Settling particulate matter （SPM） was collected by using sediment traps at four stations in a survey section from Qingdao to Cheju-do, across the Huanghai Sea cold water mass （HSCWM）, in August 2002. The sediment ...Settling particulate matter （SPM） was collected by using sediment traps at four stations in a survey section from Qingdao to Cheju-do, across the Huanghai Sea cold water mass （HSCWM）, in August 2002. The sediment traps were planted in three layers： the upper layer of the thermocline （ULT） above the HSCWM, the lower layer of the thermocline （LLT）, and the bottom layer of water column （BL）. To determine the particle flux, the contents of organic carbon （POC）, organic nitrogen （PON）, total carbon （PC）, and total phosphorous （PP） in SPM were analyzed, and two flux models （Ⅰ and Ⅱ） were improved to calculate the resuspension ratio, with an assumption in Model Ⅰ that the vertical flux of SPM in the LLT equals the net vertical flux of SPM in the whole water column. An X value, i.e., the fraction of the resuspension flux originating from the surficial sediments nearby the sampling station, was deduced from Model Ⅰ to estimate the contribution of lateral currents to the total resuspension flux. The results showed that inorganic particles, fecal pellets, and miscellaneous aggregates were the major types of SPM in the HSCWM, and the contents of POC, PON, PC, and PP all decreased with water depth. A great deal of fecal pellets found in the LLT indicates that the main space producing biogenic SPM is the thermocline, and especially the LLT, where the C/N ratio is lower than that in the ULT. The resuspension ratios, 90%-96% among stations, imply strong impact ofresuspension on particle flux in the BL. These values were not significantly different between the two flux models, suggesting that the hypothesis in Model Ⅰ that the flux in the LLT equaling the net flux to the bottom is acceptable for shallow waters with stratification like the HSCWM. The POC export ratio from the HSCWM ranges from 35% to 68%. It benefits from the short sinking distance in shallow water. The upwelling in the HSCWM enhanced the POC flux through the water mass, and the lateral currents provides up to being greater than 50% ofresuspension flux in the BL according to evaluation of the X value.展开更多
The optimum multiparameter(OMP) method was often used to determine the percentages of water masses based on temperature, salinity and other parameters, like nutrient or dissolved oxygen(DO). There are a number of wate...The optimum multiparameter(OMP) method was often used to determine the percentages of water masses based on temperature, salinity and other parameters, like nutrient or dissolved oxygen(DO). There are a number of water masses in the East China Sea(ECS), a marginal sea of the western Pacific Ocean. However, it is difficult to clarify the proportion of water masses using traditional parameters, such as temperature, salinity, nutrient or DO because of the occurring of intensive biogeochemical processes in the near shore and shelf areas. Here, we reported the use of ^(234)U/^(238)Uactivity ratio embedded in the OMP method. The results indicate that seawater in the northern ECS mainly consisted of the estuarine water of Changjiang River(CEW), Kuroshio water(KW), and Yellow Sea Coastal Current(YSCC). In March 2017, the CEW only influenced the offshore waters shallower than30 m;the KW affected the east edge and the YSCC contributed more than 75% in the northern ECS.展开更多
