2018 Vol. 40, No. 10
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2018, 40(10): .
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2018, 40(10): .
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2018, 40(10): 1-13.
doi: 10.3969/j.issn.0253-4193.2018.10.001
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The marine sediment/particles is the key sources and sinks of the biogenic elements in marine environments. On the one hand, the marine sediment/particles is the main sink of the biogenic elements, the biogenic elements from the dissolved state may be changed into particles by complex biochemical processes and the particulate matter can be settled to form sediments, on the other hand, marine sediment/particles can be decomposed by microorganisms-zooplankton-benthos and the biogenic elements released into seawater to be used again by phytoplankton. Therefore, the marine sediment/particles have the very important ecological functions. Phytoplankton is the absorptioner of dissolved biogenic elements in seawaters and the initial formationer of the particle biogenic elements. Zooplankton can also use dissolved biogenic elements or form larger particles by feeding on phytoplankton or other organic particulates, which plays a key role in the particulate biogenic element cycling. The particles can settle to sediments and release the biogenic elements into the water by the processes of feeding-disturbance-breakup of benthic organisms. The functions of different biological communities in ecosystems are different but interrelated in the mineralization processes of releasement and sedimentation of the biogenic elements in particulate. In particular, the ingestion and metabolism of zooplankton and benthos, and the decomposition process of microorganisms play very important role in the biogenic elements. Therefore, the research of marine sediment/particles ecological functions, as a support of the marine environment-resources sustainable use and the marine scientific frontier areas, will get the development by leaps and bounds.
The marine sediment/particles is the key sources and sinks of the biogenic elements in marine environments. On the one hand, the marine sediment/particles is the main sink of the biogenic elements, the biogenic elements from the dissolved state may be changed into particles by complex biochemical processes and the particulate matter can be settled to form sediments, on the other hand, marine sediment/particles can be decomposed by microorganisms-zooplankton-benthos and the biogenic elements released into seawater to be used again by phytoplankton. Therefore, the marine sediment/particles have the very important ecological functions. Phytoplankton is the absorptioner of dissolved biogenic elements in seawaters and the initial formationer of the particle biogenic elements. Zooplankton can also use dissolved biogenic elements or form larger particles by feeding on phytoplankton or other organic particulates, which plays a key role in the particulate biogenic element cycling. The particles can settle to sediments and release the biogenic elements into the water by the processes of feeding-disturbance-breakup of benthic organisms. The functions of different biological communities in ecosystems are different but interrelated in the mineralization processes of releasement and sedimentation of the biogenic elements in particulate. In particular, the ingestion and metabolism of zooplankton and benthos, and the decomposition process of microorganisms play very important role in the biogenic elements. Therefore, the research of marine sediment/particles ecological functions, as a support of the marine environment-resources sustainable use and the marine scientific frontier areas, will get the development by leaps and bounds.
2018, 40(10): 14-21.
doi: 10.3969/j.issn.0253-4193.2018.10.002
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Marine biogenic active gases mainly include dimethylsulfide (DMS), methane (CH4), nitrous oxide (N2O), carbon monoxide (CO), volatile halocarbons (VHCs) and non-methane hydrocarbons (NMHCs). These biogenic active gases are released into the atmosphere through the air-sea exchange and play critical roles not only in global cycling of carbon, nitrogen and sulfur but also in the direct and indirect influences on the climate and environmental changes. Some marine biogenic active gases belong to greenhouse gases (CH4, N2O, VHCs and CO), and others would participate in chemical reactions in the atmosphere and control atmospheric chemical equilibrium and ozone concentration (VHCs and NMHCs). By contrast, DMS is a negative greenhouse effect gas. It will be rapidly oxidized to produce sulfate aerosol in the atmosphere and influence cloudy formation and the Earth's radiative budget. The present research status of marine biogenic active gases is reviewed and the sources and sinks, sea-to-air fluxes of DMS, CH4 and N2O as well as their influencing factors are summarized. Finally, some problems existing in the field and future research directions are presented.
Marine biogenic active gases mainly include dimethylsulfide (DMS), methane (CH4), nitrous oxide (N2O), carbon monoxide (CO), volatile halocarbons (VHCs) and non-methane hydrocarbons (NMHCs). These biogenic active gases are released into the atmosphere through the air-sea exchange and play critical roles not only in global cycling of carbon, nitrogen and sulfur but also in the direct and indirect influences on the climate and environmental changes. Some marine biogenic active gases belong to greenhouse gases (CH4, N2O, VHCs and CO), and others would participate in chemical reactions in the atmosphere and control atmospheric chemical equilibrium and ozone concentration (VHCs and NMHCs). By contrast, DMS is a negative greenhouse effect gas. It will be rapidly oxidized to produce sulfate aerosol in the atmosphere and influence cloudy formation and the Earth's radiative budget. The present research status of marine biogenic active gases is reviewed and the sources and sinks, sea-to-air fluxes of DMS, CH4 and N2O as well as their influencing factors are summarized. Finally, some problems existing in the field and future research directions are presented.
2018, 40(10): 22-31.
doi: 10.3969/j.issn.0253-4193.2018.10.003
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This paper focuses on the background of rapid change in the west Arctic, investigates the marine ecological environmental responses to the Arctic rapid change on the aspects of the variation of nutrients, chlorophyll, phytoplankton community and sedimentary carbon buried in the western Arctic Ocean. Due to its special geographical location, the Arctic Ocean has become the most sensitive area for the regional response of climate change. In the last two decades, as the consequences of Arctic sea water temperature rises, rapid sea ice melting, light limitation disappearing, the upper layer of nutrients are fully utilized, chlorophyll increasing and chlorophyll maximum layer moves down and expands to the north, and the marine biological pump is running more efficiently. In addition to the ice algae, which once played an important role in the Arctic ecosystem, organic carbon from photosynthesis such as diatom has aslo gradually increased in the water column and buried in sediments. The increase in primary productivity in the western Arctic not only increases carbon sink in the sediment, but also provides more food sources for marine ecosystems.
This paper focuses on the background of rapid change in the west Arctic, investigates the marine ecological environmental responses to the Arctic rapid change on the aspects of the variation of nutrients, chlorophyll, phytoplankton community and sedimentary carbon buried in the western Arctic Ocean. Due to its special geographical location, the Arctic Ocean has become the most sensitive area for the regional response of climate change. In the last two decades, as the consequences of Arctic sea water temperature rises, rapid sea ice melting, light limitation disappearing, the upper layer of nutrients are fully utilized, chlorophyll increasing and chlorophyll maximum layer moves down and expands to the north, and the marine biological pump is running more efficiently. In addition to the ice algae, which once played an important role in the Arctic ecosystem, organic carbon from photosynthesis such as diatom has aslo gradually increased in the water column and buried in sediments. The increase in primary productivity in the western Arctic not only increases carbon sink in the sediment, but also provides more food sources for marine ecosystems.
