Since the last century, marine plastic debris, as a category of pollutants with potential ecological risks, have attracted the attention of researchers. As large as several meters or as small as a few microns, plastics are widely distributed in the marine environment. Compared with dissolved pollutants, it is more difficult for plastics to disperse evenly in marine media for they existed in solid form for a long time in marine environment. However, in recent years, plastic debris have been found in the ocean, polar and deep sea where are far from their sources, which is obviously closely related to the transport of plastics in the marine environment. On the one hand, the distribution and transport of plastics are affected by their material properties and various environmental factors. Therefore, it is necessary to understand and consider these factors in designation of marine plastic monitoring activities to improve effectively the sampling representativeness by adjusting and standardizing the sampling scheme. On the other hand, understanding the factors affecting the transport and fate of marine plastics is also a necessary prerequisite for predicting whether plastics will accumulate in specific sea areas or layers and where they would accumulate, for inferring the exposure of plastics in marine habitats, and then for predicting the potential risks of plastics to ecosystems and even human health. Base on relevant researches summarized on the transport behavior of plastics（including microplastics）, the factors affecting the horizontal and vertical distribution of marine plastics, and the sampling methods in plastic monitoring activities in seawater and sediments are discussed. According to the research progress related to plastic environmental behavior, the schematic basis and precautions during formulation of plastic debris monitoring activity are analyzed.
The fermentation product of a deep-sea-derived fungus Aspergillus puniceus A2 was isolated and purified with silica gel column and high-performance liquid chromatography, which isolated 6 compounds. The chemical structures of the 6 compounds were identified as Austocystin I（1）, Austocystin G（2）, 6-methoxyl Austocystin A（3）, Austocystin F（4）, F02ZA-1593B 2 （5）, and Austocystin A（6） by NMR spectrum analysis and compared with literature data. All the isolated compounds were reported firstly in this fungus. Among them, compounds 1, 2, 4 and 6 showed toxic effects on hepatic stellate cells LX2 at the concentration of 20 μmol/L, suggesting that they may have anti-hepatic fibrosis effects.Compounds 2, 3, 5 and 6 inhibited significantly the LPS-induced NO secretion in mouse monocyte macrophage RAW264.7 at 20 μmol/L, showing anti-inflammatory activity.
Tetrodotoxin（TTX） has an excellent application prospect in the treatment of neuropathic diseases such as sedation, analgesia, anesthesia and detoxification without causing addiction. However, due to its high cost of extraction from puffer fish, it is difficult to be widely applied. There is increasingly evidence that TTX originates from its symbiotic microbes. A strain of TTX-producing Bacillus sp. 3G2 was isolated from the liver of wild puffer fish（Takifugu oblongus）, and 35 ng/mL TTX in fermentation broth was detected by ELISA and colloidal gold assay. Then, Bacillus sp. 3G2 was inoculated in a special dialysis incubator, and continuous culture was achieved by continuous flow and fresh culture medium. The mice biological activity and tetrodotoxin test strips were used to detect TTX in the fermentation broth. The crude TTX was purified by TTX antibody immunoprecipitation and further identified by high performance liquid chromatography（HPLC）. Our study further corroborated the exogenous hypothesis of tetrodotoxin by means of screening high-quality strains from puffer fish, and preliminarily verify the superiority of dialysis production of tetrodotoxin. Therefor it provided a practical basis for subsequent commercial application.
The concept of standardization guideline for constructing a marine ecological monitoring station present in this paper is to accelerate the process of networking and standardization of long-term, fixed-point and continuous monitoring of marine ecosystem besides designation. Based on the analysis of status and experience of various long-term ecological monitoring networks home and abroad, the research status and existing problems of long-term positional monitoring of marine ecosystems in China were discussed, as well as the significance, principles and objectives of constructing marine ecological monitoring stations. In addition, guidelines of the principles, processes, construction contents and operational maintenance and management of the marine ecological monitoring stations were given. It is of great theoretical and practical significance in promoting the healthy and orderly development of marine ecological monitoring and its network system, enhancing the monitoring and early warning ability and research quality of marine ecosystems.
