大洋桥石藻Gephyrocapsa oceanica对海水酸化与营养盐胁迫的复合响应

本文选取了大洋桥石藻(Gephyrocapsa oceanica)作为实验对象,通过CO₂加富实验模拟海水酸化环境,分析了氮充足和氮相对不足条件下海洋颗石藻对海水酸化的生理响应。结果发现在两种营养盐状态下,CO₂加富均能一定程度促进大洋桥石藻种群增长与Chl a浓度的增加。对比两种营养盐状态,氮相对不足条件下的大洋桥石藻细胞密度和叶绿素含量均有最显著的提高,表明低营养盐浓度和低的氮磷比可能更有利于大洋桥石藻的生长繁殖。电镜观测结果显示酸化对大洋桥石藻的钙化作用具有显著的负影响,并且在氮相对不足条件下,大洋桥石藻的细胞个体变小及比表面积升高。研究结果表明在未来寡营养的大洋上层水体,大气CO₂浓度升高会对大洋桥石藻的生理功能产生负面影响,但可能刺激大洋桥石藻的生长。     

A method of batch-purifying microalgae with multiple antibiotics at extremely high concentrations

Axenic microalgal strains are highly valued in diverse microalgal studies and applications. Antibiotics, alone or in combination, are often used to avoid bacterial contamination during microalgal isolation and culture. In our preliminary trials, we found that many microalgae ceased growing in antibiotics at extremely high concentrations but could resume growth quickly when returned to an antibiotics-free liquid medium and formed colonies when spread on a solid medium. We developed a simple and highly efficient method of obtaining axenic microalgal cultures based on this observation. First, microalgal strains of different species or strains were treated with a mixture of ampicillin, gentamycin sulfate, kanamycin, neomycin and streptomycin (each at a concentration of 600 mg/L) for 3 days; they were then transferred to antibiotics-free medium for 5 days; and finally they were spread on solid f/2 media to allow algal colonies to form. With this method, five strains of Nannochloropsis sp. (Eustigmatophyceae), two strains of Cylindrotheca sp. (Bacillariophyceae), two strains of Tetraselmis sp. (Chlorodendrophyceae) and one strain of Amphikrikos sp. (Trebouxiophyceae) were purified successfully. The method shows promise for batch-purifying microalgal cultures.     

A Spatial Conditioned Latin Hypercube Sampling Method for Mapping Using Ancillary Data

For obtaining maps of good precision by the spatial inference method, the distribution of sampling sites in geographical and feature space is very important. For a regional variable with trends, the predicting error comes from trend estimation, variogram estimation and spatial interpolation. Based on the cLHS (conditioned Latin hypercube Sampling) method, a sampling method called scLHS (spatial cLHS) considering all these three aspects with the help of ancillary data is proposed in this article. Its advantage lies in simultaneously improving trend estimation, variogram estimation and spatial interpolation. MODIS data and simulated data were used as sampling fields to draw sample sets using scLHS, cLHS, cLHS with x and y coordinates as covariates, simple random and spatial even sampling methods, and the distribution and prediction errors of sample sets from different methods were evaluated. The results showed that scLHS performed well in balancing spreading in geographic and feature space, and can generate points pairs with small distances, and the sample sets drawn by scLHS produced smaller mapping error, especially when there were trends in the target variable.     

基于BP模型和Ward法的北京市平谷区乡村地域功能评价与分区

构建乡村地域功能评价指标体系,借助BP神经网络模型揭示平谷区“生产-生活-生态”功能分异特征;运用Ward法划分功能区,服务于平谷区乡村转型发展和功能区布局。结果表明：① 在多项功能综合作用下,平谷区基本形成了“平原地区生产功能较强、镇中心及周边村域生活功能明显、山地区以生态功能为主”的功能分布格局。② 基于评价结果和空间属性,平谷区划分为西部平原生产区、东部山地生态生产区、中部平原城市生活区、中部近郊平原生活区、东部丘陵生态生活区和北部山地生态区。其中,西部平原生产区、中部平原城市生活区、北部山地生态区是平谷三生空间功能发展的优势区域,分布相对集中。按照“强功能重优化、中等功能重提升、弱功能重改善”的原则提升乡村地域功能,促进地区均衡发展。     

Characteristics of mesoscale vortices over China in 2015

Mesoscale vortices, which appear at middle and lower levels of rainstorms, are cyclonic circulations with a size ranging from tens of kilometers to several hundred kilometers. Mesoscale vortices often have close relationships with convective activities. The ERA-Interim dataset and an automatic vortex-searching method were used to identify the mesoscale vortices occurring over China in 2015 and their basic characteristics were analyzed. The mesoscale vortices are divided into three categories: mesoscale convective vortices, mesoscale stratiform vortices, and mesoscale dry vortices. The mesoscale convective vortices have the largest intensity, size, and duration, whereas the mesoscale dry vortices have the smallest. Mesoscale convective vortices are able to form in any direction of the parent mesoscale convective system, although the secondary convection tends to appear to the southeast of the parent vortices. The mesoscale vortices tend to generate in the transition area between high and low altitudes. The leeward side of the Tibetan Plateau is the main source region of mesoscale vortices in China. Most of vortices are generated at midday and midnight. The activities of mesoscale convective vortices and mesoscale stratiform vortices peak in summer, whereas those of the mesoscale dry vortices peak in winter.     

冬季东亚主要行星尺度环流分量的时空特征及其相互行用

本文采用一种复经验正交函数分析方法和滤波技术,对1978—79年冬季全球冬季风实验资料系列FGGE-Ⅲb进行分析,尤其对东亚地区时间尺度10—20天的主要行星尺度环流分量进行分解,结果表明影响气压和厚度场的决定性因子是冷季风潮,受季风潮影响200百帕上无辐散风u_φ第一模态以1—2天滞后沿经向和纬向有类似于季风潮的传播;季风潮振动导致局地经向环流相应变化,以无旋风V_X第一模态表示的Hadley环流几乎无经向传播但有明显的纬向传播,并在传播过程中加强;热带对于副热带存在反馈并通过u_φ第二模态实现。在急流入口处u_X第二模态表示次级环流的存在,其水平尺度约20个纬距。     

Long-Term Joint Distribution of One-Tenth Large (or Significant) Wave Height with Average Period

- In this paper, by using the wave data from a few oceanographic observation stations in the coastal zone of the Yellow Sea, the East China Sea and the South China Sea, the long-term joint distribution of the one-tenth large (or significant) wave height with average period is studied. The statistical data demonstrate that the long- term distribution of the one- tenth wave height or average period fits the log-normal distribution, thus the joint distribution also fits the two-dimensional log-normal distribution. Then the conditional probability distribution of the average period is derived, and the range as well as the mode of the average wave period corresponding to a certain return period of wave height can be calculated easily.     

南海海盆的形成演化探讨

根据“陆缘扩张”理论,利用古地磁数据,结合地质、地球物理资料,对南海海盆的成因机制和演化过程进行探讨。结果得出:南海的多期多轴扩张及其形成演化,是在欧亚板块、太平洋板块和印度板块的联合作用下,中、新生代南海周缘的微板块和岛弧的相互运动以及南海海盆构造应力场不断变化的情况下逐渐完成的。     

The cause and mechanism of fluoride anomaly in krill

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