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1.
高寒草甸土壤微生物功能多样性对积雪变化的响应 总被引：2，自引：2，他引：0
积雪是高寒地区不可忽视的生态因子,不仅直接影响土壤温度、水分,而且间接影响土壤微生物群落组成和多样性。为研究高寒草甸生态系统中土壤微生物对积雪变化的响应,于2013年11月至2014年7月在青藏高原东缘红原县高寒草甸,通过人工堆积的方法建立4个不同积雪梯度,以自然积雪量为对照（CK）,2倍于自然积雪量（S1）、3倍于自然积雪量（S2）、4倍于自然积雪量（S3）。运用Biolog-Eco板法研究不同积雪梯度下土壤微生物功能多样性,并测定积雪变化对土壤温度和土壤养分的影响。结果表明：积雪期内,0~10 cm土层土壤温度随着积雪量的增加而降低,而10~20 cm土层随积雪量增加先降低后升高。增加积雪量处理后0~10 cm土层全磷（TP）、有机碳（SOC）显著增加（P<0.05）;而10~20 cm土层仅S3下全氮（TN）、TP、SOC增加。每孔平均变化率值（Average well color development,AWCD）在0~10 cm土层表现为CK > S2 > S1 > S3,而10~20 cm表现为S2 > S1 > CK > S3。在0~10 cm土层,S3处理显著降低了土壤微生物多样性McIntosh指数、Shannon-Wiener指数和Pielou指数（P<0.05）; 10~20 cm土层,S1和S2处理下多样性指数显著增加（P<0.05）。主成分分析显示：氨基酸类和酚酸类是微生物利用的主要碳源类型。相关性分析表明：多样性指数与TP、SOC、碳氮比（C/N）显著负相关（P<0.05）,氨基酸类碳源与TP、C/N显著负相关（P<0.05）。因此,冬季积雪一定程度上影响着土壤温度和土壤养分,进而影响高寒草甸土壤微生物群落功能多样性。 相似文献
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3.
V. N. Makarov 《Geochemistry International》2016,54(11):1005-1010
The paper presents data on the distribution of tritium, a hydrogen radioactive isotope, in the snow cover of mid-taiga landscapes in central Yakutia. Regional tritium escape to the atmosphere in the late 20th century and its accumulation in the snow cover resulted from regional atmospheric transfer and corresponded to the concentration of this isotope in the snow cover at the South Pole. Tritium concentration in the snow cover had almost tripled by 2013. Tritium concentration in the snow cover is correlated with the human population of the settlement zone. The long-term anthropogenic contamination in the area is caused first of all by atmospheric fallouts of radioactive products of the 2011 Fukushima accident. 相似文献
4.
从第三极到北极： 热喀斯特及其对碳循环影响研究进展 总被引：2，自引：2，他引：0
北半球多年冻土区储存着大量的土壤有机碳, 气候变暖加剧了多年冻土退化, 多年冻土退化最明显的特征是热喀斯特。热喀斯特会直接导致活动层及多年冻土层土壤有机质暴露, 并改变水文、 植被和土壤生物环境条件, 对生态系统碳循环具有重要影响。热喀斯特对碳循环的影响是评估多年冻土碳循环和气候变化关系不确定性的关键问题之一。然而, 在气候变暖背景下热喀斯特地貌的发育及其对碳循环影响有多大, 目前对这个问题仍然缺乏足够的认识。通过综合比较第三极和北极热喀斯特相关研究, 分析了第三极和北极地区热喀斯特地貌特征及其变化趋势, 阐述了热喀斯特对植被演替、 土壤碳损失和生态系统温室气体排放过程的影响, 并提出了未来热喀斯特研究可能遇到的挑战。认识热喀斯特碳循环过程, 是评估气候变化对多年冻土碳循环影响的关键环节, 有助于加强多年冻土区生态系统碳循环与气候变暖之间反馈关系的认知。 相似文献
5.
Marcia Phillips 《Natural Hazards》2006,39(3):353-379
Snow-supporting avalanche defence structures are increasingly being built at high altitudes in potential permafrost areas.
