柘林湾表层沉积物中氮和磷的时空分布

于2002年7月19日至12月15日调查了柘林湾表层沉积物中2种形态氮和5种形态磷的时空分布,同时测定了含水量和有机质含量。结果表明,柘林湾表层沉积物中的含水量与有机质、凯氏氮、氨态氮、总磷、岩屑磷和有机磷含量均呈显著正相关关系。凯氏氮的平均含量为1060.3μg·g-1,氨态氮在凯氏氮中所占的比例小于4.0%。总磷的平均含量为526.0μg·g-1,自生钙结合磷含量最高,占总磷的47.5%。氮、磷的平面分布基本呈现出湾内高于湾外、养殖区高于非养殖区的总体趋势。有机质、氮、磷含量的季节变化相对显著,夏季呈上升趋势,秋季有所下降,然后处于上下波动的平衡状态。影响有机质、氮、磷含量季节变化规律的因素主要是养殖动物的种类、陆地排污、鱼虾贝类死亡产生的生物碎屑、水动力和生物扰动。     

柘林湾表层沉积物重金属分布及污染初步评价

研究了柘林湾表层沉积物样品中7种重金属元素的质量分数及分布特征,并对其来源进行了分析。结果显示,调查海区Zn的平均质量分数为113.0μg/g±6.5μg/g、Cr为40.1μg/g±8.5μg/g、Mn为837.9μg/g±168.6μg/g、Cu为24.0μg/g±4.3μg/g、Pb为57.7μg/g±11.3μg/g、Ni为24.4μg/g±5.7μg/g、Fe为3.7%±0.4%。重金属主要来源于陆源风化产物,其质量分数反映了粤东地区的地质特点。分别以沉积物质量和香港环保署公布的标准,对柘林湾表层沉积物重金属污染进行了评估,结果表明:只有Pb在部分站位达到中度污染水平,其它重金属元素则只为轻度污染。     

厦门湾沉积物中磷的形态特征及环境意义

2010年3月在厦门湾采集表层沉积物,应用改进的化学试剂连续分级浸取法(SEDEX)法对其中的弱吸附态磷(Ads-P)、铁结合态磷(Fe-P)、自生磷灰石及钙结合态磷(Ca-P)、碎屑态磷(De-P)和有机态磷(OP)的含量进行了分析测定,结合沉积物的环境参数,讨论了各种形态磷的地球化学行为。Ads-P、Fe-P、Ca-P、De-P、OP和总磷(TP)平均含量分别为9.80μg·g-1、148.69μg·g-1、14.07μg·g-1、136.89μg·g-1、91.97μg·g-1和401.41μg·g-1。研究表明,沉积物中的TP受陆源输入影响较小;Ads-P和Ca-P含量主要源于海区内部生物地球化学过程;De-P、OP和Fe-P主要受陆源输入影响;Ca-P、De-P和OP与重金属(Cu、Pb、Cd和As)具有化学耦合作用,在沉积过程中,可能具有相似地球化学行为。     

渤海湾表层沉积物中的砷与铁、铝、锰等元素的关系

渤海湾沉积物中的砷含量变动在8.8—18.1μg·g~(-1)之间,其中约有三分之一与铝、铁、锰等元素的水合氧化物相结合。本文主要是讨论渤海湾沉积物中的砷与铝、锰、铁等元素间的关系。 为了解沉积物中水合氧化物对砷的关系,除分析沉积物中铁、锰、钛和有机物外,同时也分析了Tamm溶液可提取的铁、铝、锰和砷的含量。     

海洋腐植质的研究——Ⅲ.长江口及东海海水和沉积物中腐植质的分布

本文介绍了测定海水和沉积物中腐植质(HS)含量的方法,并对长江口和东海海水、沉积物中的HS含量进行了调查研究。综合1981—1983年的调查资料,结果表明:124°E以西的长江口海区,表层海水中HS的浓度为150—435μg/L,与盐度S有负相关关系;124°E以东海域,其浓度为100—150μg/L,变化幅度较小。上述海区沉积物中的HS含量为0.416—3.371mg/g,其含量的变化与该海区沉积物颗粒的大小密切相关。     

粤东典型海湾表层沉积物Cd的分布及其潜在生态危害评价*

对粤东海域5个典型海湾64个表层沉积物样进行了重金属Cd含量的测定,分析探讨了其空间分布特征及其主要影响因素,并以南海陆架区Cd含量为背景值计算了粤东5个海湾表层沉积物Cd的潜在生态危害系数。结果显示,柘林湾、汕头湾、汕尾湾、大亚湾和大鹏湾表层沉积物Cd的含量范围分别为0.04—0.58、0.06—6.63、0.06—0.11、0.04—0.20、0.08—0.15 mg·kg?1,其分布表现为：柘林湾养殖区和三百门附近海域以及汕头湾拦沙堤末端海域和好望角附近海域Cd含量高于其他海区,汕尾湾的Cd含量由近岸向外海、西部到东部增加,而大亚湾和大鹏湾外湾含量高。重金属输入和水动力条件是控制 Cd 分布的决定性因素。生态危害评价表明,养殖区、三百门附近海域、拦沙堤末端海域和好望角附近海域Cd污染达到了中等甚至很强的生态危害水平,污染比较严重。来自入海河流携带工业污染物注入、沿岸排污、水产养殖沉降、产业转移人为排放和金属矿床开采释放的 Cd 已造成了近海环境的污染,应当引起相关部门的重视。     

