海洋潮汐浪溅区混凝土表面氯离子浓度计算模型   总被引：2，自引：0，他引：2       下载免费PDF全文

蔡荣  杨绿峰  余波 《海洋工程》2014,32(5):25-33

海洋混凝土结构的表面氯离子浓度反映了海洋氯化物环境的腐蚀作用强度,是海洋混凝土结构耐久性分析和定量设计的重要参数。本文依据国内外不同地区的大量自然暴露试验数据,通过数理统计和回归分析,确定了各种海洋环境条件下表面氯离子浓度的统计特征值,分析了海洋潮汐浪溅区混凝土中氯离子的传输机理和积聚规律,揭示了水胶比对混凝土表面氯离子浓度的影响规律,进而综合考虑水胶比、胶凝材料种类和时变特性等因素的影响,建立了海洋潮汐浪溅区混凝土表面氯离子浓度的改进计算模型。结合国内外各种表面氯离子浓度经验模型的预测结果和海洋自然暴露试验的实测数据,对比验证了所建立表面氯离子浓度计算模型的有效性和适用性,为海洋氯化物环境下混凝土结构的耐久性设计和服役寿命分析提供了重要边界条件。  相似文献   

南海南部陆坡区生态要素垂向分布和日变化特征及其与物理环境的关系          下载免费PDF全文

张燕  何蕾  殷克东  姜玥璐  姚景龙  王东晓 《热带海洋学报》2014,(6)

利用2004年5月"实验3"号船在南海南部陆架区观测站(109°40′E,06°05′N)连续48h观测得到的温度、溶解氧浓度、叶绿素浓度数据,分析了观测点的叶绿素和溶解氧的垂向分布、日变化特征及其同水温和盐度等物理环境要素的相关关系。结果表明,叶绿素和溶解氧垂向分布与温度有着显著的负相关关系,与盐度有着显著的正相关关系,溶解氧和叶绿素的日变化与温度和盐度的相关性则不显著,跃层深度和海流等对溶解氧的日变化有一定的影响作用。  相似文献   

Temporal variability of temperature-nitrate relationship in a coastal region     

殷建平  林立  王友绍  杜建伟 《中国海洋湖沼学报》2014,32(4):879-885

The inverse relationship between nitrate and temperature （N-T relationship） has been used to estimate new production from remotely sensed sea surface temperature at the regional or global scale of oceans. This study aimed to develop a time-series model of the N-T relationship from automated, continuous hourly observations over two years on the coast of Halifax, Canada. The model demonstrated time-series variability of the N-T relationship at a coastal station on the Nova Scotia Shelf, with adjusted R2=0.999 4 and RMSE=0.025 7. The maximum residual value was 0.077. The annual temperature variations described a sine curve, and daily, weekly, and monthly variations fluctuated within the normal ranges, controlled by the local climate. The annual variation of nitrate concentration formed nearly a sine curve. Heavy or long- lasting rainfall increased nitrate concentration by 4 to 30-fold in 24 h, and then the increased nitrogen was quickly depleted by phytoplankton growth in 10 to 48 h. In general, biological activity was a key factor in causing nitrate concentration change, dependent mainly on seawater temperature. The power function of the N-T relationship observed in our study area could be used to quickly estimate sea surface nitrate concentration, in combination with temperature data obtained by remote sensing.  相似文献   

Use of calcein and alizarin red S for immersion marking of black rockfish Sebastes schlegelii juveniles     

吕红健  张秀梅  席丹  高天翔 《中国海洋湖沼学报》2014,32(1):88-98

Black rockfi sh Sebastes schlegelii juveniles(30–40 mm total length) were immersed in a range of calcein(CAL) solutions at concentrations ranging from 50 to 250 mg/L and alizarin red S(ARS) solutions at concentrations ranging from 100 to 500 mg/L in fi ltered seawater(salinity 30) for 24 h. Fluorescent marks were detected in otoliths(sagittae, asteriscus), scales, fi n rays(dorsal, pectoral, ventral, anal, and caudal fi n rays), and fi n spines(dorsal, ventral, and anal fi n spines) after a 60-d growth experiment. With the exception of 50–100 mg/L CAL, acceptable marks were produced in the otoliths and fi n spines by all concentrations of CAL and ARS. In particular, marks were clearly visible under normal light in the sagittae, asteriscus, and fi n spines of fi sh immersed in 200–500 mg/L, 300–500 mg/L, and 200–500 mg/L ARS, respectively. Scales and fi n rays had acceptable marks at much higher concentrations(≥50 mg/L CAL, ≥300 mg/L ARS for scales and ≥50 mg/L CAL, ≥200 mg/L ARS for fi n rays). The mark quality was highest(i.e., acceptable marks were observed in all sampled structures after immersion marking) in fi sh immersed in 150–250 mg/L CAL or 300–500 mg/L ARS. In addition, there was no signifi cant difference in survival and growth of marked fi sh compared with controls 60 d post-marking( P 0.05).  相似文献   