2018, 40(10): 32-41.
doi: 10.3969/j.issn.0253-4193.2018.10.004
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Isotopes are unique in determining the source of material, indicating the path of biogeochemical cycle, and quantifying the rate of biogeochemical processes in marine environments. In this paper, stable isotopes (13C, 15N, 18O) and radionuclides (14C, 234Th, 232Th, 230Th, 228Th, 210Po, 210Pb, 137Cs, 226Ra, 228Ra, 224Ra, 223Ra) commonly used in coastal eco-environmental studies were targeted to reveal the source of marine organic matter, structure of food web, mechanism of coastal hypoxia, nitrogen cyclic processes, particle dynamics, submarine groundwater input, organic geochemical processes, sedimentary chronology, etc. We focused on summarizing recent progresses of their applications in the study of China coastal seas. With the start and development of economy, the eco-environments of China coastal seas have undergone significant changes in the past one hundred years. The evolution of eutrophication and sedimentary dynamics revealed by isotopes indicated that the eco-environment of China coastal seas has experienced persistent changes since the 1950s. Especially in the past 20-30 years, the changes have been dramatic, reflecting that human activities are the main driving force for the changes. In the future, it is need to study the response characteristics, variation rates and mechanisms of coastal eco-environmental changes through the development of new isotope techniques and their widely applications. In this way, we will be able to systematically grasp the temporal and spatial changes of the coastal ecosystem.
Isotopes are unique in determining the source of material, indicating the path of biogeochemical cycle, and quantifying the rate of biogeochemical processes in marine environments. In this paper, stable isotopes (13C, 15N, 18O) and radionuclides (14C, 234Th, 232Th, 230Th, 228Th, 210Po, 210Pb, 137Cs, 226Ra, 228Ra, 224Ra, 223Ra) commonly used in coastal eco-environmental studies were targeted to reveal the source of marine organic matter, structure of food web, mechanism of coastal hypoxia, nitrogen cyclic processes, particle dynamics, submarine groundwater input, organic geochemical processes, sedimentary chronology, etc. We focused on summarizing recent progresses of their applications in the study of China coastal seas. With the start and development of economy, the eco-environments of China coastal seas have undergone significant changes in the past one hundred years. The evolution of eutrophication and sedimentary dynamics revealed by isotopes indicated that the eco-environment of China coastal seas has experienced persistent changes since the 1950s. Especially in the past 20-30 years, the changes have been dramatic, reflecting that human activities are the main driving force for the changes. In the future, it is need to study the response characteristics, variation rates and mechanisms of coastal eco-environmental changes through the development of new isotope techniques and their widely applications. In this way, we will be able to systematically grasp the temporal and spatial changes of the coastal ecosystem.
2018, 40(10): 42-50.
doi: 10.3969/j.issn.0253-4193.2018.10.005
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N2 fixation plays an essential role in marine biogeochemical cycles by supplying new N. Stable isotope tracer (15N2) assay has been considered as the best approach for measuring in situ N2 fixation rate. Introducing 15N2 in an efficient and clean way, and precisely determining the isotopic enrichment level in the incubation system, is thus fundamental for obtaining true rates. In this study, we show that modified bubble treatment is a recommended practice in introducing 15N2. It can create 15N atomic abundance of substrate N2 in the incubation bottle higher than 10%. Such enrichment is twice higher when compared with gas pre-dissolution treatment. Moreover, modified bubble treatment is featured by much lowered risk of trace metal contamination and less time/labor consuming. We propose that the modified bubble method coupled to stable isotope mass spectrometry should be widely used in measuring N2 fixation rate in aquatic environments.
N2 fixation plays an essential role in marine biogeochemical cycles by supplying new N. Stable isotope tracer (15N2) assay has been considered as the best approach for measuring in situ N2 fixation rate. Introducing 15N2 in an efficient and clean way, and precisely determining the isotopic enrichment level in the incubation system, is thus fundamental for obtaining true rates. In this study, we show that modified bubble treatment is a recommended practice in introducing 15N2. It can create 15N atomic abundance of substrate N2 in the incubation bottle higher than 10%. Such enrichment is twice higher when compared with gas pre-dissolution treatment. Moreover, modified bubble treatment is featured by much lowered risk of trace metal contamination and less time/labor consuming. We propose that the modified bubble method coupled to stable isotope mass spectrometry should be widely used in measuring N2 fixation rate in aquatic environments.
2018, 40(10): 51-60.
doi: 10.3969/j.issn.0253-4193.2018.10.006
Abstract:
The deep-sea benthic community in the Yap Trench is highly food limited, with low biomass but high biodiversity. To investigate the food resources and trophic levels of the benthic community in the Yap Trench, stable carbon and nitrogen isotope ratios of phytoplankton, zooplankton, sedimentary organic matter and megabenthos (include Porifera, Holothuroidea, ophiuroidea, Asteroidea, Actiniaria, Gammaridea) were analyzed. The phytoplankton and zooplankton in the euphotic zone of the Yap Trench is the original food resources for the benthic community. However, the δ13C and δ15N values of phytoplankton[δ13C=(-22.8±0.4)‰,δ15N=(5.4±0.4)‰] and zooplankton[δ13C=(-21.8±0.8)‰,δ15N=(6.8±0.2)‰] were significantly different from those of mega benthos (δ13C values ranged from -20.1‰ to -16.8‰,δ15N values ranged from 11.9‰ to 17.9‰), indicating the organic matter produced in the surface water had been modified by zooplankton assimilation and bacteriological degradation during sinking. No significant correlation between δ13C and δ15N values of benthic tissue was found, indicating differential preference of organic matter for benthos. Trophic levels of specific deep-sea consumers were calculated, which showed the trophic level of Porifera was higher (3.4-4.7) than those of other benthos, including Gammaridea (2.9-3.3), Actiniaria (3.1), Holothuroidea (3.3-3.6), Ophiuroidea (3.4-3.5) and Asteroidea (3.2-3.7). It implied that different benthic feeders had a variety of feeding strategies to get diversified food resources.
The deep-sea benthic community in the Yap Trench is highly food limited, with low biomass but high biodiversity. To investigate the food resources and trophic levels of the benthic community in the Yap Trench, stable carbon and nitrogen isotope ratios of phytoplankton, zooplankton, sedimentary organic matter and megabenthos (include Porifera, Holothuroidea, ophiuroidea, Asteroidea, Actiniaria, Gammaridea) were analyzed. The phytoplankton and zooplankton in the euphotic zone of the Yap Trench is the original food resources for the benthic community. However, the δ13C and δ15N values of phytoplankton[δ13C=(-22.8±0.4)‰,δ15N=(5.4±0.4)‰] and zooplankton[δ13C=(-21.8±0.8)‰,δ15N=(6.8±0.2)‰] were significantly different from those of mega benthos (δ13C values ranged from -20.1‰ to -16.8‰,δ15N values ranged from 11.9‰ to 17.9‰), indicating the organic matter produced in the surface water had been modified by zooplankton assimilation and bacteriological degradation during sinking. No significant correlation between δ13C and δ15N values of benthic tissue was found, indicating differential preference of organic matter for benthos. Trophic levels of specific deep-sea consumers were calculated, which showed the trophic level of Porifera was higher (3.4-4.7) than those of other benthos, including Gammaridea (2.9-3.3), Actiniaria (3.1), Holothuroidea (3.3-3.6), Ophiuroidea (3.4-3.5) and Asteroidea (3.2-3.7). It implied that different benthic feeders had a variety of feeding strategies to get diversified food resources.
