STUDY ON DETERMINATION OF DIC IN SEAWATER BY COULOMETRIC METHOD

lareODUcrIONThetotalcarbondi0xideisandriportantparametrforestirnatingthespatiotem0ralinorganiccarbontransport,andanthropogeniccarb0ndi0xideincreasesintheoonn.Ap~coulomericednique(MethodG0fASTMD5l3-82)formeasuringDICinanwaterdevelopedbyJohnsonetal.(l985)istheshipkoardmehodchosenfortheglobeocanicinofganiccarb0nsurveyt0bemadeinconjunCtionwiththeW0riddrinCirmlationExperirnentWorklHydrographicProgram(WOCEWHP)andtheJointGobal~nFluxStudy(JGOFS)program(Catherine,G.etal.,l993).Thecruxof…     

KINETICS OF LEAD ADSORPTION BY XIAMEN BAY SEDIMENTS

The kinetics of Pb adsorption in seawater by surface sediments from Xiamen Bay was simulated and the effects of seawater conditions were studied . When water temperature changed from 20 to 30℃, pH from 5 to 8 and salinity from 30 to 4 . the adsorption rate increased by about 50% , one order of magnitude and 5 times, respectively . A negative exponential relation between the adsorption rate and salinity has been found . The adsorption processes can be simulated by the exchange- equilibrium kinetic model . Adsorption rate constant, apparent activation energy and equilibrium adsorptive capacity have been quantitatively determined . The adsorption of Pb by sediments is essentially a chemical action .     

Zn's role in dissolution of al sacrificial anodes

The role of alloying elements in the dissolution of aluminium sacrificial anodes was investigated. The effect of indium on the electrochemical performance of anode and the relationship between indium and impurities, such as silicon and iron, were studied. The distribution of indium in aluminium alloy was detected. The electrochemical behaviour of In-implanted aluminium alloy was also studied. The experimental results indicate that indium activates the surface of aluminium alloy and improves the electrochemical performance of alloy containing more amounts of impurity. Indium combines with silicon and iron. More satisfactory properties were obtained when the alloy's proportion of content of In to that of (Si+Fe) is about 1∶(8∼10). The electrochemical properties of Al alloy, especially the surface activity of the anode were improved by ion implantation. Indium segregates in the alloy. The amount of Si and Fe in the In-rich segregated phase is richer than that in the matrix. It is proposed that the In-rich segregated phase particles activate the surface and promote the dissolution process of the aluminium sacrificial anode.     

Vertical variations and composition of dissolved free amino acid in the seawater of the Yap Trench in the western Pacific Ocean

The composition and concentration of dissolved free amino acid (DFAA) of seawater samples collected in May 2016 from the surface to the hadal zone of the northern region of the Yap Trench were analyzed by pre-column derivatization of o-phthalaldehyde. Results show that the average concentration of DFAA in the study area was 0.47±0.36 µmol/L. In different sampling stations, the concentrations of DFAA with water depth showed complex variation patterns. At the sediment-seawater interface, the concentrations of DFAA in the western side of the trench were obviously higher than that in its eastern side. In the study area, there were no significant correlations between the concentrations of DFAA and the environmental parameters such as concentrations of chlorophyll a (Chl a), dissolved oxygen (DO), pH, and dissolved inorganic nitrogen (DIN), indicating that the concentrations of DFAA in seawater of the trench are affected by many factors, such as photosynthesis, respiration, temperature, pressure, illumination, and circulation. The dominant DFAA are similar in different water layers of sampling stations, including aspartic acid (Asp), glutamic acid (Glu), glycine (Gly), and serine (Ser). The composition of different amino acids, and the relative abundance of acidic, basic, and neutral amino acids might be related to the sources and consumption of various amino acids. Nine pairs of amino acids in the DFAA showed significantly positive relationship by correlation matrix analysis, suggesting that they might share similar biogeochemical processes. The degradation index (DI) of the DFAA in seawater of the Yap Trench could reflect the degradation, source, and freshness of DFAA in the trench to some extents. This is a preliminary study of amino acids from sea surface to hadal zone in the ocean, more works shall be done in different trenches to reveal their biogeochemical characteristics in extreme marine environments.

