祁连山疏勒河上游高寒草甸CO2通量变化特征

采用涡动相关法对疏勒河上游高寒草甸生态系统2009年CO2通量进行连续观测.结果表明:疏勒河上游高寒草甸CO2通量呈明显的日和月变化特征.生长季CO2通量具有明显的日变化过程,其中吸收峰值从5月的10:00时逐步推后到7月的12:00左右,CO2通量排放峰值则出现在21:00-22:00.其中,最大吸收和排放速率均出现...     

青南退化高寒草甸植被土壤固碳潜力

青南与青北高寒草甸植被、 土壤、 气候类型相似, 地植被、 土壤碳密度可比性强. 研究表明, 青南高寒草甸植被退化严重, 植被和土壤碳密度随退化程度的加剧而降低, 轻度、 中度、 重度和极度退化植被碳密度分别为921.281、 809.998、 237.974 gC·m^-2和75.972 gC·m^-2, 0~40 cm土壤碳密度分别为16.760、 16.145、 14.360 gC·m^-2和12.945 kgC·m^-2. 在青北未退化草甸植被和0~40 cm层次土壤碳密度分别为1 149.327 gC·m^-2和20.305 kgC·m^-2. 相对青北高寒草甸植被类型而言, 青南高寒草甸轻度、 中度、 重度、 极度退化的植被固碳密度分别增加228.046、 339.329、 911.354 gC·m^-2和1073.355 gC·m^-2, 而对应0~40 cm层次土壤固碳密度可分别增加3.545、 4.160、 5.946 gC·m^-2和7.359 kgC·m^-2. 以青南当地未退化草地而言, 轻度、 中度、 重度和极度退化的高寒草甸0~20 cm层次土壤固碳密度可达1.694、 2.087、 3.537 kgC·m^-2和4.282 kgC·m^-2, 表现出较大的固碳潜力.     

夏季长江口潮间带CH4、CO2和N2O通量特征

使用原位静态箱现场采样,对夏季(7月和8月)长江口崇明东滩湿地3种主要温室气体CO2、CH4和N2O的界面通量进行了同步观测.结果表明,夏季低潮滩是大气CH4的排放源(40.2 μg/(m2·h)),CO2和N2O的吸收汇(通量值分别为-86.3 mg/(m2·h),-27.6 μg/(m2·h)).7月和8月中潮滩是3种温室气体的排放源,CH4日平均排放速率达到6.56 mg/(m2·h),CO2为301 mg/(m2·h),N2O为69.9 μg/(m2·h).温度(气温和不同深度地温)、沉积物有机碳含量以及潮滩植被海三棱藨草和沉积物表层藻类的光合和呼吸是决定CH4、CO2、N2O产生、排放和吸收的主要因素.相关分析表明中潮滩气体排放通量与温度(气温和不同深度地温)呈显著正相关关系,但在低潮滩气体通量与温度的相关关系不明显.     

长江源区典型高寒沼泽草甸地表能量平衡特征及其影响因素

广泛分布的草地是长江源区水源涵养的重要生态系统之一。在气候变暖的背景下,高寒草地生态系统的空间分布格局发生了深刻的变化,高寒沼泽草甸显著退化,正面临着逐步消失的风险,并且目前对于高寒沼泽草甸能量平衡过程及其演化过程的观测不足,难以支撑进一步的机理研究。通过开展高寒沼泽草甸地区的能量平衡观测研究,深入理解高寒沼泽草甸能量平衡和水量平衡过程特征并分析影响因素和驱动力,能够为沼泽草甸的保护和修复提供数据基础和理论支撑。本研究基于长江源区布曲冬克玛底河流域典型高寒沼泽草甸2020年涡动相关设备测量所获取的连续、高质量的能量平衡观测数据,探究了当地能量平衡特征及其影响因素。研究发现：冬克玛底流域的气候特征呈现夏秋季温润、冬春季冷干的季节特征,下垫面土壤存在长时间的饱和状态以及明显的冻融循环过程。独特的气候及下垫面条件使高寒沼泽草甸具有独特的能量平衡特征,表现在净辐射主要被感热和潜热所消耗,分别达到全年的46.1%和55.6%,仅有1.7%转化为土壤热通量。净辐射在夏秋季主要转化为潜热,冬春季主要转化为感热,潜热通量相较于其他高寒草甸类型占比更大且更集中在夏秋季,高寒沼泽草甸年总潜热占比可达有效辐...     