2018, 40(10): 61-70.
doi: 10.3969/j.issn.0253-4193.2018.10.007
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The estuarine distributions of salinity and nutrients (ammonium, nitrite, nitrate, and phosphate) measured in May 2012 and October 2017 were used to study the sources and assimilation of phosphate and the processes that control phosphate distributions within the Xiangshan Bay. In the upper bay, the highest phosphate concentrations observed during both surveys indicates a significant source of phosphate in this area, which was likely from the domestic sewage or/and mariculture. In the lower bay, the distributions of salinity, nitrate and phosphate suggest that phosphate in this area was likely from the Changjiang River and Qiantangjiang River. In addition, the different distribution patterns of nitrate and phosphate in the Fodu and Niubishan channels indicate a local input of phosphate. In the upper bay, phosphate distributions were controlled mainly by the mixing of waters from the upper bay and the lower bay and phytoplankton assimilation. Significant phosphate consumption was observed in the upper bay. In May 2012 and October 2017, phosphate was removed by~20% and~9%, respectively, in the upper bay compared to the calculated mixing line. The phosphate concentration has been found to increase by more than 50% compared to that in the same season of 2002 to 2005, and N/P ratio decreased significantly, which would result in variation of algal bloom species and occurrence of more serious harmful algal bloom.
The estuarine distributions of salinity and nutrients (ammonium, nitrite, nitrate, and phosphate) measured in May 2012 and October 2017 were used to study the sources and assimilation of phosphate and the processes that control phosphate distributions within the Xiangshan Bay. In the upper bay, the highest phosphate concentrations observed during both surveys indicates a significant source of phosphate in this area, which was likely from the domestic sewage or/and mariculture. In the lower bay, the distributions of salinity, nitrate and phosphate suggest that phosphate in this area was likely from the Changjiang River and Qiantangjiang River. In addition, the different distribution patterns of nitrate and phosphate in the Fodu and Niubishan channels indicate a local input of phosphate. In the upper bay, phosphate distributions were controlled mainly by the mixing of waters from the upper bay and the lower bay and phytoplankton assimilation. Significant phosphate consumption was observed in the upper bay. In May 2012 and October 2017, phosphate was removed by~20% and~9%, respectively, in the upper bay compared to the calculated mixing line. The phosphate concentration has been found to increase by more than 50% compared to that in the same season of 2002 to 2005, and N/P ratio decreased significantly, which would result in variation of algal bloom species and occurrence of more serious harmful algal bloom.
2018, 40(10): 71-83.
doi: 10.3969/j.issn.0253-4193.2018.10.008
Abstract:
Antimicrobial agents, which are widely used by humans and animals, could enter the marine environment with runoff and point source discharge. The characteristics of distribution, migration and the risk of ecological environment of antimicrobial agents have attracted much attention. Studying the marine biogeochemical behavior of antibiotics is significant for the sustainable utilization of marine resources and environment. The solid phase extraction-high efficiency liquid chromatography-multireaction monitoring scanning mode-mass spectrometry (SPE-HPLC-MRM-MSMS) method was used to analyze the concentration and distribution characteristics of typical antibiotics (6 categories, 20 types) in the surface water of the Jiaozhou Bay. The results showed that the total concentration of the antibiotic pollutions ranged from 12.59 ng/L to 147.69 ng/L. The pollution of Tetracycline in the surface water was the most prominent with the highest average concentration of 41.32 ng/L, followed by Lincomycin (8.56 ng/L), Quinolones (2.62 ng/L), Sulfonamides (1.15 ng/L), Macrolides (0.82 ng/L), and Cephalosporins (0.35 ng/L). Cephalosporins and Lincomycin were firstly detected in marine environment of China and the highest concentration of lincomycin reached to 96.40 ng/L. The concentation of antibiotics in the surface water decreased from inshore area to the offshore area. Within the bay, the eastern district showed higher concentrations of antibiotics compared with the western district. The inshore area in east inner bay (station S5) showed the highest average concentration. The proportions of antibiotics for human use, veterinary use and human and animal sharing use were 52.0%, 30.2% and 17.8%,respectively, while antibiotics for human use were the main source of antibiotic contamination in the Jiaozhou Bay. The results of ecological risk assessment showed that the residual Ofloxacin and Lincomycin in the surface water of the Jiaozhou Bay have high ecological risk to the sensitive species. Station S5 was in high risk and monitoring should be emphasized to reduce the damag/>
Antimicrobial agents, which are widely used by humans and animals, could enter the marine environment with runoff and point source discharge. The characteristics of distribution, migration and the risk of ecological environment of antimicrobial agents have attracted much attention. Studying the marine biogeochemical behavior of antibiotics is significant for the sustainable utilization of marine resources and environment. The solid phase extraction-high efficiency liquid chromatography-multireaction monitoring scanning mode-mass spectrometry (SPE-HPLC-MRM-MSMS) method was used to analyze the concentration and distribution characteristics of typical antibiotics (6 categories, 20 types) in the surface water of the Jiaozhou Bay. The results showed that the total concentration of the antibiotic pollutions ranged from 12.59 ng/L to 147.69 ng/L. The pollution of Tetracycline in the surface water was the most prominent with the highest average concentration of 41.32 ng/L, followed by Lincomycin (8.56 ng/L), Quinolones (2.62 ng/L), Sulfonamides (1.15 ng/L), Macrolides (0.82 ng/L), and Cephalosporins (0.35 ng/L). Cephalosporins and Lincomycin were firstly detected in marine environment of China and the highest concentration of lincomycin reached to 96.40 ng/L. The concentation of antibiotics in the surface water decreased from inshore area to the offshore area. Within the bay, the eastern district showed higher concentrations of antibiotics compared with the western district. The inshore area in east inner bay (station S5) showed the highest average concentration. The proportions of antibiotics for human use, veterinary use and human and animal sharing use were 52.0%, 30.2% and 17.8%,respectively, while antibiotics for human use were the main source of antibiotic contamination in the Jiaozhou Bay. The results of ecological risk assessment showed that the residual Ofloxacin and Lincomycin in the surface water of the Jiaozhou Bay have high ecological risk to the sensitive species. Station S5 was in high risk and monitoring should be emphasized to reduce the damag/>
2018, 40(10): 84-95.
doi: 10.3969/j.issn.0253-4193.2018.10.009
Abstract:
Concentrations distributions of dimethylsulfide (DMS), dimethylsulfoniopropionate (DMSP) and dimethylsulfoxide (DMSO) as well as their influencing factors were studied in the Yellow Sea and Bohai Sea from August to September, 2015. The rates of biological production and microbial consumption, photochemical oxidation and sea-to-air diffusion of DMS were also determined, to evaluate the migration and transformation rates of DMS. The mean concentrations of DMS, dissolved DMSP (DMSPd), particulate DMSP (DMSPp), dissolved DMSO (DMSOd) and particulate DMSO (DMSOp) in the surface water were (6.12±3.01) nmol/L, (6.03±3.45) nmol/L, (19.47±9.15) nmol/L, (16.85±8.34) nmol/L and (14.37±7.47) nmol/L, respectively. Their distributions presented similar tendency to decrease from inshore to offshore, from the surface to the bottom. The concentrations of DMS, DMSPd and DMSOp were significantly correlated with the concentrations of Chl a. The order of photochemical oxidation rates of DMS was kUVA > kUVB > kvis in the surface water, and UVA accounted for 70.8% of the total photolysis. The average contribution of microbial consumption, photochemical oxidation and sea-to-air diffusion were 32.4%, 34.5% and 33.1%, respectively, which were basically equivalent to DMS removal. In addition, the sea-to-air flux of DMS ranged from 0.79 μmol/(m2·d) to 48.45 μmol/(m2·d) from the Yellow Sea and the Bohai Sea, with the mean value of (11.87±11.35) μmol/(m2·d).
