近10年艾比湖湿地不同植物群落土壤水分 盐分 养分变化特征

为研究新疆准噶尔盆地艾比湖湿地不同植物群落近10年土壤水盐及养分的动态变化,以环湖1周160km范围内的典型植被梭梭-柽柳、梭梭、胡杨、芦苇群落为研究对象,分析其在2006和2015年土壤含水量、盐分含量、pH值和有机质含量的变化和空间分布特征。结果表明:(1)近10年艾比湖湿地不同植物群落土壤有机质含量和含水量明显下降且整体水平较低,二者分别下降了24.65%~48%和5.41%~20.16%;土壤含盐量、pH值分别上升81.92%~128.74%和2.99%~4.21%,土壤盐碱程度加强。(2)通过土壤水分-盐分-养分空间分布分析显示,各群落近10年土壤盐渍化增加、养分降低程度大小表现为梭梭-柽柳群落胡杨群落梭梭群落芦苇群落,其中梭梭-柽柳群落土壤达到重度盐化水平,有机质降到6级,而其他群落土壤均为中度盐化,有机质为4级,但芦苇群落土壤退化程度较小。研究发现,近10年艾比湖湿地不同植物群落土壤养分不断下降、水分含量降低、盐渍化程度加剧,土壤处于退化状态;土壤质地、降水和气温暖干化是不同植物群落下土壤退化程度差异的基础,人口、耕地面积和农业用水等人类活动使各群落土壤退化程度的差异更加显著。     

盐渍化条件下土壤团聚体及其有机碳研究进展

土壤团聚体是土壤结构的基本单元,对改善土壤结构和增加土壤固碳具有重要作用。盐渍化导致的特殊土壤性质,如高盐分离子(主要为Na⁺)浓度、低有机质含量和较差的微生物条件等因素,对团聚体的形成和稳定产生障碍作用,因此探讨盐渍化土壤团聚体特征更具有重要性和特殊性。滨海湿地和内陆盐渍化沼泽湿地是盐渍化生态系统的重要组成部分。本文系统整理和总结了国内外盐渍化土壤团聚体及其有机碳的研究进展,并对上述两种盐渍化湿地生态系统中土壤团聚体研究进行了综述。土壤有机无机改良剂添加、耕作方式、植被类型、秸秆还田以及微咸水灌溉等农业措施对盐渍化土壤团聚体及其有机碳形成和稳定具有积极影响。最后提出了目前盐渍化土壤团聚体及其有机碳研究存在的问题和不足,并对未来的研究方向和热点进行了展望,为全面了解盐渍化土壤团聚体研究的最新成果和发展方向提供参考。     

Illumina高通量测序揭示艾比湖湿地6种盐生植物根际土壤真菌群落组成及多样性

[目的] 通过研究新疆艾比湖湿地不同盐生植物根际土壤真菌的多样性和群落结构,为艾比湖湿地退化恢复工作和真菌深入研究提供理论支持。[方法] 利用高通量测序技术对真菌扩增子ITS1区进行测定,从而分析艾比湖湿地6种盐生植物根际土壤真菌群落多样性,并结合相关土壤理化因子分析环境与真菌群落多样性和丰富度的关联。[结果] 艾比湖湿地6种盐生植物根际土壤真菌群落多样性及丰富度存在差异,碱蓬根际土壤真菌多样性最高,芦苇根际土壤真菌群落丰富度最高。真菌群落组成分析表明,土壤样品中真菌菌落主要隶属于子囊菌门（Ascomycota）和担子菌门（Basidiomycota）,其中子囊菌门为主要优势菌门;链格孢霉属（Alternaria）是6种植物共有的优势菌属,但是其在不同植物之间的丰度存在差异,在戟叶鹅绒藤中的丰度最高,在准噶尔大戟中的丰度最低。pH与真菌多样性呈显著负相关,全磷（TP）与真菌群落丰富度呈显著正相关,pH、电导率（EC）和有机质（OM）对优势菌属的影响最大。[结论] 艾比湖湿地6种盐生植物根际土壤真菌群落组成及多样性具有显著差异,碱蓬和芦苇根际土壤真菌的多样性和丰度高于其他植物,子囊菌门和链格孢霉属是艾比湖湿地的主要土壤真菌门属。研究结果可为艾比湖湿地的生态修复提供理论指导。     

