cao
- Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China; University of Chinese Academy of Sciences, Beijing 100049, China; Naiman Desertification Research Station, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Tongliao 028300, China
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12
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Wang Y, Xiao J, Ma Y, Ding J, Chen X, Ding Z, Luo Y. Persistent and enhanced carbon sequestration capacity of alpine grasslands on Earth's Third Pole. SCIENCE ADVANCES 2023; 9:eade6875. [PMID: 37196073 DOI: 10.1126/sciadv.ade6875] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Accepted: 04/11/2023] [Indexed: 05/19/2023]
Abstract
The carbon sequestration capacity of alpine grasslands, composed of alpine meadows and steppes, in the Tibetan Plateau has an essential role in regulating the regional carbon cycle. However, inadequate understanding of its spatiotemporal dynamics and regulatory mechanisms restricts our ability to determine potential climate change impacts. We assessed the spatial and temporal patterns and mechanisms of the net ecosystem exchange (NEE) of carbon dioxide in the Tibetan Plateau. The carbon sequestration of the alpine grasslands ranged from 26.39 to 79.19 Tg C year-1 and had an increasing rate of 1.14 Tg C year-1 between 1982 and 2018. While alpine meadows were relatively strong carbon sinks, the semiarid and arid alpine steppes were nearly carbon neutral. Alpine meadow areas experienced strong increases in carbon sequestration mainly because of increasing temperatures, while alpine steppe areas had weak increases mainly due to increasing precipitation. Carbon sequestration capacity of alpine grasslands on the plateau has undergone persistent enhancement under a warmer and wetter climate.
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Affiliation(s)
- Yuyang Wang
- Land-Atmosphere Interaction and its Climatic Effects Group, State Key Laboratory of Tibetan Plateau Earth System Science, Environment and Resources (TPESER) ,, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101, China
- Sino-French Institute for Earth System Science, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China
- College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jingfeng Xiao
- Earth Systems Research Center, Institute for the Study of Earth, Oceans, and Space, University of New Hampshire, Durham, NH 03824, USA
| | - Yaoming Ma
- Land-Atmosphere Interaction and its Climatic Effects Group, State Key Laboratory of Tibetan Plateau Earth System Science, Environment and Resources (TPESER) ,, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101, China
- College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
- National Observation and Research Station for Qomolongma Special Atmospheric Processes and Environmental Changes, Dingri 858200, China
- Kathmandu Center of Research and Education, Chinese Academy of Sciences, Beijing 100101, China
- College of Atmospheric Science, Lanzhou University, Lanzhou 730000, China
| | - Jinzhi Ding
- Land-Atmosphere Interaction and its Climatic Effects Group, State Key Laboratory of Tibetan Plateau Earth System Science, Environment and Resources (TPESER) ,, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101, China
| | - Xuelong Chen
- Land-Atmosphere Interaction and its Climatic Effects Group, State Key Laboratory of Tibetan Plateau Earth System Science, Environment and Resources (TPESER) ,, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101, China
| | - Zhiyong Ding
- State Key Laboratory of Geohazard Prevention and Geoenvironment Protection, Chengdu University of Technology, Chengdu 610059, China
| | - Yiqi Luo
- School of Integrative Plant Science, Cornell University, Ithaca, NY 14853, USA
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Lamarque LJ, Félix-Faure J, Deschamps L, Lévesque E, Cusson PO, Fortier D, Giacomazzo M, Guillemette F, Paillassa J, Tremblay M, Maire V. Hydrological Regime and Plant Functional Traits Jointly Mediate the Influence of Salix spp. on Soil Organic Carbon Stocks in a High Arctic Tundra. Ecosystems 2023. [DOI: 10.1007/s10021-023-00829-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/19/2023]
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14
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Jiao C, Zhang J, Wang X, He N. Plant magnesium on the Qinghai-Tibetan Plateau: Spatial patterns and influencing factors. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 862:160743. [PMID: 36502968 DOI: 10.1016/j.scitotenv.2022.160743] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2022] [Revised: 11/19/2022] [Accepted: 12/03/2022] [Indexed: 06/17/2023]
Abstract
Magnesium (Mg) plays a crucial role in regulating plant photosynthesis and stress resistance. However, our understanding of plant Mg at the community level remains limited because of lack of systematic investigations. This study, for the first time, comprehensively evaluated community-level Mg content and density, and determined their spatial patterns and driving factors, on the Qinghai-Tibetan Plateau (TP), using data from 680 ecosystems (169 forests, 22 shrublands, 466 grasslands, and 23 deserts). Mg density was 1.01, 2.36, 1.87, and 2.26 g m-2 in leaves, branches, trunks, and roots, respectively. Notably, we generated maps of plant Mg content and density with a 1 km × 1 km resolution based on random forest models. Mg content decreased from northwest to southeast, but Mg density was higher in the east of the plateau, which reflected plant adaptive strategies to the unique radiation, oxygen, and temperature conditions (major driving factors) on the TP. Our findings provide insights into biogeochemical cycling and could facilitate the optimization of remote sensing parameters.
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Affiliation(s)
- Chaolian Jiao
- School of Forestry, Northeast Forestry University, Harbin 150040, China; Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Science, Beijing 100101, China
| | - Jiahui Zhang
- Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Science, Beijing 100101, China.
| | - Xiaochun Wang
- School of Forestry, Northeast Forestry University, Harbin 150040, China
| | - Nianpeng He
- Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Science, Beijing 100101, China; College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China
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15
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Dong K, Li W, Tang Y, Ma S, Jiang M. Co-limitation of N and P is more prevalent in the Qinghai-Tibetan Plateau grasslands. FRONTIERS IN PLANT SCIENCE 2023; 14:1140462. [PMID: 36875596 PMCID: PMC9975565 DOI: 10.3389/fpls.2023.1140462] [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: 01/09/2023] [Accepted: 01/30/2023] [Indexed: 06/18/2023]
Abstract
INTRODUCTION Over the past three decades, the view of nutrient limitation has transferred from single-nutrient limitation to multiple-nutrient limitation. On the Qinghai-Tibetan Plateau (QTP), many nitrogen (N) and phosphorus (P) addition experiments have revealed different N- or P-limited patterns at many alpine grassland sites, whereas it is not clear what the general patterns of N and P limitation across the QTP grasslands. METHODS We performed a meta-analysis, containing 107 publications, to assess how N and P constrained plant biomass and diversity in alpine grasslands across the QTP. We also tested how mean annual precipitation (MAP) and mean annual temperature (MAT) influence N and P limitations. RESULTS The findings show that plant biomass in QTP grasslands is co-limited by N and P. Single N limitation is stronger than single P limitation, and the combined positive effect of N and P addition is stronger than that of single nutrient additions. The response of biomass to N fertilization rate shows an increase firstly and then declines, and peaks at approximately 25 g N·m-2·year-1. MAP promotes the effect of N limitation on plant aboveground biomass and diminishes the effect of N limitation on belowground biomass. Meanwhile, N and P addition generally decline plant diversity. Moreover, the negative response of plant diversity to N and P co-addition is strongest than that of single nutrient additions. DISCUSSION Our results highlight that N and P co-limitation is more prevalent than N- or P-limitation alone in alpine grasslands on the QTP. Our findings provide a better understanding of nutrient limitation and management for alpine grasslands on the QTP.