Production of dimethylsulfide and acrylic acid from dimethylsulfoniopropionate during growth of three marine microalgae     

刘春颖  高彩霞  张海波  陈烁  邓平  岳新安  郭肖依 《中国海洋湖沼学报》2014,32(6):1270-1279

We measured the concentrations of dimethylsulfide （DMS）, acrylic acid （AA）, and dimethylsulfoniopropionate （DMSP） during growth of three microalgae： Prorocentrum micans, Gephyrocapsa oceanica, and Platymonas subcordiformis. The DMSP, AA, and DMS concentrations in culture media varied significantly among algal growth stages, with the highest concentrations in the late stationary growth stage or the senescent stage. In the stationary growth stage, the average DMSP concentration per cell in P. micans （0.066 5 pmol/cell） was 1.3 times that in G. oceanica （0.049 5 pmol/ cell） and 20.2 times that in P. subcordiformis （0.003 29 pmol/cell）. The average concentrations of AA were 0.044 6, 0.026 9, and 0.003 05 pmol/cell in P. micans, G. oceanica, and P. subcordiformis, respectively, higher than the concentrations of DMS （0.272, 0.497, and 0.086 2 fmol/cell, respectively）. There were significant positive correlations between cell density and AA, DMSP, and DMS concentrations. The ratios of DMS/AA and AA/（DMSP＋AA） in the three algae differed significantly over the growth cycle. In all three microalgae, the DMS/AA ratios were less than 25% during the growth period, suggesting that the enzymatic cleavage pathway, which generates DMS, was not the main DMSP degradation pathway. The changes in the DMS/AA ratio indicated that there was a higher rate of enzymatic breakdown of DMSP in the early growth period and a lower rate during senescence. In all three microalgae, the AA/（DMSP＋AA） ratio （degradation ratio of DMSP） decreased during the exponential growth phase, and then increased. The variations in these ratios can approximately indicate the cleavage mechanism of DMSP at different stages of algal growth.  相似文献   

水流速率对全缘马尾藻幼孢子体生长和生理活性的影响     

黄苑媚  ;刘志刚  ;谢恩义  ;刘付少梅  ;孙宗红 《广东海洋大学学报》2014,(6):45-50

在0、0.5、1、2、4、8 cm/s 等5 种不同水流速率下培养全缘马尾藻（Sargassum integerrimum）幼孢子体,研究水流速率对幼孢子体质量、叶绿素a 含量、SOD 活力、CAT 活力和蛋白质浓度等生理指标的影响.结果表明,以1、2、4 cm/s 流速的幼孢子体质量增长最快,3 种流速的增长差异不具统计学意义（P〉0.05）.在生理指标方面：叶绿素a 含量以1、2、4 cm/s 流速最高,3 种流速的含量差异不具统计学意义（P〉0.05）;SOD 比活性以流速0.5、1、2 cm/s 的活力最低,各组间差异不具统计学意义（P〉0.05）;CAT 比活性以流速1、2 cm/s 的活力最低,组间差异不具统计学意义（P〉0.05）;蛋白质含量以1、2、4 cm/s 流速最大,组间差异具统计学意义（P〈0.05）.水流速率对体质量增长和各生化指标均产生显著的影响,以流速1～4 cm/s 培育全缘马尾藻培幼孢子体较合适.  相似文献   

中国近海浮游植物叶绿素、初级生产力时空变化及其影响机制研究进展     

赵辉  张淑平 《广东海洋大学学报》2014,(1):98-104

综合分析中国近海不同海域浮游植物的时空分布和季节变化特征研究,概述该海域浮游植物叶绿素和初级生产力研究。受复杂的物理环境场、生物地球化学作用等综合影响,不同海域Chl-a和初级生产力具有显著的时空变化特征:空间上,叶绿素浓度表现为近岸高离岸低、离岸海域随纬度增加呈升高趋势;时间上,大体呈现明显的季节变化特征,北部季节特征尤为明显,其中叶绿素浓度及生产力的季节最大值在南海出现在冬季,而在中国北部海域逐渐变化为春季。影响浮游植物生长的主要因素有营养盐、温度、光照、陆源输入、季风、环流、涡旋等,不同海域、不同季节浮游植物生长的限制因子有差异。另外,由于遥感数据的精度以及现场观测航次的频率较低和站位布置较为稀疏影响了上述机制的探讨,因而浮游植物生长的主要调控机制仍待进一步研究。  相似文献   

Simulated Spatial Distribution and Seasonal Variation of Atmospheric Methane over China: Contributions from Key Sources简   总被引：1，自引：0，他引：1  

