Carbon,nitrogen and phosphorus stoichiometry in Pinus tabulaeformis forest ecosystems in warm temperate Shanxi Province,north China

Although carbon(C), nitrogen(N), and phosphorous(P) stoichiometric ratios are considered good indicators of nutrient excess/limitation and thus of ecosystem health, few reports have discussed the trends and the reciprocal effects of C:N:P stoichiometry in plant–litter–soil systems. The present study analyzed C:N:P ratios in four age groups of Chinese pine, Pinus tabulaeformis Carr., forests in Shanxi Province, China: plantation young forests(AY,<20 year-old); plantation middle-aged forests(AM, 21–30 year-old); natural young forests(NY,<30 year-old); and natural middle-aged forests(NM,31–50 year-old). The average C:N:P ratios calculated for tree, shrub, and herbaceous leaves, litter, and soil(0–100 cm) were generally higher in NY followed by NM,AM, and AY. C:N and C:P ratios were higher in litter than in leaves and soils, and reached higher values in the litter and leaves of young forests than in middle-aged forests;however, C:N and C:P ratios were higher in soils of middle-aged forests than in young forests. N:P ratios were higher in leaves than in litter and soils regardless of stand age; the consistent N:P<14 values found in all forests indicated N limitations. With plant leaves, C:P ratios were highest in trees, followed by herbs and shrubs, indicating a higher efficiency in tree leaf formation. C:N ratios decreased with increasing soil depth, whereas there was no trend for C:P and N:P ratios. C:N:P stoichiometry of forest foliage did not exhibit a consistent variation according to stand age. Research on the relationships between N:P, and P, N nutrient limits and the characteristics of vegetation nutrient adaptation need to be continued.

TPFTZ(Tianjin Port Free Trade Zone)——A New Pattern of China's Openning to the Outside World

Under the guidance of Deng Xiao-ping’s strategic think-ing of openning to the outside world, the structure of om-nibearing openness has basically taken shape in China. Follow-

Special Economic Zones——New growth points in China's economy

It was approved by the State Council in1984 to establish economic andtechnological development zones in 14coastal port cities to function as windows forthose cities to attract foreign investment,introduce advanced technology andmanagement methods and expand the export-oriented economy. Since 1992, 18 otherdevelopment zones have been approved bythe Council, increasing the number of suchzones to 32.

A Comprehensive Bibliometric Analysis of China’s Free Trade Zones:Status and Evolutionary Trends

The China free trade zone,crucial for advancing a new open economy,has gained significant attention lately.We analyzed 885 papers from Peking University Core and CSSCI journals(2012-2023)using CiteSpace for visualization.Our research results indicate that the literature on China’s free trade zone peaked with 171 articles in 2015,and gradually returned to an average of 45 articles per year.The main research focuses in this field include“institutional innovation”,“negative list”,“financial innovation”,“financial openness”,“opening up to the outside world”,and“economic growth”.In addition,cutting-edge analysis indicates that“dual circulation”and“blockchain”are future research trends.The main authors of the literature include Yang Bin,Zhu Xiaolin,Yuan Bo,Li Meng,Zhao Liang,and others.Their affiliated institutions,research institutes,and universities have not yet formed a clear core circle of authors;The top three research institutions with the highest number of publications are the International Trade and Economic Cooperation Research Institute of the Ministry of Commerce,Kaiyuan Law School of Shanghai Jiao Tong University,and the Comprehensive Research Institute of the Free Trade Zone of Sun Yatsen University.This article delves into the current hot topics and progress in the research of China’s free trade zones,providing important references and inspirations for future scholars in this field.

Conversion relationship of rainfall-soil moisture-groundwater in Quaternary thick cohesive soil in Jianghan Plain,Hubei Province,China

The scientific field test site of rainfall-soil moisture-groundwater conversion in Dabie Mountain Area–Jianghan Plain is located in the northern region of the Jianghan Plain,the transition zone between the Dabie Mountain Area and Jianghan Plain.It’s a great field test site to study the material and energy exchange among rainfall,soil moisture,and groundwater of the Earth’s critical zone in subtropical monsoon climate plain areas.This paper analyzed the connection between rainfall and volume water content(VWC)of soil at different depths of several soil profiles,and the dynamic feature of groundwater was discussed,which reveals the rainfall infiltration recharge of Quaternary Upper Pleistocene strata.The results show that the Quaternary Upper Pleistocene aquifer groundwater accepts a little direct rainfall recharge,while the lateral recharge is the main supplement source.There were 75 effective rainfall events among 120 rainfall events during the monitoring period,with an accumulated amount of 672.9 mm,and the percentages of effective rainfall amount and duration time were 62.50%and 91.56%,respectively.The max evaporation depth at the upper part in Quaternary cohesive soil was no less than 1.4 m.The soil profile was divided into four zones:(1)The sensitive zone of rainfall infiltration within 1.4 m,where the material and energy exchange frequently near the interface between atmosphere and soil;(2)the buffer zone of rainfall infiltration between 1.4 m and 3.5 m;(3)the migration zone of rainfall infiltration between 3.5 m and 5.0 m;and(4)the rainfall infiltration and groundwater level co-influenced zone below 5.0 m.The results revealed the reaction of soil moisture and groundwater to rainfall in the area covered by cohesive soil under humid climate in Earth’s critical zone,which is of great theoretical and practical significance for groundwater resources evaluation and development,groundwater environmental protection,ecological environmental improvement,drought disaster prevention,and flood disaster prevention in subtropical monsoon climate plain areas.

