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Post-rift subsiding anomalies have been discovered in many basins in the northern continental margin of South China Sea, of which Baiyun Sag is a typical one. We used software Temis Suite 2007 to build the backstripping model of three NNW—SEE-oriented seismic profiles crossing the Baiyun Sag, and analyzed the post-rift subsidence. The results show that the Baiyun Sag experienced anomalous post-rift subsidence. Compared with the Mckenzie's classic port-rift subsidence model, the Main Baiyun Sag subsided over 2.6 km deeper and the Southern Baiyun Sag subsided nearly 2 km. An accelerated subsidence stage could be conducted during 16.5~10.5 Ma, which might relate to the end of sea-floor spreading in the South China Sea. The ductile extension and extreme quick and thick deposition in the Baiyun Sag indicate that the lower-crustal flow might have been the mechanism for the anomaly subsidence.

Numerous sedimentary thickness data provided by seismic profiles were collected and drawn into the sedmimentary isopach in the East China Sea. The residual gravity anomalies were obtained by subtracting the gravity effect generated by the sediments from the complete Bouguer gravity anomalies. Depths to the Moho of the East China Sea were inversed from the residual gravity anomalies with constraint of the seismic penetration depths to the Moho. Our results show that depths to the Moho change between 25 km and 28 km gently and crustal thicknesses change between 14 km and 26 km on the East China Sea Shelf, depths to the Moho change between 16 km and 26 km and crustal thicknesses change between 12 km and 22 km within the Okinawa Trough. Crusts at the east of the East China Sea Shelf Basin and the south of Okinawa Trough are thinned evidently, and their crustal stretching factors are up to 2.6 and 3, respectively. Preliminary analyses suggest that the crust of Okinawa Trough is mainly transition type and there is no obvious evidence to prove the existence of oceanic crust.

Based on the OAFlux3, the NCEP/NCAR reanalysis data for the period of 1985-2008 and the daily data of summer precipitation at 108 observational stations of eastern China, the relationship between the inter-annual variations of summer precipitation in eastern China and the latent heat flux anomalies in the East China Sea (ECS) are analyzed by using the composite and the linear regression analysis methods. The mechanism of summer precipitation anomalies in eastern China caused by the latent heat flux in ECS is also further analyzed from the perspective of atmospheric zonal and meridional circulation and water vapor transport in East Asian area. In order to focus on the inter-annual timescles, the long-term trend in the variations of laten heat flux in ECS, summer precipitation in eastern China and atmospheric circulation over East Asia have been removed in this study. The analyzed results show that the latent heat flux displays strong inter-annual variations signal in ECS and is closely related to summer precipitation in eastern China. When the latent heat flux in ECS is above (below) normal in summer, an anomalous anticyclonic (cyclonic) circulation appears over the northwest Pacific and the northeasterly (southwesterly) anomalies appear over eastern China, which are unfavorable (favorable) for the northward transportation of water vapor and result in more (less) water vapor in South China and less (more) water vapor in the middle and lower reaches of the Changjiang River and north areas. Furthermore, the atmospheric zonal and meridional circulations will be manifested as a downward (upward) motion with a divergence (convergence) in low level and a convergence (divergence) in upper level can appear over the middle and lower reaches of the Changjiang River, which may result in less (more) summer rainfall. While in South China, the atmospheric zonal and meridional circulations will be manifested as upward (downward) anomaly and convergence (divergence) at low levels,which may result in more (less) summer rainfall. The variations of atmospheric zonal and meridional circulation and water vapor transportation over East Asia caused by the latent heat flux anomalies in ECS could lead to the precipitation anomalies in the above mentioned area. It is suggested that the abnormal change of the latent heat flux in ECS may be one of the most important factors for the abnormal of summer rainfall in East China on the inter-annual timescales.

In this paper, a mixed layer heat budget analysis is used to investigate the possible causes of ENSO asymmetry by analyzing the HadISST data, the SODA and NCEP reanalysis data. The significant positive skewness of SSTA appears in the eastern Pacific by analyzing the SSTA data. This feature indicates the amplitude of El Nio is larger than that of La Nia. A mixed layer heat budget analysis indicates that there may be 3 possible reasons for the asymmetry of ENSO events. The first is attributed to the nonlinear temperature advection. The horizonal nonlinear advection tends to enhance the mixed layer temperature tendency during the developing phase both in El Nio and La Nia, and contribute to the positive skewness in the eastern Pacific. The second possible reason is attributed to the nonlinear response of the subsurface temperature anomaly to the variations of the thermocline depth anomaly. Because of the structure of vertical temperature distribution in the eastern Pacific, the subsurface temperature is more sensitive to the positive thermocline depth anomaly than the negative thermocline depth anomaly. This can cause the subsurface temperature anomaly larger in El Nio events than in La Nia events, and enhance the upper ocean temperature skewness through the term -wT′_z. The third is attributed to the positive skewness of equatorial zonal wind stress in the central Pacific, which may cause the positive SSTA skewness in the eastern Pacific. The positive skewed zonal wind anomaly in the central Pacific creates the positive skewness of the thermocline depth anomaly in the eastern Pacific, make the asymmetry of the subsurface temperature anomaly, and influence the skewness of the SSTA through the term -wT′_z.