In this study the molecular formula and structure of lipid constituents of silver carp and bighead carp in middle reaches of Yangtze River were determined by gas chromatography-mass spectrometry. The position of doubl...In this study the molecular formula and structure of lipid constituents of silver carp and bighead carp in middle reaches of Yangtze River were determined by gas chromatography-mass spectrometry. The position of double bounds was identified by the method of double bounds chemical localization. These carps are proved to contain eicosapantaenoic acid (EPA) and decosahexenoic acid (DHA). The contents of EPA and DHA, which were determined by gas chromatography, in silver carp and bighead carp were approximately the same as in tuna and salmon. The contents of EPA and DHA in 100 g wet sample were 0. 187 g, 0. 229 g and 0. 246 g, 0. 325 g respectively, but the cholesterol contents in silver carp and bighead carp were much lower than in tuna and salmon.展开更多
本研究分析了水产养殖和垂钓中饲料、窝料、饵料、水样及水产品中地西泮(Diazepam,DZP)的存在情况,并建立了在线净化-液相色谱串联质谱定量检测方法。结果表明DZP含量在0.5~20.0μg/L间线性良好,相关系数(r^(2))均大于0.999;饵料、水样...本研究分析了水产养殖和垂钓中饲料、窝料、饵料、水样及水产品中地西泮(Diazepam,DZP)的存在情况,并建立了在线净化-液相色谱串联质谱定量检测方法。结果表明DZP含量在0.5~20.0μg/L间线性良好,相关系数(r^(2))均大于0.999;饵料、水样和水产品中定量限(Limit of quantitation,LOQ)分别为1.0μg/kg、0.5μg/L、1.0μg/kg;3种基质中1.0μg/kg、5.0μg/kg和10.0μg/kg 3个浓度水平的加标回收率分别为85.2%~106.5%、82.3%~108.0%、90.7%~116.0%,相对标准偏差(Relative standard deviation,RSD)分别为3.6%~5.1%、2.7%~4.3%、2.1%~2.6%。通过调查发现,7份养殖用饲料中均未检出DZP;28份垂钓中使用的窝料、饵料检出率达66.7%,浓度为2.2~213090.0μg/kg;10份诱鱼剂中均检出DZP,检出率达100%,浓度为637000.0~3471000.0μg/kg;27份水样中DZP检出率达85.2%,浓度为0.4~9.8μg/L和71份淡水鱼中DZP的检出率为54.9%,浓度为0.5~21.8μg/kg。由此可见窝料、饵料及诱鱼剂的使用可能是水体和水产品中DZP频繁检出的重要原因之一,对消费者食用安全和水产养殖行业的健康发展均具有潜在风险,亟需加强DZP监管和监测。展开更多
Precise and sensitive methods for the simultaneous determination of different classes of antibiotics, including sulphonamides, fluoroquinolones, macrolides, tetracyclines, and trimethoprim in surface water, sediments,...Precise and sensitive methods for the simultaneous determination of different classes of antibiotics, including sulphonamides, fluoroquinolones, macrolides, tetracyclines, and trimethoprim in surface water, sediments, and fish muscles were developed. In water samples, drugs were extracted with solid-phase extraction （SPE） by passing 1000 mL of water through hydrophilic lipophilic balanced （HLB） SPE cartridges. Sediment samples were solvent-extracted, followed by tandem SPE （strong anion exchange （SAX） ＋ HLB） clean-ups. Fish muscles were extracted by a mixture of acetonitrile and citric buffer （80：20, v/v） solution, and cleaned by SPE. Liquid chromatography-tandem mass spectrometry （LC-MS/ MS） with multiple reaction monitoring （MRM） detection was employed to quantify all compounds. The recoveries for the antibiotics in the spiked water, sediment, and fish samples were 60.2%-95.8%, 48.1%-105.3%, and 59.8%- 103.4%, respectively. The methods were applied to samples taken from Dianchi Lake, China. It showed that concentrations of the detected antibiotics ranged from limits of quantification （LOQ） to 713.6 ng- L1 （ofloxacin） in surface water and from less than LOQ to 344.8 μg·kg-1 （sulphamethoxazole） in sediments. The number of detected antibiotics and the overall antibiotic concentrations were higher in the urban area than the rural area, indicating the probable role of livestock and human activities as important sources of antibiotic contamination. In fish muscles, the concentration of norfioxacin was the highest （up to 38.5 μg·kg-1）, but tetracyclines and macrolides were relatively low. Results showed that the methods were rapid and sensitive, and capable of determining several classes of antibiotics from each of the water, sediment, and fish matrices in a single run.展开更多
以海洋温差能发电(Ocean Thermal Energy Conversion,OTEC)平台的冷水管为研究对象,根据结构方程和尾流振子方程建立冷水管流固耦合模型,采用有限元方法和Newmark-β法对冷水管涡激振动(Vortex-Induced Vibration,VIV)进行时域分析,并在...以海洋温差能发电(Ocean Thermal Energy Conversion,OTEC)平台的冷水管为研究对象,根据结构方程和尾流振子方程建立冷水管流固耦合模型,采用有限元方法和Newmark-β法对冷水管涡激振动(Vortex-Induced Vibration,VIV)进行时域分析,并在MATLAB软件中开发相应的求解程序。针对冷水管所面临的复杂工况,分别研究外部流场、内部流场、长径比和压载质量等因素对VIV产生的影响。结果表明:随着外流流速和长径比的增大,冷水管横流向VIV模态和振动幅值也发生相应改变,振动强度呈现波动上升;在不发生动态失稳的情况下,内流流速的增加可有效减小冷水管横流向振动幅值,压载质量可大幅减小冷水管自由端的振动位移。展开更多
