During the South China Sea acquisition system （ATLAS） monsoon experiment （SCSMEX）, three autonomous temperature line buoys with acoustic Doppler in the South China Sea to measure temperature, salinity current prof...During the South China Sea acquisition system （ATLAS） monsoon experiment （SCSMEX）, three autonomous temperature line buoys with acoustic Doppler in the South China Sea to measure temperature, salinity current profiler （ADCP） were moored and current velocity. Typhoon Faith passed through about 250 km south to one of the mooring buoys located at 12~58.5~N, 114~24.5rE from December 11 to 14, 1998. The data analysis indicates that the typhoon winds induce a great increase in the kinetic energy at near-inertial frequencies with two maxima in the mixed layer and thermocline. The near-inertial oscillations were observed at the upper 270 m in the wake of Typhoon Faith. The oscillations were originally excited in the sea surface layer and propagated downward. The amplitudes of the oscillations decrease with depth except in the thermocline. The near-inertial oscillation signals are also remarkable in temperature and salinity fields.展开更多
A quantitative study on the community structure and biodiversity of free-living marine nematodes and their relationship with environmental factors in the northern South China Sea were carried out based on the samples ...A quantitative study on the community structure and biodiversity of free-living marine nematodes and their relationship with environmental factors in the northern South China Sea were carried out based on the samples collected at five stations in the deep sea （from 313 to 1 600 m） and one station in shallowwaters （87 m） during the cruise in September, 2010. Results showed that the abundance of marine nematodes ranged from 224 to 1 996 ind./（10 cm2）. A total of 69 free-living marine nematode genera, belonging to 26 families and three orders, were identified. The most dominant genera were Sabatieria, Linhystera, Aegialoalaimus and Daptonema according to SIMPER analysis. Results of CLUSTER analysis revealed four types of marine nematode community （or station groups） in the sampling area. In terms of trophic structure, non-selective deposit feeders （1B） and selective deposit feeders （1A） were the dominant trophic types with highest genera numbers and abundances, which implied that organic detritus was the main food source of marine nematodes in the northern South China Sea. The percentage of male nematode was low, ranging from 2.22% to 17.81%, while those of juvenile individuals ranged from 36.99% to 82.09%. For genera level diversity of marine nematodes, Shannon-Wiener diversity indices （H＇） ranged from 3.76 to 4.57 and had highly significant negative correlation with water depth. In general, diversity indices H＇ at the five stations in deep sea （over 200 m） were lower than that at the station in shallow waters （87 m）. BIOENV analysis showed that the most important environmental factor controlling marine nematode communities was water denth.展开更多
Two species of Nassarius Duméril, 1805 from the South China Sea are described and illustrated. The specimens are in the Nassariidae collection of the Marine Biological Museum of Chinese Academy of Sciences, Qingd...Two species of Nassarius Duméril, 1805 from the South China Sea are described and illustrated. The specimens are in the Nassariidae collection of the Marine Biological Museum of Chinese Academy of Sciences, Qingdao.Nassarius concavus sp. nov., from the sandy bottom at a depth of 180 m, resembles Nassarius glabrus Zhang and Zhang, 2014 in general shell morphology, but differs from the latter in having a smaller, more slender adult shell without axial ribs on the upper teleoconch whorls. Nassarius nanshaensis sp. nov., from the Nansha Islands at a depth of 56–147 m, is similar to Nassarius maxiutongi Zhang, Zhang and Li, 2019 in the shell sculpture, but differs in having a more slender shell with a higher spire, and fewer cusps on the rachidian tooth(9–11 vs. 13–17).展开更多
The Bering Sea is an area of high biological productivity, with large populations of sea-birds, demersal and pelagic fishes, so it seemed desirable to assess the bioaccumulation of trace metals in the marine organisms...The Bering Sea is an area of high biological productivity, with large populations of sea-birds, demersal and pelagic fishes, so it seemed desirable to assess the bioaccumulation of trace metals in the marine organisms from this area. However, few data on trace metal concentrations are available for the benthopelagic organisms from the Bering Sea till now. Ten specimens of benthos （including 120 biological samples） were collected in the western Bering Sea in August 2008 during the 3rd Chinese National Arctic Research Expeditions, and the concentration of Cd, Cu, Cr and Zn determined using atomic absorption spectrometry. Zn, Cr and Cd concentrations in muscle tissues of the crab species were much higher than those from fish and cephalopod species, and the highest concentration of Cu was observed in the muscle tissues of Cylichna nucleoli. The results showed a similar hierarchy for Zn, Cr, Cd and Cu concentrations among different tissues as follows： hepatopancreas〉muscle tissue〉gonad. Bioconcentration factors indicated that benthic organisms had high accumulation abilities for Zn and Cu.展开更多
