UAV marine monitoring plays an essential role in marine environmental protection because of its flexibility and convenience,low cost and convenient maintenance.In marine environmental monitoring,the similarity between...UAV marine monitoring plays an essential role in marine environmental protection because of its flexibility and convenience,low cost and convenient maintenance.In marine environmental monitoring,the similarity between objects such as oil spill and sea surface,Spartina alterniflora and algae is high,and the effect of the general segmentation algorithm is poor,which brings new challenges to the segmentation of UAV marine images.Panoramic segmentation can do object detection and semantic segmentation at the same time,which can well solve the polymorphism problem of objects in UAV ocean images.Currently,there are few studies on UAV marine image recognition with panoptic segmentation.In addition,there are no publicly available panoptic segmentation datasets for UAV images.In this work,we collect and annotate UAV images to form a panoptic segmentation UAV dataset named UAV-OUC-SEG and propose a panoptic segmentation method named PanopticUAV.First,to deal with the large intraclass variability in scale,deformable convolution and CBAM attention mechanism are employed in the backbone to obtain more accurate features.Second,due to the complexity and diversity of marine images,boundary masks by the Laplacian operator equation from the ground truth are merged into feature maps to improve boundary segmentation precision.Experiments demonstrate the advantages of PanopticUAV beyond the most other advanced approaches on the UAV-OUC-SEG dataset.展开更多
Deoxygenation has frequently appeared in coastal ecosystems over the past century due to the joint infl uence of increasing anthropogenically induced nutrient inputs and global warming.The semi-enclosed Bohai Sea is a...Deoxygenation has frequently appeared in coastal ecosystems over the past century due to the joint infl uence of increasing anthropogenically induced nutrient inputs and global warming.The semi-enclosed Bohai Sea is a typical system that is prone to deoxygenation,with regular hypoxia events consistently recorded in recent decades.Based on in-situ observation data collected in large-scale voyage surveys in the Bohai Sea during 2008-2017,the seasonal variability in dissolved oxygen(DO)and its controlling mechanisms were studied.The results indicated that in spring and autumn,the DO distributions exhibited similar spatial patterns in the surface and bottom layers,while in summer,its spatial distribution was characterized by large-scale oxygen-poor zones distributed off the Qinhuangdao Coast and the central southern Bohai Sea in the bottom layer.The controlling mechanisms of the DO distribution varied from season to season.Spring and autumn DO distributions were dominated by the seawater temperature.Under the combined eff ects of stratifi cation and decomposition,the summer bottom DO exhibited dual-core distribution.On the one hand,stratifi cation could greatly impede vertical mixing,resulting in reduced bottom DO replenishment.On the other hand,the increased bottom organic matter intensifi ed the decomposition processes,inducing massive DO consumption and elevated dissolved inorganic nitrogen concentrations.In addition,the stronger stratifi cation might be the reason for the more severe deoxygenation in the southern oxygen-poor zones in summer.Our study provides guidance for an in-depth understanding of the DO seasonality in the Bohai Sea and the mechanisms that modulate it and for the improvement of hypoxia forecasts in ocean models.展开更多
Based on the concentrations of the trace elements,rare earth elements(REE),and Sr isotopic compositions in reef carbonates from the well‘Xike-1’reef core of the Xisha Islands,the constraints on sediment provenance a...Based on the concentrations of the trace elements,rare earth elements(REE),and Sr isotopic compositions in reef carbonates from the well‘Xike-1’reef core of the Xisha Islands,the constraints on sediment provenance and paleoenvironment were defined.Variations of the terrigenous input into the paleoseawater were traced in detail and the paleoenvironment and sediment provenance were further investigated.The results show that the HREE/LREE values in the reef carbonates are negatively associated with their Th and Al concentrations;however,their Al and Th concentrations show positive correlation.The lowest 87 Sr/86 Sr values in the reef carbonates generally coincide with the lowest values of Al,Th concentrations and the highest values of HREE/LREE.These data indicate that the HREE/LREE,Al concentrations,and Th concentrations of the reef carbonates are useful indexes for evaluating the influence of the terrigenous inputs on the seawater composition in the study area.From top to bottom,the changing process of the HREE/LREE values and Al,Th concentrations can be divided into 6 intervals;they are H1(0–89.30 m,about 0–0.11 Myr),L1(89.30–198.30 m,about 0.11–2.2 Myr),H2(198.30–374.95 m,about 2.2–5.3 Myr),D(374.95–758.40 m,about 5.3–13.6 Myr),L2(758.40–976.86 m,about 13.6–15.5 Myr),and H3(976.86–1200.00 m,about 15.5–21.5 Myr).Moreover,the changing trend of the HREE/LREE values coincides with that of the seawater δ^13C values recorded by benthonic foraminiferal skeletons from the drill core of ODP site 1148 in the South China Sea(SCS),but not with that of the seawaterδ18O values.The high uplifting rates of the Qinghai-Tibet Plateau coincide with the high Th and Al concentrations and the low HREE/LREE values in the reef carbonates.These data indicate that the main factors controlling the changes of terrigenous flux in the SCS are the tectonic activities associated with Qinghai-Tibet Plateau uplifting and the variations of uplifting rates rather than paleoclimatic changes.展开更多
Colored dissolved organic matter(CDOM)is a crucial constituent that affects the optical absorption properties of seawater.Owing to the relatively limited measured data on the spatial distribution characteristics of CD...Colored dissolved organic matter(CDOM)is a crucial constituent that affects the optical absorption properties of seawater.Owing to the relatively limited measured data on the spatial distribution characteristics of CDOM in the tropical eastern Indian Ocean,this study analyzes the optical absorption characteristics of CDOM in the southeast Indian Ocean using the data collected during four seasons from 2013 to 2017.This work also systematically describes the seasonal horizontal and vertical distribution characteristics of CDOM in this area and conducts a preliminary analysis of the relevant factors affecting CDOM absorption characteristics in this region.Results indicate that the CDOM ag(440)during summer was remarkably lower than that in the coastal waters of Europe and coastal waters of China but slightly higher than that in the western and southeast Pacific.The spatial distribution of surface CDOM shows remarkable seasonal differences,and the spatial distribution characteristics of CDOM in the 5°S,92°E region differ between spring/summer and autumn/winter.The values of ag(400)and ag(440)are weak/strong at a surface/subsurface level of 100 m,with differences found between summer and winter.The correlation of CDOM with temperature,salinity,and chlorophyll-a concentration is relatively low,indicating that CDOM is an independent driving mechanism influenced by phytoplankton degradation,photobleaching,and water mixing.展开更多
