Siwa Oasis,one of Egypts most remote settlements,is also a popular tourist destination thanks to the beautiful salt pools with water that people can float in.Salt is both a blessing and a curse in Siwa.Years ago,peopl...Siwa Oasis,one of Egypts most remote settlements,is also a popular tourist destination thanks to the beautiful salt pools with water that people can float in.Salt is both a blessing and a curse in Siwa.Years ago,people started realizing that there was money to be made in the salt trade,and salt mining operations created the salt lakes that the oasis is now famous for.展开更多
Dunhuang,located in the northwestern part of China,is a town that feels like it's carved out of the pages of a history book.Nestled at the edge of the Gobi Desert in China's Gansu Province,this ancient oasis c...Dunhuang,located in the northwestern part of China,is a town that feels like it's carved out of the pages of a history book.Nestled at the edge of the Gobi Desert in China's Gansu Province,this ancient oasis city has been a crossroads of cultures,religions,and trade for over 2,000 years.展开更多
The diversity and discontinuity of plant communities in the oasis–desert ecotone are largely shaped by variations in groundwater depth,yet the relationships between spatial distribution patterns and ecological niches...The diversity and discontinuity of plant communities in the oasis–desert ecotone are largely shaped by variations in groundwater depth,yet the relationships between spatial distribution patterns and ecological niches at a regional scale remain insufficiently understood.This study examined the oasis–desert ecotone in Qira County located in the Tarim Basin of China to investigate the spatial distribution of plant communities and groundwater depth as well as their relationships using an integrated approach that combined remote sensing techniques,field monitoring,and numerical modeling.The results showed that vegetation distribution exhibits marked spatial heterogeneity,with coverage ranked as follows:Tamarix ramosissima>Phragmites australis>Populus euphratica>Alhagi sparsifolia.Numerical simulations indicated that groundwater depths range from 2.00 to 65.00 m below the surface,with the system currently in equilibrium,sustaining an average annual recharge of 1.06×10^(8) m^(3) and an average annual discharge of 1.01×10^(8) m^(3).Groundwater depth strongly influences vegetation composition and structure:Phragmites australis dominates at average groundwater depth of 5.83 m,followed by Populus euphratica at average groundwater depth of 7.05 m.As groundwater depth increases,the community is initially predominated by Tamarix ramosissima(average groundwater depth of 8.35 m),then becomes a mixture of Tamarix ramosissima,Populus euphratica,and Karelinia caspia(average groundwater depth of 10.50 m),and finally transitions to Alhagi sparsifolia(average groundwater depth of 14.30 m).These findings highlight groundwater-dependent ecological thresholds that govern plant community composition and provide a scientific basis for biodiversity conservation,ecosystem stability,and vegetation restoration in the arid oasis–desert ecotone.展开更多
Carbon fluxes are essential indicators assessing vegetation carbon cycle functions.However,the extent and mechanisms by which climate change and human activities influence the spatiotemporal dynamics of carbon fluxes ...Carbon fluxes are essential indicators assessing vegetation carbon cycle functions.However,the extent and mechanisms by which climate change and human activities influence the spatiotemporal dynamics of carbon fluxes in arid oasis and non-oasis area remains unclear.Here,we assessed and predicted the future effects of climate change and human activities on carbon fluxes in the Hexi Corridor.The results showed that the annual average gross primary productivity(GPP),net ecosystem productivity(NEP),and ecosystem respiration(Reco)in the Hexi Corridor oasis increased by 263.91 g C·m^(-2)·yr^(-1),118.45 g C·m^(-2)·yr^(-1)and 122.46 g C·m^(-2)·yr^(-1),respectively,due to the expansion of the oasis area by 3424.84 km^(2) caused by human activities from 2000 to 2022.Both oasis and non-oasis arid ecosystems in the Hexi Corridor acted as carbon sinks.Compared to the non-oasis area,the carbon fluxes