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Affiliation(s)
- Kai Dong
- State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems, Gannan Grassland Ecosystem National Observation and Research Station, College of Ecology, Lanzhou University, Lanzhou, Gansu, China
- Institute of Ecology, College of Urban and Environmental Sciences, and Key Laboratory for Earth Surface Processes of the Ministry of Education, Peking University, Beijing, China
| | - Wenjin Li
- State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems, Gannan Grassland Ecosystem National Observation and Research Station, College of Ecology, Lanzhou University, Lanzhou, Gansu, China
| | - Yulong Tang
- State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems, Gannan Grassland Ecosystem National Observation and Research Station, College of Ecology, Lanzhou University, Lanzhou, Gansu, China
| | - Suhui Ma
- Institute of Ecology, College of Urban and Environmental Sciences, and Key Laboratory for Earth Surface Processes of the Ministry of Education, Peking University, Beijing, China
| | - Mengluan Jiang
- State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems, Gannan Grassland Ecosystem National Observation and Research Station, College of Ecology, Lanzhou University, Lanzhou, Gansu, China
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16
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Plant nitrogen retention in alpine grasslands of the Tibetan Plateau under multi-level nitrogen addition. Sci Rep 2023; 13:877. [PMID: 36650209 PMCID: PMC9845361 DOI: 10.1038/s41598-023-27392-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Accepted: 01/02/2023] [Indexed: 01/19/2023] Open
Abstract
Nitrogen (N) deposition might alleviate degradation of alpine grassland caused by N limitation on the Tibetan Plateau (TP). To determine such limitation and quantify the N-induced N retention in plant, a six-year fertilization experiment with six levels of N addition rates (0, 1, 2, 4, 8 and 16 g N m-2 yr-1) was conducted in the Namco alpine steppe and additional 89 experiments with multi-level N addition were also synthesized worldwide among which 27 sites were on the TP. In general, N addition promoted N retention in plants, and this increasing trend diminished at the critical N rate (Ncr). The maximum N retention capacity (MNRC) of plants at Ncr was strongly correlated with initial aboveground net primary productivity with a slope of 0.02, and the MNRC of grasslands globally ranged from 0.35 to 42.59 g N m-2 yr-1, approximately account for 39% of Ncr. Tibetan alpine grassland had a low average MNRC (2.24 g N m-2 yr-1) with distinct regional characteristic, which was much lower in the western TP (0.80 g N m-2 yr-1) than the eastern TP (4.10 g N m-2 yr-1). Our results inferred 0.33-1.21 Tg N yr-1 (0.22-0.79 g N m-2 yr-1) can be retained and 5.65-20.11 Tg C yr-1 (3.67-13.06 g C m-2 yr-1) can be gained by Tibetan alpine grasslands under current N deposition level. With the aggravation of N deposition, the alpine steppe ecosystem might continuously absorb N and C until N deposition reaches Ncr.
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17
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Microbiogeochemical Traits to Identify Nitrogen Hotspots in Permafrost Regions. NITROGEN 2022. [DOI: 10.3390/nitrogen3030031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Permafrost-affected tundra soils are large carbon (C) and nitrogen (N) reservoirs. However, N is largely bound in soil organic matter (SOM), and ecosystems generally have low N availability. Therefore, microbial induced N-cycling processes and N losses were considered negligible. Recent studies show that microbial N processing rates, inorganic N availability, and lateral N losses from thawing permafrost increase when vegetation cover is disturbed, resulting in reduced N uptake or increased N input from thawing permafrost. In this review, we describe currently known N hotspots, particularly bare patches in permafrost peatland or permafrost soils affected by thermokarst, and their microbiogeochemical characteristics, and present evidence for previously unrecorded N hotspots in the tundra. We summarize the current understanding of microbial N cycling processes that promote the release of the potent greenhouse gas (GHG) nitrous oxide (N2O) and the translocation of inorganic N from terrestrial into aquatic ecosystems. We suggest that certain soil characteristics and microbial traits can be used as indicators of N availability and N losses. Identifying N hotspots in permafrost soils is key to assessing the potential for N release from permafrost-affected soils under global warming, as well as the impact of increased N availability on emissions of carbon-containing GHGs.
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Pessi IS, Viitamäki S, Virkkala AM, Eronen-Rasimus E, Delmont TO, Marushchak ME, Luoto M, Hultman J. In-depth characterization of denitrifier communities across different soil ecosystems in the tundra. ENVIRONMENTAL MICROBIOME 2022; 17:30. [PMID: 35690846 PMCID: PMC9188126 DOI: 10.1186/s40793-022-00424-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Accepted: 06/03/2022] [Indexed: 06/15/2023]
Abstract
BACKGROUND In contrast to earlier assumptions, there is now mounting evidence for the role of tundra soils as important sources of the greenhouse gas nitrous oxide (N2O). However, the microorganisms involved in the cycling of N2O in this system remain largely uncharacterized. Since tundra soils are variable sources and sinks of N2O, we aimed at investigating differences in community structure across different soil ecosystems in the tundra. RESULTS We analysed 1.4 Tb of metagenomic data from soils in northern Finland covering a range of ecosystems from dry upland soils to water-logged fens and obtained 796 manually binned and curated metagenome-assembled genomes (MAGs). We then searched for MAGs harbouring genes involved in denitrification, an important process driving N2O emissions. Communities of potential denitrifiers were dominated by microorganisms with truncated denitrification pathways (i.e., lacking one or more denitrification genes) and differed across soil ecosystems. Upland soils showed a strong N2O sink potential and were dominated by members of the Alphaproteobacteria such as Bradyrhizobium and Reyranella. Fens, which had in general net-zero N2O fluxes, had a high abundance of poorly characterized taxa affiliated with the Chloroflexota lineage Ellin6529 and the Acidobacteriota subdivision Gp23. CONCLUSIONS By coupling an in-depth characterization of microbial communities with in situ measurements of N2O fluxes, our results suggest that the observed spatial patterns of N2O fluxes in the tundra are related to differences in the composition of denitrifier communities.
