The effects of estuarine processes on the fluxes of inorganic and organic carbon in the Yellow River estuary

Riverine carbon flux is an important component of the global carbon cycle. The spatial and temporal variations of organic and inorganic carbon were examined during both dry and wet seasons in the Yellow River estuary. Concentrations of dissolved organic carbon (DOC) and dissolved inorganic carbon (DIC) in the Yellow River during dry seasons were higher than those during wet seasons. The effective concentrations of DOC (C_DOC*) were higher than the observed DOC at zero salinity. This input of DOC in the Yellow River estuary was due to sediment desorption processes in low salinity regions. In contrast to DOC, the effective concentrations of DIC were 10% lower than the DIC measured at freshwater end, and the loss of DIC was caused by CaCO₃ precipitation in low salinity region. Particulate organic carbon (POC) and particulate inorganic carbon (PIC) contents of the particles stabilized to constant values (0.5%±0.05% and 1.8%±0.2%, respectively) within the turbidity maximum zone (TMZ) and showed no noticeable seasonal variations. A rapid drop of PIC and rise of POC occurred simultaneously outside the TMZ due to an intense dilution of riverine inorganic-rich particles being transported into a pool of aquatic organic-poor particles outside the TMZ. Annually, the Yellow River transported 6.95×10⁵ t of DIC, 0.64×10⁵ t of DOC, 78.58×10⁵ t of PIC and 2.29×10⁵ t of POC to the sea.     

大鹏湾海水中氮和磷的分布变化

依据香港特别行政区环境保护署于1999—2007年106个航次的调查资料,结合国家海洋局南海分局于1998—2007年10个航次的调查资料,简要描述和分析大鹏湾海水中可溶性无机氮(DIN)和可溶性无机磷(DIP)含量的多年平均分布变化。结果表明,DIN和DIP含量均夏、冬季较高,而春、秋季较低;受香港和深圳等陆源排放影响,四季吐露港西部和沙头角海区域的DIN和DIP含量普遍比其他区域高;夏季南澳养殖场附近水域的DIN也明显较高,可能与养殖场的饵料投放有关。大鹏湾海水中平均氮磷原子比大于16,而DIN和DIP的平均含量分别为0.069和0.009 mg/L。夏季,由于外海高盐水的入侵,底层水中DIN和DIP含量明显高于表层。9 a调查期间,大鹏湾香港海区海水中DIN和DIP含量的年际变化呈较明显下降趋势,而氮磷原子比的年际变化则呈上升趋势。     

Distribution of Dissolved Inorganic Carbon （DIC） and Its Related Parameters in Seawater of the North Yellow Sea and off the Qingdao Coast in October, 2007

Data on the distribution of dissolved inorganic carbon (DIC) were obtained from two cruises in the North Yellow Sea (NYS) and off the Qingdao Coast (QC) in October, 2007. Carbonate parameters were calculated. The concentrations of DIC are from 1.896–2.229 mmolL⁻¹ in the NYS and from 1.939–2.032 mmolL⁻¹ off the QC. In the southwest of the NYS, DIC in the upper layers decreases from the north of the SP (Shandong Peninsula) shelf to the center of the NYS; whereas in the lower layers DIC increases from the north of the SP shelf to the center of the NYS and South Yellow Sea. In the northeast of the NYS, DIC in all layers increases from the YR (Yalu River) estuary to the centre of the NYS. The distribution of DIC in NYS can be used as an indicator of Yellow Sea Cold Water Mass (YSCWM). Air-sea CO₂ fluxes were calculated using three models and the results suggest that both the NYS and the QC waters are potential sources of atmospheric CO₂ in October.     

Study on the determination of trace methyl mercury in seawater by gas chromatography

Sample seawater containing trace methyl mercury was acidified and adsorbed on hydrosulfo-cotton, washed with hydrochloric acid, extracted by benzene and dried, and then determined by a gas chromatograph with electron capture detector. This method, which can detect a minimum concentration of 0.1×10⁻¹⁰%, can be used to monitor the 10⁻¹⁰% content of methyl mercury in seawater.     

A new spectrophotometric method for measuring COD of seawater

This research studied a new spectrophotometric method for measuring the chemical oxygen demand （COD） of seawater. In this method, the COD was measured using a spectrophotometer instead of titrating with sodium thiosuiphate. The measuring wavelength was selected to be 470 nm, and the COD of three standard glucose solutions （COD = 0.5, 1.5 and 2.5 mgL^-1, respectively） and two seawater samples （from the South Yellow Sea and Jiaozhou Bay） were measured using the spectrophotometric method and titrimetric method respectively. The results showed that the spectrophotometric method was somewhat better than the titrimetric method. The relative standard deviation （RSD） of the spectrophotometric method was less than 2.7%, and the recovery of seawater samples ranged from 96.3% to 103.8%. In addition, the spectrophotometric method has other advantages such as expeditiousness, operation simplicity, analysis automatization, etc. Therefore the spectrophotometric method can be used to measure the COD of seawater with satisfactory results.     

