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嘉陵江下游硅藻群落结构及物种多样性研究   总被引:7,自引:0,他引:7       下载免费PDF全文
于2006年11月, 2007年2月、5月和8月, 分别采集嘉陵江下游8个采样点藻类样品, 分析其硅藻群落结构及物种多样性, 并利用物种多样性指数及硅藻商等对水质进行了生物学评价。结果表明: (1)共发现89种硅藻, 硅藻细胞密度变幅为0.57×104—4.51×104 ind/L, 总平均2.31×104 ind/L; 多样性指数值变幅为0.72—3.12, 总平均2.20; 均匀度指数值变幅为0.15—0.52, 总平均0.36; 硅藻商变幅为0.66—9.48, 总平均3.24。 (2)硅藻群落结构呈现出季节和水平分布上的变化。在季节变化上, 物种丰富度、细胞密度及多样性指数等以温度较低的春(5月)、秋(11月)两季最高, 而以夏季(8月)最低。在水平分布上, 从上游到下游, 硅藻群落结构呈现出物种丰富度、多样性指数值逐渐减小, 而细胞密度和硅藻商逐渐增加的趋势。(3)嘉陵江下游水质总体为β-中污水体。其中位于城市上游的云门、沙溪、温塘峡、井口水质较好, 为微污或β-中污水体, 而位于城区及下游的合川、毛背沱、磁器口和朝天门水质较差, 为α-中污或污染水体。  相似文献
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In the mud- and sandflat region of the outer Königshafen off List on Sylt, the effects of the outflow from a sewage treatment plant on the benthic diatom flora were investigated. The spectrum of shapes, biomass, and diversity was determined in relation to the concentrations of phosphate, silicate, and nitrogen compounds in the overlying and pore water. The biomass increased with the available quantities of nutrients, while the diversity reached a maximum at the intermediate concentrations. Every different set of nutrient concentrations is characterized by a different diatom community. Slight inputs of nutrients led to changes in the relative abundances of forms typical of the habitat. Moderate concentrations permitted the species that are normally present in winter to occur in summer as well. In the strongly eutrophic region, nutrient-loving species that are not locally present under normal conditions formed nearly monospecific populations. A relatively constant input of nutrients almost eliminated the seasonal variations. Navicula gregaria, Nitzschia sigma, and Nitzschia tryblionella proved to be tolerant of pollution, while the genera Achnanthes and Amphora were typical in the nutrient-poor regions. The nutrient budget, particularly that of the nitrogen compounds, was found to be predominant among the physical and chemical factors.  相似文献
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Artificial substrata have been used in diatom studies for almost 100 years. However, concern still exists over whether diatom communities developing on artificial substrata accurately represent communities developing on natural substrata. This study compares the diatom communities colonising glass slides and clay tiles in two coastal dune lakes, and compares these communities to the naturally occurring communities in the epipelon, epilithon, and epiphyton. Both glass microslides and clay tiles, incubated for three separate periods ranging from 29 to 68 days, resulted in replicate substratum samples supporting similar diatom community compositions at each site. The degree of variation between artificial substrata communities at different sites, and between the two artificial substrata types, was generally no more than the degree of variation between communities on different types of natural substrata. Additionally, the composition of the diatom communities on the artificial substrata was representative of the community composition on the natural substrata. The effects of incubation period and siting are discussed.  相似文献
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Despite the fact that biovolume calculation is a common procedure in most phytoplankton and periphyton studies, diatom community analyses are usually based on relative abundance data. In a biomonitoring context, a community metric that accounts for cell size could be of interest due to the potential differences that might exist in nutrient uptake between large and small-sized species. This paper addresses the question of whether diatom community analysis should be based on relative abundance, biovolume or cell surface. The results show that although community structure expressed as relative proportion of taxa varied according to the metric used, the ordinations conducted with each metric were similar. The explained percentage of species variance was slightly higher with the relative abundance metric compared to the metrics based on relative biovolume or cell surface area. Partial CCAs showed that each water chemistry variable generally explained a higher portion of species variance when the relative abundance was used. The analyses conducted with two size groups (small and large taxa) expressed as relative abundance and relative biovolume showed similar results. Moreover, our data showed that there is no significant relationship between diatom size and total phosphorus. According to these results, it seems that relative abundance would be the most appropriate metric to use for biomonitoring purposes. The biovolume and cell surface area calculations added substantially to the total analysis time due to the numerous measurements required, but did not improve the variance explained in community structure, and site ordinations were not significantly different. Electronic supplementary material Electronic supplementary material is available for this article at and accessible for authorised users.  相似文献
5.
The algal flora of the Truckee River below Reno, Washoe County, Nevada was examined during the summer and fall months of 1986. This reach of the lower Truckee River exhibited a substantial gradient in dissolved inorganic nitrogen associated with sources which included treated wastewater from the Reno metropolitan area. The algal communities were similar to those of other river systems of the Great Basin. Cyanophyta and Chlorophyta formed encrusting mats on the substrate, with the nitrogen fixer Calothrix atricha relatively abundant upstream from the nitrogen source. Diatoms were abundant within and upon this mat. A total of 139 diatom taxa and 11 taxa other than diatoms was identified from this flora. Several of the diatom taxa, including Achnanthes minutissima, Diatoma vulgare, Nitzschia dissipata, and Nitzschia palea, demonstrated distinct downriver patterns in relative abundance.  相似文献
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