广东沿海牡蛎体Cu含量水平及其时空变化趋势

为了解广东沿海 Cu含量水平的时空变化趋势 ,1989～ 1997年实施“南海贻贝观察”对广东沿海 12个地点进行了连续监测。实测数据和有关历史资料综合分析结果显示 ,广东沿海牡蛎体 Cu含量(湿重 )范围为 2 .70～ 352 mg· kg-1,平均值为 94 .1mg·kg-1,总超标率达 35.1% ;局部海区属重污染水平。牡蛎体 Cu含量的空间分布特点呈珠江口海区 >粤西海区 >粤东海区格局 ;Spearman顺位相关分析结果表明 ,1989～ 1997年间 ,广东沿海牡蛎体 Cu含量年际间无明显的趋势性变化。     

3.4万年以来南极斯科舍海古生产力演变及其环境制约

本文通过对南极斯科舍海东南部DC-11岩芯生物硅、有机氮、TFe2O3与有机氮同位素的年代学分析,重建了该海区3.4万年以来古生产力与环境演变历史.研究结果表明,生物硅、有机氮含量与南极温度变化基本一致,暖期高、冷期低;有机氮同位素值与南大洋海冰变化相吻合,暖期小、冷期大,冷期硝酸盐利用率大于暖期.从末次冰期、末次冰消...     

Thermodynamic Characteristics of Tropical Cyclones with RapidIntensity Change over the Coastal Waters of China

In order to investigate the different thermodynamic mechanisms between rapid intensifying (RI) and rapid weakening (RW) tropical cyclones (TCs),the thermodynamic structures of two sets of composite TCs are analyzed based on the complete-form vertical vorticity tendency equation and the NCEP/NCAR reanalysis data.Each composite is composed of five TCs,whose intensities change rapidly over the coastal waters of China.The results show that the maximum apparent heating source Q1 exists in both the upper and lower troposphere near the RI TC center,and Q1 gets stronger at the lower level during the TC intensification period.But for the RW TC,the maximum Q1 exists at the middle level near the TC center,and Q1 gets weaker while the TC weakens.The maximum apparent moisture sink Q2 lies in the mid troposphere.Q2 becomes stronger and its peak-value height rises while TC intensifies,and vice versa.The increase of diabatic heating with height near the TC center in the mid-upper troposphere and the increase of vertical inhomogeneous heating near the TC center in the lower troposphere are both favorable to the TCs' rapid intensification; otherwise,the intensity of the TC decreases rapidly.     

Occurrence of priority pollutants in WWTP effluents and Mediterranean coastal waters of Spain

A comprehensive study aimed at evaluating the occurrence, significance of concentrations and spatial distribution of priority pollutants (PPs) along the Comunidad Valenciana coastal waters (Spain) was carried out in order to fulfil the European Water Framework Directive (WFD). Additionally, PP concentrations were also analysed in the effluent of 28 WWTPs distributed along the studied area. In coastal waters 36 organic pollutants of the 71 analysed, including 26 PPs were detected although many of them with low frequency of occurrence. Only 13 compounds, which belong to four different classes (VOCs, organochlorinated pesticides, phthalates and tributyltin compounds (TBT)) showed a frequency of occurrence above 20% in coastal waters. In the results obtained until now, octylphenol, pentachlorobenzene, DEHP and TBT exceeded the annual average concentration (EQS-AAC), and only TBT surpassed the maximum allowable concentration (EQS-MAC). The most frequent contaminants determined in coastal waters were also present in WWTP effluents.     

电感耦合等离子体质谱法测定含气天然矿泉水中的铬

含气天然矿泉水含有高浓度的HCO;和CO2,其中元素Cr的浓度在电感耦合等离子体光谱(ICP-AES)的检出限附近甚至更低,应用电感耦合等离子体质谱(ICP-MS)测定又容易形成多原子离子40 Ar12C,对52 Cr的测定形成干扰,致使ICP-MS不能直接准确测定含气天然矿泉水中的Cr元素.本文对水样进行前处理,加热煮沸2 min后放置至室温,加入硝酸调节水样酸度为5％,促进HCO3-与H+反应生成大量的CO2迅速释放出来,消除了40Ar12C对52Cr产生的质谱干扰,实现了ICP-MS能够直接准确分析Cr的含量,方法检出限为0.23 ng/mL,加标回收率为92.3％～93.7％,相对标准偏差(RSD)小于10％.此方法简单实用,精确度和准确度能够满足天然矿泉水分析测试的要求,还可同时测定此批前处理水样中的锌铜砷镉铅等痕量元素.     

由多个地震震源机制解求福建东南沿海地区平均应力场

基于震源断层面的空间取向和滑动方向,写出力轴张量在地理坐标系中的表达式,进而给出计算平均力轴张量及主值的方法,即通过求解相应的本征方程得到。对使用多个震源机制解中T,B,P轴参数计算平均应力场的正确性,以许忠淮用滑动方向拟合法反演富蕴、唐山地区平均应力场数据进行计算和验证。选择具有地震构造意义地块或地震带内大量地震的震源机制解研究区域平均应力场。根据福建东南沿海地区47次主要地震的震源机制解,给出了该区应力张量的定量分析结果。该方法物理意义明确,使由大量地震震源机制解资料分析构造应力场的方法走向定量化,并为定量探索区域应力场的整体动态变化成为可能。     

Time dependence of organic matter decay and mixing processes in Framvaren, a permanently anoxic fjord in South Norway

