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1.
Dissolved iodine species and the relationship between its distribution and salinity in Jiulong River estuarine water have been determined. It has been found that the total iodine, iodate and iodide are positive linear with salinity. This indicates that dissolved iodine species (IO-3 and I- ) in estuarine water .how conservative behaviour. The river water contains 2. 40μg/1 as iodide and less than 1. 0μg/1 as iodate, and iodide is the predominant species. Whereas the sea water contains 39. 4μg/1 as iodate and 4. 00μg/1 as iodide, and iodate is the dominant form. The distribution of dissolved iodine in pore water, as a function of depth, has been studied. Iodine in pore water occurs as iodide. The apparent fluxes of soluble iodine from the sediment to the overlying water in the estuary have been determined. The values are 2. 4 (15℃) and 27μmol/(m2·d) (30℃) respectively.  相似文献   

2.
The behaviour of free methionine in the artificial marine habitat and the characteristic of absorption by clam were studied by trace method. The results showed that more than 70% of free methionine was utilized by marine organisms. The percentage of concentration methionine in suspended matter, Platymonas, sediment and clam was 11.4%, 24%, 7.8% and 34% respectively. The main path of absorption was viscera, seconded by mantle and gill. It was transferred to muscle after 24 h. The direct absorption of methionine from sea water by clam was more important and faster than that from food.  相似文献   

3.
I.M.L. Ridge 《Ocean Engineering》2009,36(9-10):650-660
An earlier paper by the author discussed the behaviour of helically spun wire ropes when subject to axial load [Ridge, I.M.L., 2008. Torsional characterization of ropes used offshore. Journal of Strain Analysis 43(2), 121–139.]. The response of the rope varied, depending upon the rope's construction and whether the end of the rope was free to rotate or was fixed. This paper presents the results of an extensive research programme which highlight the practical implications of the torsional fatigue behaviour of ropes with especial reference to their use in offshore applications. The results are also relevant to a much broader range of rope applications where long lengths of rope are employed such as deep mine hoisting and reversible aerial cableways. The torque which may be generated in the various components used offshore may have serious effects in both handling and installation, as well as in the longer term service (fatigue) performance.  相似文献   

4.
Under the artificial condition the 59Fe morphology in sea water, its concentration in sediment and phytoplankton, its distribution and metabolism in tissue organs of marine animals were studied. The results showed that the morphology of 59Fe was in a particulate state in sea water. The adsorption rule of 59Fe by three kinds of sediments was similar. The concentration ability of 59Fe by phytoplankton was very strong. The critical concentration organs of S9Fe by marine animals were viscera. The gross radioactivity of 59Fe was mainly concentrated in protein. The concentration factor of 59Fe by DNA was the highest one. After excretion experiment, 59Fe of all the tissue organs was not detected. Small part of59Fe remained in the organic acid and protein state. There was a redistribution process in sediment for59Fe.  相似文献   

5.
Abstract

Mono-pile foundations have been widely used for offshore wind turbines principally due to their convenient construction and cost-effective nature. So far, little attention has been paid to large diameter “semi-rigid” piles that have distinct behaviours from flexible or ideally rigid piles. This paper presents a series of centrifuge model tests to study the deforming and bearing characteristics of a 5.9 dia. semi-rigid pile under lateral loadings in kaolin clay. For monotonic loading, a modified p–y curve analysis model considering rotational soil flow near the rotation centre of pile was proposed, highlighting the limitation of classic plane-strain based plasticity models to evaluate the ultimate lateral pile-soil resistance. For cyclic loading, a strong correlation between the degree of soil degradation and cyclic load amplitude was identified. Besides, a degradation factor model, accounting for various cyclic stress levels and soil depths, was proposed, which can be used to assess the accumulative displacement of semi-rigid piles under cyclic loadings in soft clay.  相似文献   

