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Lake regime shift from submerged macrophyte to phytoplankton affected phosphorus speciation in sediment and eutrophic state in Caohai Lake,Guizhou,China

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Journal of Oceanology and Limnology 2023年第6期41卷 2262-2275页

作者： Jixing DONG Yanmin GUO Pinhua XIA Yuanbin TIAN Feifei ZHENG Anyan LI Tao LIN Ruiwen LI Guizhou Province Key Laboratory for Information system of mountainous Areas and Protection of Ecological environment Guizhou Normal UniversityGuiyang 550001China Yangtze River basin Ecological environment Monitoring and Scientific Research center Yangtze River Basin Ecological Environment Supervision and Administration BureauMinistry of Ecological EnvironmentWuhan 430010China

To understand the effect of regime shift in Caohai Lake in Yunnan-Guizhou Plateau,SW China from submerged macrophyte dominance to phytoplankton dominance on the specification and distribution of phosphorus and on ecological and environmental states,changes in phosphorus specification in the sediments and water were *** form,composition,and distribution of phosphorus in sediment were sampled in July 2020(before regime shift)and July 2021(after regime shift)were *** reveal that phosphorus content in sediment was lower than that those of Erhai Lake and Dianchi Lake,Yunnan,SW China,on the same plateau,and was lower than those of Taihu Lake,Chaohu Lake,and Poyang Lake in the middle-lower Changjiang(Yangtze)River *** phosphorus(Or-P)was the main form(up to 60%),followed by inactive phosphorus(Ina-P),and the active phosphorus(Act-P),the least,which is opposite to those of Taihu Lake and Poyang Lake in the middle-lower Changjiang River Plain in the eastern ***-P content was high,indicating a high potential risk of phosphorous *** the regime shift,the total phosphorus in sediment decreased from 0.87±0.13 to 0.70±0.13 g/*** proportion of Or-P and Act-P decreased from 68.23% to 65.32% and from 5.35% to 4.69%,*** contrast,the proportion of Ina-P increased from 26.42% to 29.99%.The Moran’s I index revealed that the heterogeneity of the spatial distributions of the total phosphorus(S-TP)and Act-P in the sediments before regime shift was significant(P0.05).The regime shift aggravated the eutrophication of the lake,the trophic level index(TLI)increased from 48.42 to 54.49(P<0.01),and the previously mesotrophic lake became a mildly eutrophic *** results of this study revealed the impact of regime shift in the lake from submerged macrophyte dominance to phytoplankton dominanc

关键词： Caohai Lake sediment phosphorus specification regime shift

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Distribution of lipids in modern soils from various regions with continuous climate (moisture-heat) change in China and their climate significance

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Science China Earth Sciences 2007年第4期50卷 600-612页

作者： WANG YongLi FANG XiaoMin BAI Yan XI XiaoXia ZHANG XiZheng WANG YouXiao center of basin-mountain system and environment Institute of Tibetan Plateau ResearchChinese Academy of SciencesBeijing 100085China Key Laboratory of Gas Geochemistry Institute of Geology and GeophysicsChinese Academy of SciencesLanzhou 730000China Key Laboratory of Western Resources and environment of Education Ministry College of Earth and Environment SciencesLan-zhou UniversityLanzhou 730000China

Total 26 modern soil samples were collected from various regions under different climate conditions from tropical to arid temperate in China and systematically analyzed for their organic matters by GC/MS in order to evaluate climatic impacts on soil organic components. Abundant lipids molecules were recognized, including n-alkanes, n-alkenones, and long-chain branched alkanes. We find the pre- dominance of main peaks of long-chain n-alkanes (nC29, nC31, nC33) and short-chain ones (nC16, nC17, nC18) records information of soil generation in warm-humid and cold-dry regions. The proportion of n-alkanes (nC16+nC17+nC18) to (nC29+nC31+nC33) varies in good agreement with moisture-heat conditions and thus probably can serve as a new index for climate change. The ratios of C21-/nC22+, nC17/nC31 and (nC15+nC17+nC19) / ( nC27+nC29 +nC31) of n-alkanes, indicating respectively input ratios of lower bacterial alga, aquatic organisms, and higher plants and terraneous organisms, co-vary well in different climate regions from forest to grassland and desert, suggesting that they have also reflected the difference of climates between monsoon region and inland one. The C21-/C22+ ratio of n-alkan-2-one records largely the discrepancy of temperature from north to south of China bordered by the Qinling mountains, but less humidity. The C21-/C22+ ratio of n-alkan-3-ones changes well with climatic factors, such as tem- perature and humidity. The biogenic source of series A-D long-chain branched alkanes may be derived from some kinds of special epiphyte that most likely live in weak oxic-anoxic and moisture-heat envi- ronments, suggesting their distribution record as well some information on climatic change. All these researches demonstrate that the distributions of lipids molecules in modern soils in China record well signals of climates from quite different climatic regions, and can serve as important climatic proxies to reveal climatic change over China.