ZHANG Dingyuan  LIAO Hong  and WANG Yuesi 《大气科学进展》2014,31(2):283-292

We used the global atmospheric chemical transport model,GEOS-Chem,to simulate the spatial distribution and seasonal variation of surface-layer methane （CH4） in 2004,and quantify the impacts of individual domestic sources and foreign transport on CH4 concentrations over China.Simulated surface-layer CH4 concentrations over China exhibit maximum concentrations in summer and minimum concentrations in spring.The annual mean CH4 concentrations range from 1800 ppb over western China to 2300 ppb over the more populated eastern China.Foreign emissions were found to have large impacts on CH4 concentrations over China,contributing to about 85％ of the CH4 concentrations over western China and about 80％ of those over eastern China.The tagged simulation results showed that coal mining,livestock,and waste are the dominant domestic contributors to CH4 concentrations over China,accounting for 36％,18％,and 16％,respectively,of the annual and national mean increase in CH4 concentration from all domestic emissions.Emissions from rice cultivation were found to make the largest contributions to CH4 concentrations over China in the summer,which is the key factor that leads to the maximum seasonal mean CH4 concentrations in summer.  相似文献   

Using hourly measurements to explore the role of secondary inorganic aerosol in PM2.5 during haze and fog in Hangzhou,China     

Roeland Cornelis Jansen  Yang Shi  Jianmin Chen  YunJie Hu  Chang Xu  Shengmao Hong  Jiao Li  Min Zhang 《大气科学进展》2014,31(6):1427-1434

This paper explores the role of the secondary inorganic aerosol （SIA） species ammonium,NH4＋,nitrate,NO3-,and sulfate,SO24-,during haze and fog events using hourly mass concentrations of PM2.5 measured at a suburban site in Hangzhou,China.A total of 546 samples were collected between 1 April and 8 May 2012.The samples were analyzed and classified as clear,haze or fog depending on visibility and relative humidity （RH）.The contribution of SIA species to PM2.5 mass increased to ～50％ during haze and fog.The mass contribution of nitrate to PM2.5 increased from 11％ during clear to 20％ during haze episodes.Nitrate mass exceeded sulfate mass during haze,while near equal concentrations were observed during fog episodes.The role of RH on the correlation between concentrations of SIA and visibility was examined,with optimal correlation at 60％-70％ RH.The total acidity during clear,haze and fog periods was 42.38,48.38 and 45.51 nmol m-3,respectively,indicating that sulfate,nitrate and chloride were not neutralized by ammonium during any period.The nitrate to sulfate molar ratio,as a function of the ammonium to sulfate molar ratio,indicated that nitrate formation during fog started at a higher ammonium to sulfate molar ratio compared to clear and haze periods.During haze and fog,the nitrate oxidation ratio increased by a factor of 1.6-1.7,while the sulfur oxidation ratio increased by a factor of 1.2-1.5,indicating that both gaseous NO2 and SO2 were involved in the reduced visibility.  相似文献   

Distribution of dissolved oxygen and causes of maximum concentration in the Bering Sea in July 2010     

SUN Xiuwu  LIN Cai  CHEN Yong  ZHANG Yuanbiao  WANG Jigang  JI Weidong 《海洋学报(英文版)》2014,33(6):20-27

According to data obtained in the Bering Sea during the 4th Chinese National Arctic Research Expedition, the distribution of dissolved oxygen(DO) was studied, causes of its maximum concentration were discussed, and the relationships between DO and other parameters, such as salinity, temperature, and chlorophyll a were analyzed. The results showed DO concentration ranged from 0.53 to 12.05 mg/L in the Bering Sea basin. The upper waters contained high concentrations and the maximum occurred at the depth range from 20 to 50 m. The DO concentration decreased rapidly when the depth was deeper than 200 m and reached the minimum at the depth range from 500 to 1 000 m, and then increased slowly with the depth increasing but still kept at a low level. On the shelf, the DO concentration ranged from 6.53 to 16.63 mg/L with a mean value of 10.75 mg/L, and showed a characteristic of decreasing from north to south. The DO concentration was higher in the area between the Bering Sea and Lawrence Island and was lower in the southeast and southwest of Lawrence Island at the latitude of 62°N. The formation of maximum DO concentration was concerned with phytoplankton photosynthesis and formation of the themocline. To the south of Sta. B07 in the Bering Sea basin, the oxygen produced by photosynthesis permeated to the deeper water and the themocline made it difficult to exchange vertically, and to the north of Sta. B07, the maximum DO concentration occurred above the themocline due to phytoplankton activities. On the shelf, the oxygen produced by phytoplankton photosynthesis gathered at the bottom of the thermocline and formed the DO maximum concentration. In the Bering Sea basin, the DO and salinity showed a weak negative correlation(r=0.40) when the salinity was lower than 33.1, a significant negative correlation(r=0.92) when the salinity ranged from 33.1 to 33.7, and an irregular reversed parabola(r=0.95) when the salinity was greater than 33.7.  相似文献