A technology for obtaining microlayered composite materials of Cu-Zr-Y-Mo, Cu-Zr-Y-Cr, Cu-Zr-Y-W and Cu-Zr-Y-C systems by means of high-speed electron-beam evaporation-condensation, structure, electrical, and mechanic...A technology for obtaining microlayered composite materials of Cu-Zr-Y-Mo, Cu-Zr-Y-Cr, Cu-Zr-Y-W and Cu-Zr-Y-C systems by means of high-speed electron-beam evaporation-condensation, structure, electrical, and mechanical properties at ambient and elevated temperatures is developed.展开更多
The Fe, Zn, Mn and Pb concentrations in the seawater dissolved phase were investigated in the sea-surface microlayer （SML）, subsurface water （SSW） and bottom water （BW） samples collected at of three mariculture ...The Fe, Zn, Mn and Pb concentrations in the seawater dissolved phase were investigated in the sea-surface microlayer （SML）, subsurface water （SSW） and bottom water （BW） samples collected at of three mariculture areas of the Nanao Island ocean zone. The results showed that the SML and the BW were important compartments for these heavy metals in the mariculture areas and the concentrations varied from 23.0 μg/L to 268.0 μg/L（Fe）, 11.0 μg/L to 82.2 μg/L（Zn）, 1.5 μg/L to 11.0 μg/L（Mn） and 6.0 μg/L to 40.5 μg/L（Pb） in SSW, while a clear enrichment is observed in the SML, where these ranged from 27.5 μg/L to 286.5 μg/L（Fe）, 13.5/lg/L to 89.0μg/L（Zn）, 3.0μg/L to 12.0 μg/L（Mn） and 7.0 μg/L to 46.0μg/L（Pb）. The enrichment factors were in the range of 1.07 - 1.39 which showed a slight enrichment. The average enrichment factors of Fe, Zn, Pb and Mn were 1.18, 1.13, 1.12 and 1.30, respectively. The average enrichment factors in shellfish, fish and gracilaria lemaneaformis farming areas were 1.26, 1.19 and 1.11, respectively, which showed that the surface activity was highest in the shellfish farming area. Furthermore, the heavy metals concentrations were lowest in the gracUaria lemaneaformis farming area. The results of single factor contamination index showed that the investigated areas were slightly contaminated with Zn, while the partial farming areas were seriously contaminated with Pd during a certain period of time.展开更多
Both vertical and horizontal profiles of total dissolved selenium,dissolved organic and inorganic selenium,including Se(IV)and Se(VI),as well as particulate selenium in seawater were obtained on a basis of newly devel...Both vertical and horizontal profiles of total dissolved selenium,dissolved organic and inorganic selenium,including Se(IV)and Se(VI),as well as particulate selenium in seawater were obtained on a basis of newly developed separation technique form Antarctic Ocean,where the prodiction of deep waters occurs.The results exhibited that the concentrations of Se(IV) and Se(VI) were elevated and the total concentration in the surface of the high latitude waters (1. 31 nmol/L) was above those at lower latitudes (1.09 nmol/L) and also that previously reported from the Southern Ocean(1.18 nmol/L,Suzuki,1987).Preliminary investigation using specifically designed microlayer-sampler,that was first employed to identify the main biogeochemical proeesses,revealed Antarctic Ocean being functioning as a potential source as selenium in sea-air exchange. The mean life time of the selenium,detected as Se(IV) in deep water, was also estimated rather shorter than the residence time of the water mass, based on the samples collected from the cruise of China's Sixth Scientific Expedition.展开更多
The distributions of DMS and its precursor dimethylsulfoniopropionate, in both dissolved （DMSPd） and particulate fractions （DMSPp） were determined in the sea-surface microlayer and corresponding subsurface water o...The distributions of DMS and its precursor dimethylsulfoniopropionate, in both dissolved （DMSPd） and particulate fractions （DMSPp） were determined in the sea-surface microlayer and corresponding subsurface water of the Jiaozhou Bay, China and its adjacent area in May and August 2006. The concentrations of all these components showed a clear seasonal variation, with higher concen- trations occurring in summer. This can be mainly attributed to the higher phytoplankton biomass observed in summer. Simultaneously, the enrichment extents of DMSPd and DMSPp in the mi- crolayer also exhibited seasonal changes, with higher values in spring and lower ones in summer. Higher water temperature and stronger radiant intensity in summer can enhance their solubility and photochemical reaction in the microlayer water, reducing their enrichment factors （the ratio of concentration in the microlayer to that in the corresponding subsurface water）. A statistically significant relationship was found between the microlayer and subsurface water concentrations of DMS, DMSP and chlorophyll a, demonstrating that the biogenic materials in the microlayer come primarily from the underlying water. Moreover, our data show that the concentrations of DMSPp and DMS were significantly correlated with the levels of chlorophyll a, indicating that phytoplankton biomass might play an important role in controlling the distributions of biogenic sulfurs in the study area. The ratios of DMS/chlorophyll a and DMSPpchlorophyll a varied little from spring to summer, suggesting that there was no obvious change in the proportion of DMSP producers in the phytoplankton community. The mean sea-to-air flux of DMS from the study area was estimated to be 5.70 μmol/（m^2·d）, which highlights the effects of human impacts on DMS emission.展开更多
In situ and laboratory studies of sea -surface microlayer microlayer sampling methods using glass plate , rotating drum , screen and funnel samplers were conducted . For glass plate and rotating drum samplers, surface...In situ and laboratory studies of sea -surface microlayer microlayer sampling methods using glass plate , rotating drum , screen and funnel samplers were conducted . For glass plate and rotating drum samplers, surface microlayer samples of different thickness were collected by controlling their withdrawal rate and rotating rate. The relationships between pH, surface tension, the concentration of dissolved trace metals Cu and Pb, phophate , particulate mattersand sampling thickness were carefully investigated . It was shown that physicochemical and biological properties obviously at the sampling thickness of about 50 um, which is consistent with the mean thickness of the boundary film in the models of gas exchangee across the sea surface . It is proposed that the apparent sampling thickness of the surface microlayer should be less than 40 μm The factors affecting affecting the sampling thickness are discussed , and the feasibility and applicable conditions for different sampling methods are evaluated .展开更多
