海鱼AChE监测海水有机磷农药的可行性研究

有机磷农药(OPs)对乙酰胆碱酯酶(AChE EC 3.1.1.7)具有专一性抑制作用,因此AChE常作为淡水和土壤OPs污染的特异性标识物(biomarker).本文在海水背景下,通过测定两种有机磷农药(马拉硫磷和甲基对硫磷)对海洋鱼类-鲈鱼[Lateolabrax japonicus(cuvier)]脑组织AChE的抑制效应,分析了海鱼AChE监测海水OPs的可行性.结果显示,抑制时间为20min时,抑制程度达到相对稳定;在低浓度OPs抑制下,纯酶液比粗酶液表现出更好的敏感性,对马拉硫磷和甲基对硫磷的灵敏度分别达到0.28μg*L-1和0.2μg*L-1;在一定浓度范围内,AChE活力对OPs具有显著的线性响应.研究表明,利用鲈鱼AChE指示和监测海水OPs的微污染是完全可行的.     

基于FIA和光学原理的酶传感器检测海水甲基对硫磷

将乙酰胆碱酯酶(acetylcholinesterase,AChE)传感器与流动注射系统(flow injection analysis system,FIA)相结合,通过光学方法测定固定化酶受农药抑制后的残余活性,对海水中微量甲基对硫磷进行定量分析。该系统的适宜工作条件为:温度30℃;固定化酶的用量0.05 U;载液流速0.45 mL/min;进样时间20 min;底物(碘化硫代乙酰胆碱)溶液浓度0.100 mol/L,注射量100μL。在0.1~100μg/L之间,农药浓度的对数值与固定化酶活性的抑制率之间具有良好的线性关系(r=0.995 3)。利用该系统检测含甲基对硫磷分别为0.8μg/L和5.0μg/L的模拟海水样品,获得了较好的准确度和精密度,平均相对误差和变异系数均小于10%。     

有机磷农药对胆碱能系统影响研究进展

有机磷农药具有高效、低毒等特点被广泛应用于农业生产,其残留对生物和人类的健康构成了潜在的威胁.由于有机磷农药主要通过影响胆碱能系统的活性发挥其神经毒性作用,因此本文综述了有机磷农药对胆碱能系统中乙酰胆碱脂酶、胆碱乙酰转移酶、毒蕈碱型受体和烟碱型受体产生的影响及可能的致毒机理.有机磷农药首先抑制乙酰胆碱脂酶的活性产生神经...     

海水中甲基对硫磷和马拉硫磷的气相色谱法测定

基于《水质有机磷农药的测定－气相色谱法》,结合海水中农药的含量低可降解等特点,对检测海水中甲基对硫磷和马拉硫磷的方法进行了改进。本方法改用电子捕获检测器和玻璃填充柱用的担体,固定液;及色谱条件。实验室的验证结果表明：修改后的检测方法检测灵敏度可以满足对海水中甲基对硫磷和马拉硫磷较低含量的检测要求。     

阳离子交换树脂吸附石墨炉原子吸收法测定海水中痕量铜、铅、镉

用阳离子交换树脂吸附石墨炉原子吸收法测定海水中痕量Cu,Pb,Cd。实验选定了最佳的测定条件。结果表明,在弱碱性条件下,Cu,Pb,Cd能同时被阳离子交换树脂定量吸附。方法的相对标准偏差<3﹪,样品加标回收率93﹪～102﹪,检出限分别为Cu 0.06μg/L,Pb 0.06μg/L,Cd 0.005μg/L。本法操作简便、快速、无干扰、无污染,已用于海水中铜、铅、镉的分析,取得了令人满意的结果。     

海水有机磷农药实时数据采集系统设计

为实现海水中有机磷浓度现场监测,采用由单片机和工控机组成的海水有机磷农药实时数据采集系统的设计.给出了由PIC单片机构成的采集控制模块硬件设计原理和软件设计方法,工控机的程序流程和浓度的算法.     

