Marine microplastics pollution is an emerging marine environmental issue and has attracted worldwide attention. Due to the special geographical environment characteristics, the coastal bays become the hotspot for microplastics distribution research. Here we report data on the abundance and characteristics of microplastics collected from surface seawater of the Jinzhou Bay. Samples were collected from 11 sites by horizontal trawling of a plankton net in October 2017. Wet peroxide oxidation process and micro Fourier-transform infrared absorption spectroscopy were conducted to remove the organic material mixed in the sample and identified the composition of microplastics. The research results showed that the average abundance of microplastics in the Jinzhou Bay was (0.93±0.59) items/m³, and accounting for 96.2% of the total plastic debris. Polypropylene and polyethylene were the main components of microplastics, accounting for 55.0% and 23.5%, respectively. The main types of microplastics were lines and fragments, accounting for 41.7% and 26.2%, respectively. White, blue and translucent was the most common color, accounting for 35.1%, 26.0% and 21.4%, respectively. Affected by hydrodynamic conditions and riverine input, the spatial distribution of microplastics in the surface seawater of the Jinzhou Bay was higher in the north areas than that in the south.

In order to study the effect of hypoxia stress on serum of biochemical and non-specific immune indexes of the juvenile cobia(Rachycentron canadum), the fish with body weight of (50.44±2.78) g were treated at dissolved oxygen content of (3.15±0.21) mg/L for 4 weeks. The samples were taken on 1 d, 7 d, 14 d and 28 d respectively for determination of relevant indexes and results showed that: (1) the growth of juvenile cobia was inhibited by hypoxia, the weight gain rate and specific growth rate were significantly lower than the control level (p<0.05); (2) the indexes of liver function showed that activities of aspartate aminotransferase and alanine aminotransferase significantly increased (p<0.01) on 7 d, 14 d, 28 d and 14 d, 28 d respectively, while the content of total protein and albumin significantly increased (p<0.05) on 14 d and 28 d than that of the control group; (3) the content of blood glucose significantly increased (p<0.05) on 1 d, 14 d and 28 d, while the triglyceride significantly increased (p<0.01) on 14 d and 28 d. The total cholesterol content significantly decreased (p<0.05) on 1 d, then continue to increase; (4) the serum ion content changed with different trend, in which sodium ion and chloride ion significantly increased (p<0.01) on 14 d and 28 d. Potassium content increased continuously and was significantly higher (p<0.05) on 7 d, 14 d and 28 d than control level, while calcium content continued to decrease and there was a significant difference (p<0.05) on 14 d and 28 d; (5) activitie of superoxide dismutase and content of malondialdehyde continued to increase and were significantly higher (p<0.01) than those in the control group on 7 d, 14 d, 28 d and 14 d, 28 d respectively. Activities of catalase showed significantly “decreased-increased-decreased” patterns. Activitie of lysozyme significantly increased (p<0.05) on 1 d and then continued to decrease. These results showed that hypoxia stress caused oxidative damage to the juvenile cobia, inhibited its growth and led to significant change in serum biochemical and non-specific immune indexes, which indicating that the nutrient utilization and immune system of cobia were affected.

The Okinawa Trough is an initial back arc basin developed on the continental crust due to the subduction of Philippine Sea plate under Eurasian plate. It is a natural laboratory to study the basin evolution, magmatism and crust-mantle interactions in the early stage of back arc expansion. Although a lot of investigations and research works have been done so far, there are still some controversial or urgent scientific problems, such as the genetic relationship between acid pumice and basic basalts in the trough, the control of tectonic background on magmatism in different sections of the trough, the characteristics of magma-derrived mantle, and the influence of subduction plate components (fluid + melt) on the mantle wedge, etc. On the basis of systematically collecting and sorting out (excluding some doubtful data) the major element, trace element (including rare earth elements) and Sr-Nd-Pb isotopic data of volcanic rocks in the Okinawa Trough, the author further confirmed the magma homology of acid pumice and basic basalt through systematic analysis of the data, and believed that the distributions of acid pumice and neutral andesite in the north and middle sections of the trough should be the reflection of regional rift at present, while the basic basalts widely distributed in the south section indicate that they are close to mature back arc basin in structural property. The volcanic magma source area of Okinawa Trough has the characteristics of enriched mantle II (EMII)-type Dupal anomaly, and the magma comes from the source mixed by end-member of prevalent mantle (PREMA) and EMII type mantle end-member, of which the ratio of EMII is about 15% and PREMA about 85%. The addition of fluid/melt from subducted Philippine Sea plate (subducted ocean crust or sediment) is the reason for the EMII type characteristics of magma-derrived mantle beneath the Okinawa Trough, which is different from the viewpoint that the Dupal anomaly originates from the interaction between crust and mantle.

