Volume articles

Typhoon Rammasun was the strongest typhoon that hit the South China in the past 41 years since 1973. It increased rapidly over the South China Sea (SCS) before the landfall. In early summer, the SCS is warm enough to support the increase of a typhoon in every year. However, the Western Pacific Subtropical High (WPSH) which steers the trajectories of tropical storms in the western Pacific deviates most tropical storms from the SCS. But, recently, the WPSH experiences a westward extension. Analysis shows that WPSH in early summer of 2014 took a more southward and more westward position than it did in the past several decades. As a result, Typhoon Rammasun was guided into the SCS through Philippine, which was an uncommon tropical storm track in July. In the SCS, Typhoon Rammasun was nourished by the warm ocean and became a super typhoon within only 26 hours. As the implication of this study, if the westward extension of WPSH remains and continues, it is reasonable to expect that more tropical storms enter the warm SCS and get intensified in early summer. Consequently, the South China is likely to be more vulnerable to devastating typhoons.

The effective elastic thickness( T _e) which depends on the deep lithospheric temperature structure and crustal compositions, represents the lithospheric ability to resist deformation. The Ninetyeast Ridge(NER), one of the longest seamount in the world, has been studied by many researchers over its original and process. However, the complicated tectonic activities cause that it is too difficult to uncover the evolution of the NER. Here we investigated the NER in terms of T _e with convolution method and obtained its spatial variations of T _e. The results show that values vary from 0 to 35 km. T _e is characterized as high value (averaging 20 km) in the north section (8°N~1°N), low value (averaging less than 5 km) in the middle part (1°N~15°S) and high value (averaging 30 km) in the south section (15°S~30°S), which are associated with three stages of volcanic activities of Kerguelen hotspot. In addition, the variations of values reflect the adjustment of relative position between Southeast Indian Ridge and hot spot during the evolution of NER and further prove that the NER is influenced and controlled by the Kerguelen hotspot, Indian plate's drift and Southeast Indian Ridge's jump. Finally, by combining with the evidence of ROYER's plate reconstruction, a model was proposed to show the evolution of Ninetyeast Ridge.

The distribution characteristics of ∑REE in the bottom sediments are influenced by many factors, so they are too difficult to analyze quantitatively. From qualitative analysis of the relationship between ∑REE content and its provenance, hydrodynamics, grain size and mineral distribution in Beibu Gulf, it is revealed that the main ∑REE composition is controlled by terrestrial rock. Both weaker hydrodynamics and the finer grain lead to the higher ∑REE content. Combined with the quantitative analysis of BP neural network which trained by the position of samples, gravel content, sand content, silt content, clay content and clay mineral content, the relative curves of individual impact factor with ∑REE content were achieved. These relative curves reveal the relationship between the ∑REE content and various impact factors, and the results are consistent with those of qualitative analysis. The method can study by itself, determine automatically and calculate quantitatively. It is helpful for identification of the impact related to each factor and ∑REE and to know how it is controlled the ∑REE distribution. So according to the curve variation and actual situation, environmental changes and geological evolution of the region can be inferred. This also provides a useful theoretical guidance for the analysis of the enrichment and dispersion for the rare earth elements.

Development potential assessment of land resource plays foundation for land use planning. Therefore, finding out the land potentiality of economic production capacity is a key proposition of allotting land resource in the background of urbanization and industrialization. In this study, the index system was established based on natural condition, ecological sensitivity, economic development and spatial structure, moreover, fuzzy comprehensive evaluation and analytic network process method were adopted respectively to value each index and weight. This study figured out potential value by map algebra in ArcGIS and divided study area into four potential districts with natural break method. The conclusions show that: (1) low potential district has the area of 237.14 km ², taking the percentage of 17.73%; medium potential district has the area of 323.08 km ², taking the percentage of 24.15%; high potential district has the area of 473.34 km ², taking the percentage of 35.38% and extreme high potential district has the area of 304.27 km ², taking the percentage of 22.74% respectively. (2) According to the analysis of land use types in different land potential districts, transport land and natural reserved land area reach the peak in extreme high potential district and decrease from the extreme high potential district to the low potential district; cropland, rural-urban construction land, other agricultural land and other construction land have the biggest ratio in the high potential district and mostly distribute in the extreme high or the high potential district; garden plot, water surface and water conservancy land are basically distribute in the medium potential district, while tidal flat and woodland distribute in the medium and low potential district.(3) Land development potential in coastal zone of these cities have different characteristics, which are specified as: the potential district in Yuyao county belongs to further-promotion type, the potential district in Cixi county belongs to balance development type and the potential district in Zhenhai belongs to high potential quality type.