The water quality in the surface microlayer （SML） and subsurface water （SSW） in the Guangzhou segment of Pearl River, a eutrophic urban river section in China, were ana- lyzed. The spatial and temporal dynamics of...The water quality in the surface microlayer （SML） and subsurface water （SSW） in the Guangzhou segment of Pearl River, a eutrophic urban river section in China, were ana- lyzed. The spatial and temporal dynamics of nutrient concentrations, heavy metals and bac- teria were examined from two sampling sites in monthly samples throughout 2010. The mean concentrations of total nitrogen, ammonia, nitrate and nitrite were higher than 7.0 mg/L, 3.1 mg/L, 1.1 mg/L and 0.3 mg/L, while total phosphorus and orthophosphate were 0.5 mg/L and 0.1 mg/L, respectively. These results indicated that the water quality was rich in minerals and eutrophic. The mean concentrations of Mn and Fe were higher than 0.013 mg/L; and Ni, Cr and Pb were higher than 0.001 mg/L. The mean concentrations were in the order of Mn 〉Fe 〉 Ni 〉 Pb 〉 Cr. The concentrations of heavy metals in the Guangzhou segment were lower than the limit of the surface water quality standards in China and the World Health Organization （WHO）, but higher than the median values in the world＇s freshwater. The density of bacteria ranged from 3.30×10^5 to 5.23×10^6 cells/mL, and the amount of cultivable heterotrophic bac-teria ranged from 1.30×10^3 to 1.89×10^6 cfu/mL. Fecal coliform levels were beyond the V class of China water quality standard. The SML was enriched in nutrients, heavy metals and bac- teria, with the maximum enrichment factor of 3.84 for nutrients, 8.00 for heavy metals, and 3.04 for bacteria, suggesting that the water quality of the SML of the Guangzhou segment of the Pearl River was more serious than in the SSW.展开更多
Three fractions of alkaline phosphatase activity(APA),including phytoplankton APA(phyto-APA),bacterial APA(bact-APA),and free-APA,were examined in the sea surface microlayer(SML)and the subsurface water(SSW)from Daya ...Three fractions of alkaline phosphatase activity(APA),including phytoplankton APA(phyto-APA),bacterial APA(bact-APA),and free-APA,were examined in the sea surface microlayer(SML)and the subsurface water(SSW)from Daya Bay,Guishan Island,and Guanghai Bay of southern China.Relationships between APA and environmental parameters were analyzed.The growth of phytoplankton was significantly limited by dissolved inorganic phosphorus(DIP)in the three sea areas,especially in Daya Bay.TotalAPA ranged between 1.41 and 35.26 nmol/L/hr,and the highest value was found in Daya Bay.The increased APA in Daya Bay was the result of the increase of phytoplankton biomass and the response of phytoplankton to P limitation.Phyto-APA was the main contributor in Daya Bay,while phyto-and free-APA co-dominated in Guishan Island and Guanghai Bay.Bact-,phyto-,and total-APA showed a significant inverse power function relationship with DIP,and 0.2μmol/L was the threshold for DIP on particulates and totalAPA.Pearson correlation analysis suggested that DIP limitation together with high N levels enhanced APA.High water temperature and freshwater input accelerated APA as well.Principal component analysis clearly separated samples from the three sea areas,as well as from the SML and the SSW,which indicated the differences in environmental parameters and APA levels.Our results highlight the influence of phosphorus limitation and environmental parameters on APA.展开更多
Abstract The microlayer or nanolayer coextrusion of hundreds or thousands of alternating low density polyethylene （LDPE）/polystyrene （PS） microlayers or nanolayers were used to study the orientation of LDPE crysta...Abstract The microlayer or nanolayer coextrusion of hundreds or thousands of alternating low density polyethylene （LDPE）/polystyrene （PS） microlayers or nanolayers were used to study the orientation of LDPE crystals in the confined quasi-two-dimensional or two-dimensional space. The clear and continuous layer structures from microscale to nanoscale can be found in SEM images. The morphology evolution of LDPE crystals in the confined microlayer or nanolayer can he varied from 3D spherulites, 2D spherulites, stacked edge-on lamellar, to single edge-on lamellar. Due to the orientation of the LDPE crystals, the tensile strength of the films increases obviously when the layer thickness reduces to nanoscale. The 2D small angle X-ray scattering （SAXS） patterns can reflect the average degree of orientation of LDPE in the confined layers. The stacking of LDPE lamellae is suppressed in interlamination and oppositely in parallel to the extrusion direction. The specific orientation function f can be calculated from the patterns. The infrared dichroism further confirms the mutation of the orientation of LDPE crystals from microscale to nanoscale in the confined space.展开更多
Two cruises for multi discipline investigation were conducted in October and November, 1998 in Daya Bay to collect: (1) samples from five levels including sea surface microlayer (SML), subsurface (SSL), surface, body ...Two cruises for multi discipline investigation were conducted in October and November, 1998 in Daya Bay to collect: (1) samples from five levels including sea surface microlayer (SML), subsurface (SSL), surface, body (mid column) and bottom water; and (2) observational data on chlorophyll a and nutrients, and important factors such as turbidity, BOD, COD, TN, TP and phytoplankton. Results showed that there was no enrichment of chlorophyll a in the SML, but quite notable enrichment of some organic matter and nutrients. Compared with the findings in earlier researches, PO 4 P and SiO 3 Si have decreased, and the N/P ratio has increased obviously to even more than 100 in the SML. It is concluded preliminarily that PO 4 P and SiO 3 Si mainly determine phytoplankton growth in Daya Bay at present.展开更多
The enrichment of nutrients (Noa-, Noa-, PO43-), suspended particles, organic matter (POC, PON,DOC) , and trace metals (Cu, Ni, Cd) was determined in the sea surface microlayer of Xiamen Bay and Jiulong Estuary. The m...The enrichment of nutrients (Noa-, Noa-, PO43-), suspended particles, organic matter (POC, PON,DOC) , and trace metals (Cu, Ni, Cd) was determined in the sea surface microlayer of Xiamen Bay and Jiulong Estuary. The mean enrichment factors ([Xi]microlayer/[Xi ]15cm in depth) mostly ranged between 1 . 0 and 2. 0. The dissolved forms were the major forms of the components measured, the enrichment of dissolved organic matter and suspended particles could lead to the changes in the total amount and speciation of nutrients and trace metals. No correlation was observed between sample concentrations, speciation, enrichment factors and sample locations. However, some evidence shows that these parameters are correlated with sea state, indicating the complexity and dynamic nature of the sea surface microlayer.展开更多