contributions of oasis area increased,ranging from 10.21%to 13.99%for GPP,8.50%to11.68%for NEP,and 13.34%to 17.13%for Reco.The contribution of the carbon flux from the oasis expansion area to the total carbon flux change in the Hexi Corridor was 30.96%(7.09 Tg C yr^(-1))for GPP,29.57%(3.39 Tg C yr^(-1))for NEP and 32.40%(3.58 Tg C yr^(-1))for Reco.The changes in carbon fluxes in the oasis area were mainly attributed to human activities(oasis expansion)and temperature,whereas non-oasis area was mainly due to climate factors.Moreover,the future increasing trends were observed for GPP(64.99%),NEP(66.29%)and Reco(82.08%)in the Hexi Corridor.This study provides new insights into the regulatory mechanisms of carbon cycle in the arid oasis and non-oasis area.展开更多
Biological soil crusts(BSCs)play crucial roles in improving soil fertility and promoting plants settlement and reproduction in arid areas.However,the specific effects of BSCs on growth status and nutrient accumulation...Biological soil crusts(BSCs)play crucial roles in improving soil fertility and promoting plants settlement and reproduction in arid areas.However,the specific effects of BSCs on growth status and nutrient accumulation of plants are still unclear in different arid areas.This study analyzed the effects of three different BSCs treatments(without crust(WC),intact crust(IC),and broken crust(BC))on the growth,inorganic nutrient absorption,and organic solute synthesis of three typical desert plants(Grubovia dasyphylla(Fisch.&C.A.Mey.)Freitag&G.Kadereit,Nitraria tangutorum Bobrov,and Caragana koraiensis Kom.)in the Minqin desert-oasis ecotone of Northwest China.Results showed that the effects of three BSCs treatments on seed emergence and survival of three plants varied with seed types.The IC treatment significantly hindered the emergence and survival of seeds,while the BC treatment was more conducive to seed emergence and survival of plants.BSCs significantly promoted the growth of three plants,but their effects on plant growth varied at different stages of the growth.Briefly,the growth of G.dasyphylla was affected by BSCs in early stage,but the effects on the growth of G.dasyphylla significantly weakened in the middle and late stages.However,the growth of N.tangutorum and C.koraiensis only showed differences at the middle and late stages,with a significant enhancement in growth.Analysis of variance showed that BSCs,plant species,growth period,and their interactions had significant effects on the biomass and root:shoot ratio of three plants.BSC significantly affected the nutrients absorption and organic solute synthesis in plants.Specifically,BSCs significantly promoted nitrogen(N)absorption in plants and increased plant adaptability in N poor desert ecosystems,but had no significant effects on phosphorus(P)absorption.The effects of BSCs on inorganic nutrient absorption and organic solute synthesis in plants varied significantly among different plant species.The results suggest that BSCs have significant effects on the growth and nutrient accumulation of desert plants,which will provide theoretical basis for exploring the effects of BSCs on desert plant diversity,biodiversity conservation,and ecosystem management measures in arid and semi-arid areas.展开更多
建立了超高效液相色谱串联质谱法同时测定56种动物源性兽药残留物的分析方法。以乙腈-0.5%乙酸水溶液(85:15,V/V)为提取溶剂,采用固相萃取柱(Oasis PRi ME HLB)进行样品净化,通过UPLC-MS/MS分析测定,基质曲线外标法定量。方法定量限为1....建立了超高效液相色谱串联质谱法同时测定56种动物源性兽药残留物的分析方法。以乙腈-0.5%乙酸水溶液(85:15,V/V)为提取溶剂,采用固相萃取柱(Oasis PRi ME HLB)进行样品净化,通过UPLC-MS/MS分析测定,基质曲线外标法定量。方法定量限为1.0μg/kg(喹诺酮类)、1.5μg/kg(糖皮质类)、10μg/kg(磺胺类)、1.0μg/kg(β-受体激动剂类)。56种兽药残留物在牛肉、猪肉、鸡肉和奶等基质样品中回收率范围为63.2%~101.5%,基质标准工作曲线线性相关系数大于0.937,精密度RSD<15%(n=3)。方法适用于动物源性食品中兽药残留物的分析。展开更多
酚类化合物是环境水中主要污染物之一,水资源污染问题严重影响了人们的身体健康。研究水中酚类化合物的测定方法有着重要意义,因此本实验建立了高效液相色谱法测定水体中9种酚类化合物分析方法。本方法相比传统其它检测方法选取Oasis PR...酚类化合物是环境水中主要污染物之一,水资源污染问题严重影响了人们的身体健康。研究水中酚类化合物的测定方法有着重要意义,因此本实验建立了高效液相色谱法测定水体中9种酚类化合物分析方法。本方法相比传统其它检测方法选取Oasis PRiME HLB固相萃取柱对水样净化富集,甲醇洗脱,定容过滤后通过高效液相色谱分析测定。外标法定量,9种酚类化合物苯酚、对硝基酚、4-氯间酚、邻氯酚、邻硝基酚、2,4-二甲酚、2,4-二氯酚、2,4,6-三氯酚和五氯酚的检出限为0.005~0.01μg/mL,工作曲线线性相关系数0.9992~0.9998,样品回收率范围86.5~92.4%,相对标准偏差RSD为0.8~2.2%,本方法分离效能高、检测灵敏,选择性强,适用于地表水中酚类化合物的测定。展开更多