不同时期艾比湖湿地盐角草群落土壤固氮微生物的多样性分析

【目的】研究新疆艾比湖湿地不同季节盐角草根际和非根际土壤固氮微生物的多样性和丰富度与环境因子的相关性,以期探究在荒漠化和盐渍化不断严重的艾比湖湿地中随着季节变化的固氮微生物群落对恢复生态功能起到的潜在作用,为后续的湿地保护和退化恢复工作提供理论支持和数据基础。【方法】应用Illumina HiSeq PE250测序技术,分析6个土壤样本固氮微生物的多样性,结合相关的理化因子并利用RDA分析法探究土壤理化性质和固氮微生物菌落结构及丰富度的相关性。【结果】艾比湖湿地盐角草植物根际土壤的固氮微生物多样性高于非根际土壤,7月的土壤固氮微生物多样性高于10月和4月的土壤。土杆菌属(Geobacter)、假单胞菌属(Pseudomonas)、固氮菌属(Azotobacter)和慢生根瘤菌属(Bradyrhizobium)等为盐角草根际和非根际土壤中的共同优势菌属。这些固氮微生物优势菌属隶属于变形菌门(Proteobacteria)和蓝藻门(Cyanobacteria),且相对丰富度占比为85%和10%,其余各菌门共占比较少,仅为5%。土壤中固氮微生物的优势菌群与碱解氮(AN)、全氮(TN)、速效钾(AK)和有效磷(TP)呈显著相关。【结论】随着时间的推移土壤样本中固氮微生物的多样性和群落结构也发了改变,同一时期植物根际与非根际土壤中固氮微生物的群落结构并不相同。土壤的环境因子与固氮细菌的群落结构和丰富度的相关性研究可以为艾比湖湿地的退化恢复提供数据基础和理论支持。     

艾比湖湿地土壤有机碳及储量空间分布特征

土壤碳储量的研究是全球碳循环研究的热点,土壤碳库的变化对全球气候变暖、维护生态平衡都有着重要的意义。新疆的艾比湖湿地是干旱区典型的盐湖湿地,为探明该湿地有机碳特性及储量,选择艾比湖湿地1m深度的土壤作为研究对象,测试有机碳含量后,对艾比湖湿地土壤有机碳特性进行分析并分层定量测算有机碳储量,结果显示:(1)艾比湖湿地土壤有机碳整体偏低,随土层加深,含量依次递减的规律比较显著。湿地7种不同植被覆盖类型的土壤有机碳含量垂直空间变异性差异明显,其中荒漠河岸林、盐化草甸、小乔木荒漠大多属于强变异,而其它植被覆盖的土壤类型多属于中等变异。(2)艾比湖湿地7种不同植被类型土壤有机碳含量在相同土层的分布特征为:有机碳集中分布在浅表层(0—20 cm),从40 cm以下变幅缓慢,分布较为均匀。不同植被类型土壤有机碳在不同土层的分配比例差异比较明显,但表层(0—20 cm)大多占到30%以上。(3)艾比湖湿地土壤有机碳储量排序依次为小乔木荒漠盐化草甸干涸湖底灌木荒漠盐生灌丛荒漠河岸林寒湿性针叶林。湿地有机碳蓄积总量为7086862.83 kgC。上述研究结果可为新疆干旱区湿地生态系统恢复、保护与科学管理提供科技支撑。     

