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1.
Surface water was collected from the Jiulong Estuary for determination of activity concentrations of uranium isotopes in different size fractions, namely, greater than 53, 10 -53, 2 - 10, 0.4 -2 μm, 10 000 u -0.4 μm and less than 10 000 u fractions by microfihration and cross-flow uhrafiltration technologies. Results indicated that most of the dissolved uranium （ 〈 0.4 μm） exis- ted in the low molecular mass fraction （ 〈 10 000 u）, and the colloidal uranium-238 （10 000 u -0.4 μm） only contributed less than 1% of the dissolved uranium-238. The fractions of colloidal uranium in the dissolved phases decreased with the increasing sa- linity. A positive linear relationship between uranium-238 activities and salinities was observed for the dissolved, colloidal and low molecular mass fractions, indicating a conservative behavior of uranium in the Jiulong Estuary. In the particulate phases （ 〉 0.4 μm）, the partitioning of uranium isotopes among different size fractions was controlled by the partitioning of particle concentrations. In the regions with salinities below 20, the partitioning of uranium-238 among different size fractions was as follows： 10 - 53 μm 〉 2 - 10 μm 〉 0.4 - 2 μm greater than above 53 μm. However, the order at the offshore station with salinities above 30 changed as follows ： 0.4 - 2 μm 〉 10 - 53 μm 〉 2 - 10 μm greater than above 53 μm. The fraction of the 0.4 - 2 μm particles increased at the offshore station, suggesting the increased contribution of the authigenic uranium. The activity ratio of uranium-234 to uranium-238 in the dissolved phases, including the low molecular mass fraction and the colloidal fraction, was larger than unity, showing the occurrence of excess uranium-234. In contrast, the activity ratio of uranium-234 to uranium-238 in all size fractions of the particulate phase was close to the equilibrium value （1.0）. The observed different values of the activity ratio of uranium-234 to uranium-238 in the dissolved phase and the partic  相似文献   

2.
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   

3.
In this paper, the recent development in modeling seabed dissipative mechanisms in shallow water is reviewed. Specifically, laminar and turbulent boundary layer solutions as well as viscous mud flow solutions under transient waves are presented. These analytical solutions are compared with experimental data for both solitary waves and cnoidal waves. Very goed agreement is ohtained. The Boussinesq equations with boundary layer effects and the muddy seabed effects are also shown.  相似文献   

4.
The purpose of this study is to detail the ecological characteristics of phytoplankton in waters around the Daya Bay Nuclear Power Station in Guangdong (GNPS) (Fig. 1) in spring, the bloom period of algae. The collections with a small temporal scale of every three days were made during 30 cruises from March to May in 1987. Such an investigation has never been carried out before in China except that the seasonal distribution and composition of phytoplankton in these regions were reported in  相似文献   

5.
Silting in the Lower Courses of Tidal Sluices in China   总被引：2，自引：0，他引：2  
Serious sediment deposition often occurs after the construction of tidal sluices in snrall or medium-sized tidal muddy estuaries, so desilting or dredging is needed to meet the demands of flood diseharge, saltwater retaining, and navigation in those areas. In this paper, the problem of sediment deposition induced by construction of tidal sluices is analyzed.Different problems of silting near tidal sluices for different types of estuaries are summed up. at the same time, corresponding methods are given to solve these probleras, and a few successful examples are also given. The idea of comprehensive regulation and utilization of estuaries is put forward, and some proposals for solution of sediment deposition in this kind of estuaries are made.  相似文献   

6.
Winter convection in the Irminger Sea leading to the formation of Labrador Sea Water (LSW) is analyzed using CTD data collected along the 59.5° N transatlantic section in 2004–2014, winter Argo data from 2012–2014, and daily North American regional reanalysis (NARR). The interannual variability of LSW in the Irminger Sea is investigated. The dissolved oxygen saturation rate of 93% is used to indicate maximal local convection depth. It is shown that the deepest convection (up to 1000 m) resulting in the largest LSW volume that formed in the Irminger Sea in 2008 and 2012. These years were characterized by numerous storms with anomalously strong turbulent heat loss from the ocean to the atmosphere and negative air temperature to the east of the southern tip of Greenland in January–March. LSW became warmer by 0.42°C, saltier by more than 0.03 PSU, and more oxygenated by 8 µmol/kg between 2004 and 2014. A strong LSW decay in the Iceland Basin is also noted.  相似文献   