Concentrations distributions of dimethylsulfide (DMS), dimethylsulfoniopropionate (DMSP) and dimethylsulfoxide (DMSO) as well as their influencing factors were studied in the Yellow Sea and Bohai Sea from August to September, 2015. The rates of biological production and microbial consumption, photochemical oxidation and sea-to-air diffusion of DMS were also determined, to evaluate the migration and transformation rates of DMS. The mean concentrations of DMS, dissolved DMSP (DMSPd), particulate DMSP (DMSPp), dissolved DMSO (DMSOd) and particulate DMSO (DMSOp) in the surface water were (6.12±3.01) nmol/L, (6.03±3.45) nmol/L, (19.47±9.15) nmol/L, (16.85±8.34) nmol/L and (14.37±7.47) nmol/L, respectively. Their distributions presented similar tendency to decrease from inshore to offshore, from the surface to the bottom. The concentrations of DMS, DMSPd and DMSOp were significantly correlated with the concentrations of Chl a. The order of photochemical oxidation rates of DMS was kUVA > kUVB > kvis in the surface water, and UVA accounted for 70.8% of the total photolysis. The average contribution of microbial consumption, photochemical oxidation and sea-to-air diffusion were 32.4%, 34.5% and 33.1%, respectively, which were basically equivalent to DMS removal. In addition, the sea-to-air flux of DMS ranged from 0.79 μmol/(m2·d) to 48.45 μmol/(m2·d) from the Yellow Sea and the Bohai Sea, with the mean value of (11.87±11.35) μmol/(m2·d).
2018, 40(10): 96-109.
doi: 10.3969/j.issn.0253-4193.2018.10.010
Abstract:
The concentrations of four volatile halocarbons (VHCs) including CFC-11, CH3I, CH3CCl3 and C2Cl4 in the seawater of the Changjiang River Estuary and its adjacent marine area were determined by purge and trap-chromatography during the summer of 2016. Furthermore, CFC-11, CH3I, and C2Cl4 concentrations in the marine atmosphere were also determined. The results showed that the concentrations of four VHCs in the coastal waters were higher than those in the open sea because of the influence of the Changjiang River runoff. In the vertical distributions, the four VHCs had a common feature with the maxima appearing in the 10 m layer. The concentrations of the VHCs were high inside the estuary (Section C) and low outside (Section A6). The distributions of the VHCs were influenced by water mass, biological production and terrestrial input. No correlation was observed between CH3I and chlorophyll a (Chl a) concentrations, while CFC-11 had significant positive correlations with CH3I and C2Cl4(p<0.01), indicating that the influence of anthropogenic sources on CH3I was greater than that of natural sources. In the atmosphere, the concentration distributions of CFC-11, CH3I and C2Cl4 showed a downtrend from inshore to offshore regions. The concentration of CFC-11 was lower than the global average, indicating that the emission of CFC-11 in China has been effectively controlled. The results of backward trajectory showed that the diffusion and transport of land-based pollutants from the nearshore was an important source of three kinds of VHCs in the marine atmosphere. The mean sea-to-air flux of CFC-11, CH3I and C2Cl4 were respectively 24.99 nmol/(m2·d), 7.80 nmol/(m2·d), 1.55 nmol/(m2·d), which indicated that the Changjiang River Estuary and its adjacent marine area acted as a source of atmospheric CFC-11, CH3I and C2Cl4 in summer.
The concentrations of four volatile halocarbons (VHCs) including CFC-11, CH3I, CH3CCl3 and C2Cl4 in the seawater of the Changjiang River Estuary and its adjacent marine area were determined by purge and trap-chromatography during the summer of 2016. Furthermore, CFC-11, CH3I, and C2Cl4 concentrations in the marine atmosphere were also determined. The results showed that the concentrations of four VHCs in the coastal waters were higher than those in the open sea because of the influence of the Changjiang River runoff. In the vertical distributions, the four VHCs had a common feature with the maxima appearing in the 10 m layer. The concentrations of the VHCs were high inside the estuary (Section C) and low outside (Section A6). The distributions of the VHCs were influenced by water mass, biological production and terrestrial input. No correlation was observed between CH3I and chlorophyll a (Chl a) concentrations, while CFC-11 had significant positive correlations with CH3I and C2Cl4(p<0.01), indicating that the influence of anthropogenic sources on CH3I was greater than that of natural sources. In the atmosphere, the concentration distributions of CFC-11, CH3I and C2Cl4 showed a downtrend from inshore to offshore regions. The concentration of CFC-11 was lower than the global average, indicating that the emission of CFC-11 in China has been effectively controlled. The results of backward trajectory showed that the diffusion and transport of land-based pollutants from the nearshore was an important source of three kinds of VHCs in the marine atmosphere. The mean sea-to-air flux of CFC-11, CH3I and C2Cl4 were respectively 24.99 nmol/(m2·d), 7.80 nmol/(m2·d), 1.55 nmol/(m2·d), which indicated that the Changjiang River Estuary and its adjacent marine area acted as a source of atmospheric CFC-11, CH3I and C2Cl4 in summer.
2018, 40(10): 110-118.
doi: 10.3969/j.issn.0253-4193.2018.10.011
Abstract:
In order to study the characteristics of the release of biogenic sulfur of Ulva prolifera, laboratory simulations were conducted on the Ulva prolifera collected in the middle and late green tides of the Yellow Sea. The effects of different temperatures on the release of biogenic sulfides from Ulva prolifera were investigated. The results are as follows:under the condition of 10-25℃, the increase of temperature can promote the decline of Ulva prolifera. The average release rate of DMS ranged from 2.79-150.70 nmol/(L·g·d), the average release rate of DMSP ranged from 2.16-113.26 nmol/(L·g·d). On the other hand, the high temperature can accelerate the releasing rates of dimethysulfide (DMS) and dimethylsulfonionpropionate (DMSP), and increase the releasing amount. The maximum average release rate of DMS is increased by about 60% at 25℃ compared with 10℃, and the concentration of DMS in culture fluid is increased by 2-3 times. The concentration of DMS and DMSP collected in the culture fluid of Ulva prolifera at the end of green tide was increased compared with that of Ulva prolifera taken during the mid-green tide. The highest concentration of DMS in the culture fluid at the end of green tide of Ulva prolifera was 418.41 nmol/L, which was about 4 times of that in the middle period. The highest concentration of DMS in DMSP was 316.14 nmol/L, which was 3 times of the middle period. The outbreak of the green tide of the Enteromorpha will affect the circulation of the sulfur system in the water body and thus affect the ecological environment of the sea area.