Submarine groundwater discharge(SGD),which can be traced using naturally occurring radium isotopes,has been recognized as a significant nutrient source and land-ocean interaction passage for the coastal waters of the ...Submarine groundwater discharge(SGD),which can be traced using naturally occurring radium isotopes,has been recognized as a significant nutrient source and land-ocean interaction passage for the coastal waters of the Daya Bay,China.However,uncertainties in assessing SGD fluxes must still be discussed in detail.In this study,we attempted to utilize the Monte Carlo method to evaluate the uncertainties of radium-derived SGD flux in the northeast and entirety of the Daya Bay.The results show that the uncertainties of the SGD estimate in the northeast bay are very sensitive to variations in excess radium inventories as well as radium inputs from bottom sediments,while the uncertainties of the SGD estimate for the entire bay are strongly affected by fluctuations in radium inputs from bottom sediments and radium end-members of SGD.This study will help to distinguish the key factors controlling the accuracy of SGD estimates in similar coastal waters.展开更多
Genus Nassarius contains many subgenera, such as Zeuxis, Telasco, Niotha, Varicinassa, Plicarcularia, Nassarius s. str. and Reticunassa. On the basis of morphological characteristics of the shell and radula and sequen...Genus Nassarius contains many subgenera, such as Zeuxis, Telasco, Niotha, Varicinassa, Plicarcularia, Nassarius s. str. and Reticunassa. On the basis of morphological characteristics of the shell and radula and sequences of mitochondrial cytochrome oxidase subunit I (COI) and 16S rRNA genes, Nassarius specimens collected from the South China Sea were identified and phylogenetically analyzed. Although Nassarius sp. and Nassarius (Varicinassa) variciferus were morphologically different in their shells, few variations were found among their radular teeth and sequences of mtCOI and mt16S RNA genes. Therefore, Nassarius sp. should be classified as N. (Varicinassa) variciferus. Nassarius (Zeuxis) sp. has only a subtle difference from Nassarius (Zeuxis) algidus on the shell, but it shows obvious differences in radular teeth and DNA sequence, indicating that they are two distinct species. Sequence divergence of mtCOI and mt16S RNA genes within Nassarius species was much lower than that between species, suggesting that these two genes are suitable for Nassarius species identification. Phylogenetic analysis (neighbor-joining and maximum parsimony) based on mtCOI and mt16S rRNA genes revealed the presence of two groups in genus Nassarius and a closest relationship between subgenera Zeuxis and Telasco. Species of subgenus Plicarcularia did not form a single clade. The molecular phylogeny was not congruent with the previous morphological phylogeny. The subgeneric divisions of genus Nassarius appear to be uncertain and unreliable.展开更多
By using flow cytometry techniques, we investigated the abundance and composition of the heterotrophic prokaryotes, virioplankton and picophytoplankton community in the Pearl River Estuary and Daya Bay in the summer o...By using flow cytometry techniques, we investigated the abundance and composition of the heterotrophic prokaryotes, virioplankton and picophytoplankton community in the Pearl River Estuary and Daya Bay in the summer of 2012. We identified two subgroups of prokaryotes, high nucleic acid（HNA） and low nucleic acid（LNA）, characterized by different nucleic acid contents. HNA abundance was significantly correlated with larger phytoplankton and Synechococcus（Syn） abundance, which suggested the important role of organic substrates released from primary producers on bacterial growth. Although LNA did not show any association with environmental variables, it was a vital component of the microbial community. In contrast to previous studies, the total virioplankton concentration had a poor relationship with nutrient availability. The positive relationship between large-sized phytoplankton abundance and the V-I population confirmed that V-I was a phytoplankton-infecting viral subgroup. Although the V-II group（bacteriophages）was dominant in the virioplankton community, it was not related with prokaryotic abundance, which indicated factors other than hosts controlling V-II abundance or the uncertainty of virus-host coupling. With respect to the picophytoplankton community,our results implied that river input exerted a strong limitation to Syn distribution in the estuary, while picoeukaryotes（Euk） were numerically less abundant and showed a quite different distribution pattern from that of Syn, and hence presented ecological properties distinct from Syn in our two studied areas.展开更多
Two sediment cores were retrieved in the hadal zone of the Yap Trench,and their concentrations of six major elements Mg,Al,Ca,Ti,Mn and Fe and nine trace elements Sr,Ba,Pb,V,Cr,Co,Ni,Cu and Zn were determined in induc...Two sediment cores were retrieved in the hadal zone of the Yap Trench,and their concentrations of six major elements Mg,Al,Ca,Ti,Mn and Fe and nine trace elements Sr,Ba,Pb,V,Cr,Co,Ni,Cu and Zn were determined in inductively coupled plasma atomic emission spectrometry(ICP-AES).According to the vertical distribution profiles of the 15 elements,the correlation of their concentrations,the ratios of Ni/Co,V/Cr,Fe/Al,and Ti/Al,and morphological characteristics of the sediment samples,the implications of the depositional environment and the sediment provenance were analyzed.The results show that the ratio of Ni/Co in all depths of the two sediment cores were below 5,and the ratio of V/Cr were lower than 2,indicating that the depositional environment of the hadal zone in the trench was oxidative and might have inflow of the Antarctic bottom oxygen-rich water.The sediment samples on the eastern side of the trench were siliceous mud mainly composed of diatoms,radiolarian,and sponge needles from surface to deep layer.The vertical profile of the elements,the concentration of TOC and the fossil record indicated that the sediment sample from station Dive113 was well mixed from surface to bottom layer.Based on the correlation of concentrations of the elements,the morphological characteristics of the sediment,and the ratios of Fe/Al and Ti/Al,we inferred that the sediment in the hadal zone of the trench had terrestrial,volcanic,biological,and authigenic sources.Major source of the sediment in the eastern side of the trench were terrestrial;whereas the sediment in the western side of the trench received more volcaniclastic input.展开更多