Three different layers have been identified in Framvaren, which has a maximum water depth of 184 m. One oxic layer above the redoxcline at 18–20 m. One anoxic layer from 20 to 100 m which is occasionally ventilated by a flow over the sill (which has a depth of 2.5 m), and finally a stagnant layer below 100 m. Using the release rate of silica from the bottom and measurements of the concentration of HTO it is possible to make some calculations on the annual volume of interleaving in the layers 25–50 m, 50–75 m, and 75–100 m together with the advective flows. Reliable values of the sulfide concentration were obtained by precipitating and weighing HgS together with careful protection of all anoxic water samples with argon. The light yellow color of the precipitate in the depth range 25 to 80 m indicates that the occasional ventilation will cause such reactions as 0.50₂ + H₂S S(colloidal) + H₂O. The elemental sulfur, being stabilized with HS^–, is set free upon the precipitation of HgS. The new data for the concentration of sulfide give an acceptable stoichiometry for the decay reaction of organic matter. This is not the case with the data of Yao and Millero. The mean values for the concentrations of ammonium and phosphate agree with the new data of Yao and Millero. The mol/mol C/N ratio of 10.1 found in trapped material by Naess and coworkers (1988) agrees with the stoichiometry of the dissolved constituents, i.e. C/N = 9.92 ± 0.45. A denitrification reaction is suggested to explain the high values of C/N. The vertical diffusion coefficient at 100 m calculated from the depth profile of silica was 0.92 × 10^–6 m² s^–1 which lies in the range of values given by Fröyland. Finally, the ¹⁴C age of the total dissolved inorganic carbon (Ct) in the water below 90 m was about 1600 years indicating a bioproduction in the period 8000 years B.P. to A.D. 1853 when a channel was opened between the fjord outside (Helvikfjord) and Framvaren.     

Sulfur biogeochemistry and isotopic fractionation in shallow groundwater and sediments of Owens Dry Lake, California

Groundwater and sediment samples (∼ 1 m depth) at sites representative of different groundwater pathways were collected to determine the aqueous speciation of sulfur and the fractionation of sulfur isotopes in aqueous and solid phases. In addition, selected sediment samples at 5 depths (from oxic to anoxic layers) were collected to investigate the processes controlling sulfur biogeochemistry in sedimentary layers. Pyrite was the dominant sulfur-bearing phase in the capillary fringe and groundwater zones where anoxic conditions are found. Low concentrations of pyrite (< 5.9 g kg^− 1) coupled with high concentrations of dissolved sulfide (4.81 to 134.7 mg L^− 1) and low concentrations of dissolved Fe (generally < 1 mg L^− 1) and reducible solid-phase Fe indicate that availability of reactive Fe limits pyrite formation. The relative uniformity of down-core isotopic trends for sulfur-bearing mineral phases in the sedimentary layers suggests that sulfate reduction does not result in significant sulfate depletion in the sediment. Sulfate availability in the deeper sediments may be enhanced by convective vertical mixing between upper and lower sedimentary layers due to evaporative concentration. The large isotope fractionation between dissolved sulfate and sedimentary sulfides at Owens Lake provides evidence for initial fractionation from bacterial sulfate reduction and additional fractionation generated by sulfide oxidation followed by disproportionation of intermediate oxidation state sulfur compounds. The high salinity in the Owens Lake brines may be a factor controlling sulfate reduction and disproportionation in hypersaline conditions and results in relatively constant values for isotope fractionation between dissolved sulfate and total reduced sulfur.     

Ecological thresholds of phytoplankton community across environmental gradients in the harmful algal blooms-frequently-occurring,subtropical coastal waters,East China Sea

Phytoplankton communities can response immediately and directly to environmental changes,and thus have been applied as reliable biotic indicators in aquatic systems.This study provided insights into the relationships concerning ecological thresholds of phytoplankton communities and individual taxon in response to environmental changes in coastal waters of northern Zhejiang Province,East China Sea.Results demonstrated that there existed seasonal variations of phytoplankton community ecological thresholds of which spring being higher than those in summer.As for individual species,Prorocentrum donghaiense and Noctiluca scintillans were identified as the most tolerant and sensitive indicator species in spring and summer,respectively.They exhibited strong indications in response to environmental changes.These findings highlighted that phytoplankton community structure in this region was stable when environmental gradients were below the thresholds of sensitive species,whereas potential harmful algal blooms may occur when environmental gradients exceeded the thresholds of tolerant species.     

厦门邻近海域海洋环境放射性水平及评价

良好的环境质量是厦门成为一个宜居和滨海旅游城市的重要基石。自日本福岛核事故发生和福建省核电站陆续运行之后,厦门邻近海域潜在的核污染风险受到公众和管理部门的关注。本研究测定了2015年2月和8月厦门邻近海域海水和海洋沉积物中主要放射性核素的含量水平,并据此评价了该海域的环境放射性质量状况。结果表明海水中总铀、⁹⁰Sr、²²⁶Ra、¹³⁷Cs处于我国海洋放射性水平变化范围以内,无明显季节差异,其他放射性核素⁵⁸Co、⁶⁰Co、¹³⁴Cs、^110mAg、⁵⁹Fe、⁵⁴Mn、⁶⁵Zn均未检出,海水中⁹⁰Sr和¹³⁷Cs的活度最大值远低于国家海水水质标准限值,海洋沉积物中放射性核素活度水平亦在我国海洋放射性水平变化范围以内。利用我国现有的海洋放射性环境质量评价方法对厦门邻近海域放射性质量状况进行分级评价得出其海水放射性质量为2级,海洋沉...