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1.
The Al—basic sacrificial anode is widely used to protect steel construction from corrosion in seawater, but is not suitable
for protecting steel in freshwater. In the estuary area, seawater and freshwater mix and different seawater salinity can be
formed in different mixing sites between freshwater and seawater. Based on the requirements of the Shengli Petroleum Administrative
Bureau of China, the effect of seawater salinity on electrochemical properties of Al—basic anode was studied under laboratory
conditions by the method given in National Standard GB 4948-85 (China Starndard Bureau, 1985). No obvious effect was found
when seawater salinity was 30 to 10, but obvious effect on anodic open circuit potential, closed circuit potential and current
efficiency was found when seawater salinity was 5. These values are lower than those given in the National Standard.
Contribution No. 2681 from the Institute of Oceanology, Chinese Academy of Sciences. This study is a major project (Ky85-11-5)
and a key project (A14920416) of the Chinese Academy of Sciences, and also received support from the Shengli Oil Field. 相似文献
2.
A study on the nonspecific immunity of Litopenaeus vannamei ever inhabiting freshwater and seawater was carried out at different molt stages by comparing their total hemocyte count(THC) and respiratory burst(RB) and activity of phenol oxidase(PO), nitric oxide synthase(NOS) and lysozyme(LY). Two-way ANOVA showed that salinity and molt stage independently affected THC and RB and the activity of PO, NOS and LY of juvenile L. vannamei significantly(P 0.05). The THC and RB and the activity of NOS gradually increased from the post-molt stages(A and B) to the pre-molt stages(D0–D3), which were common in shrimps inhabiting freshwater and seawater. The activity of PO peaked at the inter-molt stage(C), and touched the lowest at the post-molt stage in freshwater and pre-molt stage in seawater. The activity of LY was stable over the molt cycle. The RB and the activity of PO, NOS and LY of juvenile L. vannamei were significantly lower in freshwater than in seawater; whereas THC was significantly higher in freshwater than in seawater(P 0.05). It was concluded that the post-molt stage(especially stage A) was critical to shrimp culture, which should be intensively attended when L. vannamei was cultured in freshwater. 相似文献
3.
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. 相似文献
4.
马士德 《中国海洋湖沼学报》1989,7(3):271-273
The effect of barnacles on corrosion of low alloy (16Mn) steel was studied by immersing steel panels in seawater at Zhonggang.Qingdao, for 41 months. It was found that the secondary attachment on this kind of steel by barnacles had less effect on its corrosion while the primary attachment had a greater effect; that different seasons have different effects on the form and extent of local corrosion in this steel, and that primarily attached barnacles cause more serious local corrosion in high breeding seasons when there are more attachments. 相似文献
5.
《中国海洋湖沼学报》2017,(4)
Estuaries are environments where freshwater and seawater mix and they display various salinity profiles.The construction of river barrages and dams has rapidly changed these environments and has had a wide range of impacts on plankton communities.To understand the dynamics of such communities,researchers need accurate and rapid techniques for detecting plankton species.We evaluated the diversity of eukaryotic plankton over a salinity gradient by applying a metagenomics tool at the Nakdong River estuary in Korea.Environmental samples were collected on three dates during summer and autumn of 2011 at the Eulsukdo Bridge at the mouth of that river.Amplifying the 18 S rDNA allowed us to analyze 456 clones and 122 phylotypes.Metagenomic sequences revealed various taxonomic groups and cryptic genetic variations at the intra-and inter-specific levels.By analyzing the same station at each sampling date,we observed that the phylotypes presented a salinity-related pattern of diversity in assemblages.The variety of species within freshwater samples reflected the rapid environmental changes caused by freshwater inputs.Dinophyceae phylotypes accounted for the highest proportion of overall diversity in the seawater samples.Euryhaline diatoms and dinoflagellates were observed in the freshwater,brackish and seawater samples.The biological data for species composition demonstrate the transitional state between freshwater and seawater.Therefore,this metagenomics information can serve as a biological indicator for tracking changes in aquatic environments. 相似文献
6.
The Henry’s Law constant (k) for phosphine in seawater was determined by multiple phase equilibration combined with headspace gas chromatography. The effects of pH, temperature, and salinity on k were studied. The k value for phosphine in natural seawater was 6.415 at room temperature (approximately 23°C). This value increases with increases in temperature and salinity, but no obvious change was observed at different pH levels. At the same temperature, there was no significant difference between the k for phosphine in natural seawater and that in artificial seawater. This implies that temperature and salinity are major determining factors for k in marine environment. Double linear regression with Henry’s Law constants for phosphine as a function of temperature and salinity confirmed our observations. These results provide a basis for the measurement of trace phosphine concentrations in seawater, and will be helpful for future research on the status of phosphine in the oceanic biogeochemical cycle of phosphorus. 相似文献
7.