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Affiliation(s)
- Igor S. Pessi
- Department of Microbiology, University of Helsinki, Viikinkaari 9, 00014 Helsinki, Finland
- Helsinki Institute of Sustainability Science (HELSUS), Yliopistonkatu 3, 00014 Helsinki, Finland
| | - Sirja Viitamäki
- Department of Microbiology, University of Helsinki, Viikinkaari 9, 00014 Helsinki, Finland
| | - Anna-Maria Virkkala
- Woodwell Climate Research Center, 149 Woods Hole Road, Falmouth, MA 02540-1644 USA
- Department of Geosciences and Geography, University of Helsinki, Gustaf Hällströmin katu 2, 00014 Helsinki, Finland
| | - Eeva Eronen-Rasimus
- Department of Microbiology, University of Helsinki, Viikinkaari 9, 00014 Helsinki, Finland
- Marine Research Centre, Finnish Environment Institute (SYKE), Agnes Sjöbergin katu 2, 00790 Helsinki, Finland
| | - Tom O. Delmont
- Génomique Métabolique, Genoscope, Institut François-Jacob, CEA, CNRS, Université d’Evry, Université Paris-Saclay, 91057 Evry, France
| | - Maija E. Marushchak
- Department of Biological and Environmental Science, University of Jyväskylä, 40014 Jyväskylä, Finland
- Department of Environmental and Biological Sciences, University of Eastern Finland, 70211 Kuopio, Finland
| | - Miska Luoto
- Department of Geosciences and Geography, University of Helsinki, Gustaf Hällströmin katu 2, 00014 Helsinki, Finland
| | - Jenni Hultman
- Department of Microbiology, University of Helsinki, Viikinkaari 9, 00014 Helsinki, Finland
- Helsinki Institute of Sustainability Science (HELSUS), Yliopistonkatu 3, 00014 Helsinki, Finland
- Natural Resources Institute Finland (LUKE), Latokartanonkaari 9, 00790 Helsinki, Finland
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Wu D, Deng L, Sun Y, Wang R, Zhang L, Wang R, Song Y, Gao Z, Haider H, Wang Y, Hou L, Liu M. Climate warming, but not Spartina alterniflora invasion, enhances wetland soil HONO and NO x emissions. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 823:153710. [PMID: 35149064 DOI: 10.1016/j.scitotenv.2022.153710] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Revised: 01/27/2022] [Accepted: 02/02/2022] [Indexed: 06/14/2023]
Abstract
Climate warming and invasive plant growth (plant invasion) may aggravate air pollution by affecting soil nitrogen (N) cycling and the emissions of reactive N gases, such as nitrous acid (HONO) and nitrogen oxides (NOx). However, little is known about the response of soil NOy (HONO + NOx) emissions and microbial functional genes to the interaction of climate warming and plant invasion. Here, we found that experimental warming (approximately 1.5 °C), but not Spartina alterniflora invasion, increased NOy emissions (0-140 ng N m-2 s-1) of treated wetland soils by 4-10 fold. Warming also decreased soil archaeal and fungal richness and diversity, shifted their community structure (e.g., decreased the archaeal classes Thermoplasmata and Iainarchaeia, and increased the archaeal genus Candidatus Nitrosoarchaeum, and the fungal classes Saccharomycetes and Tritirachiomycetes), and decreased the overall abundance of soil N cycling genes. Structural equation modeling revealed that warming-associated changes in edaphic factors and the microbial N cycling potential are responsible for the observed increase in soil NOy emissions. Collectively, the results showed that climate warming accelerates soil N cycling by stimulating large soil HONO and NOx emissions, and influences air quality by contributing to atmospheric reactive N and ozone cycling.
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Affiliation(s)
- Dianming Wu
- Key Laboratory of Geographic Information Science (Ministry of Education), School of Geographic Sciences, East China Normal University, 200241 Shanghai, China; Institute of Eco-Chongming (IEC), 202162 Shanghai, China.
| | - Lingling Deng
- Key Laboratory of Geographic Information Science (Ministry of Education), School of Geographic Sciences, East China Normal University, 200241 Shanghai, China
| | - Yihua Sun
- Shenzhen Key Laboratory of Marine Microbiome Engineering, Institute for Advanced Study, Shenzhen University, 518060 Shenzhen, China
| | - Ruhai Wang
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of soil Sciences, Chinese Academy of Sciences, 210008 Nanjing, China
| | - Li Zhang
- School of Resources and Environment, Anhui Agricultural University, 230036 Hefei, China
| | - Rui Wang
- Key Laboratory of Geographic Information Science (Ministry of Education), School of Geographic Sciences, East China Normal University, 200241 Shanghai, China
| | - Yaqi Song
- Key Laboratory of Geographic Information Science (Ministry of Education), School of Geographic Sciences, East China Normal University, 200241 Shanghai, China; College of Biology and the Environment, Co-Innovation Center for the Sustainable Forestry in Southern China, Nanjing Forestry University, 210037 Nanjing, China
| | - Zhiwei Gao
- Key Laboratory of Geographic Information Science (Ministry of Education), School of Geographic Sciences, East China Normal University, 200241 Shanghai, China
| | - Haroon Haider
- Key Laboratory of Geographic Information Science (Ministry of Education), School of Geographic Sciences, East China Normal University, 200241 Shanghai, China
| | - Yue Wang
- Key Laboratory of Geographic Information Science (Ministry of Education), School of Geographic Sciences, East China Normal University, 200241 Shanghai, China
| | - Lijun Hou
- State Key Laboratory of Estuarine and Coastal Research, East China Normal University, 200241 Shanghai, China
| | - Min Liu
- Key Laboratory of Geographic Information Science (Ministry of Education), School of Geographic Sciences, East China Normal University, 200241 Shanghai, China; Institute of Eco-Chongming (IEC), 202162 Shanghai, China
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20
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Mason RE, Craine JM, Lany NK, Jonard M, Ollinger SV, Groffman PM, Fulweiler RW, Angerer J, Read QD, Reich PB, Templer PH, Elmore AJ. Evidence, causes, and consequences of declining nitrogen availability in terrestrial ecosystems. Science 2022; 376:eabh3767. [PMID: 35420945 DOI: 10.1126/science.abh3767] [Citation(s) in RCA: 43] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The productivity of ecosystems and their capacity to support life depends on access to reactive nitrogen (N). Over the past century, humans have more than doubled the global supply of reactive N through industrial and agricultural activities. However, long-term records demonstrate that N availability is declining in many regions of the world. Reactive N inputs are not evenly distributed, and global changes-including elevated atmospheric carbon dioxide (CO2) levels and rising temperatures-are affecting ecosystem N supply relative to demand. Declining N availability is constraining primary productivity, contributing to lower leaf N concentrations, and reducing the quality of herbivore diets in many ecosystems. We outline the current state of knowledge about declining N availability and propose actions aimed at characterizing and responding to this emerging challenge.