关键词： lipids molecule modern soil climate (moisture-heat) continuously changing regions climate index China

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Characteristics of diffuse pollution of nitrogen and phosphorous from a small town in the hilly area of the central Sichuan basin,China

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Journal of mountain Science 2016年第2期13卷 292-301页

作者： YANG Xiao-lin SHEN Xi ZHU Bo Key Laboratory of mountain Surface Processes and Ecological Regulation Institute of Mountain Hazards and EnvironmentChinese Academy of Sciences Safety and Emergency Management Research center Henan Polytechnic University

Hydrological and hydro-chemical monitoring of nitrogen(N) and phosphorus(P) in a small urbanized catchment was conducted in the hilly area of the central Sichuan basin,China,from 2010 through *** diffuse N and P loadings in different forms of total nitrogen(TN) and phosphorus(TP),dissolved nitrogen(DN) and phosphorus(DP),as well as particulate nitrogen(PN) and phosphorus(PP) were calculated based on runoff discharges and chemical *** results revealed that the diffuse pollution concentrations of TN,DN,PN,TP,DP and PP exhibited large variations during rainfall events,with peak concentrations occurring during the initial *** all of the measured parameters,the event mean concentrations(EMCs) were observed to clearly vary among rainfall *** EMCs of TN,DN,PN,TP,DP and PP(for all of the observed rainfall events) were 10.04,6.62,3.42,1.30,0.47 and0.83 mg/L,*** losses of diffuse N and P exhibited clear seasonal patterns and mainly occurred during the period from July through September,when the losses totaled 99.3 and 9.6 kg/ha for TN and TP,respectively,accounting for 75% and 74% of the total annual *** mean annual loadings of TN and TP were 124.6 and 12.9 kg/ha,*** results indicate that residential areas in the hilly areaof the central Sichuan basin are subject to high diffuse N and P loadings,posing a serious risk to the receiving water *** buffering belts are recommended to incorporate into the urbanized catchment to reduce diffuse pollution.

关键词： Nitrogen transport Phosphorus transport Event mean concentration Pollution loading Pollution sources Non-point-source pollution Yanting Agro-ecological Station

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Application and verification of simultaneous determination of cellulose δ^(13)C and δ^(18)O in Picea shrenkiana tree rings from northwestern China using the high-temperature pyrolysis method

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Journal of Arid Land 2018年第6期10卷 864-876页

作者： XU Guobao LIU Xiaohong SUN Weizhen CHEN Tuo ZHANG Xuanwen ZENG Xiaomin WU Guoju WANG Wenzhi QIN Dahe State Key Laboratory of Cryospheric Science Northwest Institute of Eco-Environment and Resources Chinese Academy of Sciences School of Geography and Tourism Shaanxi Normal University Department of Geology and Earth system Science Interdisciplinary center University of Maryland Institute of mountain Hazards and environment Chinese Academy of Sciences

