共查询到20条相似文献，搜索用时 783 毫秒
1.
Shanshan Zhang Rongguo Su Yali Duan Cui Zhang Zhijie Song Xiulin Wang 《中国海洋大学学报(英文版)》2012,11(3):339-346
The discrete excitation-emission-matrix fluorescence spectra (EEMS) at 12 excitation wavelengths (400, 430, 450, 460, 470, 490, 500, 510, 525, 550, 570, and 590 nm) and emission wavelengths ranging from 600-750 nm were determined for 43 phytoplankton species. A two-rank fluorescence spectra database was established by wavelet analysis and a fluorometric discrimination technique for determining phytoplankton population was developed. For laboratory simulatively mixed samples, the samples mixed from 43 algal species (the algae of one division accounted for 25%, 50%, 75%, 85%, and 100% of the gross biomass, respectively), the average discrimination rates at the level of division were 65.0%, 87.5%, 98.6%, 99.0%, and 99.1%, with average relative contents of 18.9%, 44.5%, 68.9%, 73.4%, and 82.9%, respectively; the samples mixed from 32 red tide algal species (the dominant species accounted for 60%, 70%, 80%, 90%, and 100% of the gross biomass, respectively), the average correct discrimination rates of the dominant species at the level of genus were 63.3%, 74.2%, 78.8%, 83.4%, and 79.4%, respectively. For the 81 laboratory mixed samples with the dominant species accounting for 75% of the gross biomass (chlorophyll), the discrimination rates of the dominant species were 95.1% and 72.8% at the level of division and genus, respectively. For the 12 samples collected from the mesocosm experiment in Maidao Bay of Qingdao in August 2007, the dominant species of the 11 samples were recognized at the division level and the dominant species of four of the five samples in which the dominant species accounted for more than 80% of the gross biomass were discriminated at the genus level; for the 12 samples obtained from Jiaozhou Bay in August 2007, the dominant species of all the 12 samples were recognized at the division level. The technique can be directly applied to fluorescence spectrophotometers and to the developing of an in situ algae fluorescence auto-analyzer for phytoplankton population. 相似文献
2.
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
3.
In vivo fluorescence methods are efficient tools for studying the distribution of phytoplankton in nature.Different algae species usually have different pigments with different ratios,which results in different fluorescence emission spectra.Based on multiple excitation wavelength fluorescence emission spectra,a discrimination technique is established in this study.The discrimination method,established by multivariate linear regression and weighted least-squares,was used to differentiate the samples cultured in the laboratory and collected from Jiaozhou Bay near Qingdao at the division level.The correctly discriminated samples were ≥ 86% for single algae samples,≥ 88% for simulatively mixed ones,≥ 91% for physically mixed ones and 100% for samples collected from Jiaozhou Bay.The result in this research is more definite for the physically mixed samples in the laboratory.The method described here can be employed to monitor the phytoplankton population in the marine environment. 相似文献
4.
5.
手机通话位置数据已经成为全球范围内广泛使用的人类活动研究数据,其为高时空分辨率的人口分布估计提供了一种新的途径。然而,手机通话位置数据具有不规则稀疏采样的特点,其反映出的人口分布可能具有一定误差。本研究以深圳市为例,首次结合24 h连续定位的手机信令数据,分别从时间和地理维度量化分析了使用手机通话位置数据估计24 h人口分布的偏差,同时探讨了剔除低频用户对上述偏差的影响。本研究揭示,在居民活跃时间段,使用通话用户的分布估计人口分布时,相对误差的中位数在25%~30%之间;城市内部的土地利用类型与通话用户人口估计偏差具有显著的关联;剔除低频用户会略微减小土地利用对人口分布偏差的影响。本研究成果可帮助理解手机通话位置数据在估计高时空分辨率人口分布上的局限性和适用性,为合理使用手机通话位置数据进行相关研究和应用提供科学依据。 相似文献
6.