沙滩水体中溶解性石油烃的降解及吸附研究

以海水体系和海水-砂体系作为对比,研究了沙滩水体中溶解性石油烃的降解及吸附作用。实验结果表明,1d内海水中石油浓度的降低主要是由于砂的快速吸附作用,3d以后生物对石油烃的降解作用逐渐占据优势。两种体系中降烃菌数量及石油浓度的变化曲线表明,砂对油的快速吸附显著降低了海水中石油污染物的浓度,使得海水含砂体系中石油降解菌的数量远高于海水体系。海水中石油污染物的降解符合一级动力学模式,当含砂体系中砂的粒径不同时,石油污染物降解的半衰期可由海水体系的31.9d缩短到22.4d和19.5d。系统中砂的存在有利于海水中石油污染物的去除,有约20%的石油污染物被吸附到砂上,然而这种去除是物理去除。     

深海沉积物中微量DNA的提取及应用

采用化学裂解和酶解相结合的方法，进行了深海沉积物中微量DNA的提取，并采用DNA吸附树脂进行纯化。结果表明，该方法能有效地去除沉积物中的腐殖酸等抑制剂，每克湿重沉积物样品可得到DNA约16μg，回收率可达95％，所得到的DNA分子片段均在23kb左右，纯化后的DNA可直接应用于各种分子生物学操作。利用细菌16SrDNA通用引物对所提取的深海沉积物DNA进行了PCR—RRJ及系统发育分析，各主要细菌类群均能检出，证实该方法可以应用于深海等极端环境中微生物的多样性调查、系统发育分析以及特殊功能基因的筛选，同时还可应用于环境样品中生物量的半定量估计。     

金枪鱼(Katsuwonus pelamis)碎肉蛋白降压肽的酶解制备及活性研究

以血管紧张素转换酶(ACE)抑制率为指标,通过正交试验L9(34)确定碱性蛋白酶(Alcalase)对金枪鱼(Katsuwonus pelamis)碎肉蛋白的最佳酶解条件,利用D101大孔树脂建立了酶解物的脱盐工艺,利用超滤、葡聚糖凝胶(G-25)色谱和反相-高效液相色谱(RP-HPLC)分离降压肽,并确定其纯度,利用氨基酸序列分析和ESI-MS鉴定纯化多肽的结构。结果表明,碱性蛋白酶酶解金枪鱼碎肉蛋白制备降压肽的最佳酶解条件是:pH 9.5,酶用量1.5%,酶解温度50°C,酶解时间5h;D101大孔吸附树脂脱盐工艺条件为:上样浓度10 mg/mL、上样流速1.5 BV/h、解吸剂为75%乙醇;酶解物经超滤和Sephadex G-25分离获得一个纯度较高的四肽,经氨基酸序列分析和ESI-MS鉴定结构为Phe-GlyGly-Val(FGGV),ESI-MS检测给出分子离子峰m/z 379.50([M+H]+)。利用碱性蛋白酶酶解并经超滤和色谱技术制备的金枪鱼碎肉蛋白降压肽具有良好的ACE抑制活性,可作为降压药物、保健食品或添加剂进行开发。     

桑沟湾农药残留及贝毒对海洋环境质量影响和主要食用贝类健康风险评估

根据2009-04—2010-02隔月6个航次桑沟湾9个调查站位贝类养殖区有机氯(OCPs)、有机磷(OPPs)农药残留和麻痹性贝毒(PSP)的调查资料,分析了它们在该海域海水中、表层沉积物中和主要贝类(栉孔扇贝、太平洋牡蛎和菲律滨蛤仔)体内的含量水平,就农药残留及贝毒污染对海洋环境质量的影响进行综合评价和类别划分,并对主要食用贝类中农药残留和贝毒的暴露水平进行健康风险评估。结果表明,桑沟湾贝类养殖区海水质量、沉积物质量和养殖贝类质量水平范围为1~2级,平均分别为2级、1级和1级,养殖生态环境综合质量水平为2级;总体上,该海域海洋环境综合质量处于良好水平,贝类产区生态环境质量为1类区(清洁区)。即该海域农药残留及贝毒污染对海洋环境质量影响较小或无明显影响。另外,针对食用桑沟湾贝类水产品的消费人群进行了农药残留及贝毒污染的健康风险评估,结果表明调查人群食用贝类中OCPs中的HCHs和DDTs、OPPs中的马拉硫磷和甲基对硫磷、PSP的日摄入量分别为0.75,2.11,0.19,0.09和1.22μg/(人·d),其摄入量低于ADI的推荐限值,因此桑沟湾主要食用贝类中农药残留及贝毒污染的健康风险处于安全范围。     

