2006年夏季珠江冲淡水驱动的上升流

根据珠江口及其附近海域2006年夏季（7-8月）航次水文调查资料,发现调查期间,除了西南季风驱动下的冲淡水东向扩散外,粤西珠江口外冲淡水主要呈西向扩散趋势,并且西向扩散的冲淡水下存在上升流。已有的模型研究中,西南季风下珠江口外没有出现上升流,说明西南季风不是珠江口外上升流产生的主导因素。观测的温盐分布、潜标流速时间序列与走航ADCP流态表明,上升流产生的原因是:（1）口门外冲淡水南向扩展驱动了垂向重力环流;（2）密度跃层以下东北向沿岸流的底边界层Ekman效应;（3）口门外冲淡水团之间的气旋型中尺度涡旋作用。     

Relationships of growth and mortality to enzymatic activity,and the relative mRNA expression of cultured scallops Patinopecten yessoensis in the Yellow Sea,China

The bottom aquaculture of yesso scallop (Patinopecten yessoensis) has developed rapidly in the north of Yellow Sea, China, but not without accompanying productivity problems. We, therefore, conducted field surveys to investigate factors related to growth and mortality rates of bottom-cultured scallops after release. Specifically, we focused on the effects of total antioxidant capacity (TAOC) and three key enzymes involved in antioxidant and metabolic function:glutamic pyruvic transaminase (GPT), lactic dehydrogenase (LDH), and superoxide dismutase (SOD). Across summer and winter, we also measured the relative mRNA expression of GPT and SOD to understand their seasonal variation in the scallops, along with how such variation correlated to growth and mortality. Results show that bottom cultured scallops experienced mass mortality during the first six months post-release. During winter (December), scallops grew more rapidly and suffered less mortality than in summer (August). The observed lower performance probably resulted from less advantageous environmental factors during the summer seasons, such as high temperature and low dissolved oxygen. These environmental stressors enhance protein consumption while decreasing energetic resources in scallops. Furthermore, scallops in summer exhibited high antioxidant levels that probably competed for energy with process integral to growth and survival. These negative factors combined to elevate mortality rates. In conclusion, we provided evidence suggesting correlations between metabolic/antioxidant activity and growth and mortality of bottom-cultured yesso scallops. These correlations implied us an accurate method to estimate the performance of bottom culture system. Suggestions about innovative aquaculture techniques were also discussed in the study. Our results might provide a possible guideline to the improvement of bottom culture techniques for this commercially valuable seafood species.     

湛江湾填海工程对水动力条件的影响预测

建立了湛江湾二维全流水动力学模型,模拟了湛江湾宝满码头填海工程前、后的水动力场。通过工程前后的流场比较,预测了围填工程对水动力场的影响,并优选了围填方案。     

梯级筑坝下小型山区河流水体碳氮磷的时空特征及富营养化风险

梯级筑坝对河流水环境演化的影响是国内外关注的热点.小型山区河流高密度梯级开发对水体生源要素的空间格局以及水环境演化的累积影响特征尚不清楚.以重庆市五布河为研究对象,对流域内8个“河流—水库—下泄水”交替系统中表层水体理化因子及碳(C)、氮(N)、磷(P)形态组成进行季节性监测,探讨了梯级筑坝对小型河流生源要素空间格局及水体富营养化风险影响的累积特征及驱动机制.结果表明：梯级水电开发对五布河流域水生生境和生源要素空间分配的影响具有潜在的累积效应,各库区水体碳氮磷浓度均呈逐级增加的空间规律;水库段的有机碳及不同形态的氮、磷浓度均高于入库河流,因此水体养分浓度呈现出河段尺度(即单个河流—水库—下泄水系统)和流域尺度(即上游至下游)耦合的空间变异模式.上游水库中溶解性氮、磷的再释放及下泄输移能够补给下游库区,加之下游水库泥沙对氮、磷的吸附—沉积作用的减弱,导致水体氮、磷总量及溶解性氮、磷的占比沿程增加,呈现梯级筑坝对水环境演化的累积影响.梯级筑坝影响下河流碳氮磷总量的相关性减弱,而溶解性养分间的相关性增强,形成了特殊的养分协同演化;水库群之间水力滞留时间的差异与水体碳氮磷浓度具有较好的线性关系...     

城市地下空间资源评价进展与展望

城市地下空间利用是拓展城市发展空间、优化城市空间布局、解决城市问题、提高城市治理能力及实现城市高质量发展的有效途径之一,对地下空间资源进行全面评价是保障地下空间安全利用的前提.文章系统分析了城市地下空间的资源属性及评价现状,梳理了目前主要的城市地下空间资源评价方法及其在不同城市的应用进展.当前,城市地下空间资源评价主要...     