艾比湖湿地盐节木土壤固氮微生物群落结构和丰度的环境异质性特点

【背景】新疆艾比湖湿地国家自然保护区作为国内最典型的温带干旱区湿地荒漠生态系统,对于富集生物多样性、平衡生态环境等方面存在着非凡的意义。目前关于艾比湖湿地根际与非根际土壤固氮微生物群落结构和丰度的相关研究还未见报道。【目的】通过分析新疆艾比湖湿地盐节木根际和非根际土壤固氮菌nifH基因的群落结构和丰度的环境异质性特点,及探讨微生物群落对国内极端干旱区脆弱敏感的艾比湖湿地生态系统循环过程中的作用,为改善荒漠化的艾比湖湿地环境提供理论依据。【方法】采用构建克隆文库和q-PCR的方法,并利用冗余分析法(Redundant analysis,RDA)探究土壤理化性质与固氮微生物群落结构及丰度的相关性。【结果】艾比湖湿地盐节木非根际土壤中nifH的多样性高于根际土壤,盐节木根际土壤的nifH序列优势种属主要为固氮根瘤菌属(Azorhizobium)和脱硫弧菌属(Desulfovibrio);非根际土壤的nifH序列优势种属主要是固氮弧菌属(Azoarcus)、太阳杆菌属(Heliobacteriummodesticaldum)和脱硫弧菌属(Desulfovibrio)。盐节木根际土壤nifH数量为4.08×104copies/g,盐节木非根际土壤中nifH的数量为5.52×103copies/g,根际土壤nifH的丰度高于非根际土壤。相关性分析显示,根际土壤的优势类群和丰度与硝态氮(NO3--N)、速效氮、总钾、含水量等因子显著相关,非根际土壤的优势类群和丰度与硝态氮(NO3--N)、速效氮、总磷、总钾、总氮呈显著相关。【结论】在盐节木根际土壤中nifH的丰度高于非根际土壤,而多样性则低于非根际土壤,而且硝态氮(NO3--N)、速效氮、总磷可能会影响固氮微生物的群落结构和丰度,这些特点为湖泊湿地的退化恢复提供理论和数据基础。     

中国特有种艾比湖沙拐枣(Calligonum ebinuricum)不同生境的土壤特征分析

对中国特有植物艾比湖沙拐枣(Calligonum ebinuricum)生境的土壤特征进行了分析。结果显示,艾比湖沙拐枣生境土壤粒径范围集中在中砂(0.25~0.5 mm)和粗砂(0.5~1.0 mm),为粗砂土;土壤的pH值在7.98~10.24之间,平均值为8.78,整体呈碱性;电导率在0.09~1.41 ms.cm-1之间;总盐含量为0.525~8.400 g.kg-1,有些地段存在盐渍化;阳离子中Ca2+含量最多,阴离子中SO42-含量最多;土壤养分含量很低,有机质含量在0.829~1.190 g.kg-1,集中在1 g.kg-1左右;各样地间土壤盐分含量特征变异系数较大,土壤机械组成和土壤养分变异系数较小。经过SPSS聚类分析和主成分分析,将艾比湖沙拐枣(C.ebinuricum)群落的土壤生境划分为3种类型:硫酸盐型盐渍化风沙土生境、强碱性风沙土生境和普通风沙土生境。普通风沙土生境是其分布的主要生境。     

大漠盐湖——艾比湖国家级自然保护区

正在距离新疆阿拉山口边境口岸不远的盆地区域,有一处名叫艾比湖湿地的国家级自然保护区,范围包括精河县、博乐市和阿拉山口市,东西长约100公里,南北宽约70公里,总面积267085公顷。保护区始建于2000年,2007年经国务院批准晋升为国家级,以湿地及珍稀动植物资源为主要保护对象。虽然从类型上看,艾比湖是一个内陆湿地类型的保护区,但是实际     

准噶尔盆地植被与土壤盐渍化关联性变化趋势分析

准噶尔盆地作为北疆地区主要的气候单元其环境变化会影响北疆地区整体的的生态环境变化。植被作为衡量区域生态环境的重要指标直接反映了准噶尔盆地的生态状况,近年来受到全球气候变化的影响准噶尔盆地地区气候格局发生改变,盆地相比于往年降水和气温明显升高,这种改变影响了盆地的植被变化同时也会在部分地区诱发土壤盐渍化灾害。土壤盐渍化是我国西北地区常见的导致植被退化的因素,其生成原因与地形和气候因素有关。为了探究准噶尔盆地植被变化与土壤盐渍化的关联性,基于2002-2019年生长季MOD09A1遥感影像数据,利用最大值合成法、Mann-Kendall趋势分析,Hurst趋势分析法、相关性分析等方法对准噶尔盆地植被和土壤盐渍化变化趋势以及两者的关联性进行了分析。结果表明,受区域降水和气温升高的影响,近20年来准噶尔盆地生长季植被整体呈增加趋势,各季节增加区域面积占比为63.50%-90.93%,平均为77.98%。土壤盐渍化呈减少趋势,各季减少区域面积占比为46.50%-86.78%,平均为70.68%。在地形低洼、排水不畅的区域土壤盐渍化程度加重,植被因盐分胁迫导致衰退,植被减少及巨大的蒸发降水比使得该地区土壤进一步变干,湿度降低。关联性分析结果表明各季植被与土壤盐渍化的变化中呈显著负相关的区域面积占比为37.36%-57.83%,平均为51.75%。Hurst趋势预测结果表明,当前植被和土壤盐渍化两者呈显著性变化的区域未来预测与当前变化方向相同,两者呈一般性变化的区域未来预测与当前相反。研究有助于在全球气候变化背景下了解准噶尔盆地近年来生态环境变化,结果为区域生态环境的可持续发展提供参考。     