Eight uninhabited islands of Sixteen Door are located in the Zhoushan sea area with a high-intensity development. Base on the bathymetric data of 1962, 2002 and 2012, GIS technology was applied to analyze the beach scouring and silting in this region. The results indicate that in the past 40 years from 1962 to 2002, the sediment had been silted up in the study area with the rate of 5.3 cm/a. However, it presents an adjustment from slow silting to rapid scouring in the recent decade from 2002 to 2012, with the annual erosion rate of 52.7 cm/a. According to the analysis, since 2002, the combined effects of the intensive human activities in the study area and its vicinity are the main reason for rapid sediment erosion of the underwater slope.

The coastline information of Bohai Rim in the year of 1980, 1990, 2000 and 2010 was extracted using remote sensing images of Landsat MSS, TM and ETM+ and GIS techniques, and the fractal dimension of the coastline was calculated by box-counting method. The characteristics of spatial-temporal variations of the coastline's length and the driving forces of coastline changes were assessed, and the relationship between the coastal development activities on various scales and fractal dimension changes were also discussed. The results showed that during the research period, the coastline length of the study area increased by 1 074.35 km and the rising intensity increased progressively. The coastline length entered a period of rapid growth after 2000. The most significant change of coastline length was found in Bohai Bay. During the study period, the coastline mainly expanded to the sea. Human development activities were the leading factor for coast change. Before 2000, coastal development was predominantly constituted by reclamation of aquaculture and salt fields; while after 2000, factors causing coastal change tended to become diversified and rates of harbor construction and construction lands increased. The fractal dimension of the overall coastline was increased steadily, indicating that the geometry of the coastline of the study area became more complex. The magnitude and variations of fractal dimension were directly related to material composition and evolution process in the coastal zone. A large numbers of coastal engineering construction of various scales were the leading factor in fractal dimension variation.

The effects of cleaning dredged materials on the growth of two marine microalgae species with different initial cell density: Skeletonema costatum and Heterosigma akashiwo, were investigated by using the measures of experimental ecology. The results show that at the unialgal culture medium of cleaning dredged materials in laboratory, the different initial cell density has apparent effects on the growth of microalgae. At the initial cell density of 0.2×10 ⁴ cells·mL ^-1, the time of entering exponential phase and stationary phase can be extended, and reaching the maximum cell density is higher; at the initial cell density of 0.8×10 ⁴ cells·mL ^-1, the time of entering exponential phase and stationary phase could be shortened, and reaching the maximum cell density is reduced. For the mixed cleaning dredged materials culture medium, the different initial cell density has apparent effects on the relation of interspecific competition between two species of microalgae. There is obvious interspecific competition between S. costatum and H. akashiwo. H. akashiwo has predominance in this competition, and S. costatum suffers from H. Akashiwo inhibition, within the entire experimental period, cell density reduces very significantly and is lower than that in the unialgal culture, while H. akashiwo cell density is not significantly reduced. Among these three different medium concentrations of cleaning dredged materials, the cell density in the highest culture medium concentrations of 1 000 mg·L ^-1 is significantly lower than those in 100 mg·L ^-1 and 500 mg·L ^-1 culture medium, and the cell density is the highest in 100 mg·L ^-1 culture medium. This indicates that the greater of clean dredged materials concentrations, the greater effects on the growth of microalgae, while the lower of clean dredged materials concentrations, the smaller effects on the growth of microalgae.

In this study, acute and sub-acute experiments were conducted to elucidate the toxic effect of cadmium on Portunus trituberculatus. The results show that the median lethal dose of cadmium are 6.55, 4.33 and 3.12 mg/L for 48 h,72 h and 96 h respectively, and the safe concentration of this metal is 0.31 mg/L. As the extension of exposure time, the expressions of HSP70 in hepatopancreas and gill are increased at the beginning, and then decreased significantly under the safe concentration and fishery water quality standard. Compared with control group, the expression of HSP70 in gill is more obvious than that in hepatopancreas. Under the safe concentration, the survival rate of Portunus trituberculatus is not changed obviously, but the excessive expression of HSP70 reflects that the crab is stressed by Cd ²⁺ exposure, so HSP70 indicators can be reflected more sensitive than the median lethal concentration at low concentration of Cd ²⁺ pollution.

A dynamics response model are established using hydrodynamic analysis software OrcaFlex and referring to cable cross section design of Wenchang umbilical cable and operation environmental parameters to simulate the dynamic response of J-tube pull-in installation of the main platform for the umbilical cable under different wave directions. Finally, some instructive notices and mechanical properties during umbilical tie-back were put forward based on related modeling results. The hydrodynamic analytical result shows that the speed of the winch and the change of wave directions have very important effects on the process of umbilical cable pull-in through J-tube; the position where umbilical cable bends badly is where the von mises stress changes obviously as well, but the stress is still less than that permitted by API 2RD, and it can satisfy the request by the engineering safety.