贡嘎山东坡磨西河流域泥石流暴发的临界雨量值初探

在实地调查和前人研究的基础上,查明了贡嘎山东坡磨西河流域内泥石流沟的分布状况、暴发规律及危害特征等;并根据近20年来流域内发生的典型泥石流灾害,分析了泥石流发生前的降雨过程,发现磨西河流域内泥石流发生的当日雨量和前6 d有效雨量之间具有明显的幂函数关系,据此以泥石流发生的当日雨量和前6 d有效雨量为指标,初步探讨了磨西河流域内泥石流暴发的雨量值。     

青藏高原东南缘活动断裂地质灾害效应研究现状

青藏高原东南缘不同性质、不同类型、不同特点活动断裂发育且较为活跃,自2008年汶川地震发生以来,相继发生了玉树地震、庐山地震、鲁甸地震等。地震引发、触发、诱发产生了大量地质灾害,造成了惨重的生命财产损失。通过收集与分析相关资料,对青藏高原东南缘活动断裂地质灾害效应研究进展与取得成果进行了归纳总结,从活动断裂地质灾害主要控制因素,地质灾害发育特征、空间分布规律、演化模式、形成机制,不同性质断裂控制效应、断裂两盘差异效应、地震动参数效应、地形地貌效应等地质环境效应和地质灾害力学效应等方面进行了综述。在此基础上,对活动断裂地质灾害效应研究中存在的如不同类型活动断裂和不同震级地震与地震地质灾害相关性、以及地震地质灾害监测与风险评估等问题或重点研究方向进行了探讨,其研究结果为地震地质灾害致灾机理、风险评估、防灾减灾等研究提供参考。      

东准噶尔北缘早石炭世构造体制转变:来自碱性花岗岩年代学和地球化学制约

新疆东准噶尔北缘位于西伯利亚板块和哈萨克斯坦-准噶尔板块的结合部位,是中亚造山带的重要组成部分,也是新疆北部最重要的成矿带之一。老山口碱性花岗岩和乔夏哈拉碱性花岗岩即位于该区域,LA-ICP-MS锆石U-Pb年龄显示其结晶年龄分别为330.5±3.5 Ma和331.1±3.1 Ma。结合区域内存在的多处近同时期的碱性花岗岩(布尔根碱性花岗岩、哈腊苏碱性花岗斑岩、乌图布拉克碱性花岗岩),指示东准噶尔北缘存在一期重要的早石炭世碱性花岗岩岩浆活动,并大致可分为东、中、西三段。这些早石炭世碱性花岗岩具有高硅(SiO_2=67.14%~83.02%)、富碱(Na_2O+K_2O=5.37%~10.73%)、低钛(TiO_2=0.04%~0.23%)、贫钙(CaO=0.04%~1.19%)的特征,与典型A型花岗岩特征相类似,成因类型上属A1型花岗岩,个别具有A2-A1型花岗岩过渡性质。微量元素组成具有富集大离子亲石元素K、Rb及高场强元素Nb、Zr、Hf、Th,亏损Ba、Sr、P、Eu、Ti的特征。轻稀土元素明显富集(LREE/HREE=3.42~8.11),具强烈的负Eu异常(δEu=0.03~0.74),稀土元素配分模式呈右倾海鸥型。岩石具有较高的ε_(Hf)(t)(7.6~12.4)和ε_(Nd)(t)值(5.4~6.9)。上述特征表明,这些碱性岩的母岩浆具有复杂的成因,推测为幔源岩浆底侵到下地壳,促使下地壳先存的富Nb玄武岩部分熔融,并发生岩浆混合,经过一定程度的分离结晶形成。综合本文数据及地质事实,我们认为东准噶尔北缘在358 Ma部分地区开始进入板内后造山伸展环境,即板内早期环境,但早石炭世(360~327 Ma)整体处于由后碰撞向板内后造山环境转化的过渡阶段。东准噶尔北缘东、中、西段进入板内环境的时间不尽相同,可能与其多俯冲岛弧系统拼贴增生时代的不均一性有关。     

Distribution of eruptive volcanic basalt in the South China Sea and adjacent areas by interpreting gravity,magnetic and seismic data

Volcanic basalt eruption activity in the South China Sea and adjacent areas occurred strongly in Cenozoic E ra. However, it is difficult to define their ranges and spatial locations.This paper presents the methods of reduction to the magnetic equator in low latitudes to bring out a better correlation between magnetic anomalies and their causing-sources; high-frequency filtering is to separate gravity and magnetic anomalies as well as information about the volcanic basalts in the upper part of the Earth’s crust; 3D total gradient is to define the spatial location of high density and magnetic bodies. The distribution of eruptive volcanic basalt is determined by multi-dimensional correlation analysis between high frequency gravity and magnetic anomalies with weighted total gradient 3D.The results from the above-mentioned methods have shown that the distribution of the eruptive volcanic basalt is mainly concentrated along the South China Sea’s sea floor-spreading axis, transitional crust, Manila trench and some large faults zone. These results are improved by existing boreholes and seismic data in the study area.     

金属矿床勘查与开发定量生态评估体系初探:以福建罗卜岭斑岩型铜钼矿为例

定量评估矿床的经济价值与未来勘查开发对生态环境产生的影响,可以缓解矿产资源开发与生态文明建设之间的矛盾.基于多元数据,构建了以驱动力-压力-状态-影响-响应(Driving-Pressure-State-Impact-Response,DPSIR)模型为理论框架的综合评价指标体系,包含6个一级指标和23个二级指标.根据评价等级表,利用多层次模糊综合评价法进行指标权重计算以及综合均值分析,建立了一个完整的评估体系.该体系在福建罗卜岭斑岩型矿床开发设计中的应用表明,福建罗卜岭矿区开发适宜度评价为Ⅱ级,即对当地的经济发展起到明显的推动作用,但对生态环境会产生轻微干扰.该方法能较好地反映金属矿床勘查与开发对生态的综合影响,可操作较强,可为国土资源、环境保护以及矿山企业等部门进行矿产资源的开发评估提供参考.