翻耕补播对青藏高原疏勒河上游高寒草甸土壤可培养微生物数量的影响

高寒草甸是青藏高原面积最大的草地类型, 对全球生态环境的影响十分巨大。然而在外界干扰下, 使得本身就很脆弱的高寒草甸发生了不同程度的退化。为探究翻耕补播对土壤微生物的影响, 以疏勒河上游不同季节（4月、 6月、 9月）原生高寒草甸、 退化草甸和翻耕补播草甸土壤为对象, 研究了土壤可培养细菌数量的季节变化及其影响因素。结果表明： 研究区域可培养细菌数量介于4.3×10⁶ ~ 4.5×10⁷ CFU·g^-1之间, 不同季节退化草甸与翻耕补播草甸土壤细菌数量均显著低于原生高寒草甸, 且不同类型高寒草甸生态系统下可培养细菌具有明显的季节差异： 原生高寒草甸生态系统下土壤细菌在6月生物量最高, 4月最低; 而退化草甸与翻耕补播草甸土壤细菌生物量并没有表现出明显的季节波动; 相关分析表明, 可培养细菌数量与土壤全氮、 植被盖度及土壤含水量存在极显著正相关关系。研究发现, 翻耕补播措施并没有恢复该区域微生物数量, 研究结果对于认识高寒草甸生态系统的退化成因, 判断恢复措施的有效性和合理性具有重要意义。     

祁连山水合物分布区不同高寒生态类型冬季表层土壤中古菌群落及变化特征

祁连山冻土区是我国青藏高原重要永久冻土区之一,也是我国陆域天然气水合物分布的重要地区。前期调查表明祁连山木里天然气水合物钻井区一带具 有丰富多样的高寒冻土生态类型。为了解该地区高寒草甸和高寒沼泽草甸表层土壤中古菌群落的多样性及分布特征,对2014年初冬在该区采集的表层土壤样品利用16S rRNA分子生物学技术和 地球化学等方法进行了分析和研究。结果显示,高寒草甸区土壤呈中性,而高寒沼泽草甸区土壤呈弱酸性。钻井区土壤中的TOC和顶空气甲烷含量均显著高于背景区,而在背景区内的两种生态 类型土壤中的TOC和顶空气甲烷含量差别较小。钻井区(除1个点)微生物细胞丰度高于背景区2~5倍。冬季表层土壤中的古菌多样性较低,含泉古菌的3个类群和广古菌的3个类群。不同植被类型 古菌群落的优势种群显著不同,在高寒草甸区为泉古菌门的Group Ⅰ.1b,而高寒沼泽草甸区为广古菌门的甲烷八叠球菌目(Methanosarcinales)。根据研究结果推测,土壤水分可能是导致高 寒草甸区和高寒沼泽草甸区细胞丰度和古菌群落差异的一个主要原因,高寒沼泽草甸区内产甲烷菌占优势可能与土壤高TOC含量有关。高寒沼泽草甸土壤中存在较丰富的产甲烷古菌,它们在厌 氧条件下的甲烷氧化作用也是土壤中甲烷来源之一。     

