The salt-containing characteristics of soft soil are an important indicator of foundation design, and salt-containing features are mainly protected by deposition environment, often with strong geographicalism. In the Changjiang River Ekimae, the softener of the Changjiang River Ekimae is a research object, collecting multi-sets of soil samples for indoor trials, and conducts salt-containing characteristics, parameter correlation and deposition environment analysis. The results show that the salt-containing salt is NaCl type, the salt content is 0.613%, mainly based on weak saline soil, accounting for 85.4%. The salt content, Cl⁻ content, Na⁺ content, K⁺ content peak test meets the regular distribution, but the reputation test value is located in the rejection domain, and does not belong to normal distribution. Other ion assumptions and peak tests do not comply with the right to distribution. The salt content of soft soil is highest in relationship with Cl⁻content, and is good to ion-relevance to the Ca²⁺ content and ${\rm{CO}}_3^{2-} $. The content of the soil-solvent Cl⁻ content and salt content, the ${\rm{SO}}_4^{2-} $ content is equipped with the highest multiplication effect; Cl⁻ content is best fitted with Na⁺, Ca²⁺, Mg²⁺, K⁺, ${\rm{HCO}}_3^- $ contents fitted to polynomial fitting effect. The soft soil is deposited by an alkaline environment. The sodium adsorption ratio of soft soil is 54.35, which is close to the sodium adsorption ratio of seawater, indicating that the salt-containing characteristics retains the seawater characteristics, and with the increase of depth, soft soil sodium adsorption ratio has reduced trend. The soft soil formation time is related, the older the formation of soft soil, the longer the time of penetration. The Sr/ Ba value of the soft soil is much greater than 1, indicating that the soil deposition environment is a marine environment. The γ_Mg/γ_Ca value in the soft soil leaching solution is much higher than the γ_Mg/γ_Ca background value, which is subjected to seawater dipping. The seawater mixing model is introduced, and the seawater mixing ratio is calculated. The low value of the seawater mixing ratio is mainly distributed in the west far away from the coast, and the soil deposition in this area is mainly controlled by the water of the Changjiang River. The high value of seawater mixing ratio is mainly distributed in coastal areas, where soil deposits are mainly controlled by transgression, and the marine facies attributes are heavier.

Bacterial membrane vesicles (MVs), which are a kind of biological nanoparticles carrying proteins, nucleic acids, signaling molecules, and other important compounds, are involved in a variety of physiological and biochemical processes, such as horizontal gene transfer, quorum sensing, biofilm formation and so on. Studies showed that marine extracellular vesicles might be the third largest biological entity except for phages and bacteria. Besides, MVs-mediated intercellular communication across species could be of great significance to marine ecosystems. However, very little is known about the specific ecological role and biological function of MVs in the marine biosphere. In this review, we discuss the role of bacterial MVs in marine micro-ecology, marine symbiotic system, and the impact of MVs-mediated material delivery on marine ecosystem. Meanwhile, we also put forward some questions and opinions for study in marine bacterial MVs’ research.

In recent years, various artificial intelligence algorithms based on big data have gradually emerged and have been applied in short-term time series wave forecasting. Based on the measured time series data of hourly waves in Hainan offshore from 2015 to 2019, a prediction model for long-term time series waves of Hainan offshore based on Prophet algorithm is established in this paper. The daily, monthly and annual variation characteristics of waves in Hainan offshore from 2015 to 2019 are analyzed, and the waves in Hainan offshore in 2020 are predicted. The results show that the predicted values of wave height and period by prophet algorithm model are in good agreement with the measured values. Prophet algorithm model can be effectively used for long-term wave characteristic analysis and time series prediction.

