Preliminary study on assessment of nutrient transport in the Taihu Basin based on SWAT modeling

With the Taihu Basin as a study area, using the spatially distributed and mechanism-based SWAT model, preliminary simulations of nutrient transport in the Taihu Basin during the period of 1995:_2002 has been carried out. The topography, soil, meteorology and land use with industrial point pollution discharge, the loss of agricultural fertilizers, urban sewerage, and livestock drainages were all considered in the boundary conditions of the simulations. The model was calibrated and validated against water quality monitoring data from 2001 to 2002. The results show that the annual total productions of nitrogen (TN) and phosphorus (TP) into Lake Taihu are 40000t and 2000t respectively. Nutrient from the Huxi Region is a major resource for Lake Taihu. The non-point source (surface source) pollution is the main form of catchment sources of nutrients into Lake Taihu, occupied TN 53% and TP 56% respectively. TN and TP nutrients from industrial point pollution discharge are 30% and 16%, and sewerage in both forms of point source and non-point source are TN 31% and TP 47%. Both the loss of agricultural fertilizers and livestock drainages from the catchment should be paid more attention as an important nutrient source. The results also show that SWAT is an effective model for the simulation of temporally and spatially nutrient changes and for the assessment of the trends in a catchment scale.     

秦岭和华北地区地壳低速层的成因探讨──岩石高温高压波速实验证据

对秦岭和华北地区地壳主要岩类１３８个样品进行高温高压实验,测量其纵波速度的结果表明,其中５４个样品出现了纵波低速现象．对出现该现象的样品的实验产物所做的肉眼和镜下观察、电子探针分析以及综合对比显示,微裂隙不是产生低速现象的决定因素,而主要是含水矿物（角闪石、黑云母等）的脱水相交和由之引发的岩石部分熔融导致岩石出现纵波低速现象．通过实验条件与中、下地壳的温度和压力等条件的类比揭示,秦岭和华北地区中、下地壳存在的低速（高导）层也可能是由含水矿物的脱水相变或岩石部分熔融引起的．     

远区重力数据对扰动位径向二阶梯度的影响

提出了利用地面重力异常数据计算地面扰动位径向二阶梯度时，远距离带区影响的误差公式，结果以级数形式给出，以其数学模型为基础，利用全球重力位模型GPM98，计算确定了不同平均异常网格大小情况下截断半径取一系列值时的远区影响，在将卫星重力梯度和航空重力梯度观测数据与地面重力数据进行联合处理时，文中提出了远区影响的数量关系，对于确定合理的截断半径大小具有一定的参考价值。     

西藏鄂雅错盐湖砷和汞的分布特征研究

本研究对西藏鄂雅错盐湖和主要支流中不同形态的砷(亚砷酸盐As(Ⅲ)、砷酸盐As(Ⅴ)、一甲基砷酸MMA、二甲基砷酸DMA)和总汞(THg)含量进行了测定,并与主要水质参数进行相关性分析研究,结果表明鄂雅错盐湖As主要以As(Ⅴ)形态存在,其次分别为As(Ⅲ)、DMA和MMA,其中无机砷的含量明显大于有机砷。相比较其他砷的形态,盐湖中As(Ⅲ)与主要水质参数的相关性显著,与总溶解性固体(TDS)、总溶解态氮(DTN)呈显著的强正相关性,与水温、溶解氧 (DO)、氧化还原电位(Eh)、pH呈显著负相关性。总汞浓度较低,且与主要水质参数相关性不显著。通过风险评价发现鄂雅错湖水中砷存在一定的致癌健康风险,汞不存在风险。本研究丰富了西藏盐湖和支流水体中砷、汞分布特征及其环境影响因素的认识,对于环境保护具有一定的意义。     

Relationships between Genetic Diversity of Vascular Plant Species and Climate Factors

Genetic diversity is crucial for plants to respond to global climate change, and exploring relationships between genetic diversity and climatic factors may help predict how global climate change will shape the genetic diversity of plants in the future. So far, however, the extent and magnitude of the impact of climatic factors on the genetic diversity of plants has not been clarified. We collected data from 68 published papers on two widely used measures of genetic diversity of populations (average expected heterozygosity (He) and average observed heterozygosity (Ho)) and on localities of populations of 79 vascular plants, and extracted data on 19 climatic factors from WorldClim. We then explored the relationships between measures of genetic diversity and climatic factors using linear regressions. He of plant populations was significantly correlated with climatic factors in 58.7% (44) of the 75 species that used He as a measure of genetic diversity, and Ho was correlated with climatic factors in 65.1% (41) of the 63 species that used this genetic diversity measure. In general, Mean Temperature of Wettest Quarter, Precipitation Seasonality, Precipitation of Driest Quarter and Temperature Seasonality played a vital role in shaping He, and Ho was mostly correlated with Precipitation of Warmest Quarter, Mean Temperature of Wettest Quarter, Precipitation of Driest Quarter and Precipitation of Driest Month. Also, the proportion of the significant correlations between genetic diversity of populations and climatic factors was higher for woody than for herbaceous species, and different climatic factors played different roles in shaping genetic diversity of these two growth forms. Our results suggest that climate may play an important role in shaping genetic diversity of plant populations, that climatic change in the future may alter genetic diversity of plants, and that genetic diversity of different plant forms may respond to climatic change differently.     

