Impacts of climate change on net primary productivity in arid and semiarid regions of China

In recent years, with the constant change in the global climate, the effect of climate factors on net primary productivity(NPP) has become a hot research topic. However, two opposing views have been presented in this research area: global NPP increases with global warming, and global NPP decreases with global warming. The main reasons for these two opposite results are the tremendous differences among seasonal and annual climate variables, and the growth of plants in accordance with these climate variables. Therefore, it will fail to fully clarify the relation between vegetation growth and climate changes by research that relies solely on annual data. With seasonal climate variables, we may clarify the relation between vegetation growth and climate changes more accurately. Our research examined the arid and semiarid areas in China(ASAC), which account for one quarter of the total area of China. The ecological environment of these areas is fragile and easily affected by human activities. We analyzed the influence of climate changes, especially the changes in seasonal climate variables, on NPP, with Climatic Research Unit(CRU) climatic data and Moderate Resolution Imaging Spectroradiometer(MODIS) satellite remote data, for the years 2000–2010. The results indicate that: for annual climatic data, the percentage of the ASAC in which NPP is positively correlated with temperature is 66.11%, and 91.47% of the ASAC demonstrates a positive correlation between NPP and precipitation. Precipitation is more positively correlated with NPP than temperature in the ASAC. For seasonal climatic data, the correlation between NPP and spring temperature shows significant regional differences. Positive correlation areas are concentrated in the eastern portion of the ASAC, while the western section of the ASAC generally shows a negative correlation. However, in summer, most areas in the ASAC show a negative correlation between NPP and temperature. In autumn, precipitation is less important in the west, as opposed to the east, in which it is critically important. Temperatures in winter are a limiting factor for NPP throughout the region. The findings of this research not only underline the importance of seasonal climate variables for vegetation growth, but also suggest that the effects of seasonal climate variables on NPP should be explored further in related research in the future.     

华北1999—2009年水平形变应变场特征

根据华北地区GPS观测数据计算了华北活动块体的运动速度和应变率,以及块体边界带的活动速率和应变率,研究了华北块体的运动和应变率特征,以及边界断裂带的应力作用特征。形变揭示出华北亚板块从西向东运动方向由东向偏转为南东向,NE NNE向断裂带呈现右旋,NWW EW向断裂带呈现左旋。各个次级块体的主压应变应力轴方向存在一定的差异。边界断裂带现今应变应力状态页不相同,郯庐断裂带北段和山西断陷带以压性为主,具有应变能积累显示,但是应变率相对较小,应变能积累缓慢。     

The ultrastructure of the spermatozoon of Octopus ocellatus Gray, 1849 (Cephalopoda: Octopoda)

Morphology of the spermatozoon of Octopus ocellatus was studied by light, scanning electron, and transmission electron microscopes. Sperm are 600–700 μm long, with a large number of granules in diameter about 130 nm. Each spermatozoon is composed of a head, neck, and tail. The head is made up of an acrosomal complex anterior to the nucleus. The spiral acrosomal complex consists of an electron-lucent vesicle, lacuna, and an electron-dense acrosomal vesicle. Additionally, the spiral acrosomal vesicle has numerous equidistant striations, and is surrounded by many small granules (20 nm diameter). A long straight nucleus, which is electron-densed, has a deep posterior concavity, the nuclear vacuole. At the terminal end of the nucleus is a sleeve-like structure with a concave posterior nuclear fossa (PNF). The neck is short connecting the PNF. The basal body is located in the PNF and gives rise to the axoneme. This structure connects the head, neck, and tail. The tail is divided into a middle piece and a principal piece. The middle piece, having a 9+9+2 arrangement, is surrounded by a mitochondrial sheath and terminates by an electron-dense fibrous sheath. The principal piece is the longest part of the sperm with coarse fibers tapering posteriorly. The results of this study shall provide some useful information for artificial breeding of this species.     

Construction of a metagenomic DNA library of sponge symbionts and screening of antibacterial metabolites

To study the bioactive metabolites produced by sponge-derived uncultured symbionts, a metagenomic DNA library of the symbionts of sponge Gelliodes gracilis was constructed. The average size of DNA inserts in the library was 20 kb. This library was screened for antibiotic activity using paper disc assaying. Two clones displayed the antibacterial activity against Micrococcus tetragenus. The metabolites of these two clones were analyzed through HPLC. The result showed that their metabolites were quite different from those of the host E. coli DH5α and the host containing vector pHZ132. This study may present a new approach to exploring bioactive metabolites of sponge symbionts.     