With the rapid economic development and increasing anthropogenic activities, the groundwater in the coastal area has been excessively exploited. The resulting seawater intrusion has become a widely distributed environmental geological problem. Taken the coastal area of Laizhou Bay as a research area, the dynamics of groundwater level (GWL) and electrical conductivity (EC) were analyzed with the continuous monitoring data. Based on the rainfall, evaporation, tide and agricultural irrigation and drainage electricity consumption that affect the groundwater variation, the hybrid model of wavelet analysis (WA) and NARX neural network was introduced to predict the dynamics of GWL and EC. The root mean square error (RMSE) and goodness of fit (R²) were used to measure the prediction accuracy. The results showed that the annual variation of GWL was characterized by a type of rainfall infiltration-exploitation. A significant correlation at the frequency of 0.5 d was observed between groundwater level and tide, and the influence of tide on EC was weaker than that on GWL. For the dynamics prediction with WA-NARX method, the RMSE was less than 0.03 and R² was greater than 0.98 in both the training and testing stages. The results indicated the hybrid model had a good performance and could effectively predict the dynamics of GWL and EC. The effects of different influencing factors as model input parameters on the prediction results were further compared. The results showed that rainfall and tide parameters were the main variables affecting the GWL and EC variations in the coastal zone. The pumping information reflected by the evaporation and agricultural drainage and irrigation power consumption also affected the groundwater dynamics. The degree of influence was related to the observation frequency. The research results can provide theoretical and technical support for real-time monitoring, prediction and early warning of seawater intrusion in coastal zone.

We presented an optimized and purification procedure as well as an analytical method for Cu and Zn isotopes measurement in marine sediments. We reported Cu and Zn isotope of 5 samples in a sediment cores and 20 surface sediment samples in the northern and southern Okinawa Trough. Anion exchange resin (AG MP-1M) was applied to separate matrix elements of sediment samples from Cu, Fe and Zn using 8.2 mol/L HCl+0.01% HF+0.001% H₂O₂, 2 mol/L HCl+0.001% H₂O₂ and 0.5 mol/L HNO₃ as eluents. The recoveries of Cu and Zn were both close to 100%. Cu and Zn isotopes were measured on a Nu Plasma multi-collector inductively coupled plasma mass spectrometer (MC-ICP-MS). Instrumental mass bias was corrected using a combination of sample-standard bracketing and internal spiking. The long-term reproducibilities were 0.11‰ (2SD) for Cu isotopes and 0.09‰ (2SD) for Zn isotopes. The δ⁶⁶Zn of surface sediments varies from 0.07‰ to 0.67‰, with an average of 0.31‰ ± 0.32‰ (2SD); the δ⁶⁵Cu of surface sediments ranges from −2.26‰ to −0.52‰, with an average of −1.21‰ ± 0.55‰ (2SD). The results show that Cu and Zn isotopes of surface sediments in the Okinawa Trough varies widely, meanwhile, Cu and Zn isotopes in sediment core varies with depth.

Based on mesoscale eddy dataset from February 1993 to January 2016, the distribution characteristics and evolution processes of mesoscale eddies in the Indo-Pacific Warm Pool (15º S~15º N, 60º E~170º W), and its seasonal variation and relationship with ENSO are statistically analyzed in this paper. It shows that most mesoscale eddies in the Indo-Pacific Warm Pool are short-lived and nonlinear, and propagate westward. The study also finds that the distribution characteristics of cyclonic eddies and anticyclone eddies are similar, and so do their variation trends over the eddy lifecycle. The seasonal numbers of mesoscale eddies vary insignificantly in the whole domain and are affected by ENSO in the meanwhile.

Three monthly altimeter datasets of the Arctic Ocean are compared in this paper. The datasets provided by the Centre for Polar Observation and Modelling (CPOM) and Technical University of Denmark (DTU) are found to be consistent with each other and due to their high spapce coverage, are more suitable for the study of the sea level variation in the Arctic Ocean, the former is better in terms of spatial resolution, smoothness, and consistency with the tide gauge observation. Based on the data of both altimeter and tide gauge, the temporal and spatial characteristics of sea level in the Arctic Ocean are analyzed and the results show that the climatological sea level in the Arctic Ocean is represented by the striking contrast between the high values in the Canadian Basin and low values in the Eurasian basin. The variation of sea level in the Arctic Ocean is dominated by the seasonal variability and low-frequency variability associated with the Arctic Oscillation, large amplitudes of both the seasonal and inter-annual sea level variability are found in the Canadian Basin, and large seasonal variability occurs along the coast of Russia. During the period 2003−2014, the mean sea level of the Arctic Ocean is rising with the largest rising rate is found in the Canadian Basin, while the sea level in the Russian coastal area is declining slightly. It is also found that large uncertainty exists in the altimetry products of the Canadian Basin and the coast of Russia, as the difference both between altimetry products and between altimeter and tide gauge data cannot be ignored, data in these areas should be used with caution.