文摘Settling particulate matter （SPM） was collected by using sediment traps at four stations in a survey section from Qingdao to Cheju-do, across the Huanghai Sea cold water mass （HSCWM）, in August 2002. The sediment traps were planted in three layers： the upper layer of the thermocline （ULT） above the HSCWM, the lower layer of the thermocline （LLT）, and the bottom layer of water column （BL）. To determine the particle flux, the contents of organic carbon （POC）, organic nitrogen （PON）, total carbon （PC）, and total phosphorous （PP） in SPM were analyzed, and two flux models （Ⅰ and Ⅱ） were improved to calculate the resuspension ratio, with an assumption in Model Ⅰ that the vertical flux of SPM in the LLT equals the net vertical flux of SPM in the whole water column. An X value, i.e., the fraction of the resuspension flux originating from the surficial sediments nearby the sampling station, was deduced from Model Ⅰ to estimate the contribution of lateral currents to the total resuspension flux. The results showed that inorganic particles, fecal pellets, and miscellaneous aggregates were the major types of SPM in the HSCWM, and the contents of POC, PON, PC, and PP all decreased with water depth. A great deal of fecal pellets found in the LLT indicates that the main space producing biogenic SPM is the thermocline, and especially the LLT, where the C/N ratio is lower than that in the ULT. The resuspension ratios, 90%-96% among stations, imply strong impact ofresuspension on particle flux in the BL. These values were not significantly different between the two flux models, suggesting that the hypothesis in Model Ⅰ that the flux in the LLT equaling the net flux to the bottom is acceptable for shallow waters with stratification like the HSCWM. The POC export ratio from the HSCWM ranges from 35% to 68%. It benefits from the short sinking distance in shallow water. The upwelling in the HSCWM enhanced the POC flux through the water mass, and the lateral currents provides up to being greater than 50% ofresuspension flux in the BL according to evaluation of the X value.
基金The National Natural Science Foundation of China under contract Nos 41876077 and 41530965the National Key Research and Development Program of China under contract No.2016YFA0601300。
文摘The optimum multiparameter(OMP) method was often used to determine the percentages of water masses based on temperature, salinity and other parameters, like nutrient or dissolved oxygen(DO). There are a number of water masses in the East China Sea(ECS), a marginal sea of the western Pacific Ocean. However, it is difficult to clarify the proportion of water masses using traditional parameters, such as temperature, salinity, nutrient or DO because of the occurring of intensive biogeochemical processes in the near shore and shelf areas. Here, we reported the use of ^(234)U/^(238)Uactivity ratio embedded in the OMP method. The results indicate that seawater in the northern ECS mainly consisted of the estuarine water of Changjiang River(CEW), Kuroshio water(KW), and Yellow Sea Coastal Current(YSCC). In March 2017, the CEW only influenced the offshore waters shallower than30 m;the KW affected the east edge and the YSCC contributed more than 75% in the northern ECS.
文摘In this study the molecular formula and structure of lipid constituents of silver carp and bighead carp in middle reaches of Yangtze River were determined by gas chromatography-mass spectrometry. The position of double bounds was identified by the method of double bounds chemical localization. These carps are proved to contain eicosapantaenoic acid (EPA) and decosahexenoic acid (DHA). The contents of EPA and DHA, which were determined by gas chromatography, in silver carp and bighead carp were approximately the same as in tuna and salmon. The contents of EPA and DHA in 100 g wet sample were 0. 187 g, 0. 229 g and 0. 246 g, 0. 325 g respectively, but the cholesterol contents in silver carp and bighead carp were much lower than in tuna and salmon.