     

Corrosion Mechanism of 5083 Aluminum Alloy in Seawater Containing Phosphate

As a material with good corrosion resistance,5083 aluminum alloy has a great application prospect in marine environment.In this work,the corrosion characteristics of 5083 aluminum alloy in seawater containing phosphate were investigated with Potentiodynamic Polarization,Electrochemical Impedance Spectroscopy (EIS),Scanning Electron Microscope (SEM),Energy Dispersive Spectroscopy Analysis (EDSA),X-ray Photoelectron Spectroscopy (XPS) and Laser Confocal Microscope.The results indicated that the effects of phosphate in seawater were two-fold.Firstly,phosphate slightly accelerated the corrosion of 5083 in seawater in the early stage of corrosion.HPO_4~(2-)competed with OH~-in the adsorption process on the alloy surface,which weakened the contact between OH~-and Al~(3+)near the interface of the alloy,and inhibited the formation as well as the self-repair of the passive film,thus accelerating the activation dissolution process.Compared with the natural seawater,the charge transfer resistance of 5083 in the seawater containing phosphate decreased faster during the early stage of corrosion,and the corrosion current density i_corr was higher in seawater containing phosphate.On the other hand,the addition of phosphate would not affect the cluster distribution of the second phase of 5083 in seawater,but it changed the composition of the corrosion product layer and had an obvious inhibitory effect on the local corrosion of 5083 in seawater.After 16-day exposure,shallower and more sparsely distributed pits could be observed on the derusted surface of 5083 in the seawater containing phosphate,and the pitting coefficient in the seawater containing phosphate was significantly lower than that in natural seawater.The reduction of pitting tendency could be realized mainly through two ways.First,the HPO_4~(2-)adsorbed on the surface of the passive film in the early stage of corrosion and repeled the corrosive anions such as Cl~-.Second,phosphate participated in the construction of the Ca HPO_4 precipitation film,which acted as a barrier and protection.     

Study on Al-Zn-In Alloy as Sacrificial Anodes in Seawater Environment

Electrochemical properties including conventional electrochemical properties: open circuit potential, polarization potential, electrochemical capacity, morphology of surface dissolution, and the initial polarization properties of Al-Zn-In-Mg-Ti and Al-Zn-In-Si sacrificial anodes are investigated in the sea. The curves of anode output current and work potential with time, the impact of area ratio of cathode to anode on anode output current is discussed, and the initial polarization properties are investigated with cyclic voltammetry(CV) finally. The results show that for the two anodes, the current efficiency got in the sea environment is higher than the data of the 4-day-accelerated test in laboratory and the corrosion morphology is more uniform in the sea. With the same exposed area, the current efficiency of Al-Zn-In-Mg-Ti anode is higher than that of Al-Zn-In-Si in the sea. For both anodes, the current efficiency becomes larger with the increase of the area ratio of cathode to anode. The two anodes can output larger current in strong polarization state. The situation is consistent with the results that small area anode released higher current in the sea trial. The difference rests with that Al-Zn-In-Mg-Ti anode output far greater current than that of the Al-Zn-In-Si under the same polarization potential. The initial polarization property of the Al-Zn-In-Mg-Ti anode is better than Al-Zn-In-Si anode.     

Effect of Temperature on the Acoustic Reflection Characteristics of Seafloor Surface Sediments

Because the sound speeds of seawater and seafloor sediment both increase with temperature,the influence of tempera-ture on the bottom reflection characteristics of seafloor sediments needs to be investigated.Based on the calculation of the temperature-controlled experimental measurement data of typical seafloor surface sediment samples,the temperature-dependent acoustic characteristics,including acoustic impedance,acoustic impedance ratio between surface sediment and seawater,and reflection coefficient,were analyzed.The effective density fluid model was used to analyze and explain the reflection coefficient variation of surface sediments with temperature and predict the dispersion characteristics.Results show that the acoustic impedance of the seabed sediment increases with temperature,whereas the acoustic impedance ratio and acoustic reflection coefficient slightly decrease.The acoustic impedance,acoustic impedance ratio,and acoustic reflection coefficient of sandy,silty,and clayey sediments vary similarly with tem-perature variation.Moreover,the influence of temperature on these acoustic characteristics is independent of detection frequencies.     