Surface water can be divided into three layers from top downward： surface microlayer （SML, thickness≤50 μm）, subsurface layer （SSL, ≈25 cm） and surface layer （SL, l-5m）, among which the SML plays an importan...Surface water can be divided into three layers from top downward： surface microlayer （SML, thickness≤50 μm）, subsurface layer （SSL, ≈25 cm） and surface layer （SL, l-5m）, among which the SML plays an important role on sea-air interaction because of its unique physical-chemical property. Carbon dioxide system including DIC （dissolved inorganic carbon）, Alk （alkalinity）, pH and pCO： （partial pressure of CO2） in multilayered waters of the Yellow Sea was studied for the first time in March and May 2005. The results show that： DIC and Alk are obviously enriched in SML. The contents ofDIC, Alk and pCO2 become lower in turn from SML, SSL to SL, higher in March and lower in May, whereas for pH it was opposite. The relationship between DIC and Alk is clearly positive, but negative between pH and pCO2. Meanwhile, pCO2 and temperature/salinity is also in positive relation, pCO2 decreases with latitude increase. DIC and Alk show a similar variation trend with the maximum at 02：00-03：00, but pH and pCO2 show an opposite pattern. In addition, the distribution patterns are similar to each other in the three layers. The Yellow Sea is shown to be a sink of atmospheric CO2 in spring by two methods： （1） comparing pCO2 in seawater and atmosphere; （2） turning direction of ＂pH-depth＂ curve. Calculation on the base of pCO2 data in SML in four models shows that carbon flux in spring in the area was about -6.96×10^6 t C.展开更多
This study on the temporal and spatial variability of the viscosity and some chemical parameters in the sea surface microlayer (SML), the relationship between the viscosity and chemical parameters, and the influence o...This study on the temporal and spatial variability of the viscosity and some chemical parameters in the sea surface microlayer (SML), the relationship between the viscosity and chemical parameters, and the influence of the viscosity on the mass transfer coefficient ( K ) in the flux of materials through the air sea interface revealed that: The values of viscosity and some chemical parameters in the SML are higher than those in the sub surface layer (SSL), and at daytime are higher than those at night. The viscosity has positive corelation with chemical oxygen demand (COD), dissolved organic carbon (DOC) and salinity. The "SML effect" on K need not be considered because the SML effect on materials concentration is so small.展开更多
The sea surface microlayer(SML)is the thin boundary layer between the ocean and the atmosphere.Phytoplankton community in the SML is known as phytoneuston and has a different community structure and biomass from the p...The sea surface microlayer(SML)is the thin boundary layer between the ocean and the atmosphere.Phytoplankton community in the SML is known as phytoneuston and has a different community structure and biomass from the phytoplankton of the underlying bulk water.In this study,water samples were collected from the SML of Daya Bay in southern China in September,October,and December of 2013.Algal growth potential(AGP)tests were conducted by adding different forms of nitrogen(N),phosphorus(P)and silicate(Si).Phytoneuston grew well with both inorganic and organic nutrients,and showed comparable community structure after nutrient addition.A total of 16 pigments were analyzed in the SML samples collected from Daya Bay in this study.Phytopigments were dominated by the cyanobacteria-diagnostic pigment(zeaxanthin,Zea)in September and October,and by diatom-diagnostic pigment(fucoxanthin,Fuco)in December.The concentrations and proportions of Fuco increased greatly after the nutrient addition,and the concentrations and proportions of Zea decreased accordingly.Additionally,the diatom pigment index(DiatDP)increased after nutrient addition,and the prokaryotic pigment index(ProkDP)conversely decreased.The results suggested that massive occurrences of Zea and cyanobacteria are important characteristics of phytoneuston structure in Daya Bay especially in warm seasons,and nutrient addition especially Si addition promoted the growth of diatoms.展开更多
The authors’ surveys in May-June 1999 (two cruises) at six sampling stations near nuclear power plants (NPP) and marine fish culture zones in Daya Bay, Guangdong, revealed species composition, densities and body-size...The authors’ surveys in May-June 1999 (two cruises) at six sampling stations near nuclear power plants (NPP) and marine fish culture zones in Daya Bay, Guangdong, revealed species composition, densities and body-size of the sea surface microlayer (SM) zooplankton (>35 μm). Results showed that protozoans and copepod nauplii were the predominant components, accounting for 65.40% to 95.56% of total zooplankton in abundance. The size-frequency distributions showed that the frequency of micro-zooplankton (0.02-0.2 mm) reached 0.8235. The SM zooplankton community structure revealed in the present study was quite different from that revealed by investigations in the 1980s in Daya Bay. Difference of sampling method has important influence on the obtained zooplankton community structure. SM zooplankton consisted of micro- and mesozooplankton (0.2-2.0 mm), with micro-zooplankton being predominant. Some possible cause-effect relations between the zooplankton community structure and mariculture, nuclear power plants cooling systems and sampling method are discussed.展开更多
