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1.
利用电镜扫描的方法分析了南极阿德雷岛Y2湖企鹅粪土沉积层中石英砂微形貌的特征,发现在企鹅粪含量高的沉积层中石英砂表面具有明显的碗状溶蚀坑等化学溶蚀特征,这一溶蚀特征在Y2湖企鹅粪含量低的沉积层和研究区的其他未受企鹅粪影响的沉积环境中均未明显出现。为了揭示这一特殊化学溶蚀现象的作用机制,根据Y2湖企鹅粪土沉积层自然沉积环境,通过条件实验确定在实验室内使用酸性较高的氟溶液(1mol.L-1HF溶液)对石英砂进行溶蚀实验,通过对比分析发现,实验室模拟条件下可以得到与企鹅粪土沉积层中石英砂相近的表面微形貌特征,这表明它们是在相似的过程中形成的。企鹅粪土沉积层酸性高氟环境中可能存在的HF酸化学溶蚀作用是形成企鹅粪土层中石英砂表面特有溶蚀坑的主要原因。在南极特殊的自然条件下碗状溶蚀坑与企鹅粪之间存在一定的因果关系,从而使石英砂的表面微形貌分析成为南极企鹅生态研究的一种新的辅助手段。 相似文献
2.
2006/2007夏季对南极长城站地区的企鹅种群数量、分布及其繁殖行为进行了生态学调查与研究,共记录到5种企鹅:白眉企鹅、阿德利企鹅、纹颊企鹅、王企鹅和帝企鹅,前3种企鹅在本地区繁殖,后2种为本区旅鸟。阿德雷岛是本地区最重要的企鹅繁殖地,2006/2007南极夏季阿德雷岛上繁殖的企鹅约为9724只,繁殖期后的企鹅总数约为17220只,繁殖成功率为0.40—1.41只/对。通过与历史资料对比,初步分析了近年来在本地区繁殖的企鹅数量与种群结构的变化趋势及其与气候、环境、人类活动的关系。 相似文献
3.
反射光谱技术:研究南极企鹅古生态演化的一种新方法 总被引：2，自引：0，他引：2
为探求快速、廉价、无损和同步的光谱技术在南极生态环境研究中的可能性,本文利用南极阿德雷岛的四根企鹅粪土沉积柱样品的反射光谱,通过逐步多元线性回归和主成分回归两种数学运算方法,建立了反射光谱数据与企鹅粪九种标型元素浓度之间的关系,并探讨了南极企鹅粪土沉积物光谱数据的古生态意义。结果表明:南极粪土沉积样品反射率光谱与企鹅粪九种标型元素(P、Ca、Cu、F、Ba、S、Zn、Sr、Se)含量之间存在良好的相关性,预测值与实测值之间的相关系数R都达到了0.9以上,在深度剖面上预测浓度与实测浓度具有非常一致的变化趋势;南极粪土沉积物光谱数据包含有明确的古生态变化信息,可利用主成分分析快速恢复历史时期企鹅数量演化过程。本研究结果为在偏远的南极地区开展古生态环境研究提供了一种新的快捷方法和技术途径。 相似文献
4.
在中国第22次南极考察(2005/2006)期间,采集了东南极戴维斯站区加德纳岛(GardnerIsland)上一根含企鹅粪的沉积泥芯。分析测试了该沉积物、新鲜企鹅粪和当地基岩中部分化学元素的含量。对元素进行聚类分析并结合对比新鲜企鹅粪、基岩中的部分元素含量特征后得出,该粪土沉积的生物标型元素组合包括P、Se、F、S、As、Cu和Sr等7种元素。这与西南极阿德雷岛企鹅粪土层的生物标型元素组合是基本一致的。在此基础上,对东、西南极企鹅粪土层的生物标型元素进行了优选,得出东南极优选生物标型元素为P和Se,西南极则为F、P和S。这为探讨东南极企鹅数量变化及东、西南极企鹅数量变化的对比研究打下了基础。 相似文献
5.