祁连山不同草地类型区土壤有机碳组份的差异

为明确高寒地区土壤有机碳库的组成及稳定程度,选择祁连山地区3种草地类型区（高寒草甸、高寒草原和高寒沼泽草甸）为研究对象,分层对0～50 cm土壤中重组、轻组组分进行分离提取,测定并分析重组有机碳（heavy fraction organic carbon,HFOC）和轻组有机碳（light fraction organic carbon,LFOC）含量.结果表明,不同草地类型对土壤HFOC和LFOC含量及其分配的影响不同,HFOC、LFOC含量在土层间均具有明显的垂直变化,呈上高下低趋势,各区域间差异明显;高寒沼泽草甸LFOC含量最高,高寒草原次之,高寒草甸最低,即不同草地类型区土壤有机碳库稳定程度大小依次为：高寒草甸>高寒草原>高寒沼泽草甸;土壤pH、含水率、TC、SOC、TN含量与C/N值与土壤HFOC、LFOC含量呈极显著相关（p<0.01）.综上,祁连山草地生态系统土壤有机碳库组成及稳定程度受草地类型、土壤理化性质及环境变量影响.     

三江源高寒草甸土壤化学计量特征及酶活性对不同退化程度的响应

土壤化学计量特征及酶活性是反映植物生长速率和养分限制的重要因子。为探究三江源高寒草甸退化过程中土壤化学计量特征及酶活性的变化特征及相互作用关系,本研究采用野外采样与室内分析相结合的方法,分析了不同退化程度(原生植被、轻度退化、中度退化、重度退化)对三江源高寒草甸的土壤有机碳(SOC)、全碳(TC)、全氮(TN)、全磷(TP)、全钾(TK)含量、pH值、土壤化学计量比、酶活性的影响及相互作用关系。结果表明：(1)随退化程度的加剧,不同土层土壤中的SOC和TN含量整体呈降低趋势,TK含量呈递增趋势,不同土层差异不显著。TP含量表现为轻度退化最高,不同土层TP含量均大于0.7 g·kg^-1,pH值随退化程度加剧变化不明显。(2)土壤C、N、P、K化学计量比整体随着退化程度的加剧呈降低趋势,其中碳氮比值变化较为稳定。(3)β-1,4-木糖苷酶(BX)、β-N-乙酰氨基葡萄糖苷酶(NAG)、酸性磷酸酶(AP)、β-纤维二糖苷酶(BCE)、β-葡萄糖苷酶(BG)五种酶活性在不同土层中均表现为轻度退化显著高于其他退化程度(P<0.05)。(4)土壤SOC、TN、TP含量及...     

青藏高原多年冻土区高寒草地生物量与环境因子关系的初步分析

以青藏高原多年冻土区3种高寒草地植被为研究对象,设置6个样地,并结合附近活动层观测场环境因子数据,定量分析生物量与环境因子的关系.结果表明,各高寒草地地下生物量对总生物量的贡献率最大,而地下生物量在0～10cm集中分布;对于总生物量和地下生物量,各因子影响程度大小次序为:土壤盐分土壤含水量空气温度,而对地上生物量,依次为土壤含水量土壤盐分空气温度;土壤温度同生物量存在负相关关系.同时,伴随多年冻土退化,活动层表层不同深度(10～50cm)土壤温度明显升高,含水量逐渐降低,土壤盐分不断增加,从而使高寒草地植被类型出现由高寒沼泽草甸、高寒草甸至高寒草原的逆向演替过程,群落总盖度及生物量均表现出明显降低的趋势.     

祁连山海北高寒湿地植物群落结构及生态特征

海北高寒湿地系沼泽型和湖泊型湿地相并存.海北高寒湿地植物种类组成较少,从湿地中央到边缘植物优势种组成不同,群落结构变化明显.中部以帕米尔苔草为主要植物建群种的沼泽草甸,边缘地带以藏嵩草为主要建群种的沼泽化草甸,从中央到边缘地带主要有25种植物组成,隶属10科20属.高寒湿地植物有较高的地上生物量(349.373 g·m^-2)和地下生物量(仅1~40 cm层次最高可达10769.301 g·m^-2),而且地下部分远高于地上部分,地下生物量从表层到深层基本均匀下降,与矮嵩草草甸和金露梅灌丛草甸区的地下生物量分布截然不同.因湿地帕米尔苔草、藏嵩草、黑褐苔草、华扁穗草等为主的植物粗纤维高,牲畜利用率下降,不论地上还是地下对土壤有机物的补给均较高,多年的积累使其海北高寒湿地有深达2~3 m的泥炭层,使湿地形成一个非常重要的碳库.在气候变暖的条件下,这些未分解或半分解的土壤有机物质(或残体)将加速分解,对大气有更多的CO₂、CH₄等温室气体的排放.     