基于底栖动物完整性指数的南广河河流健康评价 总被引：1，自引：0，他引：1
根据2012 年南广河（四川境内段）17 个采样断面（3 个参照点,14 个受损点）6 次底栖动物采样数据,对18 个生物参数进行分布范围、判别能力和Pearson 相关性分析,最终确定南广河流域生物完整性指数（B-IBI）由EPT 分类单元数、甲壳动物和软体动物分类单元数、甲壳动物和软体动物的个体相对丰度、敏感类群分类单元数、耐污类群的个体相对丰度、捕食者个体相对丰度和襀翅目个体相对丰度等7 个指数组成.采用比值法统-各入选生物参数量纲,计算其IBI 指数值和B-IBI 指标赋分（BIBr）值.结果表明,在17 个采样断面中,BIBr 分值在90 分以上的有6 个,80～90 分之间的有3 个,70～80 分之间的有2 个,60～70 分之间的有4 个,60 分以下的有2 个.从分布趋势看,BIBr 分值较高的点（80 分以上）主要分布在支流（如塘坝乡、马家岩）和干流上游少数几个点（如石碑乡、沐滩村和凉水井）,而下游特别是接近河口部分的几个采样断面均较低,大窝镇和南广镇两个断面的分值更在60 分以下. 相似文献
7.
Sargassum muticum is one of the most abundant and conspicuous native macroalgae species on the northern coasts of China. It often forms large-scale seaweed beds in subtidal zones. This investigation was designed to understand the intraspecific genetic relationships of this alga based on samples collected from four northern coastal sites of China, and to evaluate gamete release and growth capacity in laboratory conditions. The nuclear internal transcribed spacer 2 （ITS2） sequences of 16 samples from four locations were identical. Based on cox3 gene and partial rbcLS operon sequences, intraspecific genetic variability was detected with three and two ribotypes, respectively. Temperature, not irradiance, was shown to significantly affect gamete release and fertilization. Elevated temperature and irradiance enhanced the growth of germlings and vegetative branchlets. Maximum growth rate of germlings was detected at 18-24℃and an irradiance of 60-100 μmol photons/（m^2.s）. Under ambient conditions （12-25℃ and 60-125 gmol photons/ （m2.s））, relative growth rate of young branchlets could reach 7.5%/d. 相似文献
8.
Cottonseed meal (CM) was used at up to 36.95% content in the diet (replacing 60% of dietary fish meal protein) without any negative eff ects on growth performance of pre-adult grass carp (initial body weight, 761 g) under outdoor conditions. A culture trial was conducted in net cages installed in a large concrete pond. Seven isonitrogenous and isoenergetic diets containing a gradient of CM concentrations (0, 12.2%, 24.4%, 36.6%, 48.8%, 54.8%, and 61.0%) as replacement for dietary fish meal protein (0, 20%, 40%, 60%, 80%, 90%, and 100%) were formulated. Dietary non-resistant starch (from maize) was inverse to dietary CM. Growth performance and feed utilization of fish fed the diets containing CM replacing 0–40% fishmeal protein were not aff ected after the 6-week feeding trial. Accumulation of hepatopancreatic total gossypol in the hepatopancreas was significantly correlated with free gossypol content in the diets (HTG=88.6+1.5×DFG, R 2=0.89, P<0.05). Intestinal α-amylase and γ-glutamyl transpeptidase activities rose along with increasing dietary CM level. The structure of the mid-intestinal tissues and the ultrastructure of the enterocyte microvilli were normal when dietary CM was <36.6% (60% protein replacement). Increasing dietary CM content increased serum alanine aminotransferase levels but decreased serum alkaline phosphatase, cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, triglycerides, and albumin (P<0.05). 相似文献
9.
The wetlands on the Zoige Plateau have experienced serious degradation, with most of the original marsh being converted to marsh meadow or meadow. Based on the 3 wetland degradation stages, we determined the effects of wetland degradation on the structure and relative abundance of nitrogen-cycling (nitrogen-fixing, ammonia-oxidizing, and denitrifying) microbial communities in 3 soil types (intact wetland: marsh soil; early degrading wetland: marsh meadow soil; and degraded wetland: meadow soil) using 454-pyrosequencing. The structure and relative abundance of nitrogen-cycling microbial communities differed in the 3 soil types. Proteobacteria was the predominant phylum in most soil samples but the most abundant soil nitrogen-fixing and denitrifying microbial bacteria differed at the class, order, family, and genus levels among the 3 soil types. At the genus level, the majority of nitrogen-fixing bacterium sequences related to Bradyrhizobium were from marsh and marsh meadow soils; whereas those related to Geobacter originated from meadow soil. The majority of ammonia-oxidizing bacterium sequences related to Nitrosospira were from marsh (except for the 40-60 cm layer), marsh meadow and meadow soils; whereas those related to Candidatus Solibacter originated from 40-60 cm layer of marsh soil. The majority of denitrifying bacterium sequences related to Candidatus Solibacter and Anaeromyxobacter were from marsh and meadow soils; whereas those related to Herbaspirillum originated from meadow soil. The distribution of operational taxonomic units (OTUs) and species were correlated with soil type based upon Venn and Principal Coordinates Analysis (PCoA). Changes in soil type, caused by different water regimes were the most important factors influencing compositional changes in the nitrogen-fixing, ammonia-oxidizing, and denitrifying microbial communities. 相似文献
10.