In order to develop the multi-trophic Integrated Aquaculture System（IMTA）, the composition and spatial characteristics of the annual changes of benthic macroalgae community in the intertidal zone of aquaculture sea area at Xiasanhengshan Island, Shengsi, Zhejiang Province in 2019, were investigated. Results showed that a total of 36 species, including 24, 4 and 8 species of Rhodophyta, Chlorophyta and Phaeophyta, were collected in the research area and the community structure changed significantly with seasons. Sargassum thunbergii, S. fusiforme, Ulva lactuca, Grateloupia turuturu and Laurencia composita dominated at all 9 sites in sea area investigated, and S. thunbergii was the dominant species occurred in all seasons. The annual averages of Margalef index（D）, Shannon index（H′） and Evenness index（J′） of the macroalgae are 0.81, 1.85 and 2.33, respectively, with obvious seasonal changes. The Pearson correlation analysis of dominant species showed that G. turuturu and L. composita had very significant correlations with chlorophyll a, temperature and salinity. The biomass of G. livida and Chondrus ocellatus correlated very significantly with dissolved oxygen. Corallina officinalis correlated significantly with dissolved inorganic phosphorus and pH, and S. horneri correlated significantly and inversely with temperature. U. lactuca correlated significantly with COD, pH, salinity and chlorophyll a. The biomass of S. fusiforme had a very significant correlation with chemical oxygen demand. The dominant species with commercial value of S. fusiforme, S. thunbergia and U. lactuca can be used as candidate species in the IMTA system. This study lays a theoretical foundation for the development and optimization of the fish-shell-algae integrated ecological aquaculture model in future.
The scleractinian corals in Weizhou Island, Guangxi province, are mostly located in the northernmost edge of global coral reef distribution, which has significant ecological and scientific values. However, coral reefs in Weizhou Island have declined yearly in recent 30 years and they are facing with the threat of biodiversity declination and malfunction island ecosystem, the feasibility assessment and restoration strategy were discussed according to the decision-making process. The results showed that there were 21 species of scleractinian corals belonging to 10 genera and 5 families. All six indicators of seawater quality fell into the class I by the water quality standard of China. The interannual variation of marine eutrophication index showed it was in the oligotrophic status. The coverage rate of macroalgae was less than 1.00%, and more than 90.00% of coral reef fish were omnivorous. The fish population structure was suitable for the diversity of macroalgae, which is proper for scleractinian corals growth. However, the average coverage rate of the scleractinian corals in this area was only 5.60%. It showed that 57.27% of the submarine bed covered with reef, 34.30% with unstable gravel and sand, and the regeneration of coral larvae was very slow with an average of 3.17 ind/m~2. The results indicate that Weizhou Island has a good potential for coral reef restoration, but the low coral coverage and low coral juvenile recruitment and unstable sediment structure are the main factors that limit the natural restoration. To establish the coral reef ecological restoration technology, a system of “juvenile coral breeding-coral cultivation in situ-artificial coral reef three-dimensional habitat construction” shall be established, That is on the premise of reducing the interference of human activities, the main artificial restoration strategies for the coral reef decline area in Weizhou Island should be to cultivate coral seedlings timely, plant batch coral in situ and build three-dimensional habitat landscape of artificial coral reefs.
In this study, a coupled model based on unstructured-grid, primitive-equation, Finite Volume Community Ocean Model（FVCOM）, the Mellor-Donelan-Oey（MDO） wave model and a stratified vegetation wave dissipation parameterization scheme is developed to study the mangrove wave attenuation capability. By comparing the scenarios with and without mangroves, the wave attenuation rate（A r ） is computed to study the wave attenuation capabilities of different mangrove morphologies under high and low water levels, and also to analyze the effect of plant density on their wave attenuation capabilities. It shows that A r is non-linearly and positively correlated with the width of the forests. The relationship between A r and water depth is related to the structure of mangroves. For A-type mangrove（e.g., Avicennia marina）, the maximum A r at low and high water level is 67.9% and 94.4%, respectively. The maximum A r of the B-type mangrove（e.g., Rhizophora stylosa） are 90.6% and 89.4% at low and high water-levels, respectively, while the WAR of the C-type mangrove（e.g., Ceriops tagal） is not significantly different at high and low water levels. The study also found that an increase in plant density can increase the upper limit of A r . It makes the A r more sensitive to the changes of forest width and the forest width is thus reduced to reach the maximum A r . The study shows that the performances of wave attenuation by different mangrove morphologies should be considered in the conservation of mangrove ecosystems.