Study on Water Consumption Coefficient of People's Living and Its Regional Disparity in the North of China

By employing the information-reshufflingmethod that integrates census data, precipitation dataand inquiry data of water consumption, this paperdiscusses 5 (water consumption coefficient of people’sliving) in allusion to different precipitation zones anddifferent periods of time. The study shows that 5-(water consumption coefficient of urban people’sliving), 5. (water consumption coefficient of ruralpeople’s living) and increase with time passing, andthe increasing extent of 5 is 1.84, 2.62, 2.84 and 2.68times respectively from the west to the east, whichresults from the total quantity of water resources andthe speed of urbanization. 5- and 5. of eachprecipitation zone increased with 5- increasing morequickly than 5., and the difference between the twoalso increased when time passed. In the past fifty years(1950-2000), the increasing extent of 5- was 1.71,2.96, 2.41 and 2.33 times respectively from the westto the east, in which 200-400mm precipitation zoneincreased more than others. Meanwhile the increasingextent of 5. is 1.55, 1.60, 1.53 and 1.64 timesrespectively from the west to the east with eachprecipitation zone increasing similarly. The change of5-is due to the speed of urbanization and the stabilityof water resources. This study provides basis forcalculating the water demand of people’s living andrevealing the impact of water demand of people’s livingon ecological drought in different zones.

The Implementation Mode of No-Fly Zones in International Relations

A No-Fly Zone(NFZ)is a unique mode of humanitarian intervention which is understudied in international relations.This article focuses on the political dimension of NFZs in international relations and investigates their implementations by empirically reviewing all three cases of NFZs to date.There may be efforts by intervening states to highlight humanitarian crises among certain targets to secure UN authorization for the NFZs;yet the implementation of NFZs is also driven largely by the security interests of enforcing states.As a result,there is the potential for those states implementing NFZs to transcend legal authorization and sometimes use excessive force,with likely calamitous results for local populations,or in extreme cases,accomplishing regime change by supporting opposition parties in target states.

南海北部陆缘反“S”型构造带及其对地震活动的影响

通过地形—地貌、断裂构造、地壳结构、中新生代沉积盆地、第四纪地质特征等分析,认为南海北部陆缘存在滨岸岛链、陆坡北缘和陆坡南缘三条反“S”型构造带,它们形成于晚第三纪,较“新华夏系”和“南海系”晚。上新世末期以来,反“S”型构造带的活动方式,对南海北部陆缘第四纪地质特征影响显著,同时控制了这一区域的地震活动方式和地震带展布,其中,“滨海地震带”和“雷琼地震带”同属于滨岸岛链带,“台西滨外地震带”和“东沙—海南地震带”同属于陆坡北缘带。

南海北部陆缘反“S”型构造带的提出及其在新生代晚期地质演化中的作用

通过地震剖面、地形－地貌、断裂构造、地壳结构、中新生代沉积盆地、第四纪地质特征等分析，认为南海北部陆缘存在滨岸岛键、陆坡北缘和陆坡南缘三条反“S”型构造带。它们形成于晚第三纪，较“新华夏系”和“南海系”晚。反“S”型构造带新生代晚期的活动方式，对南海北部陆缘的地质演化影响显著，同时控制了这一区域的灾害性地质因素的活动方式和分布。

基于MODIS影像的夜间云检测算法研究

在以往云检测算法的基础上,利用MOD IS传感器高光谱和高时间分辨率的特点,建立一套针对MOD IS夜间影像的,以单、多时相组合方法为基础的夜间云检测算法。通过对我国南北地震构造带(南北带)影像进行云检测试验证实,该算法对MOD IS夜间影像上的各种云类具有较好的检测效果。

