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1.
The palynolpgical study on the Quaternary sediments of 42 cores in the region of the Yangtze River Delta and the sections of 4 relics had been done since 1960. Palynological assemblages from the region of the Yangtze River Delta, showing obviously .common characteristics but with slight differences because of the vast areas covered, can be divided into five spores and pollen zones and three subzones in ascendant order:I.Quercus alienc-Pinus-Cupressaceae-Chenopodiaceae spores and pollen zone reflecting the cool, then cold and dry climate--Preboreal.II.Quercus dentata-Quefcus acutissima-Pinus-Castanea-Artemisia spores and pollen zone reflecting the temperate and cool, but a little dry climate--Boreal.III.Quercus glauca-Caslanopsis-Myrica-Caslanea spores and pollen zone reflecting the hot and moist climate--Atlantic.IV.Quercus acutissima-Pinus-Castanea-Quercus glauca- Chenopodiaceae spores and pollen zone reflecting the warm, and a little dry climate--Subboreal.V.Quercus acutissima-Costarica-Quercus glauca  相似文献   

2.
Low frequency (LF) current (period>25 hour) variation at 5 stations in Jiaozhou Bay. Shijiousuo, and the central part of the Yellow Sea were studied by analyzing the observed long-period current data series in the study area.1) There are obvious periods of 3 and 5 days in the LF current spectra. The energy spectral value of LF current of a 5 day period is remarkably larger than that of a 3 day period. These periods reflect the correlations between the LF current variation and the LF water level variation.2) The feet that the 15-day period in the LF current spectra corresponds to the semi-monthly celestial tide period indicates that the tide-induced residual current is an important and most evident LF current component in the bay.3) The LF current spectral energy density in the northward direction is much larger than that in the eastward direction. This shows the frequency and strength of the wind field in the northward direction are evidently larger than that in the eastward direction.  相似文献   

3.
Study of the distribution and migration of the common squid,Todarodes pacificus Steenstrup,basedon the index of important fishing ground(P) and fisheries statistics on the Yellow Sea and northern EastChina Sea during 1980—1991 showed that:1.Its catch in the fishing period(June to November) is 91.77% of the annual yield.The fishingground distributes over the northem and middle Yel1ow Sea and adjacent area of the Changjiang Estuary.2. It over-winters in the northem East China Sea and waters adjacent to Goto Island from De-cember to February and spawns in waters near Haijiao Is1and and west of Kyushu. The main stock mi-grates along 123°30′E to the ChangJiang Estuary, Haizhou Bay. offsea from Shidao to Qingdao,mideastern Yellow Sea, and offsea Weihai and Haiyang Island succesively for feeding after April. The sur-plus stock migrates again to the wintering ground in December.3.The favorable feeding temperature is 6-23℃(optimum of l3-20℃ in the Changjiang Estua-ry and 7-13℃ in the northern and middle Yel  相似文献   

4.
Introduction In the Alakananda Basin, undulating terrain constitutes the most fragile elements of the ecosystem. Traditional economy rests on the terraced cultivation with extremely limited viability to expansion and modernization. Consequently, low economic return remains the characteristic feature of the agrarian landscape. It is the common experience that the ecological conditions of the basin are more suited to fruit cultivation rather than cereal farming (Atkinson 1889). Along with frui…  相似文献   

5.
It is known that the organic matter in the upper layer of sediments gets lost fast, but not in the South Huanghai Sea (Yellow sea). Some of the major characteristics of organic geochemistry of sediments in the South Huanghai Sea can be summarized as follows:1. The contents of organic carbon and bitumen increase with the decrease in grain size.2.Loss of organic matter is closely related to grain size but less so in clay sediments.3.The contents of bitumen and hydrocarbon are low, about n ×102 ppm for bitumen and n ×10 ppm for hydrocarbon.A scattered show of organic matter does not necessarily indicate the presence of petroleum in recent marine sediments.In research into the genesis of petroleum, people pay more attention to the study of the organic geochemistry of recent marine sediments. How much organic materials was lost during the deposition up to the diagenesis ? The problem is as important as the study on the transformation of organic matter. This study on the organic geochemistry of the sediment  相似文献   

