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The UK Met Office EN4 analyses product revealed that the surface area and the volume of the North Pacific subtropical high-salinity center, namely North Pacific Tropical Water (NPTW), decreased in the period of 2000-2008 and 2014—2017, and grew in 2008—2014. The changing period of NPTW was highly correlated with Pacific Decadal Oscillation (PDO). Using the ECCO2 reanalyzing data, the fresh water flux was calculated through the NPTW surface. Our results show that the fresh water flux has less contribution to changes of NPTW, while the horizontal advection contributes significantly to the surface area and volume changes of NPTW, which is related to the northward(southward) swing of North Equatorial Current (NEC) during the PDO positive(negative) phase.

To investigate monochromatic wave nonlinear characteristics around coral reefs with large surface roughness, laboratory experiments were carried out in a wave flume. A cylinder array was used to model the reef roughness and a series of monochromatic wave conditions were tested. Results show that magnitudes of the wave skewness, the wave asymmetry and the Ursell Number reach their peaks at the endpoint, in the interior and at the stating location of the reef surf zone, respectively. All the three parameters increase with the increasing wave height. Meanwhile, the skewness decreases with the increase of wave period while both the asymmetry and the Ursell Number increase with the increase of wave period. Moreover, the skewness increases with the increase of reef-flat water level while both the asymmetry and the Ursell Number decrease with the increase of reef-flat water level. The deep-water Ursell Number is able to describe the variations of the three examined parameters on the reef flat, and the empirical formulas are finally proposed in this study to predict these parameters.

The polymetallic nodule samples were analyzed for their mineralogical and geochemical features, which were acquired on the northeastern slope of the South China Sea using the ROV named as Sea Dragon III. The results showed that the nodules in the study area were predominantly by rod-shaped with a two-layer structure. The outer layer of the polymetallic nodules was mineralogically and geochemically similar to hydrogenic nodules. While the inner layer was porously and composed of goethite with residual minor pyrite. Geochemically, the inner layer was characterized by high concentration of Fe and As but extremely low concentration of Mn, REE and other elements. The inner layer carbon isotopes ( δ¹³C ) of sample NH-2 was -30.91‰. The study presented that the early forming process of the nodules was related to the activities of cold seep, but the pyrite was oxidized following the extinction of cold seep. Under the influences of contour current in the area, the ferromanganese oxides continued to grow in the outer layer of the nodules.

The Landsat TM/OLI remote sensing images from 1973 to 2018 were obtained as the data source by using the remote sensing and GIS technology. Based on the geographical background information, the spatial and temporal evolutions of the coastline in the Pearl River Delta region over 45 years were analyzed. The results show that the Pearl River Delta changed significantly, a large number of muddy coast changed into urban industrial coast and port coast. The artificialization index of Pearl River Delta coastline was rising, the types of coastline were developed in a diversified direction, the total length and fractal dimension of shoreline were increasing continuously, the main factors of increase shoreline length and fractal dimension were port construction, coastal industrial zone and reclamation.The evolution of the coastline had obvious regional characteristics, and the regions with large changes were mainly concentrated in Shenzhen Mirs Bay, Guangzhou Nansha and Zhuhai Doumen. From the perspective of the main structure of shoreline, each region presented different type changing tendency, substituted the natural shoreline, the industrial and port shorelines became the main type in each region. The intensity of development and utilization was increasing in various regions, among which the intensity of development in Shenzhen was growing the fastest. Social activities and location policies were the main driving factors for the evolution of shoreline.

In the past two decades, large scale blooms Prorocentrum donghaiense Lu (P. donghaiense) have frequently occurred in the coastal water of the East China Sea (ECS). Previous studies have shown that P. donghaiense blooms in the ECS originated from the front of Taiwan Warm Current (TWC) and expanded with its invading inshore. However, little is known about the location where the P. donghaiense blooms firstly occur, as it is limited by the investigation section of previous studies. In this research, four surveys in the East China Sea (24 °N-30 °N) in spring and summer of 2013 were conducted. Results clearly showed that P. donghaiense blooms occurred firstly at the northern end of the Taiwan Strait and spread northward and inshore with the invading of the front of TWC. It was not only confirmed again that the TWC played a seed bank role for P. donghaiense blooms in the ECS, but also confirmed the location where P. donghaiense blooms firstly occurred in the ECS. This research was useful to monitor P. donghaiense blooms and similar algal blooms.