Hong Kong oyster（Magallana hongkongensis） is an important economic shellfish cultivated in the coastal areas of southern China. However, breeding diseases frequently happen during cultivation, and they have seriously restricted the sustainable development of Hong Kong oyster farming industry. As an important regulatory factor, microRNA（miRNA） participates in various biological processes of marine species through post-transcriptional regulation of their target genes. In this study, we used high-throughput sequencing technology to create miRNA libraries from gill of Hong Kong oyster under different induction time points of Vibrio parahaemolyticus infection and then explored the miRNAs related to immune regulation via bioinformatics analysis. In total, we obtained 453 conserved miRNAs and 222 novel miRNAs. Subsequently, the unique miRNAs among blank control group/12 h pathogen-injection group, blank control group/24 h pathogen-injection group, 12 h pathogen-injection group/24 h pathogen-injection group were further screened. As result, a number of differentially expressed or highly expressed miRNAs were found in different comparison groups. Among them, miR-10, miR-23, miR-92, miR-100, miR-125, miR-144, miR-145, miR-146, miR-335 and miR-750 have been verified to involve in the immune regulation processes in a variety of marine animals. KEGG enrichment analyses of target genes of differentially expressed miRNAs showed that the target genes of miR-411-5p, miR-4454-5p, novel-m0159-3p and novel-m0187-3p participated in immune-related pathways. These results indicated that the above-mentioned miRNAs may play an important role in the immune regulation of Hong Kong oysters, Thus, it is necessary to further explore on them.
In this paper, total organic carbon analyzer coupled with stable isotope mass spectrometer（TOC-IRMS）technology is used to study carbon isotope composition and dissolved organic carbon（DOC） in water using high temperature oxidation method. According to the composition characteristics of DOC, five water soluble compounds, namely caffeine, glucose, phthalic acid, potassium acetate and sodium humate, are selected from the aspects of oxidation in order of difficulty and molecular structure to prepare DOC solutions. By changing the experimental parameters, such as solution carbon concentration, oxidation tube temperature, oxygen admission time and carrier gas flow rate, the effect of different experimental conditions on the carbon conversion rate and isotope fractionation of five compounds are studied. The parameters of TOC-IRMS are set for oxidation temperature at 850 ℃, the oxygen supply time at 20 s（flow rate at 10 cm~3/min）, and the carrier gas flow rate at 80 cm~3/min. The measured average carbon conversion rate of DOC solutions of five compounds in different concentrations is between 95.69%～103.57%, the δ 13 C are basically consistent with the calibration reference values, and the difference range is between-0.82‰～0.55‰. Under the experimental conditions, the relative standard deviation of DOC content in different types of water samples is less than 3.7%, the standard deviation of δ 13 C value is less than 0.2‰. Results show that the data obtained by TOC-IRMS online high-temperature oxidation method met the accuracy requirements.
Based on the environmental survey data from the Pearl River Estuary（PRE） in April（spring） and October（autumn） 2020, the pressure-state-response（PSR） model evaluation, the principal component analysis and the correlation analysis were used to evaluate eutrophication status and the environmental factors in the PRE. Results showed that the PSR comprehensive evaluation for the PRE grade was Moderate-Poor, among the five, “Superior, Superior-Moderate, Moderate, Moderate-Poor and Poor”, and it fluctuated insignificantly in recent years. The primary factors affecting the PRE eutrophication were organic pollutants and nutrients and the secondary factors are chlorophyll and dissolved oxygen. The nutrients were negatively correlated with salinity and positively correlated with chlorophyll in water. Eutrophication in the PRE was mainly caused by terrestrial discharges from the city surrounding areas and the water mixed nutrients and phytoplankton activities had affected the eutrophication status of the PRE.