The effects of various salinity fluctuation amplitudes (2, 4, 6 and 8) on the growth, osmolarity, Na+-K+-ATPase activity and Hsp70 of juvenile Fenneropenaeus chinensis cultured in seawater with a salinity of 20 were studied. The results show that weight gain in the salinity fluctuation treatments was better than that in control; in particular, the weight gain of treatments S4 and S0, at 231.8% and 196.3%, respectively, was significantly different (P<0.05). The hemolymph osmolarity of treatments S0, S2, S4, S6 and S8 was 635.4, 630.8, 623.6, 614.4 and 600.3 mOsm/kg, respectively, and decreased with increasing salinity fluctuation amplitude. The level of Na+-K+-ATPase activity in gills of F. chinensis was higher than that in hepatopancreas, but there were no significant differences among all treatments, either in gills or hepatopancreas (P>0.05). The relative level of Hsp70 in treatment S4 was 48.4% and 40.4% higher than control in muscle and eyestalks, respectively, with the highest values being recorded under a salinity fluctuation amplitude of 4. 相似文献
11.
【目的】了解马氏珠母贝(Pinctada fucata martensii)肠道及其养殖水体可培养细菌的群落组成。【方法】采用2216E平板涂布法研究海区养殖马氏珠母贝肠道与养殖水体的可培养菌群种类及丰度。【结果与结论】马氏珠母贝肠道及其养殖水体的可培养细菌归属于2门(变形菌门和厚壁菌门)3纲7目10科23属56种。属水平上,肠道中以弧菌属(74.7%)和假交替单胞菌属(18.7%)为主;养殖水体中α-变形菌纲的FJ943236_g属(40.7%)丰度最大,弧菌属(16.7%)相对肠道丰度较低。样品共有菌属为弧菌属、假交替单胞菌属、发光杆菌属和芽孢杆菌属;肠道特有菌属为希瓦氏菌属和盐单胞菌属;养殖水体特有菌属主要为FJ943236_g、鲁杰氏菌属和Nautella。在种水平上,7个种为二者共有;马氏珠母贝肠道和养殖水体特异性菌种分别为18个和31个。虽然门水平上马氏珠母贝肠道中可培养细菌群落与其养殖水体中的细菌群落大致相似,但在属、种水平上二者差异明显。 相似文献
12.
13.
DNA barcoding provides accurate identification of zooplankton species through all life stages. Single-gene-targeted metagenomic analysis based on DNA barcode databases can facilitate longterm monitoring of zooplankton communities. With the help of the available zooplankton databases, the zooplankton community of the Changjiang (Yangtze) River estuary was studied using a single-gene-targeted metagenomic method to estimate the species richness of this community. A total of 856 mitochondrial cytochrome oxidase subunit 1 (cox1) gene sequences were determined. The environmental barcodes were clustered into 70 molecular operational taxonomic units (MOTUs). Forty-two MOTUs matched barcoded marine organisms with more than 90% similarity and were assigned to either the species (similarity>96%) or genus level (similarity<96%). Sibling species could also be distinguished. Many species that were overlooked by morphological methods were identified by molecular methods, especially gelatinous zooplankton and merozooplankton that were likely sampled at different life history phases. Zooplankton community structures differed significantly among all of the samples. The MOTU spatial distributions were influenced by the ecological habits of the corresponding species. In conclusion, single-gene-targeted metagenomic analysis is a useful tool for zooplankton studies, with which specimens from all life history stages can be identified quickly and effectively with a comprehensive database. 相似文献
14.
