This study suggests that the sea surface temperature (SST) in the South China Sea (SCS) has different temporal and spatial characteristics in response to the eastern Pacific (EP) El Niño and central Pacific (CP) El Niño. Temporal features are consistent with previous research: the warm SST anomalies located in the SCS during winter of the developing year and summer of the decaying year of El Niño. As for spatial features, the first significant warming peak is confined to the west of 115°E for EP El Niño events, then the warm SST anomaly center propagate to the eastern SCS, and the second warming peak is located to the east of 110°E. But the double warming peaks are limited to the west of 115°E for CP El Niño events. Different wind anomaly fields during the summer of the decaying year of the two types of El Niño led to different locations of the warm SST anomalies in the SCS. Further physical mechanism analysis show that the second significant warming of the SCS SST during the EP El Niño is associated with the India Ocean basin mode, while the second warming during the CP El Niño is under the influence of the CP El Niño.

By regarding the moderate resolution imaging spectroradiometer (MODIS) remote sensing data as data sources and the southwest coastal waters of Hainan Island as the study area, the improved spilt-window algorithm is used to inverse the SST of the study area from 2005 to 2014. To verify the retrieval accuracy of the SST, we calculate the correlation coefficient between the inversion and measured results using the measured values of 12 observation points; the coefficient is 0.9. Based on the inversion results of SST, the data of four seasons in a year and a decade are analyzed to show the spatial and temporal variations of SST distribution, respectively. Results show that using the MODIS multi-channel improved spilt-window algorithm we can inverse Hainan Island offshore SST accurately. The spatial and temporal variations of SST distribution thus obtained can provide important reference values for marine fishery, change of marine environment and meteorological monitoring.

Utilizing the vertical profiles of temperature and salinity data obtained by Argo floats and multi-source satellite remote sensing data, including sea surface temperature (SST) and sea surface wind fields, combined with the National Centers for Environmental Prediction (NCEP) Ⅱ reanalysis data, we analyzed changes of mixed layer depth (MLD) in the northeastern South China Sea (SCS) in responses to tropical cyclones Kalmaegi (typhoon) and Fung-Wong (tropical storm), which passed the SCS in succession in mid and late September 2014. The results indicate that the maximum net heat flux (upward into the air) increased from 170 to 400 W·m^-2 at the air-sea interface, caused the maximum SST cooling of 3℃ by the “wind pump” effect after Kalmaegi and Fung-Wong passed through. The “cold wake” induced by Kalmaegi lasted for more than 10 days thanks to the following tropical storm Fung-Wong, indicating the effect of superposition in SST cooling. MLD was deepened from 23 to 50 m in the “cold wake” one day after Kalmaegi passed by. MLD was deepened from 31 to 91 m eight hours after Fung-Wong passed by, due to the coastal upwelling induced by offshore Ekman transport driven by wind stress at the southwestern of Taiwan Island. After the tropical cyclones passed by, salinity profile in the mixed layer showed uniformity later than temperature profile, and recovered earlier than temperature profile, revealing the time lag in mixed layer responses. For the spatial variation response to the two tropical cyclones, the changes of SST and MLD were larger on the right-hand side of the tropical cyclones (along the moving directions of tropical cyclones) than on the left-hand side. The uneven deepening even shallowing in MLD in the cold wake may reveal that different depths of deep cold water uplifted by the vertical current switch between upwelling and downwelling in the Ekman layer due to the change of Ekman pumping velocity.

Based on the data of drilling, logging, seismic, geology and basin modeling, we analyzed the characteristics of geothermal, source rock maturation, hydrocarbon expulsion, and accumulation coefficient by using the analogy and genetic methods. Then, prediction of petroleum resources potential in Baiyun depression is carried out. The results show that the Baiyun Depression presents high geothermal gradient, ranging from 34 to 67℃·km^-1 and with an average of 40℃·km^-1, which is favorable for organic matter maturation and hydrocarbon generation. Each source rock has been in the stage of mature or post mature, and the source rock maturation increases from the top formation of Zhuhai to the bottom formation of Wenchang; the area of post mature is 53.7% in the bottom formation of Wenchang. The strength of gas expulsion is bigger than the strength of oil expulsion, and the upper formation of Enping is the major formation of hydrocarbon expulsion. The hydrocarbon expulsion of three source rocks is 1143×10⁸ m³, and prediction of petroleum resources potential in the Baiyun Depression is 25.2×10⁸ m³ combining the accumulation coefficients of oil and gas.

The development of plasma seismic source with large energy output of 50 kJ for gas hydrate exploration in China was introduced in this paper. The structure of the source was compactly designed, and devices were integrated in a mobile laboratory in containers for convenient transport and operation. The field test results showed that the maximum penetration depth of strata of the source was over 1000 m. Compared with the traditional source, the plasma seismic source had higher stratigraphic resolution and improved the reliability of geophysical recognition of gas hydrate. The successful development of the 50 kJ plasma seismic source system broke the international monopoly by whom, and has great significance for China's marine engineering, marine science research and national defense.