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Affiliation(s)
- Rachel E Mason
- National Socio-Environmental Synthesis Center, Annapolis, MD, USA
| | | | - Nina K Lany
- Northern Research Station, USDA Forest Service, Durham, NH, USA
| | - Mathieu Jonard
- Earth and Life Institute, Université catholique de Louvain, Louvain-la-Neuve, Belgium
| | - Scott V Ollinger
- Earth Systems Research Center, University of New Hampshire, Durham, NH, USA
| | - Peter M Groffman
- Advanced Science Research Center, The Graduate Center, City University of New York, New York, NY, USA.,Cary Institute of Ecosystem Studies, Millbrook, NY, USA
| | - Robinson W Fulweiler
- Department of Earth and Environment, Boston University, Boston, MA, USA.,Department of Biology, Boston University, Boston, MA, USA
| | - Jay Angerer
- Fort Keogh Livestock and Range Research Laboratory, USDA Agricultural Research Service, Miles City, MT, USA
| | - Quentin D Read
- National Socio-Environmental Synthesis Center, Annapolis, MD, USA
| | - Peter B Reich
- Department of Forest Resources, University of Minnesota, St. Paul, MN, USA.,Institute for Global Change Biology and School for Environment and Sustainability, University of Michigan, Ann Arbor, MI, USA.,Hawkesbury Institute for the Environment, Western Sydney University, Penrith, New South Wales, Australia
| | | | - Andrew J Elmore
- National Socio-Environmental Synthesis Center, Annapolis, MD, USA.,Appalachian Laboratory, University of Maryland Center for Environmental Science, Frostburg, MD, USA
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21
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Sipes K, Paul R, Fine A, Li P, Liang R, Boike J, Onstott TC, Vishnivetskaya TA, Schaeffer S, Lloyd KG. Permafrost Active Layer Microbes From Ny Ålesund, Svalbard (79°N) Show Autotrophic and Heterotrophic Metabolisms With Diverse Carbon-Degrading Enzymes. Front Microbiol 2022; 12:757812. [PMID: 35185810 PMCID: PMC8851200 DOI: 10.3389/fmicb.2021.757812] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Accepted: 11/24/2021] [Indexed: 02/02/2023] Open
Abstract
The active layer of permafrost in Ny Ålesund, Svalbard (79°N) around the Bayelva River in the Leirhaugen glacier moraine is measured as a small net carbon sink at the brink of becoming a carbon source. In many permafrost-dominating ecosystems, microbes in the active layers have been shown to drive organic matter degradation and greenhouse gas production, creating positive feedback on climate change. However, the microbial metabolisms linking the environmental geochemical processes and the populations that perform them have not been fully characterized. In this paper, we present geochemical, enzymatic, and isotopic data paired with 10 Pseudomonas sp. cultures and metagenomic libraries of two active layer soil cores (BPF1 and BPF2) from Ny Ålesund, Svalbard, (79°N). Relative to BPF1, BPF2 had statistically higher C/N ratios (15 ± 1 for BPF1 vs. 29 ± 10 for BPF2; n = 30, p < 10–5), statistically lower organic carbon (2% ± 0.6% for BPF1 vs. 1.6% ± 0.4% for BPF2, p < 0.02), statistically lower nitrogen (0.1% ± 0.03% for BPF1 vs. 0.07% ± 0.02% for BPF2, p < 10–6). The d13C values for inorganic carbon did not correlate with those of organic carbon in BPF2, suggesting lower heterotrophic respiration. An increase in the δ13C of inorganic carbon with depth either reflects an autotrophic signal or mixing between a heterotrophic source at the surface and a lithotrophic source at depth. Potential enzyme activity of xylosidase and N-acetyl-β-D-glucosaminidase increases twofold at 15°C, relative to 25°C, indicating cold adaptation in the cultures and bulk soil. Potential enzyme activity of leucine aminopeptidase across soils and cultures was two orders of magnitude higher than other tested enzymes, implying that organisms use leucine as a nitrogen and carbon source in this nutrient-limited environment. Besides demonstrating large variability in carbon compositions of permafrost active layer soils only ∼84 m apart, results suggest that the Svalbard active layer microbes are often limited by organic carbon or nitrogen availability and have adaptations to the current environment, and metabolic flexibility to adapt to the warming climate.
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Affiliation(s)
- Katie Sipes
- Microbiology Department, University of Tennessee, Knoxville, Knoxville, TN, United States
| | - Raegan Paul
- Microbiology Department, University of Tennessee, Knoxville, Knoxville, TN, United States
| | - Aubrey Fine
- Department of Biosystems Engineering and Soil Science, University of Tennessee, Knoxville, Knoxville, TN, United States
| | - Peibo Li
- Microbiology Department, University of Tennessee, Knoxville, Knoxville, TN, United States
| | - Renxing Liang
- Department of Geosciences, Princeton University, Princeton, NJ, United States
| | - Julia Boike
- Alfred Wegener Institute, Potsdam, Germany.,Geography Department, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Tullis C Onstott
- Department of Geosciences, Princeton University, Princeton, NJ, United States
| | - Tatiana A Vishnivetskaya
- Center for Environmental Biotechnology, University of Tennessee, Knoxville, Knoxville, TN, United States
| | - Sean Schaeffer
- Department of Biosystems Engineering and Soil Science, University of Tennessee, Knoxville, Knoxville, TN, United States
| | - Karen G Lloyd
- Microbiology Department, University of Tennessee, Knoxville, Knoxville, TN, United States
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22
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Unexpectedly minor nitrous oxide emissions from fluvial networks draining permafrost catchments of the East Qinghai-Tibet Plateau. Nat Commun 2022; 13:950. [PMID: 35177650 PMCID: PMC8854393 DOI: 10.1038/s41467-022-28651-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Accepted: 01/27/2022] [Indexed: 11/08/2022] Open
Abstract
Streams and rivers emit substantial amounts of nitrous oxide (N2O) and are therefore an essential component of global nitrogen (N) cycle. Permafrost soils store a large reservoir of dormant N that, upon thawing, can enter fluvial networks and partly degrade to N2O, yet the role of waterborne release of N2O in permafrost regions is unclear. Here we report N2O concentrations and fluxes during different seasons between 2016 and 2018 in four watersheds on the East Qinghai-Tibet Plateau. Thawing permafrost soils are known to emit N2O at a high rate, but permafrost rivers draining the East Qinghai-Tibet Plateau behave as unexpectedly minor sources of atmospheric N2O. Such low N2O fluxes are associated with low riverine dissolved inorganic N (DIN) after terrestrial plant uptake, unfavorable conditions for N2O generation via denitrification, and low N2O yield due to a small ratio of nitrite reductase: nitrous oxide reductase in these rivers. We estimate fluvial N2O emissions of 0.432 - 0.463 Gg N2O-N yr-1 from permafrost landscapes on the entire Qinghai-Tibet Plateau, which is marginal (~0.15%) given their areal contribution to global streams and rivers (0.7%). However, we suggest that these permafrost-affected rivers can shift from minor sources to strong emitters in the warmer future, likely giving rise to the permafrost non-carbon feedback that intensifies warming.