The spatiotemporal variations of temperature inversion in the Gulf of Alaska（GOA） are analyzed based on 2002-2020 Argo data and relationship between its interannual variations and vertical potential temperature anomaly also is investigated. The results show that there are considerable spatiotemporal variations of temperature inversion. Spatially, temperature difference（ΔT） is the largest, moderate and the weakest in the northern GOA（NGOA）, southeastern GOA（SEGOA） and southwest（SWGOA）, respectively. The inversion thickness（ΔD） is the thickest in the SWGOA, relatively thinner in the NGOA and thinnest in the SEGOA. As for seasonal change, ΔT and ΔD in the NGOA change apparently with the largest ΔT and ΔD in winter, then they decrease because of seasonal heating and vertical mixing. In the SEGOA, ΔT peaks in March（0.46 ℃） and September（0.40 ℃）. There has a ΔD maximum（44 m） in winter and a ΔD minimum（only 23 m） in autumn. In the SWGOA, ΔT changes with seasonal alternations in 0.24-0.33 ℃ producing two peaks 0.31 and 0.33 ℃ in April and October, respectively. ΔD is larger than 100 m in winter and is the thinnest about 57 m in autumn. At interannual time scales, ΔT displayed positive anomalies in 2002, 2007-2009, 2012 and 2017, but negative anomalies in 2003-2005, 2010, 2013-2016 and 2018-2020. ΔD is mainly thicker than normal in 2002, 2007-2008, 2012 and 2017-2020, while thinner than normal in 2003-2006 and 2015-2016. The interannual variations of ΔT and ΔD in the NGOA and SEGOA are well consistent with each other, but there is no clear connection between them in the SWGOA. Moreover, ΔT and ΔDchanges are closely related to vertical potential temperature anomaly. When the vertical potential temperature of seawater was in cold（warm） anomaly, ΔT revealed a positive（negative） anomaly in the whole GOA, ΔD tended to be thicker（thinner） in the NGOA and SEGOA, but thinner（thicker） in the SWGOA.
The oil leakages on the coastal zone will form a pollution source area endangering the ecological environment for a long time. Under the multi-influences of hydrodynamics, microorganisms and geochemistry, the reducing processes of mass, concentration, volume, toxicity and fluidity of petroleum pollutants are called natural attenuation. This paper systematically reviews the natural attenuation characteristics and research methods of oil pollutants in coastal areas, and clarifies the influences of oil properties, sediment types, hydrodynamic factors, photooxidation reactions and microorganisms on the natural attenuation of coastal oil pollution source areas. The characteristic factors of the natural attenuation process in the source area, such as geochemistry, microbes and geophysics are summarized. At the same time, the prediction methods of the natural attenuation process, the key and aporia of multidisciplinary and multi-data-driven researches are put forward. Besides the study of natural attenuation in the source areas of coastal oil pollution.
In this paper, the mesoscale eddies in the Northwest Pacific Ocean（0°—45°N, 120°—180°E） are automatically identified and followed by the method of OW parameter and closed curve. The seasonal variation, interannual variation, quantitative characteristics and geometric parameters of mesoscale eddies with different lifetime are analyzed. It is found that the peak of the number of short lifetime（15-30 days） and medium lifetime（30-105 days） mesoscale eddies is about 2-3 months later than the cold peak of the meteorological season. Different from other lifetime mesoscale eddies, for the medium lifetime mesoscale eddies, cyclonic eddies（33.9 cm/s） rotates faster than the anticyclonic eddies（16.9 cm/s）, and medium lifetime mesoscale eddies’ seasonal variation is the most significant. Winter is more suitable for the occurrence and development of mesoscale eddies in the Northwest Pacific Ocean, and in terms of lifetime, it is more likely to develop into medium lifetime eddies. There are three obvious periodic changes（the first main cycle, the second main cycle and the third main cycle） in the monthly number changes in mesoscale eddies of different lifetimes. According to the time scale of different main cycles, their influencing factors may be sunspot activity, ENSO phenomenon and seasonal variation respectively. In terms of geographical distribution, the distribution of high frequency of mesoscale eddies with different lifetimes is not completely consistent. In terms of eddy’s amplitude, the medium lifetime mesoscale eddies have the largest amplitude（15-25 cm）, followed by the short lifetime mesoscale eddies（15-20 cm）, and the long lifetime mesoscale eddies has the smallest amplitude（10-16 cm）. In terms of eddy’s radius, the average radius of long lifetime mesoscale eddies is bigger（20-30 km） only in the subtropical countercurrent area, whereas the average radius of medium and short lifetime mesoscale eddies is bigger（30-45 km） in the north of the study area. From the geometric parameters, the mesoscale eddies’ geometric parameter of Northwest Pacific Ocean is not the biggest in the middle of life. It reaches its first high value about the first third of its life, and then fell slightly, maintaining a stable value, until it rises slightly to the second high value in the last third of life, and then fell rapidly to zero.
