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The distribution of tropical cyclone (TC) track forecast errors in the northwestern Pacific Ocean were studied based on the Japan Meteorological Agency (JMA) 6-hour TC forecast data from 2005 to 2018. The relationship between track forecast errors and western Pacific subtropical high (WPSH) was also analyzed. The results show that the northeast and southwest displacements are the main track errors in all the 0, 24, 48, 72 h forecasts. The ratios of the northeast and southwest track errors to the total forecast numbers for the 24, 48, 72 h forecasts are 61.62%, 64.02%, 66.94%. There is significant difference in spatial distributions between northeast and southwest track errors. The former mostly occur around 16°N, and the latter around 24°N. Further analyzing the relationship between northeast-southwest biases and WPSH, it is found that 70% of northeast track errors occur to the southwest of the WPSH and about 60% of southwest track errors occur to the northwest of the WPSH. Compared to the WPSH in southwest track errors, the WPSH in northeast track errors has a more extensive area and a more northward ridge. The northeast forecast errors tend to happen in WPSH induced westward migration of TCs, and the southwest forecast errors tend to happen in WPSH induced northward migration of TCs.

Diatom mat deposits have been discovered in the tropical western Pacific successively, and its formation time and mechanism are of great significance for the study of carbon cycle in the tropical western Pacific. In this study, high-resolution XRF element scanning, color scanning and AMS14C dating analysis were performed on sediment of core E20, which contains nearly 2.5 meters of diatom mat deposit in the west Mariana Arc. The results showed that the core E20 could be divided into three sedimentary units, those were clay, siliceous ooze, siliceous clay from bottom to top, and elements Ti, Fe, Cu, Br, etc. showed three-stage change, Ca and Si showed reverse change. Based on 14C-AMS ages, E20 reflected the significant environmental changes in the western Pacific since the last glaciation, the bloom time of diatom mats was from 10.9 ka B.P. to 28.6 ka B.P., and the increase of dust input during the last glaciation should be the main reason for the diatom bloom in the oligotrophic tropical western Pacific. Local low-lying topography was conducive to the preservation of diatom mats.

The bacterial community structure of six surface sediment samples which were collected during the 48th China Scientific Cruise in the west Pacific Ocean was analyzed by highthroughput sequencing method. A total of 253012 sequences are obtained, belonging to 41 phyla, 85 classes, 189 orders, 261 families and 322 genera, respectively. Among them, Proteobacteria is the dominant class, which includes three subclasses: γ, α and δ. Their richness account for 24.76%, 20.21% and 6.48% of the total OTU(operational taxonomic units) in the study area, respectively. In addition, Chloroflexi, Acidobacteria, Gemmatimonadetes, Planctomycetes, Actinobacteria, Bacteroidetes and Nitrospirae are also found popular with abundant bacterial genera and species in each category. There are 23 orders with sequence abundance over 1%. Among them, 6 families or 10 genera are the highest dominant groups. Functional genes related to iron and manganese metabolism account for 10.20%, such as Alteromonas (6.90%), Pseudoalteromonas (1.80%), Shewanella (1.00%) and etc. Other functional gene groups related to nitrogen and sulfur cycling are also found. The result of PICRUSt analysis show wide genetic diversity of bacteria involved in various metabolic processes, such as signal transduction mechanism, protein transport, carbon fixation pathways in prokaryotes, quorum sensing, energy conversion, amino acid and pyrimidine metabolism and etc. Compared with other sites, BC1826 site has lower bacterial diversity, but has higher gene abundance of two-component system. Combined with the frequency of grain size curve of each sedimentary analysis, the result speculate that the difference of microbial community structure between BC1826 site and other sites is related to sedimentary disturbance. Based on the comparison with previous reports, the bacterial community structure in the western Pacific seamount area is different from that in the nodule areas of the eastern Pacific area.

Submarine groundwater discharge is a significant source of the rare earth elements (REEs) in the coastal waters, studies on the geochemistry of REEs in the groundwater are very limited. In this study, the distribution, influencing factors and complex speciation of dissolved REEs in the groundwater of Dagu River Basin in Shandong Province were examined by field investigation and simulation. The conclusions have been obtained as follows: the distribution of REEs in groundwater has a great spatial variation, pH and the reductive dissolution of Fe, Mn oxides/hydroxides may be the important factors affecting the concentration of rare earth elements. The REEs speciation mainly exists as LnCO+3 and Ln(CO3)-2. However light rare earth elements are more likely to form LnSO+4 than middle rare earth elements and heavy rare earth elements in the case of high sulfate. And the patterns of the REEs generally show heavy rare earth elements enrichment in groundwater, the preferential adsorption of LnCO+3 by electronegative particles in the aquifer may be the reason for heavy rare earth elements enrichment. Affected by surrounding refineries, all samples have positive lanthanum anomalies. The proportion of anthropogenic lanthanum in fresh groundwater and recirculated seawater are 34%-75% and 42%-57%, respectively.