In order to study the characteristics of the release of biogenic sulfur of Ulva prolifera, laboratory simulations were conducted on the Ulva prolifera collected in the middle and late green tides of the Yellow Sea. The effects of different temperatures on the release of biogenic sulfides from Ulva prolifera were investigated. The results are as follows:under the condition of 10-25℃, the increase of temperature can promote the decline of Ulva prolifera. The average release rate of DMS ranged from 2.79-150.70 nmol/(L·g·d), the average release rate of DMSP ranged from 2.16-113.26 nmol/(L·g·d). On the other hand, the high temperature can accelerate the releasing rates of dimethysulfide (DMS) and dimethylsulfonionpropionate (DMSP), and increase the releasing amount. The maximum average release rate of DMS is increased by about 60% at 25℃ compared with 10℃, and the concentration of DMS in culture fluid is increased by 2-3 times. The concentration of DMS and DMSP collected in the culture fluid of Ulva prolifera at the end of green tide was increased compared with that of Ulva prolifera taken during the mid-green tide. The highest concentration of DMS in the culture fluid at the end of green tide of Ulva prolifera was 418.41 nmol/L, which was about 4 times of that in the middle period. The highest concentration of DMS in DMSP was 316.14 nmol/L, which was 3 times of the middle period. The outbreak of the green tide of the Enteromorpha will affect the circulation of the sulfur system in the water body and thus affect the ecological environment of the sea area.
2018, 40(10): 119-130.
doi: 10.3969/j.issn.0253-4193.2018.10.012
Abstract:
The grain size of sediments, total organic carbon (TOC), total nitrogen (TN), ratio of TOC/TN, and abundance of stable isotope (δ13C, δ15N) were analyzed in sediments of the Daya Bay. Combining with the sedimentary chronology information and end-member model, the sediment records and responses for anthropogenic activities of organic matter in the Daya Bay during recent one hundred years were discussed. The results showed that the sediment characteristics of the Daya Bay changed significantly from late 1970s to early 1980s. Before that time, TOC, TN, δ13C and δ15N were stable, and the ratio of terrestrial and marine organic carbon was maintained at 3:7. After then, however, the content of TOC and TN has been significantly increased, and TOC/TN has continued to decline. From 1980 to 2000 and from 2010 to date, there has been increases of terrestrial organic carbon and decreases of marine organic carbon. The aforementioned variations of sediment characteristics in the Daya Bay indicated the marine environment has undergone significant changes since late 1970s to early 1980. During the recent 20 years, the GDP had significant positive correlations with TN and δ15N, and had significant negative correlation with the TOC/TN. These finding proved the rapid developments of economy, aquaculture, and population around the Daya Bay were the controlling factors for the ecological environment change. Future research should pay close attention to the influence of human activities on the ecological environment of coastal bays, and reasonably establish laws and regulations to protect and repair the ecological environment of them.
The grain size of sediments, total organic carbon (TOC), total nitrogen (TN), ratio of TOC/TN, and abundance of stable isotope (δ13C, δ15N) were analyzed in sediments of the Daya Bay. Combining with the sedimentary chronology information and end-member model, the sediment records and responses for anthropogenic activities of organic matter in the Daya Bay during recent one hundred years were discussed. The results showed that the sediment characteristics of the Daya Bay changed significantly from late 1970s to early 1980s. Before that time, TOC, TN, δ13C and δ15N were stable, and the ratio of terrestrial and marine organic carbon was maintained at 3:7. After then, however, the content of TOC and TN has been significantly increased, and TOC/TN has continued to decline. From 1980 to 2000 and from 2010 to date, there has been increases of terrestrial organic carbon and decreases of marine organic carbon. The aforementioned variations of sediment characteristics in the Daya Bay indicated the marine environment has undergone significant changes since late 1970s to early 1980. During the recent 20 years, the GDP had significant positive correlations with TN and δ15N, and had significant negative correlation with the TOC/TN. These finding proved the rapid developments of economy, aquaculture, and population around the Daya Bay were the controlling factors for the ecological environment change. Future research should pay close attention to the influence of human activities on the ecological environment of coastal bays, and reasonably establish laws and regulations to protect and repair the ecological environment of them.
2018, 40(10): 131-142.
doi: 10.3969/j.issn.0253-4193.2018.10.013
Abstract:
Grain size and AMS14C dating in the sediment of Kuroshio mainstream, eastern of Taiwan, were determined to investigate the sedimentary environmental change of the research area for the past millennium. It made use of total organic carbon (TOC) and carbon stable isotope compositions in organic matter (δ13C) of sediments to estimate the sea-derived carbon contents. The change of marine primary productivity and the response of climate change in the research area for the past millennium were discussed based on the above study for the first time. The results showed that the sedimentary environment of the research area was relatively stable, with an average sedimentary rate of 34.44 cm/ka. In addition, TOC and total nitrogen (TN) contents of the sediments in Kuroshio mainstream were mainly influenced by rivers input of eastern Taiwan, settlement process of marine primary productivity, diagenesis and grain-size effect. TOC of research area sediments was mainly marine autogenic and was minor terrigenous input based on the estimation result of sea-derived carbon contents, which is about 40.02%-73.88% of organic matter in the sediments was marine autogenic. Meanwhile, the sedimentary records in Kuroshio mainstream for the past millennium well were reflected three climate periods, which is Medieval Warm Period (MWP), Little Ice Period (LIP) and Modern Period (MP). During 1150-1420, the contents of TOC, TN and sea-derived carbon of sediments in the research area were rising slowly, and the marine primary productivity was rising affected by the relatively high sea surface temperature (SST) in MWP. During 1500-1840, the difference of variation trend between TOC and sea-derived carbon contents reflected the temperature and rainfall features in LIA of the research area. On the one hand, relatively low sea-derived carbon contents and marine primary productivity were affected by relatively low SST and less Asian continental dust input during 1600-1750. Relatively high TOC contents in the research area sediments during 1500-1850 was related to more sediment input, which was caused by increased rainfall of Taiwan in LIA and stronger rivers input of eastern Taiwan. In the MP, SST in the research area was gradually increased, but the intensity of the East Asian monsoon and the precipitation fluctuated rapidly, which is reflected in the rapid fluctuation of the median diameter (D50), TOC and TN contents during 1930-1950 and 1970.