As an important land-ocean interaction process,submarine groundwater discharge(SGD)is composed of multiple dynamical processes at different scales and plays an important role in the study of coastal ocean geochemical ...As an important land-ocean interaction process,submarine groundwater discharge(SGD)is composed of multiple dynamical processes at different scales and plays an important role in the study of coastal ocean geochemical budgets.However,most of the existing studies focus on the quantification of the total groundwater discharge,few studies are about the differentiation and quantification of groundwater discharge processes at different scales(i.e.,short-scale SGD and long-scale SGD).As a world-class river,the Huanghe River is highly turbid and heavily regulated by humans.These natural and anthropogenic factors have a significant impact on groundwater discharge processes in the Huanghe River Estuary(HRE).In this study,the distribution patterns of the natural geochemical tracer radium isotopes(^(224)Ra and^(223)Ra)and other hydrological parameters in the HRE were investigated during four cruises.By solving the mass balance of^(224)Ra and^(223)Ra in the HRE,the long-scale SGD flux was quantified as 0.01−0.19 m/d,and the short-scale SGD flux was 0.03−0.04 m/d.The rate of short-scale SGD remained essentially constant among seasons,while the rate of long-scale SGD varied considerably at different periods and showed a synchronous trend with the variation of river discharge.The results of this study are significant for understanding the SGD dynamics in the HRE and the contribution of SGD to the ocean geochemical budgets.展开更多
Natural radionuclides are powerful tools for understanding the sources and fate of suspended particulate matter(SPM).Particulate matter with different particle sizes behaves differently with respect to adsorption and ...Natural radionuclides are powerful tools for understanding the sources and fate of suspended particulate matter(SPM).Particulate matter with different particle sizes behaves differently with respect to adsorption and desorption.We analyzed the activi-ties and distribution characteristics of multiple natural radionuclides(238U,226Ra,40K,228Ra,7Be and 210Pbex)on size-fractionated SPM at the Lijin Hydrographic Station(Huanghe or Yellow River)every month over a one-year period.Results showed that medium silt(16–32µm)was the main component.As expected,the activity of each radionuclide decreased with an increase of particle size.We examined the sources of SPM with different particle sizes using activity ratios of 226Ra/238U,228Ra/226Ra,40K/238U and 7Be/210Pbex,and concluded that SPM with different particle sizes originated from different sources.Our results indicate that fine SPM(<32µm)was mainly from the erosion of soil along the lower reaches of the Yellow River,while coarse SPM(>32µm)was mainly derived from resuspension of riverbed sediment.During high runoff periods,the concentration of SPM increased significantly,and the pro-portion of fine particles originating upstream increased.Naturally occurring radioactive isotopes,especially on size-fractionated par-ticles,are therefore seen as useful tracers to understand the sources and behaviors of riverine particles transported from land to sea.展开更多
As a river with more than 3000 reservoirs in its watershed,the Yellow River has been affected by dams not only on the sediment load,but also on the water quality.Water-sediment regulation scheme(WSRS),which has been c...As a river with more than 3000 reservoirs in its watershed,the Yellow River has been affected by dams not only on the sediment load,but also on the water quality.Water-sediment regulation scheme(WSRS),which has been carried out annually in the Yellow River since 2002,is a typical human activity affecting river water quality.Chromophoric dissolved organic matter(CDOM)in river is susceptible to changes in ecological and environmental conditions as well as human activities.Here,we report variations in dissolved organic carbon concentrations,compositions and sources of CDOM in time series samples in the lower Yellow River during WSRS.In addition,a parallel factor fluorescence analysis(PARAFAC)method is applied to identify different fluorescent components in water samples during WRSR,showing four major components including tryptophan-like component(C1),microbial humic-like component(C2),terrestrial humic-like component(C3)and tyrosine-like component(C4).In general,C1 increased after water regulation,while C2 and C3 increased after sediment regulation,indicating that the water and sediment released by the dam have different effects on CDOM compositions.Under the impacts of the dam,source of CDOM in the lower Yellow River is mainly autochthonous related to microbial activities,and is regulated by the terrestrial input during WSRS period.Sediment resuspension inhibits microbial activities and reduces the production of autochthonous CDOM.Overall,human activities especially WSRS,as exemplified here,significantly alter the quality and quantity of CDOM in the lower Yellow River,affecting CDOM dynamics and biogeochemical processes in the estuarine environment.展开更多
Based on research results on the impacts of solar light,seawater temperature,and nutrient available to phytoplankton growth and changes in phytoplankton physiology and assemblage,we discussed the order of influence of...Based on research results on the impacts of solar light,seawater temperature,and nutrient available to phytoplankton growth and changes in phytoplankton physiology and assemblage,we discussed the order of influence of these factors.By clarifying the mechanisms and processes of the impacts by these factors,we have determined the rising order of the importance as solar light,seawater temperature,and nutrient silicon (Si).Therefore,for human interests in sustaining economic development,the first thing to be considered is the input of nutrient Si into the ocean,followed by seawater temperature change.展开更多
In recent years,oil spill accidents occur frequently in the marine area of China.Finding out the spilled oil source is a key step in the relevant investigation.In this paper,a step-by-step fingerprinting identificatio...In recent years,oil spill accidents occur frequently in the marine area of China.Finding out the spilled oil source is a key step in the relevant investigation.In this paper,a step-by-step fingerprinting identification method was used in a spilled oil accident in the Bohai Sea in 2002.Advanced chemical fingerprinting and data interpretation techniques were used to characterize the chemical composition and determine the possible sources of two spilled oil samples.The original gas chromatography -flame ionization detec-tion (GC-FID) chromatogram of saturated hydrocarbons was compared.The gas chromatography-mass spectrometry (GC/MS) chromatograms of aromatic hydrocarbons terpane and sterane,n-alkane and poly-aromatic hydrocarbons (PAHs) were analyzed.The correlation analysis on diagnostic ratios was performed with Student’s t-test.It is found that the oil fingerprinting of the spilled oil (designated as sz1) from the polluted sand beach was identical with the suspected oil (designated as ky1) from a nearby crude oil refinery factory.They both showed the fingerprinting character of mixed oil.The oil fingerprinting of the spilled oil (designated as ms1) collected from the port was significantly different from oil ky1 and oil sz1 and was with a lubricating oil fingerprint character.The identification result not only gave support for the spilled oil investigation,but also served as an example for studying spilled oil accidents.展开更多
Immunostimulants may improve disease resistance of aquaculture animals by promoting the nonspecific immunity response of the organisms. Five types of saccharides, including chitosan, yeast polysaccharide, burdock olig...Immunostimulants may improve disease resistance of aquaculture animals by promoting the nonspecific immunity response of the organisms. Five types of saccharides, including chitosan, yeast polysaccharide, burdock oligosaccharide, seaweed polysaccharide and lentinus edodes polysaccharide, were screened for potential use as immunostimulants by using spectrophotometry. The saccharides were injected into Apostichopus japonicus, a sea cucumber, and the lysozyme and superoxide dismutase (SOD) activities of the coelomic fluid and epidermal slime were monitored in six consecutive days. The results show that the lysozyme activity of the animal’s coelomic fluid was significantly stimulated on day 2, day 4 and day 6 after the injection of the saccharides (P<0.05). The effects of chitosan and yeast polysaccharide were the most notable. The lysozyme activity of the epidermal slime was significantly increased by chitosana, yeast polysaccharide, seaweed polysaccharide, and burdock oligosaccharide on day 1 and day 2 after the injection (P<0.05). The SOD activity of the coelomic fluid was significantly promoted by the saccharides on day 2 and day 4 post-injection (P<0.05), while the SOD activity of the epidermal slime increased on day 2. These findings indicate that chitosan and yeast polysaccharide are the most effective immunostimulants and potential healthy anti-disease feedstuff for A. japonicus.展开更多
