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1.
Silicon limitation on primary production and its destiny in Jiaozhou Bay, China V： Silicon deficit process 总被引：1，自引：0，他引：1
Silicon is a necessary nutrient for diatoms, silicon uptake in diatom reproduction decreased seawater silicon content. This paper clarified the characteristics of silicon transferring in the sea, which plays an important role in phytoplankton growth, zooplankton graze and marine ecosystem. Analysis revealed that silicate is supplied by terrestrial sources, through plankton uptake, death, and eventually deposits to the sea bottom, and cannot diffuse upward. This is a general silicon deficit process. Many global marine waters showed the same silicon transfer route: land→silicon biogeochemical process→sea bottom. River flow brings abundant silicate into marine waters, silicate concentration in the waters decreased in the distance away from the river estuaries. In discussion of silicon characteristics and its transfer route, it was considered that the main factor controlling the mechanism of diatom and non-diatom red tides occurrence is silicon, and the changes in silicon source. Human activities, such as sea-route cutting by building embankment and dam, and silicon supplement by the sea, such as sandstorm, rainstorm and storm tide, have largely impaired the earth ecosystem and hugely threatened the human existence. It is suggested in this paper that man should resume the original face of the Si input into the sea to keep natural ecosystem in sustainable pattern. 相似文献
2.
In this paper, the spreading way in the southern hemisphere that anomalous warm water piled in tropical eastern Pacific is analysed and then impact of E1 Nino on the variability of the Antarctic sea ice extent is investigated by using a dataset from 1970 to 2002. The analysis result show that in E1 Nino event the anomalous warm water piled in tropical eastern Pacific is poleward propagation yet the westward propagation along southern equator current hash “t been discovered . The poleward propagation time of the anomalous warm water is about 1 year or so. E1 Nino event has a close relationship with the sea ice extent in the Amundsen sea , Bellingshausen sea and Antarctic peninsula . After E1 Nino appears , there is a lag of two years that the sea ice in the Amundsen sea , Bellingshausea sea, especially in the Antarctic peninsula decreases obviously. The processes that E1 Nino has influence with Antarctic sea ice extent is the warm water piled in tropical eastern Pacific poleward propagation along off the coast of southern America and cause the anomalous temperature raise in near pole and then lead the sea ice in Amundsen sea , Bellingshausen sea and Antarctic peninsula to decrease where the obvious decrease of the sea ice since 80’ decade has close relation to the frequently appearance of E1 Nino. 相似文献
3.
Tidal data from Weizhou, Zhapo, and Shanwei stations between 1969 and 2010 and from five gauging stations in the western Pacific Ocean provided by PSMSL, and the global mean sea level data recorded between December 1992 and December 2010 by TOPEX and Jason satellites were compiled and analyzed. The results show that the perennial mean sea level near Weizhou Island is 211.7 cm(relative to the water gauge zero), and the relative mean sea level rising rate is 2.2 mm yr-1 from 1969 to 2010, which is consistent with the relative mean sea level rising rate recorded at other gauging stations in the western Pacific regions and with the global mean sea level rising rate. The absolute mean sea level rising rate at Weizhou Island is 3.0 mm yr-1 from 1993 to 2010, also conforming with the global mean sea level rising rate(3.1±0.4 mm yr-1) during the same time period. The highest annual tide level at Weizhou Island has a rising rate of 4.6 mm yr-1 and shows a 20-year quasi-periodic variation from 1966 to 2010. The primary cause of the mean sea level rising is global warming. 相似文献
4.
Sub-tidal barotropic current variations coupled with residual sea level fluctuation in the Bohai and Yellow Seas during wintertime are addressed in this study.The temporal evolution and spatial distribution of current fluctuation are investigated using moored acoustic Doppler current profiler data in a three-dimensional numerical model.It is found that a southward current followed by a northward current occurred in the northern Yellow Sea during the fluctuation,concurrent with a significant outflow followed by inflow through the Bohai Strait.The process is consistent from surface to bottom and is coupled with remarkable residual sea level fluctuation.This quasi three-day fluctuation with amplitude 0.2-0.3 m/s leads to 1 m/1.2 m drawdown in the northern Yellow and Bohai Seas,respectively,strongly influencing water exchange between those seas.Because this a prominent feature in the seas,it is necessary to evaluate its effect on fluctuation during winter in future studies,in particular,the northward current during the recovery phase of sea level in the Bohai and Yellow Seas regarding seasonal variation. 相似文献
5.