Temperature （T） and salinity （S） profiles from conductivity-temperature-depth data collected during the Northern South China Sea Open Cruise from August 16 to September 13, 2008 are assimilated using Ensemble Kalm...Temperature （T） and salinity （S） profiles from conductivity-temperature-depth data collected during the Northern South China Sea Open Cruise from August 16 to September 13, 2008 are assimilated using Ensemble Kalman Filter （EnKF）. An adaptive observational error strategy is used to prevent filter from diverging. In the meantime, aiming at the limited improvement in some sites caused by the T and S biases in the model, a T-S constraint scheme is adopted to improve the assimilation performance, where T and S are separately updated at these locations. Validation is performed by comparing assimilated outputs with independent in situ data （satellite remote sensing sea level anomaly （SLA）, the OSCAR velocity product and shipboard ADCP）. The results show that the new EnKF assimilation scheme can significantly reduce the root mean square error （RMSE） of oceanic T and S compared with the control run and traditional EnKF. The system can also improve the simulation of circulations and SLA.展开更多
Phytoplankton abundance was found to be positively correlated with seasonal changes of seawater temperature in Port Shelter and Lamma Channel, Hong Kong in 1998. Rising water temperature from around 20℃ to 25℃ coinc...Phytoplankton abundance was found to be positively correlated with seasonal changes of seawater temperature in Port Shelter and Lamma Channel, Hong Kong in 1998. Rising water temperature from around 20℃ to 25℃ coincided with an increase in phytoplankton abundance at both locations. Heavy rains from June to September reduced salinity from 30 to 20, but the decrease in salinity was not correlated with a decline in phytoplankton abundance. In spring 1998, over 0.6×10^6 cells dm^-3 and 0.1× 10^6 cells dm^-3 of the dinoflagellate, Gymnodinium mikimotoi Miyake et Kominami ex Oda occurred in the coastal waters of Port Shelter and Lamina Channel, respectively. High abundance of the dinoflagellate Ceratium furca （Ehr.） Claparede et Lachmann （〉1×10^6 cells dm^-3） produced long-lasting blooms in the waters of Port Shelter from September to October in 1998. The abundances of both diatoms and dinoflagellates were significantly lower in the waters of Lamina Channel than those in Port Shelter due to the less frequent blooms in 1998. Hydrographic conditions such as stable water masses and water column stratification were the main reasons for the differences in the algal abundance and bloom frequency found between the two locations since neither of the two areas appeared to be nutrient-limited. This type water condition for the formation of algal bloom in Port Shelter has not been reported previously and it is not a general case for many bays along China＇s coast where algal bloom occurs as well.展开更多
This paper reports the distribution of natural radionuclides of 224, 223Ra in the surface water and stratified waters of the Luzon Strait and its adjacent waters during the cruises of September 2015 and May 2016. To u...This paper reports the distribution of natural radionuclides of 224, 223Ra in the surface water and stratified waters of the Luzon Strait and its adjacent waters during the cruises of September 2015 and May 2016. To understand the impact of the Fukushima nuclear accident, the artificial radionuclide 137Cs in the waters was also analyzed. The results showed that the activities of 224, 223Ra and 137Cs were all within the natural radioactive background levels of the marine environment in the South China Sea. 224Ra had a higher activity level in the water of the north South China Sea to the west of the Luzon Strait, and a lower activity level in the oceanic Philippine Sea to the east. The137Cs activity had no obvious spatial trends. Based on the vertical trends of 224Ra, 137Cs, and water temperature and salinity at three stations(LS3, LS5 and LS8), the distinct characteristics of the activity levels and gradients of224Ra and 137Cs among the tropical surface water, subsurface water and mid-deep water were revealed. Typhoon Rainbow event reversed the overall circulation of the Luzon Strait and its adjacent area. A huge amount of western Pacific water characterized by low 224Ra activities flooded into the South China Sea, reducing the activity level of224Ra in the waters. However, there were no significant differences of 137Cs activity between the West Pacific and the north South China Sea, and ocean current changes had no effect on the 137Cs activity levels of the water bodies.展开更多
