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1.
Investigations on the preparation, structure and biochemical characteristics of tropomyosin (Tm) of Acetes japonicus, A. chinensis and Pseudeuphausia sinica, collected from Xiamen coastal water, show that: (1) Tm could be isolated by salting fractionation in the range of 20-35% ammonium sulphate saturation, and the contents of them are 0.86%, 0.87% and 0.70% of dry weight respectively. (2) Molecular weight of Acetes detected by SDS-PAGE method is 3.3-3.6×104, while that of P. sinica, 3.2-3.5×104. (3) Isoelectric points of all the three Tm determined by isoelectric focusing method are at about pH 5.0. (4) Crystalline spindles of above three Tm can be formed in phosphate buffer containing Mg f at pH 4.8 or pH 7.2, showing cross striations with a repeat period of 38-40 nm under the electron microscope by negative staining, and there are fine lines at irregular intervals in each striation. (5) The characteristics of the chemical composition of three Tm reveal that the strong polar amino acids account for m  相似文献   

2.
This paper uses the Kristrom (logit) spike model to analyse contingent valuation (payment card) data from a study of 2180 domestic and international visitors taking reef trips to the Northern section of the Great Barrier Reef. It investigates: (a) their willingness to pay for a “100% guaranteed sighting” of several different marine species; and (b) the sensitivity of final estimates to various methodological issues. It finds that final estimates are particularly sensitive to questionnaire design, but that the ranking of species (from most to least ‘valued’) is robust across a range of methodological specifications. The most valued groups of species were (in order): whales and dolphins; sharks and rays; ‘variety’; marine turtles; and finally large fish. Evidently, whale watching is not the only potentially lucrative source of tourism revenue; other marine species may be similarly appealing. These potential revenues need to be considered when making decisions about whether or not to conserve marine species.  相似文献   

3.
Karyotypes of three species of the marine Veneroida molluscs   总被引:1,自引:0,他引:1  
INTRODUCTIONExceptforcorbiculalivinginfreshwater,themostVeneroidamolluscsliveinthesea .Theyarewidelydistributedwithlargequantityofcategories.Manyofthebivalvemolluscsareculturedfortheireconomicvalue .ThespeciesofSolengrandis,SaxidomuspurpuratusandMactrachinensisareaquaculturedinthenorthernseasofChina .Morphologyandcultivationbiologyofthebivalvemolluschavebeenreported (Qietal.,1 989;Weietal.,1 995;Wangetal .,1 984 ) .Asthefoundationofbivalvemollusccytogenetics ,chromosomestudyiscritical…  相似文献   

4.
The paper deals with the question of Holocene transgression on the southern plain of the Changjiang Delta.At the beginning of the transgression, the paleovalleys of the Changjiang and Qiantang Rivers were covered by sea water at first.The shoreline of 8000-7500 yr BP coincided with the -7m isobath of paleotopography. Sea level had already been the present level about 7000-6500 years ago, and the Holocene transgression reached its maximum extent. During the period, the Changjiang and Qiantang Rivers and the Dongtiaoxi valley were turned into estuaries; the eastern area of Shanghai became a shallow sea; some of the bays and lagoons were distributed on the Hang-Jia-Hu and Tao-Ge Plain; the hilly region around the Taihu Lake was coastal marsh and freshwater swamp. Gangshen on the west of Shanghai was formed 7000-4000 yr BP, and during the last 4000 years, the eastern coastal plain of Shanghai advanced quickly toward the sea, and partial clear land of the western Taihu Lake was enclosed and charged into a fre  相似文献   

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6.
Quaternary marine ostracoda on the west coast of the Bohai Sea   总被引:1,自引:0,他引:1  
According to the results of analysis of the marine ostracoda biofacies from over 160 drilled holes on the west coast of the Bohai Sea, i.e. Hebei and Shandong Provinces, Tianjin, and the east part of Beijing, the present paper is a discussion of their palaeoecological and stratigraphigical significance. The investigation of ostracoda thanatocoenoces in the modern coastal zone suggests that the distribution of marine ostracoda has been controlled by the salinity and depth of water. The study of Quaternary marine ostracoda should be concentrated mainly on the determination of their biofacies and palaeogeographigical conditions, so as to provide evidence for the determination of transgression range, palaeoshoreline and sca-leve! changes.  相似文献   