The species composition, abundance, biomass and characteristics of macrobenthic fauna in Daya Bay were studied and the main factors that influence the distribution of benthic macrofauna were discussed, based on samples obtained from 32 stations in August 2013. A total of 153 macrobenthic species were identified, including 81 species of polychaete, 37 species of mollusk, 25 species of crustacean, 6 species of echinoderm and 4 species of others. Polychaetes represented the most dominant group and accounted for 52.94% of the total species. The macrobenthos was dominated by Listriolobus brevirostri and Paphia undulata. The average total density and average total biomass of the macrobenthos were 410 ind·m^-2 and 84.83 g·m^-2, respectively. Cluster analysis showed that the macrobenthic community could be divided into five groups with notable differences. Person correlation analysis was conducted between community characteristic indices and sediment factors, which showed that petroleum hydrocarbon in sediment in Daya Bay was main environmental factor affecting the benthic community structure in summer. BIOENV analysis showed that the benthic species abundance was closely related to organic matters and heavy metals such as lead, copper and cadmium.

COMMDs are recently discovered in many multicellular organisms. They are involved in numerous aspects of biological processes, such as the regulation of copper homeostasis, the transport of sodium ions, the activity of the transcription factors NF-κB, and hypoxia-inducible factor (HIF-1). To investigate the role of Commd1 in response to salt stress, we first cloned Commd1 cDNA using Rapid Amplification of the cDNA Ends (RACE) technique in mollusks, Crassostrea hongkongensis (designed ChCommd1). The full-length cDNA is 841 bp containing a 5′-untranslated region (UTR) in 18 bp, a 3′-UTR in 262 bp with a poly (A) tail, and an open reading frame (ORF) in 564 bp; the ORF encodes a 187 amino-acid polypeptide with a predicted molecular mass of 21.79 kDa and an isoelectric point of 5.21. Homologous comparison and phylogenetic analysis revealed that the 187-aa-long ChCOMMD1 protein shares high sequence identity with its homologs from other species and belongs to the molluscan COMMD1 family. Quantitative real-time PCR analysis showed that ChCommd1 mRNA is broadly expressed in various tissues and during different stages of the oyster’s embryonic and larval development. Upon exposure to two stressors (high and low salinity), the expression level of ChCommd1 mRNA increased significantly. Taken together, our results indicated that ChCommd1 can function in the embryonic development and osmotic regulation, providing an important reference for further investigations on the functions of Commd1 in the euryhaline mollusks.

Montipora is the second species-rich scleractinian genus that is widely distributed in the Indo-Pacific Ocean. Montipora digitata and Montipora fragilis, two species of branching Montipora, from the South China Sea were selected in this study, and its skeletal microstructures and calcification processes were observed and analyzed using Scanning Electron Microscopy (SEM) combined with Energy Dispersive Spectrometer (EDS). The results showed that the two species of Montipora skeletal basic elements were substantially the same (including calice, septum, theca, dissepiment, etc.), but there were many differences in details. Coenosteum surface of M. digitata was glabrous and recticular formation with shorter spines (about 40 μm) and each calices (about 1 mm) were separated by big interval. The septa of the first cycle was poorly developed except that the shape of its direct septum was sheet. In addition, teeth along the margin of septa developed well and had flat shape. The coenosteum surface of M. fragilis was tuberculate and recticular formation with many small spines (about 100 μm) and irregular nodular ridge between the calices. Compared with M. digitata, the first-cycle septa of M. fragilis had degenerated teeth. Main ingredients of the two kinds of coral skeletons were aragonite crystals, with most being tufted-crystals and a few being pebble-crystals. EDS analysis showed that the components of calcium carbonate from the skeleton were not directly generated, but formed in the following four processes: 1) the calcium was concentrated to develop calcium point; 2) calcium combined with carbon and oxygen, and the content of carbon was higher than that of oxygen; 3) aragonite crystals tended to look regular, and the content of carbon decreased and that of oxygen increased; and 4) a lot of aragonite crystals gathered into sclerodermite in orderly arrangement to form mature skeleton.

Sexual reproduction of Platygyra carnosus was observed preliminarily under the condition of artificial culture. Eggs and sperms of Platygyra carnosus were collected when they were spawned. The morphological characteristics in early development of Platygyra carnosus during different periods were recorded and described. The results showed that the corals were hermaphrodites, in vitro fertilization, and began spawning on the ninth day after the full moon,, then the spawning quantity of corals increased to the maximum on the 11th day after the full moon. The eggs of Platygyra carnosus were spherical in shape and pink in color. The early development process underwent five phases and 17 stages under the conditions of 27±0.5℃. The fertilized eggs developed into planula in 48 h and the larvae began to settle after 96 h. The sexual reproduction and early development of Platygyra carnosus were reported for the first time in China.

Planktonic ciliates are widespread micro-zooplankton in marine ecosystem and are considered as a key link between microbial loop and classic food chain as they play important roles in transfer processes of material and energy in the ecosystem. To better understand the distribution and ecological function of planktonic ciliates in tropical ecosystem, ciliate samples were collected in the coastal waters of Sanya Bay at 6:00, 12:00, 18:00 and 24:00, respectively, in April 2014. Species diversity and community structure of ciliate from different times were analyzed by molecular detection based on species-specific primers. The results were as follows. 1) Planktonic ciliate showed high diversity, with about 79 operational taxonomic units (OTUs) detected. 2) Significant variation of species diversity was uncovered at different times during a day, showing a decrease trend in day time but increase trend at night time and the order was morning [48 OUTs(operational taxonomic units)] > night (37 OTUs) > evening (32 OTUs) >midday (29 OTUs). The reason may be that different ciliate populations have different distribution modes.