7.
In this study,cored sediment samples collected by the Jiaolong Submersible at 6779 m depth from the hadal zone of the Yap Trench in May 2016 were sliced in 1-cm interval from top to bottom,and lipids in each sediment layer were quantitatively and qualitatively analyzed.The vertical distribution profiles of the lipids in the sediment sample,their main existing forms,and their possible sources were investigated.The results show that the concentration of lipid in the surface sediment was the highest with the carbon number from 12 to 27,dominated by medium and short-chain lipids.The total concentration of fatty acids in surface sediment was much higher than those in the offshore and deep-sea areas,being up to 325.77μg/g due to the funnel effect caused by the“V”terrain of the trench.Fatty acid 18:0 was the most abundant lipids in the sediment sample.Abnormal high concentrations of fatty acid 18:1ω7 and alkanes indicated the existence of hydrothermal fluids in the study area.In addition,saturated fatty acids and monounsaturated fatty acids existed mainly in free form,and polyunsaturated fatty acids existed mainly in bound form.Most of the alkanes were in bound form,and their major source was autochthounous input.The carbon number of alcohols in the sediment sample ranged from 12 to 20,mainly existed in bound form.The source of fatty acids was mainly autochthonous input,and the neutral lipids had both marine and terrestrial origin.This is the first study of lipids in hadal sediment of the Yap Trench.The results will promote deeper understanding of organic carbon cycle in marine environment.  相似文献   

8.
After many years＇ endeavor of research and application practice, the ocean color remote sensing in China has been growing into a new technique with valuable practicality from its initiate stage of trial research. With the aim of operational service, several kinds of ocean color remote sensing application systems have been developed and realized the long-term marine environmental monitoring utilizing the real-time or near real-time satellite and airborne remote sensing data. New progresses in the technology and application of ocean color remote sensing in China are described, including the research of key techniques and the development of various application systems. Meanwhile, according to the application status and demand, the prospective development of Chinese ocean color remote sensing is brought forward. With Chinese second ocean color satellite （ HY-1 B） orbiting on 11 April 2007 and the development of airborne ocean color remote sensing system for Chinese surveillance planes, great strides will take place in Chinese ocean color remote sensing application with the unique function in marine monitoring, resources management and national security, etc.  相似文献   

9.
Ｐｈｉｌｌｉｐｓｉｔｅｉｎｄｅｅｐ－ｓｅａｓｅｄｉｍｅｎｔｓ￥ＰｅｎｇＨａｎｃｈａｎｇａｎｄＬｉｕＺｈｅｎｇｋｕｎ（ＲｅｃｅｉｖｅｄＭａｒｃｈ５，１９９３；ａｃｃｅｐｔｅｄＡｕｇｕｓｔ１４，１９９３）Ａｂｓｔｒａｃｔ：──Ａｐｈｉｌｌｉｐｓｉｔｅａｓ...  相似文献   

10.
- In this paper, some problems in the design of the breakwater for Dayaowan port area are described including the optimal selection of the layout plan of the breakwater; the selection of structural type of the breakwater, the concrete block type for bank protection, the reversed L-shape parapet; the elevation of the parapet; the stability test of the whole revetment; as well as wave absorbing effects of the perforated  相似文献   

11.
ＩＮＴＲＯＤＵＣＴＩＯＮＴｈｅＢｏｈａｉＳｅａｉｓａｎｉｎｎｅｒｓｅａｏｆＣｈｉｎａａｎｄａｓｍｏｏｔｈｂｏｒｄｅｒｏｆｔｈｅｗｅｓｔｅｒｎＰａｃｉｆｉｃＯｃｅａｎ ,ｗｉｔｈａｎｅｘｔｅｎｓｉｏｎｏｆａｂｏｕｔ 5 5 0ｋｍｆｒｏｍｎｏｒｔｈｔｏｓｏｕｔｈａｎｄ 30 0ｋｍｆｒｏｍｅａｓｔｔｏｗｅｓｔ.Ｉｔｉｓｓｔｒｏｎｇｌｙｔｉｄａｌｌｙｉｎｆｌｕｅｎｃｅｄａｎｄ ,ｍｏｒｅｏｖｅｒ,ｂｙａｔｍｏｓｐｈｅｒｉｃｄｒｉｆｔｉｎｇｏｆｗｉｎｄｓｔｒｅｓｓａｎｄｃｕｒｒｅｎｔｓｏｆｗａｒｍｔｈａｎｄｓａｌｔ.Ｔ…  相似文献   

12.
Distribution of fecal coliform group in the coastal waters in Xiamen Harbor was investigated. The detectable numbers of fecal coliform group were generally 10~2—10~3/1000 ml or 10~3—10~4/1000ml, except more than 10~4/1000ml at a few stations contaminated severely. The numbers were influenced by tidal change, decreasing in the order of low tide>ebb  相似文献   

13.
I\TRODLCTIO\In ootal enviroaments, the degradation of sedimentaIy organic matter was the main pro-cess of the biQgaxhemistry cyclc of nutrients, which controlled not only the bury efficiency oforganic carbon but a1so the nutrients flux to overlylng water (Aller, l980). The rnain mecha-nism of whneralization of sediment was organic rnatter degradation such a-s biolOgic and redOxprocesses, these reactions oould convert sedirnentary organic rnatter into nutrients, then releaseto the intersti…  相似文献   

14.
1Introduction Besidestheprecipitationandriverdischarges,the watersinthePacificOceanandtheAtlanticOceanare thesourcesoftheArcticOceanwater.TheAtlantic waterenterstheArcticOceanviatheFramStraitand theBarentsSea.Foritsdenserfeatureduetohigh salinity,mostofitsinkstothenorthofSvaldbardand circulatesinallthedeepbasinsintheArcticOcean, formingthedeepandbottomwatersoftheArcticO- cean(Aagaardetal.,1985;Rudelsetal.,1999).The BeringStraitistheonlychannelforthePacificwater toflowintotheArcticOce…  相似文献   