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23
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He M, Fang K, Chen L, Feng X, Qin S, Kou D, He H, Liang C, Yang Y. Depth-dependent drivers of soil microbial necromass carbon across Tibetan alpine grasslands. GLOBAL CHANGE BIOLOGY 2022; 28:936-949. [PMID: 34726326 DOI: 10.1111/gcb.15969] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Revised: 09/27/2021] [Accepted: 10/20/2021] [Indexed: 06/13/2023]
Abstract
Microbial necromass carbon (C) has been considered an important contributor to persistent soil C pool. However, there still lacks large-scale systematic observations on microbial necromass C in different soil layers, particularly for alpine ecosystems. Besides, it is still unclear whether the relative importance of biotic and abiotic variables such as plant C input and mineral properties in regulating microbial necromass C would change with soil depth. Based on the combination of large-scale sampling along a ~2200 km transect across Tibetan alpine grasslands and biomarker analysis, together with a global data synthesis across grassland ecosystems, we observed a relatively low proportion of microbial-derived C in Tibetan alpine grasslands compared to global grasslands (topsoil: 45.4% vs. 58.1%; subsoil: 41.7% vs. 53.7%). We also found that major determinants of microbial necromass C depended on soil depth. In topsoil, both plant C input and mineral protection exerted dominant effects on microbial necromass C. However, in subsoil, the physico-chemical protection provided by soil clay particles, iron-aluminum oxides, and exchangeable calcium dominantly facilitated the preservation of microbial necromass C. The differential drivers over microbial necromass C between soil depths should be considered in Earth system models for accurately forecasting soil C dynamics and its potential feedback to global warming.
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Affiliation(s)
- Mei He
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, China
| | - Kai Fang
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Leiyi Chen
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, China
| | - Xuehui Feng
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Shuqi Qin
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Dan Kou
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, China
- Department of Environmental and Biological Sciences, University of Eastern Finland, Kuopio, Finland
| | - Hongbo He
- Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, China
| | - Chao Liang
- Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, China
| | - Yuanhe Yang
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
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24
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Hu Y, Guy RD, Soolanayakanahally RY. Genotypic variation in C and N isotope discrimination suggests local adaptation of heart-leaved willow. TREE PHYSIOLOGY 2022; 42:32-43. [PMID: 33517390 DOI: 10.1093/treephys/tpab010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2020] [Accepted: 01/18/2021] [Indexed: 06/12/2023]
Abstract
Plants acquire multiple resources from the environment and may need to adjust and/or balance their respective resource-use efficiencies to maximize grow and survival, in a locally adaptive manner. In this study, tissue and whole-plant carbon (C) isotopic composition (δ13C) and carbon/nitrogen (C/N) ratios provided long-term measures of use efficiencies for water (WUE) and nitrogen (NUE), and a nitrogen (N) isotopic composition (δ15N)-based mass balance model was used to estimate traits related to N uptake and assimilation in heart-leaved willow (Salix eriocephala Michx.). In an initial common garden experiment consisting of 34 populations, we found population-level variation in δ13C, C/N ratio and δ15N, indicating different patterns in WUE, NUE and N uptake and assimilation. Although there was no relationship between foliar δ13C and C/N ratios among populations, there was a significant negative correlation between these measures across all individuals, implying a genetic and/or plastic trade-off between WUE and NUE not associated with local adaptation. To eliminate any environmental effect, we grew a subset of 21 genotypes hydroponically with nitrate as the sole N source and detected significant variation in δ13C, δ15N and C/N ratios. Variation in δ15N was mainly due to genotypic differences in the nitrate efflux/influx ratio (E/I) at the root. Both experiments suggested clinal variation in δ15N (and thus N uptake efficiency) with latitude of origin, which may relate to water availability and could contribute to global patterns in ecosystem δ15N. There was a tendency for genotypes with higher WUE to come from more water-replete sites with shorter and cooler growing seasons. We found that δ13C, C/N ratio and E/I were not inter-correlated, suggesting that the selection of growth, WUE, NUE and N uptake efficiency can occur without trade-off.
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Affiliation(s)
- Yi Hu
- Department of Forest and Conservation Sciences, Faculty of Forestry, University of British Columbia, Forest Sciences Centre, 2424 Main Mall, Vancouver, BC V6T 1Z4, Canada
| | - Robert D Guy
- Department of Forest and Conservation Sciences, Faculty of Forestry, University of British Columbia, Forest Sciences Centre, 2424 Main Mall, Vancouver, BC V6T 1Z4, Canada
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25
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Li X, Li M, Xu L, Liu C, Zhao W, Cheng C, He N. Allometry and Distribution of Nitrogen in Natural Plant Communities of the Tibetan Plateau. FRONTIERS IN PLANT SCIENCE 2022; 13:845813. [PMID: 35360321 PMCID: PMC8963499 DOI: 10.3389/fpls.2022.845813] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Accepted: 02/10/2022] [Indexed: 05/02/2023]
Abstract
Nitrogen (N) is an important element for most terrestrial ecosystems; its variation among different plant organs, and allocation mechanisms are the basis for the structural stability and functional optimization of natural plant communities. The nature of spatial variations of N and its allocation mechanisms in plants in the Tibetan Plateau-known as the world's third pole-have not been reported on a large scale. In this study, we consistently investigated the N content in different organs of plants in 1564 natural community plots in Tibet Plateau, using a standard spatial-grid sampling setup. On average, the N content was estimated to be 19.21, 4.12, 1.14, and 10.86 mg g-1 in the leaf, branch, trunk, and root, respectively, with small spatial variations. Among organs in communities, leaves were the most active, and had the highest N content, independent of the spatial location; as for vegetation type, communities dominated by herbaceous plants had higher N content than those dominated by woody plants. Furthermore, the allocation of N among different plant organs was allometric, and not significantly influenced by vegetation types and environmental factors; the homeostasis of N was also not affected much by the environment, and varied among the plant organs. In addition, the N allocation strategy within Tibet Plateau for different plant organs was observed to be consistent with that in China. Our findings systematically explore for the first time, the spatial variations in N and allometric mechanisms in natural plant communities in Tibet Plateau and establish a spatial-parameters database to optimize N cycle models.