The diffuse attenuation coefficient (K_d) is an important marine optical parameter, which can provide the basic data for the water environment change, the water quality analysis and the aquaculture. There are some limitations of the traditional methods, such as the low efficiency and resolution of the traditional shipborne field measurement and the rough inversion accuracy and spatial resolution of the satellite remote sensing. Therefore, an extraction method for diffuse attenuation coefficient based on airborne LiDAR bathymetric water column waveform is proposed in this paper. Firstly, the water column contribution is decomposed by the waveform decomposition algorithm for airborne LiDAR bathymetry based on the layered heterogeneous model. Then, according to the attenuation characteristics of laser in water, the diffuse attenuation coefficient extraction model is constructed. Finally, the diffuse attenuation coefficient spatial distribution in a large area of water is obtained. The performance of the proposed method was verified by the measured data from the Ganquan Island in the Xisha Archipelago and the Lianyungang’s seacoast. The experimental results demonstrated that the proposed method could obtain the diffuse attenuation coefficient without the water bottom contribution intensity and depth information for each bathymetric point. And the good results were also achieved in turbid waters. Meanwhile, the proposed method showed the feasibility of employing the ALB system to obtain the high-precision diffuse attenuation coefficient in China coastal waters.

In the present study, the connection between the Arctic Oscillation (AO) in May and the following summer (June to September) western North Pacific tropical cyclone genesis frequency is investigated based on NCEP/NCAR reanalysis data and tropical cyclone data from China Meteorological Administration for the period 1950–2018. A statistically significant positive correlation is found between the late spring AO and summer tropical cyclone genesis frequency. The diagnosis results show that the low-level relative vorticity, high-level divergence, vertical wind shear and the mid-low level relative humidity are all beneficial for the genesis of the western North Pacific tropical cyclones during the positive AO years. Moreover, the western Pacific subtropical high shifts eastward and northward and tends to be much weaker. On the contrary, during the negative AO years, the tropical cyclone formation is reduced because of the strengthened western Pacific subtropical high combined with an anticyclonic vorticity in the lower troposphere. The possible mechanism involved the variations of the storm track in the North Pacific. It is showed that during the positive (negative) AO years the storm track is moving northward (southward) and there is a cyclonic (an anticyclonic) vorticity anomaly in the lower troposphere in the western North Pacific in the subsequent summer through the interaction between the synoptic-scale eddies and low-frequency mean flow. The resulting anomalous local Hadley circulation could lead to the change of the western Pacific subtropical high and further contribute to the western North Pacific tropical cyclogenesis.

It is no doubt that there is plenty of “water” (existential form: H₂O, H₂ and (HO)⁻) existing in the mantle which can either exist in the form of fluids and melts or exist in aqueous minerals, nominally anhydrous minerals (NAMs) and dense hydrous Mg-silicates (DHMS). In this paper, “fluid” mainly refers to water which includes elements and compounds that dissolved in or migrated with it. Fluids, mainly consisting of water, play important roles in major geologic processes such as subduction zone earthquakes, mantle partial melting, magmatism and submarine hydrothermal activities. The subduction zone is a key place where the hydrated oceanic lithospheric plate subducts into the earth’s depth. And it is also an important zone of crust-mantle interaction. In the subduction zone, fluids are carried into the deep earth by the subducting lithospheric plate, part of the fluids are released into the overlying mantle wedge by extrusion, frictional heating and metamorphism, thereby lowering the melting point of mantle materials and causing magmatism; on the one hand, the ascending magma heats seawater that penetrates through cracks or rifts; on the other hand, the heated seawater and post-magmatic fluids generated by magma cooling compose the material basis of modern submarine hydrothermal activities; submarine hydrothermal activities not only affect the material composition of ocean water and ecological environment by importing a large number of underground elements or substances into ocean water, but also lead to the formation of hydrothermal polymetallic ore deposits with important economic value. Therefore, the fluid is a medium in the plate subduction process and the various important geological processes caused by it, thus it is a tracer to study these important geological processes. Based on the analysis of the main geological processes of fluids in the oceanic lithosphere subduction, this paper discussed the roles of fluids in earthquake mechanism, magmatic processes, modern submarine hydrothermal activities and subduction zone fluid mineralization. Furthermore, it is suggested that the recent research work should focus on these four aspects: (1) Making the assessment of the fluid flux subducted into the deep earth more accurate to solve global geochemical or material circulation problems. (2) Describing physical and chemical behaviors of fluids in plate subduction comprehensively and accurately, establishing theoretical models of fluid geological processes in subduction zones. (3) Making full use of modern tests and analysis methods, and obtaining accurate data in terms of in-situ analysis of minerals, testing physical and chemical indexes of fluid inclusions in minerals, stable and radioactive isotope analysis, etc., so as to find out the state and process of substances deep underground which can not be reached by current sampling and observation methods. (4) Developing numerical simulation technique to establish theoretical models of geological processes of fluids in subduction zones.

