Dimethylsulfide (DMS) is generally thought to be lost from the surface oceans by evasion into the atmosphere as well as consumption by microbe.However, photochemical process might be important in the removal of DMS in the oceanic photic zone.A kinetic investigation into the photochemical oxidation of DMS in seawater was performed.The photo-oxidation rates of DMS were influenced by various factors including the medium, dissolved oxygen, photosensitizers, and heavy metal ions.The photo-oxidation rates of DMS were higher in seawater than in distilled water, presumably due to the effect of salinity existing in seawater.Three usual photosensitizers (humic acid, fulvic acid and anthroquinone), especially in the presence of oxygen, were able to enhance the photo-oxidation rate of DMS, with the fastest rate observed with anthroquinone.Photo-oxidation of DMS followed first order reaction kinetics with the rate constant ranging from 2.5×10^-5 to 34.3×10^-5 s^-1.Quantitative analysis showed that approximately 32% of the photochemically removed DMS was converted to dimethylsulfoxide.One of the important findings was that the presence of Hg²⁺ could markedly accelerate the photo-oxidation rate of DMS in seawater.The mechanism of mercuric catalysis for DMS photolysis was suggested according to the way of CTTM (charge transfer to metal) of DMS-Hg²⁺ complex.

研究了代表性大分子有机化合物（MOCs）以及不同分子量的天然有机质（NDOM）对海水中Pt、Pd、Rh（PGEs）的吸附动力学。所选用的大分子有机质包括腐殖酸、卡拉胶、牛血清白蛋白，其分子量均>10 kDa；海水中天然有机质通过切向超滤方法获得，分为分子量 >1 kDa组分与 > 3 kDa组分两种。在实验时间内，除了>1 kDa的NDOM组分对Pt、腐殖酸对Pd的吸附达到平衡外，其余的吸附都没有达到平衡。对于MOCs，其对PGEs的吸附分为两个阶段：前8 h的快速吸附阶段和8 h后的解吸阶段。PGEs离子在MOCs中的分配系数（log₁₀K_d）随实验时间的变化与其动力学的变化趋势一致。但在NDOM对PGEs的吸附中，其log₁₀K_d变化与动力学变化之间存在明显差异。这表明海水中PGEs离子与NDOM的分配行为可能受到多种有机组分的综合控制。PGEs在>1 kDa的NDOM组分中的吸附量及log₁₀K_d都大于>3 kDa的NDOM组分，表明1-3 kDa的NDOM组分可能对PGEs离子和NDOM之间的相互作用有重要影响。现有的动力学模型都不能很好地模拟PGEs与受试有机质之间的吸附过程，表明海水中MOCs或NDOM的胶体结构和形态可能不均匀，PGEs离子与海水中溶解有机物之间的相互作用是一个复杂的过程。

Using semidifferential stripping technique combined with pre-equilibrium complexometric titration, the abnormal phenomena appeared in determining apparent complexation capacity (ACC) are discussed and the improved method for determining ACC is presented in the article.The accuracy of ACC measurement results is tested theoretitelly and experimentally.Based on determination of ACC_Cu, ACC_Pb and ACC_Cd, copper was selected for complexometric titration to determine ACC and the results are proved to be reasonable.ACC_Cu measured in the Haikou Bay surface water is in the range of 166.4-320.2 nmol/dm³, with the mean value of 240.9 nmol/dm³, the maximum value aramd domestic drainage outfall, and the values in other stations are comparatively homogenous.The condition formation constant is in the range of 3.46×10⁷-4.76×10⁸, and the mean value is 1.7×10⁸.Based on the 1:1 comlexing model of copper-natural organic ligand and the toxic concentration limit to marine organisms, seawater self-purification capacity in the Haikou Bay is calculated to be 7.43 μg/dm³.