广西隆林卡林型金矿地质特征及成因探讨

广西隆林卡林型金矿主要产于上二叠统合山组泥质条带状灰岩及砂质白云岩中,受背斜或穹窿构造核部的高角度正断层控制明显,矿体呈脉状或似层状,矿石类型包括块状、条带状、碎粒状等。根据金矿产状和下伏碳酸盐岩地层具有较高的金丰度,推测该地区金矿成因与热液流体活动密切相关;最后还对研究区找矿标志和找矿潜力进行了探讨。这项研究为我国西南碳酸盐岩地区寻找金矿提供了新的思路。     

四川地区短时强降水事件时空演变特征研究

利用四川地区自动气象站逐小时降水观测资料,分析了2010~2019年5~9月短时强降水事件24h累计降水量、频次和强度的时空分布特征,探讨了短时强降水事件发生的频次、极值分布及其与地形、海拔高度等的关系。结果表明：四川地区平均24h累计降雨量基本在50mm以上,盆地东北部、西南部、南部及阿坝州东部甚至超过100mm,最大值出现在广安,达175mm。四川地区短时强降水事件开始时间的日变化特征表现为“V”型结构的夜间峰值位相,事件持续时段多为傍晚至凌晨,时长可达10h以上,最长甚至可持续22h。在强降水事件极值的日变化上,极大值频次和降水量呈单峰结构,在03时达到最大,其后逐渐减小至15时达到谷值,而后再次增大;降水强度呈弱双峰结构,分别在04时和16时达到谷值,13时和18时达到峰值,其日变化呈“增-减-增-减”的特征。四川短时强降水事件与复杂地形有密切的关系,5~6月事件活跃区在四川盆地中部,7月在盆地西部的龙门山脉一带,8月在雅安、乐山附近,9月在盆地北部且频次明显减少;短时强降水事件的最大小时雨强可达80mm以上,出现在7~8月的盆地西部龙门山一带和南部地区。短时强降水事件随着海拔高度的增加,发生频次和日数逐渐减少,海拔2000m以上地区基本无强降水发生日出现( 峨眉山气象站例外)。     

四川盆地江油厚坝油砂有机地球化学特征与成因研究

四川江油厚坝油砂产出于侏罗系沙溪庙组下段,含油砂层沿北东方向延伸约25 km.露头和岩芯油砂样抽提得到氯仿沥青“A”含量为0.4％～33％.抽提物饱和烃GC-MS分析得到的分子有机地球化学特征表明,油砂油遭受严重生物降解,饱和烃分布呈现双大鼓包,正构烷烃和异构烷烃基木被降解;三环萜烷含量丰富,孕甾烷和升孕甾烷含最也较高...     

Effect of diet on the development,survival, and reproduction of the calanoid copepod Pseudodiaptomus dubia

Pseudodiapto,mus dubia is a calanoid copepod abundant in the mariculture ponds of southern China.However,our understanding of the population dynamics of P.dubia in aquaculture ponds is limited.In this study,groups of larval P.dubia were each fed a different microalgal species,and the effects of these different diets on development,survival,and reproduction were assessed.The five microalgae used were species common in aquaculture farms in China,and included two chlorophytes(Chlorella saccharophila and Platymonas subcordiformis),one golden microalga(Isochrysis zhan.jiangensis),and two diatoms(Chaetoceros muelleri and Cyclotella meneghinia,na).Our results indicated that C.saccharophila was not a suitable food for larval P.dubia,as all larvae fed this microalga died at stage Ⅲ(as copepodites).The survival rates of P.dubia larvae fed C.muelleri,Ⅰ. zhanjiangensis,and P.subcordiformis were significantly higher than that of larvae fed C.meneghiniana.In the adult stage,copepods fed C.muelleri,I. zhanjiangensis,and C.meneghiniana produced more nauplii(430-566 nauplii/female),had higher intrinsic growth rates(0.2-0.253/d),and better longevity(59-60 days)than those fed P.subcordiformis.Our results therefore suggest that P.dubia has different nutritional needs and food preferences at different life stages.For example,P.subcordifonnis was suitable for developing larvae but not for breeding adults,while C.meneghiniana was suitable for breeding adults but not for developing larvae.Both C.muelleri and I.zhanjiangensis were excellent foods for P.dubia throughout the entire life cycle.     

2017-08-09新疆精河Ms6.6地震附近区域相对应变的变化分析

2017年精河M_S6.6地震震前,尼勒克、巴伦台和小泉沟台钻孔应变仪记录到显著的应变变化,经现场落实确认,异常是可靠的。根据这3个台的记录资料计算相对应变的变化,结果表明,地震前最大（小）主应变大小和方向分别出现明显加速和急剧偏转变化。此外还发现,相对应变场异常期间主方向与震源机制解P轴方位较为一致。