文摘本研究分析了水产养殖和垂钓中饲料、窝料、饵料、水样及水产品中地西泮(Diazepam,DZP)的存在情况,并建立了在线净化-液相色谱串联质谱定量检测方法。结果表明DZP含量在0.5~20.0μg/L间线性良好,相关系数(r^(2))均大于0.999;饵料、水样和水产品中定量限(Limit of quantitation,LOQ)分别为1.0μg/kg、0.5μg/L、1.0μg/kg;3种基质中1.0μg/kg、5.0μg/kg和10.0μg/kg 3个浓度水平的加标回收率分别为85.2%~106.5%、82.3%~108.0%、90.7%~116.0%,相对标准偏差(Relative standard deviation,RSD)分别为3.6%~5.1%、2.7%~4.3%、2.1%~2.6%。通过调查发现,7份养殖用饲料中均未检出DZP;28份垂钓中使用的窝料、饵料检出率达66.7%,浓度为2.2~213090.0μg/kg;10份诱鱼剂中均检出DZP,检出率达100%,浓度为637000.0~3471000.0μg/kg;27份水样中DZP检出率达85.2%,浓度为0.4~9.8μg/L和71份淡水鱼中DZP的检出率为54.9%,浓度为0.5~21.8μg/kg。由此可见窝料、饵料及诱鱼剂的使用可能是水体和水产品中DZP频繁检出的重要原因之一,对消费者食用安全和水产养殖行业的健康发展均具有潜在风险,亟需加强DZP监管和监测。
基金This work was financially supported by the National Natural Science Foundation of China （Grant No. 51178438） and the National Basic Research Program of China （No. 2008CB418201）.
文摘Precise and sensitive methods for the simultaneous determination of different classes of antibiotics, including sulphonamides, fluoroquinolones, macrolides, tetracyclines, and trimethoprim in surface water, sediments, and fish muscles were developed. In water samples, drugs were extracted with solid-phase extraction （SPE） by passing 1000 mL of water through hydrophilic lipophilic balanced （HLB） SPE cartridges. Sediment samples were solvent-extracted, followed by tandem SPE （strong anion exchange （SAX） ＋ HLB） clean-ups. Fish muscles were extracted by a mixture of acetonitrile and citric buffer （80：20, v/v） solution, and cleaned by SPE. Liquid chromatography-tandem mass spectrometry （LC-MS/ MS） with multiple reaction monitoring （MRM） detection was employed to quantify all compounds. The recoveries for the antibiotics in the spiked water, sediment, and fish samples were 60.2%-95.8%, 48.1%-105.3%, and 59.8%- 103.4%, respectively. The methods were applied to samples taken from Dianchi Lake, China. It showed that concentrations of the detected antibiotics ranged from limits of quantification （LOQ） to 713.6 ng- L1 （ofloxacin） in surface water and from less than LOQ to 344.8 μg·kg-1 （sulphamethoxazole） in sediments. The number of detected antibiotics and the overall antibiotic concentrations were higher in the urban area than the rural area, indicating the probable role of livestock and human activities as important sources of antibiotic contamination. In fish muscles, the concentration of norfioxacin was the highest （up to 38.5 μg·kg-1）, but tetracyclines and macrolides were relatively low. Results showed that the methods were rapid and sensitive, and capable of determining several classes of antibiotics from each of the water, sediment, and fish matrices in a single run.
文摘以海洋温差能发电(Ocean Thermal Energy Conversion,OTEC)平台的冷水管为研究对象,根据结构方程和尾流振子方程建立冷水管流固耦合模型,采用有限元方法和Newmark-β法对冷水管涡激振动(Vortex-Induced Vibration,VIV)进行时域分析,并在MATLAB软件中开发相应的求解程序。针对冷水管所面临的复杂工况,分别研究外部流场、内部流场、长径比和压载质量等因素对VIV产生的影响。结果表明:随着外流流速和长径比的增大,冷水管横流向VIV模态和振动幅值也发生相应改变,振动强度呈现波动上升;在不发生动态失稳的情况下,内流流速的增加可有效减小冷水管横流向振动幅值,压载质量可大幅减小冷水管自由端的振动位移。