The net-collected phytoplankton community and physicochemical properties of the waters nearby Zhoushan Islands during summer and autumn of 2014 were investigated. A total of 6 phyla, including 92 genera and 184 species were indentified, of which 127 diatom and 30 dinoflagellat species were found in this survey area. The species Skeletonema spp. is dominant in summer, while the dominant species in autumn consists of nine diatom species (i.e., Coscinodiscus jonesianus, Coscinodiscus oculus-iridis, Coscinodiscus argus, Coscinodiscus asteromphalus, Skeletonema spp., Pseudo-nitzschia pungens, Chaetoceros decipiens, Thalassiothrix frauenfeldii and Frustulia interposita). The phytoplankton abundance in summer (1 713.58×10 ⁴ ind/m ³) is higher than that in autumn (1 430.30×10 ⁴ ind/m ³). According to the results of Redundancy Analysis, the temperature, salinity, suspended particulate matter, dissolved inorganic phosphorus and nitrogen are the main environmental factors affected on the phytoplankton community in summer and autumn. Based on the analysis of the integrated historical data, the eutrophication index at the research area has increased clearly since 1996, and the structure of phytoplankton community has also changed significantly. It reflects on the cells abundance increase and the dominant species substitution.

Undisturbed sediment samples were collected from the cage culture zone and nearby of large yellow croaker' farm in Xiangshan Bay in May, Aug. and Nov. of 2013. Total organic nitrogen (TON), total organic carbon (TOC) and total phosphorus (TP) in the sediments were determined. A simulated experiment was conducted to study the sediment oxygen consumption (SOCs) rates and nutrients(NH ⁺ ₄、NO ^- ₂+NO ^- ₃、PO ^3- ₄) fluxes between water column and sediments. TON and TP values of sediment in cage-zone(YZ) are generally significantly higher than those in stations of 50 m away (F1) and 100 m away (F2) ( P<0.05). The sediments release NH ⁺ ₄ to the overlying water where as they takes up NO ^- ₂+NO ^- ₃ and PO ^3- ₄. Benthic fluxes show that intensive seasonal variations and the release of NH ⁺ ₄and PO ^3- ₄reach peak values in August, which response to increased organic input due to the yellow croaker farming. The nutrient concentration in water changes with benthic nutrient fluxes among seasons. The results obtained in this study imply that the ongoing aquaculture activities have led to sediment organic pollution at certain extent and the polluted sediment could affect the benthic nutrient fluxes, which might cause the redistribution of nutrients in water column.

Denmark Strait Ocean Front(DSOF) has higher value in oceanographic research, such as provides a reference to the research on local climate change, fish distribution and the mesoscale eddy around the Denmark Strait. In addition, the research of the DSOF also has a higher application value in the military field. However, there has been lack of systematic research domestically and internationally for the DSOF. In this study, using WOA13 data, the location, spatial intensity distribution and the corresponding seasonal variations of the DOSF were analyzed. The results indicate that: the front axis at the west of 34°W is relatively stable above 150 m, whereas it varies with depths as well as seasons at the east of 34°W. The front intensity distribution is not uniform vertically and horizontally, and in general, the difference between maximum and minimum values are as higher as 3 times in the horizontal direction. The vertical salinity front mainly concentrates above 100 meters, and its intensity is decreasing with depth. The maximum value of temperature front intensity locates below the surface, and when the water depth is below 300 meters, it gradually decreases with the increase of water depth, but in some areas, such as at 27°W and 28°W, the front intensity increases quickly because of the affection of the bottom topography.

An astronomical tide and tsunami coupled numerical model of East China Sea was established by adding tidal boundary conditions into COMCOT tsunami model. Two different tsunami waves, positive leading wave and negative leading wave, were designed according to the dislocation direction of earthquake plates during an undersea earthquake with magnitude of 7.6, which occurred in Ryukyu Trench. The tsunami wave crest and astronomic high tide level occurred at the same time through the modification the phase of tsunami wave. Comparison about the summation of astronomic tide level and tsunami wave level was made between the result of coupling model and linear sum. It demonstrates that in both cases mentioned above, the tsunami wave is in advance no matter for the positive leading wave or negative leading wave. And it's higher for the result of linear sum with respect to tsunami wave height.

Harmful algal blooms(HAB) is one of the most serious marine disasters, which not only reduces fishery production, deteriorates the marine environment, affects coastal tourist industry, but also causes human poison. The satellite remote sensing technology has the characteristics of large-scale, low cost, synchronized and rapid monitoring, therefore it becomes an important method for HAB observation. In this paper, a HAB remote sensing monitoring system is developed based on C++ language. The system can achieve the whole procedure automatically from the satellite remote data acquirement and satellite image process, products generation, and it can automatically identify the HAB region using the spectral reflectance and inherent optical properties derived from remote sensing data. Currently, the national monitoring department has adopted this system for the operational monitoring of HABs in the East China Sea. From April to September 2013,the system had produced 55 red tide remote sensing monitoring products, and had a good application effect. The system was used to extract the location and area of 27 large red tide events which occurred in the East China Sea in recent years. Compared with the results of the field observation, it has a good effect on the recognition of most red tide range, and the discriminating accuracy of red tide is about 80%.