对南极阿德雷岛企鹅栖息地粪土层进行210Pb测年,同时采用气相色谱-电子捕获检测器(GC-ECD)内标定量法测定了企鹅栖息地粪土混合地层和企鹅蛋卵中有机氯污染物含量,粪土混合地层中有机氯污染物最高浓度:表层PCBs为0.92ng/g,HCHs为0.42ng/g,DDTs在0.70ng/g,与非栖息地相比较,研究结果显示,通过鸟类活动的粪土混合地层(营巢和粪便)输入PCBs和OCPs含量比无鸟类生命途径的土壤相对要高。企鹅蛋卵样∑PCB在0.4-10.2ng/g,∑DDT2.4-10.3ng/g,HCB0.1-9.4ng/g,∑HCH0.1-0.5ng/g,总积蓄水平依次为:∑PCB>∑DDT>HCB>∑HCH。 相似文献
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7.
拜尔斯半岛位于南极利文斯顿岛最西部,是南设得兰群岛中最大的无冰区。对采自拜尔斯半岛的一根长55 cm的企鹅粪土沉积柱P1进行了元素和同位素地球化学分析。通过对沉积物C/N、有机质来源和δ15N的分析,发现P1沉积剖面中有机质主要来源于企鹅粪。利用富集系数、相关性分析、主成分分析等统计分析方法,识别出该沉积剖面中P、F、Cu、Hg、As、S六种元素具有共同的来源,与企鹅粪的输入密切相关,并且这些元素与TOC和δ15N显著正相关,说明沉积剖面中这些元素含量主要受控于企鹅粪的输入程度。通过与长城站区阿德雷岛、东南极戴维斯站加德纳岛企鹅粪土沉积物的标型元素特征比较,发现上述三个地区的标型元素组合大体上一致,反映了整个南极地区企鹅粪土沉积物生物标型元素组合的共性。研究结果为进一步恢复该地区的企鹅种群数量演化,及其对气候变化的响应提供了可能。 相似文献
8.
本文分析了南极阿德雷岛Y2湖企鹅粪土沉积层的有机地球化学组成与分布。结果表明企鹅粪土沉积层中正构烷烃以C23为主峰,主要来源于冻土湖沼苔藓植物,样品中高含量的烯烃说明其有机质保存良好。醇类以高浓度的植醇和胆甾烷醇为主,胆甾烷醇和胆甾醇浓度曲线一致,并与企鹅粪土层中的无机元素标型组合的曲线相似,可以作为灵敏的企鹅数量指示剂。酸类组分中以C18饱和脂肪酸为主,在南极低温的环境下,C18∶2酸浓度很低,在很多层次中未检测到,可能是因为Y2沉积物中C18酸以及C18∶2酸主要受企鹅粪影响,而非植被影响。同时在酸性组分中也发现高浓度的胆甾酸。Y2湖中的甾类标志物,甾烯、甾醇、胆甾酸均以C27结构为主,组成单一,低浓度的甾烯和高浓度的甾醇,胆甾酸说明甾类化合物主要受企鹅粪便影响,甾醇和胆甾酸保存良好。综合Y2湖的生物标志物的性质,该沉积物有机质保存良好,主要来源于企鹅粪。 相似文献
9.
川西米亚罗亚高山地区云杉林群落结构分析 总被引：5，自引：0，他引：5
岷江上游杂谷脑河流域米亚罗地区是典型的亚高山针叶林分布区域,也是国家实施天然林保护工程的重点地区。本文分析了该区云杉原始林的种类组成、层片结构、云杉径级和高度分布格局。调查样地共有37种植物,隶属于22科30个属,其中主要以温带成分的小叶型、草质、中高位芽植物为主。群落层次结构复杂,可分为乔木层、灌木层、草本层和苔藓层四个层次,乔木层郁闭度一般为0．6～0．8,云杉为乔木层的绝对优势树种,占70％以上,平均树高在17m左右,胸径在8～25cm之间。云杉高度主要集中在18～22m和8～12m两个区间,分别占云杉总个体数54．4％和25．0％;而胸径主要集中在25cm和30cm两个径级,占总数的52．6％,二者都表现为主林层和次林层的集中分布格局。与云杉人工林群落相比较,原始林层次结构复杂、物种丰富度高,生态功能强,可将其群落结构作为诊断亚高山针叶林生态系统健康的指标之一。 相似文献
10.