6.
The deep and bottom water within the Huanghai Cold Water Mass (HCWM) in summer was, for a long time, considered as a homogeneous body of water. Various investigations in recent years showed this may not be true.After a detailed analysis of the most recently obtained refined CTD data and other historical hydrographic data at our disposal, some significant results have been obtained.1.It is definitely shown that the Huanghai Warm Current (HWC) did not enter the HCWM in summer. However, there exist two types of second class water masses within the HCWM in summer. They are: (1) a water mass with low temperature and low salinity, which was formed in the preceding winter by a vertical mixing process locally, and (2) a water mass of relatively high temperature and high salinity, which is the remanent body of the HWC that entered the HCWM in preceding seasons, but was completely cut off from its source in summer. The spreading of these two water masses, the existence of a frontal zone at the boundary of the two  相似文献   

7.
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8.
Trace and RE element geochemistry and genesis have been studied with respect to ferromanganese nodules from the sediments of the Pacific, Atlantic and Indian oceans.  相似文献   

9.
  1. The nonanthropogenic SO4 in the Changjiang River stems from weathering and oxidation of sulphate and sulphite minerals, while the anthropogenic SO4 here is attributed to acid rain containing H2SO4 formed by atmospheric sulphur oxides derived from the burning of fossil fuels in the region of the lower reaches. Ca and Mg are probably derived from weathering of carbonate minerals, but possibly less from weathering of silicate minerals.
  2. The Changjiang River estuary is characterized by two—layer flow based on the salinity section of the estuary, so a model of two—layer exchange of water—body in the Changjiang River estuary can be advanced.
  3. The presence of SO4 and K at stations H14 and H15 were found most likely to be due to the addition and removal processes, that of the other major consituents may be mainly controlled by physical mixing in this estuary.
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10.
INTRODUCTIONManystudiesonvascularplantSduringthenontwperiodhavedrireP0redinChinaandabroad.TherearefeWreportSonwhethertherearesomevasctilarplantS,andhowmanyspedessurvive,underice,andontheirbiomassesandphotosyntheticproduCtivitiesduringwinter,espedal1yduringbeAfpinchLillyamepe0ylenctal.,l976,Liuetal.,l994).WeimtlycarriedoutaseadriontheunderforvascularplantsdurinwinderinsomewaterbodieswherevascularplantSgrowluxdrianhydurinInildareonsinnorthemareas,soastoimproveourknowedgeofvascularplaflt…  相似文献   

11.
Shijiu Harbour is to be constructed at southern Shandong as an important shipping center with a docking capacity of 100 thousand tonnages of a single vessel.Tides and tidal currents were frequently observed at three different layers from December 1979 to April 1980. Bed-load discharge was sampled and calculated for different weather conditions. Some of the results are as follows:1. The amount of bed-load discharge is 0.1359 g/cm2/day during the spring tide, 0.09 g/cm2/day during the neap tide, 0.488 g/cm2/day during storm weather, which is four times as high as that during average tides.2. The maximum amount of the sediments that settle to the waterway is less than 46.7768 g/cm2 per year, therefore the waterway will not be blocked by the transported sand and clay even after a storm weather.  相似文献   

12.
On the deep sea demersal fish communities of the East China Sea   总被引：1，自引：0，他引：1  
Cluster analysis of data on the species similarity index offish samples taken at various sampling stations of different depths by the R /V " Dongfang " of the East China Sea Fisheries Research Institute, Chinese Academy of Fisheries Science, during the deep sea demersal fish resources survey in May - November, 1981, showed deep sea demersal fish fauna of the western part of the East China Sea can be grouped into the following communities :1)The outer continental shelf community ,2)The continental slope community, and3)The western Okinawa Trough community .The authors found that not only the species diversity index, but also the species similarity index are important criteria to reflect the structure of biotic community.  相似文献   

13.
Cadmium flux through a lab food chain (Phaeodactylum tricornutum Bohlin- Penaeus orientate Kishinouye- Hexagrammos otakii Jordan et Starks) and its genotoxicity were investigated. The results are as follows:1. High doses of cadmium (>0.003 mol / L) induced flocculation and quick precipitation of Phaeodactylum tricornutum; lower doses of cadmium could be adsorbed on and absorbed by P. tricornutum without delaying its growth. Cadmium concentrations in algae increased with dosage, and cadmium ions removed from the medium were in proportion to dosage. In vivo chelation and organizable combination of absorbed cadmium ions by metabolites of P. tricornutum can be considered as bio-detoxification.2. Cadmium concentration decreased in the transfers from P. tricornutum to P. orientalis and from the latter to H. otakii. Transfer coefficient of cadmium in the first flux was 66.6% and 29.9% in the second. Results of t tests showed that mutagenicity of ashed internal organs of experimental prawns was significantly hi  相似文献   

