珠江口海域春季富营养化现状与影响分析   总被引：1，自引：0，他引：1       下载免费PDF全文

谢群  施玉珍  张际标  陈春亮  孙省利 《应用海洋学学报》2017,36(3):356-364

随着珠江三角洲经济圈的迅速发展,珠江口海域环境污染日趋严重,于2014年春季对珠江口邻近海域进行环境现状调查,并通过因子分析法和聚类分析法就珠江口调查海域管辖城市和邻近区域的环境现状对珠江口海域环境污染的贡献率进行排序和分类.结果表明:珠江口调查海域营养盐污染较为严重,无机氮含量范围为0.213~1.963 mg/dm~3,平均值为0.888 mg/dm~3;活性磷酸盐含量范围为0.009~0.063 mg/dm~3,平均值为0.033 mg/dm~3.无机氮和活性磷酸盐在珠江口上游和中游均超过海水水质第四类标准,珠江口下游无机氮含量符合海水水质第四类标准,活性磷酸盐含量符合海水水质第二类标准.无机氮以硝氮为主,氨氮次之,亚硝氮含量最低.珠江口调查海域DIN/P变化范围为8.5~168.0,平均值为31.8;富营养化指数E变化范围为0.3~45.1,平均值为8.2,富营养化较为严重.来自广州、东莞、佛山、中山的四大口门排入的污染物对珠江口海域环境影响最大,其次是深圳西部海域沿岸和前海湾、深圳湾排入的污染物,最后是珠海、澳门和香港带入的污染物.从珠江口邻近海域环境现状对珠江口海域环境影响进行较为深入地分析和探讨,为珠江口海域环境的治理和修复提供一些意见和建议.  相似文献   

Effects of varying densities on serum reproductive parameters in pen-reared juvenile female rainbow trout <Emphasis Type="Italic">Oncorhynchus mykiss</Emphasis> farms     

侯志帅  温海深  李吉方  何峰  刘群  王金环  管标  王庆龙 《中国海洋湖沼学报》2017,35(1):98-108

The primary goal of this study was to assess the effect of varying densities on serum reproductive parameters of immature rainbow trout Oncorhynchus mykiss. Experimental trout were maintained in intensive, pen-reared farms for 300 days in fresh water reservoirs. Initial densities were 4.6, 6.6, and 8.6 kg/m³ (40, 60, 80 ind./m³), indicated as SD1, SD2, SD3, and final densities were 31.1, 40.6, 49.3 kg/m³, respectively. A summary of the ovarian stages were observed by histological examination. Serum E₂ (estradiol), T (testosterone) were evaluated by radioimmunoassay and FSH (follicle-stimulating-hormone), LH (luteinizing-hormone), vitellogenin, 17α,20β-P (17α,20βdihydroxy4-pregnen-3-one) were measured by enzyme-linked immunosorbent assay. Our findings demonstrated that ovarian development were retarded (from stage III to stage IV) at highest rearing density (SD3) after 180 days of intensive culture (over 40.6 kg/m³). In addition, we observed an inverse relationship between serum reproductive parameters and rearing density. Furthermore, compared to serum reproductive parameters of SD1, E₂, T, FSH, vitellogenin, 17α,20β-P, GSI and LH of two higher density groups decreased firstly and significantly at 60 (over 15.9 kg/m 3 ), 180 (over 31.7 kg/m 3 ), 180 (over 40.6 kg/m³), 240 (over 36 kg/m³), 240 (over 36 kg/m³), 240 (over 45 kg/m³) and 300 (over 49.3 kg/m³) days, respectively. Comparing serum reproductive parameters within the same ovarian development stage of rainbow trout from varying densities revealed that higher population density also led to significantly lower overall serum reproductive parameters. Overall, this study presents the reproductive, endocrinological parameters of juvenile female rainbow trout at high rearing densities and indicates the need for rainbow trout (114.44±5.21 g, 19.69±0.31 cm) that are initially stocked at 6.6 or 8.6 kg/m³ should be classified and subdivided into lower density after 180 days of farming (not over 31.7 kg/m³).  相似文献   

Effects of different gap filling methods and land surface energy balance closure on annual net ecosystem exchange in a semiarid area of China     