Characteristics of interaction between di-2-ethylhexyl phthalate(DEHP) and particulate in a eutrophic lake were studied in this paper. DEHP concentrations ranged from 89.9 to 247 μg/L with an average value of 146 μg...Characteristics of interaction between di-2-ethylhexyl phthalate(DEHP) and particulate in a eutrophic lake were studied in this paper. DEHP concentrations ranged from 89.9 to 247 μg/L with an average value of 146 μg/L in subsurface water (SSW) samples, and from 82.0 to 390 μg/L with an average value of 211 μg/L in water surface microlayer (SM) samples. The results indicate that there was only a weak correlation between the DEHP concentrations and suspended particulate material(SPM) concentrations in both SSW and SM, while the significant correlation between DEHP concentrations and chlorophyll a concentrations was found, which suggestes that DEHP was principally bound to phytoplankton in the eutrophic lake. Correlation between DEHP concentrations and total phosphor (TP) concentrations was also found in this investigation.Enrichment factors (EF) of DEHP in SM were in the range of 0.85 to 2.12 with an average value of 1.35. DEHP EFs were significantly related to the enrichment of chlorophyll a in SM. The results suggest that the enrichment of DEHP in SM of this eutrophic lake was mainly due to DEHP accumulation in phytoplankton and was controlled by distribution of phytoplankton between SM and SSW.展开更多
Glass-plate sampling during 1988-1999 in Daya Bay and suitable corresponding analytical methods were used for the measurement of dissolved trace metals, dissolved organic carbon, biological oxygen demand, chemical oxy...Glass-plate sampling during 1988-1999 in Daya Bay and suitable corresponding analytical methods were used for the measurement of dissolved trace metals, dissolved organic carbon, biological oxygen demand, chemical oxygen demand, salinity of the sea surface microlayer and subsurface water. Apparent enrichment mechanism and diurnal variation have been revealed for dissolved trace metals in the microlayer in Daya Bay. The more dissolved organic matter was enriched in the sea surface microlayer, the more dissolved trace metals were enriched in the layer. The organic matter played an important role in the enrichment process. The diurnal variations of dissolved trace metals showed that their concentration was apparently inversely related to the tide activity that the concentration was low during rising tide, but high during falling tide. The behavior of dissolved trace metals expressed by the diurnal variation was clearly opposite to that of salinity.展开更多
The preparation technology of microlayer composite material by the electron beam physical vapor deposition (EBPVD) technique was briefly introduced. Taking the advantage of the large-scale commercial softvare of finit...The preparation technology of microlayer composite material by the electron beam physical vapor deposition (EBPVD) technique was briefly introduced. Taking the advantage of the large-scale commercial softvare of finite element analysis, areasonable physical model was built up during the deposition processing and the distribution of residual stress was analyzedbetween substrate and deposition layer or among deposition layers. The results show that: with the increasing substrate preheating temperature, the interlaminar shear stress increases but the axial residual stress decreases. The probability of curlingup after de-bonding tends to enhance as the thickness of deposition film increases.展开更多
Enrichment of volatile organic compounds(VOC) and semi-volatility organic compounds(SVOC) in surface microlayer(SM) of three drinking water sources were studied. The enrichment factor( EF s) were 0.67 to 13.37 and 0.1...Enrichment of volatile organic compounds(VOC) and semi-volatility organic compounds(SVOC) in surface microlayer(SM) of three drinking water sources were studied. The enrichment factor( EF s) were 0.67 to 13.37 and 0.16 to 136, respectively. The results showed some VOC and most SVOC could enrich in SM. Some EF s of SVOC was quite high. Suspension and temperature could affect EF s of SVOC, slim wind and water movement do not destroy enrichment of organic in SM.展开更多
Copper complexing ligands concentration (C C) and conditional stability constant of the sea surface microlayer (SML) and subsurface layer (SSL) samples, collected from Daya Bay of Guangdong Province and Jiaozhou Bay o...Copper complexing ligands concentration (C C) and conditional stability constant of the sea surface microlayer (SML) and subsurface layer (SSL) samples, collected from Daya Bay of Guangdong Province and Jiaozhou Bay of Shandong Province, were determined by anodic stripping voltammetry (ASV) technique. C C of Daya Bay in the SML ranged from 6.19×10-7 to 3.52×10-7 mol/L. C C of Jiaozhou Bay in the SML ranged from 5.30×10-7 to 3.03×10-7 mol/L in August 1998 and from 3.46×10-7 to 1.36×10-7 mol/L in May 2000. The C C concentrations were higher in all surface microlayer samples, compared with corresponding subsurface samples. The average enrichment factors of copper complexation in the SML observed above were 1.58, 1.41 and 1.56, respectively. The enrichment of C C concentration in the microlayer demonstrated that organic ligands had certain buffer action on the toxicity of the enriched trace metals in the same layer. Conditional stability constants of the SML in Jiaozhou Bay were lower than those of the SSL; however, it showed just opposite for Daya Bay. BOD (biological oxygen demand) and COD (chemical oxygen demand) indicated the organic matter content, also showed enriched in the SML. C C had an obvious relationship with BOD or COD.展开更多
The authors propose a new "three-layer" conceptual model for the air-sea exchange of organic gases, which includes a dynamic surface microlayer with photochemical and biological processes. A parameterization...The authors propose a new "three-layer" conceptual model for the air-sea exchange of organic gases, which includes a dynamic surface microlayer with photochemical and biological processes. A parameterization of this three-layer model is presented, which was used to calculate the air-sea fluxes of acetone over the Pacific Ocean. The air-sea fluxes of acetone calculated by the three-layer model are in the same direction but possess half the magnitude of the fluxes calculated by the traditional two-layer model in the absence of photochemical and biological processes. However, photochemical and biological processes impacting acetone in the microlayer can greatly vary the calculated fluxes in the three-layer model, even reversing their direction under favorable conditions. Our model may help explain the discrepancies between measured and calculated acetone fluxes in previous studies. More measurements are needed to validate our conceptual model and provide constraints on the model parameters.展开更多
文摘A technology for obtaining microlayered composite materials of Cu-Zr-Y-Mo, Cu-Zr-Y-Cr, Cu-Zr-Y-W and Cu-Zr-Y-C systems by means of high-speed electron-beam evaporation-condensation, structure, electrical, and mechanical properties at ambient and elevated temperatures is developed.