Grain size and AMS14C dating in the sediment of Kuroshio mainstream, eastern of Taiwan, were determined to investigate the sedimentary environmental change of the research area for the past millennium. It made use of total organic carbon (TOC) and carbon stable isotope compositions in organic matter (δ13C) of sediments to estimate the sea-derived carbon contents. The change of marine primary productivity and the response of climate change in the research area for the past millennium were discussed based on the above study for the first time. The results showed that the sedimentary environment of the research area was relatively stable, with an average sedimentary rate of 34.44 cm/ka. In addition, TOC and total nitrogen (TN) contents of the sediments in Kuroshio mainstream were mainly influenced by rivers input of eastern Taiwan, settlement process of marine primary productivity, diagenesis and grain-size effect. TOC of research area sediments was mainly marine autogenic and was minor terrigenous input based on the estimation result of sea-derived carbon contents, which is about 40.02%-73.88% of organic matter in the sediments was marine autogenic. Meanwhile, the sedimentary records in Kuroshio mainstream for the past millennium well were reflected three climate periods, which is Medieval Warm Period (MWP), Little Ice Period (LIP) and Modern Period (MP). During 1150-1420, the contents of TOC, TN and sea-derived carbon of sediments in the research area were rising slowly, and the marine primary productivity was rising affected by the relatively high sea surface temperature (SST) in MWP. During 1500-1840, the difference of variation trend between TOC and sea-derived carbon contents reflected the temperature and rainfall features in LIA of the research area. On the one hand, relatively low sea-derived carbon contents and marine primary productivity were affected by relatively low SST and less Asian continental dust input during 1600-1750. Relatively high TOC contents in the research area sediments during 1500-1850 was related to more sediment input, which was caused by increased rainfall of Taiwan in LIA and stronger rivers input of eastern Taiwan. In the MP, SST in the research area was gradually increased, but the intensity of the East Asian monsoon and the precipitation fluctuated rapidly, which is reflected in the rapid fluctuation of the median diameter (D50), TOC and TN contents during 1930-1950 and 1970.
2018, 40(10): 143-157.
doi: 10.3969/j.issn.0253-4193.2018.10.014
Abstract:
This is the first study of variations of concentrations of methane and precursor of dimethylsulfide (DMS)-dimethylsulfoniopropionate (DMSP) from surface to hadal seawater in the northern area of the Yap Trench in the western Pacific Ocean. The results showed that the concentration of methane seawater of the Yap Trench ranged from 1.49 to 3.87 nmol/L. The concentration of methane was highest in photic water of the trench, and the maximum value occurred in the subsurface layer. Average concentration of methane was the lowest in the oxygen minimum layer of the trench. There was a certain degree increase of concentration of methane in the 500-1 000 m water layer of the trench. Below 1 000 m depth, concentration of methane kept increasing to the bottom water. The vertical variation of the average concentration of DMSPd and DMSPt showed increasing and then decreasing trends with depth. The average concentration of DMSPp showed fluctuation variation trend, with highest value in the mesopelagic layer. The vertical variations of concentraions of methane and DMSP in the Yap Trench was controlled by various factors, including plankton, microorganisms, light, temperature, pressure, ocean circulation, and etc. In photic seawater of the trench, the correlation between concentrations of CH4 and DMSPd, DMSPp and DMSPt was negative, and from 200 m to bottom seawater, the concentration of CH4 and DMSP had positive correlation, indicating light condition was the critical factor controlling the correlation between concentrations of methane and DMSPd, DMSPp and DMSPt.
This is the first study of variations of concentrations of methane and precursor of dimethylsulfide (DMS)-dimethylsulfoniopropionate (DMSP) from surface to hadal seawater in the northern area of the Yap Trench in the western Pacific Ocean. The results showed that the concentration of methane seawater of the Yap Trench ranged from 1.49 to 3.87 nmol/L. The concentration of methane was highest in photic water of the trench, and the maximum value occurred in the subsurface layer. Average concentration of methane was the lowest in the oxygen minimum layer of the trench. There was a certain degree increase of concentration of methane in the 500-1 000 m water layer of the trench. Below 1 000 m depth, concentration of methane kept increasing to the bottom water. The vertical variation of the average concentration of DMSPd and DMSPt showed increasing and then decreasing trends with depth. The average concentration of DMSPp showed fluctuation variation trend, with highest value in the mesopelagic layer. The vertical variations of concentraions of methane and DMSP in the Yap Trench was controlled by various factors, including plankton, microorganisms, light, temperature, pressure, ocean circulation, and etc. In photic seawater of the trench, the correlation between concentrations of CH4 and DMSPd, DMSPp and DMSPt was negative, and from 200 m to bottom seawater, the concentration of CH4 and DMSP had positive correlation, indicating light condition was the critical factor controlling the correlation between concentrations of methane and DMSPd, DMSPp and DMSPt.
2018, 40(10): 158-166.
doi: 10.3969/j.issn.0253-4193.2018.10.015
Abstract:
The analytical techniques for trace elements and isotopic ratios in foraminifera shells from deep-sea sediments have been well developed. However, few papers have reported the in situ elemental analysis from estuaries and coastal sediments. In this study, an in situ microanalytical method of elements/Ca for foraminifera (Florilus decors) shells from sediment off the Changjiang River Estuary via using Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) was explored. We tested a series of laser ablation conditions (e.g., carrier flow, uence, laser spot size, repetition rate) to optimizing the analytical procedure. F. decors shells, collected from the sediment off Changjiang River Estuary in July 2016, were analyzed based on the procedure. We found Mg/Ca and Sr/Ca ratios on the foraminifera shells had no significant difference in different positions, but Mn/Ca had relative discrete trends, which might be caused by the foram living aquatic environment.
The analytical techniques for trace elements and isotopic ratios in foraminifera shells from deep-sea sediments have been well developed. However, few papers have reported the in situ elemental analysis from estuaries and coastal sediments. In this study, an in situ microanalytical method of elements/Ca for foraminifera (Florilus decors) shells from sediment off the Changjiang River Estuary via using Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) was explored. We tested a series of laser ablation conditions (e.g., carrier flow, uence, laser spot size, repetition rate) to optimizing the analytical procedure. F. decors shells, collected from the sediment off Changjiang River Estuary in July 2016, were analyzed based on the procedure. We found Mg/Ca and Sr/Ca ratios on the foraminifera shells had no significant difference in different positions, but Mn/Ca had relative discrete trends, which might be caused by the foram living aquatic environment.
2018, 40(10): 167-179.
doi: 10.3969/j.issn.0253-4193.2018.10.016
Abstract:
The total organic carbon (TOC), total nitrogen (TN), stable carbon isotope (δ13C), grain size composition and specific surface area (SSA) in sediment cores from different water depths in the southern Yap Trench (West Pacific Ocean) were measured in order to study the differences of sources, distributions of sedimentary particles and influencing factors. The average TOC content and δ13C of Yap Trench sediments were around (0.34%±0.14%) and (-20.8‰±0.7‰), and the proportions of marine phytoplankton-, terrestrial soil- and vascular plant- derived organic carbon (OC) were (70%±3%), (22%±3%) and (8%±2%), respectively. No remarkable difference were found between these two sediment cores, which probably indicating lateral transportation was the major pathway of sediment inputs in the deeper Yap Trench. Due to stronger microbial activity and longer retention time of sedimentary particles, TOC and TN contents were pretty lower in deeper site, but no remarkable difference in δ13C value between two sites. The vertical variations of TN content, SSA, grain size composition and median grain size in the shallower site were more drastic than those in the deeper site, suggesting unstable sedimentary particle inputs and sedimentary environment in shallower trench slope region. Widespread distribution of basalt lava with much lower OC content and SSA and higher density in the shallower break area of trench slope, lead to poor correlations between particle size compositions and TOC content in shallower site. Oppositely, it showed significantly positive relationship between TOC content and silt% and negative relationship with clay% and sand% in deeper site. Generally, silt-sized sedimentary particle probably was the major carrier of OC in the Yap Trench, and SSA value was the most important factor affecting the vertical profile of sedimentary OC in the trench.