Based on in situ physical and biological data collected in different seasons between 2014 and 2015, we described systematically the spatial-seasonal characteristics of chlorophyll a (Chl a) and primary production (PP) in the Pearl River Estuary (PRE) and their relationships with environmental factors. The results indicated that the average values of Chl a concentration and PP in the PRE were 3.77 mg·m^-3 and 27.86 mg C·m^-3·h^-1, respectively. Both were higher in spring than in the other seasons, and the lowest were in winter. The spatial distribution of phytoplankton was mainly driven by the Pearl River discharge and the phytoplankton bloom was related to the location of salinity front. Due to nutrients limitation in the lower parts of the estuary, the bloom occurred in the upper parts when river discharge was relatively small. In contrast, although the nutrients were favorable for phytoplankton growth during wet season with large river discharge, the bloom was absent in the waters near the outlets likely associated with light limitation and dilution. The distribution of primary production in the PRE was well related to Chl a. The results also suggested that phosphorus was the potential limiting factor for phytoplankton growth in the lower parts of the PRE during wet season and low temperature was another reason for low primary production besides light in winter. Compared with previous results, the primary production was in the intermediate level in PRE during 2014~2015. The mean value of carbon assimilation index (AI) in the PRE was 7.51mg C·(mg Chl a)^-1·h^-1 and the carbon fixation level was 261.52 g C·m^-2·y^-1.

This paper dealt with one new record species of family Turridae collected from the South China Sea, Crassispira cerithina (Anton, 1838). Detailed morphological description on the shell was presented. The taxonomic status and the major identification characteristics of this species were discussed. All specimens were deposited in the Marine Biodiversity Collections of the South China Sea, Chinese Academy of Sciences.

Mangroves are widely distributed in the coastal areas of South China, which can effectively reduce the damage by waves to the beach; therefore, it is significant to study the effect of the changes on the beach profile under the influence of regular waves. Based on the wave flume experiment, the PVC tubes are generally chosen to simulate mangroves, and cohesionless sand is selected to generate the beach whose combination slope is 1/10~1/20. The results of the experiment show that when there are mangroves, it has a large influence on the beach slope change under the action of regular waves; and the steepness of regular waves, as well as the distribution density and the arrangement of mangroves, are analyzed. Based on the experimental data, the relationships among the beach erosion scale, deposition scale, the maximum scour depth, the maximum deposition height, and the steepness of regular waves, the distribution density, the arrangement of the mangroves are established, whose relationship is an exponential function. The function reveals the relationship between the variation of beach profile and the hydrodynamic characteristics of regular waves, mangroves, the sediment particles, and the beach slope. With the introduction of the comprehensive coefficient of the plants, the characteristic value of beach erosion and deposition under a given regular wave is predicted, which provides a scientific basis for the construction of coastal protection engineering.

The residual antibiotics have caused public concerns with the rapid development of aquaculture, due to their adverse effects on aquatic ecosystems and human health. A method named solid-phase extraction-rapid resolution liquid chromatography-tandem mass spectrometry (SPE-RRLC-MS/MS) was used to determine the occurrence and bioaccumulation of 35 antibiotics (14 sulfonamides, 10 fluoroquinolones, 6 macrolides, 2 tetracyclines and 3 others) in environmental matrix and different tissues of fish in the Nansha aquaculture area of Guangzhou. Twelve antibiotics were detected in water, suspended particulates, sediments and feeds, with maximum concentrations of 60.76 µg·L^-1 (Erythromycin-H₂O), 1691 ng·g^-1 (Monensin), 2.41 ng·g^-1 (Enrofloxacin) and 74.96 ng·g^-1 (Enrofloxacin), respectively. Eleven antibiotics were detected in fish plasma, livers and muscle, with maximum concentrations of 33.52 µg·L^-1 (Erythromycin-H₂O), 199 ng·g^-1 (Norfloxacin) and 22.30 ng·g^-1 (Norfloxacin), respectively. The values of bioaccumulation factors (BAFs) for the detected antibiotics in fish plasma, livers, and muscle were in the ranges of 147~336, 7~8891 and 8~16, respectively, indicating a different bioaccumulation capacity for different tissues. Human health risk assessment based on potential fish consumption indicated that residues of antibiotics in these aquatic products do not pose risks to consumers’ health. The current study is of great significance in ensuring the safety of aquatic products in Guangzhou, promoting the sustainable development of aquaculture and improving the regulation on residual antibiotics for environmental protection agencies.