基于MODIS与Landsat 8的艾比湖湿地旱情时空变化及其影响因素分析

对干旱区艾比湖湿地旱情进行多源遥感监测,分析干旱对艾比湖湿地的生态安全与农业生产的影响,为水资源合理配置与干旱预警提供依据。选用2013年5月到2016年5月的MODIS温度和植被指数产品数据反演TVDI指数,并构建二维特征空间,分析土壤水分的时空分布特征,结果表明:TVDI可以有效地反演土壤水分,且精度较高;通过分析,艾比湖湿地土壤水分格局呈现由"极湿润-湿润-正常"面积减少,"干旱-极干旱"面积增加的趋势;在此基础上分析了影响艾比湖干旱变化的影响因素,近年来随着温度升高,风速与蒸发量增加,降水量减少,使艾比湖湿地旱情急剧恶化。利用多源遥感能很好的实现大面积、长时间、高精度的旱情监测,在四年间艾比湖湿地的旱情有所加剧,湖水面积与冰川萎缩变化较为严重,可见艾比湖湿地旱情情况较为不乐观,需加强水资源管理,开展艾比湖旱情监测对于干旱区湖泊生态有重要的理论与实际意义。     

Size fractions of dust and amount of associated metals on leaf surface and inner wax of 15 plant species at Beijing roadside

To provide more insight into the removal ability of urban air dust and associated metals by plant leaves, and thus guide urban green planning to improve air quality, 15 plant species leaves collected from Beijing roadside were analyzed for size fractions of leaf surface dust (SD) and inner wax dust (WD). Seven associated metals Cd, Cr, Cu, Fe, Mn, Pb and Zn were also measured. Metal Accumulation Index (MAI) was calculated for different species leaves at various dust sizes and soluble forms, respectively. Cluster analysis was used for the plant species and correlations between dust and metal concentrations and for inter-metal concentrations were calculated for both surface and inner wax dust. Mean leaf total dust TD (SD?+?WD), SD and WD were measured as 1159, 817 and 342?mg m^?2, respectively, with the highest values observed all in Euonymus japonicus. Most species leaves collected larger ratios of SD than WD except Salix babylonica and Robinia pseudoacacia. While SD was presented at all particle size fractions for all plants, nearly all species leaves collected higher proportions of WD >10?µm. Mean metal levels of leaf TD of all species ranged from high to low as Fe?>?Cr?>?Zn?>?Pb?>?Cu?>?Mn?>?Cd, but with different orders for individual species. Metals were observed in all sizes of SD/WD, although the size distributions were various for certain metals. Intercorrelations of metal concentrations in leaf SD/WD were positively significant except Pb, which may have different emission sources. Species Prunus cerasifera f. atropurpurea, Syringa oblata, Malus micromalu, Koelreuteria paniculata and Robinia pseudoacacia may possess better overall metal collection ability due to their relatively higher MAI values, but species Euonymus japonicus, Malus micromalu, Ligustrum x vicaryi and Koelreuteria paniculata were identified as the best choices in removing air dust based on cluster analysis and suggested to be planted at heavy trafficked road site for air quality improvement.     