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Affiliation(s)
- Xin Li
- Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, China
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, China
| | - Mingxu Li
- Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, China
- *Correspondence: Mingxu Li,
| | - Li Xu
- Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, China
| | - Congcong Liu
- Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, China
| | - Wenzong Zhao
- College of Life and Environmental Sciences, Minzu University of China, Beijing, China
| | - Changjin Cheng
- School of Ecology and Nature Conservation, Beijing Forestry University, Beijing, China
| | - Nianpeng He
- Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, China
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, China
- Center for Ecological Research, Northeast Forestry University, Harbin, China
- Nianpeng He,
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26
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Chen H, Kong W, Shi Q, Wang F, He C, Wu J, Lin Q, Zhang X, Zhu Y, Liang C, Luo Y. Patterns and drivers of the degradability of dissolved organic matter in dryland soils on the Tibetan Plateau. J Appl Ecol 2021. [DOI: 10.1111/1365-2664.14105] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Hao Chen
- State Key Laboratory of Tibetan Plateau Earth System, Resources and Environment (TPESRE), Institute of Tibetan Plateau Research Chinese Academy of Sciences Beijing China
- School of Agriculture Sun Yat‐sen University Guangzhou China
- Key Laboratory of Alpine Ecology, Institute of Tibetan Plateau Chinese Academy of Sciences Beijing China
| | - Weidong Kong
- State Key Laboratory of Tibetan Plateau Earth System, Resources and Environment (TPESRE), Institute of Tibetan Plateau Research Chinese Academy of Sciences Beijing China
- Key Laboratory of Alpine Ecology, Institute of Tibetan Plateau Chinese Academy of Sciences Beijing China
- College of Resources and Environment University of Chinese Academy of Sciences Beijing China
| | - Quan Shi
- State Key Laboratory of Heavy Oil Processing China University of Petroleum Beijing China
| | - Fei Wang
- State Key Laboratory of Tibetan Plateau Earth System, Resources and Environment (TPESRE), Institute of Tibetan Plateau Research Chinese Academy of Sciences Beijing China
- College of Resources and Environment University of Chinese Academy of Sciences Beijing China
| | - Chen He
- State Key Laboratory of Heavy Oil Processing China University of Petroleum Beijing China
| | - Jianshuang Wu
- Institute of Environment and Sustainable Development in Agriculture Chinese Academy of Agricultural Sciences Beijing China
- Key Laboratory of Ecosystem Network Observation and Modeling Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences Beijing China
| | - Qimei Lin
- College of Land Science and Technology China Agricultural University Beijing China
| | - Xianzhou Zhang
- Key Laboratory of Ecosystem Network Observation and Modeling Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences Beijing China
| | - Yong‐Guan Zhu
- Research Center for Eco‐Environmental Sciences Chinese Academy of Sciences Beijing China
| | - Chao Liang
- Institute of Applied Ecology Chinese Academy of Sciences Shenyang China
| | - Yu Luo
- Key Laboratory of Agricultural Resources and Environment Zhejiang University Hangzhou China
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27
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Wang F, Liu S, Liu Y, Sun Y, Yu L, Wang Q, Dong Y, Beazley R. Long-term dynamics of nitrogen flow in a typical agricultural and pastoral region on the Qinghai-Tibet Plateau and its optimization strategy. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2021; 288:117684. [PMID: 34252713 DOI: 10.1016/j.envpol.2021.117684] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Revised: 06/24/2021] [Accepted: 06/27/2021] [Indexed: 06/13/2023]
Abstract
Nitrogen (N) plays a central role in livestock development and food production in agricultural and pastoral regions, while its flow and loss can affect environmental quality, biodiversity and human health. A comprehensive understanding of the sources, patterns and drivers of N flow helps to alleviate its negative effects and promote sustainable management. We developed a county-scale N flow model to quantitatively analyze the N use efficiency (NUE), N losses and their driving forces in the food production and consumption system (FCPS) on the Qinghai-Tibet Plateau (QTP). More sustainable N utilization was further investigated through scenario analyses. Our results revealed that N fluxes doubled from 1998 to 2018 to maintain the growing demands for human food production and consumption in Ledu County, which was related to the increasing N losses to the atmosphere and water environment. The surging N fluxes greatly changed the N distribution pattern, resulting in a relatively low NUE (mean value: 29.41%) in the crop-production subsystem (CPS) and a relatively high NUE (mean value: 23.50%) in the livestock-breeding subsystem (LBS). The CPS contributed the most to the N losses. The urban population, animal-derived consumption, crop planting structure, imported fodder and N fertilizer application level were closely associated with N losses. The scenario analysis indicated that combined reasonable changes in planting structure, precision animal feeding, fertilizer management, diets and conversion of cropland into pasture could reduce N losses in 2030 to 5%-61% of Business as usual level. Our results highlighted the strong anthropogenic impact on the N flow of food production and consumption and suggested a sustainable N flow management strategy to harmonize the relationship between N flow and anthropogenically driven factors on the QTP.
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Affiliation(s)
- Fangfang Wang
- State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing, 100875, China
| | - Shiliang Liu
- State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing, 100875, China.
| | - Yixuan Liu
- State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing, 100875, China
| | - Yongxiu Sun
- State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing, 100875, China
| | - Lu Yu
- State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing, 100875, China
| | - Qingbo Wang
- State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing, 100875, China
| | - Yuhong Dong
- Research Institute of Forestry, Chinese Academy of Forestry, Beijing, 100091, China
| | - Robert Beazley
- Department of Natural Resources, College of Agriculture and Life Sciences, Fernow Hall 302, Cornell University, Ithaca, NY, 14853, USA
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28
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Gao W, Sun W, Xu X. Permafrost response to temperature rise in carbon and nutrient cycling: Effects from habitat-specific conditions and factors of warming. Ecol Evol 2021; 11:16021-16033. [PMID: 34824808 PMCID: PMC8601908 DOI: 10.1002/ece3.8271] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Revised: 09/30/2021] [Accepted: 10/12/2021] [Indexed: 11/06/2022] Open
Abstract
Permafrost is experiencing climate warming at a rate that is two times faster than the rest of the Earth's surface. However, it is still lack of a quantitative basis for predicting the functional stability of permafrost ecosystems in carbon (C) and nutrient cycling. We compiled the data of 708 observations from 89 air-warming experiments in the Northern Hemisphere and characterized the general effects of temperature increase on permafrost C exchange and balance, biomass production, microbial biomass, soil nutrients, and vegetation N dynamics through a meta-analysis. Also, an investigation was made on how responses might change with habitat-specific (e.g., plant functional groups and soil moisture status) conditions and warming variables (e.g., warming phases, levels, and timing). The net ecosystem C exchange (NEE) was found to be downregulated by warming as a result of a stronger sensitivity to warming in respiration (15.6%) than in photosynthesis (6.2%). Vegetation usually responded to warming by investing more C to the belowground, as belowground biomass increased much more (30.1%) than aboveground biomass (2.9%). Warming had a minor effect on microbial biomass. Warming increased soil ammonium and nitrate concentrations. What's more, a synthesis of 70 observations from 11 herbs and 9 shrubs revealed a 2.5% decline of N in green leaves. Compared with herbs, shrubs had a stronger response to respiration and had a decline in green leaf N to a greater extent. Not only in dry condition did green leaf N decline with warming but also in wet conditions. Warming in nongrowing seasons would negatively affect soil water, C uptake, and biomass production during growing seasons. Permafrost C loss and vegetation N decline may increase with warming levels and timing. Overall, these findings suggest that besides a positive C cycling-climate feedback, there will be a negative feedback between permafrost nutrient cycling and climate warming.