基金supported by the National Natural Science Foundation of China (No.40673062)
文摘The Fe, Zn, Mn and Pb concentrations in the seawater dissolved phase were investigated in the sea-surface microlayer （SML）, subsurface water （SSW） and bottom water （BW） samples collected at of three mariculture areas of the Nanao Island ocean zone. The results showed that the SML and the BW were important compartments for these heavy metals in the mariculture areas and the concentrations varied from 23.0 μg/L to 268.0 μg/L（Fe）, 11.0 μg/L to 82.2 μg/L（Zn）, 1.5 μg/L to 11.0 μg/L（Mn） and 6.0 μg/L to 40.5 μg/L（Pb） in SSW, while a clear enrichment is observed in the SML, where these ranged from 27.5 μg/L to 286.5 μg/L（Fe）, 13.5/lg/L to 89.0μg/L（Zn）, 3.0μg/L to 12.0 μg/L（Mn） and 7.0 μg/L to 46.0μg/L（Pb）. The enrichment factors were in the range of 1.07 - 1.39 which showed a slight enrichment. The average enrichment factors of Fe, Zn, Pb and Mn were 1.18, 1.13, 1.12 and 1.30, respectively. The average enrichment factors in shellfish, fish and gracilaria lemaneaformis farming areas were 1.26, 1.19 and 1.11, respectively, which showed that the surface activity was highest in the shellfish farming area. Furthermore, the heavy metals concentrations were lowest in the gracUaria lemaneaformis farming area. The results of single factor contamination index showed that the investigated areas were slightly contaminated with Zn, while the partial farming areas were seriously contaminated with Pd during a certain period of time.
文摘Both vertical and horizontal profiles of total dissolved selenium,dissolved organic and inorganic selenium,including Se(IV)and Se(VI),as well as particulate selenium in seawater were obtained on a basis of newly developed separation technique form Antarctic Ocean,where the prodiction of deep waters occurs.The results exhibited that the concentrations of Se(IV) and Se(VI) were elevated and the total concentration in the surface of the high latitude waters (1. 31 nmol/L) was above those at lower latitudes (1.09 nmol/L) and also that previously reported from the Southern Ocean(1.18 nmol/L,Suzuki,1987).Preliminary investigation using specifically designed microlayer-sampler,that was first employed to identify the main biogeochemical proeesses,revealed Antarctic Ocean being functioning as a potential source as selenium in sea-air exchange. The mean life time of the selenium,detected as Se(IV) in deep water, was also estimated rather shorter than the residence time of the water mass, based on the samples collected from the cruise of China's Sixth Scientific Expedition.
基金The National Natural Science Foundation of China under contract Nos 40476034, 40525017 and 40490265 the Science and Technology Key Project of Shandong Province, China under contract No 2006GG2205024the Taishan Mountain Scholar Construction Engineering Special Fund of Shandong Province, China
文摘The distributions of DMS and its precursor dimethylsulfoniopropionate, in both dissolved （DMSPd） and particulate fractions （DMSPp） were determined in the sea-surface microlayer and corresponding subsurface water of the Jiaozhou Bay, China and its adjacent area in May and August 2006. The concentrations of all these components showed a clear seasonal variation, with higher concen- trations occurring in summer. This can be mainly attributed to the higher phytoplankton biomass observed in summer. Simultaneously, the enrichment extents of DMSPd and DMSPp in the mi- crolayer also exhibited seasonal changes, with higher values in spring and lower ones in summer. Higher water temperature and stronger radiant intensity in summer can enhance their solubility and photochemical reaction in the microlayer water, reducing their enrichment factors （the ratio of concentration in the microlayer to that in the corresponding subsurface water）. A statistically significant relationship was found between the microlayer and subsurface water concentrations of DMS, DMSP and chlorophyll a, demonstrating that the biogenic materials in the microlayer come primarily from the underlying water. Moreover, our data show that the concentrations of DMSPp and DMS were significantly correlated with the levels of chlorophyll a, indicating that phytoplankton biomass might play an important role in controlling the distributions of biogenic sulfurs in the study area. The ratios of DMS/chlorophyll a and DMSPpchlorophyll a varied little from spring to summer, suggesting that there was no obvious change in the proportion of DMSP producers in the phytoplankton community. The mean sea-to-air flux of DMS from the study area was estimated to be 5.70 μmol/（m^2·d）, which highlights the effects of human impacts on DMS emission.