The classification and identification for Protoperidinium species are the most difficult work during its taxonomic study. In this research, taxonomic status of Protoperidinium was clarified by tracing its taxonomic hi...The classification and identification for Protoperidinium species are the most difficult work during its taxonomic study. In this research, taxonomic status of Protoperidinium was clarified by tracing its taxonomic history, 23 species belong to genus Protoperidinium on the coasts of China were preliminarily identified, and morphological description and plate patterns were given for each species. The key differences of similar species were also discussed in this study, we believe that P. oceanicum and P. murry, P. tumidum and P. fatulipes, P. globules and P.majus are separate species; P. diabolum should be treated as the valid name instead of the reported names Peridinium globosum or Peridinium longipes; the taxonomic relationship between P. punctulatum and P.subinerme requires further study.展开更多
Statistical analysis on data collected in the Jiaozhou Bay (Shandong, China) from May 1991 to February 1994 and those collected in Hawaii from March 1958 to December 2007 shows dynamic and cyclic changes in atmospheri...Statistical analysis on data collected in the Jiaozhou Bay (Shandong, China) from May 1991 to February 1994 and those collected in Hawaii from March 1958 to December 2007 shows dynamic and cyclic changes in atmospheric carbon in the Northern Pacific Ocean (NPO), as well as the variation in space-time distribution of phytoplankton primary production and atmospheric carbon in the study regions. The study indicates that the human beings have imposed an important impact on the changing trends of the atmospheric carbon. Primary production in the Jiaozhou Bay presents a good example in this regard. In this paper, dynamic models of the atmospheric carbon in the NPO, the cyclic variations in the atmospheric carbon, and primary production in the Jiaozhou Bay are studied with simulation curves presented. A set of equations were established that able to calculate the rate and acceleration of increasing carbon discharged anthropologically into the atmosphere and the conversion rate of phytoplankton to atmospheric carbon. Our calculation shows that the amount of atmospheric carbon absorbed by one unit of primary production in the Jiaozhou Bay is (3.21–9.74)×10-9/(mgC·m-2d-1), and the amount of primary production consumed by a unit of atmospheric carbon is 102.66–311.52 (mgC·m-2d-1/10-6). Therefore, we consider that the variation of atmospheric carbon is a dynamic process controlled by the increase of carbon compound and its cyclic variation, and those from anthropologic discharge, and phytoplankton growth.展开更多
Desertification has been notably expanding in China in the recent decade, especially in North China where dust/sand storm (DSS) frequently assaulted local communities. Analyses in marine ecology found that the earth e...Desertification has been notably expanding in China in the recent decade, especially in North China where dust/sand storm (DSS) frequently assaulted local communities. Analyses in marine ecology found that the earth ecosystem could be able to complement nutrient silicon for keeping sustain- able development of marine ecosystem, and decreasing CO2 concentration in the atmosphere; as a result, the area of desertification would be enlarged. Modern human being activities have resulted in constant changes in the amount of silicon transport from land into sea, leading to oversupply of nitrogen and phosphorus but silicon in seawater. The proportion of nitrogen, phosphorus and silicon was seriously im- balanced and the limitation of silicon for phytoplankton growth has become more serious. The silicon de- ficiency has damaged the marine ecosystem in coastal regions and slowed down the carbon sedimentation in the atmosphere of the world. The authors believe that the continual discharge of CO2 into the atmos- phere is the cause for the global warming including marine water temperature rise. Consequently, the earth ecosystem would have to trigger its complementary action to resume to the silicon balance by algae bloom in seawater for reducing air and water temperatures. In order to complement nutrient silicon into the sea, the ecosystem would transport silicon via the atmosphere; therefore, the desertification in the in- ner land is a natural reaction. As marine phytoplankton booming can reduce the CO2 concentration in the atmosphere and further ease the green-house effect, during this process, a large amount of silicon are de- manded by the ecosystem, which human being are unable to stop desertification from happening but slow down the progress and ease the risk. Therefore, as an important role in earth ecosystem, people should reduce the CO2 discharge into the atmosphere first; then, the normal function of river transporting silicon must be restored. In this way, the CO2 in the atmosphere can be kept in balance, the global warming slowed down, marine ecosystem development sustained, the drought in inner land eased, and the desert gradually under-controlled.展开更多
Changes in the marine productivity and sedimentary environment since the last deglaciation in the Ross Sea are presented in this paper.Opal has replaced calcium carbonate as the major biogenic component and has a sign...Changes in the marine productivity and sedimentary environment since the last deglaciation in the Ross Sea are presented in this paper.Opal has replaced calcium carbonate as the major biogenic component and has a significantly positive correlation with total organic carbon(TOC),which indicates that siliceous phytoplankton controlled the absorption and release of carbon by the biological pump and was the main producer of marine organic matter.Using the AMS 14C age framework,foraminiferal fossils and redox sensitive elements(RSEs),we found that both the sedimentary environment and marine productivity changed clearly in^11 cal ka BP,which is more likely related with the melting and retreat of the Ross Ice Shelf.In addition,the increase of marine productivity promoted the sinking of more organic-matter to the seabed.A large proportion of oxygen in the bottom water body was consumed and more carbon dioxide was produced during the decomposition of organic matter,making the bottom water body more soluble to calcium carbonate.展开更多
The large-scale green tide caused by Ulva has occurred successively in the Yellow Sea since 2007,and new events of green tide also continued to appear in nearby sea areas,indicating an undergoing rapid development of ...The large-scale green tide caused by Ulva has occurred successively in the Yellow Sea since 2007,and new events of green tide also continued to appear in nearby sea areas,indicating an undergoing rapid development of occurrence patterns for harmful macroalgal blooms(HMBs)along coastal China.In August 2021,a green tide occurred for the first time in Bayuquan sea area of Yingkou city,Liaoning Province in the Bohai Sea.In this study,morphological and molecular approaches were used to identify the causative species as U.meridionalis,an alien subtropical alga previously found to dominate green tides in the South China Sea.According to the hydrological data of Bayuquan in summer 2021,combined with morphological and developmental observations for this alga,we hypothesized that the disturbance caused by the typhoon In-Fa might have detached the local U.meridionalis from substrates,especially for those thalli with poorly developed holdfasts,and the ensuing wave-free period with unusually high temperature,which fell in the reported optimum growth temperature for U.meridionalis,might have provided the favorable conditions for the final bloom of the floating seaweeds.This is the first report on the bloom of subtropical U.meridionalis in the north temperate sea zone,indicating that the ecological risk of causing green tides in the future by this rapidly spreading species deserves high attention.展开更多