Based on the All India Rainfall data, NCEP/NCAR reanalysis data and HadISST data, we demonstrated a delayed effect of the El Nino-Southern Oscillation (ENSO) and Indian Ocean Basin (IOB) mode on Indian summer monsoon rainfall (ISMR). The results showed that decreased Indian rainfall in the early summer (Jun-Jul) and increased rainfall in the late summer (Aug-Sep) are influenced by the anti-symmetric mode and the second warming in the northern Indian Ocean (NIO). The responses of ISMR to El Niño are distinct between the developing and decaying years. In the developing year of El Niño, the ISMR decreases due to the change of Walker circulation in the tropical ocean. In the decaying year, the IOB mode decreases (increases) the ISMR in early (late) boreal summer. The anti-symmetric pattern of atmospheric anomalies with northeasterly (northwesterly) wind anomalies north (south) of the equator happens in spring. The northeasterly anomalies weaken the Indian Summer Monsoon and force the second anomalous sea surface temperature (SST) peak in the NIO by reducing wind speed and surface evaporation. The southwest monsoon brings more moisture (Q°), which is produced by the warm NIO SST to the India subcontinent, leading to increased monsoon rainfall in the late summer.

Although a large amount of aluminum enters the ocean through atmospheric dust deposition every year, the effect of aluminum on marine phytoplankton is seldom examined. Few studies focused on the effects of aluminum on marine nitrogen-fixing cyanobacteria, which play important roles in nitrogen and carbon cycling in the ocean. In this study, a unicellular marine nitrogen-fixing cyanobacterium Crocosphaera watsonii grew in Aquil medium without silicate and nitrogen by semi-continuous cultures. We studied the effect of aluminum (0, 0.2, 2 and 20 μmol•L^-1) on the growth rate and nitrogen fixation rate of Crocosphaera watsonii by using flow cytometry and ¹⁵N isotope tracer method. Results showed that aluminum inhibited the growth and nitrogen fixation of Crocosphaera watsonii. Results also showed that cell size, cellular pigments and photochemical efficiency of photosystem II (F_v/F_m) of Crocosphaera watsonii treated with aluminum were significantly decreased. These results demonstrate that aluminum has an inhibitory effect on the growth and nitrogen fixation of Crocosphaera watsonii under the condition of sufficient phosphate and trace nutrients.

QTL411871 was identified in the verifying population of Pinctada fucata, and two genotype matings♀AT×♂AT(Group No.30 ) and ♀TT×♂AT(Group No.31) were established to analyze genotype selection effect of QTL. The results showed that QTL411871 was significantly associated with muscle mass in the verifying population (P<0.05), and AT was the superior genotype. QTL411871 was not significantly associated with growth traits in Groups No. 30 and No. 31 (P>0.05); the genetic effect of AT genotype was small, but it was still the genotype with the maximal average of growth traits. QTL423886 was significantly associated with shell height, shell length and total weight in Group No. 30 (P<0.05), and the oysters with genotype AG were bigger than those with the genotype GG in terms of shell height, shell length and total weight, but it was not significantly associated with growth traits in Group No.31 (P>0.05). Diplotypes were constructed based on the two QTLs, and association analyses revealed that C₁ (ATAG) in Group No.30 and D₁ (ATAA) in Group No.31 might be the most advantageous diplotypes for growth traits. These results are useful for developing molecular marker assisted breeding of Pinctada fucata.

The Xijiang Fault is an important fault of the Pearl River Delta. To learn the quaternary activity of the Xijiang Fault furtherly, geological mapping in 1:50000 scale, age dating, shallow seismic reflection and drilling verification were performed. The results show that the quaternary geomorphology and fracture coupled. The character of historical seismic reflection shows the fault is still active. Field survey and shallow seismic reflection show that the fault didn’t cut quaternary strata. Chronology shows that the activity strength was relatively strong before the Late Pleistocene, and became weak afterward. Tectonic analysis of Modaomen indicates that there is a sudden change in the sedimentation rate at both sides of the fault, but activity strength is weaker. In short, the Xijiang Fault is still active, but its strength is weak.

In this study, we measured compressive strength in coral samples from Weizhou Island, northern South China Sea, and the Meiji Reef, the Nansha Islands, southern South China Sea, using uniaxial compressive strength experiments. Differences in coral skeletal structure were revealed using these data, coral reef geological and ecological methods, and the engineering mechanics. The results showed that the uniaxial compressive strength of Meiji corals is approximately three times higher than that of Weizhou corals, indicating that Weizhou corals’ carrying capacity is relatively low. The mechanical properties of Nansha corals showed a character of elastic curve, with a short stage of yield and good ductility. On the contrary, the compressive strength of Weizhou corals has an irregular changing elastic curve character, with multiple compression processes. Based on the observations on the broken samples after compressive experiments, Weizhou samples were not broken on the growth direction of the axis, but in the area of small holes and low density. Increased bioerosion caused changes in the structure of Weizhou coral skeletons, and subsequently poor compressive strength, low bearing capacity, and chaotic mechanical properties. This work demonstrates the effect of water pollution on coral skeletal structure. We suggest that priority should be given to seawater quality protection and control before reef project and coral ecological restoration.