Stable isotopes in tree-ring cellulose provide important data in ecological,archaeological,and paleoenvironmental researches,thereby,the demand for stable isotope analyses is increasing *** measurement of cellulose δC and δO values from tree rings would reduce the cost of isotopic commodities and improve the analytical efficiency compared with conventional separate *** this study,we compared the δC and δO values of tree-ringα-cellulose from Tianshan spruce(Picea schrenkiana)in an arid site in the drainage basin of the Urumqi River in Xinjiang of northwestern China based on separate and simultaneous measurements,using the combustion method(at1050°C)and the high-temperature pyrolysis method(at 1350°C and 1400°C).We verified the results of simultaneous measurement using the outputs from separate measurement and found that both methods(separate and simultaneous)produced similar δC *** two-point calibrated method improved the results(range and variation)of δC and δO *** mean values,standard deviations,and trends of the tree-ring δC obtained by the combustion method were similar to those by the pyrolysis method followed by two-point *** simultaneously measured δO from the pyrolysis method at 1400°C had a nearly constant offset with that the pyrolysis method at 1350°C due to isotopic-dependence on the reaction ***,they showed similar variations in the time *** climate responses inferred from simultaneously and separately measured δC and δO did not differ between the two *** tree-ring δC and δO values were negatively correlated with standardized precipitation evapotranspiration index from May to *** addition,the δO was significantly correlated with temperature(positive),precipitation(negative),and relative humidity(negative)from May to *** tree-ring δC and δO values determined simultaneously through the high-temperature pyrolysis method could produce acceptable and reliable sta

关键词： tree rings stable carbon and oxygen isotopes combustion pyrolysis simultaneous determination calibration Picea schrenkiana

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Dynamic process simulation with a Savage-Hutter type model for the intrusion of landslide into river

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Journal of mountain Science 2016年第7期13卷 1265-1274页

作者： LIU Wei He Si-ming Ou Yang Chao-jun Key laboratory of mountain Hazards and Surface Process Chinese Academy of Science Institute of mountain Hazards and environment Chinese Academy of Sciences center for Excellence in Tibetan Plateau Earth Sciences Chinese Academy of Sciences

Natural damming of rivers by mass movements is a very common and potentially dangerous phenomena which has been documented all over the world. In this paper, a two-layer model of Savage-Hutter type is presented to simulate the dynamic procedure for the intrusion of landslide into rivers. The two-layer shallow water system is derived by depth averaging the incompressible Navier-Stokes equations with the hydrostatic assumption. A high order accuracy scheme based on the finite volume method is proposed to solve the presented model equations. Several numerical tests are performed to verify the realiability and feasibility of the proposed model. The numerical results indicate that the proposed method can be competent for simulating the dynamic process of landslide intrusion into the river. The interaction effect between both layers has a significant impact on the landslide movement, water fluctuation and wave propagation.

关键词： Landslide Two-layer model Savage Hutter type Numerical simulation

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Catastrophic Debris Flows on July 10^(th) 2013 along the Min River in Areas Seriously-hit by the Wenchuan Earthquake

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Journal of mountain Science 2015年第1期12卷 186-206页

作者： GE Yong-gang CUI Peng ZHANG Jian-qiang ZENG Chao SU Feng-huan Key Laboratory of mountain Hazards and Earth Surface Processes/Chengdu Institute of mountain Hazards and environment Chinese Academy of Sciences CAS center for Excellence in Tibetan Plateau Earth Sciences Sichuan Engineering Research center for Emergency Mapping & Disaster Reduction

Over 240 debris flows occurred in hill-slopes, gullies （ indicated those with single-channel） and watersheds （indicated those with tributaries and channels） on July 10th 2013 in the Wenchuan county, and caused 29 casualties and about 633×10^6 USD losses. This work aimed to analyze characteristics, hazards and causes of these events and explore mitigating measures based on field investigation and remote sensing images interpretation. The debris flows contained clay content of 0.1%~3.56%, having densities of 1.72-2.14 t/m^3, velocities of 5.0-m.7 m/s, discharges of 335-2353 m^3/s and sediment yields of 0.10-1.26×10^6 m^3, and also numerously occurred in large watersheds with the area over lo km^2. Large debris flows formed 3 hazard-chains in slopes, gullies, watersheds and rivers, which all evolved in dammed lakes and outburst flood, and 26 dammed lakes and lO newly ones were generated along the rivers of Min and Yuzi. The remarkable spatial difference of loose solid materials accumulation and intense rainfall, with the cumulative of about or more than 150 mm and the hourly of over 16mm, caused debris flows in the sections from Yingxiu to Miansi and Gengda. The damages on buildings, reconstructions, highways,factories and hydro power station originated from the impacting, scouring, burying of debris flows, the submerging of dammed lake and the scouring of outburst flood, and the huge losses came from the ruinous destructions of control engineering works of debris flows as well as the irrational location and low- resistant capabilities of reconstructions. For hazards mitigating of debris flows in long term, the feasible measures for short term, including risk-reassessing of foregone and potential hazard sites, regional alarming system establishing and integrated control in disastrous sites, and middle-long term, including improving reconstruction standard, rationally disposing river channel bed rise and selecting appropriate reconstruction time and plans, were strongly