Special construction methods and guidelines have been developed to ensure a minimal stability of the structures, which have
a vital role in the protection of underlying settlements and transport infrastructure against snow avalanches. If the avalanche
slopes are located on ice-rich permafrost terrain, as is the case in a steep avalanche gully above Pontresina (Eastern Swiss
Alps), other means of protection must be used – such as deflection or retention dams – as construction on ice-rich sediments
can be very problematic. Experimental snow-supporting structures were built in 1997 in order to test different types of structures
and their foundations, to develop specially adapted construction methods and to monitor the long-term behaviour of the structures
in moderately creeping frozen ground with volumetric ice contents under 20%. Snow-nets were found to be the most suitable
type of protection against avalanches in this type of permafrost terrain due to their deformability and because they are well
adapted to rock fall. The structures do not improve slope stability but contribute towards maintaining permafrost as they
delay snow melt by modifying the spatial and temporal distribution of the snow cover. The results of the project described
have led to a better understanding of permafrost-related avalanche defence problems. 相似文献
6.
在气候变化的背景下, 寒区灌丛与积雪的相互关系成为寒区水文循环研究的重要环节. 综述近几十年来寒区灌丛-积雪相互关系的国内外研究现状, 并对未来研究提出了展望. 寒区灌丛过去几十年来覆盖面积和生物量等呈现增加趋势, 灌丛的增加可截留积雪, 改变积雪重分布, 影响积雪消融过程; 积雪可增加灌丛区地温, 制约灌丛区融雪时空变化过程, 影响寒区灌丛的生理生态过程. 灌丛与积雪同为寒区自然生态系统和环境的重要组成部分, 二者相互作用使地面太阳辐射和地表水分分配过程复杂化, 从而间接地影响寒区冻土环境变化. 最后, 指出了未来研究需要重点关注的几个问题: 寒区灌丛区积雪分布的精确估计; 灌丛-积雪-冻土连续体的研究; 耦合灌丛-积雪作用的寒区水文模型的构建. 相似文献
7.
低分子有机酸是对流层大气的重要组成成分,采用离子色谱法测定了贵阳市大气降水中的有机酸浓度.结果表明,气象因素是影响贵阳市大气降水中有机酸浓度的重要因素.其中,降雨系统对雨水中有机酸浓度的影响显著.大气有机酸主要是在降雨初期进入降水并被清除的,降雨初期对大气有机酸的清除量占总清除量的50%-70%.随着降雨的进行,雨水中的有机酸浓度逐渐降低,降雨后期略有升高,大降雨量对雨水中有机酸浓度起稀释的作用.雷雨和台风雨中有机酸浓度明显偏低,降雪中有机酸浓度也远远低于雨水中有机酸浓度,暗示贵阳市雨水中有机酸主要是在云下过程进入降水的.天气因素是通过影响大气中有机酸浓度进而影响雨水中有机酸浓度的,如气温对雨水中有机酸浓度的影响远没有降雨量明显.不同来源气团雨水中有机酸浓度明显不同,其中以北面方向气团降水中有机酸浓度最高,与我国内陆大气污染较重有关,而源于海洋方向的东南气团雨水中有机酸浓度最低. 相似文献
8.
青藏高原北麓河地区荒漠草原土壤细菌对热融滑塌的响应 总被引：2，自引：1，他引：1
多年冻土区地下冰融化造成的热融滑塌会对土壤理化性质产生一系列影响,进而影响微生物群落结构,但目前热融滑塌对荒漠草原区土壤微生物的影响还不清楚。利用Illumina测序方法,以青藏高原北麓河多年冻土区发生热融滑塌的荒漠草原为研究对象,对3种微地貌（对照区、滑塌区、沉降区）下的土壤细菌展开研究,分析了细菌群落结构及其与环境因子间的关系。结果显示滑塌区和沉降区有机碳含量显著低于对照区,滑塌区土壤含水量最高;放线菌门、变形菌门、绿弯菌门和酸杆菌门是3种微地貌下的优势菌群,对照区细菌群落丰富度显著低于滑塌区。Mantel检验表明,细菌群落结构与土壤理化性质间无显著相关性;非度量多维尺度分析（NMDS）表明,微生物群落结构在3种微地貌下显著不同。研究结果表明,在荒漠草原区,热融滑塌会改变土壤理化性质,影响细菌特定门的微生物相对丰度,但对门水平的整体群落结构影响不显著。 相似文献
9.