论海洋自然保护地分类分区管控的中国方案

海洋自然保护地分类分区管控既有空间规划的自然科学依据,又有区域治理的社会科学依据,且与精细化建设之间具有手段与目的的关系。分类施策、分区治理,精细化建设,是我国海洋自然保护地分类分区管控的改革方向。海洋自然保护地分类分区管控以新型海洋自然保护区制度、海洋公园制度接替海洋特别保护区制度,与国土空间规划制度、生态保护红线制度等衔接,并将生态功能保护区作为我国新时代自然保护地体系中的类型之一。分类分区管控基于陆海统筹战略提出分区差异化管控、精细化建设的中国方案,并通过完善立法保障其实现。

北京松山林地nirK型反硝化微生物群落立地及林型效应

[目的]探究北京松山林地土壤nirK型反硝化微生物群落特征及影响因子,为华北暖温带森林土壤生态系统氮循环过程和环境变化提供依据。[方法]在北京松山国家级自然保护区选择油松林、山杨林、蒙古栎林3种典型林型,分别设置3块(20 m×20 m)标准地进行调查,采集0~20 cm表层混合土样,分析土壤性质并提取土壤微生物总DNA,PCR扩增反硝化过程关键酶亚硝酸盐还原酶的编码基因nirK片段,采用第2代高通量测序分析不同林型土壤nirK型反硝化微生物群落组成和多样性,探究林型和土壤性质对反硝化微生物群落特性的影响。[结果]1)从油松林、山杨林和蒙古栎林9个土壤样本中共得到nirK基因有效序列993 401条、优质序列770 328条。3种林型土壤nirK基因共检测出7门78属,在已鉴定的微生物中各林型优势菌为变形菌门,其相对丰度在3种林型中均达50%,在油松林中最高为58.2%;优势属主要为慢生根瘤菌属、中生根瘤菌属和红假单胞菌属,总相对丰度达50%以上,其中核心菌属为慢生根瘤菌属。2) nirK型反硝化微生物α多样性分析显示,油松林Shannon(7.59±0.56)、 Simpson(0.98±0.01)、 Chao1(2 164.24±214.08)指数均显著高于山杨林(5.23±0.26、 0.89±0.02、1 650.56±136.69)和蒙古栎林(5.76±0.38、 0.93±0.02、 1 621.36±156.70)(P<0.05)。基于Bray-Curtis距离算法并采用PCoA分析显示,不同林型土壤反硝化微生物群落组间差异大于组内。3)林分因子、土壤性质与土壤反硝化微生物的冗余分析结果表明,土壤碱解氮、硝态氮和有机质等土壤性质是影响nirK型反硝化微生物群落组成的关键因子(P<0.05)。[结论]北京松山油松林、山杨林和蒙古栎林土壤nirK型反硝化微生物群落组成、多样性存在明显差异,林型与碱解氮、硝态氮和有机质等土壤性质是影响土壤nirK型反硝化微生物群落特征的重要因素。

Distribution patterns of SOC/TN content and their relationship with topography,vegetation and climatic factors in China’s north-south transitional zone

The spatial distributions and variation mechanism of key soil indices in the Qinling-Daba Mountains are important indicators for the identification of the transitional effect and regional characteristics of the north–south transitional zone in China.This manuscript analyzes the spatial variations in soil organic carbon(SOC)and total nitrogen(TN)and corresponding relationships with major geographical factors based on spatial analysis and geostatistics considering data obtained from the Second National Soil Survey.The results indicate that the spatial distributions of the SOC and TN contents are consistent,and three high-content areas,one secondary high-content area and one low-content area are observed.High content values are located in the high-altitude regions of the Qinling-Daba Mountains and mountainous areas to the west of the Jialing River,the low-content area occurs on the north slope of the Qinling Mountains,and the secondary high-content area mainly encompasses both sides of the Hanjiang River and regions in the Qinling-Daba Mountains at altitudes below 1000 m.The SOC and TN contents vary between the above two ranges,with the gradual increase in content revealing a horn-shaped pattern.Considering the spatial variations and functions of vegetation,topography and climate factors,it is found that the SOC/TN range in the secondary high-content area remains consistent along the 1000 m contour line,the upper limit of the transitional mountain altitudinal belt,the 0℃isotherm line in January and the 24℃isotherm line in July.This region constitutes the main body of the transitional zone between the subtropical and warm temperate zones,and the northern boundary is roughly distributed along the Dujiangyan-Maoxian-Pingwu-Wenxian line to the west of the Jialing River and the 1000 m contour line on the southern slope of the Qinling Mountains,while the southern boundary occurs along the Dujiangyan-Beichuan-Qingchuan line to the west of the Jialing River and the 1000 m contour line on the northern slope of the Daba Mountains.SOC/TN spatial variation provides a reference for the demarcation of the subtropical and warm temperate zones,and further identification of the soil processes and ecological effects in typical regions can help reveal multidimensional transitional characteristics and variation mechanisms.