Silicon limitation on primary production and its destiny in Jiaozhou Bay,China V:Silicon deficit process 总被引：1，自引：0，他引：1
1 INTRODUCTION Land-sourced silicon are continuously input into the sea by rivers. After being assimilated by thousands of living organisms in the sea, silicon sinks with the marine living organisms to the sea bottom, showing a complete silicon transfer process. The study of this dynamic process need clarifying the characteristics of silicon in the sea, which plays an important role in phytoplankton growth, zoo-plankton graze and marine ecosystem. 2 SILICON BEING INDISPENSABLE N… 相似文献
6.
The sea level variabilities, especially the atmosphere-driven sea level variabilities, which are dif ferent in studies on diverse areas and timescales, need to be further documented in the Bohai Bay.Coastal sea level data and coincident meteorological data collected hourly at two observation stations(E1 and E2) in the Bohai Bay, which is a typical semi-enclosed coastal sea in China, are analyzed for the period from 19 August 2014 to 18 November 2014. The sub-sampled low-pass(0.8 cpd) sea levels(SLSLs)at E1 and E2 are almost the same as each other, while the winds are not. On the whole, SLSLs at E1 and E2 are dominantly influenced by the across-shore wind; in detail, the dominant wind orientation at E1 is65° measured clockwise from north, and SLSL at E2 is significantly influenced by the sub-sampled wind(SW) at 55°. Regression of SLSL onto the corresponding SW in dominant orientation and the atmospheric pressure is used to predict SLSL, which make the frequency of occurrences when the predicted total sea level is within 0.15 m from the observed values increase to 66.03% and 58.08% at E1 and E2 from original36.71% and 34.80% without using it, respectively. The results indicate that for the prediction of the total sea level variability in the coastal shallow waters, the SLSL influenced by the atmospheric forcing, including local wind and atmospheric pressure, can be predicted using the multivariable linear regression model. 相似文献
7.
Masayuki Mac Takahashi Kazunori Yamashita 《中国海洋大学学报(英文版)》2005,4(3):219-223
For the supply of fish and shellfish to consumers in fresh condition, clean handling after catch from the sea is essential. According to HACCP （Hazard Analysis and Critical Control Points）, it is important to meet such requirement by keeping fish and shellfish under a certain low temperature and clean conditions after catching. The deep ocean water （DOW） characterized by low temperature and cleanliness has been chosen for fish and shellfish handlings, particularly for salmon, cod, and sea urchin in Town ＇Rausu＇ in Hokkaido, Japan. DOW below 2.9℃ of an amount of nearly 5 000 m^3 is planned to be pumped up every day from a depth of about 350 m, and temporarily stored in a large simulated tank on land. DOW is then supplied to fish boats through hydrants distributed throughout the harbor and used for keeping salmon in clean and cold conditions. Ice made from DOW is also used for lowering temperature if necessary. DOW and ice made from DOW are also used during the transportation of fish and shellfish. The entire system is scheduled to be completed by the summer of 2005. 相似文献
8.
Distribution of suspended matter in seawater in the Southern Yellow Sea is investigated in five regions: 1) the Northern Jiangsu bank, the highest TSM (total suspended matter) content region; 2) the high TSM content region off the Changjiang River mouth; 3) the high TSM content region off the Chengshan Cape; 4) the low TSM region off Haizhou Bay; 5) the central part of the Southern Yellow Sea, a low TSM content region. The vertical distribution of TSM is mainly characterized by a spring layer of suspended matter, written as "suspended-cline" whose genesis is related to storms in winter. In this paper, non-combustible components and grain sizes in suspended matter, relationship between suspended matter and bottom sediments, and salinity in seawater are described. Investigation result shows that, in this area, suspended matter comes mainly from resuspended bottom sediment and secondarily from present discharged loads from rivers and biogenic materials. Discharged sediments from the Huanghe River move arou 相似文献
9.