A submarine mooring system was deployed in the east of the Luzon Strait and the vertical distribution of high frequency (mostly tidal) variations of ocean currents were analyzed in the paper. Several features were revealed that the tidal kinetic energy of the middle (1 550 m) and the deep layers（2 560 m） was one to two orders smaller than that of the subsurface layers (100−160 m) , and slightly smaller than that of the near-bottom layers (4 040 m); the tidal currents were irregular semi-diurnal in the subsurface layers and were irregular diurnal in the middle and deep layers; the tidal kinetic energy was larger in summer (June to September) and winter (February to March) , which mainly caused by enhancement of M₂ and K₁ tidal components in corresponding periods; the high frequency fluctuations in all layers were mainly in clockwise rotation; the near-inertial frequency in the upper layers (middle and deep layers) were close to (slightly smaller than) the local inertial frequency.

In order to find an effective way to reverse the decline in the health of the oceans, the United Nations has decided to launch the "United Nations Decade of Ocean Science for Sustainable Development" (hereinafter referred to as the "Ocean Decade") since 2021. The Implementation Plan of Ocean Decade, which has been aceepted by the United Nations General Assembly on September 31, 2020, outlines the Ocean Decade’s vision of “building the science we need and the ocean we want”, and sets out the outcomes, challenges and objectives of the Ocean Decade, as well as mechanisms for implementation, governance, coordination, financing, monitoring and review. Described by the United Nations as a “once in a lifetime” programme, the Ocean Decade is a comprehensive United Nations-sponsored capstone programme for Ocean Megasciences that will build stronger science and technology innovation-based governance system at the global and national levels by inspiring and driving change in marine science. This will profoundly change human cognition and behavioural patterns towards the oceans, profoundly influence and even guide the evolution of the marine order, and have a great impact on the overall layout of regional cooperation in the oceans. It is suggested that China, guided by the concept of the “Marine Community with Shared Future”, actively participate in the Ocean Decade as a core means of deepening its participation in global ocean governance, and establish the Ocean Decade National Committee as soon as possible, and develop a Chinese programme of action to advance the sustainable development of the oceans and seas together with the international community.

It is a common ocean phenomenon that eddies attract each other and propagate in the form of dipole mode, and these dipoles play an important role in transporting seawater, nutrients and other substances. In this paper, a global dipole pair automatic recognition method based on the eddy trajectory data is proposed. By using the K–D tree for cutting space, the eddy trajectory data are calculated from January 1993 to September 2016, and a total of 86 662 westward moving dipoles and 30 590 eastward moving dipoles with a life cycle of more than 60 days are found. The global characteristics of the dipole that we detected are analyzed, and the reliability of the automatic recognition algorithm is verified by the comparison and test with sea surface temperature anomaly and sea surface salinity anomaly. Finally in this paper, the transmission modes and characteristics of dipoles are analyzed, including the characteristics of long life, high propagation speed and entanglement trajectory.

The occurrence of phosphatization will lead to the dilution of major ore-forming elements in polymetallic crusts and thus inhibit the growth of crusts in general. Phosphatization occurred in the Pacific Ocean in an episodic manner, and the occurrence periods correspond to the phosphatization layers in crusts and the geochemical characteristics of P, Ca and other elements, providing evidence for the dating of crusts. However, due to the frequent occurrence of phosphatization in multiple layers of crusts, a more reliable age frame needs to be determined before it can be mutually corroborated with phosphatization events. In this study, the Co-Os dating system with large dating range and the ability to determine hiatus was applicated in dating for the crust samples from central Pacific and western Pacific. With the naked eye identification of phosphatization mineralization features and geochemical profile characteristics, the age frames were proved and the effect of phosphatization on crust mineralization were discussed. The two large-scale phosphatization phases of 39–34 Ma and 27–21 Ma all correspond to the large-scale discontinuous phases of the crusts, while most small-scale phosphatization events in 71 Ma, 55 Ma and 31 Ma can be identified in the layers and geochemical profiles, corresponding to the rising and peak characteristics of P and Ca content. On the one hand, it is confirmed that the occurrence of phosphatization inhibits the growth of crusts, and has a wide range of influence area and a clear time interval in Pacific. On the other hand, it proves the accuracy of the chronological framework of polymetallic crusts.