Flow cytometric determinations of the abundance distribution and community structure of picophytoplankton (i.e., Prochlorococcus spp., orange fluorescence Synechococcus spp. and picoeukaryotes) were used for samples taken from the Philippine Sea in the western tropical Pacific Ocean from September to October of 2004. A fluorescence probe was employed to detect Chlorophyll a (Chl a). Abundances of Prochlorococcus spp., orange fluorescence Synechococcus spp. and picoeukaryotes ranged from 0.1 to 58×103 cells ml?1, 0.38 to 17×102 cells ml?1 and 0.42 to 26×102 cells ml?1, respectively. Synechococcus spp. and picoeukaryotes co-occurred in relatively shallow water with the maximum abundance observed at 50 to 70 m depth, while Prochlorococcus spp. only occurred in the 70 to 200 m layer. Prochlorococcus spp. was the dominant picophytoplankton population in terms of abundance and biomass. The cell size and carbon biomass content were estimated for the three picophytoplankton groups. In addition, among the three groups of picophytoplankton, the relative contribution of red fluorescence to the total red fluorescence varied with depth. The fluorescence and light scatter properties of individual cells indicated that in the upper 100 m layer, picoeukaryotes were a major contributor to total red fluorescence, while at the depth below 100 m, Prochlorococcus spp. and Synechococcus spp. made an important contribution to the total red fluorescence. 相似文献
15.
We tested the use of otolith shape analysis to discriminate between species and stocks of five goby species( Ctenotrypauchen chinensis, Odontamblyopus lacepedii, Amblychaeturichthys hexanema, Chaeturichthys stigmatias, and Acanthogobius hasta) found in northern Chinese coastal waters. The five species were well differentiated with high overall classification success using shape indices(83.7%), elliptic Fourier coefficients(98.6%), or the combination of both methods(94.9%). However, shape analysis alone was only moderately successful at discriminating among the four stocks(Liaodong Bay, LD; Bohai Bay, BH; Huanghe(Yellow) River estuary HRE, and Jiaozhou Bay, JZ stocks) of A. hasta(50%–54%) and C. stigmatias(65.7%–75.8%). For these two species, shape analysis was moderately successful at discriminating the HRE or JZ stocks from other stocks, but failed to effectively identify the LD and BH stocks. A large number of otoliths were misclassified between the HRE and JZ stocks, which are geographically well separated. The classification success for stock discrimination was higher using elliptic Fourier coefficients alone(70.2%) or in combination with shape indices(75.8%) than using only shape indices(65.7%) in C. stigmatias whereas there was little difference among the three methods for A. hasta. Our results supported the common belief that otolith shape analysis is generally more effective for interspecific identification than intraspecific discrimination. Moreover, compared with shape indices analysis, Fourier analysis improves classification success during inter- and intra-species discrimination by otolith shape analysis, although this did not necessarily always occur in all fish species. 相似文献
16.
Gut microorganisms play an important role in the digestion of their host animals. The purpose of this research was to isolate and assess the enzyme-producing microbes from the Apostichopus japonicus gut. Thirty-nine strains that can produce at least one of the three digestive enzymes (protease, amylase, and cellulase) were qualitatively screened based on their extracellular enzyme-producing abilities. The enzyme-producing strains clustered into eight groups at the genetic similarity level of 100% by analyzing the restriction patterns of 16S rDNA amplified with Mbo I. Phylogenetic analysis revealed that 37 strains belonged to the genus Bacillus and two were members of the genus Virgibacillus. Enzyme-producing capability results indicate that the main enzyme-producing microflora in the A. japonicus gut was Bacillus, which can produce protease, amylase, and cellulase. Virgibacillus, however, can only produce protease. The high enzyme-producing capability of the isolates suggests that the gut microbiota play an important role in the sea cucumber digestive process. 相似文献
17.
Dewi Seswita Zilda 《中国海洋大学学报(英文版)》2012,11(2):213-218
A total of 69 strains of thermophilic bacteria were isolated from water, soil and sediment samples from three Indonesia’s hot spring areas (Pantai cermin, Kalianda and Banyu wedang) by using Minimal Synthetic Medium (MSM). The extreme thermophile Brevibacillus sp. PLI-1 was found to produce extracellular thermophilic alkaline protease with optimal activity at 70℃ and pH 8.0-9.0. The molecular weight of the protease was estimated to be around 56 kD by SDS-PAGE. The maximum activity of the protease was 26.54 U mL-1. The protease activity did not decrease after 30 min and still retained more than 70% of relative activity after 60 min at 70℃ and pH 8.0. The ion Mg2+ was found to promote protease activity at both low and high concentrations, whereas Cu2+ and Zn2+ could almost completely inhibit the activity. Divalent cation chelator EDTA inhibited the enzyme activity by 55.06% ± 0.27%, while the inhibition caused by PMSF, Leupeptin, Pepstain A and Benzamidine were 66.78% ± 3.25%, 52.37% ± 0.25%, 62.47% ± 2.96% and 50.99% ± 0.24%, respectively. Based on these observations, the enzyme activity was conspicuously sensitive to the serine and cysteine protease inhibitors. All these results indicated that the protease isolated from the strain PLI-1 was a thermophilic protease and had a high-temperature stability and a pH stability. 相似文献
18.