对企鹅珍珠贝稚贝、中贝和成贝在降低盐度的海水中存活状态进行了观察和研究。在水温20~23℃,以不同盐度梯度(8、12、16、20、242、8、30和33)的海水暂养稚贝并定时检查,在广东的四个海区,对盐度变化时中贝及成贝的养殖成活率进行了观察。结果表明:盐度低于16的3个组,稚贝在60h内全部死亡,盐度20~24海水中,稚贝虽只有部分死亡,但活力较差;稚贝在14的海水中4h后转入正常海水,可全部存活,而超过8h后再移入正常海水的稚贝会陆续死亡;在盐度18海水中,稚贝一直未分泌足丝附着,而移入正常海水,6h就有小苗附着;大万山岛附近海域在雨季盐度可降至20以下,6~9月不适合养殖,而其它实验点可以通过深吊避免海水盐度变化造成企鹅珍珠贝死亡。 相似文献
8.
于2005年8月对湛江港附近海域潮间带的海水、表层沉积物和贝类体内的重金属进行了分析,结果表明:海水中的砷优于海水水质Ⅰ类标准,而汞、铜、锌、铅、镉均有不同程度的污染,其中铜、铅、镉污染较为严重,均劣于海水水质Ⅳ类标准;表层沉积物中砷的含量低于全国海岸带背景值,而汞、铜、锌、铅、镉均高于全国海岸带背景值,其标准指数分别为1.35、1.66、1.50、2.08、3.10,汞、铜略高于海洋沉积物质量标准第一类标准,有轻微污染,砷、锌、铅均低于海洋沉积物质量标准第一类标准,未受污染,而镉略高于海洋沉积物质量标准第二类标准,环境受镉污染。各元素在各站点的分布没有规律性。牡蛎和蛤仔体内各重金属含量均优于海洋生物污染评价标准和人体消费卫生标准,其卫生质量良好。 相似文献
9.
As a multi-branch estuary system, the Yangtze Estuary presents distinctive characteristics of hydrodynamic processes through co-action among river runoff, tides, wind-waves, and gravitational circulation. To study the pathways of flushing water along all of the estuary's branches and analyze their differences, especially those due to the influence of seawater intrusion and discharge variations, a free surface flow modeling suite TELEMAC-MASCARET involving passive tracers was applied to the Yangtze Estuary and the adjacent waters. The open boundary conditions were provided by the Nao.99 b model(Matsumoto et al., 2000), which was calibrated using observed velocity and salinity data obtained in March 2002. The water age, which was used as the diagnostic tool to study the flushing efficiency of the water body across the estuary, was solved by additional advection-diffusion-reaction equations implemented in the TELEMAC modeling system. The transport properties were investigated under different river discharge scenarios, which represented seasonal impacts; aspects relating to the influence of tide, surface wind stress, and density-induced circulation on age were also investigated. Model results showed that river runoff is one of the dominant factors influencing the spatial distribution of the mean age, while tidal force is another important factor. The horizontal freshwater age distribution demonstrated similarity compared with the salinity distribution; the vertical age distribution resembled the stratification pattern of salinity in all branches where stratification persists. An experimental numerical simulation of tracing saltwater age from the lower reaches of the estuary was conducted, and implicated the connectivity with transport processes of freshwater from upstream. Additionally, a particle tracking algorithm was used to analyze the dynamic characteristics of the four passages. The South Passage and South Channel were found to be significant as main water flow passages, while salinity intrusion in the North Branch was found to cause a return flow that partially joins the South Branch flushing water. 相似文献
10.
Studies of community structure and seasonal dynamics of planktonic copepods in saline-alkaline ponds 总被引：1，自引：0，他引：1
Abstracts Species abundance and seasonal succession of copepods in saline-alkaline ponds were studied in Zhaodian Fish Farm, Gaoqing County, Shandong Province, from 5 April 1997 to 1 September 1998. The results indicated that in the conditions of salinity ranging from 1.36 to 20 g/L, total alkalinity changing from 2.4 to 7.2 mmol/L and pH 8-9, zooplankton in saline-alkaline ponds was composed of freshwater salt-tolerated species or halophile species, some of which are halobiont species and usually occurs in freshwater. In our study, copepods were predominant in many fish-culture ponds and all control ponds without fishes in spring, late autumn and early winter. Dominant species of copepods were Sinocalanus tenellus, Cyclops vicinus, Thermocyclops taihokuensis. The biomass of copepods in the control ponds without fishes was higher than that of the fish-culture ponds. 相似文献
11.