Variations of snow temperature and their influence on snow cover physical parameters in the Western Tianshan Mountains, China

This article discussed about snow temperature variations and their impact on snow cover parameters. Automatic temperature recorders were used to sample at 10-minute intervals at the Tianshan Station for Snow-cover and Avalanche Research, Chinese Academy of Sciences. 10-layer snow temperature and the snow cover parameters were measured by the snow property analyzer (Snow Fork) in its Stable period, Interim period and Snow melting period. Results indicate that the amplitude of the diurnal fluctuation in the temperature during Snow melting period is 1.62 times greater than that during Stable period. Time up to the peak temperature at the snow surface lags behind the peak solar radiation by more than 2.5 hours, and lags behind the peak atmospheric temperature by more than 0.2 hours during all three periods. The optimal fitted function of snow temperature profile becomes more complicated from Stable period to Snow melting period. 22 h temperature profiles in Stable period are the optimal fitted by cubic polynomial equation. In Interim period and Snow melting period, temperature profiles are optimal fitted by exponential equation between sunset and sunrise, and by Fourier function when solar radiation is strong. The vertical gradient in the snow temperature reaches its maximum value at the snow surface for three periods. The peak of this maximum value occurs during Stable period, and is 4.46 times greater than during Interim period. The absolute value of temperature gradient is lower than 0.1°C cm⁻¹ for 30 cm beneath snow surface. Snow temperature and temperature gradient in Stable period∼Interim period indirectly cause increase (decrease) of snow density mainly by increasing (decreasing) permittivity. While it dramatically increases its water content to change its permittivity and snow density in Snow melting period.     

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A quantitative analysis of the surge of March 19, 1989

A large surge event appearing in AR 5395 was observed at the Yunnan Observatory on March 19, 1989. H spectral profiles of the event are interpreted by using a two-cloud model and the contours of three parameters: excitation temperature, T _exc, microturbulent velocity, V _t ,and column density of hydrogen atoms at the second level, N _0,2, are obtained, respectively. The question about the unique feature of the solution obtained by the fitting method is also discussed. The results show that the surge is composed of some conglomerated materials with higher temperature and density; the mass ejection is probably intermittent. Neither T _exc nor N _0,2 vary with the height over the solar limb but decrease from the center to the periphery of the surge. V _t varies from 10 to 30 km s^-1 and decreases with height. Some other important parameters, such as electron density, n _e ,and electron pressure, P _e ,etc., have also been estimated. In the surge, with N _0,2 about 2.0 × 10¹² cm^-2 and T _exc about 8500 K on average, we obtained n _e = 1.80 × 10¹⁰ cm^-3 and P _e = 0.023 dyn cm^-2. The energy variations of the surge during the ascending phase are estimated.     

不同养殖类型池塘浮游生物群落结构的初步分析

1988年在山东省禹城县渍涝洼地中选择四口鱼塘以不同放养类型进行试验,4—10月测定其浮游生物数量、生物量的变化。根据浮游生物各主要大类(如原生动物、轮虫以及蓝藻、绿藻、硅藻、隐藻和裸藻等)的变化,分析不同养殖类型池塘浮游生物群落结构变化的稳定性和同步性,同时分析了环境因子特别是生物营养物质的变化对浮游生物的影响。结果指出,肥水性鱼类在养殖池塘中因搭配比例的差异而导致池塘中浮游生物变化。     

A study on stability of physically coated mercury film electrode

In this paper, a new method of maintaining the high sensitivity and stability of a physically coated mercury film electrode is proposed, and its mechanism is explained. The polarographic analysis procedure in this method can be simplified, the analysis precision can be raised, and the life of the electrode can be prolonged. The method is practical. Contribution No. 1338 from Inst. of Ocean., Academia Sinica.     

通量均衡意义下中国大陆现今地壳垂直运动及梯度分布与构造活动的关系

本文在应绍奋等研究成果的基础上,利用作者所提出的方法重新处理了覆盖中国大陆(不包括海南省、台湾省等岛屿)900余万平方公里的垂直形变资料,给出了在通量均衡基准下中国大陆现今地壳垂直运动及其梯度的空间分布以及几大地块的平均速率和通量。由此得出以下认识:(1)现今地壳垂直运动与大陆所处的力场有较好的对应性。(2)现今地壳垂直运动具有明显的南升北降大趋势;以西部最为典型和强烈。(3)现今地壳垂直运动高梯度值带与地震带的分布有较好的吻合性。(4)现今地壳垂直运动的分群性与大陆各大地块的划分有较好的匹配性。