Mangrove swamp plays an important role in the maintenance of ecological balance in tropical-subtropical coastal regions, as well as in the global carbon cycle. The grain size characteristic and sedimentary rate of two mangrove swamps were studied. The grain size and proportion of storm deposit were determined, and the factors that influenced storm sediment inputting flux were analyzed. The variation of mangrove swamp accretion rate in response to climate change was also studied. The main conclusions are as follows. 1) The inputted sediments were silt and clay in normal weather condition during tidal process, while the sand component in mangrove swamp sediment was likely inputted by storms. In mangrove swamp sediment, the proportion of storm deposit was 56% for mangrove swamp of the Nanliujiang River estuary and 73% for Daguansha mangrove swamp. 2) The sedimentation rate of mangrove swamp was positive related to typhoon landfall frequency rather than rain fall. 3) The storm energy was higher in Daguansha mangrove swamp than in the Nanliujiang River estuary, likely attributing to its open coastline shape with narrow width in tidal zone and mangrove belt, which may deduce more storm deposit inputted and higher sedimentary rate.

To understand the elemental occurrence phases and the origin of ferromanganese nodules in the northern South China Sea, selective leaching techniques have been utilized to study the geochemical phases (viz. carbonate, Fe-Mn oxide and residual) of ferromanganese nodules on the upper continental slope and the lower continental slope, as well as in the deep-sea basin. According to the Fe-Mn-(Cu+Co+Ni) diagram, Fe-Mn nodules around the Dongsha Islands are associated with hydrocarbon seeps. Nodules on the lower continental slope and in the deep-sea basin have a similar formation mechanism, and are both hydrogenous in origin. K, Ca, Na, Mg, and Sr are mainly enriched in the carbonate phase; Fe, Mn, Ni, Cu, Zn, and Pb are mainly concentrated in the Fe-Mn oxide phase; Al, Ti and Mo are mainly concentrated in the residual phase. The variation of elemental occurrence phases is influenced by multiple factors. The strength of biological productivity and the dilution of calcareous bioclast material can result in change of carbonate phase of Fe-Mn nodules. On the lower continental slope and in the deep-sea basin, REEs and yttrium are mainly associated with the Fe-Mn oxide phase. However, the carbonate and residual phases of hydrogenous oxides have extremely low REE content. The REE origins in carbonate phases of Fe-Mn nodules from different areas are basically similar. The Fe-Mn nodules in the slope area and deep-sea basin have identical residual phase distribution of REEs and yttrium except for the upper slope area. It is probably influenced by residual sources and redox environment of the Fe-Mn nodules. This study discusses the elemental chemical phases in Fe-Mn nodules in the northern South China Sea and provides important basic data for the resources evaluation in this area in the future.

A two-dimensional ocean bottom seismometer (OBS) survey line (OBS2015-2) was carried out in 2015, which was an E-W trending and located in the front of the Manila Trench subduction zone. In this study, we take two OBS stations (OBS04 and OBS08) as examples to introduce the data processing flow for this short-period OBS type of data. The process includes data format transforming from original RAW data to SAC format and then to SEGY format; and it contains shot relocation and OBS position relocation. The preliminary results of data processing demonstrate that the OBS data are of high quality in this experiment. The seismic phases, such as PsP, Pg, PmP, etc. are very clear along the OBSs’ seismic record sections. They are further identified by the forward modeling using the Rayinvr software. Especially, the reflective seismic phases from the Moho interface are abundant and obvious in the incoming plate along the Manila Trench subduction zone, which will provide good constraints for the crustal bottom of the incoming plate.

It is of great significance to fully exploit the oceanic application potential of the GaoFen-1 data, which is the first domestic high-resolution satellite of Earth observation in China. In this study, a GaoFen-1 multi-spectral image is used to retrieve the island shallow water depth of Jinqing Island in Xisha sea area by adopting the dual-band linear model and log-ratio model, after serials of image processing including image geometric correction, atmospheric correction and sun-glint correction. The accuracy of the two models is evaluated by using actual water depth data. Meanwhile, possible influence factors of retrieval accuracy of island shallow water depth from satellite data are discussed. It is shown that the result from the dual-linear model is obviously better than that from the log-ratio model, and the dual-band linear model is more suitable for the retrieving shallow water depth of Jinqing Island. For water depth less than 20 m, the overall root mean square (RMS) error is 1.8 m with RMS error of 1.14 m within 5 m, which reaches the level of accuracy of water depth inversion by satellite remote sensing.

A method was proposed to solve the fusion problem of full polarimetric synthetic aperture radar (SAR) and moderate-resolution optical remote sensing image, based on principal components analysis (PCA) and HSV transform, where HSV stands for hue, saturation, and value. First, the four bands of full polarization SAR went through principal component analysis, and the first principal component was extracted. Second, moderate-resolution optical image was transformed into the HSV space, and the V component was replaced by the first principal component. Finally, the desired image was obtained by using inverse IHS transform. The experiment was performed using Radarsat-2 full polarimetric SAR and TM/ETM+ moderate-resolution optical image. A comparison of the proposed method with the fusion of single polarimetric SAR and optical image based on a traditional method (PCA transform, HSV transform, or wavelet transform) showed that the proposed method made effective use of the texture information of full polarimetric SAR and improved the capability of image interpretation.