Sediment samples were collected from two sites in the artificial channel salt marsh of the Duliujian River, through continuous sampling along the side wall of artificial dig pits. The chronology was developed using ²¹⁰Pb and ¹³⁷Cs dating methods, and grain size, foraminifera and hydrologic data were used to study the deposition of modern flooding events. The results show that ²¹⁰Pb _exc activities are obviously lower in 3~6 cm and 10~14 cm layers, corresponding to the main peak and minor peak of ¹³⁷Cs. In addition, comparing with the adjacent layers, these two layers show coarse-grained, poorly sorted, low foraminiferal abundance and high foraminiferal brokenness percentage. The results of ²¹⁰Pb dating show that the main peaks of ¹³⁷Cs was 1963, corresponding to the global ¹³⁷Cs fallout well; however, the minor peaks was not 1986, so it was not caused by the accident of the Chernobyl Reactor. The hydrological data show that there were two flood events in 1963 and 1996 in this area. Therefore, it can be concluded that these two special layers of S4 and S5 sites were caused by the flood events. It is indicated that multi indexes can help to reconstruct flood deposition, which also can help to find disasters and climate events in geological periods, and to provide scientific data for disaster prevention and future plan.

The sediment transport patterns were revealed in the Qiongdongnan Basin on the Northern Slope of South China Sea since Late Miocene by the research of the sediment filling patterns since the period of post-rift accelerated subsidence. On the basis of the previous analysis on the potential provenance, combined with the summary and induction of the exploration achievement in the research area, the types of the deep-water sedimentation were identified and the combinations of the deep-water depositional packages which have genetic relationship or the same source were built. In addition, the sediment transport patterns were classified tentatively. The results show that since Late Miocene, there are 4 potential sedimentary sources in the Qiongdongnan Basin: they are Hainan Island' sources, West Yinggehai' sources, Southern uplift' sources and Shenhu uplift' sources, respectively. The sedimentary transport patterns can be divided into three types: they are vertical direction, axial direction and turning direction sedimentary transportation.

Underwater archeology is a new research field in China. In China's coastal waters, there exist a large number of sunken ships along the ancient “Maritime Silk Road”. Recently, underwater archeology has become an active research for the coastal provinces. As such, it is necessary to establish an appropriate survey procedure, using high precision marine geophysical prospecting equipments, e.g., the multibeam sounding system, shallow seismic profiler, side scan sonar, magnetometer, and even ROV systems. In the present contribution, we report the basic procedures adopted for underwater archeological survey over the Chuan Island sea area, Guangdong Province, together with a preliminary description of some new archeological findings. Chuan Island is an important mooring place associated with the ancient “Maritime Silk Road”. Using the multibeam bathymetry system and the side scan sonar, some relict pieces of ancient porcelain in Qing Dynasty, as well as some iron cannons, have been found in the coastal waters of Mud Bay, Datie Bay and Wuzhuzhou Island. The discovery of underwater cultural relic in Chuan Island can promote the activity on the cultural relic investigation along the ancient “Maritime Silk Road”, and the underwater archeology can also gained more attention.

The variation regularity of submarine pipeline's status in Hangzhou Bay was analyzed based on inspecting data over years. The variational reasons of pipeline's exposed and buried status were explored based on the hydrodynamic numerical model and the integrated factors such as the self-burying design of Spoiler, the flow characteristics and the seabed evolution, the human activities in Hangzhou Bay and so on. The results show that above 80% of the pipelines are buried under seabed,while some parts of pipeline are chronically unburied, and the unburied pipelines are mainly located in the deep groove of north shore and the frontier of Andong Beach. The pipeline's scouring is close related to the seabed variational characteristics, the angle between the flow and pipeline, and the self-burying design of Spoiler. In addition, the reclamation project in the south beach of Hangzhou Bay may play an important rule for the pipeline's exposed and buried status.

Based on the Instrument Control Toolbox in Matlab, DGPS signal data can be received via the serial port, so this technique can be used for real-time visualization in ship-mounted ACDP survey. The method was tested at Zhoushan sea area for 28-hour continuous ship-mounted ADCP observation. During the test, the real-time visualization system worked fine, tracks of DGPS, the speed of the vessel, and the direction of the vessel renewed automatically every second, which was satiable the requirement of real-time visualization. The only thing we need to do before the survey is to prepare one background map, the system is stable and is easy to use, and the most important, the system workes stably during the 28-hour observation.