文摘In situ and laboratory studies of sea -surface microlayer microlayer sampling methods using glass plate , rotating drum , screen and funnel samplers were conducted . For glass plate and rotating drum samplers, surface microlayer samples of different thickness were collected by controlling their withdrawal rate and rotating rate. The relationships between pH, surface tension, the concentration of dissolved trace metals Cu and Pb, phophate , particulate mattersand sampling thickness were carefully investigated . It was shown that physicochemical and biological properties obviously at the sampling thickness of about 50 um, which is consistent with the mean thickness of the boundary film in the models of gas exchangee across the sea surface . It is proposed that the apparent sampling thickness of the surface microlayer should be less than 40 μm The factors affecting affecting the sampling thickness are discussed , and the feasibility and applicable conditions for different sampling methods are evaluated .
基金Foundation： National Natural Science Foundation of China, No.41173079 The Project of Department of Science and Technology, China, No.2012BAC07B05, No.2012BAD18B01 Jinan University Project, No.21612324
文摘The water quality in the surface microlayer （SML） and subsurface water （SSW） in the Guangzhou segment of Pearl River, a eutrophic urban river section in China, were ana- lyzed. The spatial and temporal dynamics of nutrient concentrations, heavy metals and bac- teria were examined from two sampling sites in monthly samples throughout 2010. The mean concentrations of total nitrogen, ammonia, nitrate and nitrite were higher than 7.0 mg/L, 3.1 mg/L, 1.1 mg/L and 0.3 mg/L, while total phosphorus and orthophosphate were 0.5 mg/L and 0.1 mg/L, respectively. These results indicated that the water quality was rich in minerals and eutrophic. The mean concentrations of Mn and Fe were higher than 0.013 mg/L; and Ni, Cr and Pb were higher than 0.001 mg/L. The mean concentrations were in the order of Mn 〉Fe 〉 Ni 〉 Pb 〉 Cr. The concentrations of heavy metals in the Guangzhou segment were lower than the limit of the surface water quality standards in China and the World Health Organization （WHO）, but higher than the median values in the world＇s freshwater. The density of bacteria ranged from 3.30×10^5 to 5.23×10^6 cells/mL, and the amount of cultivable heterotrophic bac-teria ranged from 1.30×10^3 to 1.89×10^6 cfu/mL. Fecal coliform levels were beyond the V class of China water quality standard. The SML was enriched in nutrients, heavy metals and bac- teria, with the maximum enrichment factor of 3.84 for nutrients, 8.00 for heavy metals, and 3.04 for bacteria, suggesting that the water quality of the SML of the Guangzhou segment of the Pearl River was more serious than in the SSW.
基金supported by the Science & Technology Basic Resources Investigation Program of China (No. 2018FY100200)
文摘Three fractions of alkaline phosphatase activity(APA),including phytoplankton APA(phyto-APA),bacterial APA(bact-APA),and free-APA,were examined in the sea surface microlayer(SML)and the subsurface water(SSW)from Daya Bay,Guishan Island,and Guanghai Bay of southern China.Relationships between APA and environmental parameters were analyzed.The growth of phytoplankton was significantly limited by dissolved inorganic phosphorus(DIP)in the three sea areas,especially in Daya Bay.TotalAPA ranged between 1.41 and 35.26 nmol/L/hr,and the highest value was found in Daya Bay.The increased APA in Daya Bay was the result of the increase of phytoplankton biomass and the response of phytoplankton to P limitation.Phyto-APA was the main contributor in Daya Bay,while phyto-and free-APA co-dominated in Guishan Island and Guanghai Bay.Bact-,phyto-,and total-APA showed a significant inverse power function relationship with DIP,and 0.2μmol/L was the threshold for DIP on particulates and totalAPA.Pearson correlation analysis suggested that DIP limitation together with high N levels enhanced APA.High water temperature and freshwater input accelerated APA as well.Principal component analysis clearly separated samples from the three sea areas,as well as from the SML and the SSW,which indicated the differences in environmental parameters and APA levels.Our results highlight the influence of phosphorus limitation and environmental parameters on APA.
基金financially supported by Major Program for Fundamental Research of Shanghai Science & Technology Commission(No.14JC1492700)the Fundamental Research Funds for the Central Universities(No.0500219216)
文摘Abstract The microlayer or nanolayer coextrusion of hundreds or thousands of alternating low density polyethylene （LDPE）/polystyrene （PS） microlayers or nanolayers were used to study the orientation of LDPE crystals in the confined quasi-two-dimensional or two-dimensional space. The clear and continuous layer structures from microscale to nanoscale can be found in SEM images. The morphology evolution of LDPE crystals in the confined microlayer or nanolayer can he varied from 3D spherulites, 2D spherulites, stacked edge-on lamellar, to single edge-on lamellar. Due to the orientation of the LDPE crystals, the tensile strength of the films increases obviously when the layer thickness reduces to nanoscale. The 2D small angle X-ray scattering （SAXS） patterns can reflect the average degree of orientation of LDPE in the confined layers. The stacking of LDPE lamellae is suppressed in interlamination and oppositely in parallel to the extrusion direction. The specific orientation function f can be calculated from the patterns. The infrared dichroism further confirms the mutation of the orientation of LDPE crystals from microscale to nanoscale in the confined space.