Microorganisms in glacial soil are a key component of the cryosphere. Surrounded by the ocean the substance transportations and factors adjacent the Antarctic Nelson Glacier alter or disturb the physicochemical properties of inshore soil, thus affecting the microbial communities in the soil. In this study, soil samples were collected from different distances offshore Nelson Glacier. Then 16S rDNA V4 region amplified sequencing of bacteria and archaea and metagenomic sequencing were performed to investigate the microbial community structure and metabolic potential in glacial soil in different distances from the shore. Results of species diversity analysis showed that the composition of soil microbial communities varied among loci. However, Proteobacteria, Actinobacteria, and Bacteroidetes were commonly present in glacial soil samples with relative high abundance. The results of the metagenomic analysis showed that the distribution of functional genes in microbial communities in glacial soil differed distantly toward the open sea and the gene abundances functioning metabolic pathways such as energy metabolism and transmembrane transport decreased as the sites moved offshore. Carbon, nitrogen, and sulfur metabolism in glacial soil were dominated by the reductive citrate cycle, denitrification and assimilative sulfate reduction pathways, respectively, among which the denitrification pathway genes reached the highest abundance in all samples. The metagenome-assembled genome bin＿71 containing the denitrification functional gene was obtained by binning and the core metabolic pathways were reconstructed. This study reveals primarily the community structure and metabolic potential of microorganisms in the soil of Antarctic Nelson glacier, which provides basic data for subsequent discovery of new species and functional genes in the Antarctic glacier soil. Also it explores the impact of the ocean on coastal ecosy-stems under global warming.
It was recognised that the wind usually affects the ocean surface produces deep ocean ambient noise higher than 200 Hz. However, some studies showed that standing waves generated by wind causing ocean surface wave interactions nonlinearly. It can resonate with the sea floor to form seafloor microseisms, resulting in noise below 10 Hz. at this paper, very low frequency noise below 10 Hz at Wake Island is studied for this new wind noise mechanism. The marine environments under different frequency noise spectrum correlation with wind speed, the influence of wind speed and wind direction on the signal of the second group of hydrophone triplet set up at the south and north of Wake Island were compared. Results showed that the ocean ambient noise level had the best correlation with the wind speed at 2 Hz, and the change of wind speed and direction showed a better affection on the spectrum density of ocean ambient at very low frequency noise. Finally, the fitting curve of the hydrophone triplet 2 Hz ocean ambient noise level and wind speed is given, and the cross-correlation coefficients of the fitting curves are all higher than 0.99.
Based on the long-term continuous hydro-meteorological data from buoys and tidal gauge stations in the upper Pearl River Estuary near Guangzhou, the hydro-meteorological characteristics of this region during the Typhoons Hato and Mangkhut are analyzed, and the dynamic factors causing the marine disasters are also discussed. Results show that firstly influenced by typhoon the wind speed of each station increased from Level 1-4 to 7-8, and the wind speed reached the maximum around 6-7 hours influenced by Typhoon Level 7 wind circle. The tide levels of all station are above the red warning tide level. The maximum storm surge is approximately 2-3 meters. The wave height increased from Level 1-2 to 3-4. The residual current decreased before it increased. The lowest value of the residual current appeared on the day of the typhoon landfall and the typhoon changes the direction of the residual current. The sea surface temperature dropped by 1-2 ℃ and the sea surface salinity increased by 4-12. Secondly, the first response to the typhoon were wind and residual current. The maximum wave height appeared about 1 hour later than the maximum wind speed. The highest tide level appeared in about 1-2 hours later than the typhoon landfall. The changes in sea surface temperature and salinity came later than the wind in about 5-6 hours. Thirdly, the typhoon wind circle radius, the duration of the severe typhoon, typhoon intensity and the moving speed had a great influence on storm surge and wave disaster. The wave height increased sharply and it also had a great influence on the storm surge with correlation coefficient of about 0.7. Fourthly, the landing position of Mangkhut was 74 km farther than Hato, and it was not in the astronomical spring tide period, but the level 7 wind circle radius was 130 km larger than that of Hato. The duration of the severe typhoon was 27 hours longer than that of Hato, so the marine disaster caused by Mangkhut was stronger than Hato. Also, the maximum storm surge was 30-50 cm higher than that of Hato. The Level II storm surge lasted 2.5 hours longer than Hato, and the moderate wave lasted 11 hours longer than that of Hato.