DU Qun  LIU HuiZhi  FENG JianWu  WANG Lei 《中国科学:地球科学(英文版)》2014,57(6):1340-1351

Based on eddy covariance measurements over two kinds of land surfaces(a degraded grassland and a maize cropland)in a semiarid area of China in 2005 and 2008,the effects of different gap filling methods,energy balance closure and friction velocity threshold(u*)on annual net ecosystem exchange(NEE)were analyzed.Six gap filling methods,including mean diurnal variation(MDV),marginal distribution sampling(MDS),and nonlinear regressions method,were investigated by generating secondary datasets with four different artificial gap lengths(ranging in length from single half-hours to 12 consecutive days).The MDS generally showed a good overall performance especially for long gaps,with an annual sum bias error less than 5 g C m-2 yr-1.There was a large positive annual sum bias error for nonlinear regressions,indicating an overestimate on net ecosystem respiration.The offset in the annual sum NEE for four nonlinear regressions was from 8.0 to 30.8 g C m-2 yr-1.As soil water content was a limiting factor in the semiarid area,the nonlinear regressions considering both soil temperature and soil water content as controlling variables had a better performance than others.The performance of MDV was better in daytime than in nighttime,with an annual sum bias error falling between-2.6 and-13.4 g C m-2 yr-1.Overall,the accuracy of the gap filling method was dependent on the type of the land surface,gap length,and the time of day when the data gap occurred.The energy balance ratio for the two ecosystems was nearly 80%.Turbulent intensity had a large impact on energy balance ratio.Low energy balance ratio was observed under low friction velocity during the night.When there was a large fetch distance in a wind direction,a low energy balance ratio was caused by mismatch of the footprints between the available energy and turbulent fluxes.The effect of energy balance correction on CO2 flux was evaluated by assuming the imbalance caused by the underestimation of sensible heat flux and latent heat flux.The results showed an average increase of 10 g C m-2 yr-1 for annual NEE in both ecosystems with an energy balance correction.On the other hand,the u*threshold also have a large impact on annual sum NEE.Net carbon emission increased 37.5 g C m-2 yr-1 as u*threshold increased from 0.1 to 0.2 m s-1,indicating a large impact of imposing u*threshold on net ecosystem carbon exchange.  相似文献   

一种有效追踪油气运移轨迹的新方法--断面优势运移通道的提出及其应用   总被引：16，自引：3，他引：13  

罗群庞雄奇  姜振学 《地质论评》2005,51(2):156-162

作为油气运移的重要通道,断裂的不同部位对油气的输导能力具有很强的不均一性,从而造成沿油源断裂分布的油气圈闭具有明显的油气差异聚集结果。断而优势运移通道的提出改变了以往人们认为开启的断裂都是油气运移通道的错误观念,强调只有沿着断面优势运移通道寻找勘探目标,才可能发现油气藏。本文通过分析断裂带输导能力的不均一性,提出断而优势运移通道概念及其油气汇聚运移原理,断面优势运移通道分析步骤和方法,并以柴达木盆地北缘儿条主要的控油气断裂为例,分析了不同部他油气运移的优势运移通道并对其附近的油气圈闭含油气性进行了评价,结果与勘探成果相符。  相似文献   

华池油田华152区低渗透砂岩储层敏感性及其形成机理   总被引：1，自引：0，他引：1  

李群  郭建华  郭原草  苏调红 《矿物岩石》2009,29(2)

华池油田华152区长3油层组储层为曲流河三角洲粉-细粒长石砂岩、岩屑长石砂岩,矿物成分成熟度低,结构成熟度中等,填隙物含量较高,孔隙结构以中孔细喉型为主,物性较差,属低渗透储层。主要成岩矿物（伊利石、绿泥石、伊／蒙混层、高岭石、方解石、白云石等）使储层对外来流体有不同程度的敏感性反应。“五敏”实验结果表明,储层速敏和碱敏均为弱-中等偏弱,部分伊/蒙混层、绿泥石、碳酸盐矿物含量高的样品表现出强水敏、强酸敏、强盐敏的特征;油田水结垢实验表明,注入水与地层水、储层岩石不配伍产生盐垢CaCO3,CaSO4,实验为开采过程中回注地层水和注气开采等工艺提供油层保护的理论依据。  相似文献   

The physical structures of snow and sea ice in the Arctic section of 150°-180°W during the summer of 2010     

HUANG Wenfeng  LEI Ruibo  ILKKA Matero  LI Qun  WANG Yongxue  LI Zhijun 《海洋学报(英文版)》2013,32(5):57-67