Quality control (QC) is a key for microwave sounding radiance data assimilation in numerical weather prediction (NWP) models. In this study, a new approach of QC for Advanced Microwave Sounding Unit-A (AMSU-A) radiance was developed by introducing brightness temperature gradient of view point. In this approach, the data were considered to be contaminated by precipitation if their gradients were anomalously large, and would be discarded. Two typhoon cases, Kalmaegi in 2008 and Kompasu in 2010, were simulated by WRF (Weather Research and Forecasting) model to see the impacts of the new QC method on AMSU-A radiance. In the new QC cases, as the contaminated data removed from the three-dimensional variational assimilation (3DVar), the tracks of both typhoons were much closer to the observations due to the increments of initial geopotential height and wind fields. In addition, the typhoons’ intensities were much closer to the observations with more reasonable temperature field for the warm structure of typhoon core development. In the original cases, with much more contaminated AMSU-A radiance in WRF, both typhoons’ tracks and intensities were much worse simulated. An improvement ratio to simulated track error was 12, that is an improvement to 540 km compared to the track without AMSU-A radiance assimilated, in the Kalmaegi case. And the ratio was 13 with 118 km improvement to simulated track in the Kompasu case.

Land reclamation is an important way to use the ocean. But frequent human activities have a far-reaching influence on local marine ecosystem. Using the Qi’ao Island sea area as the study area, we surveyed the environmental factors and the changes of the biological community before and after reclamation. From the trend of the changes in the environment and the changes of phytoplankton, zooplankton, and the diversity and species of fish before and after reclamation, we investigated the influence on local marine ecosystems caused by the reclamation projects around the southern Qi’ao Island from 2010 to 2014. The results showed that the reclamation has had different degree of negative impact in terms of heavy metal pollution and eutrophication, and reduced the stability of local biological community. The community species has also decreased after the reclamation.

Since the Late Mesozoic, the plate evolution in the Pacific domain has influenced the tectonic evolution, magmatism and mineralization of the East Asia margin. Improving our knowledge about the Pacific evolution will benefit our understanding of the tectonic evolution of East Asia continental margin. In this paper, we summarize updated research results on the tectonic evolution of the paleo and present Pacific Ocean from three aspects, the distinction between Pacific and Tethys tectonic domains, important tectonic events during Pacific evolution and the ridge subduction around the Pacific. Possible effects of Pacific domain on the evolution of East Asia continental margin are probed. Our aim is to call on more intensified research on Asia continent and Pacific Ocean, and to provide an easy reference for such research.

Marine cabled seafloor observatories have been constructed and developed quickly recently in the world. Based on scientific requirements and objectives, many countries, including Canada, United States of America, Japan, and European countries, have built up cabled seafloor observatories, respectively. Infrastructures and progresses of different cabled seafloor observatories constructed by different countries were outlined and reviewed in this paper. Since 1978, 10 cabled seafloor observatories in Japan have been successfully built using coaxial cables at the beginning and using fiber-optical cables recently. One near-coast seafloor observatory and one regional-scale observatory were built in Canada. Two seafloor observatories were organized and managed by the Ocean Network Canada (ONC), and both are maintained by the University of Victoria. In 2012, the longest regional cabled seafloor observatory in the world (nearly 900 km long) was deployed in the USA. Cabled seafloor observatories in Europe have been planned to cover different ocean regions. In China, cabled seafloor observatories were built in Taiwan (MACHO) and in the East China Sea (Xiaoqushan). Based on these cabled seafloor observatories in the world, we proposed important technologies required by ocean networks, and suggested that remotely operated vehicles play key roles when cabled seafloor observatories are reconstructed. Finally, the development and challenge of cabled seafloor observatories are discussed, including some key notes and questions that should be considered by decision-makers when a new cabled seafloor observatory will be prepared and developed in China.

This paper is the first part of our studies on the tidal dynamics in Daya Bay (DYB), China. It illustrates the recent field work results. We establish a three-dimensional, fine resolution, unstructured grid, coastal ocean model to reproduce the tides in DYB. The combination of observation and simulation in this paper gives a better description on the tidal dynamic system in DYB than previous studies. Shallow water tides, especially the sexta-diurnal tides increase fast in DYB, which become the most notable characteristic of DYB tidal dynamic system. In the Fanhe Harbour at the northeastern DYB, the amplitude of M₆ tide reaches the maximum, at the same order as M₄ and S₂ tides. In the open sea outside DYB, the tidal current is dominated by a rotating shape; but once the current enters the bay, it turns to rectilinear quickly. In the main tidal channels, the magnitude of M₆ tidal current is even larger than those of M₄ and K₁ tides. The distribution of tidal energy flux indicates larger tidal energy dissipation for higher frequency tides. In DYB, both the tidal energy dissipation rate and the net tidal energy dissipated in a semi-diurnal period are much larger by M₆ tide than by M₄, M₂ and K₁ tides. The observed Euler residual currents show different spring-neap variation in magnitude inside DYB, and reveal the influence of the coastal current outside the bay. The numerical simulation shows a multi-vortex of residual current, and indicates poor water exchange in the bay.