Phytoplankton is a major component of marine water, an insight investigation of its inherent optical properties is the foundation of understanding the principle of light transferring in water. In the last 30 years, focus was mainly on the absorption measurement and comparison of different algae, very few researchers had a detailed study on their scattering properties. In this paper, a method based on spectrometer was developed to measure the total scattering and backscattering coefficient of algae containing solution. The verification procedure of the method was carried out by measuring the scattering and backscattering results of polystyrene latex micro beads with known size distribution and refractive index. The results showed a maximum deviation of 4% for scattering in the visible spectrum and around 20% higher for backscattering in the red spectrum but quite good consistency in other regions. The method was then used to measure the scattering and backscattering features of two bloom algae in East China Sea: Skeletonema costatum and Prorocentrum donghaiense. It shows that the two algae had comparable amplitudes in both scattering and backscattering cross section, but Skeletonema costatum had a quite opposite scattering pattern to Prorocentrum donghaiense, whose scattering decreases with increasing wavelength. This could be attributed to the different cellular components which determine whether it follows normal or anomalous dispersion for the refractive index. Both algae have a regional minimum of scattering around 670 nm, which was due to the anomalous dispersion and the strong absorption of chlorophyll a. The backscattering cross section for the two algae were similar in both amplitude and spectrum pattern, Prorocentrum donghaiense had a higher but smoother backscattering spectrum. It'd demonstrated that the backscattering spectrum is well influenced by absorption of cellular pigments. Finally, the backscattering to scattering ratio was 0.723% for Skeletonema costatum and 1.104% for Prorocentrum donghaiense, the absolute value of backscattering cross section were 0.001 43 m²/mg and 0.001 74 m²/mg respectively.

Optical properties of Chromophoric Dissolved Organic Matter (CDOM) have played an important role in quantitative water-color remote sensing retrieval. The optical properties of CDOM in coastal waters of Changjiang River Estuary were investigated in June of 2011. This area is affected by terrigenous factor strongly with different hydro-dynamic characteristics. CDOM absorption coefficient and spectral slope were got through sampling, laboratory measurements and subsequent data processing. Then, CDOM absorption cofficient and spectral slope were discussed. CDOM absorption coefficients at 440 nm [a(440)] varied between 0.21 and 0.85 m^-1, with an average value of 0.44 m^-1.In addition, the spectral slope, S_g varied between 0.013 3~0.016 7 nm^-1, with an average value of 0.014 nm^-1. Significant spatial difference in absorption cofficient and spectral slope was observed varied tremendously in the estuary and the offshore area. The higher absorption coefficients of the cruise appeared in the estuary area while the lower spectral slope of the cruise appeared in the area which is greatly influenced by the terrestrial sources; the lower absorption coefficients appeared in the offshore area while the higher spectral slope of the cruise appeared in the area which is greatly influenced by the mixing of terrestrial humic sources and seawater. A significant positive relationship between salinity and a(440) was found in the whole area showing conservative behavior of CDOM. There was a good correlative relationship between the spectral slope S_g and salinity in the whole area, which also reflected conservative behavior of CDOM.

Benefit from the ability of displaying fine topography features of multi-beam sounding system, a special seabed landform drew much attention of the researchers during the investigation at the north Yellow Sea. This seabed landform was a kind of micro ring depression quite different from the submarine depressions reported previously. It developed at the plain seafloor in the water depth of 55 m to the south of the Changshan Archipelago, circular or irregular ellipse shape, with shallow grooves along the edge, protrusion or depression in the central. Each depression has different size, most of which has a major axis of about 2 km, with the shallow groove along the edge of 200~300 m wide and 0.25~2 m depth. Several micro depressions arranged in a row, with the regional trend of NW—SE or NE—SW.
The topography form and features of the micro ring depressions were described in detail in this paper based on the multi-beam survey data. They were divided it into three types with different distributions and morphologies. TypeⅠdistributed at the northeast of the area, circular or elliptical in plan view, with protrusion in the central. TypeⅡdistributed at the southeast of the area, to the north of TypeⅠarea, elliptical or elongated in plain view with depression in the central. Type Ⅲ distributed at the southwest of the area, curved in plain view, and much shorter and shallower than the previous ones. Given the circular or ellipse morphology, the annular micro depression may relate to the sub-bottom gas leakage, which can produce pockmarks with circular or elliptical shape. Meanwhile, shallow gas leakage produced by sub-bottom profile records and the deposit of peat discovered in boreholes 8 km south to the study area can support this opinion.
Therefore, it is possible that the micro ring depressions were formed by sub-bottom shallow gas leakage, and be transformed by bottom current and submarine slumping. If the suggestion can be confirmed, it will be great significance to the study of environmental evolution of the northern Yellow Sea and will provide new inspiration to the oil and gas exploration in this area.