10.
Pang Yue Fan Dejiang Sun Xiaoxia Sun Xueshi Liu Ming Yang Zuosheng 《中国海洋大学学报(英文版)》2020,19(4):801-810
For a long time, most studies about pyrite have focused on sediments while only a few have focused on pyrite in water. In this study, a method that combines the scanning electron microscopy(SEM) and the energy dispersive X-ray spectrometry(EDS) was used to compare pyrite particles suspended in water to those in associated bottom sediments, both obtained from the mixing zone of the Yangtze Estuary. It was found that the pyrite particles in the two media have similar morphologies and size distributions. The particle morphology mainly includes two types, single crystal and aggregate, and the particle size mainly ranges from 0.5 to 2 μm. The pyrite particles in water exhibit an increase in relative content towards the sea, and their transport and deposit processes are mainly affected by hydrodynamic conditions. It is concluded that the pyrite particles in the suspended matter mainly derived from the resuspension of sediments, which are products of the early diagenesis. Precursor minerals may appear during the formation of pyrite, but are generally restricted by the diagenetic environment and local microenvironment. 相似文献
11.
With the implementation of the GEOTRACES program, the biogeochemical cycle and distribution of tellurium （Te） in marine environments are becoming increasing environmental concerns. In this study, the concentration of dissolved Te in the Changjiang （Yangtze） River estuary and nearby waters was determined in May 2009 by hydride-generation atomic fluorescence spectrometry to elucidate the abundance, dominant species, distribution, and relationship with environmental factors. Results show that： （1） dissolved Te was low owing to its low abundance in the Earth＇s crust, high insolubility in water, and strong affinity to particulate matter; （2） Te（IV） and Te（VI） predominated in surface water. Te（VI） was the dominant species in bottom water, and Te（IV） was the minor species; （3） Horizontally, resulting from low phytoplankton metabolism and the weak reduction from Te（VI） to Te（IV） in the shore, Te（IV） was concentrated in the central zone instead of the coastal region. However, Te（VI） was abundant near the mouth of the Changjiang River where the Changjiang water is diluted and in the area to the south where the Taiwan Warm Current invaded. In the adsorption-desorption process, Te（IV） was negatively related to suspended paniculate matter （SPM）, indicating that it was adsorbed by particulate matter. While for Te（VI）, the positive correlation with SPM suggested that it was desorbed from the solid phase. In the estuary, dissolved Te had a negative correlation to salinity. However, it deviated from the dilution line in high-salinity regions due to the invasion of the Taiwan Warm Current and the mineralization of organic matter. The relationship between Te（IV） and SPM nutrients indicated that it was more bioavailable and more related to phosphorus than to nitrogen. Progress in the field is slow and more research is needed to quantify the input of Te to the estuary and evaluate the biochemical role of organisms. 相似文献
12.
1 INTRODUCTION Porphyra (also called nori in Japanese) is one of the most important algae in aquaculture in the world. In the early 1980’s, basic studies on cell and protoplast isolation, cultivation and “seedling” breeding of Porphyra were conducted in laboratory. Zhao and Zhang (1981) isolated and cultured isolated cells by grinding the nori thallus, and Lu (1983) isolated cells by digesting bacteria. An enzyme isolated from a sea snail, was used to isolate cells and protoplasts (T… 相似文献
13.
Permittivity of a sea foam layer is very important in investigating ocean brightness temperature model. At microwave frequency, the Rayleigh method is developed to estimate the effective permittivity of the sea foam layer. To simplify the tedious calculation of sea foam effective permittivity at L band(1.4 GHz), Pade’ approximation is adopted to fit the sea foam effective permittivity computed by the Rayleigh method. With this fitting formula, a new brightness temperature model of sea foam layer defined by certain geophysical parameters, such as air volume fraction(AVF), sea surface temperature(SST), sea surface salinity(SSS) and thickness of foam layer d, is given. Furthermore, the sensitivities of the brightness temperature model to SST, SSS, d and AVF of a sea foam layer at L band are discussed. The sensitivities are ranked from most to least in the order:(1) d;(2) AVF;(3) SSS;(4) SST. This result indicates that the measurement errors of d and AVF have significant impacts on the retrievals of SSS and SST. With the experimental brightness temperature data, the SSS and AFV are retrieved by cost function. 相似文献
14.