During the summer of 2011, a severe drought event occurred throughout the Zhujiang （Pearl） River Basin of South China. This decreased runoffinto the river, resulting in increased salinity and reduced suspended subst...During the summer of 2011, a severe drought event occurred throughout the Zhujiang （Pearl） River Basin of South China. This decreased runoffinto the river, resulting in increased salinity and reduced suspended substance. To examine the effects of this extreme drought on the distribution of nutrients and chlorophyll, we compared two surveys from 2006 and 20ll. Results show that dissolved inorganic nitrogen concentration did not change from 2006 to 2011, whereas the proportions of NOR and NH4＋ to DIN in 2011 increased. PO4 3- concentration was lower in 2011 than in 2006, whereas there was no difference in SiO3 2- concentration between these years. Correlation coefficients of salinity with levels of NO3-, NO2-, NH4＋, PO4 3- and SiO3 2- in 2011 were all much higher than those in 2006, suggesting greater conservation of dissolved nutrients during the extreme drought event. Furthermore, calculated amounts of regenerated nitrate and phosphorus and their proportions to observed nutrients in 2011 were much lower than in 2006, indicating that nutrient regeneration decreased during the extreme drought period. Mean concentration of chlorophyll a （Chl-a） was considerably higher in 2011 than in 2006, and a harmful algal bloom of Cochlodinium geminatum was observed in the estuary, owing to water stagnancy and lower turbidity as a consequence of drought. Therefore, the extreme drought event in 2011 changed the composition ratio of nutrients, enhanced nutrient conservative behavior, and reduced nutrient regeneration. This affected some key ecological processes in the estuary.展开更多
Radium （Ra） isotopes are useful for tracing water mass transport and examining estuarine hydrological dynamics. In this study, several hydrological parameters, nutrients, ehlorophyll-a （ehl-a）, suspended particula...Radium （Ra） isotopes are useful for tracing water mass transport and examining estuarine hydrological dynamics. In this study, several hydrological parameters, nutrients, ehlorophyll-a （ehl-a）, suspended particulate matter （SPM） and Ra isotopes （223Ra, 224Ra and 226Ra） of surface waters of the Zhujiang （Pearl） River estuary （ZRE） were measured. This was done for both winter （December） and summer （July） seasons, to quantitatively understand the seasonal characteristics of river plume flow rate and trajectories, as well as the ecological response. The results show that Ra concentrations in summer were higher than in winter, especially Z24Ra （about 2-5 times higher）. The spatial distribution of three Ra isotopes and relative Ra water ages indicated that river water mainly flushed out of ZRE through the western side in winter, where the water transport was about 5 days faster than in the eastern zone. In summer, diluted river water expended to the east side, resulting in fairly similar water ages for both sides of the river mouth. Although nutrients were higher during the summer season, lower chl-a concentrations indicated that reduced primary production might be caused by high SPM （low light penetration）. The results obtained from this study will provide knowledge needed for effectively developing and managing the ZRE.展开更多
Marine ranching is a new model for restoring marine ecological environment and conserving offshore fishery resources.Offshore wind power is a new clean energy industry in China.Based on the analysis of the constructio...Marine ranching is a new model for restoring marine ecological environment and conserving offshore fishery resources.Offshore wind power is a new clean energy industry in China.Based on the analysis of the construction of offshore wind farms in Guangdong Province,this article proposes to actively promote the integrated development of offshore wind power and marine ranching.The suitability and deployment conditions of Sargasso algae reef construction in offshore wind farms,the feasibility of developing an integrated development model featuring artificial algae reefs+offshore wind farms in Guangdong Province,as well as the importance of ecological sea area use and management were discussed.Regarding the necessity of intensive and economical utilization of sea and sea resources,it is believed that the development model of"marine ranching+offshore wind power"will become an important direction for improving the comprehensive utilization of sea areas in the future.展开更多
This paper proposes a new method to classify remote sensing data by using Particle Swarm Optimization (PSO). This method is to generate classification rules through simulating the behaviors of bird flocking. Optimized...This paper proposes a new method to classify remote sensing data by using Particle Swarm Optimization (PSO). This method is to generate classification rules through simulating the behaviors of bird flocking. Optimized intervals of each band are found by p展开更多
基金The National Natural Science Foundation of China under contract Nos 40976013 (for Sun and Hu) and 40830851 (for Wang)the Knowledge Innovation Project for Distinguished Young Scholar of the Chinese Academy of Sciences No.KZCX2EW-QN203 (for Sun)+1 种基金the National Basic Research Program ("973" Program) of China under contract No.2011CB403504 (for Wang)the National Science Foundation of the United States of America under contract No.AGS-1061998 (for Zheng)
文摘During the South China Sea acquisition system （ATLAS） monsoon experiment （SCSMEX）, three autonomous temperature line buoys with acoustic Doppler in the South China Sea to measure temperature, salinity current profiler （ADCP） were moored and current velocity. Typhoon Faith passed through about 250 km south to one of the mooring buoys located at 12~58.5~N, 114~24.5rE from December 11 to 14, 1998. The data analysis indicates that the typhoon winds induce a great increase in the kinetic energy at near-inertial frequencies with two maxima in the mixed layer and thermocline. The near-inertial oscillations were observed at the upper 270 m in the wake of Typhoon Faith. The oscillations were originally excited in the sea surface layer and propagated downward. The amplitudes of the oscillations decrease with depth except in the thermocline. The near-inertial oscillation signals are also remarkable in temperature and salinity fields.