文摘Two cruises for multi discipline investigation were conducted in October and November, 1998 in Daya Bay to collect: (1) samples from five levels including sea surface microlayer (SML), subsurface (SSL), surface, body (mid column) and bottom water; and (2) observational data on chlorophyll a and nutrients, and important factors such as turbidity, BOD, COD, TN, TP and phytoplankton. Results showed that there was no enrichment of chlorophyll a in the SML, but quite notable enrichment of some organic matter and nutrients. Compared with the findings in earlier researches, PO 4 P and SiO 3 Si have decreased, and the N/P ratio has increased obviously to even more than 100 in the SML. It is concluded preliminarily that PO 4 P and SiO 3 Si mainly determine phytoplankton growth in Daya Bay at present.
文摘The enrichment of nutrients (Noa-, Noa-, PO43-), suspended particles, organic matter (POC, PON,DOC) , and trace metals (Cu, Ni, Cd) was determined in the sea surface microlayer of Xiamen Bay and Jiulong Estuary. The mean enrichment factors ([Xi]microlayer/[Xi ]15cm in depth) mostly ranged between 1 . 0 and 2. 0. The dissolved forms were the major forms of the components measured, the enrichment of dissolved organic matter and suspended particles could lead to the changes in the total amount and speciation of nutrients and trace metals. No correlation was observed between sample concentrations, speciation, enrichment factors and sample locations. However, some evidence shows that these parameters are correlated with sea state, indicating the complexity and dynamic nature of the sea surface microlayer.
基金Supported by the Major Project of the NSFC (No.40490263)the NSFC (No.40076020, 40376022)+1 种基金the National Basic Research Program of China (973 Program) (No.2001CB409700)the Doctoral Program for Higher Education (No.20030423007).
文摘Surface water can be divided into three layers from top downward： surface microlayer （SML, thickness≤50 μm）, subsurface layer （SSL, ≈25 cm） and surface layer （SL, l-5m）, among which the SML plays an important role on sea-air interaction because of its unique physical-chemical property. Carbon dioxide system including DIC （dissolved inorganic carbon）, Alk （alkalinity）, pH and pCO： （partial pressure of CO2） in multilayered waters of the Yellow Sea was studied for the first time in March and May 2005. The results show that： DIC and Alk are obviously enriched in SML. The contents ofDIC, Alk and pCO2 become lower in turn from SML, SSL to SL, higher in March and lower in May, whereas for pH it was opposite. The relationship between DIC and Alk is clearly positive, but negative between pH and pCO2. Meanwhile, pCO2 and temperature/salinity is also in positive relation, pCO2 decreases with latitude increase. DIC and Alk show a similar variation trend with the maximum at 02：00-03：00, but pH and pCO2 show an opposite pattern. In addition, the distribution patterns are similar to each other in the three layers. The Yellow Sea is shown to be a sink of atmospheric CO2 in spring by two methods： （1） comparing pCO2 in seawater and atmosphere; （2） turning direction of ＂pH-depth＂ curve. Calculation on the base of pCO2 data in SML in four models shows that carbon flux in spring in the area was about -6.96×10^6 t C.
文摘This study on the temporal and spatial variability of the viscosity and some chemical parameters in the sea surface microlayer (SML), the relationship between the viscosity and chemical parameters, and the influence of the viscosity on the mass transfer coefficient ( K ) in the flux of materials through the air sea interface revealed that: The values of viscosity and some chemical parameters in the SML are higher than those in the sub surface layer (SSL), and at daytime are higher than those at night. The viscosity has positive corelation with chemical oxygen demand (COD), dissolved organic carbon (DOC) and salinity. The "SML effect" on K need not be considered because the SML effect on materials concentration is so small.
基金the Science&Technology Basic Resources Investigation Program of China(No.2018FY100200).
文摘The sea surface microlayer(SML)is the thin boundary layer between the ocean and the atmosphere.Phytoplankton community in the SML is known as phytoneuston and has a different community structure and biomass from the phytoplankton of the underlying bulk water.In this study,water samples were collected from the SML of Daya Bay in southern China in September,October,and December of 2013.Algal growth potential(AGP)tests were conducted by adding different forms of nitrogen(N),phosphorus(P)and silicate(Si).Phytoneuston grew well with both inorganic and organic nutrients,and showed comparable community structure after nutrient addition.A total of 16 pigments were analyzed in the SML samples collected from Daya Bay in this study.Phytopigments were dominated by the cyanobacteria-diagnostic pigment(zeaxanthin,Zea)in September and October,and by diatom-diagnostic pigment(fucoxanthin,Fuco)in December.The concentrations and proportions of Fuco increased greatly after the nutrient addition,and the concentrations and proportions of Zea decreased accordingly.Additionally,the diatom pigment index(DiatDP)increased after nutrient addition,and the prokaryotic pigment index(ProkDP)conversely decreased.The results suggested that massive occurrences of Zea and cyanobacteria are important characteristics of phytoneuston structure in Daya Bay especially in warm seasons,and nutrient addition especially Si addition promoted the growth of diatoms.
文摘The authors’ surveys in May-June 1999 (two cruises) at six sampling stations near nuclear power plants (NPP) and marine fish culture zones in Daya Bay, Guangdong, revealed species composition, densities and body-size of the sea surface microlayer (SM) zooplankton (>35 μm). Results showed that protozoans and copepod nauplii were the predominant components, accounting for 65.40% to 95.56% of total zooplankton in abundance. The size-frequency distributions showed that the frequency of micro-zooplankton (0.02-0.2 mm) reached 0.8235. The SM zooplankton community structure revealed in the present study was quite different from that revealed by investigations in the 1980s in Daya Bay. Difference of sampling method has important influence on the obtained zooplankton community structure. SM zooplankton consisted of micro- and mesozooplankton (0.2-2.0 mm), with micro-zooplankton being predominant. Some possible cause-effect relations between the zooplankton community structure and mariculture, nuclear power plants cooling systems and sampling method are discussed.