Ecological protection and high-quality development of the Yellow River basin are becoming part of the national strategy in recent years.The Yellow River Estuary has been seriously affected by human activities.Especial...Ecological protection and high-quality development of the Yellow River basin are becoming part of the national strategy in recent years.The Yellow River Estuary has been seriously affected by human activities.Especially,it has been severely polluted by the nitrogen and phosphorus from land sources,which have caused serious eutrophication and harmful algal blooms.Nutrient criteria,however,was not developed for the Yellow River Estuary,which hindered nutrient management measures and eutrophication risk assessment in this key ecological function zone of China.Based on field data during 2004-2019,we adopted the frequency distribution method,correlation analysis,Linear Regression Model(LRM),Classification and Regression Tree(CART)and Nonparametric Changepoint Analysis(nCPA)methods to establish the nutrient criteria for the adjacent waters of Yellow River Estuary.The water quality criteria of dissolved inorganic nitrogen(DIN)and soluble reactive phosphorus(SRP)are recommended as 244.0μg L^(−1) and 22.4μg L^(−1),respectively.It is hoped that the results will provide scientific basis for the formulation of nutrient standards in this important estuary of China.展开更多
^(231)Pa and ^(230)Th are two crucial isotopes in the ongoing GEOTRACES Project.However,the controversy on ^(231)Pa/^(230)Th proxy pertaining to archiving ocean circulation or recording paleoproductivity,is still unre...^(231)Pa and ^(230)Th are two crucial isotopes in the ongoing GEOTRACES Project.However,the controversy on ^(231)Pa/^(230)Th proxy pertaining to archiving ocean circulation or recording paleoproductivity,is still unresolved,partly owing to the unclear understanding of fractionation between ^(231)Pa and ^(230)Th during adsorption.In this study,controlled experiments were conducted to examine the adsorption of ^(234)Th and ^(233)Pa onto biogenic particles(SiO_(2) and CaCO_(3)),authigenic minerals(MnO_(2) and Fe_(2)O_(3)),and lithogenic minerals(kaolinite,attapulgite,montmorillonite,and aluminum oxyhydroxides),and the role of organic compounds in regulating the adsorption of ^(234)Th and ^(233)Pa in natural seawater was evaluated.The distribution coefficients(K d,presented as logK_(d))varied from 3.56 to 6.05 and from 3.27 to 5.82 for ^(234)Th and ^(233)Pa,respectively.Fe_(2)O_(3) is the strongest sorbent for both ^(234)Th and ^(233)Pa.Most of the particles showed comparable logK_(d) values for either ^(234)Th(~4.8)or ^(233)Pa(~3.9)in the presence of dextran,indicating that the adsorption of Th and Pa is likely controlled by organic coating on particle surfaces.The fractionation factors(F Th/Pa)of SiO_(2)(3±1)and CaCO_(3)(33±1)suggest in situ observed preferential scavenging of ^(230)Th to ^(231)Pa in the surface water of low-to mid-latitude regions and the nearly equal removal in the Antarctic Ocean where biogenic silica dominates the particle regime.The F Th/Pa values of the lithogenic and biogenic particles indicate that ^(230)Th is scavenged prior to ^(231)Pa in the particle-scarce ocean interior.The equal scavenging of ^(230)Th and ^(231)Pa at the ocean margins and the ridge crests is dominated by high particle fl uxes instead of particle composition control.These results imply that ^(230)Th/^(231)Pa can be used as different proxies in different oceanic settings.展开更多
While prokaryotes play key roles in nutrient cycling and energy flow during Phaeocystis globosa blooms,the information on the spatial and diel temporal distribution of the prokaryotic community during Phaeocystis bloo...While prokaryotes play key roles in nutrient cycling and energy flow during Phaeocystis globosa blooms,the information on the spatial and diel temporal distribution of the prokaryotic community during Phaeocystis blooms remains scarce.In January 2019,we used high-throughput sequencing of the 16S rRNA gene to explore the spatial and diel variations of particle-attached(PA)and free-living(FL)prokaryotic communities during the blooming phase of P.globosa in Beibu Gulf,Guangxi,China.The results suggested a significant spatial variation pattern in the horizontal distribution of prokaryotic communities,while there was no significant difference in the vertical direction.Both spatial distance and environmental variables shaped the horizontal distribution of the prokaryotic community structure,while environmental variables,particularly the abundance of P.globosa colony and Chl a,showed more significant influence and were closely related to the structure and variation of the prokaryotic community.Strong vertical mixing of the water column disrupted the vertical structure heterogeneity of the prokaryotic community in winter.There were significant differences in the diel samples of PA prokaryotic communities,but not in the FL prokaryotic communities.Nitrate,ammonium and the abundance of P.globosa colony were the key environmental variables impacting the diel variations of prokaryotic communities over the sampling period.The present study provided valuable information to depict the spatial-temporal variations of the microbial community and its association with environmental parameters during P.globosa bloom in the tropical gulf.展开更多
The coastline,as the boundary between land and sea,is shaped by both natural factors and human activities.Based on concrete practice from coastline survey in Shandong Province,this study discusses the applicability of...The coastline,as the boundary between land and sea,is shaped by both natural factors and human activities.Based on concrete practice from coastline survey in Shandong Province,this study discusses the applicability of the local standard Specification for Coastline Survey(DB 37/T 3588-2019).The coastline classification system takes into account the coastline characteristics and marine management requirements in Shandong Province.To be specific,the coastline with natural beach morphology and ecological function is involved,and its delimitation method is innovated.The coastline delimitation of sandy beach,aquaculture pond and salt pan follows the trace line of the mean high water springs(MHWS),but the coastline location of sandy beach can also be at the base of cliffs or at the foot of seawalls and roads considering the dynamic changes of the beach in different seasons and the integrity of the beach topography.The delineation of estuarial coastline is to achieve the complete coastline,and should not be used for the statistics of natural coastline retention rate.At present,the review of survey results has been completed.With the promulgation of survey results next,the formulation of relevant mechanisms and policies should promptly be put on the agenda,including regular investigation and data updating,natural coastline assessment,natural coastline requisition-compensation,and coastline protection planning.展开更多
In May and October 2017,12 stations were set up in the Central Bohai Sea for fishery resources investigation.The results show that there are many dominant species in this area,and the inshore fishery resources are hig...In May and October 2017,12 stations were set up in the Central Bohai Sea for fishery resources investigation.The results show that there are many dominant species in this area,and the inshore fishery resources are higher than those in the open sea because of the abundant nutrients from land,the high density of zooplankton and the food of swimming animals.In order to effectively protect the fishery resources in the Central Bohai Sea,this paper puts forward some suggestions,such as strengthening the protection propaganda,scientific and reasonable fishing,and strengthening the management of marine environment.展开更多
基金This work was partially supported by the National Key Research and Development Program of China under Grant No.2018AAA0100400the Natural Science Foundation of Shandong Province under Grants Nos.ZR2020MF131 and ZR2021ZD19the Science and Technology Program of Qingdao under Grant No.21-1-4-ny-19-nsh.