基金The Fundamental Research Funds for Central Universities of the Ministry of Education of China from Ocean University of China under contract Nos 201362018 and 201462008the National Natural Science Foundation of China under contract No.41006081the Scientific Research Award Foundation for Outstanding Middle-aged and Young Scientists of Shandong Province under contract No.BS2013HZ008
文摘A quantitative study on the community structure and biodiversity of free-living marine nematodes and their relationship with environmental factors in the northern South China Sea were carried out based on the samples collected at five stations in the deep sea （from 313 to 1 600 m） and one station in shallowwaters （87 m） during the cruise in September, 2010. Results showed that the abundance of marine nematodes ranged from 224 to 1 996 ind./（10 cm2）. A total of 69 free-living marine nematode genera, belonging to 26 families and three orders, were identified. The most dominant genera were Sabatieria, Linhystera, Aegialoalaimus and Daptonema according to SIMPER analysis. Results of CLUSTER analysis revealed four types of marine nematode community （or station groups） in the sampling area. In terms of trophic structure, non-selective deposit feeders （1B） and selective deposit feeders （1A） were the dominant trophic types with highest genera numbers and abundances, which implied that organic detritus was the main food source of marine nematodes in the northern South China Sea. The percentage of male nematode was low, ranging from 2.22% to 17.81%, while those of juvenile individuals ranged from 36.99% to 82.09%. For genera level diversity of marine nematodes, Shannon-Wiener diversity indices （H＇） ranged from 3.76 to 4.57 and had highly significant negative correlation with water depth. In general, diversity indices H＇ at the five stations in deep sea （over 200 m） were lower than that at the station in shallow waters （87 m）. BIOENV analysis showed that the most important environmental factor controlling marine nematode communities was water denth.
基金The National Natural Science Foundation of China under contract Nos 31750002 and 41606191。
文摘Two species of Nassarius Duméril, 1805 from the South China Sea are described and illustrated. The specimens are in the Nassariidae collection of the Marine Biological Museum of Chinese Academy of Sciences, Qingdao.Nassarius concavus sp. nov., from the sandy bottom at a depth of 180 m, resembles Nassarius glabrus Zhang and Zhang, 2014 in general shell morphology, but differs from the latter in having a smaller, more slender adult shell without axial ribs on the upper teleoconch whorls. Nassarius nanshaensis sp. nov., from the Nansha Islands at a depth of 56–147 m, is similar to Nassarius maxiutongi Zhang, Zhang and Li, 2019 in the shell sculpture, but differs in having a more slender shell with a higher spire, and fewer cusps on the rachidian tooth(9–11 vs. 13–17).
基金The National Natural Science Foundation of China under contract Nos 40776040 and 41076133the Ocean Public Welfare Scientific Research Project,State Oceanic Administration of China(SOAC)under contract No.CHINARE2012-03-04+1 种基金the Marine Science Base Project for Scientific Research Training and Capacity Enhancement-Xiamen Universitysupported by the National Natural Science Foundation of China under contract No.J1210050
文摘The Bering Sea is an area of high biological productivity, with large populations of sea-birds, demersal and pelagic fishes, so it seemed desirable to assess the bioaccumulation of trace metals in the marine organisms from this area. However, few data on trace metal concentrations are available for the benthopelagic organisms from the Bering Sea till now. Ten specimens of benthos （including 120 biological samples） were collected in the western Bering Sea in August 2008 during the 3rd Chinese National Arctic Research Expeditions, and the concentration of Cd, Cu, Cr and Zn determined using atomic absorption spectrometry. Zn, Cr and Cd concentrations in muscle tissues of the crab species were much higher than those from fish and cephalopod species, and the highest concentration of Cu was observed in the muscle tissues of Cylichna nucleoli. The results showed a similar hierarchy for Zn, Cr, Cd and Cu concentrations among different tissues as follows： hepatopancreas〉muscle tissue〉gonad. Bioconcentration factors indicated that benthic organisms had high accumulation abilities for Zn and Cu.
基金The Project of Key Laboratory of Marine Environmental Survey Technology and Application,Ministry of Natural Resources under contract No.MESTA-2021-D006the China Ocean Development Foundation under contract No.CODF-002-ZX-2021+5 种基金the Science and Technology Plan Projects of Guangdong Province under contract No.2021B1212050025the Director’s Foundation of South China Sea Bureau of Ministry of Natural Resources under contract No.230201the Research Fund Program of Guangdong Provincial Key Laboratory of Applied Marine Biology under contract No.LAMB20221007the Natural Science Foundation of Guangdong Province of China under contract No.2017A030310592the Key Program of Bureau Director of State Oceanic Administration under contract No.180104the Open Project of State Key Laboratory of Tropical Oceanography,South China Sea Institute of Oceanology,Chinese Academy of Sciences under contract No.LTO1709.