14.
As an important marginal sea under the influences of both the Changjiang River and the Kuroshio, the East China Sea (ECS) environment is sensitive to both continental and oceanic forcing. Paleoenvironmental records are essential for understanding the long-term environmental evolution of the ECS and adjacent areas. However, paleo-temperature records from the ECS shelf are currently very limited. In this study, the U 37 K′ and TEX86 paleothermometers were used to reconstruct surface and subsurface temperature changes of the mud area southwest of the Cheju Island (Site F10B) in the ECS during the Holocene. The results indicate that temperature changes of F10B during the early Holocene (11.6–6.2 kyr) are associated with global climate change. During the period of 6.2–2.5 kyr, the similar variability trends of smoothing average of ΔT (the difference between surface and subsurface temperature) of Site F10B and the strength of the Kuroshio suggest that the Kuroshio influence on the site started around 6.2 kyr when the Kuroshio entered the Yellow Sea and continued to 2.5 kyr. During the late Holocene (2.5–1.45 kyr), apparent decreases of U 37 K′ sea surface temperature (SST) and ΔT imply that the direct influence of the Kuroshio was reduced while cold eddy induced by the Kuroshio gradually controlled hydrological conditions of this region around 2.5 kyr.  相似文献   

15.
In order to obtain novel secondary metabolites, a deep sea inhabiting fungus Aspergillus versicolor CXCTD-06-6a was investigated. One new diketopiperazine brevianamide W(1a), as well as five known diketopiperazine alkaloids, diketopiperazine V(1b), brevianamide Q(2), brevianamide R(3), brevianamide K(4), and brevianamide E(5), were isolated from the Et OAc extract of the fermentation broth. Their structures were elucidated by spectroscopy techniques(NMR, MS). The six compounds exhibited moderate radical scavenging activity against DPPH with clearance ratio of 55.0%(1a and 1b), 53.7%(2), 46.2%(3), 61.4%(4) and 19.3%(5) at a concentration of 13.9 μmol L-1, respectively; while the positive control ascorbic acid showed a ratio of 70.3% at the concentration of 28.4 μmol L-1.  相似文献   

16.
A chemical investigation of the ethyl acetate extract of the fermentation broth of Alternaria tenuissima EN-192,an endophytic fungus obtained from the stems of the marine mangrove plant Rhizophora stylosa,resulted in the isolation of nine known secondary metabolites,including four indole-diterpenoids:penijanthine A(1),paspaline(2),paspalinine(3),and penitrem A(4);three tricycloalternarene derivatives:tricycloalternarene 3a(5),tricycloalternarene 1b(6),and tricycloalternarene 2b(7);and two alternariol congeners:djalonensone(8) and alternariol(9).The chemical structures of these metabolites were characterized through a combination of detailed spectroscopic analyses and their comparison with reports from the literature.The inhibitory activities of each isolated compound against four bacteria were evaluated and compounds 5 and 8 displayed moderate activity against the aquaculture pathogenic bacterium Vibrio anguillarum,with inhibition zone diameters of 8 and 9 mm,respectively,at 100 μg/disk.To the best of our knowledge,this is the first report on the secondary metabolites of mangrove-derived Alternaria tenuissima and also the first report of the isolation of indole-diterpenoids from fungal genus Alternaria.  相似文献   