文摘UAV marine monitoring plays an essential role in marine environmental protection because of its flexibility and convenience,low cost and convenient maintenance.In marine environmental monitoring,the similarity between objects such as oil spill and sea surface,Spartina alterniflora and algae is high,and the effect of the general segmentation algorithm is poor,which brings new challenges to the segmentation of UAV marine images.Panoramic segmentation can do object detection and semantic segmentation at the same time,which can well solve the polymorphism problem of objects in UAV ocean images.Currently,there are few studies on UAV marine image recognition with panoptic segmentation.In addition,there are no publicly available panoptic segmentation datasets for UAV images.In this work,we collect and annotate UAV images to form a panoptic segmentation UAV dataset named UAV-OUC-SEG and propose a panoptic segmentation method named PanopticUAV.First,to deal with the large intraclass variability in scale,deformable convolution and CBAM attention mechanism are employed in the backbone to obtain more accurate features.Second,due to the complexity and diversity of marine images,boundary masks by the Laplacian operator equation from the ground truth are merged into feature maps to improve boundary segmentation precision.Experiments demonstrate the advantages of PanopticUAV beyond the most other advanced approaches on the UAV-OUC-SEG dataset.
基金Supported by the National Natural Science Foundation of China(No.41776012)the Key R&D Project of Zhejiang Province(No.2020C03012)+4 种基金the Shandong Provincial Natural Science Foundation(No.ZR2020MD059)the Key R&D Project of Guangdong Province(No.2020B1111030002)the Major Science and Technology Project of Sanya YZBSTC(No.SKJC-KJ-2019KY03)the National Key R&D Program of China(No.2019YFD0901305)the Marine Science and Technology Project of North China Sea Bureau in 2020:Tempo-Spatial Distribution and Its Mechanisms of the Bottom Oxygen-Poor Zones in the Bohai Sea(No.202001)。
文摘Deoxygenation has frequently appeared in coastal ecosystems over the past century due to the joint infl uence of increasing anthropogenically induced nutrient inputs and global warming.The semi-enclosed Bohai Sea is a typical system that is prone to deoxygenation,with regular hypoxia events consistently recorded in recent decades.Based on in-situ observation data collected in large-scale voyage surveys in the Bohai Sea during 2008-2017,the seasonal variability in dissolved oxygen(DO)and its controlling mechanisms were studied.The results indicated that in spring and autumn,the DO distributions exhibited similar spatial patterns in the surface and bottom layers,while in summer,its spatial distribution was characterized by large-scale oxygen-poor zones distributed off the Qinhuangdao Coast and the central southern Bohai Sea in the bottom layer.The controlling mechanisms of the DO distribution varied from season to season.Spring and autumn DO distributions were dominated by the seawater temperature.Under the combined eff ects of stratifi cation and decomposition,the summer bottom DO exhibited dual-core distribution.On the one hand,stratifi cation could greatly impede vertical mixing,resulting in reduced bottom DO replenishment.On the other hand,the increased bottom organic matter intensifi ed the decomposition processes,inducing massive DO consumption and elevated dissolved inorganic nitrogen concentrations.In addition,the stronger stratifi cation might be the reason for the more severe deoxygenation in the southern oxygen-poor zones in summer.Our study provides guidance for an in-depth understanding of the DO seasonality in the Bohai Sea and the mechanisms that modulate it and for the improvement of hypoxia forecasts in ocean models.
基金financially supported by the National Science and Technology Major Project (No. 2011ZX050 25-002-03)the Project of China National Offshore Oil Corporation (CNOOC) Limited (No. CCL2013ZJFNO729)the National Natural Science Foundation of China (No. 41530963)
文摘Based on the concentrations of the trace elements,rare earth elements(REE),and Sr isotopic compositions in reef carbonates from the well‘Xike-1’reef core of the Xisha Islands,the constraints on sediment provenance and paleoenvironment were defined.Variations of the terrigenous input into the paleoseawater were traced in detail and the paleoenvironment and sediment provenance were further investigated.The results show that the HREE/LREE values in the reef carbonates are negatively associated with their Th and Al concentrations;however,their Al and Th concentrations show positive correlation.The lowest 87 Sr/86 Sr values in the reef carbonates generally coincide with the lowest values of Al,Th concentrations and the highest values of HREE/LREE.These data indicate that the HREE/LREE,Al concentrations,and Th concentrations of the reef carbonates are useful indexes for evaluating the influence of the terrigenous inputs on the seawater composition in the study area.From top to bottom,the changing process of the HREE/LREE values and Al,Th concentrations can be divided into 6 intervals;they are H1(0–89.30 m,about 0–0.11 Myr),L1(89.30–198.30 m,about 0.11–2.2 Myr),H2(198.30–374.95 m,about 2.2–5.3 Myr),D(374.95–758.40 m,about 5.3–13.6 Myr),L2(758.40–976.86 m,about 13.6–15.5 Myr),and H3(976.86–1200.00 m,about 15.5–21.5 Myr).Moreover,the changing trend of the HREE/LREE values coincides with that of the seawater δ^13C values recorded by benthonic foraminiferal skeletons from the drill core of ODP site 1148 in the South China Sea(SCS),but not with that of the seawaterδ18O values.The high uplifting rates of the Qinghai-Tibet Plateau coincide with the high Th and Al concentrations and the low HREE/LREE values in the reef carbonates.These data indicate that the main factors controlling the changes of terrigenous flux in the SCS are the tectonic activities associated with Qinghai-Tibet Plateau uplifting and the variations of uplifting rates rather than paleoclimatic changes.
基金The study has received support from the National Natural Science Foundation of China(No.41906182)the National Program on Global Change and Air-Sea Interactions(No.GASI-01-WIND-STwin)the Program of Shandong Key Laboratory of Marine Ecological Environment and Disaster Prevention and Mitigation(Nos.202102,202209 and 201901).
文摘Colored dissolved organic matter(CDOM)is a crucial constituent that affects the optical absorption properties of seawater.Owing to the relatively limited measured data on the spatial distribution characteristics of CDOM in the tropical eastern Indian Ocean,this study analyzes the optical absorption characteristics of CDOM in the southeast Indian Ocean using the data collected during four seasons from 2013 to 2017.This work also systematically describes the seasonal horizontal and vertical distribution characteristics of CDOM in this area and conducts a preliminary analysis of the relevant factors affecting CDOM absorption characteristics in this region.Results indicate that the CDOM ag(440)during summer was remarkably lower than that in the coastal waters of Europe and coastal waters of China but slightly higher than that in the western and southeast Pacific.The spatial distribution of surface CDOM shows remarkable seasonal differences,and the spatial distribution characteristics of CDOM in the 5°S,92°E region differ between spring/summer and autumn/winter.The values of ag(400)and ag(440)are weak/strong at a surface/subsurface level of 100 m,with differences found between summer and winter.The correlation of CDOM with temperature,salinity,and chlorophyll-a concentration is relatively low,indicating that CDOM is an independent driving mechanism influenced by phytoplankton degradation,photobleaching,and water mixing.