关键词： Debris flows Wenchuan Earthquake Characteristics Damages Causes Preventions

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Forecast Method of Multimode system for Debris Flow Risk Assessment in Qingping Town,Sichuan Province,China

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Journal of mountain Science 2011年第4期8卷 592-602页

作者： KONG Jiming Key Laboratory of mountain Hazards and Earth Surface Processes Chinese Academy of Sciences Institute of mountain Hazards and environment Chinese Academy of Sciences

The Wenchuan Earthquake of May 12,2008 triggered large numbers of *** heavy rain on 13 August 2010 triggered debris flows with total volume of more than 6 million cubic meters and the debris flows destroyed 500 houses and infrastructure built after the Wenchuan *** study area Qingping Town was located in the northwestern part of the Sichuan basin of China,which needs the second reconstructions and the critical evaluation of debris *** study takes basin as the study unit and defines collapse,landslide and debris flow hazard as a geo-hazard system.A multimode system composed of principal series system and secondary parallel system were established to evaluate the hazard grade of debris flow in 138 drainage basins of Qingping *** evaluation result shows that 30.43% of study basins(42 basins) and 24.58% of study area,are in extremely high or high hazard grades,and both percentage of basin quantity and percentage of area in different hazard grades decrease with the increase of hazard *** to the geo-hazard data from the interpretation of unmanned plane image with a 0.5-m resolution and field investigation after the Wenchuan Earthquake and 8.13 Big Debris Flow,the ratio of landslides and collapses increased after the Wenchuan Earthquake and the ratios of extremely high or high hazard grades were more than moderate or low hazard grades obviously.23 geo-hazards after8.13 Big Debris Flow in Qingping town region all occurred in basins with extremely high or high hazard grades,and 9 debris flows were in basins with extremely high hazard *** model of multimode system for critical evaluation could forecast not only the collapse and landslide but also the debris flow precisely when the basin was taken as the study unit.

关键词： Multimode system Risk assessment Debris flow Landslide Wenchuan Earthquake Qingping Town

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Coseismic landslide sediment increased by the“9.5”Luding earthquake,Sichuan,China

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Journal of mountain Science 2023年第3期20卷 624-636页

作者： XIONG Jiang CHEN Hua-yong ZENG Lu SU Feng-huan GONG Ling-feng TANG Chen-xiao Key Laboratory of mountain Hazards and Earth Surface Processes Institute of Mountain Hazards and EnvironmentChinese Academy of SciencesChengdu 610299China Chengdu Geological Survey center China Geological SurveyChengdu 610081China

The"9.5"Luding earthquake(Ms 6.8),which occurred on September 5,2022,has triggered thousands of landslides,and caused coseismic landslide sediment in the mountain basin to increase *** the Luding earthquake,landslide sediment may continue to divert to channels,and increase the activity of debris ***,the formation of debris flows can pose a major threat to infrastructure,lives and *** better understand the landslide sediment that increased by the"9.5"Luding earthquake and its impact on the activity of debris flows,we mapped the coseismic landslide database using satellite images.A total of9142 landslides with an area of 49.51 km^(2),covering4.81%of the whole basin,were triggered by the Luding *** coseismic landslides induced by this earthquake are dominated by shallow landslides and are densely distributed in the combined zone of the Xianshuihe fault and the Daduhe *** 333.31×10^(6)m^(3)(error:111.43×10^(6)m^(3)/-70.73×10^(6)m^(3))of coseismic landslide sediments were induced by the earthquake in the epicenter,and the landslide materials were concentrated downstream of the *** *** than 13986.45×10^(4)m^(3)(error:4675.67×10^(4)m^(3)/-2967.92×10^(4)m^(3))of landslide sediment may supply for debris flow ***,the small basins that are distributed near Moxi,Detuo and the junction of the Xianshuihe fault and Daduhe fault are more susceptible to debris flows when rainstorms hit these ***,prevention and mitigation measures,early warning,and land use planning should be adopted in advance in these ***,from the perspectives of landslide scale and the degree of landslide-channel coupling,the activity or active intensity of debris flows in the Luding earthquake area may be lower than that in the epicenter area of the 2008 Wenchuan earthquake.