The unstable state of nitrite results in its very low concentration in seawater, which is below the limit of detection (LOD) of conventional techniques of analysis. Some sensitivity-enhanced methods have been proposed for the determination of nitrite at nanomolar level to illustrate the role of nitrite in the marine nitrogen cycle. However, most of previous reports are not widely accepted, because of their complexity and cost equipment or intensive labor requirement. In this study, a simple automatic system for the determination of nanomolar level nitrite using on-line preconcentration with spectrophotometric detection was described. An Oasis HLB cartridge was adopted to quantitatively enrich the pink-colored azo compound, formed from nitrite via Griess reaction. The cartridge was rinsed with water and ethanol (volume fraction is 55%, the same below), in turn, then eluted by an eluent containing 50% ethanol and 0.25 M(mol/dm³) H₂SO₄, and determined at 543 nm with a 2 cm path-length flow cell. Under the optimized experimental conditions, the calibration curve showed a good linearity in the range of 1.4-85.7 nM, and the LOD (3σ) was estimated to be 0.5 nM. The relative standard deviations of 7 measurements were 4.0% and 1.0% for the samples spiked at 7.1 and 28.6 nM, respectively. The recoveries for the different natural water samples were between 92.2%-108.4%. Each HLB cartridge could be reused for at least 50 times. As compared with other SPE methods, the advantages of this method included the free of interference from salinity variation and less sample consuming. The results of the application of the proposed method to natural water showed good agreement with liquid waveguide capillary cell detection method.

A thorough understanding of the biogeochemical cycling of trace metals in the ocean is crucial because of the important role these elements play in regulating metabolism in marine biotas and thus, the climate. However, a precise and accurate analysis of trace metals in seawater is difficult because they are present at extremely low concentrations in a high salt matrix. In this study, we report an analytical method for the preconcentration and separation of six trace metals, Fe, Ni, Cu, Zn, Cd and Pb, in seawater using a seaFAST automatic solid-phase extraction device, analysis by a triple quadrupole collision/reaction technique with inductively coupled plasma mass spectrometry (ICP-MS), and quantification by the isotope dilution technique. A small volume (10 mL) of seawater sample was mixed with a multi-element isotope spike and subjected to seaFAST procedures. The preconcentrate solution was then analyzed using the optimized collision/reaction cell mode of ICP-MS, with NH₃ gas for Fe and Cd with a flow rate of 0.22 mL/min and He for Ni, Cu, Zn and Pb with a flow rate of 4.0 mL/min. The procedure blanks were 130 pmol/L, 3.0 pmol/L, 6.8 pmol/L, 37 pmol/L, 0.29 pmol/L and 0.42 pmol/L, for Fe, Ni, Cu, Zn, Cd and Pb, respectively. The method was validated using five reference materials (SLRs-6, SLEW-3, CASS-6, NASS-7 and GEOTRACE-GSC), and our results were consistent with the consensus values. The method was further validated by measuring full-water-column seawater samples from the subtropical Northwest Pacific Ocean, and our results demonstrated good oceanic consistency.

Vibrio vulnificus is an opportunistic pathogen widely distributed in estuarine and coastal seawaters. In this study, a culture-free method was developed to rapid detection of V. vulnificus in all seasons, based on loop-mediated isothermal amplification (LAMP) targeting virulent-correlated gene (vcg). The new assay method allows differentiation between the virulent and non-virulent strain of V. vulnificus accurately. This method also allows effective detection of the pathogeny in winter when the bacterium lives in the viable but non-culturable (VBNC) state. A total of 30 costal seawater samples collected in all seasons were used for the evaluation of this method. The results show that the method is sensitive, accurate and convenient.

The specific activities of ²²⁴Ra,²²⁶Ra and ²²⁸Ra were determined by measuring γ-rays of their daughters with HPGe γ spectrometer after preconcentrating Ra isotope' with Mn-fiber adsorption from large volume seawater.The calculating formulas of specific activities of the three nuclides derived.The methods of sample preparation and spectnun analysis were discussed.The advantages of the method are simple,rapid and three nuclides can be determined simultaneously.