基金The National Natural Science Foundation of China under contract Nos U22A20580,42130410,U2106203 and 41977173the Fundamental Research Funds for the Central Universities,China under contract No.202341002.
文摘As an important land-ocean interaction process,submarine groundwater discharge(SGD)is composed of multiple dynamical processes at different scales and plays an important role in the study of coastal ocean geochemical budgets.However,most of the existing studies focus on the quantification of the total groundwater discharge,few studies are about the differentiation and quantification of groundwater discharge processes at different scales(i.e.,short-scale SGD and long-scale SGD).As a world-class river,the Huanghe River is highly turbid and heavily regulated by humans.These natural and anthropogenic factors have a significant impact on groundwater discharge processes in the Huanghe River Estuary(HRE).In this study,the distribution patterns of the natural geochemical tracer radium isotopes(^(224)Ra and^(223)Ra)and other hydrological parameters in the HRE were investigated during four cruises.By solving the mass balance of^(224)Ra and^(223)Ra in the HRE,the long-scale SGD flux was quantified as 0.01−0.19 m/d,and the short-scale SGD flux was 0.03−0.04 m/d.The rate of short-scale SGD remained essentially constant among seasons,while the rate of long-scale SGD varied considerably at different periods and showed a synchronous trend with the variation of river discharge.The results of this study are significant for understanding the SGD dynamics in the HRE and the contribution of SGD to the ocean geochemical budgets.
基金financially supported by the National Natural Science Foundation of China(Nos.U22A20580,42130410,and U1906210)the Fundamental Research Funds for the Central Universities(No.201962003).
文摘Natural radionuclides are powerful tools for understanding the sources and fate of suspended particulate matter(SPM).Particulate matter with different particle sizes behaves differently with respect to adsorption and desorption.We analyzed the activi-ties and distribution characteristics of multiple natural radionuclides(238U,226Ra,40K,228Ra,7Be and 210Pbex)on size-fractionated SPM at the Lijin Hydrographic Station(Huanghe or Yellow River)every month over a one-year period.Results showed that medium silt(16–32µm)was the main component.As expected,the activity of each radionuclide decreased with an increase of particle size.We examined the sources of SPM with different particle sizes using activity ratios of 226Ra/238U,228Ra/226Ra,40K/238U and 7Be/210Pbex,and concluded that SPM with different particle sizes originated from different sources.Our results indicate that fine SPM(<32µm)was mainly from the erosion of soil along the lower reaches of the Yellow River,while coarse SPM(>32µm)was mainly derived from resuspension of riverbed sediment.During high runoff periods,the concentration of SPM increased significantly,and the pro-portion of fine particles originating upstream increased.Naturally occurring radioactive isotopes,especially on size-fractionated par-ticles,are therefore seen as useful tracers to understand the sources and behaviors of riverine particles transported from land to sea.
基金supported by the National Natural Science Foundation of China(Nos.41876077,41376085).
文摘As a river with more than 3000 reservoirs in its watershed,the Yellow River has been affected by dams not only on the sediment load,but also on the water quality.Water-sediment regulation scheme(WSRS),which has been carried out annually in the Yellow River since 2002,is a typical human activity affecting river water quality.Chromophoric dissolved organic matter(CDOM)in river is susceptible to changes in ecological and environmental conditions as well as human activities.Here,we report variations in dissolved organic carbon concentrations,compositions and sources of CDOM in time series samples in the lower Yellow River during WSRS.In addition,a parallel factor fluorescence analysis(PARAFAC)method is applied to identify different fluorescent components in water samples during WRSR,showing four major components including tryptophan-like component(C1),microbial humic-like component(C2),terrestrial humic-like component(C3)and tyrosine-like component(C4).In general,C1 increased after water regulation,while C2 and C3 increased after sediment regulation,indicating that the water and sediment released by the dam have different effects on CDOM compositions.Under the impacts of the dam,source of CDOM in the lower Yellow River is mainly autochthonous related to microbial activities,and is regulated by the terrestrial input during WSRS period.Sediment resuspension inhibits microbial activities and reduces the production of autochthonous CDOM.Overall,human activities especially WSRS,as exemplified here,significantly alter the quality and quantity of CDOM in the lower Yellow River,affecting CDOM dynamics and biogeochemical processes in the estuarine environment.
基金Supported by the Knowledge Innovation Project of Chinese Academy of Sciences (No.KZCX 2-207)Zhejiang Bureau of Science and Technology (No.2007C23075)
文摘Based on research results on the impacts of solar light,seawater temperature,and nutrient available to phytoplankton growth and changes in phytoplankton physiology and assemblage,we discussed the order of influence of these factors.By clarifying the mechanisms and processes of the impacts by these factors,we have determined the rising order of the importance as solar light,seawater temperature,and nutrient silicon (Si).Therefore,for human interests in sustaining economic development,the first thing to be considered is the input of nutrient Si into the ocean,followed by seawater temperature change.
文摘In recent years,oil spill accidents occur frequently in the marine area of China.Finding out the spilled oil source is a key step in the relevant investigation.In this paper,a step-by-step fingerprinting identification method was used in a spilled oil accident in the Bohai Sea in 2002.Advanced chemical fingerprinting and data interpretation techniques were used to characterize the chemical composition and determine the possible sources of two spilled oil samples.The original gas chromatography -flame ionization detec-tion (GC-FID) chromatogram of saturated hydrocarbons was compared.The gas chromatography-mass spectrometry (GC/MS) chromatograms of aromatic hydrocarbons terpane and sterane,n-alkane and poly-aromatic hydrocarbons (PAHs) were analyzed.The correlation analysis on diagnostic ratios was performed with Student’s t-test.It is found that the oil fingerprinting of the spilled oil (designated as sz1) from the polluted sand beach was identical with the suspected oil (designated as ky1) from a nearby crude oil refinery factory.They both showed the fingerprinting character of mixed oil.The oil fingerprinting of the spilled oil (designated as ms1) collected from the port was significantly different from oil ky1 and oil sz1 and was with a lubricating oil fingerprint character.The identification result not only gave support for the spilled oil investigation,but also served as an example for studying spilled oil accidents.
基金Supported by the National Key Technology Research and Development Program (863 Program, No. 2006BAD09A06)the Special Fund of Chinese Central Government for Basic Scientific Research Operations in Commonweal Research Institutes (No. 02-2007B03)
文摘Immunostimulants may improve disease resistance of aquaculture animals by promoting the nonspecific immunity response of the organisms. Five types of saccharides, including chitosan, yeast polysaccharide, burdock oligosaccharide, seaweed polysaccharide and lentinus edodes polysaccharide, were screened for potential use as immunostimulants by using spectrophotometry. The saccharides were injected into Apostichopus japonicus, a sea cucumber, and the lysozyme and superoxide dismutase (SOD) activities of the coelomic fluid and epidermal slime were monitored in six consecutive days. The results show that the lysozyme activity of the animal’s coelomic fluid was significantly stimulated on day 2, day 4 and day 6 after the injection of the saccharides (P<0.05). The effects of chitosan and yeast polysaccharide were the most notable. The lysozyme activity of the epidermal slime was significantly increased by chitosana, yeast polysaccharide, seaweed polysaccharide, and burdock oligosaccharide on day 1 and day 2 after the injection (P<0.05). The SOD activity of the coelomic fluid was significantly promoted by the saccharides on day 2 and day 4 post-injection (P<0.05), while the SOD activity of the epidermal slime increased on day 2. These findings indicate that chitosan and yeast polysaccharide are the most effective immunostimulants and potential healthy anti-disease feedstuff for A. japonicus.
