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为探究洱海湖滨区环境因子与蜻蜓物种多样性之间的关系,2014年5月至2017年5月对洱海10个样点进行实地调查,记录植物20科46种,共采集蜻蜓11科22属28种1448个体,并对环境因子与蜻蜓多样性进行相关性分析.结果表明蜻蜓成虫多样性与植被丰富度、湿生植被覆盖度、挺水植被覆盖度和沉水植被覆盖度均呈正相关,与浮水植物覆盖度和人为干扰程度呈负相关;稚虫多样性与湖底底质和水体溶解氧呈正相关,并对结果进行了讨论.研究结果给洱海蜻蜓栖息地的保护及湖滨缓冲带生态修复提供了有益的参考和数据支持. 相似文献
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Ritta Niinioja Anna-Liisa Holopainen Liisa Lepist Anita Rm Jouko Turkka 《Limnologica》2004,34(1-2):154
Lake Pyhäjärvi, on the border between Finland and Russia in Karelia, is a very valuable clear-water lake of the Lobelia type. It belongs to the European Union's Natura 2000 programme in Finland, and has been included in regional and national monitoring programmes since the 1960s. The main monitoring station is situated near the outlet of the lake. Deterioration of its water quality was suspected already in the 1980s because of decreasing Secchi depths (transparency) and increasing chlorophyll a.The occurrence of algal blooms on the lakeshores is monitored weekly during each summer at one site on Lake Pyhäjärvi (site 1). This is a part of nationwide intensive algae monitoring programme organised by the environmental authorities together with voluntary observers at some 270 lake sites in Finland since 1998. Since 1997, Secchi depth observations have been carried out by volunteers biweekly or monthly at 17 sites on the lake. In the vicinity of one of these transparency observation sites (station 100), intensive monitoring of algae has been carried out. At this lakeshore monitoring site 69 algal observations were made, ten of which recorded algal blooms during the study period 1998–2002. The observed algal blooms were caused by algae of the Anabaena species, mainly by Anabaena lemmermannii. At Lake Pyhäjärvi the number of algal bloom observations received from the public have decreased from the 1990s to the 2000s. The range of Secchi disc transparency was 5.0–8.4 m with a mean value of 6.2 m at station 100 and 4.3–7.7 m (mean 6.1 m) at the main monitoring station 2 during the open water periods in 1998–2002. During this study period, the maximum values at site 100 seem to have increased slightly, which might indicate some improvement in the water quality due to decreased point source loading.We conclude that the intensive algal monitoring results of 5 years at the lakeshore site and the transparency results — both compiled by trained volunteers — reflect an improvement in the state of Lake Pyhäjärvi in Karelia. This conclusion is in accordance with the long-term water quality and short-core studies of sedimentary diatoms in Lake Pyhäjärvi. We suggest that the intensive algal observations and transparency measurements are both suitable methods for the monitoring of lakeshores and lakes, and that both are suitable for voluntary monitoring. We found public participation a good tool for monitoring lakes and lakeshores. 相似文献
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对沉积颗粒大小、形态特征的量化和解释,是沉积动力条件分析和古地理重建的重要内容之一.图像法作为粒度分析的标准,长期受制于样本量小、效率低等困难.基于动态图像法的新型粒度粒形分析系统可在几分钟内获取多达n×107个颗粒的形状和大小信息,为沉积环境重建和动力条件分析提供了新的机会.本文基于两组样品(青藏高原的湖滩砂和黄河中游的河流砂)的动态图像粒度粒形数据,定量分析和对比了湖滩与河流两种环境沉积颗粒的粒度、粒形特征及其异同.结果表明,样品组成颗粒的球度与均值粒度之间整体上存在明显的反相关,球度-粒度曲线可大致划分为斜率不等的三段:占据颗粒绝大多数的中段(C.S.)球度适中,斜率最小;细端(F.T.)球度大,斜率也大;粗端(C.T)球度小,斜率小且不稳定.结合天然沉积颗粒的形状和密度特征,本文认为这些不同斜率的段落可能源于沉积颗粒密度效应和形状效应导致的粒度分异.对比研究表明,湖滩砂与河流砂在粒形-粒度曲线形态与分段特征方面均存在明显差异,两组样品在不同粒形参数(球度—长宽比—凹凸度)三角图和不同球度分段所对应颗粒体积百分比(C.T.-C.S.-F.T.)三角图中均能完全分离.这些事实表明基于动态图像分析的粒度粒形分析可望成为一种潜在的第四纪环境重建工具,在环境研究中有助于对天然沉积物物源特征以及风化、侵蚀、搬运和堆积过程的认识和理解. 相似文献
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合肥市滨湖新区地质调查与城市地质研究 总被引：2，自引：0，他引：2
根据大量调查资料,总结了合肥滨湖新区的地质特点,划分了与城市建设密切有关的工程地质分区,可为新区规划提供科学的地质科学依据. 相似文献
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三角洲砂体是含油气盆地勘探的最主要储集体类型之一,湖相三角洲类型基本均为河控型三角洲。明确河控三角洲砂体发育机制、迁移规律、分布特征、组合结构等规律不仅具有科学意义,而且对于油气勘探具有重要的指导意义。影响河控三角洲砂体的因素较多,宏观上构造活动控制了盆地的类型、形成、演化、沉积底型形态、坡度及物源等。在构造相对稳定时期,河控三角洲砂体主要受3种因素控制:物源供屑能力(简称物源),沉积底型坡度(简称坡度)和湖岸线位置(简称岸线)。物源供屑能力控制了砂体规模,体现在粒度、砂体厚度及范围;底型坡度控制了砂体宽厚比,表现在砂体前积层角度大小及三角洲形状;湖岸线河口处是沉积物主要卸载区,其位置及迁移幅度控制了砂体位置及连续性。3种因素不同的变化组合形成了不同特征的三角洲砂体分布模式。 相似文献
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Quaternary sedimentology of the Rose Creek fan delta, Walker Lake, Nevada, USA, and implications to fan-delta facies models 总被引：1，自引：0，他引：1