新疆天山西部巩乃斯河谷积雪与森林/草地 覆盖条件下季节冻土特征分析 总被引：1，自引：0，他引：1
不同的覆盖条件下,季节冻土的特征会存在差异。为了分析积雪与森林/草地覆盖条件下季节冻土的特征,在新疆天山西部巩乃斯河上游的中国科学院天山积雪雪崩研究站的实验场地监测了森林-积雪,草地-积雪,以及草地覆盖条件下季节冻土的冻结深度,并对有无积雪覆盖条件下季节冻土发育过程中的土壤温度和土壤含水量进行了跟踪测量。结果表明：森林-积雪覆盖条件下季节冻土的冻结深度最浅,草地-积雪覆盖条件下次之,草地覆盖条件下最深。积雪的存在可以改变季节冻土的冻结深度,还会影响土壤温度和土壤含水量变化。在季节冻土的发育阶段,积雪的隔热作用使得有积雪覆盖条件下土壤温度和土壤含水量较高;在积雪消融阶段,由于积雪融水的补给,土壤含水量也相应地增加,积雪消失后由于蒸发的存在导致土壤含水量减少。 相似文献
10.
I. A. Nemirovskaya 《Geochemistry International》2009,47(4):393-404
This paper reports data on the concentrations of organic compounds (organic carbon, Corg; lipids; aliphatic hydrocarbons, AHCs; and polycyclic 0aromatic hydrocarbons, PAHs) in snow, ice, and subice waters from the mouth of the Severnaya Dvina River (2005–2007) and Kandalaksha Gulf (Chupa Bay, 2004) at the end of winter. It was established that organic compounds are accumulated in the snow and upper ice layer near the town of Archangelsk. The distribution of molecular markers indicates that pollution was mainly caused by local fallouts. In Chupa Bay, organic compounds are concentrated in the lower ice layers, which is typical of the Arctic snow-ice cover. The high contents of organic compounds in the snow-ice cover of the White Sea are caused by the pollution of its air and water during the winter season. 相似文献
11.
积雪对多年冻土活动层和近地表的热状态具有重要影响。然而,积雪对祁连山区黑河上游地区多年冻土热状态的影响机制尚不清楚,迫切需要可靠的野外观测数据进行定量研究。基于两个典型野外监测站点2012—2019年观测数据,分析积雪对表面能量平衡、5 cm地表热通量及活动层热状态的影响。结果表明：厚度约21 cm的积雪在秋冬季对活动层具有保温作用;2013—2018年,俄博岭（EB）和野牛沟（PT1）监测场,活动层厚度分别为61~86 cm和159~164 cm,平均活动层厚度分别为74.2 cm和162.1 cm。受积雪影响,相隔两年（2015—2017年）的活动层厚度变化达25 cm。定量分析了祁连山积雪对多年冻土热状态的影响,为未来祁连山相关研究提供重要资料。 相似文献
12.
The Hydrograph model (a distributed process-based model) was applied to the simulation of soil freeze-thaw and runoff processes, to assess the viability of the model approach and the influence of specific environmental factors in a permafrost environment. Three mountainous permafrost watersheds were studied, at the Kolyma Water Balance Station in north-eastern Russia. The watersheds include rocky talus, mountainous tundra and moist larch-forest landscape regimes, and they were modelled at daily time-steps for the period 1971–1984. Simulated results of soil freeze-thaw depth and runoff showed reasonable agreement with observed values. This study reveals and mathematically describes the dependence of surface and subsurface flow on thawing depth and landscape characteristics. Process analysis and modelling in permafrost regions, including ungauged basins, is suggested, with observable properties of landscapes being used as model parameters, combined with an appropriate level of physically based conceptualization. 相似文献
13.