7.
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   

8.
The worldwide increase in commercial fisheries and its impact on ecosystems as well as inefficient fishery management have led to overfishing and frequent breakdown of traditional fish stocks.In this context,an analysis of Khuzestan inshore fisheries data covering the years 2002–2011,was conducted in reliance on testing for occurrence of the fishing down marine food webs(FDMFW) phenomenon in the North of Persian Gulf Large Marine Ecosystem(LME).In this study,the mean trophic level(m TL) and the fishing-in-balance(FIB)-index of Khuzestan landings during this period of time were estimated using the trophic level of 47 fishery resources.Increase in total landings(Y) was observed,which explained the high fishing yield in major fishery resources(especially demersal).Moreover,the moderates decreasing trend in m TL per decade,and the increasing trend in FIB-index were observed.The status of fishery resources in Khuzestan inshore waters(under exploited but not overexploited),the rise in Y,FIB and slightly drop in m TL can be considered as indirect indicators of the fishing impacts on the trophic structure of marine communities.Based on this result,probability occurrence of FDMFW process in Khuzestan inshore waters is low to some extent.However,we suggest that the goal of management programs in Khuzestan inshore waters should prevent the continuance of this trend in the long-term using an ecosystem-based approach.  相似文献   

9.
StudyonthecharacteristicsofthemarineboundarylayerintheEquatorialPacific¥ZhangZiyuandZhouMingyu(ReceivedAugust21,1993;accepted...  相似文献   

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11.
By means of physicochemical modeling with the Selector software package, a model for the mixing of riverine water (pH = 7.02) and seawater was compiled and calculated. The Razdol’naya River-Amur Bay (Sea of Japan) system was assessed as an example. By means of the MINTEQA2/PRODEFA2 software package, the role of the sorption processes in riverine and marine waters, as well as in the zone of their mixing, was ascertained. The physicochemical migration forms of microelements (arsenic, vanadium, chromium, cobalt, and mercury) in the waters of the geochemical system considered and their behavior in passing through the geochemical barrier were established.  相似文献   

12.
Reproductive features of the poorly known oceanic squid Octopoteuthis sicula are described and quantified to gain insight into the reproductive biology of the species. The data are based on 39 complete and partial specimens from southern African waters, collected between 1975 and 2005. The specimens ranged in mantle length from 38 mm to 290 mm and included juveniles and mature females and males. The species shows female-biased sexual size dimorphism. Ovulation is asynchronous, indicating a repeated spawning strategy. Males transfer spermatophores presumably by using their long terminal organ. Spermatangia (discharged spermatophores) were found implanted in several parts of the body in both females and males, including in the anterior dorsal and ventral rugose, semi-gelatinous mantle tissue of maturing and mature females. This modified mantle tissue was only well developed in females. The morphologies of the spermatophore and the spermatangium of O. sicula are described. The spermatophoric reaction is reconstructed, using various stages of discharge, to provide insight into the process of intradermal implantation of spermatangia of this species.  相似文献   

13.
Heat oscillation in the upper ocean of the southern South China Sea   总被引:3,自引:0,他引:3  
Data used in this study are temperature/depth profiles taken over the upper 400 m of the ocean in the southern South China Sea (4°-14° N, 106°-120° E) for the period 1961-1973. The data are analyzed on the grid 2 (latitude) by 2 (longitude) in space and bimonthly in time. The vertically averaged temperature (TAV) over the upper 100 m of the ocean is calculated as the estimate of the heat content in the upper ocean.The TAV is cooler in the northwest region of the study area and warmer in the southeast in the annual and seasonal mean figures. The first EOF (Empirical Orthogonal Function) of anomalous TAV accounts for 41 % of the total variance for the period 1961-1973. The time function associated with it displays a significant interannual changes in the heat content, with 2-4 a oscillation period and associated with the ENSO events. During ENSO event TAV increases with the tendency of increasing towards equator along the basin. This anomalous states also exist in the water layers below 100 m depth. T  相似文献   

14.
15.
Understanding the temporal dynamics of seagrasses and the major influences on seagrass growth is critical for seagrass habitat conservation and administration. However, little work has been done regarding these issues in southern China. To examine inter-annual and seasonal variations of the intertidal Halophila ovalis community in southern China, we conducted quarterly sampling using the SeagrassNet methodology and assessed environmental conditions as well as direct anthropogenic impacts on the seagrass meadow from July 2008 to October 2014. Our study demonstrated strong inter-annual and seasonal dynamics of the intertidal seagrass meadow in the study area. Generally, the community performed best (highest seagrass cover, leaf area, shoot density, total biomass) in summer and worst in spring among the 4 seasons. The temporal variations in the seagrass community attributes (e.g. above-ground biomass) were significantly affected by precipitation, atmospheric visibility, and salinity, while leaf width was significantly negatively correlated with temperature, atmospheric visibility and salinity. Temperature was a major factor influencing the seagrass community (both macroalgae and seagrass), with temperature data showing an inverse relationship between seagrass and macroalgae. The above-ground: below-ground biomass ratio and leaf width of H. ovalis were the most sensitive plant parameters monitored when assessing environmental interactions. Human physical disturbances did not have a significant effect on seagrass dynamics in the study area. We concluded that long-term monitoring (like SeagrassNet) is valuable in understanding the relationship between environmental variables and seagrasses.  相似文献   

