长江中下游典型浅水湖泊沉积物水界面磷与铁的耦合关系

目前普遍认为磷铁耦合关系是P迁移的主要机制,但大部分研究结果并未提供直接的原位证据.为了探索沉积物剖面磷(P)与铁(Fe)的耦合关系,利用Zr O-Chelex薄膜扩散梯度技术(ZrO-Chelex DGT),分别对太湖、巢湖、鄱阳湖和洞庭湖4个浅水湖泊沉积物有效态Fe和P进行高分辨采样和分析.结果表明,不同湖区有效态Fe和P浓度在沉积物-水界面处开始增加,之后波动变化,垂向异质性较强,但两者浓度变化同步.有效态P和Fe浓度的相关分析结果证明两者浓度具有显著的线性相关.室内厌氧培养实验进一步表明,Fe~(3+)的还原性促使Fe~(2+)与铁结合态磷的释放,促使DGT有效态P与Fe同步变化.该结果表明沉积物P的二次迁移和释放受Fe氧化还原过程的控制,为铁磷耦合关系提供了直接证据.     

牙鲆与夏鲆杂交及回交子代胚胎发育及早期生长比较

通过人工授精技术对牙鲆(Paralichthys olivaceus )和夏鲆( Paralichthys dentatus )进行了正反交及回交实验,并比较了正反交、回交子代的胚胎发育时序和仔稚幼鱼的生长.结果表明:孵化水温18.0±0.5℃下,初孵仔鱼破膜用时为:牙鲆41 h,正交鲆47 h,回交牙鲆42 h30 min,回交夏鲆44 h;16.5±0.5℃下,夏鲆61 h 40 min,反交鲆66 h.正交及两组回交子代在胚胎期均可正常发育.反交子代卵裂期出现异常,仅少数胚胎可以孵化.胚胎孵化后,在1~64日的培养过程中,反交鲆于3~4 d 内全部死亡,回交牙鲆发育至18日龄时全部死亡.正交鲆和回交夏鲆可正常发育,与牙鲆没有明显差别     

矿山废石淋溶对水环境的影响

为了研究废石堆砌对水环境的影响,通过对废石做淋溶实验,分析了出入水的水质变化规律,对废石衍生环境效应的过程、机制、影响因素方面进行讨论,揭示了人们容易忽视的酸性水中硫酸根、总硬度、微量金属离子的动力学变化机理,指出矿山废石对水环境的污染不至限于使水质酸化,硫酸根、总硬度也会大幅度提高,废石堆放应充分考虑当地的地理气候及水文条件,合理堆放,减少污染。     

Development,urban planning and political decisions. A triad that built territories at risk

Natural Hazards - Chilean geography exposes the country to high-level risks such as earthquakes and tsunamis. The disasters of 1930, 1960, 2010, and 2014 testify to the continuous link between...     

Transcriptional response of Microcystis aeruginosa to the recruitment promoting-benthic bacteria

Blooms of Microcystis aeruginosa occur frequently in many freshwater ecosystems around the world, but the mechanism of recovery has not been fully understood. I...     

3D alluvial aquifer reconstruction in polluted areas by means of GPR (Sabiñánigo,N Spain)

Assumptions of simple geometries for alluvial deposits (related to main rivers) can preclude determination of complexities that are revealed as fundamental controls in underground flow. Although subhorizontal contacts between alluvial and substratum materials are expected, previous sedimentary or erosional processes can result in irregular geometries, only accessible through detailed analysis. The studied case presents the 3D reconstruction of a Quaternary terrace in the proximities of Sabiñánigo (Southern Pyrenees, Northeastern Spain), lying on homogeneous Eocene marls. The studied area is located in an industrialized area supporting strongly pollutant chemical industry (chlorinated pesticides) for the past 50 years. The objective of the study was to constrain the groundwater pathway along the area to subsequently analyze leakage of chemicals to the water table. In order to reveal preferred flow paths, a detailed characterization of the internal structure of the alluvial deposits (0.5–13 m thick) and their relations with the Tertiary substratum was carried out by means of ground penetrating radar (GPR, 50 and 100 MHz antennas). The obtained models permit identifying several topographic highs in the alluvial/substratum contact, determining preferred pathways in water flow, favoring particular conditions associated with low levels of the water table. The presented results support the interest of application of GPR surveys in order to characterize the groundwater pathways in expected homogeneous areas and their importance in order to establish the contaminant surveillance network.     

Accurate analytical nutation series

In this letter we present the first accurate analytical nutation series, deduced from the Hamiltonian theory by the authors. They provide the highest accuracy ever obtained by any analytical nutation series, since the deviation in CEP (celestial ephemeris pole) offsets with respect to that of the IERS Conventions 1996 is kept below 1 mas in the time domain, in spite of still lacking ocanic corrections.     

我国九大气候区降水特性及其物理成因的研究Ⅱ——我国各区降水与环流因子的关系

利用ECMWF的格点风和位势高度场资料，对1998年夏季热带内外地区大气低频振荡特征进行了分析研究。结果表明，亚洲季风区的季节内振荡非常显著。850hPa季节内振荡纬向风的经向传播揭示出南海地区的西风振荡受南北两支西风的共同影响。与长江流域特大洪涝密切相关的大气环流系统(乌拉尔阻高和西太平洋副高)对季节内振荡有较强的响应。在欧亚范围，持续性异常环流十分活跃，大气低频波的活动与环流持续异常的形成有密切的联系，季节内振荡是高低纬环流持续异常同时发生的纽带。其低频(30—60d)遥相关型的分布同江淮洪涝年的波列结构相类似。     

高性能计算系统性能评测方法及其应用

为满足国家级气象数值模式业务系统对高性能计算资源不断增长的需求,提供规模更大、性能更优的高性能计算支撑平台,在高性能计算系统引进工作中开展了基于气象数值模式应用的高性能计算系统性能评测技术研究。该文将行业标准与实际业务应用相结合,设计了高性能计算系统性能评测方案,建立了中国气象局气象行业高性能计算系统性能评测模型。共选取10个测试程序,分别对单节点性能、网络性能和加速比等8个指标进行了测试和量化评分,并对主要测试结果中具有代表性的气象要素场进行了物理意义合理性检查。评测结果表明:评测方案设计合理,评测模型研究取得较好效果,保障了高性能计算系统引进工作顺利完成。