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排序方式: 共有321条查询结果,搜索用时 15 毫秒
1.
淮河干流及主要支流夏季浮游植物群落生物多样性评价 总被引:6,自引:0,他引:6
浮游植物是水生态系统的重要组成部分,其群落变化与水体环境条件密切相关,是反映河流健康的主要生物指标.为揭示淮河流域浮游植物群落特征及其与水质的相互关系,于2015年夏季对淮河流域典型水体—淮河干流、沙颍河、涡河和淠河进行系统的水质及浮游植物调查,探明浮游植物群落及其空间分布特征,并结合水体理化指标和生物指数进行水质评价.结果表明,淮河干流及主要支流27个点位中共获得浮游植物8门71属153种,主要隶属于绿藻门(Chlorophyta)、硅藻门(Bacillariophyta)、蓝藻门(Cyanophyta).浮游植物密度为0.019×10~5~131.824×10~5ind·L~(-1),不同河段浮游植物分布表现出较为显著的空间差异性,平均密度大小呈现沙颖河淮河干流涡河淠河的特点.非参数多维尺度分析(Non-metric Multidimensional Scaling,NMDS)表明,淮河干流、淠河和涡河的浮游植物群落组成和结构的相似性较高,而与沙颍河的浮游植物群落存在一定的差异.Shannon多样性指数H'介于0.78~3.21之间,Margalef丰富度指数D介于1.03~4.79之间,Pielou均匀度指数J介于0.12~0.73之间.水质生物评价结果显示,淮河流域大部分水体处于中等污染状况,部分点位处于重污染状况,其结果与水质综合污染指数评价结果具有较好的一致性.研究结果可为淮河水污染防治和水生态修复提供基础依据. 相似文献
2.
3.
霍邱群含铁建造(BIF)在成因上与国内外许多前寒武纪的BIF有明显的差别。通过岩石学、岩石化学、地球化学、人工重砂等研究,系统地恢复了它的原岩。成因争论较大的斜长角闪岩类的REE模式及ΣREE,表现出太古代沉积起源的特点。因此,它应是一套陆缘坳陷带内的沉积建造。矿层主要赋存在各旋回的中上部,与泥质岩、碳酸盐沉积物伴生,类似苏必利尔型。通过矽线石、兰晶石、榴石等七种矿物共生组合的热力学计算,其变质条件是P≈6±0.5Kb;T≈650-750℃。 相似文献
4.
锅炉烟气脱硫技术发展综述 总被引:4,自引:0,他引:4
在调查研究的基础上,论述国内外烟道气脱硫技术的发展与前景,提出开发生产适合我国国情的烟气脱硫技术势在必行。还简要介绍了最为普遍的石灰/石灰石法脱硫基本原理。 相似文献
5.
7.
关于既有民用建筑定期安全检测与维修问题的探讨 总被引:2,自引:0,他引:2
分析了既有民用建筑的现状,论述了既有民用建筑进行定期安全检测与维修的重要性,建议国家应制定既有民用建筑定期安全检测与维修的相关法规,并加强管理,保证实现工程的设计使用年限及延长建筑物的使用寿命,最大程度地发挥投资效益。 相似文献
8.
在国民经济中占有主导地位的油气企业同时也是造成环境污染的主体之一。因此,建立油气企业环境会计制度有极其重要的现实意义。文章针对我国油气企业环境会计制度应用现状,运用环境会计基本理论,对企业环境会计核算方法及信息传播模式进行了探讨,以期为油气企业环境会计制度的实施提供一些理论依据和具体方法,推动油气企业环境会计制度的发展。 相似文献
9.
T. R. Pope 《Behavioral ecology and sociobiology》2000,48(4):253-267
Evaluation of evolutionary mechanisms proposed to promote cooperative behavior depends on the relative influence of the behavior
on the reproductive success of individuals, the reproductive success of the group in which they interact behaviorally, and
the degree of gene correlation among cooperators. The genetic relationship within cooperative coalitions of female red howler
monkeys was examined for three populations with different densities and growth rates. Patterns of gene correlation change
within coalitions is documented using data from the mitochondrial and nuclear genomes, and long-term census monitoring. Differences
in fecundity and infant survivorship within and between groups of unrelated (rˉ=0) and related (rˉ≥ 0.25) females are compared. Females that emigrate from their natal groups form coalitions with other migrant females. These
coalitions attempt to establish a territory and, once successful in producing offspring, exclude other females from feeding
resources. Females in these coalitions had different mtDNA haplotypes and a genetically estimated mean r of 0, supporting demographic data on emigration patterns indicating that these females rarely have the opportunity to form
coalitions with kin. Patterns of recruitment and rate of matriline development within social groups supported behavioral data
indicating that females actively attempt to promote their own matriline as breeders over that of other females, and that some
matrilines are more successful at this than others. Mean r among females was significantly higher in coalitions established as social groups for several generations (rˉ=0.44). In these groups, females all shared the same mtDNA haplotype, and mtDNA haplotype divergence was significantly higher
between than within groups. Females in coalitions with kin had significantly higher reproductive success than females in unrelated
coalitions in all populations. This difference was not a function of coalition size, number of males, socionomic sex ratio,
or primiparity, although anecdotal evidence suggests that allomothering may compensate for inept new mothers in related coalitions
more often than in unrelated ones. Differences in territory quality could not be ruled out as a potential causal factor in
the saturated populations, but were unlikely in the low-density, growing population. There were substantial differences among
long-established coalitions in overall reproductive output in all three populations, and this was significantly correlated
with the number of breeding females. Increase in coalition size was a function of both group age and the behavioral tolerance
among females. Regardless of the underlying reasons for the patterns observed, reproductive success clearly increases with
degree of gene correlation among females within cooperative coalitions, and coalitions that recruit more daughters produce
more offspring. The nature of the cooperative relationship among group females directly influences both of these outcomes.
This is associated with substantial genetic differentiation among social groups within populations, creating conditions in
which genetic tendencies towards cooperative behavior can become tightly associated with group reproductive success.
Received: 15 September 1999 / Revised: 27 April 2000 / Accepted: 27 May 2000 相似文献
10.