Ultra-short baseline is the necessary device to achieve the accurate positioning of towing equipment, and it is also the important equipment to do the deep-sea resource research in the international seabed area at the present. Because of the influences of acoustic signal propagation loss,multipath effect and other equipment noise, underwater positioning data has many outliers, which has seriously affected the credibility and the use of positioning data.To solve this problem, we propose and implement a correction algorithm based on correlation analysis to reject outliers and random regression which fill and correct positioning data. We use positioning data measured from the international seabed area to validate the reliability of the algorithm.At the same time, we use simulation comparison method for small scale and short time positioning data forecast, and therefore a good result has been achieved. The experimental results show that the algorithm is fast and effective. It is expected to be applied to the international seabed area survey, and can provides direct service to the international seabed resources investigation for accurate positioning equipment.

Suspended particulate matter in seawater was treated separately by high pressure digestion using sulfuric acid-potassium persulfate as the oxidant and soaking extraction in 1 mol/dm³ hydrochloric acid in order to dissolve total phosphorus and inorganic phosphorus respectively. The dissolved phosphorus was determined using phosphomolybdate blue spectrophotometry to calculate total and inorganic phosphorus in seawater suspended particulate matter and in sediments. Organic phosphorus was subsequently obtained by subtracting inorganic phosphorus from total phosphorus. The relative standard deviation was less than 1.44% when the concentration of PTP and PIP were (632.4～651.7)×10^－6 and (436.6～452.6)×10^－6 respectively. The recovery rate of PTP, PIP and POP were 97.2%～101.3%, 97.8%～100.4% and 97.3%～102.3% respectively. This analytical method can be used for determination of different forms of phosphorus in marine and estuarine sediment and in suspended particulate matter.

In the present study, the bioaccumulation of lead in four species of seashell including Tegillarca granos, Ruditapes philippinarum, Sinonovacula constricat canarck and Monodonta labio were investigated in a semi-static system. The seashell were cultivated in seawater contaminated with different lead concentrations (0.001 0,0.003 5,0.006 0,0.011 0,0.026 0,0.051 0 mg/L, respectively). The content of Pb was analyzed in muscle tissue using atomic absorption spectrometry with microwave digestion in 0, 1, 3, 5, 10, 15, 20, 25 and 30 d, respectively.The results indicated that the four species of seashell could accumulate lead from aquatic environment. The bioaccumulation of Tegillarca granosa was obvious while the concentration of lead in seawater was higher than 0.003 5 mg/L. The lead concentration in Monodonta labio increased significantly while the concentration of lead in seawater was higher than 0.006 mg/L. Similarly, the lead content in Ruditapes philippinarum and Sinonovacula constricat canarck exhibited significant increases while the concentration of lead in seawater was higher than 0.011 mg/L. As a whole, the levels of Pb in seashell increased with the increase of those in seawater and the enrichment time. While the concentraion of lead in seawater was lower than 0.051 mg/L, the levels of lead in seashell showed significant decrease in 3 d and continued to increase after 5~10 d. Finally, the mechanisms of seashell response to lead enrichment were also investigated.

According to the arrangement parameters of attracting lamps on the light purse seine vessels, the illumination distribution underwater was calculated. The results showed that in the case of the total power of fishing lamps being 180 kW in main light vessel, the equal illumination curve of 10 lx could reach 56 m in horizontal direction in the farthest, and did not exceed 20 m in vertical direction. In 40 m vertical and 40 m horizontal distance from the ship, the illumination was about 0.01 lx. In the second case of the total power of fishing lamps being 120 kW in vice light vessel, the equal illumination curve of 10 lx could reach 46 m in the horizontal farthest,and did not exceed 20 m in vertical direction. In 40 m vertical and 33 m horizontal distance from the ship, the illumination was about 0.01 lx. In the third case of the total power of fishing lamps being 40 kW in net vessel, the equal illumination curve of 10 lx could reach 45 m in the horizontal farthest, and did not exceed 15 m in vertical directiong. In 35 m water depth and 38 m horizontal distance from the ship, the illumination was about 0.01 lx. As to the configuration of fish lamp, the present current configuration of main light vessel is good, but if we increase the space to 0.26 m, and increase the lamps' height to 5 m, 1.6% of the effective water volume can be increased. The present current configuration of vice light vessel is good, but if we decrease the space between to 0.28 m, and increase the lamps' height to 5 m, 2.1% of the effective water volume can be increased. And the present current configuration of the net vessel is also good, but if we decrease the space to 0.64 m, and increase the lamps' height to 9 m, 1.7% of the effective water volume can be increased. The results also show that it is not very effective way to improve the light induced range of the boat by greatly increasing the total power of fishing lamps.