基金The Public Science and Technology Research Funds Projects of Ocean under contract No.201005015
文摘The classification and identification for Protoperidinium species are the most difficult work during its taxonomic study. In this research, taxonomic status of Protoperidinium was clarified by tracing its taxonomic history, 23 species belong to genus Protoperidinium on the coasts of China were preliminarily identified, and morphological description and plate patterns were given for each species. The key differences of similar species were also discussed in this study, we believe that P. oceanicum and P. murry, P. tumidum and P. fatulipes, P. globules and P.majus are separate species; P. diabolum should be treated as the valid name instead of the reported names Peridinium globosum or Peridinium longipes; the taxonomic relationship between P. punctulatum and P.subinerme requires further study.
基金Supported by Key Laboratory of Marine Spill Oil Identification and Damage Assessment Technology, SOAthe Director’s Found of the Beihai Monitoring Center, SOA
文摘Statistical analysis on data collected in the Jiaozhou Bay (Shandong, China) from May 1991 to February 1994 and those collected in Hawaii from March 1958 to December 2007 shows dynamic and cyclic changes in atmospheric carbon in the Northern Pacific Ocean (NPO), as well as the variation in space-time distribution of phytoplankton primary production and atmospheric carbon in the study regions. The study indicates that the human beings have imposed an important impact on the changing trends of the atmospheric carbon. Primary production in the Jiaozhou Bay presents a good example in this regard. In this paper, dynamic models of the atmospheric carbon in the NPO, the cyclic variations in the atmospheric carbon, and primary production in the Jiaozhou Bay are studied with simulation curves presented. A set of equations were established that able to calculate the rate and acceleration of increasing carbon discharged anthropologically into the atmosphere and the conversion rate of phytoplankton to atmospheric carbon. Our calculation shows that the amount of atmospheric carbon absorbed by one unit of primary production in the Jiaozhou Bay is (3.21–9.74)×10-9/(mgC·m-2d-1), and the amount of primary production consumed by a unit of atmospheric carbon is 102.66–311.52 (mgC·m-2d-1/10-6). Therefore, we consider that the variation of atmospheric carbon is a dynamic process controlled by the increase of carbon compound and its cyclic variation, and those from anthropologic discharge, and phytoplankton growth.
基金Funded by the Director’s Foundation of the Beihai Monitoring Center and the State Oceanic Administration and Chinese Academy of Sciences (KZCX 2-207).
文摘Desertification has been notably expanding in China in the recent decade, especially in North China where dust/sand storm (DSS) frequently assaulted local communities. Analyses in marine ecology found that the earth ecosystem could be able to complement nutrient silicon for keeping sustain- able development of marine ecosystem, and decreasing CO2 concentration in the atmosphere; as a result, the area of desertification would be enlarged. Modern human being activities have resulted in constant changes in the amount of silicon transport from land into sea, leading to oversupply of nitrogen and phosphorus but silicon in seawater. The proportion of nitrogen, phosphorus and silicon was seriously im- balanced and the limitation of silicon for phytoplankton growth has become more serious. The silicon de- ficiency has damaged the marine ecosystem in coastal regions and slowed down the carbon sedimentation in the atmosphere of the world. The authors believe that the continual discharge of CO2 into the atmos- phere is the cause for the global warming including marine water temperature rise. Consequently, the earth ecosystem would have to trigger its complementary action to resume to the silicon balance by algae bloom in seawater for reducing air and water temperatures. In order to complement nutrient silicon into the sea, the ecosystem would transport silicon via the atmosphere; therefore, the desertification in the in- ner land is a natural reaction. As marine phytoplankton booming can reduce the CO2 concentration in the atmosphere and further ease the green-house effect, during this process, a large amount of silicon are de- manded by the ecosystem, which human being are unable to stop desertification from happening but slow down the progress and ease the risk. Therefore, as an important role in earth ecosystem, people should reduce the CO2 discharge into the atmosphere first; then, the normal function of river transporting silicon must be restored. In this way, the CO2 in the atmosphere can be kept in balance, the global warming slowed down, marine ecosystem development sustained, the drought in inner land eased, and the desert gradually under-controlled.
基金Supported by the Public Science and Technology Research Funds Projects of Ocean(No.201105003-2)the Chinese Polar Environment Comprehensive Investigation&Assessment Programs(No.CHINARE2016-01-02)。
文摘Changes in the marine productivity and sedimentary environment since the last deglaciation in the Ross Sea are presented in this paper.Opal has replaced calcium carbonate as the major biogenic component and has a significantly positive correlation with total organic carbon(TOC),which indicates that siliceous phytoplankton controlled the absorption and release of carbon by the biological pump and was the main producer of marine organic matter.Using the AMS 14C age framework,foraminiferal fossils and redox sensitive elements(RSEs),we found that both the sedimentary environment and marine productivity changed clearly in^11 cal ka BP,which is more likely related with the melting and retreat of the Ross Ice Shelf.In addition,the increase of marine productivity promoted the sinking of more organic-matter to the seabed.A large proportion of oxygen in the bottom water body was consumed and more carbon dioxide was produced during the decomposition of organic matter,making the bottom water body more soluble to calcium carbonate.
基金Supported by the Science&Technology Basic Resources Investigation Program of China(No.2018FY100205)the National Natural Science Foundation of China(No.41776153)+4 种基金the National Key R&D Program of China(No.2018YFD0901500)the Key Deployment Project of Centre for Ocean Mega-Research of ScienceChinese Academy of Science(No.COMS2019Q05)the Key R&D Program of Shandong Province(No.2019GSF107012)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDA23050302)。
文摘The large-scale green tide caused by Ulva has occurred successively in the Yellow Sea since 2007,and new events of green tide also continued to appear in nearby sea areas,indicating an undergoing rapid development of occurrence patterns for harmful macroalgal blooms(HMBs)along coastal China.In August 2021,a green tide occurred for the first time in Bayuquan sea area of Yingkou city,Liaoning Province in the Bohai Sea.In this study,morphological and molecular approaches were used to identify the causative species as U.meridionalis,an alien subtropical alga previously found to dominate green tides in the South China Sea.According to the hydrological data of Bayuquan in summer 2021,combined with morphological and developmental observations for this alga,we hypothesized that the disturbance caused by the typhoon In-Fa might have detached the local U.meridionalis from substrates,especially for those thalli with poorly developed holdfasts,and the ensuing wave-free period with unusually high temperature,which fell in the reported optimum growth temperature for U.meridionalis,might have provided the favorable conditions for the final bloom of the floating seaweeds.This is the first report on the bloom of subtropical U.meridionalis in the north temperate sea zone,indicating that the ecological risk of causing green tides in the future by this rapidly spreading species deserves high attention.