17.
The spatial distribution of siliceous microfossils (diatoms and silicoflagellates) in the surface sediments was mapped at 113 sites in the Yellow Sea and sea areas adjacent to the Changjiang (Yangtze) River, China. In total, 267 diatom taxa and two silicoflagellate species were identified from the sediments. The spatial variations in abundance and diversity were classified into three distinct geographic patterns using Q mode clustering: a south-north geographic pattern, a coastal-offshore pattern and a unique pattern in the Changjiang River mouth. The south-north geographic pattern was related to the spatial variations in sea temperature. Coscinodiscus oculatus, a warm-water species, indicated these variations by a gradual decrease in abundance from the south to the north. The coastal-offshore pattern was in response to the spatial variations in salinity. Cyclotella stylorum, Actinocyclus ehrenbergii and Dictyocha messanensis, the dominant brackish species in coastal waters, significantly decreased at the isobaths of approximately 30 m, where the salinity was higher than 31. Paralia sulcata and Podosira stelliger indicated the impact of the Yellow Sea Warm Current in the central Yellow Sea. The unique pattern in the Changjiang River mouth showed the highest species diversity but lower abundance, apparently because: freshwater input can significantly increase the proportion of brackish species; nutrients can supply the growth of phytoplankton; and high sedimentation rates can dilute the microfossil abundance in the sediments. Our results show that an integration of environmental factors (e.g., nutrient levels, sedimentation rate, sea temperature, salinity and water depth) determined the spatial characteristics of the siliceous microfossils in the surface sediments.  相似文献   

18.
Bioassay-guided fractionation of the crude extract from Penicillium commune SD-118, a fungus obtained from a deep-sea sediment sample, resulted in the isolation of a known antibacterial compound, xanthocillin X (1), and 14 other known compounds comprising three steroids (2-4), two ceramides (5 and 6), six aromatic compounds (7-12), and three alkaloids (13-15). Xanthocillin X (1) was isolated for the first time from a marine fungus. In the bioassay, xanthocillin X (1) displayed remarkable antimicrobial activity against Staphylococcus aureus and Escherichia coli, and significant cytotoxicity against MCF-7, HepG2, H460, Hela, Du145, and MDA-MB-231 cell lines. Meleagrin (15) exhibited cytotoxicity against HepG2, Hela, Du145, and MDA-MB-231 cell lines. This is the first report of the cytotoxicity of xanthocillin X (1).  相似文献   

19.
Using net enclosures in an earthen pond, we established three culture treatments with the sea cucumber Apostichopus japonicus and the Chinese white shrimp Fenneropenaeus chinensis: monoculture of sea cucumbers (C), monoculture of shrimp (S), and co-culture of the two species (CS). We measured levels of suspended particulate matter in the water column; total organic matter, total organic carbon, total nitrogen, and carbon/nitrogen ratios in both settling particles and the sediment; and chlorophyll a levels in the sediment. We then compared these variables between the three treatments. We also examined growth, survival, and yield of the two species in the different treatments. From June to September, the mean monthly suspended particulate matter sedimentation rates in the CS and S treatments were significantly (P<0.05) greater than those in the C treatment. From August to November, the mean monthly total organic matter, total organic carbon, total nitrogen, and chlorophyll a contents in the sediment in the CS and S treatments were significantly ( P <0.05) greater than those in the C treatment. Final wet weight, specific growth rate, survival rate, and total yield of sea cucumbers in co-culture were all significantly greater than those of sea cucumbers in monoculture. There were no significant differences among any of these variables for shrimp reared in the two systems. The bioturbation of the sediment and fecal production of the shrimp likely supplied natural food for the sea cucumbers. Co-culture of the two species is a viable option for increasing yield per unit area, maximizing use of the water body, and diversifying crop production.  相似文献   

20.
Although the mid-late Holocene cold and dry event about 4000 years ago(the 4 ka event) has been observed almost globally, it was most prominent in terrestrial climate proxies from the lower latitudes. Here we evaluate the oceanic response to this event in terms of a Holocene sea surface temperature(SST) record reconstructed using the K'37U index for Core B3 on the continental shelf of the East China Sea. The record reveals a large temperature drop of about 5℃ from the mid-Holocene(24.7℃ at 5.6 ka) to the 4 ka event(19.2℃ at 3.8 ka). This mid-late Holocene cooling period in Core B3 correlated with(i) decreases in the East Asia summer monsoon intensity and(ii) the transition period with increased El Nino/Southern Oscillation activities in the Equatorial Pacific. Our SST record provides oceanic evidence for a more global nature of the mid-late Holocene climate change, which was most likely caused by a southward migration of the Intertropical Converge Zone in response to the decreasing summer solar insolation in the Northern Hemisphere. However, the large SST drop around Core B3 indicates that the mid-late Holocene cooling was regionally amplified by the initiation/strengthening of eddy circulation/cold front which caused upwelling and resulted in additional SST decrease. Upwelling during the mid-late Holocene also enhanced with surface productivity in the East China Sea as reflected by higher alkenone content around Core B3.  相似文献   

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