九龙江口沉积物砷含量的分布特征及与环境因子的相关性

采集九龙江河口表层和柱状沉积物样品,对表层沉积物中总砷、不同形态砷和其他重金属元素、有机质含量以及粒径等参数进行测定.分析了柱状沉积物中总砷和各形态砷的含量,结合沉积速率和响应因子,探讨总砷的污染累计特征.结果表明：（1）沉积物中检出的形态砷是As3＋和As5＋,未检出有机砷.（2）表层沉积物中总砷含量范围为10.03～11.29μg/g,河端总砷含量为11.28μg/g,高于海端总砷含量10.42μg/g.As3＋的含量范围为0.84～1.08μg/g,As5＋的含量范围为6.87～8.99μg/g;As5＋含量表现为河端（8.63μg/g）高于海端（7.31μg/g）,As3＋则不明显.（3）有机质含量是影响本区域表层沉积物中砷及其他重金属含量分布的重要因素,粒径与砷及其他重金属显著相关性不强,影响较小.（4）柱状沉积物中总砷含量范围为9.15～13.61μg/g,随深度的变化不明显,人为污染程度较轻.（5）柱状沉积物中As3＋含量介于2.45～5.35μg/g之间,As5＋含量范围为5.58～11.77μg/g,二者含量随深度的增加而降低.     

雷州半岛滨海湿地表层沉积物中重金属含量分布与生态风险评价

采用多元统计方法分析了雷州半岛滨海湿地表层沉积物中重金属的含量、相关性、空间分布特征和来源,并对其生态风险进行了评价。研究区表层沉积物中的Cu、Zn、Pb、Cr、As、Cd和Hg的含量平均值分别为10.29±7.80、47.06±28.47、24.74±10.78、41.70±26.25、7.98±4.73、0.042±0.029和0.020±0.027μg·g-1。Cu、Zn和Cr以及Pb、Cd和Hg为2个强正相关群,第一个群中的重金属元素以自然来源为主,第二个群则兼有人为输入和自然2个来源。重金属含量的高值区主要分布在流沙港、湛江港西部、海安港和雷州湾西部海域。对照美国海洋与大气管理局(NOAA)的生物效应标准,研究区绝大部分海域内的表层沉积物中除As含量在约50%的站位的值在"效应范围低"(effect range low)和"效应范围中等"(effect range median)阈值之间,对底栖生物会偶尔发生负面效应外,其他重金属基本不发生负面效应。重金属总体为低污染程度和低潜在生态风险。应重视人类活动较强的区域如湛江港西部、流沙港、海安港等海区的重金属污染,以避免持续累积至能对生物造成危害的水平。     

绿色石化项目邻近海域表层沉积物PAHs分布及年际变化

为评估绿色石化项目运营前后的环境变化,于2018—2021年连续4年对项目所在地鱼山岛邻近海域的表层沉积物多环芳烃(PAHs)进行了调查。结果表明,PAHs含量为16.9～178.0μg·kg^-1,平均值为75.9±24.0～102.6±41.4μg·kg^-1,4年来整体呈下降趋势,与国内其他海区相比,总体含量较低;各组分平均值为4环PAHs>5环PAHs>3环PAHs>6环PAHs>2环PAHs。调查海域表层沉积物以粉砂为主,PAHs的空间分布受到多种因素的综合影响。调查海域PAHs来源相对稳定,年际差异较小,主要来源于石油、木柴、煤炭等燃烧产物的远距离迁移。依据沉积物质量基准法评价,调查海域沉积物PAHs生态风险水平较低。绿色石化项目在建设期及投产期未引起邻近海域沉积物PAHs的增加,但随着项目持续运营,其对周边生态环境的影响需持续关注。     

海南红树林湿地沉积物中重金属的累积

于2008年在海南典型红树林湿地东寨港、三亚湾和亚龙湾采集沉积物样品,使用原子吸收分光光度法(SOLAAR M6)分析沉积物中Cu、Pb、Zn、Cd和Cr的含量,原子荧光光度法(AFS-8130)分析Hg和As的含量.表层沉积物中Cu、Pb、Zn、Cd、Cr、Hg和As的平均含量分别为14.8±9.2、24.1±9.2、57.9±36.5、0.17±0.10、29.6±20.4、0.08±0.04和9.7±4.4μg·g-1干重(DW),目标化合物(除Cd外)的含量均具有东寨港高、三亚湾次之而亚龙湾低的特点,Cd的含量各区域相近.与国内外其他典型红树林沉积物中重金属的含量相比,本研究区域沉积物重金属含量处于中偏低的水平,这与海南目前开发程度较低、人类活动影响较小相一致.柱状沉积物中Cu、Pb、Zn、Cd、Cr和Hg含量的剖面分布均具有表层稍低、中上层较高和底层相对低的特征,而As的含量呈现表层较高、中上层低和底层相对高的特点.潜在风险分析显示,本研究区域沉积物中重金属(As除外)目前污染较轻,对生态环境影响较小.     

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.