龙胜里骆杉木人工林群落的降水截留和养分淋溶归还 总被引：5，自引：0，他引：5
龙胜里骆杉木人工林乔木层林冠年截留率为１５．６％，林下植物层的年截留率为２１．７％（占林外降水量的１８．３％）。降水强度是影响截留量（率）大小的主要因素；同时，林冠的枝叶生长和林下植物盖度的变化对截留量（率）大小也有一定影响，林冠截留量（率）与林外降水量间存在密切的对数关系，而林下植物截留量（率）与林冠降水量或林外降水量之间的函数关系随不同季节而变化，冬春季为幂函数，夏秋季为直线或对数关系，这主要 相似文献
11.
The summer diet of Little Owls (Athene noctua) in Minqin Desert Experimental Research Station of northwestern China was analysed. A total of 293 individuals representing seven species of rodents, one bird, three reptiles, two families of invertebrates and unidentified invertebrates were identified in 113 pellets and 29 prey remains collected during June and July of 2005. By frequency, invertebrates constituted 77.5% of the diet, mammals 17.8%, reptiles 3.8% and birds 1.0%. In term of biomass consumption, mammals comprised 93.7% of the diet, invertebrates 3.9%, birds 1.9% and reptiles 1.1%. The results suggested that the Little Owls were active at day and night and fed mainly on rodents and beetles related to the desert habitats. 相似文献
12.
Internal oscillations in the Earth's fluid core 总被引：4，自引：0，他引：4
Susan Friedlander 《Geophysical Journal International》1985,80(2):345-361
13.
Toshihiro Yoshimura Rei Nakashima Atsushi Suzuki Noriko Tomioka Hodaka Kawahata 《Journal of Paleolimnology》2010,43(3):437-448
We present oxygen and carbon isotope ratios and the morphological structure of the cultured freshwater pearl mussel (Hyriopsis sp., Unionidae) shell and pearl. The number of first-order fluctuations of δ18O of the outer shell layer along the maximum growth axis was consistent with the number of cultured years. The dominant factor
controlling annual δ18O fluctuations was water temperature with a minor contribution from the variation in δ18O of ambient water, especially during the rainy season. The δ13C values were approximately constant throughout the life of the mussel, suggesting that the contributions of body size to
δ13C of the shell were minor. We observed nine distinct disturbance rings on the outer surface of the shell. Five rings coincided
with the five winter peaks of the δ18O profile, indicating winter growth cessation below approximately 10°C, probably because of either inactive growth at low
water temperatures or reproduction. Summer disturbance rings were not observed in all years. Moreover, some summer rings showed
discontinuity in the inner structure. These findings suggest that summer growth cessation may be caused by occasional events
such as heavy rains, as the decrease of dissolved oxygen concentration. The δ18O profile and shell structures indicated that shell aragonite was precipitated at close to equilibrium conditions with respect
to the oxygen isotope composition of the ambient water. Hyriopsis sp. shells can potentially be used for reconstruction of past hydrologic conditions. The δ18O of a pearl indicated that calcification occurred over a temperature range of at least 13–23°C. The optimal temperature for
pearl calcification in this species is lower than that for marine pearl calcification. 相似文献
14.