海上大直径钢管桩打桩过程中桩周土强度弱化研究

海上大直径钢管桩打桩过程中,桩周土体受到强烈扰动而发生强度弱化,掌握桩周土体强度弱化规律对于准确预测打桩过程、保证工程安全具有重要意义。为研究土体强度弱化规律,开展了环剪试验模拟打桩对桩周土体的扰动,测试土体强度随剪切速率的变化规律,建立了描述土体强度弱化规律的拟合公式,引入到打桩分析软件中。研究结果表明：土体的强度折减程度不仅与土体本身的性质有关还受到土体的埋深和剪切速率的影响,埋深越深土体强度折减程度越低,剪切速率越高土体强度折减越高,在打桩分析中可采用这里推荐的线性折减方法来模拟不同深度处土体强度的折减规律。     

Phylogenetic diversity and phenotypic characterization of cultivable bacterioplankton isolated from polar oceans

A set of 27 marine planktonic bacteria isolated from the polar regions was characterized by 16S rDNA sequencing and physiological and biochemical testing. More than half of these bacteria were positive for caseinase, gelatinase and 13-glucosidase, and could utilize glucose, maltose or malic acid as carbon source for cell growth. Twelve isolates expressed nitrate reduction activities. Except for one antarctic isolate BSwlO175 belonging to Actinobacteria phylum, these isolates were classified as γ-Proteobacteria, suggesting that γ-Proteobacteria dominated in cultivable marine bacterioplankton at both poles. Genus Pseudoalteromonas was the predominant group in the Chukchi Sea and the Bering Sea, and genus ShewaneUa dominated in cultivable bacterioplankton in the Prydz Bay. With sequence similarities above 97%, genus Psychrobacter was found at both poles. These 27 isolates were psychrotolerant, and significant 16S rDNA sequence similarities were found not only between arctic and antarctic marine bacteria （ 〉 99% ）, but also between polar marine bacteria and bacteria from other aquatic environments （ ≥ 98.8% ）, including temperate ocean, deep sea, pond and lake, suggesting that in the polar oceans less temperature-sensitive bacteria may be cosmopolitan and have a bipolar, even global, distribution at the species level.     

Estimation of Sediment Properties during Benthic Impact Experiments

Sediment properties, such as water content and density, have been used to estimate the dry and wet weights, as well as the volume of sediment recovered and discharged, during benthic impact experiments conducted in the Pacific and Indian Oceans. The estimates show that the weights of dry (355-1332 t) and wet sediment (1651-4888 t) recovered during the experiments, are not only a function of the total duration and distance covered during the experiment, but also depend on water content and density of the sediment. Estimation of dry sediment and its volumetric ratio in the discharge, are key parameters for calculating the discharged volume. The estimated volume of wet sediment recovered (1427-4049 m 3 ) as well as discharged (2693-6951 m 3 ) during the experiments, provide important inputs to evaluate the sediment resettlement and migration. Using these estimates, the average depth of excavation on the seafloor, can also been calculated. However, the stages of sediment recovery and discharge are expressed differently in some of the experiments. In order to standardize these, different stages have been identified, and definitions of certain terms have been suggested, for use in the future. The methods of calculating different properties, as well as weight and volume of discharged sediment are described in the paper for use in other applications concerning deep-sea discharges.     

A Tidal Flow Model for the Gulf of Kachchh, India

A vertically integrated model has been used to study the tidal circulation and currents in the Gulf of Kachchh along the west coast of India. The model is fully nonlinear and uses a semiexplicit finite difference scheme to solve the basic hydrodynamic equations on a staggered grid. The model is forced by prescribing the tides along the open boundary of the model domain. The flow is simulated both with and without the presence of the proposed tidal barrage across the Hansthal Creek in the Gulf of Kachchh. The results show a considerable change in the behavior of the tidal flow in the presence of the barrage.     