The total organic carbon (TOC), total nitrogen (TN), stable carbon isotope (δ13C), grain size composition and specific surface area (SSA) in sediment cores from different water depths in the southern Yap Trench (West Pacific Ocean) were measured in order to study the differences of sources, distributions of sedimentary particles and influencing factors. The average TOC content and δ13C of Yap Trench sediments were around (0.34%±0.14%) and (-20.8‰±0.7‰), and the proportions of marine phytoplankton-, terrestrial soil- and vascular plant- derived organic carbon (OC) were (70%±3%), (22%±3%) and (8%±2%), respectively. No remarkable difference were found between these two sediment cores, which probably indicating lateral transportation was the major pathway of sediment inputs in the deeper Yap Trench. Due to stronger microbial activity and longer retention time of sedimentary particles, TOC and TN contents were pretty lower in deeper site, but no remarkable difference in δ13C value between two sites. The vertical variations of TN content, SSA, grain size composition and median grain size in the shallower site were more drastic than those in the deeper site, suggesting unstable sedimentary particle inputs and sedimentary environment in shallower trench slope region. Widespread distribution of basalt lava with much lower OC content and SSA and higher density in the shallower break area of trench slope, lead to poor correlations between particle size compositions and TOC content in shallower site. Oppositely, it showed significantly positive relationship between TOC content and silt% and negative relationship with clay% and sand% in deeper site. Generally, silt-sized sedimentary particle probably was the major carrier of OC in the Yap Trench, and SSA value was the most important factor affecting the vertical profile of sedimentary OC in the trench.
2018, 40(10): 180-189.
doi: 10.3969/j.issn.0253-4193.2018.10.017
Abstract:
In order to issue the biogeochemistry of dissolved organic carbon (DOC) in the western Pacific Ocean, the absorbance and fluorescence spectrums of chromophoric dissolved organic matter (CDOM) were studied in the upper waters from November 2015 to January 2016. Results showed that, the absorbance coefficient a(320) of CDOM ranged at 0.01-1.07 m-1 with an average of 0.18 m-1. The higher a(320) were located in the 100-200 m water layers, while the lower values were in the surface water layers, which may due to the photochemical decomposition process. Parallel factor analysis was applied to analyze the three-dimensional fluorescence spectrum of CDOM, including one humic-like component of C2 (252(310) nm/405 nm) and two protein-like components of C1 (224(276 nm)/335 nm) and C3(224(260)nm/300 nm). The humic-like components accounted for 11%-22% in fluorescence intensity, while protein-like components dominated in 78%-89%. Protein-like components, which were composed of tryptophan-like and tyrosine-like compounds, contributed substantially to the fluorescence intensity. The higher CDOM fluorescence was observed in the boundaries between ocean currents and circulation formative regions. And oceanic currents controlled the general CDOM distribution in large scale in study area. In addition, positive relationships were discovered among the relative contents of CDOM, CDOM fluorescence, temperature, salinity, DO and nutrients in the upper water layers of the western Pacific Ocean. It was suggested that the CDOM production were more closely related with primary production in upper water layers.
In order to issue the biogeochemistry of dissolved organic carbon (DOC) in the western Pacific Ocean, the absorbance and fluorescence spectrums of chromophoric dissolved organic matter (CDOM) were studied in the upper waters from November 2015 to January 2016. Results showed that, the absorbance coefficient a(320) of CDOM ranged at 0.01-1.07 m-1 with an average of 0.18 m-1. The higher a(320) were located in the 100-200 m water layers, while the lower values were in the surface water layers, which may due to the photochemical decomposition process. Parallel factor analysis was applied to analyze the three-dimensional fluorescence spectrum of CDOM, including one humic-like component of C2 (252(310) nm/405 nm) and two protein-like components of C1 (224(276 nm)/335 nm) and C3(224(260)nm/300 nm). The humic-like components accounted for 11%-22% in fluorescence intensity, while protein-like components dominated in 78%-89%. Protein-like components, which were composed of tryptophan-like and tyrosine-like compounds, contributed substantially to the fluorescence intensity. The higher CDOM fluorescence was observed in the boundaries between ocean currents and circulation formative regions. And oceanic currents controlled the general CDOM distribution in large scale in study area. In addition, positive relationships were discovered among the relative contents of CDOM, CDOM fluorescence, temperature, salinity, DO and nutrients in the upper water layers of the western Pacific Ocean. It was suggested that the CDOM production were more closely related with primary production in upper water layers.
2018, 40(10): 190-199.
doi: 10.3969/j.issn.0253-4193.2018.10.018
Abstract:
Typical sea areas of Bohai Sea, Yellow Sea and East China Sea were selected, and the sediments were collected to simulate experiment on adsorption and desorption of urea. The Freundlich adsorption model and the Henry adsorption model were used to analyze the thermodynamic properties of urea adsorption on different sediment surfaces. The effect of temperature, particle size and organic matter content on the adsorption of urea on the surface of sediments was studied. The results showed that three typical stages, which were quick adsorption stage(0-5 h), slow adsorption stage (5-12 h) and equilibrium stage(after 12 h), were obviously showed in adsorption and desorption curves of urea on sediments. When the urea concentration is low, the sediment desorbs and releases urea, and the sediment adsorbs the urea in the overlying water when the urea concentration gradually increases. The adsorption capacity of urea from strong to weak is the Bohai Sea, East China Sea and Yellow Sea, which may be related to the types of sediments. The Freundlich equation and the Henry equation can accurately simulate the adsorption of urea by sediments. Temperature, particle size and organic matter content all affect the adsorption of urea on the sediments. With the increase of temperature, the adsorption of urea on the sediments becomes smaller. The smaller the particle size of sediments and the higher the organic matter content, the stronger the adsorption capacity. Therefore, when revealing the environmental behavior of urea on the sediment surface, it is necessary to fully consider the influence of the above factors.
Typical sea areas of Bohai Sea, Yellow Sea and East China Sea were selected, and the sediments were collected to simulate experiment on adsorption and desorption of urea. The Freundlich adsorption model and the Henry adsorption model were used to analyze the thermodynamic properties of urea adsorption on different sediment surfaces. The effect of temperature, particle size and organic matter content on the adsorption of urea on the surface of sediments was studied. The results showed that three typical stages, which were quick adsorption stage(0-5 h), slow adsorption stage (5-12 h) and equilibrium stage(after 12 h), were obviously showed in adsorption and desorption curves of urea on sediments. When the urea concentration is low, the sediment desorbs and releases urea, and the sediment adsorbs the urea in the overlying water when the urea concentration gradually increases. The adsorption capacity of urea from strong to weak is the Bohai Sea, East China Sea and Yellow Sea, which may be related to the types of sediments. The Freundlich equation and the Henry equation can accurately simulate the adsorption of urea by sediments. Temperature, particle size and organic matter content all affect the adsorption of urea on the sediments. With the increase of temperature, the adsorption of urea on the sediments becomes smaller. The smaller the particle size of sediments and the higher the organic matter content, the stronger the adsorption capacity. Therefore, when revealing the environmental behavior of urea on the sediment surface, it is necessary to fully consider the influence of the above factors.