Determination of trace vanadium (V) in seawater and fresh water by the catalytic kinetic spectrophotometric method

A new kinetic spectrophotometric method has been developed for the determination of vanadium (V). The method is based on the catalytic effect of vanadium (V) on the oxidation of weak acid brilliant blue dye (RAWL) by KBrO₃ using the citric acid as activation reagent. The obtained optimum conditions are: c (RAWL) = 1×10⁻⁴ molL⁻¹, c (KBrO₃) = 3×10⁻² molL⁻¹, c (citric acid) = 9×10⁻³ molL⁻¹, pH = 2.50, the reaction time being 7.0 min and the temperature being 25.0°C. Under the optimum conditions, the proposed method allows the determination of vanadium (V) in the range of 0–70.0 ng mL⁻¹ and the detection limit is down to 0.407 ng mL⁻¹. For standard vanadium (V) solution determination, the recovery efficiency is in the range of 98.5%–102% and the RSD ranges from 0.76%–1.25%. Moreover, it is demonstrated that most cations and anions do not interfere with the determination of vanadium (V) under the analytical condition. The new method was successfully applied in the determination of vanadium (V) in fresh water and seawater samples with satisfactory results. Vanadium (V) in the seawater samples from Qingdao offshore was determined using the method and the distribution of vanadium (V) was mapped. Compared with other instrumental analytical methods, the proposed method shows good selectivity, sensitivity, simplicity, lower cost and rapidity. It can be employed on shipboard easily.     

Study on the Determination of Trace Ni（Ⅱ） by the Catalytic Kinetic Spectrophotometric Method

A new kinetic spectrophotometric method has been developed for the determination of trace Ni (II) in natural water.The method is based on the catalytic effect of Ni (II) on the oxidation of weak acid brilliant blue dye (RAWL) by KIO4 in acid medium.The concentration of nickel (II) can be determined spectrophotometrically by measuring the decrease of absorbance of RAWL at λ= 626 nm using the fix-time method.The influencing factors are investigated by the orthogonal experimental design.The obtained optimum analytical conditions are:pH=2.00,c RAWL=5.00×10-5 mol L-1,cKIO 4= 2.00×10-5 mol L-1,the reaction time t=10 min and the temperature T=25℃..Under the optimum conditions,the developed method allows the measurement of Ni (II) in a range of 0-40.0 ng mL-1.The standard deviation of eleven independent measurements of blank reaction is S=3.08×10-3 and the limit of detection is 2.20 ng mL-1.The relative standard deviations (RSDs) in six replicate determinations of 5 ng mL-1 and 8 ng mL-1 Ni (II) are 2.87% and 1.11%,respectively.Moreover,the experiments show few cations and anions can interfere with the measurement of Ni (II).The recovery efficiencies of this method are in a range of 97.0%-102.5% in freshwater samples.But there is a decreasing effect,which is about 0.2 times the added Ni (II) in seawater medium.After reasonable calibration this processing method is used for the determination of Ni (II) in seawater samples successfully.The results show this developed method has high accuracy and precision,high sensitivity,large range of linearity and high speed.The method can,therefore,be employed at room temperature.     

Comparison on soil carbon stocks between urban and suburban topsoil in Beijing,China

The urban population and urbanized land in China have both increased markedly since the 1980s. Urban and suburban developments have grown at unprecedented rates with unknown consequences for ecosystem functions. In particular, the effect of rapid urbanization on the storage of soil carbon has not been studied extensively. In this study, we compared the soil carbon stocks of different land use types in Beijing Municipality. We collected 490 top-soil samples （top 20 cm） from urban and suburban sites within the Sixth Ring Road of Beijing, which cover approximately 2400 km2, and the densities of soil organic carbon （SOC）, soil inorganic carbon （SIC）, and total carbon （TC） were analyzed to determine the spatial distribution of urban and suburban soil carbon characteristics across seven land use types. The results revealed significant differences in soil carbon densities among land use types. Additionally, urban soil had significantly higher SOC and SIC densities than suburban soil did, and suburban shelterbelts and productive plantations had lower SIC densities than the other land use types. The comparison of coefficients of variance （CVs） showed that carbon content of urban topsoil had a lower variability than that of suburban topsoil. Further findings revealed that soil carbon storage increased with built-up age. Ur- ban soil built up for more than 20 years had higher densities of SOC, SIC and TC than both urban soil with less than 10 years and sub- urban soil. Correlation analyses indicated the existence of a significantly negative correlation between the SOC, SIC, and TC densities of urban soil and the distance to the urban core, and the distance variable alone explained 23.3% of the variation of SIC density and 13.8% of the variation of TC density. These results indicate that SOC and SIC accumulate in the urban topsoil under green space as a result of the conversion of agricultural land to urban land due to the urbanization in Beijing.     