文摘Submarine groundwater discharge(SGD),which can be traced using naturally occurring radium isotopes,has been recognized as a significant nutrient source and land-ocean interaction passage for the coastal waters of the Daya Bay,China.However,uncertainties in assessing SGD fluxes must still be discussed in detail.In this study,we attempted to utilize the Monte Carlo method to evaluate the uncertainties of radium-derived SGD flux in the northeast and entirety of the Daya Bay.The results show that the uncertainties of the SGD estimate in the northeast bay are very sensitive to variations in excess radium inventories as well as radium inputs from bottom sediments,while the uncertainties of the SGD estimate for the entire bay are strongly affected by fluctuations in radium inputs from bottom sediments and radium end-members of SGD.This study will help to distinguish the key factors controlling the accuracy of SGD estimates in similar coastal waters.
基金Supported by the Youth Science Foundation of the State Oceanic Administration (No. 2009106)the Directorate Foundation of South China Sea Branch, the State Oceanic Administration (No. 0815)
文摘Genus Nassarius contains many subgenera, such as Zeuxis, Telasco, Niotha, Varicinassa, Plicarcularia, Nassarius s. str. and Reticunassa. On the basis of morphological characteristics of the shell and radula and sequences of mitochondrial cytochrome oxidase subunit I (COI) and 16S rRNA genes, Nassarius specimens collected from the South China Sea were identified and phylogenetically analyzed. Although Nassarius sp. and Nassarius (Varicinassa) variciferus were morphologically different in their shells, few variations were found among their radular teeth and sequences of mtCOI and mt16S RNA genes. Therefore, Nassarius sp. should be classified as N. (Varicinassa) variciferus. Nassarius (Zeuxis) sp. has only a subtle difference from Nassarius (Zeuxis) algidus on the shell, but it shows obvious differences in radular teeth and DNA sequence, indicating that they are two distinct species. Sequence divergence of mtCOI and mt16S RNA genes within Nassarius species was much lower than that between species, suggesting that these two genes are suitable for Nassarius species identification. Phylogenetic analysis (neighbor-joining and maximum parsimony) based on mtCOI and mt16S rRNA genes revealed the presence of two groups in genus Nassarius and a closest relationship between subgenera Zeuxis and Telasco. Species of subgenus Plicarcularia did not form a single clade. The molecular phylogeny was not congruent with the previous morphological phylogeny. The subgeneric divisions of genus Nassarius appear to be uncertain and unreliable.
基金supported by the National Basic Research Program (973 Program) of China (Nos. 2015CB452905, 2015CB452903)the Strategic Priority Research Program of the Chinese Academy of Sciences (No. XDA11020205)+1 种基金Fund of Key Laboratory of Global Change and Marine-Atmospheric Chemistry, SOA, (GCMAC1209)Public science and technology research funds projects of ocean (201105015-06)
文摘By using flow cytometry techniques, we investigated the abundance and composition of the heterotrophic prokaryotes, virioplankton and picophytoplankton community in the Pearl River Estuary and Daya Bay in the summer of 2012. We identified two subgroups of prokaryotes, high nucleic acid（HNA） and low nucleic acid（LNA）, characterized by different nucleic acid contents. HNA abundance was significantly correlated with larger phytoplankton and Synechococcus（Syn） abundance, which suggested the important role of organic substrates released from primary producers on bacterial growth. Although LNA did not show any association with environmental variables, it was a vital component of the microbial community. In contrast to previous studies, the total virioplankton concentration had a poor relationship with nutrient availability. The positive relationship between large-sized phytoplankton abundance and the V-I population confirmed that V-I was a phytoplankton-infecting viral subgroup. Although the V-II group（bacteriophages）was dominant in the virioplankton community, it was not related with prokaryotic abundance, which indicated factors other than hosts controlling V-II abundance or the uncertainty of virus-host coupling. With respect to the picophytoplankton community,our results implied that river input exerted a strong limitation to Syn distribution in the estuary, while picoeukaryotes（Euk） were numerically less abundant and showed a quite different distribution pattern from that of Syn, and hence presented ecological properties distinct from Syn in our two studied areas.