XUEChunting 《中国海洋大学学报(英文版)》2005,4(2):115-123
Studies on land loss in Tuvalu reveal the following findings. Although both sea level rise and coastal erosion can cause land loss in the tropic Pacific oceanic islands, their mechanisms are different. When sea level rises, the low elevation coastal zone submerges and the erosion datum plane rises, the beach process progresses normally as always, resulting in no beach sediment coarsening. When the sea level is stable, coastal erosion removes finer sediment from reef flat, beach and land, resulting in beach sediment coarsening. The human-induced coastal erosion in the tropic Pacific oceanic islands has the following features. 1) Erosion occurs or intensifies immediately after inappropriate human activities. 2) It occurs near the places having human activities and places related to the above places in sediment supply. 3) It often occurs on original prograding or stable coasts (on lagoon coasts for atolls) because there are more coastal engineering projects and other human activities on such coasts. 4) It is chronic, covering a long period of time. The coastal geological events in Tuvalu islands do not accord with the features resulted from sea level rise but do accord with the features resulted from coastal erosion, particularly from human-induced erosion. The land loss in Tuvalu is mainly caused by inappropriate human activities including coastal engineering and aggregate mining, and partly caused by cyclones. Moreover, all recent measurements (satellite altimetry,thermosteric sea level data and tide observations) so far have not been able to verify any sea level rise around Tuvalu islands. 相似文献
15.
Suspended particle samples were collected at 11 stations on the shelf and slope regions of the Chukchi Sea and the central Arctic Ocean during the fifth Chinese National Arctic Research Expedition （summer 2012）. The particle concentration, total organic carbon （TOC）, total nitrogen （TN） and the isotopic composition of the samples were analyzed. The suspended particle concentration varied between 0.56 and 4.01 mg.Ll; the samples collected from the sea ice margin have higher concentrations. The organic matter content is higher in the shelf area （TOC： 9.78%-20.24%; TN： 0.91‰-2.31%）, and exhibits heavier isotopic compositions （δ13C： -23.29‰ to -26.33‰ PDB; δ15N： 6.14‰-7.78‰）, indicating that the organic matter is mostly marine in origin with some terrigenous input. In the slope and the central Arctic Ocean, the organic matter content is lower （TOC： 8.06%- 8.96%; TN： 0.46%-0.72%）, except for one sample （SR15）, and has lighter isotopic compositions （δ13C： -26.93‰ to -27.78‰ PDB; δ15N： 4.13‰-4.84‰）. This indicates that the organic matter is mostly terrestrially-derived in these regions. The extremely high amount of terrigenous organic matter （TOC： 27.94%; TN： 1.16%; δ13C： -27.43‰ PDB; δ15N： 3.81‰） implies that it was carried by transpolar currents from the East Siberian Sea. Material, including sea ice algae, carried by sea ice are the primary source for particles in the sea ice margins. Sea ice melting released a substantial amount of biomass into the shelf, but a large amount of detrital and clay minerals in the slope and the central Arctic Ocean. 相似文献
16.
Under suitable conditions of tidal current and wind, underwater topography can be detected by synthetic aperture radar (SAR) indirectly. Underwater topography SAR imaging includes three physical processes: radar ocean surface backscattering, the modulation of sea surface short wave spectrum by the variations in sea surface currents, and the modulation of sea surface currents by the underwater topography. The first process is described usually by Bragg scattering theory because the incident angle of SAR is always between 20°-70°. The second process is described by the action balance equation. The third process is described by an ocean hydrodynamic model. Based on the SAR imaging mechanism for underwater topography, an underwater topography SAR detection model and a simplified method for its calculation are introduced. In the detection model, a two-dimensional hydrodynamic model – the shallow water model is used to describe the motion of tidal current. Due to the difficulty of determining the expression of SAR backscattering cross section in which some terms can not be determined, the backscattering cross section of SAR image used in the underwater topography SAR detection is pro-processed by the simulated SAR image of the coarse-grid water depth to simplify the calculation. Taiwan Shoal, located at the southwest outlet of Taiwan Strait, is selected as an evaluation area for this technique due to the occurrence of hundreds of sand waves. The underwater topography of Taiwan Shoal was detected by two scenes of ERS-2 SAR images which were acquired on 9 January 2000 and 6 June 2004. The detection results are compared with in situ measured water depths for three profiles. The average absolute and relative errors of the best detection result are 2.23 m and 7.5 %, respectively. These show that the detection model and the simplified method introduced in the paper is feasible. 相似文献
17.