基金supported by the National Key Research and Development Program of China(No.2018YFC1407601).
文摘Ecological protection and high-quality development of the Yellow River basin are becoming part of the national strategy in recent years.The Yellow River Estuary has been seriously affected by human activities.Especially,it has been severely polluted by the nitrogen and phosphorus from land sources,which have caused serious eutrophication and harmful algal blooms.Nutrient criteria,however,was not developed for the Yellow River Estuary,which hindered nutrient management measures and eutrophication risk assessment in this key ecological function zone of China.Based on field data during 2004-2019,we adopted the frequency distribution method,correlation analysis,Linear Regression Model(LRM),Classification and Regression Tree(CART)and Nonparametric Changepoint Analysis(nCPA)methods to establish the nutrient criteria for the adjacent waters of Yellow River Estuary.The water quality criteria of dissolved inorganic nitrogen(DIN)and soluble reactive phosphorus(SRP)are recommended as 244.0μg L^(−1) and 22.4μg L^(−1),respectively.It is hoped that the results will provide scientific basis for the formulation of nutrient standards in this important estuary of China.
基金Supported by the National Natural Science Foundation of China(Nos.42076030,41476061)andNational Key Basic Research Special Foundation Program of China(No.2015CB452902)。
文摘^(231)Pa and ^(230)Th are two crucial isotopes in the ongoing GEOTRACES Project.However,the controversy on ^(231)Pa/^(230)Th proxy pertaining to archiving ocean circulation or recording paleoproductivity,is still unresolved,partly owing to the unclear understanding of fractionation between ^(231)Pa and ^(230)Th during adsorption.In this study,controlled experiments were conducted to examine the adsorption of ^(234)Th and ^(233)Pa onto biogenic particles(SiO_(2) and CaCO_(3)),authigenic minerals(MnO_(2) and Fe_(2)O_(3)),and lithogenic minerals(kaolinite,attapulgite,montmorillonite,and aluminum oxyhydroxides),and the role of organic compounds in regulating the adsorption of ^(234)Th and ^(233)Pa in natural seawater was evaluated.The distribution coefficients(K d,presented as logK_(d))varied from 3.56 to 6.05 and from 3.27 to 5.82 for ^(234)Th and ^(233)Pa,respectively.Fe_(2)O_(3) is the strongest sorbent for both ^(234)Th and ^(233)Pa.Most of the particles showed comparable logK_(d) values for either ^(234)Th(~4.8)or ^(233)Pa(~3.9)in the presence of dextran,indicating that the adsorption of Th and Pa is likely controlled by organic coating on particle surfaces.The fractionation factors(F Th/Pa)of SiO_(2)(3±1)and CaCO_(3)(33±1)suggest in situ observed preferential scavenging of ^(230)Th to ^(231)Pa in the surface water of low-to mid-latitude regions and the nearly equal removal in the Antarctic Ocean where biogenic silica dominates the particle regime.The F Th/Pa values of the lithogenic and biogenic particles indicate that ^(230)Th is scavenged prior to ^(231)Pa in the particle-scarce ocean interior.The equal scavenging of ^(230)Th and ^(231)Pa at the ocean margins and the ridge crests is dominated by high particle fl uxes instead of particle composition control.These results imply that ^(230)Th/^(231)Pa can be used as different proxies in different oceanic settings.
基金The National Key Research and Development Program of the Ministry of Science and Technology,China,under contract No.2017YFC1404300the Scientific and Technological Innovation Project of the Pilot National Laboratory for Marine Science and Technology(Qingdao)under contract No.2016ASKJ02the Aoshan Talents Program of the Pilot National Laboratory for Marine Science and Technology(Qingdao)under contract No.2015ASTP.
文摘While prokaryotes play key roles in nutrient cycling and energy flow during Phaeocystis globosa blooms,the information on the spatial and diel temporal distribution of the prokaryotic community during Phaeocystis blooms remains scarce.In January 2019,we used high-throughput sequencing of the 16S rRNA gene to explore the spatial and diel variations of particle-attached(PA)and free-living(FL)prokaryotic communities during the blooming phase of P.globosa in Beibu Gulf,Guangxi,China.The results suggested a significant spatial variation pattern in the horizontal distribution of prokaryotic communities,while there was no significant difference in the vertical direction.Both spatial distance and environmental variables shaped the horizontal distribution of the prokaryotic community structure,while environmental variables,particularly the abundance of P.globosa colony and Chl a,showed more significant influence and were closely related to the structure and variation of the prokaryotic community.Strong vertical mixing of the water column disrupted the vertical structure heterogeneity of the prokaryotic community in winter.There were significant differences in the diel samples of PA prokaryotic communities,but not in the FL prokaryotic communities.Nitrate,ammonium and the abundance of P.globosa colony were the key environmental variables impacting the diel variations of prokaryotic communities over the sampling period.The present study provided valuable information to depict the spatial-temporal variations of the microbial community and its association with environmental parameters during P.globosa bloom in the tropical gulf.
基金Supported by Project of Continental Coastline Survey of Shandong Province(No.SDGP3700000201902004174)Marine Science and Technology Project of North China Sea Bureau of Ministry of Natural Resources(No.202004).
文摘The coastline,as the boundary between land and sea,is shaped by both natural factors and human activities.Based on concrete practice from coastline survey in Shandong Province,this study discusses the applicability of the local standard Specification for Coastline Survey(DB 37/T 3588-2019).The coastline classification system takes into account the coastline characteristics and marine management requirements in Shandong Province.To be specific,the coastline with natural beach morphology and ecological function is involved,and its delimitation method is innovated.The coastline delimitation of sandy beach,aquaculture pond and salt pan follows the trace line of the mean high water springs(MHWS),but the coastline location of sandy beach can also be at the base of cliffs or at the foot of seawalls and roads considering the dynamic changes of the beach in different seasons and the integrity of the beach topography.The delineation of estuarial coastline is to achieve the complete coastline,and should not be used for the statistics of natural coastline retention rate.At present,the review of survey results has been completed.With the promulgation of survey results next,the formulation of relevant mechanisms and policies should promptly be put on the agenda,including regular investigation and data updating,natural coastline assessment,natural coastline requisition-compensation,and coastline protection planning.
文摘In May and October 2017,12 stations were set up in the Central Bohai Sea for fishery resources investigation.The results show that there are many dominant species in this area,and the inshore fishery resources are higher than those in the open sea because of the abundant nutrients from land,the high density of zooplankton and the food of swimming animals.In order to effectively protect the fishery resources in the Central Bohai Sea,this paper puts forward some suggestions,such as strengthening the protection propaganda,scientific and reasonable fishing,and strengthening the management of marine environment.