The Comesomatidae are a group of free-living marine nematodes that widely distributed in the ocean sediments. The development and progress of systematics research of Comesomatidae are briefly summarized and key to the species of each genera is also provided. Our review recognizes 3 subfamilies, 19 valid genera, 239 valid species, 4 genera including 4 species without enough morphological information for accurate identification (species inquirenda).

In order to evaluate the ecological environment quality of the estuarine coastal zone, based on remote sensing information technology in land, a remote sensing assessment system of the ecological environment of the estuarine coastal zone was established.Through the analytic hierarchy process and the Delphi Method, the area of 5 km land forward along the coastline of Baoshan District was taken as an example to evaluate. The results show that the estuarine coastal zone of Baoshan District is dominated by industrial and mining warehousing land, and the ecological environment quality in this area gradually decreases from west to east, reaches the lowest point in the area between the Lianqi River and the Malu River, and starts to rebound to the east,the overall situation is poor.

The island is one of the core contents of the value of marine resources development and utilization. In order to reasonably develop, utilize and protect island resources in Guangdong-Hong Kong-Macao Greater Bay Area and optimize the industry structures and arrangement on islands, from the perspective of the spatial distribution of island resources, the role of islands in the development of the key platforms in Guangdong-Hong Kong-Macao Greater Bay Area was explored. The spatial distribution characteristics of islands in Guangdong-Hong Kong-Macao Greater Bay Area were investigated by application of ArcGIS software platform, Nuclear Density Estimation Method, Lorenz Curve and Gini Coefficient calculation based on the statistical data of 850 islands coordinates and land areas, which have been listed in the China Seas Island Standards Directory. The results show that the distribution type of islands in Guangdong-Hong Kong-Macao Greater Bay Area tends to be concentrated and presents the overall band distribution, the characteristics of local group distribution in space. The islands in Guangdong-Hong Kong-Macao Greater Bay Area have shaped the western part of the bay area and 4 obvious gathering areas,Including Dapeng Bay-Daya Bay Area, Kyushu Islands Area, Wanshan-Jia Peng Islands Area, Chuanshan Islands Area. The islands in Guangdong-Hong Kong-Macao Greater Bay Area are mainly coastal islands and the area distribution of islands is characterized by an imbalance, with a Gini coefficient of 0.58.

The Pearl River Estuary (PRE) is one of the coastal areas with serious land subsidence, which forms a serious threat to the quality and safety of human life and production. In response to the problems associated with the lack of man-made targets of traditional time-series Interferometric Synthetic Aperture Radar (InSAR) in estuaries and other coastal areas, a distributed scatterers InSAR (DS-InSAR) method based on a spatially adaptive filter and an eigendecomposition algorithm to estimating the optimal phase of statistically homogeneous DS was applied to obtain the deformation information in PRE between 2015 and 2018. High-density and high-coherence points were extracted in asphalt pavement, bare soil and other non-urban areas, to improve the inversion accuracy. The results suggest that land subsidence in the PRE was widespread and unevenly distributed. The northwest and southeast are the main subsidence areas, with a maximum subsidence rate greater than 25 mm/a.

In order to explore the biochemical and genetic characteristics of Scomberomorus niphonius, Gradient Polyacrylamide Gel Electrophoresis (GPGE) was used to analyze the expression patterns of eight isozymes (LDH, MDH, GDH, G6PDH, SOD, EST, SDH and MEP) in nine tissues (cardiac, gill, intestine, muscle, stomach, liver, eyes, kidney and gonad) of six individuals (3 females, 3 males) from Xiangshan Bay. The results showed that all eight isozymes were tissue-specific expression in nine tissues. LDH, MDH and G6PDH expressed in all nine tissues, while GDH only expressed little in the liver and eyes. Isoenzyme expressions were most abundant in liver among nine tissues. Eight isozymes were detected in the liver, in which the enzyme bands of EST were most abundant. GDH and G6PDH were more active in the liver than in other tissues. Isozyme expression patterns had no difference between male and female. The results provide a theoretical basis for the germplasm identification of Scomberomorus niphonius.