The 3·2 km long Rose Creek fan delta of west‐central Nevada is prograding from an active rift margin into the 32 m deep Walker Lake. A case study of the forms, processes and facies of this fan delta reveals that the proximal and medial zones mainly are of sub‐aerial origin, and the distal zone is of lacustrine origin. Pebbly to bouldery rock‐avalanche mounds >100 m thick (Facies A) and muddy to bouldery debris flow levées 0·5 to 2·0 m thick (Facies B) dominate the proximal zone, whereas mostly matrix‐supported cobbly pebbly debris flow lobes 0·1 to 1·0 m thick (Facies C) typify the medial zone. Surficial pebble lags and gully fills (Facies D) are widespread in both zones but, in exposures, comprise only partings or lenticles between debris flow units. The distal fan delta mainly consists of lakeshore to lake‐bottom tracts formed by extensive wave reworking of debris flow facies. Nearshore deposits include erosional cobbly boulder lag beaches (Facies E), pebbly constructional beaches attached at headcuts or on barrier spits (Facies F), pebbly upper shoreface (Facies G) and sandy lower shoreface (Facies H) tracts positioned lakeward of the beach, and pebbly landward‐dipping foresets (Facies I) and backshore‐pond sand and mud (Facies J) present landward of the spits. Erosional lag beaches fringe the windward north side of the fan‐delta front, attached constructional beaches characterize the central zone, and southward‐elongating barrier spits typify the leeward south side, extending from the zone of greatest projection of the fan delta into the lake. Shoreline facies asymmetry results from largely unidirectional longshore drift caused by high fetch to the north and minimal fetch to the south, combined with the arcuate shape of the fan‐delta front. The spits overlie a platform deposited below common wave base consisting of south‐east‐trending cones of pebbly Gilbert foresets (Facies K) and sandy toesets (Facies L). Typically slumped silt and mud (Facies M) fringe both this platform and lower shoreface sand in deeper water. This case demonstrates facies types and patterns that are inconsistent with the widely promoted fan‐delta facies model having a front consisting of an apron of radially directed Gilbert foresets deposited where sub‐aerial flows enter the lake. The Rose Creek fan‐delta front instead features a sharp contact between sub‐aerial and lakeshore facies formed where waves erode, sort and redistribute heterogeneous debris flow sediment into the various shallow‐to‐deep lake facies. Gilbert foresets are present only in the lee of the fan delta where sediment moving by longshore drift reaches the brink of the spit front. This facies scenario results from the infrequency of fan‐building events versus nearly constant wind‐induced waves, a scenario that, in contrast to the popular Gilbert model, probably is the norm for fan deltas. The level of Walker Lake, and thus the position of wave reworking on the Rose Creek fan delta, fluctuated over a range of ～157 m during the last 18 kyr, producing complex interfingering between sub‐aerial and lakeshore facies across a 1700 m wide radial belt, typifying a wave‐modified, freestand lacustrine fan delta. 相似文献
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伊犁盆地含煤系地层沉积相特征及其与层间氧化带砂岩型铀矿成矿关系 总被引：16，自引：1，他引：16
本文从研究伊犁盆地不同地段含煤系地层岩性变化特征入手，提出冲积扇快速入湖的扇三角洲沉积相模式，并讨论了４个沉积亚相，即冲积扇、扇前辫状河、滨湖三角洲、湖沼相的沉积相特征及其空间展布规律，研究了含煤系沉积相与层间氧化带砂岩型铀矿的成矿关系，指出了滨湖三角洲相砂体是寻找层间氧化带砂岩型铀矿的主要部位。 相似文献
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随着发达地区经济社会的快速发展,水污染物排放量急剧增加,甚至超出区域水环境容量,致使水环境不断恶化,并成为制约区域经济社会发展的重要因素.本文综合考虑水环境容量供给能力和需求状况两方面要素,以流域为基本评价单元,采用综合分区技术和矩阵向量模型,构建水环境容量总量指标分配方法,并以无锡市区为例提出水环境容量的多情景配置方案.在此基础上,引入基尼系数方法测度不同方案的公平性,据此进行情景方案的优选.总体上,中心城区及东北部地区配置较大的环境容量,位于太湖上游的西部和西北部地区以及望虞河沿线地区环境容量供给能力较低,配置较少的环境容量.研究结果可为协调区域产业发展与水环境关系、制定差别化的产业准入政策提供科学依据. 相似文献
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CAUSES AND COUNTERMEASURES FOR CHAOHU LAKESHORE COLLAPSE 总被引：3，自引：0，他引：3
GAOChao WANGXin-yuan YANGZe-dong LUYing-cheng HEHui 《中国地理科学(英文版)》2005,15(1):88-93
1INTRODUCTIONChaohu Lake (30°25′28"-31°43′28"N, 117°16′54"-117°51′46"E) is located in the center of Anhui Provin-ce, and is one of the five biggest freshwater lakes inChina. The lakeshore′s collapse is one of the main envi-ronmental hazards of th 相似文献
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