基金Supported by the National Basic Research Program of China(973 Program)(No.2015CB755904)the National Natural Science Foundation of China(No.41676067)+1 种基金the Fundamental Funds for Central Universities,China(No.201762030)the Overseas Expertise Introduction Project for Discipline Innovation(111 Project)(No.B13030)。
文摘Two sediment cores were retrieved in the hadal zone of the Yap Trench,and their concentrations of six major elements Mg,Al,Ca,Ti,Mn and Fe and nine trace elements Sr,Ba,Pb,V,Cr,Co,Ni,Cu and Zn were determined in inductively coupled plasma atomic emission spectrometry(ICP-AES).According to the vertical distribution profiles of the 15 elements,the correlation of their concentrations,the ratios of Ni/Co,V/Cr,Fe/Al,and Ti/Al,and morphological characteristics of the sediment samples,the implications of the depositional environment and the sediment provenance were analyzed.The results show that the ratio of Ni/Co in all depths of the two sediment cores were below 5,and the ratio of V/Cr were lower than 2,indicating that the depositional environment of the hadal zone in the trench was oxidative and might have inflow of the Antarctic bottom oxygen-rich water.The sediment samples on the eastern side of the trench were siliceous mud mainly composed of diatoms,radiolarian,and sponge needles from surface to deep layer.The vertical profile of the elements,the concentration of TOC and the fossil record indicated that the sediment sample from station Dive113 was well mixed from surface to bottom layer.Based on the correlation of concentrations of the elements,the morphological characteristics of the sediment,and the ratios of Fe/Al and Ti/Al,we inferred that the sediment in the hadal zone of the trench had terrestrial,volcanic,biological,and authigenic sources.Major source of the sediment in the eastern side of the trench were terrestrial;whereas the sediment in the western side of the trench received more volcaniclastic input.
基金The Strategic Priority Research Program of the Chinese Academy of Sciences under contract No.XDA10010405the Promgram of Guangdong Province Department of Science and Technology No.2012A032100004+1 种基金the National Natural Science Foundation of China under contract Nos 41476012,41521005 and 41406131the Knowledge Innovation Program of the Chinese Academy of Sciences under contract Nos SQ201001 and SQ201205
文摘Temperature （T） and salinity （S） profiles from conductivity-temperature-depth data collected during the Northern South China Sea Open Cruise from August 16 to September 13, 2008 are assimilated using Ensemble Kalman Filter （EnKF）. An adaptive observational error strategy is used to prevent filter from diverging. In the meantime, aiming at the limited improvement in some sites caused by the T and S biases in the model, a T-S constraint scheme is adopted to improve the assimilation performance, where T and S are separately updated at these locations. Validation is performed by comparing assimilated outputs with independent in situ data （satellite remote sensing sea level anomaly （SLA）, the OSCAR velocity product and shipboard ADCP）. The results show that the new EnKF assimilation scheme can significantly reduce the root mean square error （RMSE） of oceanic T and S compared with the control run and traditional EnKF. The system can also improve the simulation of circulations and SLA.
基金Supported by the Project for Coastal Sea Investigation and Assessment in China (No. 908-02-03-09, 908-01-ST06and FJ908-01-01-HS)the Natural Science Foundation of China (No.10705019)
文摘Phytoplankton abundance was found to be positively correlated with seasonal changes of seawater temperature in Port Shelter and Lamma Channel, Hong Kong in 1998. Rising water temperature from around 20℃ to 25℃ coincided with an increase in phytoplankton abundance at both locations. Heavy rains from June to September reduced salinity from 30 to 20, but the decrease in salinity was not correlated with a decline in phytoplankton abundance. In spring 1998, over 0.6×10^6 cells dm^-3 and 0.1× 10^6 cells dm^-3 of the dinoflagellate, Gymnodinium mikimotoi Miyake et Kominami ex Oda occurred in the coastal waters of Port Shelter and Lamina Channel, respectively. High abundance of the dinoflagellate Ceratium furca （Ehr.） Claparede et Lachmann （〉1×10^6 cells dm^-3） produced long-lasting blooms in the waters of Port Shelter from September to October in 1998. The abundances of both diatoms and dinoflagellates were significantly lower in the waters of Lamina Channel than those in Port Shelter due to the less frequent blooms in 1998. Hydrographic conditions such as stable water masses and water column stratification were the main reasons for the differences in the algal abundance and bloom frequency found between the two locations since neither of the two areas appeared to be nutrient-limited. This type water condition for the formation of algal bloom in Port Shelter has not been reported previously and it is not a general case for many bays along China＇s coast where algal bloom occurs as well.
基金The Natural Science Foundation of Guangdong Province of China under contract No.2017A030310592the Open Project of State Key Laboratory of Tropical Oceanography,South China Sea Institute of Oceanology,Chinese Academy of Sciences under contract No.LTO1709the Key Program of Bureau Director of State Oceanic Administration,P.R.China under contract No.180104
文摘This paper reports the distribution of natural radionuclides of 224, 223Ra in the surface water and stratified waters of the Luzon Strait and its adjacent waters during the cruises of September 2015 and May 2016. To understand the impact of the Fukushima nuclear accident, the artificial radionuclide 137Cs in the waters was also analyzed. The results showed that the activities of 224, 223Ra and 137Cs were all within the natural radioactive background levels of the marine environment in the South China Sea. 224Ra had a higher activity level in the water of the north South China Sea to the west of the Luzon Strait, and a lower activity level in the oceanic Philippine Sea to the east. The137Cs activity had no obvious spatial trends. Based on the vertical trends of 224Ra, 137Cs, and water temperature and salinity at three stations(LS3, LS5 and LS8), the distinct characteristics of the activity levels and gradients of224Ra and 137Cs among the tropical surface water, subsurface water and mid-deep water were revealed. Typhoon Rainbow event reversed the overall circulation of the Luzon Strait and its adjacent area. A huge amount of western Pacific water characterized by low 224Ra activities flooded into the South China Sea, reducing the activity level of224Ra in the waters. However, there were no significant differences of 137Cs activity between the West Pacific and the north South China Sea, and ocean current changes had no effect on the 137Cs activity levels of the water bodies.