北京市26种落叶阔叶绿化树种的滞尘能力

为筛选适用于北京市的具有优良滞尘能力的绿化物种, 提高城市植被滞尘效应, 选取北京市园林绿化应用最广泛的26种落叶阔叶树种, 应用质量差值法, 于2014年夏季对不同树种单位叶面积滞尘量进行测定, 计算单叶滞尘量与单株滞尘量, 并对树种滞尘能力进行了相应的聚类分析。结果表明: 不同树种间滞尘能力存在较大差异, 选择不同的滞尘量计量单位, 树种滞尘量排序会相应地发生变化。对26种北京市常用落叶阔叶树种从叶片、植株与综合滞尘能力三个方面的聚类分析均可得到相应的分类, 各类别代表不同级别的滞尘能力水平。研究分析认为, 植物滞尘能力与其叶表特征、滞尘方式、株型结构、整株叶量及所处环境含尘量等密切相关, 评价树种滞尘能力时应进行综合考虑。     

A comparison of worker exposure to inhalable and total dust, inorganic arsenic, and borates using two types of particulate sampling assemblies in a borate mining and processing facility

This study describes a comparison of worker exposure to total and inhalable dust, inorganic As, and borates using two types of particulate sampling assemblies as part of a comprehensive industrial hygiene evaluation in a borate mining and processing facility. Employees were segmented into similar exposure groups (SEG) based on work location within the facility, job classification, and type of chemical agent. Approximately 10% of the employees from each SEG wore two personal sampling devices simultaneously for the purpose of collecting total and inhalable particulate fractions using a closed face, 37-mm mixed cellulose ester matched-weight filters (MMW), and Institute of Occupational Medicine (IOM) sampling assembly. Sample results indicated that the IOM concentrations were consistently higher than the corresponding MMW concentrations for all three agents. An analysis was performed to investigate a relationship between MMW and IOM. The data revealed correlation coefficient values of 0.72, 0.82, and 0.84 for total dust (n = 197), inorganic As (n = 137), and borates (n = 194), respectively. These positive correlation coefficients indicate that the IOM and MMW measurements are consistent with each other, and can be used for predicting exposure levels. The total dust and borate large mean ratios should be considered in developing inhalable fraction-based regulatory standards.     

北京市8种常绿阔叶树种滞尘能力

为筛选适用于北京地区的具有优良滞尘能力的常绿阔叶型绿化树种,提高城市植被滞尘能力,选取北京地区园林绿化应用广泛的8种常绿(含半常绿)阔叶绿化树种,应用洗脱-质量差值法,于2014年冬、春季节对其单位叶面积滞尘量进行测定,计算单叶滞尘量和单株滞尘量,并对树种综合滞尘能力进行聚类分析.结果表明: 小叶黄杨、冬青卫矛、小叶女贞、金叶女贞、胶东卫矛、箬竹、早园竹和黄槽竹8种主要常绿(含半常绿)阔叶树种的滞尘能力存在较大差异,冬青卫矛具有最大的单位叶面积与单株滞尘能力,为1.36 g·m^-2和59.63 g·plant^-1,而箬竹的单叶滞尘能力最强(1.62 mg·leaf^-1).选择不同的滞尘量计量单位,树种滞尘量排序会发生变化.对8种常绿(含半常绿)阔叶树种做基于多指标综合滞尘能力的聚类分析可得到相应的分类,各类别代表不同级别的综合滞尘能力水平.其中,冬青卫矛、早园竹的综合滞尘能力较优良,而小叶黄杨、金叶女贞和黄槽竹的综合滞尘能力较弱.     

Early Inner Solar System Impactors: Physical Properties of Comet Nuclei and Dust Particles Revisited

During the epoch of early bombardment, terrestrial planets have been heavily impacted by cometary nuclei and cometary dust particles progressively injected in the interplanetary medium. Stardust and Deep Impact missions confirm that the nuclei are porous, loosely consolidated objects, with densities below 1,000 kg m⁻³, and that they often release small fragments of ices and dust. Recent numerical simulations of the light scattering properties of cometary dust particles indicate that they are highly porous, most likely fractal, and rich in absorbing organics compounds (with a mixture ratio of e.g. 33 to 60% in mass for comet Hale–Bopp). Taking into account the fact that porous structures survive more easily than compact ones during atmospheric entry, such results reinforce the scenario of the early terrestrial planets enrichment – in organics needed for life to originate – by comets. *Title of paper or poster *Presented at: National Workshop on Astrobiology: Search for Life in the Solar System, Capri, Italy, 26 to 28 October, 2005.     