Based on the measured Chl-a concentration and sea surface spectrum, the Chinese white dolphin inhabited area of Dajin Island in the Pearl River Estuary was taken as the study area, a Chl-a inversion model suitable for CASI aerial hyperspectral and MODIS satellite remote sensing images was constructed and Chl-a concentration inversion was carried out. The results show that the band ratio model has better performance based on CASI images. The Chl-a concentrations in the study area are 0.1-4.4 μg/L, and the relative average error is 14%. Inversed with MODIS, the Chl-a concentrations in the Pearl Estuary vary from 0 to 8 μg/L with relative average error of 17%. In general, the Chl-a in the sea water around Dajin Island is uniformly low. The Carlson eutrophic index calculated based on the concentration of Chl-a indicates that the sea area around Dajin Island is at the level of oligotrophic and mesotrophic, the complex hydrodynamic and high turbidity may be the main factors inhibiting the growth of phytoplankton in the study area.

Electrochemical methods are the main methods for measuring seawater pH. The self-developed electrochemical pH sensor is based on iridium metal and its oxide electrode, a method for its calibration and data correction in seawater environment was established and applied for in-situ testing in nearshore and oceanic environments. The instrument calibration includes (1)Selecting appropriate calibration buffer reagents according to the calibration requirements of seawater pH analysis; (2)Preparing calibration buffer system by replacing the commonly used 2-aminopyridine (AMP) solution with standard seawater. Data correction mainly includes temperature background correction and error correction. Insitu testing in the sea area and comparison with other similar instruments show that the error caused by the difference of calibration system can be up to 1.00 pH unit, and the data correction can improve the testing accuracy from 0.10 pH unit to 3.00 pH unit. The calibration and data correction method of the instrument can effectively improve the measurement accuracy of this self-developed pH sensor.

The evaluation of marine functional zoning implementation is an important tool to supervise the implementation effect of marine functional zoning and improve the planning management system. However, the lack of effective and stable mechanism for implementation evaluation makes it difficult for marine functional zoning to fully play its guiding role in China. Therefore, based on the concept of consistency and planning blue print, a method is put forward to judge the coordination between the current situation of marine utilization and the marine functional zoning from three aspects: the conformity of marine use, the conformity of environmental quality standards, and the influence of utilization and then constructs coordination index of marine functional zoning, in order to build scientific and operable marine functional zoning implementation evaluation method, and Wenzhou is taken as an empirical case. The results show that the evaluation method based on consistency concept and marine function zoning blue print can effectively measure the implementation effect of marine function zoning. The implementation effect of Wenzhou Marine Function Zoning after revision has been significantly improved, which suggests the revision is conducive to promoting marine function zoning to better meet the social and economic development needs of the planned region. The evaluation method can lay the foundation for the compilation of territorial space planning and provide a reference for the evaluation of territorial space planning.

 In order to study the composition and structure of rocky intertidal benthos community in uninhabited islands in Cangnan, Zhejiang, the intertidal benthos investigation was carried out on 11 uninhabited islands in March 2019. The collected samples were identified, and the abundance, biomass and biodiversity indexes were calculated. A total of 58 intertidal benthos species are identified in 11 uninhabited islands, the average density is 857±205 ind/m2 and the average biomass is 2 847.83±1 032.50 g/m2, the Shannon-Wiener diversity index H, Pielou evenness index J and Margalef richness index D are 1.07-1.61, 0.66-0.83 and 0.54-1.30, respectively. Compared with the mainland coastal intertidal zone, uninhabited islands have more distinct ecosystems with rich and diverse biological resources and important ecological values. It is suggested that uninhabited islands should be protected.

To better understand the effects of seasonal hypoxia on macrobenthic communities in Yangtze Estuary, 4 surveys were carried out during summer from 2016 to 2019. Results showed that the lowest bottom-water dissolved oxygen (DO) was 1.51 mg/L, and the bottom-water hypoxia appeared in the Yangtze Estuary in summer from 2016 to 2019. There were significant differences in the species number, abundance, biomass and community structure of macrobenthos between hypoxic zone and non-hypoxic zone. Polychaetes showed greater tolerance to hypoxia，and were the dominant group in hypoxic zone. Mediomastus sp. and Lumbrinereis sp. were the main dominant species in hypoxic zone. Mollusks, crustaceans, and echinoderms showed the opposite trend to polychaetes, and crustaceans showed poor tolerance to hypoxia. Based on the MDS analysis, the community composition of macrobenthos between hypoxic zone and non-hypoxic zone was significantly different. CCA analysis showed that community structure of macrobenthos was influenced by the bottom-water hypoxia in Yangtze Estuary during summer.