The uncertainties and randomness are the most general issues existing in the risk assessment of heavy metals in sediments, the Monte Carlo technique was introduced for simulating the Hakanson potential ecological risk index, in order to make the risk assessment more scientific and rational. Potential ecological risk assessment modified with the Monte Carlo technique was used to analyze the ecological risk of heavy metals (Cu、Pb、Zn、Cr、Cd、Hg、As) in surface sediments from adjacent waters of Dushan Port. The results show that the pollution degrees of Cu, Pb and Zn are medium contaminated, while others belongs to slight contaminated. The results also illuminate that the probabilities for slight degree and medium degree pollution levels of C_d (the comprehensive pollution index) are 38.32% and 61.68% respectively.As for the ecological risk, all of 7 heavy metals and RI(the potential ecological risk index) are at a slight risk 1evel. The sensitive analyses indicate that Cu、Zn and Cr play leading roles in C_d and RI.

Base on the investigation of Dongshan Bay in May (spring) and August (summer) 2011, the horizontal distribution and its influencing mechanism of dissolved heavy metals (Cu, Pb, Zn, Cd and Cr _(T)) in seawater were analyzed. The results indicated that: (1) The distribution of the heavy metals tended to be a peak source in the southwest sea areas and gradually decreased from west to east, whereas the trend of seasonal variation showed that the heavy metal contents in summer were higher than those in spring except Zn. (2) Since 1980s, changing trend of Cu, Pb and Cd contamination basically showed inverse “U” pattern conforming to environmental Kuznets curves while the content of Zn in seawater increased year after year. (3) The correlations between the dissolved heave metals were analyzed using the mathematic statistic method. It showed that except Cr _(T), among the rest 4 heavy metals, each two had a significant positive correlation in spring, while in summer, only Cu-Cd and Cd-Cr _(T) had a positive correlation. (4) Temperature, salinity, pH, COD, DO, nutrient and the biological effects were the main affecting factors for the variation of dissolved heavy metal contents in seawater.

Based on the macrozoobenthos and environmental materials from 35 stations in Dongtou Islands and adjacent sea area investigated in April 2015, the characteristics of macrozoobenthic community structure and its relationship with environmental factors were analyzed. Results show that a total of 122 species are identified, including 57 species of Polytraeta, 34 species of Crustacea, 19 species of Mollusca, 5 species of Echinodermata and 7 others species. The number of species is about 1~22 at each station, with lower values of species number concentrated in Oujiang River Estuary. The average biomass of macrozoobenthos is 3.35 g/m ², and the average inhabited density is 321 ind/m ². Polytraeta has an advantage on the species compositions, while Mollusca has the more advantages on the biomass and abundance. The average of Shannon-Wiener index( H′) is 1.29, the average of Margalef's species richness index ( d) is 2.45, and the average of Pielou's evenness index ( J′) of species is 0.66. By species similarity cluster analysis and multidimensional scaling ordination analysis, three communities of macrozoobenthos can be divided in Dongtou Islands and adjacent sea area, those are: Heteromastus filiforms-Yoldia similis-Raphidopus ciliatus-Sternaspis scutata (Community Ⅰ), Yoldia similis-Heteromastus filiforms-Aglaophamus dibranchis-Sternaspis scutata (Community Ⅱ), and others (Community Ⅲ ). Canonical correspondence analysis show that the sea water temperature, water salinity, activated phosphate, activated silicate, dissolved inorganic nitrogen, chemical oxygen demand and the total organic carbon in surface sediment are the main environmental factors affecting the macrozoobenthic community. The ABC curves indicate that the macrozoobenthic communities in Dongtou Islands and adjacent sea area have suffered contamination or have disturbed to a certain degree. Compared with historical data, the average biomass and abundance of macrozoobenthos have not obviously changed. The dominant organism of the species compositions are Polytraeta and Crustacea, instead of Polytraeta and Mollusca, and the number of Turritella bacillum in the area has obviously declined.

Green Turtles (Cheloniamydas)were cultured at the water temperature 15, 20, 25 and 30 ℃ for 90 days to study the effects of different water temperature on 17 blood biochemical parameters. Results showed total cholesterol (CHOL) and triglyceride (TG) of cardiac function increased first and then decreased with the increase of water temperature and reached the maximum at 25 ℃, with the values of 3.83±0.30 mmol/L and 0.60±0.08 mmol/L respectively. High density lipoprotein (UHDL) tended to decrease first and then increase. The concentration of creatine kinase decreased with the water temperature increased. Of the liver function, albumin (ALB) and total protein (TP) increased first and then decreased with the temperature rise and reached the maximum at 25 ℃ with the values of 6.47±0.66 g/L and 36.33±1.96 g/L. Other index such as A/G, lactate dehydrogenase (LDH), alkaline phosphatase (ALP), aspertate aminotransferase (AST), alanine aminotransferase (ALT) and total bilirubin (TBIL) showed no significant changes while the water temperature raised ( P>0.05). For the index of renal function, the concentration of blood uric (URIC) and creatinine (CREA) decreased while the water temperature increased and the concentration of urea nitrogen (BUN) had no significant change ( P>0.05). Integrating the effect rule of water temperature on the plasma biochemistry, green turtles cultured at the water temperature 25 ℃ had a low storage material consumption.