Goro Komatsu John W. Olsen Jens Orm Gaetano Di Achille David A. Kring Takafumi Matsui 《Geomorphology》2006,74(1-4):164-180
The Tsenkher structure, in the Gobi-Altai region of Mongolia, was studied using a wide array of remote sensing data and field observations. The structure has a shallow, 3.6 km wide, central depression bordered by a near-circular ridge (putative crater rim) with breaches to the northwest. The central depression is obliterated partially by fluvial infill through these breaches. Outside the ridge, the western side is a rugged terrain, but the eastern half is characterized by a concentric outer ridge that occurs at about one radius distance from the inner ridge. Although intrusion, salt tectonics and maar crater hypotheses cannot be completely ruled out, its morphology strongly implies an impact origin for the Tsenkher structure. If of impact origin, it has a well-preserved morphology and its position in the basin fills indicates that the formation may have occurred relatively recently, sometime during the late Tertiary or Quaternary. The outer ridge morphology is similar to rampart craters on Mars, whose formation has been attributed to fluidization of a water-rich target layer and ejecta materials, or to atmospheric entrainment and deposition of ejected materials. However, other hypotheses including erosional remnant of ejecta blanket, erosional scarp of structural rim uplift, multi-ring or deeply eroded crater rim of a peak-ring crater are also possible at this stage. A complex fluvial and probable lacustrine history is envisaged within the Tsenkher structure. The structure is also associated with archaeology, including Paleolithic and Bronze Age remains. 相似文献
15.
粗糙床面风廓线的转折特征及其物理意义 总被引：4，自引：3，他引：1
为了进一步认识粗糙床面空气动力学粗糙度的物理意义,理解空气动力学粗糙度对动量传递和跃移起动的影响机制,从风洞试验测定的粗糙床面风廓线转折特征入手,分析了粗糙床面的空气动力学性质并提出了内边界层动量传递及近壁区沙粒起动的可能机制。结果表明,细高粗糙元（方向比率在4~20之间）和孔隙粗糙元（孔隙度在0.15~0.75）风廓线呈现4个转折段,对应的湍流垂直分层为近壁区-尾涡层（Z≤0.15H~0.5H）、内边界层-尾涡层过渡层（0.15H≤Z≤0.75H）、内边界层（0.3H~0.75H≤Z≤1.2H~6H）和内边界层与外边界层过渡层等。粗矮粗糙元（粗糙元的方向比率在0.4~1.25之间）风廓线存在几个转折段,对应气流垂直分层为近壁区-尾涡层（Z≤1H~1.5H）和内边界层（1H~1.5H≤Z≤7H~35H）等。细高粗糙元和孔隙粗糙元覆盖21组床面（侧影盖度在0.007~0.50,粗糙元的高度在10~100 mm）的内边界层内空气动力学粗糙度在0.07~30.74 mm之间,比内边界层以上或以下过渡层的空气动力学粗糙度高几个数量级到数倍;内边界层摩阻风速的0.50~1.66 m\5s-1之间,是内边界层以下过渡层的1.5~10倍、内边界层以上过渡层的摩阻风速的1.1~2.8倍。内边界层的空气动力学粗糙度和摩阻风速分别代表了粗糙床面对气流阻力特征和湍流切应力。内边界层以下过渡层湍流切应力与粗糙元之间光滑地表所受切应力关系不大,而近壁层切应力与光滑地表所受切应力直接相关。近壁层猝发过程上抛运动和内边界层湍流猝发过程下扫运动耦合关系是内边界层的一部分动量传递到近壁区并导致沙粒起动的可能机制。 相似文献
16.
广州市社区出行低碳指数格局及其影响因素的空间异质性 总被引：4，自引：1，他引：3
通过构建社区出行低碳指数（CTLCI）模型,对广州市社区出行低碳指数的空间格局及其差异特征进行了分析,并利用全局回归（OLS）模型和地理加权回归（GWR）模型对社区出行低碳指数的影响因素以及其间关系的空间异质性进行了研究。结果表明,广州市社区出行低碳指数由中心城区向外逐渐递增,呈明显的圈层结构。内圈层的社区出行低碳指数内部差异最小,中间过渡圈层的最大。社区人口密度对社区出行低碳指数的影响以正向作用为主,公共交通供给水平和路网密集程度对社区出行低碳指数的影响以负向作用为主,且它们的影响作用具有空间异质性。具体指出了在不同地域空间内社区人口密度、公共交通供给水平和路网密集程度对社区出行低碳指数在影响程度和作用方向上的差异,为减少广州城市交通碳排放、针对不同空间制定有效的低碳政策和构建低碳城市空间结构提供了科学依据。 相似文献
17.