On small-meso scale, the sea ice dynamic characteristics are quite different from that on large scale. To model the sea ice dynamics on small-meso scale, a new elastic-viscous-plastic （EVP） constitutive model and a hybrid Lagrangian- Eulerian （HLE） numerical method are developed based on continuum theory. While a modified discrete element model （DEM） is introduced to model the ice cover at discrete state. With the EVP constitutive model, the numerical simulation for ice ridging in an idealized rectangular basin is carried out and the results are comparable with the analytical solution of jam theory. Adopting the HLE numerical model, the sea ice dynamic process is simulated in a vortex wind field. The furthering application of DEM is discussed in details for modeling the discrete distribution of sea ice. With this study, the mechanical and numerical models for sea ice dynamics can be improved with high precision and computational efficiency. 相似文献
18.
ZHANG Mingyu LIU Xiting XU Fangjian LI Anchun GU Yu CHANG Xin ZHUANG Guangchao ZHANG Kaidi BI Naishuang WANG Houjie 《中国海洋大学学报(英文版)》2023,(5):1300-1312
The East China Sea(ECS), which is located in the transitional zone between land and ocean, is the main site for the burial of sedimentary organic carbon. Despite good constraints of the modern source to the sinking process of organic carbon, its fate in response to changes in climate and sea level since the last deglaciation remains poorly understood. We aim to fill this gap by presenting a high-resolution sedimentary record of core EC2005 to derive a better understanding of the evolution of the... 相似文献
19.
The history of the East Asian monsoon(EAM) since Last Glacial Maximum is reconstructed based on records in a sediment core retrieved from the northern South China Sea. The provenance of organic carbon and the EAM's evolution are investigated using combined organic carbon, grain size, and AMS 14 C dating analysis. Responding to the strong winter monsoon, the marine organic matter was dominated in the sediments, and δ13 C of organic matter was high during the last glacial period. During the Holocene, the primary productivity decreased and the dilution effect of riverine inorganic clastics strengthened. Accordingly, the total organic carbon contents and δ13 C values decreased, and terrestrial organic matter content increased in the core sediments. The 4 μm grain size fraction, as the environmental sensitive grain size component, is determined to reconstruct the paleoclimatic records. During the last glacial period, the contents of 4 μm grain size component were mainly controlled by the sea level changes. Upon the Holocene, the influence of the sea level changes weakened and the roles of current system and provenance strengthened. The correlation between the EAM and solar insolation forcing is also discussed in this paper. 相似文献
20.
Lü Xianqing 《中国海洋大学学报(英文版)》2007,6(4):339-344
A two-layer pollutant advection-diffusion model is built to investigate the pollutant transport in the sea area around Maidao off Qingdao coast. An adjoint data assimilation technique is applied to estimate the optimal values of the model parameters. The experimental results on the initial field of pollutant indicate that the distribution of Chemical Oxygen Demand (COD) concentra- tion is sensitive to the horizontal eddy diffusivity. An appropriate value of horizontal eddy diffusivity is necessary in order to depict the influence of the initial field precisely, and it is also essential to the simulation of the advection-diffusion process of the pollutant. By inversion of the model parameters and optimization of the initial COD concentrations, the simulation results are improved sig- nificantly. The cost function is reduced to 40% of its first step value. The average misfit between the model outputs and the observa- tions in the upper layer decreases from 0.46 to 0.25 mg L-1, and that in the lower layer decreases from 0.22 to 0.14 mg L-1. 相似文献