Marine observation has been integrated into a united network from different platforms of land, sea, and air, which is the inevitable trend of development. Nevertheless the ability to measure undersea environment in China is extremely weak. After reorganizing some developed countries' policies, major projects, and key technical equipment, and analyzing the current issues confronted, some suggestions of development strategy are put forward in this paper as the reference for managers and researchers.

The wave periods play an important role in marine engineering design, especially for the relationships of ocean wave periods. In this study, one year measured wave period data had been applied to investigate the relationships of different wave periods, such as the spectral peak period, significant wave period, the zero-crossing period, the maximum wave period, and so on. The results of this study were compared with those from some literatures and some correlative standards. The corresponding formulae of different wave periods were put forward. Consequently, our results provide support for the marine engineering design and the study of the relationship between wave periods in the South China Sea.

Under the guidance of Changxing platform margin reef reservoir cognition, combination of the 3D and 2D seismic data, analysis of the sedimentary background, development model & ancient physiognomy were studied comprehensivly. In this study, evolution characteristics of reef in Pengxi-Wusheng depression edge in the middle of Sichuan Basin were analyzed, and three development models of reef in Tailai, Yongxingchang and Yihe depression edge in southeast of Sichuan Basin were put forward. Affected by North Kaijiang-Liangping shelf, Emei taphrogenesis & micro-palaeogeomorphology, the reef deposited dominately in depression edge in Tailai,low-energy bioclast-shoals deposited in Yongxingchang and row reef belt and patch reef developed in Yihe. Analysis of sedimentary pattern of Sichuan Basin during Changxing period, the deposition patterns of reef in Pengxi-Wusheng depression edge and Kaijiang-Liangping shelf margin were similar. The vertical developments of reef were in small scale, but the horizontal area distributed widely in depression edge.

The applicability of cathodic protection criteria was studied by surface observation and electrochemical method while the X80 steel was immersed into seawater solution containing SRB. The results revealed:The corrosion was anode control. The corrosion rate was reduced by increasing the SRB adhesion resistance and the charge transfer resistance on the metal surface in the fifth day. While the metal was protected mainly through changing the charge transfer resistance on the metal surface in the tenth day, and the cathodic polarization potential was more negative, the effect was better. The corrosion products were more and poor adhesion on the metal with no-cathodic polarization, and the corrosion products were less and strong adhesion on the metal surface with cathodic protecting. The cathodic polarization could indeed protect the X80 steel in the presence of SRB. In the fifth day, the protection degree was not up to 85% when the metal was polarized to -850 mV _CSE, and it just could meet the protection requirement while polarized to -950 mV _CSE. And in the tenth day the protection degree was declined, it did not meet the requirement while polarized to -850 mV _CSE and -950 mV _CSE. So it was needed to continue to determine the appropriate cathodic protection potential in the presence of SRB.

Combining the remote sensing images and regular data, the continental shorelines at seven periods in Zhejiang were depicted by using the data during the last 100 years. In those seven periods, continental shoreline types and sea reclamation area were calculated and the results are as follows: (1)The spatial pattern of the sea reclamation and way varied from time to time and the proportion of artificial shoreline has been risen from 48.01% to 67.46% during the last 100 years. (2) The relation between the increment of artificial shoreline and the area of reclamation presented three obvious stages from 1913 to 2014: The first stage is that the largest increment of artificial shoreline between 1913-1970 corresponded to the smallest reclamation area change, which meant that people were priority to individual farming during that time. The second stage is that the reclamation area had began to increase rapidly between 1970-1995 while the artificial shoreline reduced, which represented at this time it was collectivized agricultural era. And the third is that the increment of artificial shoreline is relatively small, however, reclamation area increases enormously, which shows that we are now in the stage of both industry and urban land use. (3)The estuarine coastline has been being translated to the sea and the coastline length has increased or decreased. Since 1913, the main estuary reclamation area is about 1 914.85 km ², and this is around 76.79% in Zhejiang Province.(4)The major changes in the gulf coast was the blockage of the harbor and the total length of shoreline were being continued to reduce in the last 100 years. Since 1913, these three harbors’ reclamation area is 429.32 km ², and it is about 17.22% in Zhejiang Province.