This paper is the second part of our studies on tidal dynamics in Daya Bay (DYB), China. It illustrates the generation mechanism of double high waters and double-peak flood-current flows. Double high waters resulted from a subtle interaction between a semi-diurnal tide (M₂) and higher harmonics (M₄ and M₆) in DYB. Based on previous studies, the conditions to produce double high waters and double-peak flood-current flows were found in this study by using an analytical method. The double high waters could be generated by combinations of M₂/M₆ tides (limited in the Fanhe Harbor) or M₂/M₄/M₆ tides; however, the combination of M₂/M₄ tides failed to produce this unique phenomenon in DYB. Besides, the water falling range between two high waters generated by the combination of M₂/M₄/M₆ tides was larger than that of M₂/M₆ tides, both in extension and in magnitude. The combinations of M₂/M₄, M₂/M₆ and M₂/M₄/M₆ were all able to produce double-peak flood-current flows, but the magnitude of M₂/M₄/M₆ triplet was larger than the other two pairs in DYB.

Deep-sea microbial esterase BSE00077 can efficiently resolve (±)-1-phenylethyl acetate and generate (R)-1- phenylethanol. The optimal working conditions for the enzymatic resolution of (±)-1-phenylethyl acetate by marine microbial esterase BSE00077 were found to be: 50mmol/L (±)-1-phenylethyl acetate, 10% n-heptane (v/v), pH 7.0, 30°C for 2h. After process optimization, desired optically pure product (R)-1-phenylethanol was obtained with an enantiomeric excess of over 99% and a conversion of over 30%. Esterase BSE00077 can also enzymatically resolve some other racemic 1-phenylethyl esters with different chain lengths. We found that the chain lengths could greatly affect the enantiomeric excess of desired product. Esterase BSE00077 is a novel marine microbial esterase with great potential in the asymmetric synthesis of (R)-1-phenylethanol as well as of other chiral chemicals in industry.

The community structure and diversity of macrobenthos under different anthropogenic disturbances and different vegetation types in Mangzhou wetland of HengqinIsland, Zhuhai were investigated. A total harvest of macrobenthos were 66 species, including 20 species of mollusks, 15 species of crustaceans, 14 species of fish, nine species of annelids and eight other species (mainly insect larvae). The results showed that the major macrobenthos life form was of infaunal and adhering type while caving type (crabs) was the minor life form. Ddominance and dominant species were concentrated in a few r-strategists, such as Tarebia granifera, Cipangopaludina ussuriensis, Discapseudes mackie, Exopalaemon carinicauda and Ilyrplax deschampsi. The maximum habitat density and biomass were molluscs in each study area. Macrobenthos types mainly included smaller and shorter life cycle of r-strategist; and there was a lack of large and longer life k-strategist, which was the common feature of the early successional communities. Shannon-Wiener diversity index (H'), Pielou evenness index (J'), Margalef richness index (d), and Simpson index (C) were not significant (P>0.05) in different seasons and different areas. In three regions, the highest concentration (C = 0.4896), the lowest species diversity (H' = 1.288), the highest species richness (d = 4.301), and the lowest evenness (J' = 0.3583) were found in the river natural forests (Zone B). The species diversity, richness and evenness in artificial recovery areas were greater than those in the river natural forest areas, which indicated that the mangrove vegetation in the early development was beneficial to the habitat complexity in mudflat ecosystem as well as to the diversity of benthic fauna. Moreover, the low macrobenthos diversity, evenness and richness demonstrated that the entire system was in the early stages of biological succession.

Due to data sparsity, volcanic activity in the Xisha waters is poorly understood. Single channel seismic profiles are used to study the volcanoes’ structures and their formation mechanisms in this paper. Seismic profiles document 10 submarine volcanoes in the south XW. Inside the volcanoes, discontinuous but strong reflections are observed and interpreted as lava flows. In addition, seismic data show two isolated volcanoes intruding Quaternary strata in the western edge and middle XW, respectively. Stratigraphic contact relationship between the lava flows and surrounding sedimentary strata reveals that Pliocene and Quaternary are two main magmatic activity stages in the XW. We propose the formation mechanism of volcanoes in the XW be that upwelling mantle magma weakens mantle lithosphere, migrates along pre-existing fault, and then erupts to the palaeo-seabed.

Using offshore airguns and onshore explosions as seismic sources, along with portable seismic stations, permanent seismic stations and Ocean Bottom Seismometer (OBS) as a synchronously receiving array, a onshore-offshore 3D seismic exploration experiment was carried out for the first time in the Zhujiangkou area of the northern South China Sea. This paper introduces in detail the seismic data acquisition, observation system, data preprocessing method, and phase identification. A variety of seismic phases, including Pg, PcP, PmP, Pn, and Sg, can be clearly identified in most data collected by the permanent, portable seismic stations and OBS. Jointly using airgun and explosion sources, and dense stations receiving seismic signals simultaneously both on land and at sea, it can highly improve the ray coverage and cross overlap beneath the onshore-offshore transitional belt, which lays a foundation for obtaining fine crustal structure beneath such onshore-offshore area.

Research on seismic wave field decomposition and Gaussian de-noising and directional illumination in three- dimensional (3D) models will promote a wide application of seismic illumination based on the Poynting vector. In this paper, optimal angle illumination is found through obtaining the acquisition parameter by laying source in the target area, namely reversed illumination, then decomposing the wave field transmitting from best source position based on the Poynting vector, and using statistics on the energy of different angles. In addition, the de-noised wave filed obtained by Gaussian filter improves the stability and fidelity of wave field decomposition, which demonstrates the effectiveness of the method. Compared to the traditional ray-tracing illumination, illumination based on double way wave equation avoids high frequency approximation, whose information of wave field is more comprehensive compared with one-way wave equation and whose calculation is more efficient. With weighted de-noising, the fidelity and signal-to-noise ratio of the wave field are improved. Moreover, the method is developed in the 3D model to realize dip illumination and azimuth illumination. These results not only provide scientific basis for seismic observation system of complex 2D geological model, but also offer a base for future applications in optimization of 3D acquisition parameters, which is advantageous to promote applied domain of the Poynting vector.