文摘Characteristics of interaction between di-2-ethylhexyl phthalate(DEHP) and particulate in a eutrophic lake were studied in this paper. DEHP concentrations ranged from 89.9 to 247 μg/L with an average value of 146 μg/L in subsurface water (SSW) samples, and from 82.0 to 390 μg/L with an average value of 211 μg/L in water surface microlayer (SM) samples. The results indicate that there was only a weak correlation between the DEHP concentrations and suspended particulate material(SPM) concentrations in both SSW and SM, while the significant correlation between DEHP concentrations and chlorophyll a concentrations was found, which suggestes that DEHP was principally bound to phytoplankton in the eutrophic lake. Correlation between DEHP concentrations and total phosphor (TP) concentrations was also found in this investigation.Enrichment factors (EF) of DEHP in SM were in the range of 0.85 to 2.12 with an average value of 1.35. DEHP EFs were significantly related to the enrichment of chlorophyll a in SM. The results suggest that the enrichment of DEHP in SM of this eutrophic lake was mainly due to DEHP accumulation in phytoplankton and was controlled by distribution of phytoplankton between SM and SSW.
文摘Glass-plate sampling during 1988-1999 in Daya Bay and suitable corresponding analytical methods were used for the measurement of dissolved trace metals, dissolved organic carbon, biological oxygen demand, chemical oxygen demand, salinity of the sea surface microlayer and subsurface water. Apparent enrichment mechanism and diurnal variation have been revealed for dissolved trace metals in the microlayer in Daya Bay. The more dissolved organic matter was enriched in the sea surface microlayer, the more dissolved trace metals were enriched in the layer. The organic matter played an important role in the enrichment process. The diurnal variations of dissolved trace metals showed that their concentration was apparently inversely related to the tide activity that the concentration was low during rising tide, but high during falling tide. The behavior of dissolved trace metals expressed by the diurnal variation was clearly opposite to that of salinity.
基金This work was supported by the Natural Science Foundation of Hei Longjiang Province (E01-07) and China Postdoctoral Science Foundation that support this research (LB0047).
文摘The preparation technology of microlayer composite material by the electron beam physical vapor deposition (EBPVD) technique was briefly introduced. Taking the advantage of the large-scale commercial softvare of finite element analysis, areasonable physical model was built up during the deposition processing and the distribution of residual stress was analyzedbetween substrate and deposition layer or among deposition layers. The results show that: with the increasing substrate preheating temperature, the interlaminar shear stress increases but the axial residual stress decreases. The probability of curlingup after de-bonding tends to enhance as the thickness of deposition film increases.
文摘Enrichment of volatile organic compounds(VOC) and semi-volatility organic compounds(SVOC) in surface microlayer(SM) of three drinking water sources were studied. The enrichment factor( EF s) were 0.67 to 13.37 and 0.16 to 136, respectively. The results showed some VOC and most SVOC could enrich in SM. Some EF s of SVOC was quite high. Suspension and temperature could affect EF s of SVOC, slim wind and water movement do not destroy enrichment of organic in SM.
基金Supported by subproject of the China’s "Ninth Five Year Plan" Scientific Research Project No. 97-926-04-03 the Natural Science Foundation of China (No. 40076020, 40376022) the Doctoral Research Program of Higher Education (No. 98042304) and KZ95T-04-04-04 Fund.
文摘Copper complexing ligands concentration (C C) and conditional stability constant of the sea surface microlayer (SML) and subsurface layer (SSL) samples, collected from Daya Bay of Guangdong Province and Jiaozhou Bay of Shandong Province, were determined by anodic stripping voltammetry (ASV) technique. C C of Daya Bay in the SML ranged from 6.19×10-7 to 3.52×10-7 mol/L. C C of Jiaozhou Bay in the SML ranged from 5.30×10-7 to 3.03×10-7 mol/L in August 1998 and from 3.46×10-7 to 1.36×10-7 mol/L in May 2000. The C C concentrations were higher in all surface microlayer samples, compared with corresponding subsurface samples. The average enrichment factors of copper complexation in the SML observed above were 1.58, 1.41 and 1.56, respectively. The enrichment of C C concentration in the microlayer demonstrated that organic ligands had certain buffer action on the toxicity of the enriched trace metals in the same layer. Conditional stability constants of the SML in Jiaozhou Bay were lower than those of the SSL; however, it showed just opposite for Daya Bay. BOD (biological oxygen demand) and COD (chemical oxygen demand) indicated the organic matter content, also showed enriched in the SML. C C had an obvious relationship with BOD or COD.
基金funded by the National Natural Science Foundation of China (Grant No. 41222035)
文摘The authors propose a new "three-layer" conceptual model for the air-sea exchange of organic gases, which includes a dynamic surface microlayer with photochemical and biological processes. A parameterization of this three-layer model is presented, which was used to calculate the air-sea fluxes of acetone over the Pacific Ocean. The air-sea fluxes of acetone calculated by the three-layer model are in the same direction but possess half the magnitude of the fluxes calculated by the traditional two-layer model in the absence of photochemical and biological processes. However, photochemical and biological processes impacting acetone in the microlayer can greatly vary the calculated fluxes in the three-layer model, even reversing their direction under favorable conditions. Our model may help explain the discrepancies between measured and calculated acetone fluxes in previous studies. More measurements are needed to validate our conceptual model and provide constraints on the model parameters.