2018, 40(10): 200-208.
doi: 10.3969/j.issn.0253-4193.2018.10.019
Abstract:
Based on the date of cruises that carried out in the Yellow Sea and the Bohai Sea during the summer of 2016. The concentration and special distribution of particulate organic carbon (POC) were analyzed and combined with the distribution of salinity, chlorophyll and POC/PON, POC/Chl a the source of POC were analyzed. Results showed that the average concentration of POC in the Bohai Sea, the North Yellow Sea and the South Yellow Sea were (500.2±226.5)μg/L, (358.2±101.5)μg/L, (321.0±158.1)μg/L,respectively. The concentration of POC in the Bohai Sea was higher than that in the Yellow Sea. The highest POC concentration was in the coastal zones and it tended to decrease toward the far shore on the whole. POC/PON was 8.89,POC/Chl a was 182.52 in the surface layer, POC/PON was 8.87, POC/Chl a was 179.56 in the middle layer, POC/PON was 9.41, POC/Chl a was 178.80 in the bottom layer. The high value of POC/PON and POC/Chl a had a certain relationship with the rotten of Enteromorpha prolifera. The result of correlation analysis showed salinity, total suspended matter and Chl a had a significant relationship with POC in the Bohai Sea which were the main factors influencing the distribution of POC in the Bohai Sea. In addition to the surface POC in the South Yellow Sea, there is no significant correlation between POC and salinity, total suspended matter, chlorophyll in other layers. POC in the Bohai Sea was mainly influenced by terrestrial and phytoplankton. POC in the Yellow Sea was influenced by various factors such as Changjiang Diluted Water, Yellow Sea warm current, Subei coastal current, biological and sediments. Organic debris were the main source of POC in coastal of Jiangsu and Qingdao near shore.
Based on the date of cruises that carried out in the Yellow Sea and the Bohai Sea during the summer of 2016. The concentration and special distribution of particulate organic carbon (POC) were analyzed and combined with the distribution of salinity, chlorophyll and POC/PON, POC/Chl a the source of POC were analyzed. Results showed that the average concentration of POC in the Bohai Sea, the North Yellow Sea and the South Yellow Sea were (500.2±226.5)μg/L, (358.2±101.5)μg/L, (321.0±158.1)μg/L,respectively. The concentration of POC in the Bohai Sea was higher than that in the Yellow Sea. The highest POC concentration was in the coastal zones and it tended to decrease toward the far shore on the whole. POC/PON was 8.89,POC/Chl a was 182.52 in the surface layer, POC/PON was 8.87, POC/Chl a was 179.56 in the middle layer, POC/PON was 9.41, POC/Chl a was 178.80 in the bottom layer. The high value of POC/PON and POC/Chl a had a certain relationship with the rotten of Enteromorpha prolifera. The result of correlation analysis showed salinity, total suspended matter and Chl a had a significant relationship with POC in the Bohai Sea which were the main factors influencing the distribution of POC in the Bohai Sea. In addition to the surface POC in the South Yellow Sea, there is no significant correlation between POC and salinity, total suspended matter, chlorophyll in other layers. POC in the Bohai Sea was mainly influenced by terrestrial and phytoplankton. POC in the Yellow Sea was influenced by various factors such as Changjiang Diluted Water, Yellow Sea warm current, Subei coastal current, biological and sediments. Organic debris were the main source of POC in coastal of Jiangsu and Qingdao near shore.
2018, 40(10): 209-219.
doi: 10.3969/j.issn.0253-4193.2018.10.020
Abstract:
In order to study the impact on concentration of dissolved uranium and sea flux in the lower reaches of the Yellow River during the water-sediment regulation scheme(WSRS), continuous synchronous observation and sampling, were conducted at Xiaolangdi Station and Lijin Station of the Yellow River in 2014. Results show that, in Xiaolangdi Station during the WSRS, the mean value of dissolved uranium concentrations were (4.28±0.33) μg/L and (4.19±0.29) μg/L in water regulation stage and sediment regulation stage, respectively. The mean value of dissolved uranium of Lijin Station were (4.55±0.22) μg/L(in sediment regulation stage) and (4.87±0.40) μg/L(in sediment regulation stage). The comparison shows that, the average dissolved uranium concentration of Lijin Station is higher than that of Xiaolangdi Station in both water regulation stage and sediment regulation stage, and the increased of dissolved uranium in sediment regulation stage is significantly higher than that in water regulation stage. Furthermore, the results indicate that the change of redox conditions and the particle size of the suspended matters are the main factors which have affected the chemical behavior of dissolved uranium in the lower reaches of the Yellow River. In 2014, the sea flux of dissolved uranium at Lijin Station was increased by 8.3×102 kg compared with that without WSRS. However, in 2015, under the condition of water regulation only, the dissolved uranium flux was decreased by 4.1×103 kg from Xiaolangdi Station to Lijin Station, indicating that different modes of WSRS had different effects on the sea flux of dissolved uranium. Due to the phenomenon that suspended particulate matter released dissolved uranium into water in the Yellow River estuary, so we estimated the sea flux of dissolved uranium released in the estuary according the increased content of suspended particulate matter and the desorption/dissolution coefficient during the WSRS, which were 1.57×104 kg, 0.739×104 kg, 0.690×104 kg and 8.25×102 kg in 2010, 2012, 2013, 2014, respectively, accounting for about 15%, 7.7%, 5.3% and 1.3% of the annual sea flux of dissolved uranium.
In order to study the impact on concentration of dissolved uranium and sea flux in the lower reaches of the Yellow River during the water-sediment regulation scheme(WSRS), continuous synchronous observation and sampling, were conducted at Xiaolangdi Station and Lijin Station of the Yellow River in 2014. Results show that, in Xiaolangdi Station during the WSRS, the mean value of dissolved uranium concentrations were (4.28±0.33) μg/L and (4.19±0.29) μg/L in water regulation stage and sediment regulation stage, respectively. The mean value of dissolved uranium of Lijin Station were (4.55±0.22) μg/L(in sediment regulation stage) and (4.87±0.40) μg/L(in sediment regulation stage). The comparison shows that, the average dissolved uranium concentration of Lijin Station is higher than that of Xiaolangdi Station in both water regulation stage and sediment regulation stage, and the increased of dissolved uranium in sediment regulation stage is significantly higher than that in water regulation stage. Furthermore, the results indicate that the change of redox conditions and the particle size of the suspended matters are the main factors which have affected the chemical behavior of dissolved uranium in the lower reaches of the Yellow River. In 2014, the sea flux of dissolved uranium at Lijin Station was increased by 8.3×102 kg compared with that without WSRS. However, in 2015, under the condition of water regulation only, the dissolved uranium flux was decreased by 4.1×103 kg from Xiaolangdi Station to Lijin Station, indicating that different modes of WSRS had different effects on the sea flux of dissolved uranium. Due to the phenomenon that suspended particulate matter released dissolved uranium into water in the Yellow River estuary, so we estimated the sea flux of dissolved uranium released in the estuary according the increased content of suspended particulate matter and the desorption/dissolution coefficient during the WSRS, which were 1.57×104 kg, 0.739×104 kg, 0.690×104 kg and 8.25×102 kg in 2010, 2012, 2013, 2014, respectively, accounting for about 15%, 7.7%, 5.3% and 1.3% of the annual sea flux of dissolved uranium.
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