Guazhou County of Gansu Province is a typical ecological fragile area lying in the transition area of desert and oasis.The development of its agricultural economy is highly dependent on natural resources and environme...Guazhou County of Gansu Province is a typical ecological fragile area lying in the transition area of desert and oasis.The development of its agricultural economy is highly dependent on natural resources and environment.Contradiction of resources characterized agriculture and the fragile ecological environment has become one of the main barriers to log the impact of local agriculture to achieve sustainable development.Aiming at fragile ecological environment and limiting factors of agricultural sustainable development,thoughts and countermeasures of realizing agricultural sustainable development have been proposed.展开更多
[Objective] This study aimed to evaluate the environmental effects coming from land changes in Hotan oasis during 1980-2010. [Method] Based on the Driving Force-State-Response model, expert weight method and entropy m...[Objective] This study aimed to evaluate the environmental effects coming from land changes in Hotan oasis during 1980-2010. [Method] Based on the Driving Force-State-Response model, expert weight method and entropy method were used to determine weight, and then the composite indexes of environmental effects （CIE for short） were calculated. [Result] During the period from 1980 to 2010, CIE had presented a rising trend whether expert weight method or entropy method in the study area, while the CIE presents downtrend basically in lower reaches. [Conclu- sion] It was the arable land expansion in middle reaches that led to serious land degradation in lower reaches, and may endanger ecosystem safety in Hotan River green corridor. Therefore, it is suggested that the agricultural land use should be restructured, such as reducing the sown areas of some crops with large amount of water consumption. Meanwhile, the effective measures should be taken to distribute water resources and utilize them reasonably. In addition, the oasis-desert ecotone, as well as the groundwater resources, should be also protected.展开更多
[Objective] The study aimed to assess the ecosystem services value in Hotan Oasis, Xingjiang. [Method] The visual interpretation method was adopted to process TM/ETM＋ images based on field investigation in Hotan Oasi...[Objective] The study aimed to assess the ecosystem services value in Hotan Oasis, Xingjiang. [Method] The visual interpretation method was adopted to process TM/ETM＋ images based on field investigation in Hotan Oasis. These inter- pretation data, along with two periods of land use data, were reclassified to farm- land, forest, grassland and so on. Then, the ecosystem services value was calculat- ed and analyzed. [Result] Analysis indicated that the ecosystem services value had been increased by 30.44x108 Yuan （16.51%） in the study area during 1980-2010, which can be explained by the increase of glacier and snowfield distributed in the south mountain with the increase of annual precipitation. At the same time, the con- tribution rate of grassland to ecosystem services value had been decreased as a result of degradation of grassland and occupation from farmland. For the whole basin, the increase of ecosystem services value came from the upper reaches, while the ecosystem services value had been reduced in the middle and lower reaches. In the middle reaches, the reduction came mainly from wetland （-1.83x10s Yuan）, waters （-1.68x10s Yuan）, forest （-0.86x108 Yuan） and grassland （-0.80x108 Yuan）. But in the lower reaches, the ecosystem services values of waters, grassland and forest were -0.61 x108 Yuan, -0.24x108 Yuan, and -0.07x10s Yuan, respectively. [Conclusion] If some effective policies, such as the implementation of returning farm- land to forest and ceasing from farming to grazing, would be taken, the ecosystem degradation can be constrained and reversed in the northwest arid region.展开更多
文摘Siwa Oasis,one of Egypts most remote settlements,is also a popular tourist destination thanks to the beautiful salt pools with water that people can float in.Salt is both a blessing and a curse in Siwa.Years ago,people started realizing that there was money to be made in the salt trade,and salt mining operations created the salt lakes that the oasis is now famous for.
