Mortality,growth and fecundity of transplanted mussel and barnacle populations near a pulp mill outfall

The mortality, growth and fecundity of transplanted adult mussel (Mytilus edulis) and barnacle (Balanus glandula) populations near a kraft pulp mill outfall at Port Mellon, British Columbia, were determined. The results indicated that adults of both species were tolerant of bleached kraft pulp mill effluent and survived near the pulp mill outfall. However, the growth rates of both species were retarded when compared with those at the control station. The reproductive activities of the transplanted barnacles were also impaired.     

Approximation approach to the SRM based on root decomposition in the simulation of spatially varying ground motions

The spectral representation method(SRM) is widely used to simulate spatially varying ground motions.This study focuses on the approximation approach to the SRM based on root decomposition,which can improve the efficiency of the simulation.The accuracy of the approximation approach may be affected by three factors: matrix for decomposition,distribution of frequency interpolation nodes and elements for interpolation.The influence of these factors on the accuracy of this approach is examined and the following conclusions are drawn.The SRM based on the root decomposition of the lagged coherency matrix exhibits greater accuracy than the SRM based on the root decomposition of the cross spectral matrix.The equal energy distribution of frequency interpolation nodes proposed in this study is more effective than the counter pith with an equal spacing.Elements for interpolation do not have much of an effect on the accuracy,so interpolation of the elements of the decomposed matrix is recommended because it is less complicated from a computational efficiency perspective.     

渤海湾海河口区沉积物中某些有机组分的环境地球化学特征

河口沉积物中的有机物质和营养成分，部分直接来自陆源，部分则源于河口水体的生物化学作用。在有污染源的地区，水体携带着无机和有机污染物的微粒和某些洛于水的化学物质，它们在海水与河水混合的河口环境条件下发生沉淀；另一些溶解性的营养物质能促使浮游生物繁殖，这些生物死亡后也变为沉淀性的有机物质，致使底质状况恶化，在一定条件下会形成对海洋生物异常有害的腐泥。国内外关于利用底泥的有机组分来探讨河口水域有机污染状况的资料目前还较少，对衡量有机污染或海域富营养化程度的底泥测定项目也研究得很不够。通常只用底泥中的硫化物、有机碳(或COD)和氮等成分的含量来反映底质的状况，但由于海域自然环境状况不同，这些成分的背景含量也有很大的差异，往往难以对比。为对本河口区底泥中的有机组分的含量状况及其与有机污染的关系有较全面的了解，我们分析测定了河口区沉积物中的有机碳(TOC)，有机氮(TON)，总磷(TP)，腐植酸量(HA)、硫化物(S)，烧失量(IL)和阴离子表面活性剂(AS)等成分的含量。沉积物样品主要采于1984年5月。采样站位示于图1。根据站位设置的具体自然条件，可将调查区划分为三个区段：永定新河河口段，系指受潮汐影响的河段，包括A,B,C 和D站；大沽排污口区，系指天津南排污河河口段的E和11b站，以及海河防潮闸外侧的11a站；河口近岸海区，系指上述两区段站位以外的其他调查水域，包括北塘口、大沽口及其口外海域。对沉积物中的有机组分采用下列分析方法：有机碳——重格酸钾氧化法；有机氮——元素仪测定法；硫化物——腆量法；腐植酸——碱液提取法；阴离子表面活性剂——乙基紫光度法和原子吸收间接法(吴景阳等，1986 ；本集吴景阳等另文)；磷——比色法；烧失量——重量法。 本文着重讨论这些有机组分的含量分布特征及其规律。     

Paleomagnetic results from Late Carboniferous to Early Permian rocks in the northern Qiangtang terrane,Tibet, China,and their tectonic implications

Results of a systematic paleomagnetic study are reported based on Late Carboniferous to Early Permian sedimentary rocks on the north slope of the Tanggula Mountains,in the northern Qiangtang terrane(NQT),Tibet,China.Data revealed that magnetic minerals in limestone samples from the Zarigen Formation(CP^z)are primarily composed of magnetite,while those in sandstone samples from the Nuoribagaribao Formation(Pnr)are dominated by hematite alone,or hematite and magnetite in combination.Progressive thermal,or alternating field,demagnetization allowed us to isolate a stable high temperature component(HTC)in 127 specimens from 16 sites which successfully passed the conglomerate test,consistent with primary remnance.The tilt-corrected mean direction for Late Carboniferous to Early Permian rocks in the northern Qiangtang terrane is D_s=30.2°,I_s=-40.9°,k_s=269.0,a_(95)=2.3°,N=16,which yields a corresponding paleomagnetic pole at 25.7°N,241.5°E(dp/dm=2.8°/1.7°),and a paleolatitude of 23.4°S.Our results,together with previously reported paleomagnetic data,indicate that:(1)the NQT in Tibet,China,was located at a low latitude in the southern hemisphere,and may have belonged to the northern margin of Gondwana during the Late Carboniferous to Early Permian;(2)the Paleo-Tethys Ocean was large during the Late Carboniferous to Early Permian,and(3)the NQT subsequently moved rapidly northwards,perhaps related to the fact that the Paleo-Tethys Ocean was rapidly contracting from the Late Permian to Late Triassic while the Bangong Lake-Nujiang Ocean,the northern branch of the Neo-Tethys Ocean,expanded rapidly during this time.     