东北冻土区积雪深度时空变化遥感分析 总被引：5，自引：5，他引：0
积雪作为冰冻圈的重要组成部分,对地面有保温作用,在消融时又吸收热量降低地面温度,影响冻土发育,对气候的变化十分敏感。利用微波遥感数据1979-2014年逐日中国雪深长时间序列数据集,采用GIS空间分析和地学统计方法,分析了东北冻土区积雪深度的时空变化规律及其异常变化。结果表明,东北冻土区多年平均雪深为2.92 cm,年平均雪深最高值出现在岛状多年冻土区,最低值出现在季节冻土区。东北冻土区年平均积雪深度变化以减少为主,占区域面积的39.77%,减少速率为0.07 cm·（10a）-1。东北冻土区年平均积雪深度在1986年发生突变,开始出现减少的趋势,这与气温突变年份较为吻合。受地形和气温变化影响,年平均积雪深度减少的敏感区域主要发生在岛状多年冻土区。气温是影响东北冻土区年平均积雪深度变化最主要的因素,降水量、风速、湿度、日照时数对积雪深度均有影响。季节冻土区积雪深度对气候的敏感性要大于多年冻土区。 相似文献
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Results from the study of experimental plots at Hubbard Brook, New Hampshire for the years 1987, 1988, 1993, 1994, 1995, and 1996 show that the water draining from under a plot planted with pine trees exhibits its highest alkalinity during the year at about the time of spring snowmelt. This high alkalinity is believed to be due to buildup during the winter under a snow cover. The soil solutions are protected from acidic precipitation by the snow, and the natural process of the reaction of organic acids and carbonic acid with minerals and exchange complexes to form dissolved HCO3
– (and organic anions) proceeds with an increase in alkalinity through the winter. When the snow melts the acidic meltwater mixes with, neutralizes and displaces the water previously occupying the soil interstices. This leads to a decided drop in alkalinity of the drainage water. The alkalinity buildup under the pine plot was found to be two to ten times greater than under a similar plot containing no higher plants. This strongly emphasizes the important role of plants, in their ability to produce organic acids and high levels of CO2, in accelerating the weathering of silicate minerals. 相似文献
16.
黑河流域陆地—大气相互作用研究的几点思考 总被引：4，自引：2，他引：2
陆地和大气之间是相互作用、相互影响的,不仅陆面分布与地表过程对大气变化有着响应过程,而且陆面物理过程、地表特征分布对大气过程也有着重要影响。我国西北地区地形分布极不均匀,是水资源变化和气候变化的敏感区与脆弱地区。这里,由于海拔高度起伏造就了以水为主线的上游山区冰雪、冻土—中游森林、绿洲—下游戈壁荒漠的多个自然景观带共存的内陆河流域,是开展陆—气相互作用研究的理想场所。文章集中黑河流域水循环过程、冰雪/冻土与大气相互作用、降水异质性、人类活动影响以及尺度等问题,阐述了流域研究现状以及研究热点,指出发挥各学科优势,将大尺度的大气过程与中间尺度和小尺度的陆面水文/生态过程结合,建立流域尺度大气—水文—生态过程真正的双向耦合模式,不仅研究气候变化对陆面水文、生态的影响,同时探讨陆面小尺度过程对大气的反馈机理,探索流域尺度的水循环过程和驱动机理,为水资源合理利用提供理论基础。 相似文献
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森林凋落物的分解对于维持生态系统物质循环和养分平衡具有重要意义,并受到不同积雪厚度下冻融格局的影响。冻融期（包括冻结过程期、完全冻结期、融化过程期）是冻土区凋落物分解的重要时期,该时期分解的凋落物量约占全年分解总量的一半。积雪减少通常会导致土壤温度降低、冻融循环次数增加,进而影响凋落物分解。通过综述近10年来积雪变化对我国森林凋落物分解影响的研究成果发现,积雪厚度减少在冻融期通常会抑制凋落物质量损失、碳元素释放和纤维素降解,生长季则起到促进作用,从全年来看多数表现为抑制作用。因此,冻融作用造成凋落物的物理破坏,对其分解的促进作用主要发生在后续生长季。积雪厚度减少在冻融期通常抑制氮元素释放,生长季和全年则无明显规律;磷元素和木质素目前研究还存在很大差异。最后,进一步阐述了积雪变化对凋落物分解影响研究存在的问题及未来研究发展方向。 相似文献
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兴安岭-贝加尔（兴-贝）型多年冻土处于欧亚大陆高纬度多年冻土南缘,对气候变化和人类活动较为敏感。为了研究多年冻土变化规律以及预测其未来变化趋势,从环境因素对多年冻土的影响以及多年冻土与环境的相互作用两个方面出发,围绕地带性因素（纬度、高度、经度）和非地带因素（气温、植被、降水、积雪等）两大类环境因素的变化对多年冻土分布与发育的影响,分析了兴-贝型多年冻土的变化和发展趋势,总结认为：气温、植被、降水、积雪等环境因素共同作用,改变了土层水热状况,促使区域内大范围多年冻土经历了显著退化;退化程度存在区域差异,多年冻土南界附近退化程度最为显著。基于兴-贝型多年冻土的特殊性,提出了建立冻土和寒区环境监测机制并及时采取适应性和整治性措施保护和修复区域环境的建议。 相似文献
19.