文摘Dunhuang,located in the northwestern part of China,is a town that feels like it's carved out of the pages of a history book.Nestled at the edge of the Gobi Desert in China's Gansu Province,this ancient oasis city has been a crossroads of cultures,religions,and trade for over 2,000 years.
基金financially supported by the Tianchi Talents Program of Xinjiang Uygur Autonomous Region(E5358525,2025–2026)the Major Science and Technology Special Project of Xinjiang Uygur Autonomous Region(2024A03009-4)+4 种基金the Third Xinjiang Scientific Expedition Program(2022xjkk010402)the National Key Research and Development Program of China(2022FY202305-06)the Tianshan Talents Program of Xinjiang Uygur Autonomous Region(2022TSYCJU0002)the Outstanding Member of the Youth Innovation Promotion Association of the Chinese Academy of Sciences(20192024–2026).
文摘The diversity and discontinuity of plant communities in the oasis–desert ecotone are largely shaped by variations in groundwater depth,yet the relationships between spatial distribution patterns and ecological niches at a regional scale remain insufficiently understood.This study examined the oasis–desert ecotone in Qira County located in the Tarim Basin of China to investigate the spatial distribution of plant communities and groundwater depth as well as their relationships using an integrated approach that combined remote sensing techniques,field monitoring,and numerical modeling.The results showed that vegetation distribution exhibits marked spatial heterogeneity,with coverage ranked as follows:Tamarix ramosissima>Phragmites australis>Populus euphratica>Alhagi sparsifolia.Numerical simulations indicated that groundwater depths range from 2.00 to 65.00 m below the surface,with the system currently in equilibrium,sustaining an average annual recharge of 1.06×10^(8) m^(3) and an average annual discharge of 1.01×10^(8) m^(3).Groundwater depth strongly influences vegetation composition and structure:Phragmites australis dominates at average groundwater depth of 5.83 m,followed by Populus euphratica at average groundwater depth of 7.05 m.As groundwater depth increases,the community is initially predominated by Tamarix ramosissima(average groundwater depth of 8.35 m),then becomes a mixture of Tamarix ramosissima,Populus euphratica,and Karelinia caspia(average groundwater depth of 10.50 m),and finally transitions to Alhagi sparsifolia(average groundwater depth of 14.30 m).These findings highlight groundwater-dependent ecological thresholds that govern plant community composition and provide a scientific basis for biodiversity conservation,ecosystem stability,and vegetation restoration in the arid oasis–desert ecotone.
基金The Foundation for Distinguished Young Scholars of Gansu Province,No.22JR5RA046Key Research Program of Gansu Province,No.23ZDKA0004+2 种基金The Joint Funds of the National Natural Science Foundation of China,No.U22A202690Interdisciplinary Youth Team Project from the Key Laboratory of Cryospheric Science and Frozen Soil Engineering,No.CSFSE-ZQ-2408The Youth Innovation Promotion Association CAS to X.W.,No.2020422。
文摘Carbon fluxes are essential indicators assessing vegetation carbon cycle functions.However,the extent and mechanisms by which climate change and human activities influence the spatiotemporal dynamics of carbon fluxes in arid oasis and non-oasis area remains unclear.Here,we assessed and predicted the future effects of climate change and human activities on carbon fluxes in the Hexi Corridor.The results showed that the annual average gross primary productivity(GPP),net ecosystem productivity(NEP),and ecosystem respiration(Reco)in the Hexi Corridor oasis increased by 263.91 g C·m^(-2)·yr^(-1),118.45 g C·m^(-2)·yr^(-1)and 122.46 g C·m^(-2)·yr^(-1),respectively,due to the expansion of the oasis area by 3424.84 km^(2) caused by human activities from 2000 to 2022.Both oasis and non-oasis arid ecosystems in the Hexi Corridor acted as carbon sinks.Compared to the non-oasis area,the carbon fluxes contributions of oasis area increased,ranging from 10.21%to 13.99%for GPP,8.50%to11.68%for NEP,and 13.34%to 17.13%for Reco.The contribution of the carbon flux from the oasis expansion area to the total carbon flux change in the Hexi Corridor was 30.96%(7.09 Tg C yr^(-1))for GPP,29.57%(3.39 Tg C yr^(-1))for NEP and 32.40%(3.58 Tg C yr^(-1))for Reco.The changes in carbon fluxes in the oasis area were mainly attributed to human activities(oasis expansion)and temperature,whereas non-oasis area was mainly due to climate factors.Moreover,the future increasing trends were observed for GPP(64.99%),NEP(66.29%)and Reco(82.08%)in the Hexi Corridor.This study provides new insights into the regulatory mechanisms of carbon cycle in the arid oasis and non-oasis area.