威海市桑沟湾及周边海域水质监测与评价

为研究威海市桑沟湾及周边海域水质情况,本文基于桑沟湾及邻近海域30个站位共采集了100个海水样品,分析了研究区海水水质特征,并结合海洋功能区划,采用了单因子标准指数法和综合指数法对研究区海水水质状况做出了评价。研究结果表明：在100个海水样品中,海水良好级水样共有11件,占总数的11%;较好级水样共有89件,占总数的89%,总体上研究区域海水水质满足各功能区要求,适宜水产养殖活动,具备在此海域建设人工鱼礁的水质环境。     

Influence of Seawater Temperature on Phytoplankton Growth in Jiaozhou Bay, China

The phytoplankton reproduction capacity (PRC), as a new concept regarding chlorophyll-a and primary production (PP) is described. PRC is different from PP, carbon assimilation number (CAN) or photosynthetic rate ( P^B ) . PRC quantifies phytoplankton growth with a special consideration of the effect of seawater temperature. Observation data in Jiaozhou Bay, Qingdao, China, collected from May 1991 to February 1994 were used to analyze the horizontal distribution and seasonal variation of the PRC in Jiaozhou Bay in order to determine the characteristics, dynamic cycles and trends of phytoplankton growth in Jiaozhou Bay; and to develop a corresponding dynamic model of seawater temperature vs. PRC. Simulation curves showed that seawater temperature has a dual function of limiting and enhancing PRC. PRC‘s periodicity and fluctuation are similar to those of the seawater temperature. Nutrient silicon in Jiaozhou Bay satisfies phytoplankton growth from June 7 to November 3. When nutrients N, P and Si satisfy the phytoplankton growth and solar irradiation is sufficient, the PRC would reflect the influence of seawater temperature on phytoplankton growth. Moreover, the result quantitatively explains the scenario of one-peak or two-peak phytoplankton reproduction in Jiaozhou Bay, and also quantitatively elucidates the internal mechanism of the one- or two-peak phytoplankton reproduction in the global marine areas.     

Effect of anthropogenic CO2 on the pH and the saturation states of calcite and aragonite of seawater

Growth of phytoplankton, zooplankton and probably most other marine organisms as well, is likely to be affected by the pH of seawater. Growth of calcareous shells and skeletons is less likely to be affected by the saturation states of calcite and aragonite but the dissolution is. The increase of CO₂ in the oceans due to burning of fossil fuel and clearing of forests is decreasing the pH of seawater and the degrees of saturation for calcite and aragonite wordwide. This paper presents the results of the first attempt to estimate the vertical distribution of anthropogenic CO₂, and the decreases in pH and the degrees of saturation of calcite and aragonite in seawater near Taiwan. Most effects are very small except for the possible dissolution of aragonite on the upper continental slope starting around 2050 AD.     

CALCULATION FOR THE DISSOLVED QUANTITIES OF OIL SPILLED AT SEA

Laboratory and field experiments on the dissolution of oil showed that the quantity of the dissolvedoil component in the seawater depends on its solubility, concentration in the pertroleum, and theenvironmental conditions. The vertical oil concentration in calm sea decreases exponentially with depth.The vertical diffusion coefficients and dissolution constants of the N-pareffin from C_(12) to C_(21), totaliso-paraffin, cycle-paraffin and aromatic components in calm sea were calculated, and the oil dissolution in-to seawater was determined to be about 0.52% in 48 h for No. 0 light diesel oil.     

