稳定碳、氮同位素在生态系统研究中的应用

在简要介绍了稳定同位素测定方法之后 ,对稳定碳、氮同位素在生态系统领域中关于系统的碳源、能量流动、营养结构、污染物的生物放大作用及系统稳定性变化的应用研究作了较为系统的论述 ,并对稳定碳、氮同位素在赤潮研究、环境污染治理、生态动力学建模及有机分子化合物系列示踪技术等方面的应用提出展望     

Statistical evaluation of the performance of gridded monthly precipitation products from reanalysis data,satellite estimates,and merged analyses over China

Theoretical and Applied Climatology - In this study, we compared the following four different gridded monthly precipitation products: the National Centers for Environmental Prediction version 2...     

中国人才流动的地域模式及空间分布格局研究

依据教育部直属高校2015届本科毕业生生源与就业数据,采用指标评价与冷热点分析方法,分析升读大学与本科就业两个流动阶段的人才流动地域模式及省域空间分布格局。研究表明：① 人才流动具有明显的本地空间粘滞性特征,地域模式包括“本地-跃迁”型、“本地-半依附”型和“本地-依附”型。② 省际层面形成沿东南沿海与长江沿岸分布的“弓形”格局,显示了优势区域的整体粘滞性对人才高地形成的意义。研究指出,把握关键节点、依托城市群来发挥粘滞作用有助于城市推进引智工作。     

珠江三角洲震害预测数据库

叙述了珠江三角洲综合地震灾害数据库设计与实现的目的和任务，系统的设计思想及其主要功能和特点。     

下沟古火山机构的发现及其地质特征

下沟古火山机构位于走廊南山南坡中寒武统火山岩带的下沟地段。该火山岩带的扁麻沟——自柳沟地带爆发相火山岩广泛发育,火山岩与火山—沉积岩呈北西西向(与区域构造线一致)条带相间分布。我们的实地调查发现,这些爆发相火山岩条带是由一系列中心式火山机构组成的火山链(图1)。以前的研究者依据火山岩岩石化学特征,判定该火山岩带的火山岩属岛弧型火山岩。我们的研究成果使这一论断具体化。事实说明,扁麻沟——白柳沟     

加大开发力度,向现代化大矿业迈进

正确认识矿产资源省情,对确定青海省新的经济增长点至为重要。青海省是矿产资源大省,但市场需求旺盛的大宗主体矿产探明储量严重不足,居全国前5位的35种矿产几乎全部是低值的非金属矿产和伴生共生矿产,绝大多数为“呆”、“滞”储量,商品属性很低或目前尚不具备商品属性。因此,“矿产资源大省”只具口头上和纸面上的意义。 本文从建立现代化大矿业的角度对青海省矿产资源开发提出了一些新见解。如“开发资源,振兴青海”,不仅要开发资源,还要走深加工的道路;在适销高产值矿产资源(如金、银、宝玉石及有色金属矿产等)的勘查、开发上,可以以优惠政策吸引国内外资金投入于青海南部地区及青海北部有色金属、贵金属矿区的深部工作中。     

Contrasting changes in above- and below-ground biomass allocation across treeline ecotones in southeast Tibet

Under conditions of a warmer climate, the advance of the alpine treeline into alpine tundra has implications for carbon dynamics in mountain ecosystems. However, the above- and below-ground live biomass allocations among different vegetation types within the treeline ecotones are not well investigated. To determine the altitudinal patterns of above-/below-ground carbon allocation, we measured the root biomass and estimated the above-ground biomass (AGB) in a subalpine forest, treeline forest, alpine shrub, and alpine grassland along two elevational transects towards the alpine tundra in southeast Tibet. The AGB strongly declined with increasing elevation, which was associated with a decrease in the leaf area index and a consequent reduction in carbon gain. The fine root biomass (FRB) increased significantly more in the alpine shrub and grassland than in the treeline forest, whereas the coarse root biomass changed little with increasing altitudes, which led to a stable below-ground biomass (BGB) value across altitudes. Warm and infertile soil conditions might explain the large amount of FRB in alpine shrub and grassland. Consequently, the root to shoot biomass ratio increased sharply with altitude, which suggested a remarkable shift of biomass allocation to root systems near the alpine tundra. Our findings demonstrate contrasting changes in AGB and BGB allocations across treeline ecotones, which should be considered when estimating carbon dynamics with shifting treelines.     

Responses of soil inhabiting nitrogen-cycling microbial communities to wetland degradation on the Zoige Plateau,China

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.     

Immunogenicity and protective role of antigenic regions from five outer membrane proteins of <Emphasis Type="Italic">Flavobacterium columnare</Emphasis> in grass carp <Emphasis Type="Italic">Ctenopharyngodon idella</Emphasis>

Flavobacterium columnare causes columnaris disease in freshwater fish. In the present study, the antigenic regions of five outer membrane proteins (OMPs), including zinc metalloprotease, prolyl oligopeptidase, thermolysin, collagenase and chondroitin AC lyase, were bioinformatically analyzed, fused together, and then expressed as a recombinant fusion protein in Escherichia coli. The expressed protein of 95.6 kDa, as estimated by 10% sodium dodecyl sulfate-polyacrylamide gel electrophoresis, was consistent with the molecular weight deduced from the amino acid sequence. The purified recombinant protein was used to vaccinate the grass carp, Ctenopharyngodon idella. Following vaccination of the fish their IgM antibody levels were examined, as was the expression of IgM, IgD and IgZ immunoglobulin genes and other genes such as MHC Iα and MHC IIβ, which are also involved in adaptive immunity. Interleukin genes (IL), including IL-1β, IL-8 and IL-10, and type I and type II interferon (IFN) genes were also examined. At 3 and 4 weeks post-vaccination (wpv), significant increases in IgM antibody levels were observed in the fish vaccinated with the recombinant fusion protein, and an increase in the expression levels of IgM, IgD and IgZ genes was also detected following the vaccinations, thus indicating that an adaptive immune response was induced by the vaccinations. Early increases in the expression levels of IL and IFN genes were also observed in the vaccinated fish. At four wpv, the fish were challenged with F. columnare, and the vaccinated fish showed a good level of protection against this pathogen, with 39% relative percent survival (RPS) compared with the control group. It can be concluded, therefore, that the five OMPs, in the form of a recombinant fusion protein vaccine, induced an immune response in fish and protection against F. columnare.