The exploration has lasted for 39 years in the eastern Pearl River Mouth Basin, where the process of reserves discovery, compared with that of other basins, has characteristic features in some ways and similar features in some other ways. The factors affecting reserves discovery in the area include internal factors and external factors. The internal factors are the type and geological characteristics of the basin, and the unique marine exploration environment. The external factors include exploration stage, exploration investment, and theory and technology. Based on the oil and gas geological features, exploration history and current situation of the study area, considering various factors influencing the reserves discovery in the area, and by studying and comparing prediction models, we establish the reserves development trend model of the area. We believe that, on the premise that there is sufficient investment, and that both theory and technology develop constantly, the exploration life course of the area can be divided into early stage (1977-2032, the speed of ascertaining reserves is less than 0.7%), peak stage (2033-2081, the speed of ascertaining reserves is greater than 0.7%) and atrophy stage (1982-, the speed of ascertaining reserves is less than 0.7%). At the end of the early stage, about 20% of the oil and gas resources will be found; and at the end of the peak stage, the number is 57%. The peak year is around 2055 when the number is 37%. At present, the study area is in the final phase of the early stage, and the annual proven reserves increase rapidly. The paper serves as a reference for accurately grasping main factors influencing reserves discovery in the area.

The characteristics and variation of mid-depth zonal jets in the tropical Pacific Ocean are examined using the trajectory of Argo floats. The method to estimate zonal intermediate currents based on Argo trajectory data is more appropriate in the equatorial region because it is free of the restrictions imposed by the methods based on the referenced velocity and Coriolis force. The results indicate that in the equatorial Pacific Ocean, the mid-layer (1000 dbar) zonal jets have a symmetric band-like structure in both Northern and Southern Hemispheres. The strong jets are centered near the equatorial regions, whereas there are several eastward zonal jets in the off-equatorial ocean (9°N, 13°N, 18°N). In addition, the characteristics of temporal variability are relatively complex. In the near-equatorial area, seasonal scale is the major and most important component, while in the off-equatorial region multiple time scale processes dominate. The Rossby wave dynamics and local response probably contribute to this difference.

In this study, we investigate the Northwest Pacific anomalous anticyclone (NWPAC) associated with Indian Ocean warming and its impacts on ocean circulation and sea surface height in the northwest pacific by using the reanalysis wind, current and sea surface height data of National Centers for Environmental Prediction (NCEP) and SODA v2.2.4 during the period of 1971 to 2010. Composite results reveal that the NWPAC associated with Indian Ocean warming is the strongest during the boreal summer and it has significant impacts on the upper-ocean circulation and sea surface height in the NW Pacific. The anticyclonic wind anomaly produces a negative wind stress curl, inducing convergence of sea surface water and the resultant positive sea level anomalies. The effect of NWPAC on the upper-ocean circulation in the South China Sea is synchronous, while its impact on the upper ocean east of the Philippines delays by about one season and peaks in the boreal autumn. This may be attributed to the modulation of westward oceanic Rossby wave.

In situ hydrographic data of sea surface salinity (SSS) revealed a freshening trend in the northern South China Sea (SCS) during 2004—2012, which was the freshest in 2012. Such freshening was also found in the UK Met Office EN4 objective analysis product and the ocean general circulation model for the Earth Simulator (OFES) output during 1993-2014, particularly west of Luzon Island and in the southeastern SCS. The salinity budget analysis in the upper layer indicated that the fresh water forcing and horizontal salinity advection contributed to the trends of SSS west of Luzon Island and in the western SCS, respectively. The excessive precipitation in summer accounted for the decrease of SSS to a great extent west of Luzon Island, which was associated with the strengthening trend of the Walker Circulation.

Based on the monthly mean data of Argo and Aquarius satellite observations, we analyze the seasonal variation of sea surface salinity (SSS) in the tropical South Indian Ocean. The results show that the SSS has significant seasonal variation characteristics, that is, the SSS is lower in winter and higher in summer in the region of 60°-80°E, 5°-15°S. However, the center of anomalous SSS does not correspond to the center of anomalous precipitation. The seasonal variation of precipitation cannot explain the seasonal variation of SSS. Salinity budget analysis indicates that the ocean dynamics contribute to the seasonal variation of SSS. During the summer half of the year, the SSS increasing is attributed to the meridional advection transport high salinity from the equatorial region to the South Indian Ocean, as well as the entrainment strengthening from April to May. In the winter half of the year, precipitation increases, the northward currents transport low-salinity water induced by increasing precipitation to the study region, which favors the accumulation of low-salinity water in the region; at the same time, the westward zonal advection transports the low-salinity water from the Southeastern Indian Ocean to the west, both of which have important contributions to the decreasing SSS.