After 30 years reclamations on the sea beach in Shenzhen Bay the beach development is retarding under natural conditions due to the weakening dynamic changes along the coast areas. In perspective of high-quality recreational space, tourism values and the coast protection, the beach areas are urgently needed in Shenzhen Bay. In order to strengthen the relation between human and the sea for the vitality of Shenzhen Bay, it is necessary to establish an urban natural buffer zone and ward off the threat of extreme storms in view of coastal protection and entertainments of residents. Therefore, we select a coastal area more suitable for beach nourishment in Shenzhen Bay based on natural attributes of near shore marine elements and social attributes such as marine development activities for verification with numerical models. The coastal marine elements considered in the beach restoration include waves, tidal currents, topographic features, sediments, etc. The numerical models used include velocity change, wave and long-term spatiotemporal evolution of the beach. This paper provides demonstration and reference for the site selection of beach nourishment and the restoration scheme of artificial beach in coastline where much dynamic change occurred and was unable to develop under natural conditions.
C-type lectin is the main member of the lectin family, which has abundant diversity in invertebrates. Their unique biological functions are widely applied in many fields, such as biology, medicine and so on. In this study, a novel C-type lectin RPCL was cloned from Ridgeia piscesae, a tube worm collected from the deep-sea hydrothermal region at Juan de Fuca Ridge in the northeast Pacific Ocean. The similarity between this gene and the reported lectins is very low, and the predicted 3D structure was quite different from the known lectins, suggesting that it may have some special properties. Furthermore, the heterologous recombinant expression of RPCL was successfully achieved, and a large amount of soluble proteins were obtained through purification and renaturation. It will facilitate the further study on the function of RPCL.
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本研究于2020年7月在大亚湾及大鹏半岛沿岸开展造礁石珊瑚的分布、覆盖率、死亡率、硬珊瑚补充量和物种多样性调查.结果表明:24个站位共发现造礁石珊瑚9科17属44种以及5个未定种,其中裸肋珊瑚科的种类最多,有7属27种,其次为鹿角珊瑚科和滨珊瑚科,均有2属6种;中央列岛沿岸造礁石珊瑚平均覆盖率为12.0％,三门岛沿岸平均覆盖率为12.9％,大鹏半岛沿岸平均覆盖率为5.2％;以坚实滨珊瑚(Porites solida)、翼形蔷薇珊瑚(Montipora peltiformis)、五边角蜂巢珊瑚(Favites pentagona)和多孔同星珊瑚(Plesiastrea versipora)等为优势种;造礁石珊瑚物种多样性较高.与历史数据相比,大亚湾及大鹏半岛沿岸造礁石珊瑚退化严重,活珊瑚覆盖率锐减,优势种由分支状珊瑚逐步转变为皮壳状或亚团块状珊瑚.此外,本研究构建了近岸造礁石珊瑚生态脆弱性评价体系,并对目前大亚湾及大鹏半岛沿岸造礁石珊瑚进行了生态脆弱性评价.结果显示,中央列岛、三门岛和大鹏半岛东侧海域造礁石珊瑚处于低或中脆弱状态;较场尾、杨梅坑、西冲和大鹏半岛西侧海域造礁石珊瑚处于高或很高脆弱状态,在环境压力影响下其受损可能性较高.在海水养殖、渔业捕捞、滨海旅游和船舶航行等日益频繁的人类活动下,大亚湾及大鹏半岛沿岸造礁石珊瑚整体处于中高脆弱状态,建议加强珊瑚礁监测,并采取相应的保护措施.