Heterotrophic bacterial flora in aquaculture area around Xuejiadao

From Oct., 1999 to Oct., 2000, the heterotrophic bacterial flora in the aquaculture area around Xuejiadao was investigated. The result shows that the populations of the heterotrophic bacteria are heavier in summer and autumn than those in winter and spring. The average populations in seawater, sediment, the surface of seaweed and the surface of fish are 1.4×10⁴cfu mL⁻¹, 5.4×10⁶cfu g⁻¹, 1.5×10⁶cfu g⁻¹ and 1.8×10³cfu cm⁻², respectively. A total of 301 strains were isolated, among them 259 were Gram-negative. All the Gram-negative bacteria belong to 13 genera and some genera of Enterobacteriaceae. The communities of bacteria are slightly different among the samples. In the body surface of fish, Genus vibrio is dominant. In the remaining samples, dominant genus is Aeromonas.     

广州珠江三角洲海水入侵地区地下水微粒的TEM分析及意义

广州地区地下水咸化现象由来已久,通过透射电子显微镜对广州珠江三角洲地下水的咸化原因进行了研究,并评价了其咸化程度。通过研究广州地区地下水中的微粒特征,包括观察微粒的形貌、结晶程度和化学成分等特征,同时对比现代海水微粒特征,讨论了微粒特征用于地下水咸化原因探究和评价的可行性。研究发现,在咸化程度不同的样品中,微粒中Cl含量不同,没有咸化的样品中难以找到Cl元素,咸化程度越高,微粒中Cl含量可以越高。同时,在受到海水入侵的地下水微粒中发现了具有海洋来源含Sr、Ba等微量元素的微粒,这些微量元素在一定程度上可视为海水的示踪剂,说明该组地下水受到了不同程度的海水浸染。通过透射电子显微镜分析研究了地下水中的微粒,结果表明,该研究区地下水中的微粒继承了海水中的微粒特征,广州市地下水的咸化是由于海水入侵所致,因此,利用微粒特征用于海水入侵的判别分析和评价是可行的。类似地,该方法同样可用于水污染调查以及地下水找矿研究。      

渤海海域渤中凹陷奥陶系碳酸盐岩成岩作用

渤中凹陷奥陶系碳酸盐岩在沉积后经历了漫长的地质改造,不同成岩作用改造使储层极为复杂,因此识别不同成岩环境对潜山储层预测具有一定意义。通过岩石薄片观察、扫描电镜、阴极发光等分析确定研究区奥陶系碳酸盐岩经历了正常海水成岩环境、大气淡水成岩环境和埋藏成岩环境,储层储集空间以溶蚀作用引起的次生孔隙和裂缝为主,物性中等,储层非均质性强。结合区域构造演化,镜下特征,碳、氧同位素分析及包裹体分析表明虽然在大气淡水成岩环境及埋藏成岩环境下均有溶蚀作用发生,但对该区下古生界碳酸盐岩储层影响最大的是古生代-中生代期间大气淡水环境下的表生岩溶作用,构造运动导致地层抬升遭受长时间风化淋滤从而改善了储层物性,而埋藏环境下溶蚀改造对储层物性改造有限;新近纪期间深埋环境下大规模胶结作用是本区奥陶系储层物性降低的主要因素。      

Simultaneous Determination of PIP and POP in Seawater

1INTRODUCTIONInrecentyearsglobalclimatechangehasbeenanissueofbothpublicandscientificconcern.Oceanscover71 %ofearthandplayamajorroleinglobalclimatechange.Phosphorus,asacriticalelement,regulatespri maryproductioninaquaticecosystems.Therefore,thefunctionofphosphorusinoceansystemhasreceivedin creasingscientificinterest(Songetal.,2 0 0 3 ) .PP (particulatephosphorus)isanimportantforminphosphorustransferinseawater(Song,2 0 0 1 ) .Pro portionofPPintotalphosphorus(TP)inseawatervar iesfrom 1 0 …     

Measurement of Labile Cu, Pb and Their Complexation Capacity in Yueqing Bay in Zhejiang Province, China