海底声学底质分类的ELM-AdaBoost方法

基于自适应增强算法（AdaBoost）结合极限学习机（ELM）,通过迭代、调整、优化ELM分类器之间的权值,从而构建了具有强鲁棒性、高精度的ELM-AdaBoost强分类器,增强了现有的ELM分类器的稳定性。以珠江口海区侧扫声呐图像为实验数据,对礁石、砂、泥3类典型底质进行分类识别,该方法的平均分类精度超过90%,优于单一ELM分类器的平均分类精度85.95%,也优于LVQ、BP等传统分类器,且在分类所耗时间上也远少于传统分类器。实验结果表明,本文构建的ELM-AdaBoost方法可有效应用于海底声学底质分类,可满足实时底质分类的需求。     

柴达木盆地西部新生界陆相湖盆碳酸盐岩沉积环境与沉积模式*

利用野外露头、岩心、测井录井和分析化验资料,对柴达木盆地西部(简称“柴西地区”)新生界干柴沟组湖相碳酸盐岩进行了研究,划分了其沉积微相类型,研究了其分布规律,分析其形成环境和控制因素,并建立了相应沉积模式。该区湖相碳酸盐岩在垂向上与碎屑岩频繁互层,湖相碳酸盐岩包括颗粒灰岩、藻灰岩、泥晶灰岩和混积岩4大类11种,划分出了灰泥坪、颗粒滩、藻丘(礁)、浅湖湾以及(半)深湖泥灰岩相等5种沉积微相。通过分析不同碳酸盐岩及其微相时空展布特征,认为其发育主要受控于湖盆构造运动、湖平面变化、陆源碎屑注入、古气候与古水介质条件、古地貌与古水深环境,并在此基础上建立了柴西湖相碳酸盐岩的沉积模式。研究认为柴达木盆地西部干柴沟组沉积时期,湖盆为典型咸化湖盆,构造活动相对稳定,湖平面上升达到峰值。碳酸盐岩主要发育在湖侵期,高频湖平面变化形成了碳酸盐岩与碎屑岩频繁互层。在枯水期,盆地坡折处发育碎屑岩滩坝或三角洲前缘沉积;在湖侵期,盆地坡折处发育了鲕粒滩及藻灰岩,盆地洼陷区发育泥灰岩或灰质泥岩。     

原华北地台早前寒武纪演化的巨旋回

导言原华北地台分布于东经105°以东,北纬30°—40°之间。东南部中、晚元古范围比黄汲清中朝准地台向南延伸稍远,包括淮阳地区以南部分在内(图1)。五十年代开始区域地质调查,七十年代早期在野外认识基础上,作了区域性归纳(程等,1973,1982a,1982b),此外,对矿物相、变质相系、混合岩、花岗岩(程、张,1982;董申保,1982),矿物对的地温地压(张,1981:靳是琴等;1982),氧同位素研究(崔等,1980)。为进一步     

基于GPS基准网的GPS快速静态定位及动态定位方法

介绍基于GPS基准网进行GPS快速静态定位和动态定位的原理和方法。通过计算基准网改正数及其空间分布,利用内插方法求出用户站的模型误差改正数,不仅可以提高GPS整周模糊度的可靠性,而且能够大大改善GPS测量的精度。利用香港GPS基准网2001年3月的实测数据进行了解算,发现香港地区在该时间段内受强电离层活动的影响,采用常规GPS测量方法很难确定整周模糊度。利用传统的快速静态定位方法对香港GPS基准网其中一条边(9.2km) 24h的观测数据按每15min计算,模糊度确定的准确率仅为45%。采用基准网内插改正数后,仅利用L₁的观测数据模糊度确定的准确率提高到100%。点位精度平面位置由2cm提高到5mm,高程精度由4cm提高到3cm。     

POPULATION DYNAMICS AND PRODUCTION OF NEANTHES JAPONIC A (IZUKA)IN A SHRIMP POND

During late February to mid-March, 1991, when mature N. japonica swarmed in the sea surface off Jimo County, Qingdao, seawater containing numerous early embryos was pumped into a nearby 2.7 ha. muddy-sand shrimp pond, where the embryos continued to develop. 800000 Penaeus chinensis seedlings were introduced into the pond on May 30, 1991. Monthly benthic samplings were carried out to determine the population dynamics and production of N. japonica in this atypical environ -ment.The density of N. japonica varied from 0 to 20400 ind./m2. The predation of P. chinensis was considered to be responsible for the mass mortality of N. japonica in June through July, when the worms were 2.2-3.3cm in length and lived in the top 2-4cm sediment. From August to September of 1991, the hottest period in the site, there was no substantial mortality of N. japonica as reported in earlier literature. This was explained by the deeper burrowing of the' worms that protected them from predation by shrimps.Monthly biomass ranged f