Unity of the national and the international in the socio-cultural development of the peoples of the USSR

International unity is becoming ever stronger in this country owing to an increasing similarity in the development of the cultural environment. This comprises the provision of all the country's republics with a sufficient number of schools, theatres, and other institutions and cultural information media in accordance with the needs of the population. An important part is played by the rise in ‘the general educational level, as well as the level of professional qualifications and skills. Among all the Soviet nations and nationalities, this rise being more rapid among formerly backward peoples. Prominent among the factors of internationalization is the progressive development of the nationalities’ cultural resources, while professional culture is being increasingly brought within the reach of the masses.The implementation of the nationalities policy promotes the all-round development of all Soviet nations and nationalities, their drawing together, the upsurge of the individual capabilities of every Soviet citizen.     

Report of the restudy of the defined global stratotype of the base of the Silurian System

The Global Stratotype Section and Point （GSSP） for the base of the Silurian System was defined in 1985. Since that time, a number of researchers have suggested that this section has serious deficiencies for use as a GSSP. As a result, in 2000, the Subcommission on Silurian Stratigraphy （SSS） proposed undertaking a formal restu@ of this GSSP, which was subsequently approved by the International Commission of Stratigraphy （ICS）. The result of this restudy was the formal proposal that the current GSSP, at 1.6 m above the base of the Birkhill Shale, at Dob＇s Linn, Scotland, should be maintained as the same locality and stratigraphic level, but the bios- tratigraphical definition of the boundary should be revised. The previously defined, basal Silurian grapto- lite zone, the Parakidograptus acuminatus Zone, should be subdivided into a lower Akidograptus ascensus Zone and a higher E acuminatus Zone. The base of the A. ascensus Zone, marked by the first appearance of A. ascensus, should be regarded as the biostratigraphic mark for the base of the Silurian. This proposal has now been formally approved by the SSS and ICS, and ratified by International Union of Geological Sciences. This is the first GSSP to undergo formal restudy and redefini- tion, and the proposal also included a recommended procedure for restudy of GSSPs.     

Deviation of the major axis of the inertia ellipsoid of the Moon from the direction toward the Earth

It is known from observations that the center of mass of the Moon does not coincide with the geometric center of its figure, and the line connecting these two centers is not aligned with the direction toward the center of the Earth, instead deviating toward the Southeast. This stationary deviation of the axis of the inertia ellipsoid of the Moon to the South of the direction toward the Earth is analyzed. A system of five linear differential equations describing the physical libration of the Moon in latitude is considered, and these equations are derived using a new vector method taking into account perturbations from the Earth and partly from the Sun. The characteristic equation of this system is obtained, and all five oscillation frequencies are found. Special attention is paid to the fifth (zero) frequency, for which the solution of the latitude libration equations are stationary and represents a previously unknown additional motion of the rotational axis of theMoon in a cone with a small opening angle. In contrast to the astronomical precession of the Earth, the rotation of the angular-velocity vector is in the positive direction (counter-clockwise), with the period T ₃ = 27.32 days. On this basis, this phenomenon has been named “quasi-precession.” This quasi-precession leads to a stationary inclination of the major axis of the inertia ellipsoid of theMoon to the South (for an observer on Earth), making it possible to explain one component of the observed deviation of the center of mass of the Moon from the direction toward the Earth. The opening angle of the quasiprecession cone is approximately 0.834″.     