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Affiliation(s)
- Wenlong Gao
- National‐Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South ChinaGuangdong Key Laboratory of Integrated Agro‐environmental Pollution Control and ManagementInstitute of Eco‐environmental and Soil SciencesGuangdong Academy of SciencesGuangzhouChina
- Hainan Key Laboratory of Tropical Eco‐Circular AgricultureEnvironment and Plant Protection InstituteChinese Academy of Tropical Agricultural SciencesHaikouChina
- Hainan Danzhou Tropical Agro‐ecosystem National Observation and Research StationDanzhouChina
| | - Weimin Sun
- National‐Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South ChinaGuangdong Key Laboratory of Integrated Agro‐environmental Pollution Control and ManagementInstitute of Eco‐environmental and Soil SciencesGuangdong Academy of SciencesGuangzhouChina
- School of EnvironmentHenan Normal UniversityXinxiangChina
- Key Laboratory of Yellow River and Huai River Water Environment and Pollution ControlMinistry of EducationBeijingChina
| | - Xingliang Xu
- Key Laboratory of Ecosystem Network Observation and ModelingInstitute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijingChina
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Gao T, Kang S, Chen R, Wang X, Yang J, Luo X, Wang X, Paudyal R, Han C, He R, Sillanpää M, Zhang Y. Characteristics of dissolved organic carbon and nitrogen in precipitation in the northern Tibetan Plateau. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 776:145911. [PMID: 33647655 DOI: 10.1016/j.scitotenv.2021.145911] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Revised: 02/04/2021] [Accepted: 02/12/2021] [Indexed: 06/12/2023]
Abstract
Dissolved organic carbon (DOC) and nitrogen (N) play essential roles in global C and N cycles. To address the possible role of DOC and N in precipitation and enrich the related global database, the characteristics of DOC and N in precipitation were investigated in a typical remote permafrost region (upper Heihe River Basin) of the northern Tibetan Plateau (TP) from February 2019 to March 2020. The results demonstrated that the average DOC and total dissolved N (TDN) concentrations in the precipitation were 1.41 ± 1.09 μg mL-1 and 0.84 ± 0.48 μg mL-1, respectively, with relatively lower concentrations in the summer. The annual DOC and TDN fluxes were estimated to be 6.42 kg ha-1 yr-1 and 3.39 kg ha-1 yr-1, respectively, indicating that precipitation was a significant factor in C and N deposition. The light-absorbing properties of precipitation DOC from the SUVA254 and spectral slope revealed that precipitation DOC containing more aromatic components and lower molecular weights mostly was present during the summer; the mass cross-section (at the wavelength of 365 nm) ranged 0.26-1.84 m2 g-1, suggesting the potential impact of DOC on climatic forcing in the area. The principal component analysis combined with air mass backward trajectories indicated that the air masses from west Siberia, Central Asia, and northwestern China most significantly influenced the precipitation C and N in the study area. The WRF-Chem simulations and aerosol vertical distributions further illustrated the air mass transport pathways, demonstrating that dust and anthropogenic emissions could be transported over the studied area by westerlies and monsoonal winds. In the study basin, the precipitation deposition of DOC and N contributed largely to the riverine DOC and N exportation during the summer and had potential ecological effects. These results highlight the importance of DOC and N deposition from precipitation in the northern TP.
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Affiliation(s)
- Tanguang Gao
- Key Laboratory of Western China's Environmental Systems (Ministry of Education), College of Earth and Environmental Sciences, Lanzhou University, Lanzhou 730000, China
| | - Shichang Kang
- CAS Centre for Excellence in Tibetan Plateau Earth Sciences, Chinese Academy of Sciences, Beijing 100101, China; State Key Laboratory of Cryosphere Sciences, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China
| | - Rensheng Chen
- State Key Laboratory of Cryosphere Sciences, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China
| | - Xiaoming Wang
- State Key Laboratory of Cryosphere Sciences, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China
| | - Junhua Yang
- CAS Centre for Excellence in Tibetan Plateau Earth Sciences, Chinese Academy of Sciences, Beijing 100101, China
| | - Xi Luo
- State Key Laboratory of Cryosphere Sciences, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xiaoxiang Wang
- State Key Laboratory of Cryosphere Sciences, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China
| | - Rukumesh Paudyal
- State Key Laboratory of Cryosphere Sciences, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China
| | - Chuntan Han
- State Key Laboratory of Cryosphere Sciences, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China
| | - Ruixia He
- State Key Laboratory of Frozen Soil Engineering, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China
| | - Mika Sillanpää
- Institute of Research and Development, and Faculty of Environment and Chemical Engineering, Duy Tan University, Da Nang 550000, Viet Nam; School of Civil Engineering and Surveying, Faculty of Health, Engineering and Sciences, University of Southern Queensland, West Street, Toowoomba, 4350, QLD, Australia
| | - Yulan Zhang
- CAS Centre for Excellence in Tibetan Plateau Earth Sciences, Chinese Academy of Sciences, Beijing 100101, China; State Key Laboratory of Cryosphere Sciences, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China.
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30
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Yang L, Zhao H, Zuo Z, Li X, Yu D, Wang Z. Generality and Shifts in Leaf Trait Relationships Between Alpine Aquatic and Terrestrial Herbaceous Plants on the Tibetan Plateau. Front Ecol Evol 2021. [DOI: 10.3389/fevo.2021.706237] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Plant traits mirror both evolutionary and environmental filtering process with universal trait-trait relationships across plant groups. However, plants also develop unique traits precisely to different habitats, inducing deviations of the trait coupling relations. In this study, we aimed to compare the differences in leaf traits and examine the generality and shifts of trait-trait relationships between alpine aquatic and terrestrial herbaceous plants on the Tibetan Plateau, to explore the precise adaptive strategies of aquatic and terrestrial plants for its habitats. We measured mass-based and area-based leaf N and P concentrations, N:P ratios and specific leaf area (SLA) of aquatic and terrestrial herbaceous plants. Standardized major axis analysis were applied to build the correlations for every trait pairs of each plant group, and then to compare the differences in the trait-trait correlations among different plant groups. Leaf Nmass and Pmass of two groups of aquatic plants (emergent and submerged plants) were higher, but N:P ratios were lower than those of two groups of terrestrial plants (sedges and grasses). Submerged plants had extremely high SLA, while grasses had the lowest SLA. Nmass positively correlated with Pmass in three out of four plant groups. The two terrestrial plant groups had positive Nmass-SLA relationships but these two traits coupled weakly in aquatic plants. Pmass showed positive relationships to SLA in three out of four plant groups. Significant shifts of trait-trait relationships between aquatic and terrestrial plants were observed. In general, aquatic plants, especially submerged plants, are characterized by higher SLA, greater leaf nutrientmass than terrestrial plants, tend to pursue fast-return investment strategies, and represent the acquisitive end of leaf economics spectrum. The deviations of trait-trait relationships between different plant groups reveal the precise adaptions of submerged plants to the unique aquatic habitats.