The physical structures of snow and sea ice in the Arctic section of 150°-180°W were observed on the basis of snow-pit, ice-core, and drill-hole measurements from late July to late August 2010. Almost all the investigated floes were first-year ice, except for one located north of Alaska, which was probably multi-year ice transported from north of the Canadian Arctic Archipelago during early summer. The snow covers over all the investigated floes were in the melting phase, with temperatures approaching 0℃ and densities of 295-398 kg/m3 . The snow covers can be divided into two to five layers of different textures, with most cases having a top layer of fresh snow, a round-grain layer in the middle, and slush and/or thin icing layers at the bottom. The first-year sea ice contained about 7%-17% granular ice at the top. There was no granular ice in the lower layers. The interior melting and desalination of sea ice introduced strong stratifications of temperature, salinity, density, and gas and brine volume fractions. The sea ice temperature exhibited linear cooling with depth, while the salinity and the density increased linearly with normalized depth from 0.2 to 0.9 and from 0 to 0.65, respectively. The top layer, especially the freeboard layer, had the lowest salinity and density, and consequently the largest gas content and the smallest brine content. Both the salinity and density in the ice basal layer were highly scattered due to large differences in ice porosity among the samples. The bulk average sea ice temperature, salinity, density, and gas and brine volume fractions were-0.8℃, 1.8, 837 kg/m3 , 9.3% and 10.4%, respectively. The snow cover, sea ice bottom, and sea ice interior show evidences of melting during mid-August in the investigated floe located at about 87°N, 175°W.  相似文献   

海水改良LO-CAT法脱除H₂S的再生系统实验研究     

方光静  李春虎  王群  郭姗姗  邢宁宁  冯丽娟  王亮 《中国海洋大学学报(自然科学版)》2013,(9):75-79

在"催化氧化脱硫"与"再生"分开的新型LO-CAT脱硫装置中,以海水为吸收介质,络合铁为载体,针对H2S质量浓度为10g/m3的模拟气进行了海上钻井平台石油伴生气脱除H2S的再生系统实验研究。主要考察了再生系统中碱性液体流速、空气过剩因子(ε)和再生温度等参数对脱硫效果的影响,并对反应产生的固体产物进行了SEM和XRD表征。实验结果分析得出,脱除H2S的最佳再生条件为:液体流速v=8.77mL/min,空气过剩因子ε=90,再生温度T2=45℃。表征得出,产生的固体物质为硫磺,可能含有少量Fex Sy杂质。  相似文献   

碳酸盐岩孔洞型储集体地震反射特征分析   总被引：5，自引：1，他引：4       下载免费PDF全文

曲寿利  朱生旺  赵群  李佩 《地球物理学报》2012,55(6):2053-2061

定量分析碳酸盐岩孔洞型储集体的地震响应特征,对孔洞储集体的预测和刻画研究有着重要意义.基于声波方程,在忽略多次散射的情况下,导出了深层小尺度孤立洞体的地震响应近似解析式,该解析表达式给出了孔洞尺度、充填程度与地震振幅属性之间的关系.分析表明:(1)当孔洞异常体尺度小于地震波长的1/8时,反射波振幅与异常体体积呈近似正比关系;(2)异常体横向上的尺度对反射波振幅的影响主要由菲涅耳半径控制,同时振幅随横向尺度的变化规律受到纵向尺度的影响;(3)异常体纵向上的尺度对反射振幅的影响主要表现为调谐效应,当纵向上的尺度等于调谐厚度(地震波长的1/4)时,反射振幅最强.不同尺度溶洞的数值模拟研究结果以及不同填充物的单洞物理模型试验和溶洞群物理模型试验验证了以上结论的正确性.  相似文献   

低阻区利用地回路标定航空TEM系统的理论研究   总被引：2，自引：2，他引：0       下载免费PDF全文

张爽  陈曙东  于群 《地球物理学报》2012,55(8):2779-2786

本文针对吊舱式航空TEM系统,建立了基于地回路的系统参数标定模型,并分别计算了自由空间模型响应(TLR)、均匀大地模型响应(TER)、地回路与大地耦合模型响应(TELR和TLER).由于TER响应表现为幅度沿测线不变,据此提出通过增加拟合参数的方法实现系统标定,消除了TER响应对标定的影响.TELR和TLER早期响应具...  相似文献   

水氡浓度和环境参数的分层神经网络研究     

潘震宇  卓群  刘仲达  杨婕  丁俊芳 《地震地磁观测与研究》2012,33(3):110-114

采用分层神经网络（LNN）分析地下水的氡浓度,试图给出氡浓度和环境参数之间的函数关系。由于环境（例如：降雨量）对水氡浓度的影响可能是非线性的,与目前时间脉冲响应线性计算方法相比,该方法能够较准确的估计环境参数造成的氡浓度变化。  相似文献