Morphodynamic relationships between fringing reefs and back-reef beach play key roles in understanding the evolution of coral coasts. The fringing reef coasts of Leizhou Peninsula, in Xiluo Port, Xuwen, are taken as the research object in this paper. RTK-GPS and unmanned-surface-vessel are used to measure and analyze the topography of the beach profile and reef as well as the sediment sampling in beach. FUNWAVE-TVD is used to simulate and analyze the hydrodynamic process of short wave and infragravity wave cross the different reef. The results show that the reef topography in the study area has significant effects on the morphology of back-reef beach. Whether the nearshore wave energy dominated by the short wave band or the infragravity band is controlled by the topography. In the narrow reef, there is a predominance of infragravity energy near the back-reef beach. The dominated wave band in the nearshore wave energy is the main factor shape the back-reef beach equilibrium profile. However, the beach equilibrium profile model of coral coast proposed by Muñóz-Pérez did not take this factor into account, it need to further research.

In this paper, using the equatorial beta-plane approximation of the linear barotropic perturbation equations and introducing the reduced gravitational acceleration, we obtain the analytical solutions of anomalous equatorial ocean stationary wave and give the calculation results of the solutions. Then we compare the results with the modes of complex EOF analysis about abnormal circulation of the real tropical Pacific Ocean and Indian Ocean. The main conclusions are: in the first mode of anomalous equatorial ocean stationary wave, the current disturbance throughout the whole ocean is the half wave, which appears as the consistent zonal flow. The maximum disturbance appears at the middle of the tropical ocean and decays rapidly from equator to north and south, which is restricted in about 2 degree range on both sides of the equator. In the second mode, the current disturbance throughout the whole ocean is the full wave and has the opposite flow direction at east and west of the ocean. The degree of the attenuation of the current disturbance from equator to north and south is as that of the first mode. Anomalous equatorial ocean stationary wave meets the boundary conditions of the east and west coast directing along the longitude. The coefficient is inversely proportional to the square root of the product of the reduced gravity acceleration and the upper water standard depth, which determines the decay rate of anomalous equatorial ocean stationary wave on both sides of the equator. If the square root values take the same, the decay rates are the same. The oscillation frequency of anomalous stationary wave is proportional to the modal number and the square root values, which is inversely proportional to the width of tropical ocean. The modal number is lower and the width is larger, the frequency is lower and the corresponding oscillation period is longer; the first mode of the oscillation period is the longest. Taking every parameters as the typical values and the modal number as one, then taking the width of the equatorial Pacific Ocean and Indian Ocean respectively, the calculation results show that the spatial distribution and interannual variability of the first mode are the same as the corresponding mode of the real abnormal circulation obtaining from the complex EOF analysis; this means that the nature of the first mode above is the anomalous equatorial ocean stationary wave and the anomalous stationary wave is one of the generating mechanism of ENSO and IOD.

Water transparency (Z_sd) is an important optical parameter for evaluating water quality. This paper tuned a remote sensing model for estimating Z_sd from MODIS (moderate resolution imaging spectroradiometer) data in the South Yellow Sea. This model was then used to analyze the spatial and temporal variations of Z_sd in the South Yellow Sea based long-term MODIS data in the past 20 years (2002–2020), and their driving factors were examined. The results show that the Z_sd estimation model has good accuracy with R², root mean square error and mean absolute percent error values of 0.91, 1.69 m and 25.1%, respectively. The Z_sd levels are generally high in the offshore but low in the coastal area. Meanwhile, Z_sd indicates high values in summer but low values in winter. In the past 20 years, Z_sd in the central South Yellow Sea, the southern South Yellow Sea and the Changjiang River Estuary showed slowly increase trends, while Z_sd in the Jiangsu coast was decreasing slowly. In general, the Z_sd is negatively driven by the concentration of suspended particulate matter, of which the influence is the greatest. In addition, sea surface temperature and solar radiation have positive driving effects on Z_sd, while wind speed has negative driving effect.