15.
A short survey prepared by the Russian Commission on Atmospheric Radiation contains the most significant results of works in the field of atmospheric-radiation studies performed in 2007–2010. It is part of the Russian National Report on Meteorology and Atmospheric Sciences prepared for the International Association on Meteorology and Atmospheric Sciences (IAMAS). During this period, the Russian Commission on Atmospheric Radiation, jointly with concerned departments and organizations, ran the conference “Physics and Education,” dedicated to the 75th anniversary of the Department of Physics at St. Petersburg State University (2007); the International Symposium of CIS Countries “Atmospheric Radiation and Dynamics” (2009); and the 5th International Conference “Atmospheric Physics, Climate, and Environment” (2010). At the conferences, central problems in modern atmosphere physics were discussed: radiative transfer and atmospheric optics; greenhouse gases, clouds, and aerosols; remote methods of measurements; and new measurement data. This survey presents five directions covering the whole spectrum of investigations performed in the field of atmospheric radiation.  相似文献   

16.
Role of mangrove in mercury cycling and removal in the Jiulong Estuary   总被引：4，自引：0，他引：4  
Baseline of mercury in mangrove swamp The mercury content in sediments in the Jiulong Estuary was determined in 1984 and 1985(Table 1). The highest content of mercury in sediments (300×10~(-9)) was found in Ditou, contrast-ing strongly with the low content of 36×10~(-9) in Port Dongzhai in the Hainan Island. Tab1e 1 showsthat the average content of mercury in sediments in the Jiulong Estuary is 140×10~(-9) and the averageof four areas is 72×10~(-9). This value means that these areas have not been heavily contaminated by  相似文献   

17.
ＳｔｕｄｉｅｓｏｎｍａｒｉｎｅｎａｎｏｄｉａｔｏｍｓｉｎＦｕｊｉａｎｃｏａｓｔａｌｗａｔｅｒｓｏｆＣｈｉｎａｉｎｗｉｎｔｅｒ￥ＬｉｕＳｈｉｃｈｅｎｇ；ＧａｏＹａｈｕｉａｎｄＣｈｅｎｇＺｈａｏｄｉ（ＲｅｃｅｉｖｅｄＤｅｃｅｍｂｅｒ２２，１９９４；ａｃｃ...  相似文献   

18.
The present paper deals with the ultrastructural changes of oocyte in the process of maturing in pen shell Atrinapectinata Linne. When it develops from the antecedent growth period to the accelerating growth period the annulate lamellae emerge, the RER better develop, the yolk granules with single and double layer membrane and are visible. In the well-developed mitochondria there is yolk stored. The Golgi vacuoles are brewing yolk granules. At the mature period the annulate lamellae and the Golgi bodies disappear, and there are only a few RER and mitochondria with poor cristae in the cytoplasm. All these might be well used for judging the maturity of the ootids in the process of the artificial propagation.  相似文献   

19.
Samples of sediments and the overlying water were collected in the Qi'ao Island coastal zone, the Zhujiang (Pearl River) Estuary (ZE). Denitrification rates, sediment oxygen demand (SOD) , and fluxes of inorganic nitrogen compounds were investigated with N2 flux method, using a self-designed continuous flow through and auto-sampling system. The results indicate that the denitrification rates varied between 222 and 908 μmol/(m2·h) with an average of 499 μmol/(m2·h). During incubation, the sediments absorbed dissolved oxygen in the overlying water with SOD ranging from 300 to 2 363 μmol/(m2·h). The denitrification rates were highly correlated with the SOD (r2 =0.77) regardless of the NO3- + NO2- concentrations in the overlying water, organ- ic carbon contents in sediments and water temperature, suggesting that the SOD was probably the main environ-mental factor controlling the denitrification in the Qi'ao Island coastal zone. There was a net flux of NO3- + NO2-into the sediments from the overlying water. The NH4+ flux from sediments into water as the result of mineraliza-tion was between 12. 3 and 210. 3 μmol/(m2·h) ,which seems limited by both organic carbon content in sedi-ment and dissolved oxygen concentration in the overlying water.  相似文献   

20.
A short survey prepared by the Russian Commission on Atmospheric Radiation contains the most significant results of work in the field of atmospheric-radiation studies performed in 2011–2014. It is part of the Russian National Report on Meteorology and Atmospheric Sciences prepared for the International Association on Meteorology and Atmospheric Sciences (IAMAS)1. During this period, the Russian Commission on Atmospheric Radiation, jointly with the concerned departments and organizations, organized two International Symposiums on Radiation and Dynamics (ISARD-2011 and ISARD-2013). At these conferences, the central problems in modern atmospheric physics were discussed: radiative transfer (RT) and atmospheric optics; greenhouse gases, clouds, and aerosols; remote methods of measurements; and new measurement data. This survey presents six directions covering the whole spectrum of investigations performed in the field of atmospheric radiation.  相似文献   

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