The coastal artificial morphology construction is an important way for coastal countries to exploit the coastal resources. The formation of coastal artificial shoreline changes the pattern of natural shoreline, and influences the succession laws of the natural shoreline. In this study, the mainland coastline in Zhejiang Province in different times was extracted, based on TM remote sensing images in 1990, 2000 and 2010, the structure of mainland coastline and the influence of artificial shoreline construction on the patterns of the coastline in Zhejiang Province were analyzed. The results show that: (1) Affected by the development activities of human, the mainland coastal landscape in Zhejiang Province was characterized by the continued growing of the proportion of the artificial shoreline in recent 20 years. (2) The speed of artificial shoreline construction had significantly differences at different coastal area, especially at the Hangzhou Bay, the Sanmen Bay and the Taizhou Bay. (3) In these 20 years, coastal erosion and retreat occurred at only a small part of mainland coastline in Zhejiang Province. As a whole, it was advancing to the sea obviously. (4) The construction of artificial shoreline shortened the length of natural shoreline and reduced the tortuosity of natural coastline in Zhejiang Province in the process of straightening, but increased the diversity index of the continental coastline.

The Baishamen beach of the Qiongzhou Channel is an important resource for the Haikou city's tourism, but the previous researches presented that it has been in erosion from 1960. The waterlines in 19 Landsat sensing images from 1994 to 2015 were extracted, which were used to calculate the beach slope and analyze the beach erosion and accretion. The results show that the beach was mainly in erosion from 1994 to 2008, the waterline moved 104.71 m to the shore near the high tidal level and 95.49 m to the shore near the low tidal level, but the artificial sand filling in the time around 2000 compensated the erosion. While the beach was mainly in accretion from 2008 to 2015, the waterline moved 34.17 m to the sea near the high tidal level and 25.93 m to the sea near the low tidal level, which may be induced by the Xinbu Island enclose engineering.

Retrieval of offshore bathymetry has important significance in shallow topographic survey, coastal protection and development. In this study, Dongluodao waters in South China Sea was taken as a typical study area, using the SPOT-6 6 m high resolution data, six band ratio model such as blue-green and blue-red were set up respectively based on SPOT-6 multi-spectral data and depth measured values. The results show that green-red band ratio model has the highest accuracy and the R ² value reaches 0.706 4. This has certain reference significance for retrieval of offshore bathymetry in tropical oceans. Comparing with the average relative error of the different depths range based on the above model, the conclusion is that the depth range from 0 to 5 m has the higher average relative error, mainly because the conditions are complex. The depth range from 5 to 10 m has a minimum average relative error of 13.62%. Accretion of the average relative error with the increasing of the depth, while SPM, CDOM and chlorophyll concentration are the main causes of this phenomenon.

Attaching a spoiler on the top of pipeline is a new method to enhance self-burial of pipeline. The pipeline state in Hangzhou Bay with spoiler was investigated in this study in order to understand the mechanism of spoiler. Based on the route survey data combined with the seabed and hydrodynamic characteristics, the effect of spoiler on self-burial of pipeline was discussed. The survey data illustrate that the percentage of buried pipeline increased from 50% in 2005 to over 80% in 2013, and the average buried depth increased to 2.60 m, which shows that this self-burial method is applicable in this region. While some sections of the pipeline where the flow direction is parallel to the route or on strong anti-erosion river bed are still exposed on the seabed due to the ineffectiveness of spoiler.

To automatically sample mesoscale eddies by AUVs, the method to automatically recognize the dynamic features of eddies must be developed. In this study, a method for dynamic feature detection of mesoscale eddies was created based on SLA (Sea Level Anomaly) data. The main innovation is that a criterion to decide the succession relations of eddies was developed. With the succession relations of eddies being confirmed, we can calculate the area changing rate of eddy region, velocity of eddy centroid movement and some other dynamic features. Since the calculation cost of this algorithm is not enormous, it can be used in real time eddy tracking context, such as tracking eddies with AUVs. It is worth noting that SSH(Sea Surface Height) data can also be used in this algorithm. And SLA or SSH data can be acquired from the ocean numerical simulation model, satellite remote sensing or other methods. As long as SLA or SSH data are provided, our algorithm can be easily utilized for dynamic feature detection of mesoscale eddies.

Operational ocean observation instruments (OOOI) lay a solid foundation for operational ocean observation system. Typical OOOI of ocean observing station in China and the U.S. were analyzed comparatively in terms of performance indexes. Then current status and trends of OOOI in the world were described and the prior developing technology of OOOI in China was discussed. The results show that the accuracy of tide gauge is one order of magnitude lower than that in comparing with the U.S., and the accuracy of wave height, period and wave direction are 0.2 m, 0.27 s and 5°~10° lower than those of U.S., respectively. Moreover, operation reliability and stability have also shortcomings. In the world, the ocean observation equipment is becoming more informative, intelligent, professional and modular. Besides, their functions are being perfected through serialization development and the reliability is increasing more and more. Under this trend, high-precision sensor and materials, anti-biological fouling and corrosion protection techniques as well as intelligent electronic circuit, artificial intelligence and automation techniques have the higher priority for developing OOOI in China.