利用中国GF-3卫星SAR和HY-2A卫星微波散射计的首次台风联合定量观测

<正>The typhoon,as a mature tropical cyclone that develops in the western part of the North Pacific Ocean with high wind speed and heavy rainfall,is one of the most lethal and costly of natural disasters for the densely populated countries of East Asia.It can be easily detected by space-borne sensors operated at microwave,visible or infrared bands(Liu et al.,2014).Synthetic Aperture Radar(SAR)is     

离子交换—原子吸收光谱法测定海水中痕量铜、铅、锌、镉、铁、锰

本文介绍了用国产D401型螯合树脂分离富集海水中铜、铅、锌、镉、铁、锰等痕量元素,并用原子吸收光谱仪测定其含量的方法。讨论了各元素的分离条件选择及干扰元素的影响,并与溶剂萃取法的结果作了比较。各元素检测的定量下限为:铜0.5μg/L、铅0.1μg/L、锌1.0μg/L、镉0.01μg/L、铁2.0μg/L、锰2.0μg/L。方法精密度在4—8％之间,回收率为90—102％。     

Biogeochemistry of Mangrove Soil Organic Matter: a Comparison BetweenRhizophoraandAvicenniaSoils in South-eastern Brazil

Soil core samples fromRhizophora mangleL. andAvicennia schauerianaStapf & Leech forests from south-eastern Brazil were analysed for their total organic matter content and their sugars, amino acid and amino sugars composition. Organic carbon and nitrogen contents were higher inAvicenniathan inRhizophorasoils. The contribution of sugars and amino acids to the total organic carbon pool was constant with depth inRhizophorasoils whereas inAvicenniasoils it increased. Spectral distribution of sugars and amino acids showed a dominance of Ca-affine monomers, particularly acidic amino acids, and the sugar arabinose. Biogeochemical indicators derived from ratios of individual sugar and amino acid monomers confirm previous studies which showed that organic matter in both soils is mainly of mangrove origin. The results further suggest accumulation of organic matter inRhizophorasoils and a continuing degradation of organic matter inAvicenniasoils. The latter may thus release more nutrients to adjacent ecosystems thanRhizophorasoils.     

A review of orange roughy Hoplostethus atlanticus fisheries,estimation methods,biology and stock structure

Orange roughy Hoplostethus atlanticus are unusual fish. They form dense aggregations that have fuelled lucrative fisheries at great depths (600–1 400 m), especially off Namibia, New Zealand and Australia. They are thought to be very long-lived (>100 years, maturity at 22 – 40 years), and to have exceptionally low natural mortality (M = 0.045–0.064 year^?1) and slow growth rates (K = 0.055–0.070 year^?1). In addition, they spawn large eggs and have low fecundity. These factors combine to make orange roughy highly susceptible to overfishing; most stocks are below 30% of pristine levels. Assessments are obtained from indices of catch rate and trawl, acoustic and egg surveys. Acoustic estimates are the most direct, but are confounded by the species' low target strength (?50 to ?53 dB)–attributable to the wax-filled swim bladder. Extracellular wax esters are stored in abundance and comprise mostly mono-unsaturated fatty acids, with low concentrations of the ω-3 fatty acid family. This unusual composition (resultant from the species' diet) ensures neutral buoyancy. Stock separation has been inferred mainly from biological studies, but genetic studies have also found differences among stocks within New Zealand and Australia. Deep-water habitat may be damaged by trawling operations and may take many years to recover, so in some quarters there is a call for a portion of suitable habitat to be set aside for preservation. Although Namibian orange roughy are shallower, smaller and younger than those in other stocks, the Namibian fishery sustained high catches for only a few years before quotas were reduced, from 12 000 to 1 875 tons. Three management lessons are suggested for developing orange roughy fisheries based on the Namibian experience: (1) imposition of catch limits during exploratory fishing; (2) starting the acoustic surveys earlier in the fishery, if possible; (3) greater reliance on trends in catch rate until a survey series has been established.