The divergent environmental characteristics of permanently-open,seasonally-open and normally-closed estuaries of south-western Australia

This study has compared the environmental characteristics of the basins and saline lower reaches of the tributaries of eight estuaries on the south coast of Western Australia, which differ in their degree of connectivity with the ocean. Although four estuaries between 115.1° and 121.8° E along that coast remain permanently open to the ocean, the others only become open when the volume of river discharge is sufficient to breach the prominent sand bars at their mouths, which occurs annually following heavy winter and early spring rainfall in some estuaries (seasonally open) and infrequently in others (normally closed). Estuaries to the west of 118.5° E are predominantly permanently open, e.g. Oyster Harbour, or seasonally open, e.g. Broke, Irwin and Wilson inlets, whereas those further east, e.g. Wellstead Estuary and Hamersley, Culham and Stokes inlets, where annual rainfall and thus discharge are much lower, only become open after exceptionally heavy discharge. In permanently and seasonally-open estuaries, pronounced haloclines and oxyclines are present in the narrow rivers but not the wide basins where the waters are subjected to wind-driven mixing. The extent of cyclical seasonal fluctuations in environmental conditions differed markedly among the three seasonally-open estuaries and between years in one of those systems. These differences reflected variations in the relationship between the volume of fluvial discharge, which is determined by a combination of the amount of local rainfall, catchment size and extent of clearing of native vegetation, and the amount of intrusion by marine waters, which is largely controlled by the size and duration of the opening of the estuary mouth. The mean seasonal salinities in the basins of the three normally-closed estuaries increased over three years of very low rainfall to 64 in the deepest of these estuaries (Stokes Inlet) to 145 in Hamersley Inlet and to 296 in the shallowest estuary (Culham Inlet). These results demonstrate that the environmental characteristics of estuaries on the south coast of Western Australia differ markedly, even among those of the same type, e.g. seasonally-open estuaries or normally-closed estuaries.     

Scleractinian cold-water corals in the Gulf of Cádiz—First clues about their spatial and temporal distribution

This paper presents the first compilation of information on the spatial distribution of scleractinian cold-water corals in the Gulf of Cádiz based on literature research and own observations (video footage, sediment samples). Scleractinian cold-water corals are widely distributed along the Spanish and Moroccan margins in the Gulf of Cádiz, where they are mainly associated with mud volcanoes, diapiric ridges, steep fault escarpments, and coral mounds. Dendrophyllia cornigera, Dendrophyllia alternata, Eguchipsammia cornucopia, Madrepora oculata and Lophelia pertusa are the most abundant reef-forming species. Today, they are almost solely present as isolated patches of fossil coral and coral rubble. The absence of living scleractinian corals is likely related to a reduced food supply caused by low productivity and diminished tidal effects. In contrast, during the past 48 kyr scleractinian corals were abundant in the Gulf of Cádiz, although their occurrence demonstrates no relationship with main climatic or oceanographic changes. Nevertheless, there exists a conspicuous relationship when the main species are considered separately. Dendrophylliids are associated with periods of relatively stable and warm conditions. The occurrence of L. pertusa mainly clusters within the last glacial when bottom current strength in the Gulf of Cádiz was enhanced and long-term stable conditions existed in terms of temperature. Madrepora oculata shows a higher tolerance to abrupt environmental changes.     

七带石斑鱼胚体和卵黄囊期仔鱼的发育

本实验对七带石斑鱼胚体、卵黄囊期仔鱼形态发育的过程进行观察,研究其发育特征.结果表明:(1)七带石斑鱼受精卵在水温会(27.77±1.05)℃,盐度32条件下,胚胎发育从胚体形成至孵出仔鱼历时约22h 10min.(2)仔鱼卵黄囊在孵化2d后消失,油球消失于孵化后第6 d,卵黄囊依照先卵黄、后油球的顺序被吸收.吸收速度为先快后慢.(3)初孵仔鱼在孵化后一天时间内生长迅速.之后速度减缓.(4)仔鱼的营养可概括为内源性营养一混合营养一外源性营养阶段.     

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锦州25—1区块探井钻井实践与认识

锦州25—1油田是渤海湾近年钻探发现的大型油田。锦州25—1区块先后钻了十多口探井,在钻井作业中遇到上部井眼扩大严重、井径不规则、井垮、起下钻遏阻卡、电测作业遏阻、电测井底沉砂较多、井漏等复杂情况。通过对锦州25—1区块前面几口探井钻井中出现的问题进行认真分析,研究了锦州25—1区块的地层压力剖面分布。经过不断的总结与措施改进后,在后面的探井钻井作业中做到了起下钻顺利,上部井径扩大率较小,未出现井垮情况,电测一次到底,钻井作业生产时间大幅度提高,为锦州25—1油田的生产井钻井积累了宝贵的经验。     

基于ERDAS的SPOT5卫星影像正射校正方法研究

海岛海岸带卫星遥感调查与评价项目以高分辨率卫星遥感影像数据为基础。项目区块地形有一半为山地和丘陵,地形起伏较大,常规的几何校正难以消除因地形起伏引起的影像几何变形,必须进行正射校正。根据现有数据特点和项目要求,提出了可行的正射校正流程,基于SPOT5物理模型对融合影像进行正射校正,实验校正结果完全满足精度要求。     