基金supported by the Natural Science Foundation of Gansu Province,China(24JRRA733,23JRRA589)the National Natural Science Foundation of China(42377470,42207539)the Light of Western Light Program of Talent Cultivation of Chinese Academy of Sciences(22JR9KA028).
文摘Biological soil crusts(BSCs)play crucial roles in improving soil fertility and promoting plants settlement and reproduction in arid areas.However,the specific effects of BSCs on growth status and nutrient accumulation of plants are still unclear in different arid areas.This study analyzed the effects of three different BSCs treatments(without crust(WC),intact crust(IC),and broken crust(BC))on the growth,inorganic nutrient absorption,and organic solute synthesis of three typical desert plants(Grubovia dasyphylla(Fisch.&C.A.Mey.)Freitag&G.Kadereit,Nitraria tangutorum Bobrov,and Caragana koraiensis Kom.)in the Minqin desert-oasis ecotone of Northwest China.Results showed that the effects of three BSCs treatments on seed emergence and survival of three plants varied with seed types.The IC treatment significantly hindered the emergence and survival of seeds,while the BC treatment was more conducive to seed emergence and survival of plants.BSCs significantly promoted the growth of three plants,but their effects on plant growth varied at different stages of the growth.Briefly,the growth of G.dasyphylla was affected by BSCs in early stage,but the effects on the growth of G.dasyphylla significantly weakened in the middle and late stages.However,the growth of N.tangutorum and C.koraiensis only showed differences at the middle and late stages,with a significant enhancement in growth.Analysis of variance showed that BSCs,plant species,growth period,and their interactions had significant effects on the biomass and root:shoot ratio of three plants.BSC significantly affected the nutrients absorption and organic solute synthesis in plants.Specifically,BSCs significantly promoted nitrogen(N)absorption in plants and increased plant adaptability in N poor desert ecosystems,but had no significant effects on phosphorus(P)absorption.The effects of BSCs on inorganic nutrient absorption and organic solute synthesis in plants varied significantly among different plant species.The results suggest that BSCs have significant effects on the growth and nutrient accumulation of desert plants,which will provide theoretical basis for exploring the effects of BSCs on desert plant diversity,biodiversity conservation,and ecosystem management measures in arid and semi-arid areas.
