Coelomocytes in Apostichopus japonicus, present in coelomic fluid and water-vascular system, are considered to participate in a variety of biological functions including nutrition transport, metabolism and immunity. In the process of evisceration, coelomocytes in coelom are nearly exhausted and then recovered in a short period. The polian vesicle, as the only remained internal organ after evisceration, shows positive response that coelomocytes within it increased rapidly. Coelomocytes in coelom are nearly exhausted after evisceration, and then recovered quickly. To further investigate the function and significance of the rapid increase of coelomocytes in the early stage of regeneration after evisceration, transcriptome sequencing was performed for coelomocytes in polian vesicle and coelom of A. japonicus at 6 h after evisceration and pre-evisceration, respectively. The gene expression differences of coelomocytes in polian vesicle and coelom after evisceration were analyzed compared to those of healthy A. japonicus. These results showed that 267 genes were differentially expressed in coelomocytes of polian vesicle at 6 h after evisceration, and most of these genes were enriched into the enzyme catalytic activity subclasses according to GO functional annotation and glycine, serine and threonine metabolism pathway according to KEGG pathways annotation, respectively. Additionally, 922 differential genes were significantly expressed in coelomocytes of coelom at 6 h after evisceration, and these genes were enriched into cell adhesion and biological adhesion subclasses according to GO functional annotation and ECM-receptor interaction, TGF-β signaling pathway, FoxO signaling pathway according to KEGG pathways annotation, respectively. The results provide an important basis for further functional research and the regeneration mechanism of coelomocytes after evisceration in A. japonicus.

Algae are general term of a large group of photoautotrophic aquatic sporophytes. Along with the long earth history, the algal light-harvesting antenna has evolved special structure and function, to adapt to low-light underwater environment. Since the algal light-harvesting antennas were first discovered 70 years ago, the progress of structural analysis can be divided into four stages. The first stage was from 1950 to 1980, and effects were focused on studying the structural composition of light-harvesting antenna through biochemical and spectral techniques. The second stage was from 1980 to the present, and X-ray crystallization becomes a primary tool to study the partial fine-structure of the complete complex. The third stage was from 1980 to 2010. In this stage, complete contour structure can be studied by using electron microscope (EM). The fourth stage is from 2010 to the present, and the use of cryo-EM technology to studied intact fine-structure has brought the blowout period of structural analysis in recent year. With the rapid development of cryo-EM technology, a variety of complete fine-structures of algal light-harvesting antenna complexes have been analyzed, including cyanobacteria, red algae, green algae, and diatoms. Specifically, in 2019, multiple super-molecular complex structures of algal light-harvesting antenna were resolved. This breakthrough provides us valuable structure information for the study of energy transfer and the unified relationship between structure and function. However, the synthetic understanding of the relationship between the structure, function, environment, and applications of algal light-harvesting antennas is still preliminary, compared to the huge demand of solar energy utilization from bio-materials. Therefore, further research on the light adaptability of light-harvesting proteins has become the focus of the future, and will provide a sufficient scientific basis for the application of algal light-harvesting antenna proteins in the field of photoelectric devices.

The modern Zhujiang River Delta has experienced the formation and evolution from drowned valley to delta, which is rich in regional characteristics. The research on the Zhujiang River Delta in the past hundred years is summarized into four paradigms: historical description, field investigation-scientific reasoning, instrument applied-discipline theory and “dynamic-sedimentary-morphologic” scale-crossing paradigm. Each illustrated by superb examples and documented. Based on the research of the authors and his team, this paper puts forward several propositions concerning the formation and evolution of the Zhujiang River Delta, which are substantially different from the existing literature, and makes necessary differentiation and analysis from multiple perspectives, including the millennial-scale changes of coastline since the transgression maximum, the mode of formation and evolution of the modern Zhujiang River Delta and the development and its mechanism of the major channels of the network in the delta. Finally, the approache of interdisciplinary, scale-crossing and time-space quantification concerning delta research are briefly discussed.

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.

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.

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.

Based on the hybrid detection method for ocean mesoscale eddy, this paper uses the measured data to verify the detected boundary and center of eddy, and draws the following conclusions. (1) By diagnosing the angle between the detected boundary and the measured current vector, the results show that the detected boundary of eddy can basically reflect the current state of the actual eddy. (2) The center of detected eddy is compareed with the center that inversed by the measured current and temperature data. The results show that the detected center of eddy is basically consistent with the inversed center. Furthermore, by comparing the fitting effect of circle and ellipse to the detected boundary of eddy, the results show that the fitting accuracy of ellipse is higher than that of circle.

Based on the WRF (Weather Research and Forecasting Model) and its three-dimensional variational data assimilation system, the numerical simulation and Doppler radar data assimilation are conducted with the data of GFS (Global Forecasting System) and JMA (Japan Meteorological Agency) reanalyses as the initial conditions respectively. The impact of assimilation radar data in different background fields on the initial typhoon field, internal structure and forecast were investigated based on the super typhoon case Saomai in 2006. The results show that, both experiments with GFS and JMA data are able to enhance the typhoon initial winds field at 700 hPa and geopotential height field at 500 hPa after assimilating radar observations. The improvements in terms of the root-mean-square error during the 3 h during the data assimilation cycling, the minimum sea level pressure, and the thermal and dynamic structure from the JMA tests are more significant than that with GFS data. The forecast skills for the precipitation, the typhoon track, and the intensity are also noticeable with JMA data by correctly predicting the precipitation location in the front of typhoon.

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.

The risk assessment and zoning of submarine landslides can guide the site selection and risk prevention of offshore engineering facilities. In this paper, an unsupervised machine learning spectral analysis algorithm was used to evaluate the risk of submarine landslides in the Chengdao sea area of the Yellow River Estuary. A model of submarine landslides risk assessment with 9 input parameters, 4 output parameters and 0.08 as kernel function parameters is constructed. By using this model, the study area can be divided into 4 parts: high, quite high, quite low and low risk of submarine landslide. The comparison between the evaluation results and the distribution characteristics of geological environment factors show that the most important factors are the type of seafloor sediment and hydrodynamic action, and the most important trigger factor is liquefaction. The analysis results of model parameters present that the evaluation results with slightly lower accuracy can be obtained by reasonably simplifying the input factors, and the kernel function parameter is important index affecting the evaluation accuracy. The above research shows that the unsupervised machine learning algorithm can be well used in the risk assessment of submarine landslides, and the richness and accuracy of data categories are important factors affecting the assessment accuracy.