A NEW PROPOSAL FOR DENSITY SALINITY SCALE (DSS98) 总被引：2，自引：0，他引：2
ＩＮＴＲＯＤＵＣＴＩＯＮＳａｌｉｎｉｔｙａｎｄｉｔｓｍｅａｓｕｒｅｍｅｎｔａｒｅｂｅｉｎｇｃｏｎｔｉｎｕｏｕｓｌｙｓｔｕｄｉｅｄｂｅｃａｕｓｅｏｆｔｈｅｉｒｉｍｐｏｒｔａｎｃｅｉｎｏｃｅａｎｏｌ ｏｇｙ,ｌｉｍｎｏｌｏｇｙａｎｄｖａｒｉｏｕｓｐｒｏｄｕｃｔｉｏｎａｃｔｉｖｉｔｉｅｓ.Ｔｈｅｄｅｆｉｎｉｔｉｏｎｏｆｓａｌｉｎｉｔｙａｎｄｔｈｅｓａｌｉｎｉｔｙｍｅａｓｕｒｉｎｇｍｅｔｈｏｄｏｌｏｇｙｕｎｄｅｒｗｅｎｔｓｅｖｅｒａｌｒｅｖｉｓｉｏｎｓ(Ｚｈａｎｇ,1 986;ＣｈｅｎａｎｄＷｕ,1 980 ;Ｌｅｗｉｓ,… 相似文献
12.
Biological invasion poses a huge threat to ecological security.Spartina alterniflora was introduced into China in 1979,and its arrival corresponded with negative effects on native ecosystems.To explore geographical variation of its expansion rate in coastal China,we selected 43 S.alterniflora sites from Tianjin Coastal New Area to Beihai.The area expansion rate,expansion rate paralleling and vertical to the shoreline were analysed based on Landsat images and field survey in 2015.Simple Ocean Data Assimilation(SODA)and climate data were collected to statistically analyse the influential factors of expansion rate.Results showed that significant difference of S.alterniflora area expansion rate among different latitude zones(P<0.01),increasing from 6.08%at southern(21°N–23°N)to 19.87% in Bohai Bay(37°N–39°N)along latitude gradient.There was a significant difference in expansion rate vertical to shoreline in different latitude zones(P<0.01)with the largest occurring in Bohai Bay(256m/yr,37°N–39°N),and showed an decreasing tendency gradually from north to south.No significant difference and latitudinal clines in expansion rate paralleling to shoreline were observed.Expansion rate had significant negative correlation with mean seawater temperature,the lowest seawater temperature,current zonal velocity and meridional velocity and presented a reducing trend as these biotic factors increased;however,they were not significantly correlated with the highest seawater temperature and mean seawater salinity.We identified significant correlations between expansion rate and annual mean temperature,the lowest temperature in January and annual precipitation,but there was little correlation with annual diurnal difference in temperature and the highest temperature in July.The rapid expansion rate in high-latitude China demonstrated a higher risk of potential invasion in the north;dynamic monitoring and control management should be established as soon as possible. 相似文献
13.
According to the data of main environmental factors and the depth of localized corrosion of carbon steel and low alloy steels in China seas, combined with the result of grey interrelation analysis, double-factor method was proposed to evaluate and classify seawater corrosiveness. According to the temperature of seawater and the biologically adhesive area on steels, the corrosiveness of seawater from low to high level is classified into five levels （C l-C5）, which was identified by the data of corrosion depth of carbon steel immersed in water for one year. 相似文献
14.
研究了盐度对黄鳍鲷SparuslatusHouttuyn、平鲷Rhabdosargussarba（Forskal）、黑鲷Sparusmacrocephalus（Basilewsky）和真鲷Pagrsomusmajor（TemmincketSchlegel）4种鲷鱼精子活力的影响。对南海区4种鲷鱼精子的适盐性及其活力进行了比较,黄鳍鲷、平鲷、黑鲷和真鲷精子激活所需的最低盐度分别为8、10、＞8、＞10;激活的最适盐度则分别为21、22、25、25,与之相应的精子活动（涡动）时间分别为14．7、17．7、17．2、18．0min;在高盐条件（盐度40左右）下,黄鳍鲷精子的适应性最强,精子活力最好,其次是黑鲷、真鲷的精子,平鲷精子对高盐条件的适应性最差。 相似文献
15.
Chemical means were used to extract polyphenols from healthy brown algae collected in littoral seawater. Experiments on corrosion
of A3 steel, the time-potential curve, and polarization curve in polyphenols seawater showed stronger cathodic polarization compared
with that in common seawater. This indicates that brown algae polyphenols might feasibly be used as corrosion inhibitor in
seawater.
Contribution No. 3763 from the Institute of Oceanology, Chinese Academy of Sciences.
Project 59471054 supported by NSFC and National “Nineth Five Year” Project 96-916-04-01. 相似文献
16.