高分辨率遥感对地观测为我们从空间与时间2个维度客观反演地表格局—过程提供了有效的技术支撑。本文遵循时空协同的研究思路,基于高分辨率遥感影像,开展了农业遥感领域2个典型的问题研究：① 提出了一种基于影像视觉特征的耕地分区分层提取方法,该方法在利用DEM数据进行分区的基础上,根据不同区域内耕地所呈现的几何特征和纹理特征差异,分别设计了不同的耕地提取模型;② 构建了一种地块尺度的作物生长参数反演方法,方法以地块为基本单元,在空间、时间及属性组合约束下进行作物理化参数反演。本研究以贵州省安顺市西秀区和广西扶绥县耕地提取进行了耕地地块提取示范,以扶绥县进行了基于耕地地块和中空间分辨率时间序列遥感数据的甘蔗叶面积指数反演。其中,对于安顺市西秀区的耕地地块提取结果而言,形态精度（IoU）大于0.7的地块超过60%,规则耕地、梯田以及林草地等的类型精度均超过了80%;对于扶绥县甘蔗叶面积指数反演的结果而言,其结果可以较为精确地反映出基地甘蔗与非基地甘蔗的差异,基地甘蔗在品质上要优于非基地甘蔗。西南山地区的耕地形态提取/类型判别和地块甘蔗叶面积指数应用验证均证明了方法的可行性。结果表明,协同使用多源高分辨率数据是实现精准农业遥感研究的有效途径。 相似文献
19.
Accurate quantification of astaxanthin from Haematococcus crude extract spectrophotometrically 总被引：2，自引：1，他引：1
The influence of alkali on astaxanthin and the optimal working wave length for measurement of astaxanthin from Haematococcus crude extract were investigated, and a spectrophotometric method for precise quantification of the astaxanthin based on the method of Boussiba et al. was established. According to Boussiba's method, alkali treatment destroys chlorophyll. However, we found that: 1) carotenoid content declined for about 25% in Haematococcus fresh cysts and up to 30% in dry powder of Haematococcus broken cysts after alkali treatment; and 2) dimethyl sulfoxide (DMSO)-extracted chlorophyll of green Haematococcus bares little absorption at 520-550 nm. Interestingly, a good linear relationship existed between absorbance at 530 nm and astaxanthin content, while an unknown interference at 540-550 nm was detected in our study. Therefore, with 530 nm as working wavelength, the alkali treatment to destroy chlorophyll was not necessary and the influence of chlorophyll, other carotenoids, and the unknown interference could be avoided. The astaxanthin contents of two samples were measured at 492 nm and 530 nm; the measured values at 530 nm were 2.617 g/100 g and 1.811 g/100 g. When compared with the measured values at 492 nm, the measured values at 530 nm decreased by 6.93% and 11.96%, respectively. The measured values at 530 nm are closer to the true astaxanthin contents in the samples. The data show that 530 nm is the most suitable wave length for spectrophotometric determination to the astaxanthin in Haematococcus crude extract. 相似文献
20.
The evolutionary relationships and taxonomic position of two marine planktonic bacterial strains BSw20211 and BSw10014, isolated from the Canada Basin and from the Southern Ocean, respectively, were determined using a polyphasic taxonomic approach. There was a close phylogenetic relationship between the two strains and most phenotypic properties were shared. Nonetheless, they were found to belong to different species of the genus Pseudoalteromonas on the basis of genotypic analyses. Findings were consistent with the suggestion that gyrB gene sequence comparison and DNA-DNA relatedness might better define phylogenetic relationships of bacteria at the species level. However, a cut-off value of 90% gyrB gene sequence similarity was not reliable for the differentiation of species within the genus Pseudoalteromonas. 相似文献