Stefanie Cable Bo Elberling Aart Kroon 《Boreas: An International Journal of Quaternary Research》2018,47(2):423-442
This paper presents the history and cryostratigraphy of the upper permafrost in the High‐Arctic Adventdalen Valley, central Svalbard. Nineteen frozen sediment cores, up to 10.7 m long, obtained at five periglacial landforms, were analysed for cryostructures, ice, carbon and solute contents, and grain‐size distribution, and were 14C‐ and OSL‐dated. Spatial variability in ice and carbon contents is closely related to the sedimentary history and mode of permafrost aggradation. In the valley bottom, saline epigenetic permafrost with pore ice down to depths of 10.7 m depth formed in deltaic sediments since the mid‐Holocene; cryopegs were encountered below 6 m. In the top 1 to 5 m, syngenetic and quasi‐syngenetic permafrost with microlenticular, lenticular, suspended and organic‐matrix cryostructures developed due to loess and alluvial sedimentation since the colder late Holocene, which resulted in the burial of organic material. At the transition between deltaic sediments and loess, massive ice bodies occurred. A pingo developed where the deltaic sediments reached the surface. On hillslopes, suspended cryostructure on solifluction sheets indicates quasi‐syngenetic permafrost aggradation; lobes, in contrast, were ice‐poor. Suspended cryostructure in eluvial deposits reflects epigenetic or quasi‐syngenetic permafrost formation on a weathered bedrock plateau. Landform‐scale spatial variations in ground ice and carbon relate to variations in slope, sedimentation rate, moisture conditions and stratigraphy. Although the study reveals close links between Holocene landscape evolution and permafrost history, our results emphasize a large uncertainty in using terrain surface indicators to infer ground‐ice contents and upscale from core to landform scale in mountainous permafrost landscapes. 相似文献
20.
Shojae Ghias Masoumeh Therrien René Molson John Lemieux Jean-Michel 《Hydrogeology Journal》2017,25(3):657-673
Numerical simulations of groundwater flow and heat transport are used to provide insight into the interaction between shallow groundwater flow and thermal dynamics related to permafrost thaw and thaw settlement at the Iqaluit Airport taxiway, Nunavut, Canada. A conceptual model is first developed for the site and a corresponding two-dimensional numerical model is calibrated to the observed ground temperatures. Future climate-warming impacts on the thermal regime and flow system are then simulated based on climate scenarios proposed by the Intergovernmental Panel on Climate Change (IPCC). Under climate warming, surface snow cover is identified as the leading factor affecting permafrost degradation, including its role in increasing the sensitivity of permafrost degradation to changes in various hydrogeological factors. In this case, advective heat transport plays a relatively minor, but non-negligible, role compared to conductive heat transport, due to the significant extent of low-permeability soil close to surface. Conductive heat transport, which is strongly affected by the surface snow layer, controls the release of unfrozen water and the depth of the active layer as well as the magnitude of thaw settlement and frost heave. Under the warmest climate-warming scenario with an average annual temperature increase of 3.23 °C for the period of 2011–2100, the simulations suggest that the maximum depth of the active layer will increase from 2 m in 2012 to 8.8 m in 2100 and, over the same time period, thaw settlement along the airport taxiway will increase from 0.11 m to at least 0.17 m.
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