A New Method for the Non-destructive Determination of Fish Freshness by Nuclear Imaging

A new method for determining the freshness of harvested carp using nuclear imaging technology is presented. This research attempted to determine the freshness of carp by measuring the radioactive area increase （RAI） value of fish. The carp samples were maintained under refrigerated condition for 12 d, and RAI and total volatile base nitrogen （T-VBN） values were determined during the storage. The results showed that the RAI value increased with the T-VBN content during the storage. Also, there is a significant correlation between T-VBN content and RAI value of the carp kept in refrigerated condition. The results of this study suggest that the RAI value could be utilized to evaluate rapidly the freshness of carp.     

Comparison of HTC method and UV/persulphate method to determine colloidal organic carbon in seawater

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Study on kinetics of cathodic reduction of dissolved oxygen in 3.5% sodium chloride solution

Electrochemical reduction of dissolved oxygen in seawater on metals is of great importance for corrosion studies. The present paper studied cathodic reduction of dissolved oxygen on Q235 carbon steel in 3. 5% sodium chloride(NaCl)solutions by cyclic voltammetry(CV), electrochemical impedance spectroscopy(EIS), rotating disk electrode(RDE)and rotating ring-disk electrode(RRDE). The cyclic voltammetric results demonstrated the cathodic process on Q235 carbon steel in O2-saturated 3. 5% NaCl solution contains three reactions:dissolved oxygen reduction, iron oxides reduction and hydrogen evolution. The peak potential of oxygen reduction reaction(ORR)is-0. 85 V vs Ag/AgCl, 3 molL-1 KCl. The E1S results indicated that the ORR occurring on Q235 carbon steel is a 4-electron process and that no finite diffusion is caused by the intermediate of H2O2 produced by ORR. The RDE and RRDE voltammograms confirmed the EIS results and it was found that the number of transferred electrons for ORR was nearly 4, I. E. , dissolved oxygen reduced to water.     

Characteristics of carbonaceous aerosol in a two-week campaign at Ny-lesund

The concentrations of organic carbon(OC)and elemental carbon(EC)in total suspended particle(TSP)were investigated at Ny-Alesund,Svalbard in atwo-week campaign.The levels of OC and EC are 0.86±0.27μgm~(-3)(mean±standard deviation)and 0.19±0.10μgm~(-3),respectively.Back trajectory analy-sis of air masses arriving at Ny-lesund reveals that long-range transport of pol-luted air play insignificant role in OC and EC levels,to which the potential influ-ence of the local contamination were ascribed.The average OC/EC ratio is 5.41,suggesting the presence of the secondary organic aerosols.The estimated second-ary organic carbon(SOC)in TSP is 0.59μg/m~3,accounting for 64% of the totalorganic carbon.     

Influential factors on the exchange rate of dissolved inorganic nutrients at the sediment-water interface in Jiaozhou Bay, China

Incubation experiments are carried out to study the exchange rates of dissolved inorganic nutrients including silicate, phosphate, ammonium, nitrite, and nitrate (vSiO3-Si, vPO4-P, vNH4-N, vNO2-N and vNO3-N) at the sediment-water interface in the Jiaozhou Bay. Major factors influencing the exchange rates are discussed in detail, which include the dissolved inorganic nutrient concentrations in porewater (Cpw), water and clay contents, and grain size of the sediments (CH2O, Cclay and GSsed). The results may provide insight into the dynamics of nutrient transport and the environmental capacity of nutrients in Jiaozhou Bay, and should be beneficial to solving the problems caused by excessive nutrient input this area.     

Influential factors on the exchange rate of dissolved inorganic nutrients at the sediment-water interface in Jiaozhou Bay,China

Incubation experiments are carried out to study the exchange rates of dissolved inorganic nutrients including silicate, phosphate, ammonium, nitrite, and nitrate （^vSiO3-Si,^vPO4-P, ^vNH4-N, ^vNO2-N and ^vNO3-N） at the sediment-water interface in the Jiaozhou Bay. Major factors influencing the exchange rates are discussed in detail, which include the dissolved inorganic nutrient concentrations in porewater （Cpw）, water and clay contents, and grain size of the sediments （CH2O, Cclay and GSsed）. The results may provide insight into the dynamics of nutrient transport and the environmental capacity of nutrients in Jiaozhou Bay, and should be beneficial to solving the problems caused by excessive nutrient input this area.     