关键词： Luding earthquake Landslide sediment Debris flow activity Remote sensing image

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What is the relationship between ecosystem services and urbanization? A case study of the mountainous areas in Southwest China

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Journal of mountain Science 2019年第12期16卷 2867-2881页

作者： PENG Li WANG Xu-xi Institute of mountain Hazards and environment Chinese Academy of SciencesChengdu 610041China College of Land and Resource China West Normal UniversityNanchong 637009China Institute of Jialing River basin China West Normal UniversityNanchong 637009China

China is undergoing a rapid urbanization process,and urbanization will have a direct impact on regional ecosystems and affect regional ecosystem *** the mountainous counties in Southwestern China as the research object,this study reveals the spatial clustering characteristics of four typical ecosystem services(food production,soil conservation,water yield and carbon sequestration)as well as the trade-offs and synergies among ecosystem services in different urbanized *** the same time,piecewise linear regression is used to determine the threshold of the influence of urbanization on ecosystem *** results indicate that:1)There are spatial autocorrelations among the four typical ecosystem services;with strong clustering characteristics,the positive correlation types are"clustered"locally;and with significant spatial heterogeneity,the negative correlation types are scattered and mainly appear in the highly urbanized area.2)There are also remarkable differences in the relationship among various ecosystem services in different urbanized areas,and in particular,there are marked trade-offs between food production and carbon sequestration in the moderately urbanized area and the highly urbanized ***,there are synergies between them in the lowly urbanized area.3)With an increase in the compounded night light index(CNLI),water yield,carbon sequestration,food production and overall ecosystem services values present an increasing-decreasing trend,the soil conservation function value shows a decreasing-increasing *** response of water yield,carbon sequestration,food production,and overall ecosystem services to the compounded night light index(CNLI)has a threshold of 1.2642,1.4833,1.3388,1.5146 and 1.2237,*** on the detected relationships between urbanization and ecosystem services,this study provides a theoretical reference for the selection of urbanization development models in key ecological functional areas.

关键词： Ecosystem services Urbanization Spatial clustering pattern Trade-offs/synergies Southwestern China

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Cascading adaptation of rural livelihood to changing environment:Conceptual framework and experiment from the Koshi River basin

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Advances in Climate Change Research 2020年第2期11卷 141-157页

作者： FANG Yi-Ping ZHU Ran ZHANG Chen-Jia Golam RASUL Nilhari NEUPANE Institute of mountain Hazards&environment Chinese Academy of SciencesChengdu610041China College of Resource and environment University of Chinese Academy of SciencesBeijing100049China University of Chinese Academy of Sciences Beijing100049China International Centre for Integrated mountain Development GPO Box3226KathmanduNepal center of Research for environment Energy and WaterKathmandu44600Nepal

Rural communities in the Koshi River basin,a trans-boundary river basin in the Hindu Kush-Himalayas,have been experiencing unprecedented difficulties for adapting with the livelihood challenges arising from floods,droughts and other climatic,environmental and socio-economic *** single purpose adaptation approach often fails to address the multiple challenges arises from cascading effects of climate change at different scales and *** fill this gap,we developed a multi-dimensional flexible adaptation framework looking at the four dimensions of adaptation,structure,issue,time,and space(SITS).The SITS framework provides a comprehensive approach for cascading adaptation at trans-boundary river basin level and it could effectively enhance the adaptive capacity and transform livelihood outcome if properly *** the SITS framework,we examined four cascading adaptation pathways for:i)reducing disaster stressors on livelihoods,ii)enhancing access to crucial livelihood capitals,iii)improving equal rights to livelihood,and iv)strengthening synergies and exploiting complementarities at trans-boundary river basin *** findings revealed that in the context of changing climate,it is necessary to employ different livelihood adaptation strategies and multiple responses simultaneously or sequentially to successfully adapt to the cascading effects of changing *** cascading adaptation may provide a sound basis on which to cope with the climate uncertainty through realistic scenarios of structure,issue,time and *** implementation,however,has several obstacles,for example,differences in national system,investment capacity,complexity of trans-boundary basin,remained particularly in trans-boundary river basin where managing transnational trade-offs and harness spatial synergies are critically important.

关键词： Cascading adaptation Rural livelihood Trans-boundary river basin SITS framework

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