16.
The analysis of 103 samples collected quantitatively from the southern Taiwan Strait (22°4'-24°3'N, 117°5'-119°9'E), China, in August 1997 indicates that the abundance of heterotrophic nanoflagellates (HNF) ranges from 391 to 1 846 ×103 cell/dm3, with an average of 949 × 103 cell/dm3, and 96.2% of cells are in size of 2-22 μm in all HNF met in the samples. The HNF cells are 9.83-45.79 μg/dm3 after conversion from cell number to carbon content, with an average of 22.82 μg/dm3 . The HNF abundance is relatively low in comparison with other areas. The nitrogen and phosphorus nutrients of the water are lower than previous investigations, which may be caused by the El Nino. The biomass of HNF is higher in southern waters, where cell concentration is 3-5 folds higher than that in other waters, and nearly 2-fold as high as the average of the investigated areas. The HNF is mainly habitat in 0-30 m water layer. Both horizontal and vertical HNF distribution must be influenced by hy-drographical dynamic pro  相似文献   

17.
In this paper the authors cite the aerosol samples collected with a KA-200 Anderson cascade Impactor and a KB-120 sampler during the first cruise of the Kuroshio investigation operated by the People's Republic of China and Japan cooperative program, from July 23 to August 21, 1987. The concentration size distributions and composition of marine aerosols over the Kuroshio area are analyzed. Neutron activation analysis is used to determine the elemental composition of the aerosols. The authors also discuss some characteristics of marine aerosols relating to long-range transport of crustal and anthropogenic elements from the continent to the remote ocean. Analytical results indicate that elements Al, Fe, Sc and Sb over this area are obviously influenced by the continent of Asia, and the size distributions are changed after long-range transport. The concentration of large particles increase. The concentrations of the elements C1 and Na are closely related to ocean conditions; the source of the elements Cl an  相似文献   

18.
This paper is a comparative analysis of the contribution to UK marine governance of two recent EU initiatives: the Marine Strategy Framework Directive (MSFD) and Marine Spatial Planning (MSP). MSFD imposed a duty on Member States to achieve Good Environmental Status (GES) in four regional seas, while MSP required Member States to replace their fragmented, sector-based system of maritime decision making with an integrated approach. This paper explains MSFD and MSP, examines their relationship, and compares their practicability, concluding that MSP is both the more dominant and the more practicable instrument, reflecting the UK's preference for sustainable development over conservationism in marine policy. A recent proposal by the European Commission to make MSP and integrated coastal management a Directive reinforces the UK position.  相似文献   

19.
Almost 1 000 South African fur seals Arctocephalus pusillus pusillus were collected at sea (inshore and offshore) for examination of stomach contents and other biological parameters. The main prey of seals above the age of one year was teleost fish, of which at least 28 species were identified. Overall, 74,6 per cent of the diet was teleost fish, 16,7 per cent cephalopods, 4,8 per cent crustaceans such as shrimps, prawns, amphipods and isopods and 3,2 percent rock lobster. Within this overall dietary pattern there were marked regional differences. The importance of individual fish species in the diet was investigated from the numbers and the sizes of otoliths occurring in the stomachs, from which the identity and size classes of the prey species could be calculated. Again there were regional differences in the importance of different prey species. On the west coast of South Africa the most important species were anchovy and Cape hakes (each 23% of total diet), whereas on the south coast the important species were anchovy (17%), horse mackerel (14%), pilchard (12%) and Cape hake (14%). Off South West Africa the two dominant species were pelagic goby (52%) and horse mackerel (23%), anchovy and Cape hake constituting only 4 and 5 per cent respectively of total diet. The total annual consumption of anchovy and Cape hake by seals in South African waters was calculated at 125 000 and 120 000 tons respectively.  相似文献   

20.
Numerical simulation on diurnal and semidiurnal tidal currents is made for the eastern and southern parts of the East China Sea bounded by the Tsushima, islands of Kyushu and Ryukyu in the east and extending to the central Taiwan Strait in the south. The numerical computation shows that the rapid variation in the seabed topography near the Okinawa Trough may cause computational instability and this instability can be removed by setting a suitable lateral eddy viscosity. The computed results are in good agreement with the observations and indicate that the tidal currents in the greater part of the area studied rotate clockwise. An M2 current-amphidromic point exists in the southern part of the Korea Strait and another one appears in the west of Okinawa with less certainty. K1 and M2 cotidal charts based on the observed and computed tidal currents in the sea and the observed tides on the coast are also given.  相似文献   

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