6.
European eel (Anguilla anguilla) recruitment is declining dramatically since the 1980s. Causes for this decline are explained by a combination of environmental changes basically affecting oceanic larval stages and a variety of anthropogenic impacts during the continental phase. Today, evidence is growing that poor silver eel quality has a major impact on reproductive success, implying that habitat quality plays a key role in stock decline. Since eels are frequently moving through a variety of different habitats during their life cycle, a better understanding of the implications of individual diadromous behaviour and habitat choice on spawner quality are crucial for management considerations for a stock recovery. The present study tested whether individual migratory behaviour and habitat choice of European eels affect spawner quality. Therefore, the migratory behaviour of 287 European eels from marine, brackish and freshwater stations in the North Sea, the Baltic Sea and from Northern German inland waters was examined by otolith strontium/calcium analysis. All individuals were classified either as freshwater residents, coastal residents, downstream shifters, upstream shifters or interhabitat shifters. As indicators for eel quality, muscle fat content, infection with the introduced swimbladder nematode Anguillicoloides crassus and body length at onset of spawning migration were assessed. Results indicate that individuals that exclusively inhabited freshwaters had significantly lower muscle fat contents and were more seriously infected with A. crassus than eels that never entered freshwaters. Since high fat contents are considered as prerequisites for a successful transoceanic spawning migration and high A. crassus loads have a negative impact on condition, this study outlines the importance of brackish waters as eel habitats in temperate latitudes. Furthermore, it questions the net benefit of stocking programs for the European eel population, since they include the translocation of eels from coastal waters into freshwaters.  相似文献   

7.
Managers of marine protected areas (MPAs) are constantly challenged to encourage positive user behaviour to minimise impacts on marine ecosystems while allowing recreational use. Yet, some marine users continue to act in ways that diminish conservation values of the area. Drawing on social psychological theories, this paper presents a case for informed behaviour change strategies to reduce problem behaviours in MPAs and contribute to conservation efforts. Social psychological drivers of behaviour are explained and applied to an MPA context to demonstrate how they can inform strategies for predicting and changing behaviour using persuasive communication. As behavioural and persuasive communication theories are seldom invoked and almost never rigorously applied to MPAs, the review offers new theoretical and practical insights into how they can assist MPA management to target and shift specific behaviours that ultimately support marine park values.  相似文献   

8.
-This paper first presents a new potassium reagent and efficient enrichment agent for direct recovery of potassium from seawater, i. e. , 1, 2, 4, 5-tetrahydroxybenzen -O, O' , O", O''- tetraacetic acid (TTAH4). The synthetic method of TTAH4, its enrichment behaviour for potassium ion in low concentration solution and seawater, and the chemical structure of its corresponding potassium salt have been investigated. A mechanism which caused the uptake of potassium ion is suggested. Elementary analysis and IR-spectrum determination of the potassium salt proved correct evidence for a polynuclear complex, i. e. , (TTAH3K)n. Thus, the mechanism which caused the uptake of potassium ion may be interpreted in terms of the formation of polynuclear chains as a continual sandwich type coordination complex.  相似文献   

9.
This paper first presents a new potassium reagent and efficient enrichment agent for direct recovery of potassium from seawater,i.e.,1,2,4,5-tetrahydroxybenzen -O,O'',O",O''"-tetraacetic acid (TTAH4).The synthetic method of TTAH4,its enrichment behaviour for potassium ion in low concentration solution and seawater,and the chemical structure of its corresponding potassium salt have been investigated.A mechanism which caused the uptake of potassium ion is suggested.Elementary analysis and IR-spectrum determination of the potassium salt proved correct evidence for a polynuclear complex,i.e., (TTAH3K)n.Thus,the mechanism which caused the uptake of potassium ion may be interpreted in terms of the formation of polynuclear chains as a continual sandwich type coordination complex.  相似文献   

10.
Several studies have shown that eel diadromy is facultative and that migratory divergences may appear during glass eel estuarine migration. The origin of the differences in migratory behaviour among glass eels remains unclear but initial evidence supports the role of individual energetic and thyroidal status. Even if starvation is usually associated with glass eel migration, feeding does seem to occur in some glass eels. The aim of the present study was to investigate feeding behaviour and glass eel growth in relation to the propensity to migrate. Feeding rate and weight gain were higher in fish having a high propensity to migrate (M+ fish) than in fish having a low propensity to migrate (M fish) in fed glass eels, whereas no clear difference in the variation in body weight was observed among unfed fish (controls). M fish initially had lower percent dry weight than M+ fish, which suggests a link between appetite, propensity to migrate, and energy content. We discuss the role played by endocrine signals on these processes. In fish, thyroid hormones contribute to the control of growth and development. In addition, they play a role in flatfish and leptocephalus metamorphosis and appear to be involved in smolt and glass eel migratory behaviour. As such, they represent a good candidate which would promote the propensity to migrate as well as digestive system development. Their role in the hormonal control of food intake however remains vague.  相似文献   

11.
12.
This paper first presents the molecule design and synthesis of crown-link type alkyd resin,and its enrichment behaviour for potassium ion in low concentration solution and sea water.On the basis of some theory concepts of Host-Guest chemistry developed in recent years,we have designed and synthesized a new polymer enrichment agent of crow-link resin for potassiumion,i.e.,polymacrocyclic ether bislactone of diethylene glycolpyromyllitic acid(briefly called crown-link type alkyd resin or PBL resin).The yield was about 97.4%,almost quantitatively.  相似文献   