Characteristics of carbonaceous aerosol in a two-week campaign at Ny-Alesund

The concentrations of organic carbon (OC) and elemental carbon (EC)in total suspended particle (TSP) were investigated at Ny-(A)lesund, Svalbard in a two-week campaign. The levels of OC and EC are 0.86 ±0.27 μgm-3 (mean±standard deviation) and 0. 19±0.10 μgm-3 , respectively. Back trajectory analysis of air masses arriving at Ny-(A)lesund reveals that long-range transport of polluted air play insignificant role in OC and EC levels, to which the potential influence of the local contamination were ascribed. The average OC/EC ratio is 5.41,suggesting the presence of the secondary organic aerosols. The estimated secondary organic carbon (SOC) in TSP is 0.59 μg/m3 , accounting for 64% of the total organic carbon.     

Determination of butyltin in seawater by gas chromatography with flame photometric detector

INTRODUCTIONTheincreasinglydiverseuseofbutyltininindustry ,agricultureandaquaculturehasledtocon cernregardingtheimpactanddangerofthesealkyltincompoundsonenvironment.Muchattentionhasbeenpaidbyworldscientistsinthelastthirtyyearstotheproblemsoforganotincontamination .Theuseoforganotin ,particularlytributyltinbiocides,asshippaintcomponentcausescontaminationofharbourandcoastalaquaticbiota.Tributyltinandbutyltinareveryeffectiveagainstmarinefoulingorganismsbutalsopollutethemarineenvironmentandar…     

基于GIS和USLE的东圳库区土壤侵蚀量预测研究

运用GIS、遥感技术与USLE模型相结合预测东圳库区流域土壤侵蚀量,利用GIS平台建立东圳库区基础地理数据库,以10×10m为栅格单元对库区进行离散化,在GIS空间分析功能支持下,结合USLE土壤侵蚀预测模型,根据合适的USLE因子算法生成栅格图层,通过图层运算,预测了东圳库区土壤侵蚀量,进而标识库区土壤侵蚀严重区域,为库区非点源污染控制及水土流失治理提供定量依据,并通过建立实用的泥沙输移比模型结合水文监测数据,对预测结果进行验证。根据USLE方程,采用改进后的SDR方程,预测的渡里流域年输沙量与流域实际监测得到的年输沙量仅相差14.08%,说明本文采用USLE方程模拟流域土壤侵蚀结果可信,可定量评价、拟定水土保持措施方案。     

ICPAES法测定超基性岩中13元素的方法研究

采用HCl-HNO3-HF-HCl O4,HCl-HNO3-HF-H2SO4敞口,HCl-HNO3-HF-HCl O4密闭和HNO3-HF密闭消解4种方法溶矿,利用电感耦合等离子体发射光谱(ICP-AES)测定,建立了超基性岩石中钾、钠、钙、铝、铁、钛、锰、钴、镍、铬、钒、锶、锌等元素的同时测定方法。对电感耦合等离子体发射光谱仪测定的最佳仪器条件及分析谱线进行了选择,并对镁基体的影响进行了研究,采取标准溶液中加入适量的镁作基体匹配,以消除基体影响。实验结果表明:采用HNO3-HF密闭溶矿,具有检出限低、灵敏度高,操作简便、快速等突出优点。该方法测定值与推荐值基本吻合,分析方法的精密度满足《地质矿产实验室测试质量管理规范》的要求。     

硝酸银络合法浓缩金枪鱼鱼油多不饱和脂肪酸的研究

以金枪鱼鱼油混合脂肪酸为材料 ,利用硝酸银络合法浓缩其中的多不饱和脂肪酸 (PU FA) ,主要考察了搅拌时间和硝酸银浓度对产品得率和EPA和DHA含量的影响 ,并测定了产品的理化指标和脂肪酸组成。研究结果表明 :搅拌时间为 6 0min ,硝酸银浓度为 4mol/L时得到的产品得率为 18.0 3% ,浓缩产品中的EPA和DHA的质量分数分别为 9.78%和 86 .0 7% ,总质量分数达95 .85 % ,过氧化值为 7.35mmol/kg ,碘值 2 6 0 8.9g/kg。     

沂沭断裂带地热资源管理信息系统的建设

山东省沂沭断裂带地热资源管理信息系统是以Mapinfo为平台,通过建立地热信息数据库及软件二次开发,实现对山东沂沭断裂带地区地热资源空间多源信息数据的有效管理。该系统可为政府部门做好地热资源开发与管理工作提供空间信息技术支持。