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本调查于2016年和2017年的5月、8月,对日照近岸海域浒苔暴发区进行了4个航次的浮游动物断面调查。4个航次中,2016年和2017年5月航次获得的种类数要明显低于同年8月航次,而平均丰度和湿重生物量均高于同年8月航次。造成这种情况的原因可能是调查海域8月浒苔暴发结束,浒苔的消亡过程会大量消耗营养盐,导致水体中营养盐含量下降,进而影响到其他浮游植物和浮游动物的生长。应用PRIMER软件中的单变量分析得到群落种数(S)、丰富度(d)、香农-威纳指数(Shannon-Weaner index)(H′)和均匀度(J),从多样性指数分析可以看出,5月航次的生物多样性均劣于同年8月航次。不同年度相同季节航次中出现的优势种极其相似,而不同季节航次出现的优势种则大不相同。 相似文献
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车载移动测量系统的测图精度受测量环境影响较大,而城市测量的环境一般较复杂,且环境对测量精度的影响程度并未明确,因此本文主要针对车辆在建筑物遮挡和拐弯两种情况下做了实验,同时对同一目标点的二维坐标和三维坐标进行了平面精度的对比,综合分析评价了Trimble MX7移动测量系统在实际应用中行驶轨迹精度和目标点位精度的变化情况。实验证明,轨迹拐弯处的点位精度比车辆直行时的点位精度差,但满足1∶1 000数字测图精度要求,在建筑遮挡最密集时点位精度最差但仍可应用于1∶1 000野外数字测图,直接对目标点的三维坐标进行提取的精度优于二维坐标提取方式,该测量系统可应用于1∶2 000野外数字测图的高程测量。 相似文献
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Microplankton communities of three coastal sites of Qingdao, Shandong Province, China were investigated using RAPD (random amplified polymorphic DNA) molecular markers and morphological observations. Eight RAPD-primers were selected to amplify the DNA polymorphy. The genetic distances inferred from the pairwise similari-ties were calculated for the phylogenetic tree construction. Meantime, the traditional microscopic determination, a way of visualizing the species composition, was performed to detect the major taxa of microplanktons from all samples. Results showed that: (1) the band sharing index values were in the range of 0. 504 2-0. 763 2 among samples from the same sampling site at different time scales, while 0.406 5-0.685 7 among the samples from different stations at the same time scales, indicating that spatial variations of microplankton communities were more pronounced than temporal ones; (2) samples from the same station basically clustered together, cor-responding to the geographic distribution of the sampling sites; (3) diversity derived from genetic and morpho-logical data did not correspond with each other well. 相似文献
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The feasibility of using fluorescence excitation-emission matrix (EEM) along with parallel factor analysis (PARAFAC) and nonnegative least squares (NNLS) method for the differentiation of phytoplankton taxonomic groups was investigated. Forty-one phytoplankton species belonging to 28 genera of five divisions were studied. First, the PARAFAC model was applied to EEMs, and 15 fluorescence components were generated. Second, 15 fluorescence components were found to have a strong discriminating capability based on Bayesian discriminant analysis (BDA). Third, all spectra of the fluorescence component compositions for the 41 phytoplankton species were spectrographically sorted into 61 reference spectra using hierarchical cluster analysis (HCA), and then, the reference spectra were used to establish a database. Finally, the phytoplankton taxonomic groups was differentiated by the reference spectra database using the NNLS method. The five phytoplankton groups were differentiated with the correct discrimination ratios (CDRs) of 100% for single-species samples at the division level. The CDRs for the mixtures were above 91% for the dominant phytoplankton species and above 73% for the subdominant phytoplankton species. Sixteen of the 85 field samples collected from the Changjiang River estuary were analyzed by both HPLC-CHEMTAX and the fluorometric technique developed. The results of both methods reveal that Bacillariophyta was the dominant algal group in these 16 samples and that the subdominant algal groups comprised Dinophyta, Chlorophyta and Cryptophyta. The differentiation results by the fluorometric technique were in good agreement with those from HPLC-CHEMTAX. The results indicate that the fluorometric technique could differentiate algal taxonomic groups accurately at the division level. 相似文献