1　INTRODUCTIONRecently ,thepollutionoftracemetalinseawaterhasbecomeincreasinglyevident.Researchershavefo cusedattentiontotracemetalpresentinvariousexistenceforms ,especiallyorganiccomplexingphases.Theexistencestatesandtransportmechanismofbaytracemetalswerethesubjectofstudybysomere searchers(Gu ,1 991 ;Florence ,1 998;Guo ,1 998;Wells,1 991 ,1 998a ,b ;Wellsetal.,1 998) .Whetherinfreshwaterorseawater,colloidsareclearlydominantfactorsaffectingtheexistencestatesandtransportmechanismoftrac…     

Dimethylsulfide in the South China Sea

ＩＮＴＲＯＤＵＣＴＩＯＮＧｒｅａｔｅｆｆｏｒｔｓｗｅｒｅｄｅｖｏｔｅｄｒｅｃｅｎｔｌｙｔｏｓｔｕｄｙｉｎｇｄｉｍｅｔｈｙｌｓｕｌｆｉｄｅ(ＤＭＳ)ｄｉｓｔｒｉｂｕｔｉｏｎｉｎｓｅａｗａｔｅｒ,ａｓｉｔａｃｃｏｕｎｔｓｆｏｒｔｈｅｍａｊｏｒｐａｒｔｏｆｔｈｅｓｕｌｆｕｒｆｌｕｘｆｒｏｍｔｈｅｏｃｅａｎｓｔｏｔｈｅａｔｍｏｓｐｈｅｒｅ.Ｍｏｒｅｏｖｅｒ,ｉｔｓｏｘｉｄａｔｉｏｎｐｒｏｄｕｃｔｓｉｎｔｈｅａｔｍｏｓｐｈｅｒｅｍａｙｉｎｆｌｕｅｎｃｅｅｎｖｉｒｏｎｍｅｎｔａｌａｃｉｄｉｆｉｃａｔｉｏｎａｎｄ…     

Effects of Bi and Ti on electrochemical property of Al-Zn-In sacrificial anode

The effect of trace elements Bi and Ti on the electrochemical property of aluminium sacrificial anode in seawater was studied. Different amounts of Bi and Ti were alloyed with Al-Zn-In to make 9 types of aluminium sacrificial anodes. Anode closed circuit potential, discharge capacities and current efficiencies were measured in the laboratory. The results show that the effect of Bi is greater than that of Ti. Contribution No. 1869 from the Institute of Oceanology, Academia Sinica.     

Bacterial diversity and community structure in the East China Sea by 454 sequencing of the 16S rRNA gene

The 454 sequencing method was used to detect bacterial diversity and community structure in the East China Sea. Overall, 149 067 optimized reads with an average length of 454 nucleotides were obtained from 17 seawater samples and five sediment samples sourced in May 2011. A total of 22 phyla, 34 classes, 74 orders, 146 families, and 333 genera were identified in this study. Some of them were detected for the first time from the East China Sea. The estimated richness and diversity indices were both higher in the sediment samples compared with in the seawater samples. All the samples were divided by their diversity indices into four regions. Similarity analysis showed that the seawater samples could be classified into six groups. The groups differed from each other and had unique community structure characteristics. It was found that different water masses in the sampling areas may have had some influence on the bacterial community structure. A canonical correspondence analysis revealed that seawater samples in different areas and at different depths were affected by different environmental parameters. This study will lay the foundation for future research on microbiology in the East China Sea.     

EFFECT OF ANTHROPOGENIC CO_2 ON THE pH AND THE SATURATION STATES OF CALCITE AND ARAGONITE OF SEAWATER

unODUcrIONIntereStinthecarboncycehasinamsedbouseoftheobservedincreaseinatmosphericCO,leveIsduetothebumingoffossilfuelandthedearingofforestsre-sultinginlargedhaticandbiogeochdrica1consequenas(ChenandDrake,l986).Experi-mentalstudisofp1antShaveshownresponsesoftypically2O%-4O%highergroWthunderdoubledCo,conditions.Ontheotherhand,theeffedofelevatalCO=conditionsinincreasinggroWth,knownastheCO,fertilimtioneffed,isnotbe1ievedtobetwortantintheoasns(Schimeletal.,1995).Althoughithasbeensuggestedt…