文摘建立了超高效液相色谱串联质谱法同时测定56种动物源性兽药残留物的分析方法。以乙腈-0.5%乙酸水溶液(85:15,V/V)为提取溶剂,采用固相萃取柱(Oasis PRi ME HLB)进行样品净化,通过UPLC-MS/MS分析测定,基质曲线外标法定量。方法定量限为1.0μg/kg(喹诺酮类)、1.5μg/kg(糖皮质类)、10μg/kg(磺胺类)、1.0μg/kg(β-受体激动剂类)。56种兽药残留物在牛肉、猪肉、鸡肉和奶等基质样品中回收率范围为63.2%~101.5%,基质标准工作曲线线性相关系数大于0.937,精密度RSD<15%(n=3)。方法适用于动物源性食品中兽药残留物的分析。
文摘酚类化合物是环境水中主要污染物之一,水资源污染问题严重影响了人们的身体健康。研究水中酚类化合物的测定方法有着重要意义,因此本实验建立了高效液相色谱法测定水体中9种酚类化合物分析方法。本方法相比传统其它检测方法选取Oasis PRiME HLB固相萃取柱对水样净化富集,甲醇洗脱,定容过滤后通过高效液相色谱分析测定。外标法定量,9种酚类化合物苯酚、对硝基酚、4-氯间酚、邻氯酚、邻硝基酚、2,4-二甲酚、2,4-二氯酚、2,4,6-三氯酚和五氯酚的检出限为0.005~0.01μg/mL,工作曲线线性相关系数0.9992~0.9998,样品回收率范围86.5~92.4%,相对标准偏差RSD为0.8~2.2%,本方法分离效能高、检测灵敏,选择性强,适用于地表水中酚类化合物的测定。
基金Supported by Central Public-interest Scientific Institution Basal Research Fund of China(BRF090202)~~
文摘Guazhou County of Gansu Province is a typical ecological fragile area lying in the transition area of desert and oasis.The development of its agricultural economy is highly dependent on natural resources and environment.Contradiction of resources characterized agriculture and the fragile ecological environment has become one of the main barriers to log the impact of local agriculture to achieve sustainable development.Aiming at fragile ecological environment and limiting factors of agricultural sustainable development,thoughts and countermeasures of realizing agricultural sustainable development have been proposed.
基金Supported by Major State Basic Research Development Program of China(973 Program,2010CB955905)Fund from Hebei Normal University for Nationalities for the Research of the Temporal Evolution in Hotan Oasis with Climate Change(201304)~~
文摘[Objective] This study aimed to evaluate the environmental effects coming from land changes in Hotan oasis during 1980-2010. [Method] Based on the Driving Force-State-Response model, expert weight method and entropy method were used to determine weight, and then the composite indexes of environmental effects （CIE for short） were calculated. [Result] During the period from 1980 to 2010, CIE had presented a rising trend whether expert weight method or entropy method in the study area, while the CIE presents downtrend basically in lower reaches. [Conclu- sion] It was the arable land expansion in middle reaches that led to serious land degradation in lower reaches, and may endanger ecosystem safety in Hotan River green corridor. Therefore, it is suggested that the agricultural land use should be restructured, such as reducing the sown areas of some crops with large amount of water consumption. Meanwhile, the effective measures should be taken to distribute water resources and utilize them reasonably. In addition, the oasis-desert ecotone, as well as the groundwater resources, should be also protected.
基金Supported by the National Basic Research Program of China (973 Program, 2010CB955905)~~
文摘[Objective] The study aimed to assess the ecosystem services value in Hotan Oasis, Xingjiang. [Method] The visual interpretation method was adopted to process TM/ETM＋ images based on field investigation in Hotan Oasis. These inter- pretation data, along with two periods of land use data, were reclassified to farm- land, forest, grassland and so on. Then, the ecosystem services value was calculat- ed and analyzed. [Result] Analysis indicated that the ecosystem services value had been increased by 30.44x108 Yuan （16.51%） in the study area during 1980-2010, which can be explained by the increase of glacier and snowfield distributed in the south mountain with the increase of annual precipitation. At the same time, the con- tribution rate of grassland to ecosystem services value had been decreased as a result of degradation of grassland and occupation from farmland. For the whole basin, the increase of ecosystem services value came from the upper reaches, while the ecosystem services value had been reduced in the middle and lower reaches. In the middle reaches, the reduction came mainly from wetland （-1.83x10s Yuan）, waters （-1.68x10s Yuan）, forest （-0.86x108 Yuan） and grassland （-0.80x108 Yuan）. But in the lower reaches, the ecosystem services values of waters, grassland and forest were -0.61 x108 Yuan, -0.24x108 Yuan, and -0.07x10s Yuan, respectively. [Conclusion] If some effective policies, such as the implementation of returning farm- land to forest and ceasing from farming to grazing, would be taken, the ecosystem degradation can be constrained and reversed in the northwest arid region.