基金Supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDA11020205)the National Natural Science Foundation of China(Nos.41076069,40776086)+1 种基金the Knowledge Innovation Program of Chinese Academy of Sciences(No.KZCX2-YW-Q07)the National 908 Special Project of China(No.GD908-JC-06)
文摘During the summer of 2011, a severe drought event occurred throughout the Zhujiang （Pearl） River Basin of South China. This decreased runoffinto the river, resulting in increased salinity and reduced suspended substance. To examine the effects of this extreme drought on the distribution of nutrients and chlorophyll, we compared two surveys from 2006 and 20ll. Results show that dissolved inorganic nitrogen concentration did not change from 2006 to 2011, whereas the proportions of NOR and NH4＋ to DIN in 2011 increased. PO4 3- concentration was lower in 2011 than in 2006, whereas there was no difference in SiO3 2- concentration between these years. Correlation coefficients of salinity with levels of NO3-, NO2-, NH4＋, PO4 3- and SiO3 2- in 2011 were all much higher than those in 2006, suggesting greater conservation of dissolved nutrients during the extreme drought event. Furthermore, calculated amounts of regenerated nitrate and phosphorus and their proportions to observed nutrients in 2011 were much lower than in 2006, indicating that nutrient regeneration decreased during the extreme drought period. Mean concentration of chlorophyll a （Chl-a） was considerably higher in 2011 than in 2006, and a harmful algal bloom of Cochlodinium geminatum was observed in the estuary, owing to water stagnancy and lower turbidity as a consequence of drought. Therefore, the extreme drought event in 2011 changed the composition ratio of nutrients, enhanced nutrient conservative behavior, and reduced nutrient regeneration. This affected some key ecological processes in the estuary.
基金Supported by the National Natural Science Foundation of China(Nos.41576075,41106072,41376085)the Natural Science Foundation of Shangdong Province(No.ZR2012DQ002)the Ministry of Land and Resources Program(Nos.GZH201200505,201411072)
文摘Radium （Ra） isotopes are useful for tracing water mass transport and examining estuarine hydrological dynamics. In this study, several hydrological parameters, nutrients, ehlorophyll-a （ehl-a）, suspended particulate matter （SPM） and Ra isotopes （223Ra, 224Ra and 226Ra） of surface waters of the Zhujiang （Pearl） River estuary （ZRE） were measured. This was done for both winter （December） and summer （July） seasons, to quantitatively understand the seasonal characteristics of river plume flow rate and trajectories, as well as the ecological response. The results show that Ra concentrations in summer were higher than in winter, especially Z24Ra （about 2-5 times higher）. The spatial distribution of three Ra isotopes and relative Ra water ages indicated that river water mainly flushed out of ZRE through the western side in winter, where the water transport was about 5 days faster than in the eastern zone. In summer, diluted river water expended to the east side, resulting in fairly similar water ages for both sides of the river mouth. Although nutrients were higher during the summer season, lower chl-a concentrations indicated that reduced primary production might be caused by high SPM （low light penetration）. The results obtained from this study will provide knowledge needed for effectively developing and managing the ZRE.
文摘Marine ranching is a new model for restoring marine ecological environment and conserving offshore fishery resources.Offshore wind power is a new clean energy industry in China.Based on the analysis of the construction of offshore wind farms in Guangdong Province,this article proposes to actively promote the integrated development of offshore wind power and marine ranching.The suitability and deployment conditions of Sargasso algae reef construction in offshore wind farms,the feasibility of developing an integrated development model featuring artificial algae reefs+offshore wind farms in Guangdong Province,as well as the importance of ecological sea area use and management were discussed.Regarding the necessity of intensive and economical utilization of sea and sea resources,it is believed that the development model of"marine ranching+offshore wind power"will become an important direction for improving the comprehensive utilization of sea areas in the future.
基金the National Outstanding Youth Foundation of China (Grant No. 40525002)the National Natural Science Foundation of China (Grant No. 40471105)the Hi-tech Research and Development Program of China (863 Program) (Grant No. 2006AA12Z206).
文摘This paper proposes a new method to classify remote sensing data by using Particle Swarm Optimization (PSO). This method is to generate classification rules through simulating the behaviors of bird flocking. Optimized intervals of each band are found by p