Ultra short baseline positioning system can provide accurate positioning information for underwater equipment. The positioning results of the ultra short baseline positioning system contain a variety of factors, the effective processing of the data is the essential prerequisite for position precision. In this study, the acoustic antenna was calibrated, the accuracy of the positioning data was evaluated, the maritime collecting data were analyzed and the gross points of the raw data were filtered and removed. Finally, the reliable results of underwater positioning thereby can be acquired.

In order to meet the requirements of fast and multi-factors monitoring of the marine environment, a kind of shipborne automatic sampling system (SASS) was developed. SASS has a simple and flexible operation system, and has three control modes: automatic, semi-automatic and manual mode. The hardware of SASS mainly consists of pump, composite cable, electric winch, electric control cabinet and storage tank. With the control of the software, the devices such as winch and collecting pump can open and close automatically, to complete the collection of multi-level seawater samples in same site. Compared with the traditional method, this system can greatly reduce the labor intensity of the experimenters, and improve the precision of sampling depth. After a large number of sea trials in the Bohai Sea and in the East China Sea, SASS has been proved to be stable.

In order to solve the sound source measurement problem in the non-free sound field of reverberation environment, a method of sound field reconstruction was presented. In this method, we took measurement, analysis and reconstruction of the sound source. We chose the anechoic tank and reverberation tank as the experimental environment, the transducer as the simulation object, the hydrophone array as the frontend measurer. By using the single layer hydrophone array, the sound pressure distribution of non-free sound field was measured. Sound wave separation was conducted for the measurement results. The sound pressure distributions before and after the sound wave separation were respectively compared with those in the anechoic tank. At last we calculated the errors of sound field reconstruction. The sound field reconstruction errors were presented when the source frequencies were 5 000 Hz and 7 000 Hz. The results show that this sound wave separation method based on sound pressure measured by the single layer hydrophone array can reconstruct the sound field in reverberation environment accurately.

Based on multi-channel seismic profiles and MODIS images, the form of internal solitary wave (ISW) packets in Dongsha area of the South China Sea was studied. There are two polar waves: elevation and depression wave, and internal solitary waves can be divided into “bell shape”, “flat shape” and “bowl shape” according to the waveforms. The shape of wave trough is associated with amplitude. Influenced by various factors, the solitions will develop into packets within the propagation process. Two typical wave packets are observed at different locations in Dongsha area: rank-ordered ISW packet and more complex ISW packet, and combined with their locations and propagation, they are considered to be two stages of the propagation process from deep sea to shelf. A rank-ordered wave packet is influenced by submarine topography, Dongsha Reef and wave-wave interaction after Dongsha Island, then turns into a more complex wave packet.

Using in situ hydrographic measurements during June 2015 and satellite altimeter data provided by archiving validation and interpretation of satellite oceanographic data(AVISO), the hydrographical features and circulation with influences of cyclonic-anticyclonic eddy-pair in the northern slope of the South China Sea during June 2015 were studied. The results showed that the low-salinity water in northeast-southwest direction was found in the upper 50 m in the northern slope of the South China Sea during June 2015. The minimum surface salinity values were below 32, which indicated the presence of cross-slope transport in the northern slope of the South China Sea. Due to the existence of cyclonic-anticyclonic eddy-pair in the northern slope of the South China Sea during the observation, the cross-slope currents were found in the upper 100 m,of which the maximum velocity was observed in the intersection of two eddies. In addition, the circulation across the continental slope in the Northern South China Sea derived from the moored current measurements, presented two-layer structure: offshore flow in the upper 100 m and onshore flow beneath 100 m.

The vertical distribution of tidal ellipse parameters (amplitude of the major axis, ellipticity, direction and phase) of the dominant M ₂ tidal current in Sanggou Bay are analyzed based on in-situ observed current profile data during kelp-free and kelp-mature periods. The results indicate that the suspended kelp culture has a remarkable effect on vertical structure of tidal current. The parameters of M ₂ tidal ellipse vary little in the vertical direction during kelp-free period. In contrast, due to the impact of the suspended kelp, the M ₂ tidal ellipse parameters show a significant vertical variation during kelp-mature period. Specifically, moving away from the middle layer towards both surface and bottom boundary layers, the maximum velocity decreases rapidly, the ellipticity increases, the direction of the maximum velocity veers clockwise and the appearing time of maximum velocity becomes earlier. The observed data also indicate that at the middle entrance of Sanggou Bay, the direction of the maximum velocity turns from the north-south direction during the kelp-free period to the northwest-southeast direction during the kelp mature period, which was found to be caused by the relevant change of sea level gradient.