本研究通过MC-ICP-MS对在台湾海峡南部采集的2013年春季海水样品进行了U含量及同位素组成的测定分析，探究了U在台湾海峡的地球化学行为。U的各个同位素的平均浓度如下：²³⁸U为3.23±0.14 μg/kg，²³⁵U为（2.34±0.09）×10^-2 μg/kg，²³⁴U为（2.05±0.07）×10^-4 μg/kg。而U同位素比值分别是：δ²³⁴U为155±18，²³⁸U：²³⁵U为138±2。台湾海峡的U含量和同位素比值与开阔大洋基本一致，由此可见，该海峡的U主要由开阔大洋所贡献。将本研究结果与研究海域附近海区的相关结果一同比较，包括九龙江和珠江河口区，厦门湾及南海南部，可以看到台湾海峡U浓度与盐度具有显著的正相关关系（U：S；U=（0.0934±0.0024）×S+（0.0920±0.0615）），表明U在台湾海峡呈现保守性混合。为更好地了解U在台湾海峡的地球化学行为，本文运用了多端元混合模型来比较各个潜在来源的贡献大小。开阔大洋对本研究中U的贡献比例为69-95%，河流为~2%，而大气沉降仅约为0.13%。因此，该模型结果与U浓度和同位素比值分析所得出的结论是一致的，即台湾海峡的U主要由开阔大洋所贡献，并具有保守性的地球化学行为。另外，沉积物间隙水有可能是台湾海峡U的一个重要来源，其可能的贡献比例为3-29%，这与前人基于镭同位素得到的观测结果一致。但后续还需要对台湾海峡沉积物间隙水及其向上覆水体的扩散进行更深入的调查研究。

Dissolved Cu, Pb, Zn and Cd in the I-Iaikou Bay waters were measured to be respectively in the range concentrations of 0.47-1.16μg/dm³, 0.94-2.36 μg/dm³, 1.28-4.83 μg/dm³ and 0.005-0.072 μg/dm³; with respectively average values of 0.78 μg/dm³, 1.36 μg/dm³, 3.14 g/dm³ and 0.03 μg/dm³.Dissolved Cu and Zn concentrations are relatively high at the stations near the Longkun Road Outfall for domestic sewage, the Xiuying Out-fall for industry waste water and the Haidian Island Estuary, but dissolved Pb and Cd concentrations are low in these stations.The values in other stations are comparatively homogenous.Vertical dissolved Cu, Pb and Zn concentrations at the bottom layer are higher than at the surface layer, but dissolved Cd concentration appears to be on the opposite.The measurement results of Cu, Pb, Zn and Cd in suspended particle show that particulate matters in the Haikou Bay seeweter play a role in purifying heavy metals.The study on strong complexed form and non-liable form of dissolved copper show that the ratio of strong complexed form and dissolved form is about 85%,and non-liable form is very low with a value lower than 5 nmol/dm³.Therefore, nipper in the I-Iaikou Bay seawater cannot cause influence on marine organisms.

The English Channel (the Channel) represents a major sink and transport pathway of anthropogenic radioactive ¹²⁹I. Despite this important role, data concerning the distribution of ¹²⁹I in seawater of the Channel are scarce, and most of existing data are restricted to the eastern part of the Channel. The advection and dispersion of ¹²⁹I from the French coast toward the central and further the English coast, especially in the Channel west of Cap de La Hague, are not fully investigated. We present results of iodine isotopes (¹²⁷I and ¹²⁹I) analyses of surface water samples collected along the central English Channel in October, 2010. The data show high ¹²⁹I concentrations between Dover Strait and La Hague, followed by a dramatic drop towards the Celtic Sea and reveal the dispersal of ¹²⁹I towards central and northern part of the Channel. Our observation also implies that the entire British coast is contaminated by ¹²⁹I. ¹²⁹I levels in the westernmost English Channel, close to the English coast, may reflect combined influences from La Hague and Sellafield. Evolution of ¹²⁹I between 2005 and 2010 suggests a strong link to temporal marine discharges from La Hague plant. The discharges from the nuclear reprocessing facility have continued since 2010 and thus an ecological evaluation of ¹²⁹I radioactive hazards in the environment of the Channel may be needed.