Initial results for urban metal distributions in house dusts of Syracuse, New York, USA

A program of house dust sample collection and analysis has begun in Syracuse, New York, USA, in order to determine the feasibility of a geography-based exposure assessment for urban metals. The sampling program, and the protocols it employs, is described for two different types of wipe media, Ghost Wipes and Whatman Filters. Preliminary results show that strong spatial patterns of floor dust loading (mg dust per square foot) can be observed for data aggregated at a spatial scale of about 1600 m (-2.5 km2). Floor dust metal concentrations were similar to those found in other urban environments, with some regional variation. The median floor dust Pb concentration was -108 mg ·kg-1 for this initial data set of -264 sampled residential locations, and varied from 50 to 1100 mg Pb ·kg-1.     

植物叶片对沙尘的短时间生理生态反应

通过对在北京分布普遍的包括行道树,果树,林木,庄稼等的22种植物对模拟的沙尘在短时间的生理生态指标变化测定,表明沙尘在瞬时内确实影响各种植物叶片的生理生态过程,5种植物的净光合速率降低超过35％,但是银杏（Ginkgo biloba L.)的净光合速率增加超过57％,12个物种的呼吸速度显增加,但是苹果（Malus pumila Mill.)(M.communis D C.)和黄栌（Cotinus coggygria(L.)Scop.)的呼吸速率显降低,另外8个种变化不大。5个种的蒸腾速度显增加,9个种蒸腾速率显降低,美国梧桐（Platanus occidentalis L.)有较大的附尘力。还对3个种柿（Diospyros kaki L.f.),银杏和毛白杨（Populus tomentosa Carr.)在沙尘覆盖2h后测定生理生态指标。本研究表明在沙尘源附近种植欧州白榆（Ulmus laevis Pall.),苹果,柿和银杏等比较适合阻挡沙尘还有利于当地经济,而在离沙尘源较远的城市（如北京)真有较大附尘力的植物有利于净化空气。     

Initial results for urban metal distributions in house dusts of Syracuse, New York, USA

A program of house dust sample collection and analysis has begun in Syracuse,New York, USA, in order to determine the feasibility of a geography-based exposure assessment for urban metals. The sampling program, and the protocols it employs, is described for two different types of wipe media, Ghost Wipes and Whatman Filters. Preliminary results show that strong spatial patterns of floor dust loading (mg dust per square foot) can be observed for data aggregated at a spatial scale of about 1600 m (～2.5 kin2). Floor dust metal concentrations were similar to those found in other urban environments, with some regional variation. The median floor dust Pb concentration was ～108 mg· kg-1 for this initial data set of ～264 sampled residential locations, and varied from 50 to 1100 mg Pb · kg-1.     

Groups and Sources of Yeasts in House Dust

House dust contains bacteria, mycelial fungi, microarthropods, and yeasts. House dust samples collected in 25 apartments in Moscow and the Moscow region were found to contain yeasts belonging to the genera Candida, Cryptococcus, Debaryomyces, Rhodotorula, Sporobolomyces, and Trichosporon. The most frequently encountered microorganisms were typical epiphytic yeasts, such as Cryptococcus diffluens and Rhodotorula mucilaginosa, which are capable of long-term preservation in an inactive state. The direct source of epiphytic yeasts occurring in the house dust might be indoor plants, which were contaminated with these yeasts, albeit to a lesser degree than outdoor plants. Along with the typical epiphytic yeasts, the house dust contained the opportunistic yeast pathogens Candida catenulata, C. guillermondii, C. haemulonii, C. rugosa, and C. tropicalis, which are known as the causal agents of candidiases. We failed to reveal any correlation between the abundance of particular yeast species in the house dust, residential characteristics, and the atopic dermatitis of the inhabitants.     

Optimisation of a screening procedure for house dust mite numbers in carpets and preliminary application to buildings

The relative performances of the mobility and heat escape methods for measuring house dust mite numbers in carpet has been evaluated. The optimum method was found to be the mobility method for 24 hours at ambient temperatures which exhibited a mite collection efficiency of approximately 30%. Measurements in three dwellings showed that the method should be applied to carpet at several locations in the living room and/or bedrooms as a general sampling procedure, or adjacent to loungeroom seating to determine the worst case scenario. Carpets using different types of fibre within the same dwelling should be assessed separately. For the limited number of dwellings investigated, wool carpets were found to exhibit higher mite numbers than nylon carpets, even when the former had been insect-resist treated. No house dust mites were found in the wool carpets of an office building which was mechanically ventilated and heated and achieved low indoor humidities in winter.