对南极Amanda湾帝企鹅的卵进行了生态生物学观测与相应的统计分析。结果显示,帝企鹅卵为典型的卵形卵,平均长、短径分别为121.3mm和83.8mm;平均卵容量409.3ml(322.6-506.4ml),卵的平均壳厚为1.11mm(0.94-1.23mm)。帝企鹅和南方巨鹱、白眉企鹅以及灰贼鸥等南极海鸟的卵相比较,卵的形态大小与容量成正比,同时,容量较大的卵具有较厚的卵壳,以增强对卵的保护。这些海鸟卵的生态生物学特征,包括保护色的有无、卵容量的大小,以及卵壳厚度等特征参数,是这些海鸟种的明显特征,并与亲鸟在繁殖期的窝卵数以及孵化习性相协调,以达到对南极环境的适应与生存。 相似文献
18.
In addition to socio-economic factors, major landforms may affect the city structure and urban form. Here we show that landforms have significant effects on the city shape and street patterns of the fast-growing Iranian cities of Dezful （a river） and Khorramabad （moun- tains and valleys）, but no clear effects on the cities of Yazd and Nain. Also, where the street orientation is peaked, the Gibbs/Shannon entropy （a measure of dispersion or spread） is low, but increases as the distribution becomes more uniform because of landform constraints. The streets in the old inner parts of all the cities are, on average, shorter and denser （more streets per unit area） than the streets of the newer outer parts. The entropies of the outer parts are also greater than those of the inner parts, implying that the street-length distribution gradually becomes more dispersed or spread as the city expands. All these cities have been fast growing in the past decades, with the newer outer parts expanding rapidly. As shown here, the rapidly formed outer parts （with greater dispersion in street patterns） have significantly different textures from those of the older inner parts, indicating different functionality and growth processes. These quantitative methods for street-network analysis can be used worldwide, particularly for analysing the effects of landforms on city shape and texture. 相似文献
19.
In addition to socio-economic factors, major landforms may affect the city structure and urban form. Here we show that landforms have significant effects on the city shape and street patterns of the fast-growing Iranian cities of Dezful(a river) and Khorramabad(mountains and valleys), but no clear effects on the cities of Yazd and Nain. Also, where the street orientation is peaked, the Gibbs/Shannon entropy(a measure of dispersion or spread) is low, but increases as the distribution becomes more uniform because of landform constraints. The streets in the old inner parts of all the cities are, on average, shorter and denser(more streets per unit area) than the streets of the newer outer parts. The entropies of the outer parts are also greater than those of the inner parts, implying that the street-length distribution gradually becomes more dispersed or spread as the city expands. All these cities have been fast growing in the past decades, with the newer outer parts expanding rapidly. As shown here, the rapidly formed outer parts(with greater dispersion in street patterns) have significantly different textures from those of the older inner parts, indicating different functionality and growth processes. These quantitative methods for street-network analysis can be used worldwide, particularly for analysing the effects of landforms on city shape and texture. 相似文献
20.
In addition to socio-economic factors,major landforms may affect the city structure and urban form. Here we show that landforms have significant effects on the city shape and street patterns of the fast-growing Iranian cities of Dezful (a river) and Khorramabad (mountains and valleys),but no clear effects on the cities of Yazd and Nain. Also,where the street orientation is peaked,the Gibbs/Shannon entropy (a measure of dispersion or spread) is low,but increases as the distribution becomes more uniform because of landform constraints. The streets in the old inner parts of all the cities are,on average,shorter and denser (more streets per unit area) than the streets of the newer outer parts. The entropies of the outer parts are also greater than those of the inner parts,implying that the street-length distribution gradually becomes more dispersed or spread as the city expands. All these cities have been fast growing in the past decades,with the newer outer parts expanding rapidly. As shown here,the rapidly formed outer parts (with greater dispersion in street patterns) have significantly different textures from those of the older inner parts,indicating different functionality and growth processes. These quantitative methods for street-network analysis can be used worldwide,particularly for analysing the effects of landforms on city shape and texture. 相似文献