13.
African penguins Spheniscus demersus closely resemble Magellanic S. magellanicus and Humboldt S. humboldti penguins and have similar breeding and feeding ecologies. Adults feed on pelagic schooling fish in continental shelf waters, but African penguins have been reported to have shallower dive angles and remain submerged longer for dives to a given depth than their congeners. The few data for African penguins were gathered using relatively large time-depth recorders. We measured diving behaviour of 36 African penguins provisioning small chicks at three colonies near Cape Town, South Africa. Maximum and mean dive depths were 69m and 14m respectively. Diving took place mainly during the day. Although dive depths differed between colonies, there were no significant differences in dive duration or maximum, median or mean depth. Total dive duration, descent time, bottom time, ascent time and dive angle all were strongly correlated with the maximum depth attained. The diving behaviour of African penguins is similar to that of its congeners. Diving performance probably was compromised by the data-logger used in the previous study. Comparative data from Humboldt penguins also indicate potential biases in an earlier study of this species. Care is needed when comparing the diving performance of penguins measured using different loggers.  相似文献   

14.
Chemistryofmarineresources-XIX.Themoleculedesignandsynthesisofcrow-linktypealkydresinanditsenrichmentbehaviourforpotassiumion...  相似文献   

15.
This review outlines the most significant results of research in dynamic meteorology performed by Russian scientists in 2011–2014. It is part of the Russian National Report on Meteorology and Atmospheric Sciences submitted to the International Association of Meteorology and Atmospheric Sciences (IAMAS). The report was considered and approved at the 26th General Assembly of the International Union of Geodesy and Geophysics (IUGG).1 The review is followed by a list of key publications on dynamic meteorology of Russian scientists in 2011–2014.  相似文献   

16.
17.
Many macrofaunal species inhabiting exposed sandy beaches are dependent on the swash for their nutrition and migration and are highly adapted to the harsh physical conditions of the swash. The most important physical factors that determine the distribution and behaviour of swash related fauna, next to the swash itself, are sediment grain size and beach slope. Crucial swash parameters are swash period and swash velocity. Studying the influence of these factors on the animals in the field is often very difficult and it is almost impossible to identify which factor causes what effect. Crucial knowledge about the direct role of the swash itself is lacking. Therefore, a device that generates swash waves on an artificial beach under laboratory conditions was designed: the swash rig. In the swash rig, full and independent control on sediment grain size, beach slope, swash velocity and swash period is present. This will allow us to do a variety of experiments on the influence of each of these factors, independently or combined, on swash fauna. In one such experiment, Olivella semistriata – a dominant surfing gastropod on Ecuadorian sandy beaches – was placed in the swash rig during rising and falling tide and subjected – under constant conditions – to an equal wave regime. During falling tide, and in absence of any tidal cue, almost all specimens moved downshore, as they would in the field; hardly any specimens moved upshore. During upcoming tide, however, there was noticeable upward migration in the swash rig, and half of the runs showed a net upward migration. Contrary to the common understanding that the behaviour of sandy beach molluscs is entirely environmentally driven, this experiment hints at the presence of an endogenous circatidal clock, which is used to direct the tidal migration of the species.  相似文献   

18.
A brief review of the results of investigations carried out by Russian scientists in the field of dynamic meteorology in 2007–2010 is presented. This review is based on the information prepared by the Commission on the Dynamic Meteorology of the National Geophysical Committee, Russian Academy of Sciences, and included in the general information report of the Section of Meteorology and Atmospheric Sciences at the XXV General Assembly of the International Union of Geodesy and Geophysics.  相似文献   

19.
A brief review of the studies performed by Russian scientists in dynamic meteorology in 2003–2006 is presented. This review is based on the material prepared by the Commission on Dynamic Meteorology of the National Geophysical Committee of the Russian Academy of Sciences and included in the general information report of the Section of Meteorology and Atmospheric Sciences at the 24th General Assembly of the International Union of Geodesy and Geophysics.  相似文献   

20.
Golubeva  N. I.  Burtseva  L. V.  Gromov  S. A. 《Oceanology》2018,58(6):870-878
Oceanology - The article presents the results of measurements of Pb, Cd, Cu, Zn, Ni, Co Cr, As, and Fe concentrations in atmospheric aerosols in the surface layer over the Kara Sea. The data were...  相似文献   

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