东濮凹陷北部沙河街组三段中亚段沉积环境分析

东濮凹陷北部沙三中亚段广泛发育盐岩和烃源岩,这两个看似不能共存的物质却在这里互层共生。该时期研究区沉积特征为多盐韵律与多层烃源岩互层共生、连续沉积,单个盐韵律厚度从几米到十几米,烃源岩有机质丰度高、类型好。平面上,两者在湖盆沉积沉降中心共生;垂向上,高有机质丰度、好干酪根类型与高盐度地层具有较好的对应关系。因而成为恢复古气候和古环境的重要研究对象。通过岩石学、古生物学以及Sr/Ba、B/Ga、(V+Ni+Mn)、Fe/Mn、Sr/Cu、Mg/Ca、V/(V+Ni)、稀土元素含量和氯同位素等方法对凹陷北部沙三中亚段的沉积环境进行研究。结果表明,凹陷北部沙三中亚段为深水沉积的还原环境,古盐度较高,达到半咸水-咸水沉积;微量元素和孢粉化石特征表明研究区沙三中亚段为温暖潮湿的环境。     

The Tendencies of the Development of the Mineral-Resources Sector at the Turn of the Century

Important tendencies in development of the world mineral-resources sector at the beginning of the 21st century were an increase in production and consumption of mineral materials differentiated by types of metals and nonmetallic mineral raw materials, by countries and regions, as well as the concentration of the production of mineral raw materials in a small number of countries, and a reduction in industrial reserves of minerals in the world economy, even at the current stage of their extraction. These tendencies should be taken into account in working out a strategy for development of the Russian mineral raw-material base.     

Causes of the famine among the rural population of the Sahelian zone of the Sudan

Taking the example of W Sudan, an analysis of the climatic incidents leading to the two recent famine disasters is made. On this natural background, the human side is investigated. Focus is directed towards the fragile economic structure of the famine-prone population groups. An early-warning system for famine in the Sahelian Zone is proposed taking grain production and storage, livestock development and the relationship between the prices of livestock and grain as major indicators.     

郯庐断裂南段研究进展与断裂性质讨论

据1：5万区域地质调查和专题研究资料，就郯庐断裂带是否南延与消失的原因，其与大别—苏鲁造山带交截形成的假位错效应，以及与中新生代沉积盆地形成演化的关系等作了新的阐述。在此基础上，讨论了郯庐断裂带是否为巨大的左行平移断层或转换断层。认为郯庐断裂带可能是在“古郯庐带”的基础上于早侏罗世重新活动、白垩纪强烈活动的地堑型枢纽断裂带。     

The Importance of the Precipitation and the Susceptibility of the Slopes for the Triggering of Landslides Along the Roads

In order to characterise the influence of the heavyrains on the observed landslides during the 1996–1997hydrological cycle, rainfall records for the last 100years are analysed from 104 stations in easternAndalusia. Regarding the amounts of rain recordedbetween October 1996 and March 1997 in the 104stations studied, 31 presented new all-time records;15 presented values that were 80–100% of thepre-1995 record; 49 stations, 80–50%; and 9stations, < 50%. A map has been devised of thesusceptibility of the materials through which thesouth-eastern Andalusian road network crosses,together with an inventory of the damage caused byinstability phenomena on banks and cuttings of theroad network during the winter of 1996–1997. Therelationships between the rainfall during the studyperiod, the damage caused to the road network and thesusceptibility of the materials affected are analysed.The results indicate that there is a clearcorrespondence between the rainfall recorded and thesusceptibility of the materials with the inventorieddamage. It is concluded that the widespread seriousdamage caused in early 1997 to the roads andsurrounding areas in the Alpujarra region and thecoast of the Province of Granada was mainly caused bythe extraordinarily heavy rains. However, considerablyless damage was observed where the susceptibility ofthe terrain is low, thus highlighting the extremeusefulness of terrain-susceptibility maps for riskprevention and territorial planning.