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Abbott BW, Rocha AV, Shogren A, Zarnetske JP, Iannucci F, Bowden WB, Bratsman SP, Patch L, Watts R, Fulweber R, Frei RJ, Huebner AM, Ludwig SM, Carling GT, O'Donnell JA. Tundra wildfire triggers sustained lateral nutrient loss in Alaskan Arctic. GLOBAL CHANGE BIOLOGY 2021; 27:1408-1430. [PMID: 33394532 DOI: 10.1111/gcb.15507] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Accepted: 12/13/2020] [Indexed: 06/12/2023]
Abstract
Climate change is creating widespread ecosystem disturbance across the permafrost zone, including a rapid increase in the extent and severity of tundra wildfire. The expansion of this previously rare disturbance has unknown consequences for lateral nutrient flux from terrestrial to aquatic environments. Lateral loss of nutrients could reduce carbon uptake and slow recovery of already nutrient-limited tundra ecosystems. To investigate the effects of tundra wildfire on lateral nutrient export, we analyzed water chemistry in and around the 10-year-old Anaktuvuk River fire scar in northern Alaska. We collected water samples from 21 burned and 21 unburned watersheds during snowmelt, at peak growing season, and after plant senescence in 2017 and 2018. After a decade of ecosystem recovery, aboveground biomass had recovered in burned watersheds, but overall carbon and nitrogen remained ~20% lower, and the active layer remained ~10% deeper. Despite lower organic matter stocks, dissolved organic nutrients were substantially elevated in burned watersheds, with higher flow-weighted concentrations of organic carbon (25% higher), organic nitrogen (59% higher), organic phosphorus (65% higher), and organic sulfur (47% higher). Geochemical proxies indicated greater interaction with mineral soils in watersheds with surface subsidence, but optical analysis and isotopes suggested that recent plant growth, not mineral soil, was the main source of organic nutrients in burned watersheds. Burned and unburned watersheds had similar δ15 N-NO3 - , indicating that exported nitrogen was of preburn origin (i.e., not recently fixed). Lateral nitrogen flux from burned watersheds was 2- to 10-fold higher than rates of background nitrogen fixation and atmospheric deposition estimated in this area. These findings indicate that wildfire in Arctic tundra can destabilize nitrogen, phosphorus, and sulfur previously stored in permafrost via plant uptake and leaching. This plant-mediated nutrient loss could exacerbate terrestrial nutrient limitation after disturbance or serve as an important nutrient release mechanism during succession.
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Affiliation(s)
- Benjamin W Abbott
- Department of Plant and Wildlife Sciences, Brigham Young University, Provo, UT, USA
| | - Adrian V Rocha
- Department of Biological Sciences & the Environmental Change Initiative, University of Notre Dame, Notre Dame, IN, USA
| | - Arial Shogren
- Department of Earth and Environmental Sciences, Michigan State University, East Lansing, MI, USA
| | - Jay P Zarnetske
- Department of Earth and Environmental Sciences, Michigan State University, East Lansing, MI, USA
| | - Frances Iannucci
- Rubenstein School of Environment and Natural Resources, University of Vermont, Burlington, VT, USA
- Department of Biology and Wildlife, University of Alaska Fairbanks, Fairbanks, AK, USA
| | - William B Bowden
- Rubenstein School of Environment and Natural Resources, University of Vermont, Burlington, VT, USA
| | - Samuel P Bratsman
- Department of Plant and Wildlife Sciences, Brigham Young University, Provo, UT, USA
| | - Leika Patch
- Department of Plant and Wildlife Sciences, Brigham Young University, Provo, UT, USA
| | - Rachel Watts
- Department of Plant and Wildlife Sciences, Brigham Young University, Provo, UT, USA
| | - Randy Fulweber
- Toolik GIS, University of Alaska Fairbanks, Fairbanks, AK, USA
| | - Rebecca J Frei
- Department of Plant and Wildlife Sciences, Brigham Young University, Provo, UT, USA
- Department of Renewable Resources, University of Alberta, Edmonton, AB, Canada
| | - Amanda M Huebner
- Department of Plant and Wildlife Sciences, Brigham Young University, Provo, UT, USA
| | - Sarah M Ludwig
- Department of Earth and Environmental Science, Columbia University, NY, NY, USA
| | - Gregory T Carling
- Department of Geological Sciences, Brigham Young University, Provo, UT, USA
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32
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Liu Y, Geng X, Wei D, Dai D. Divergence in ecosystem carbon fluxes and soil nitrogen characteristics across alpine steppe, alpine meadow and alpine swamp ecosystems in a biome transition zone. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 748:142453. [PMID: 33113693 DOI: 10.1016/j.scitotenv.2020.142453] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 09/13/2020] [Accepted: 09/13/2020] [Indexed: 06/11/2023]
Abstract
Alpine ecosystem carbon cycling is sensitive to climate change, particularly in the transition zones between biomes. Soil nitrogen conditions, including the ammonium to nitrate (NH4+/NO3-) ratio, regulate ecosystem carbon uptake by coupling carbon‑nitrogen cycle. The largest alpine pasture on Earth is distributed on the Tibetan Plateau, where alpine biome transition zones are also widely distributed. However, it is largely unknown how the soil NH4+/NO3- ratio and net ecosystem CO2 exchange vary among vegetation types in the alpine biome transition zones due to a lack of in situ field observations. Here, we investigated soil NH4+/NO3- ratio and ecosystem carbon fluxes across alpine steppe, alpine meadow and alpine swamp ecosystems in a biome transition zone on the central Tibetan Plateau. The results showed that soil NH4+/NO3- ratio was lowest in the alpine steppe (driest environment), which had the highest soil pH, and highest in the alpine swamp (wettest environment), which had the lowest soil pH. We proposed a theoretical framework describing how soil moisture regulates soil NH4+/NO3- ratio by altering both the denitrification process and soil pH. We further found that the growing season average net ecosystem CO2 exchange for the alpine steppe, alpine meadow and alpine swamp was -1.46, -1.90 and -5.43 μmol m-2 s-1, respectively. This divergence in net ecosystem CO2 exchange across the three grasslands is primarily explained by divergence in gross ecosystem photosynthesis, rather than ecosystem respiration. The air temperature sensitivity of ecosystem respiration (Q10) for the alpine steppe, alpine meadow and alpine swamp was 1.73 ± 0.05, 1.44 ± 0.03 and 2.43 ± 0.45, respectively. Our study highlights large differences in both soil nutrient and ecosystem carbon uptake across different vegetation types in an alpine biome transition zone. More in situ investigations in various biome transition zones are urgently needed to quantitatively understand the spatial pattern of alpine ecosystem carbon‑nitrogen cycling processes.
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Affiliation(s)
- Yongwen Liu
- Key Laboratory of Alpine Ecology, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101, China; CAS Center for Excellence in Tibetan Plateau Earth Sciences, Chinese Academy of Sciences, Beijing 100101, China.
| | - Xiaodong Geng
- School of Resources and Environment, Anqing Normal University, Anqing 246133, China
| | - Da Wei
- Key Laboratory of Mountain Surface Processes and Ecological Regulation, Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu 610041, China
| | - Dongxue Dai
- College of Biology and Food Science, Hebei Normal University for Nationalities, Chengde 067000, China
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