黄斑篮子鱼去毒相关基因的克隆与肝脏组成型表达分析

从基因水平探讨海洋鱼类对海洋藻毒素的去毒分子机理。采用RT-PCR法成功克隆了黄斑篮子鱼Siganus oramin肝脏I时相代谢酶细胞色素P450 1A(CYP1A)、II时相代谢酶alpha型谷胱甘肽S-转移酶(GSTA)和rho型谷胱甘肽S-转移酶(GSTR)、热休克蛋白70 (HSP70)、alpha 1型钠钾ATP酶(ATP1A1)及β-肌动蛋白(beta-actin, ACT)基因cDNA核心序列,序列分别长879 bp、582 bp、588 bp、660 bp、749 bp和554 bp。序列同源性分析发现,属鲈形目的黄斑篮子鱼CYP1A、GSTA和GSTR与同属鲈形目的牙鲆Paralichthys olivaceus、欧洲鲽Pleuronectes platessa、真鲷Pagrus major、鲤形目的斑马鱼Brachydanio rerio 相应氨基酸序列同源性较高,CYP1A和GSTA与非洲爪蟾(两栖类)、鸡(鸟类)、小鼠、大鼠和人(哺乳类)相应氨基酸序列同源性低,这可能与鱼类I、II时相去毒酶基因承担水环境毒素去毒代谢的特殊功能有关;而HSP70、ATP1A和β-肌动蛋白在鱼类、两栖类、鸟类、哺乳类中均有较高的同源性,这可能与这些基因在机体中承担的最基本的生命功能相关。应用半定量RT-PCR的方法,以β-肌动蛋白作为外参照,在指数期增长范围内分别得到了CYP1A、GSTA、GSTR、HSP70和ATP1A1 mRNA与β-肌动蛋白mRNA (%)的比值,确定黄斑篮子鱼肝脏去毒相关基因的组成型表达水平。其中,黄斑篮子鱼肝脏CYP1A、GSTA和GSTR基因组成型表达相对较高,HSP70和ATP1A1基因组成型表达相对较低,这可能与不同基因在黄斑篮子鱼海洋藻毒素去毒分子机理中承担的作用相关,为海洋藻毒素在海洋鱼类中的积聚及代谢去毒分子机制的研究提供了相关数据。     

能效渔业状态下津市西湖生态因子与浮游植物密度的灰关联模型{GM(I,N)}

利用灰色系统理论,于2004—2008年5—8月份对能效渔业状态下津市西湖水质状况进行了实时采样研究,并计算了浮游植物密度与透明度、水温、水深、溶解氧、pH、NH4-N、NO3-N、NO2-N、PO4-P、TP、TN、NH4-N/PO4-P、TN/TP和浮游动物共14个生态因子的关联度、关联序。结果表明,透明度、水温、水深、溶解氧、pH和浮游动物(毛里湖)或TN(西湖)是影响浮游植物增殖态势的最重要的环境变量。提取如上变量和浮游植物密度作为建模要素,构建了津市西湖生态因子与浮游植物密度的灰关联模型{GM(I,N)},经作图分析表明,模型值和实测值具有较好的对应峰,表明模型的有效性及在预测上有较高的参考价值。P元素在西湖的营养限制性基本得到消除,水体N/P比被调控到了较好状态。     

壳聚糖酶基因在解脂耶氏酵母中的表达及重组酶性质研究

为构建高效表达壳聚糖酶工程菌株,以Microbacteriumsp.基因组为模板扩增壳聚糖酶基因,目的基因与表达载体pINA1317连接构建重组质粒,重组质粒NotⅠ酶切线性化后转化解脂耶氏酵母Y.liPolytica Po1h。所得结果为PCR扩增得到约1000bp的特异性片段,序列分析表明含有壳聚糖酶全长基因,开放阅读框801bp,编码266个氨基酸残基。转化子酶活力为10.4U/mL,是原菌株酶活力的3.15倍。重组蛋白经DEAE-Sepharose FF分离纯化,达到电泳纯,SDS-PAGE显示单一条带,分子量约41kDa。重组酶反应最适温度为45℃,最适pH为5.6,Km和Vmax分别是0.926mg/mL和6.15U/mL。质谱分析酶解产物主要为三糖和五糖。实现了壳聚糖酶在解脂耶氏酵母中的分泌表达,为壳聚糖酶的工业化生产奠定了理论基础。     

南海海域红斑后海螯虾(Metanephrops thomsoni)的分子识别与群体遗传分化

利用16S rRNA基因序列分子识别红斑后海螯虾,然后对海南附近海域(18°30′-19°00′N,111 °30′-112°30′ E)、北部湾口海域(15°41′ N,110°40′ E)和南沙群岛海域(5°20′-5°29′N,110°09′-111°26′E)三个地理群体进行ITS1的扩增测序.16S rRNA基因序列的结果表明所取样本准确;三个地理群体分别得到616-623bp、619bp和614bp的ITS1全长序列,A、G、T、C含量平均分别为22.3％、29.4％、17.8％和30.6％;其中562个保守位点,39个多态位点.ML和NJ聚类分析显示三个地理群体共聚为三个大支,其中海南群体有群体分化.表明红斑后海螯虾三个地理群体分化极其显著,且海南群体具有相对高的遗传多样性.