Characterization of Fe-S minerals influenced by buried ancient woods in the intertidal zone,East China Sea

An ancient wood layer dated at about 5600 cal. a BP by AMS14C dating was discovered in the intertidal zone, East China Sea. Samples affected by ancient woods, including fresh coast bedrock, weathering bedrock, seepage water from coast, seepage water from ancient wood layer, intertidal seawater, fresh water, beach mud, ancient wood barks and ancient peat, were collected for geochemical analysis. The beach mud and the bacteriogenic iron oxides (BIOS) in coastal seepage water were analyzed by min-eralogical and high-resolution transmission electron microscopy (HRTEM)-selected area electron dif-fraction (SAED) analysis. Inorganic sulfur compositions and δ34S of the ancient peat and the beach mud were determined. The results showed that Fe, Mn, S (SO42-) were enriched in the intertidal area at different levels, very likely caused by fermentation of ancient woods. The presence of abundant iron-oxidizing bacteria (FeOB) and sulfate-reducing bacteria (SRB) in this intertidal zone was confirmed by HRTEM-SAED observation, and these bacteria were involved in Fe-S cycle to induce extracellular biomineralization. The negative δ34SV-CDT (-2.9‰) likely indicated the biogenic origin of iron-sulfide minerals in the beach mud at high sulfate reduction rate (SRR). These findings are helpful for under-standing the biogeochemical Fe-S cycle and biomineralization process at high organic matter deposition rate and high SRR in the intertidal zone, estuary, or near shoreline.

华北东部上地幔破裂带

利用天然地震的走时和S波震相的层析成像方法可以提供上地幔S波速度扰动精细图像。我们对华北东部(32°～44°N,114°～126°E)进行了高分辨率S波地震层析成像研究,揭示了苏鲁及环渤海地区上地幔速度结构的差异,为研究该区域深部构造演化提供新的地球物理证据和制约。本次成像取得的最醒目的成果是揭示了由波速剧烈变化指示的两条上地幔破碎带,它们分别出现在渤海湾裂谷区与苏鲁超高压变质带下方。苏鲁超高压变质带下方上地幔破碎带包含多个有序排列的高速团块,推测与扬子走滑并向前俯冲、以及前锋超高压变质块体拆沉及折返作用有关。地幔地震S波速的成像结果支持华北东部渤海湾地区发育地幔热羽柱体系的观点,并对地幔热羽柱的鉴识提供了新的标识。

东北地区冬季降雪的气候特征及其区划

根据东北地区197个气象观测站1961-2006年冬季(12-2月)的逐日降雪量资料,采用线性趋势、小波分析、突变分析、t-检验、EOF(经验正交函数)、REOF(旋转经验正交函数)和CAST(聚类统计检验)等气候统计方法,对东北地区近45 a来冬季降雪的气候特征进行了研究。结果表明:东北地区近45 a冬季降雪呈下降趋势,每10 a下降0.2mm。降雪具有明显的阶段性,1960年代中期到1970年代中期为偏少时段,1970年代中期以后到1980年代中期为偏多时段,1980年代中期至1990年代降雪基本持平,在2000年之后降雪量有所增加。东北地区冬季降雪在45 a间始终存在着10 a左右的长周期,1980年代以后存在着6 a左右的周期,而在1970-1980年代和1990年代之后存在着4 a的短周期。EOF分析结果表明:全区一致由北向南的正变化趋势为主要模态,大值区主要位于吉林东部和辽宁西北部,西北-东南反向变化,黑龙江北部同其它区域表现出反向变化特征,也是重要的异常模态。REOF/CAST方法的区划表明:东北地区降雪主要分为4个区域,分别为辽宁-吉林东部、吉林北部-黑龙江南部、辽宁西南部和黑龙江北部地区,不同区域降雪量的变化趋势存在差异。

中国暖温带若干灌丛群落多样性问题的研究

暖温带灌丛的生物多样性的研究表明：１．灌丛群落的均一度指数同优势度指数的相关性较丰富度指数同变化度指数的相关性为高；在众多的多样性指数中，Ｄ４（Ｓｈａｎｎｏｎ信息度指数）和Ｄ６（Ｇｉｎｉ指数）因最大限度地包含了其它各类多样性指数的信息而被采用。２．灌丛群落的物种多样性指数值随着演替的进行，没有表现出降低的趋势。３．生物多样性较高的荆条灌丛和辽东栎萌丛的物种多度分布是对数分布，而生物多样性较低的鬼见愁灌丛和毛榛灌丛的物种多度分布是几何分布，处于中间的三桠绣线菊灌丛的物种多度分布是Ｂｒｏｋｅｎ－Ｓｔｉｃｋ分布；没有正态对数分布类型。