滨海平原弱透水层广布且多赋存古咸水，其盐度分布及运移过程深刻影响着含水层地下水的演变，却得到甚少关注。采集了江苏滨海区7个浅层钻孔弱透水层原状样品，压榨法收集孔隙水。利用孔隙水天然示踪剂ρ（Cl-），ρ（Br-）剖面和数值模拟分析了弱透水层孔隙水盐度特征和运移机制。得出浅层孔隙水ρ（Cl-）垂向剖面存在2个趋势:①峰值在表层，沿深度逐渐下降；②峰值在深度25m左右，向两端浓度降低。孔隙水ρ（Cl-）为486.2~38 036.7 mg/L，Cl/Br比值为72~360（均值241）。ρ（Cl-）与Cl/Br比值关系及剖面分布说明孔隙咸水为海相成因，来自于全新世海侵时期的古海水，并受到后期淡水的稀释。弱透水层孔隙水一维垂向运移数值模型表明海侵-海退事件控制了海岸带弱透水层孔隙水的盐度演变，全新世古海水仍封存在沉积物中，更新世时期的海水已被驱替。孔隙水运移以扩散为主，垂向运移速率为0.43~15.8 mm/Ma。在相对高渗透性的粉砂地层中，可能还受到侧向对流的影响。弱透水层中古海咸水的重新分布，尤其在地下水超采条件下，可能成为地下水的重要咸化来源。 相似文献
17.
Results are presented of the longitudinal and vertical profiling of salinity and suspended particulate matter (SPM) at the Muthupet estuary, India, during a one year period under widely varying freshwater flow conditions. Freshwater flow was available during post-monsoon and monsoon. An up-estuary shift in the location of estuarine turbidity maxima (ETM) was observed during the transition from post-monsoon to pre-monsoon and further it shifted downstream during the transition from pre-monsoon to monsoon, thereby exhibiting a pronounced seasonal cycle. The salinity intrusion was dependent on the freshwater discharge and was expressed as a power function of freshwater flow, explaining 97% of the variance. The formation of a salt plug in Muthupet estuary and its seasonal dynamics were observed, which is not an identified feature of any of the Indian estuaries studied so far. The geographical positions of salt plug and ETM core were more or less the same during their formation. The occurrence of two ETM during the LW of post-monsoon and the absence of ETM during monsoon explains the strong seasonal variation in the formation of ETM. The primary factor affecting the formation of ETM was identified as the freshwater flow over an annual cycle; the resuspension of sediments by tidal current affecting the formation on a flood/ebb cycle was secondary. The extent of shift of ETM was found to be an inverse logarithmic function of the freshwater discharge. The separation between ETM intrusion and salinity intrusion increased two fold with the increase in ETM intrusion. 相似文献
18.
The relation between distribution of zooplankton and salinity in the Changjiang Estuary 总被引：3，自引：0，他引：3
Seasonal netzplankton samples from stations in the Changjiang (Yangtze River) Estuary were collected from May, 2004 to February, 2005. The dominant species and their contribution to the total zooplankton abundance were determined. Moreover, the relationship between the salinity and abundance was studied with stepwise linear regression. During the whole year, the salinity was positively correlated with the abundance, while the temperature, negatively. Linear regression analysis showed also a high positive correlation with salinity for total abundance in August and November, while in February and May, no obvious relations were found. The most abundant community was composed of neritic and brackish-water species. The North Passage (NP) (salinity <5) was greatly diluted by freshwater while the North Branch (NB) was brackish water with salinity range of 12–28. Consequently, clear decline in abundance of zooplankton was along the estuarine haloclines from the maximum in the area of high salinity to the minimum in the limnetic zone. Total zooplankton abundance and biomass were lower in NP than the NB in all seasons. In short, the salinity influenced the abundance of each species of zooplankton, and ultimately determined the total abundance of zooplankton. Furthermore, a winter peak in the abundance existed, which might be caused by the flourishing of Sinocalanus sinensis, a widely distributed species in the Changjiang Estuary. 相似文献
19.
INTRODUCTIONBrownalgaepolyphenol (BAP)isadistinctivenaturalproduct,anactiveorganicmatterre leasedfromnormalgrowingbrownalgaeintoseawater.TheBAPoutputfromthelivingbrownalgaeis 1g (m2 ·d) (Craigieetal.,1 964 ) .About3 7%ofdissolvedorganicmatter(DOM)inseawateralongshoreisthesecretionfromseaweedcells,andcanreach 70 %oftotalDOMinseawaterifor ganicmatterreleasedbydeadalgaeisincluded (Raganetal.,1 979) .BAP (mainlycomprisingtheyellowmatter)inseawateralongshore ,canreach 2 .5mg L (Rashida… 相似文献
20.
Genesis of underground brine along south coast of Laizhou Bay： hydrochemical characteristics 总被引：1，自引：0，他引：1
1 INTRODUCTION Two large-scale concentration mechanisms, evaporation and freezing, have been proposed for marine origin brine production (Bein and Arad, 1992; Bottomley et al., 1999). There are three basic requirements for brine formation by seawater evap… 相似文献