Abundance and biomass of heterotrophic microbes were investigated usingepifluorescense microscopy in August 2004 along a transect in the Kongsfjorden, a glacial fjord inthe high arctic, located in the north-western pa...Abundance and biomass of heterotrophic microbes were investigated usingepifluorescense microscopy in August 2004 along a transect in the Kongsfjorden, a glacial fjord inthe high arctic, located in the north-western part of Svalbard. A bacterial abundance was low atouter fjord stations (on average 2.29 x 10~8 ind./dm^3) and was higher at inner fjord stations (onaverage 3.52 x 10~8 ind./dm^3).The biomass of bacteria ranged from 3.69 to 8.01 mg/m^3.The abundanceof bacteria was low at the surface of water(0 m), whereas the higher abundances often occurred atdepths of 30~50 m.The abundance of heterotrophic flagellates varied from 2.785 to 8.891 x 10~4 ind./dm^3. The assemblage was numerically dominated by less than 5 μm heterotrophic flagellates(78.67%~94.80%).The biomass of heterotrophic flagellates varied from 0.37 to 2.30 mg/m^3.The meanbiomass distribution for all stations was 4.91% for less than 5 μm heterotrophic flagellates,86.74% for 6~20 μm flagellates and 8.35% for greater than 20 μm sized flagellates.The low biomassof heterotrophic flagellates often occurred at the surface of water (0 m),while the maximum valueof biomass occurred at different depths. The biomass of total heterotrophic microbial communityranged from 4.20 to 10.03 mg/m^3.The mean biomass distribution for all stations was 82.58% forbacteria, 15.77% for flagellates and 1.66% for ciliates.展开更多
Kongsfjorden is a fjord in Spitsbergen(Svalbard archipelago)that lies adjacent to both Arctic and Atlantic water masses and is therefore a suitable site to understand the effects of climate change on ecosystems.To d...Kongsfjorden is a fjord in Spitsbergen(Svalbard archipelago)that lies adjacent to both Arctic and Atlantic water masses and is therefore a suitable site to understand the effects of climate change on ecosystems.To decipher the effect of the lateral advection of transformed Atlantic water (TAW)within the fjord,spatial variations of foraminiferal tests,their test size variations and stable isotopic composition(δ^(13)C andδ^(18)O)in the surface sediments were studied.Total organic carbon and textural analyses were also carried out.The dominant benthic foraminifera included Nonionellina labradorica,Elphidium excavatum,Cassidulina reniforme,Quinqueloculina stalkeri and Islandiella islandica.Nonionellina labradorica was the predominant species in the outer fjord,whereas Elphidium excavatum and Cassidulina reniforme were dominant in the inner fjord.Total organic carbon and the test size of Nonionellina labradorica within the fjord were highly correlated(r=0.97)and both showed a decreasing trend towards the inner fjord.Based on the distribution and abundance of Nonionellina labradorica as well as temperature profiles,we suggest that there was little or no major change in the lateral advection of TAW within the fjord in the immediate past.展开更多
The 16S and 18S ribosomal ribonucleic acid genes of microbial organisms collected from the contrasting environments (temperature, salinity, silicate, phosphate and nitrate, p 〈0.05) of the inner and outer basins of...The 16S and 18S ribosomal ribonucleic acid genes of microbial organisms collected from the contrasting environments (temperature, salinity, silicate, phosphate and nitrate, p 〈0.05) of the inner and outer basins of Kongsfjorden (Spitsbergen, Arctic) were studied using polymerase chain reaction-denaturing gradient gel electrophoresis(DGGE) fingerprinting. Comparison of the microbial fingerprints and the physicochemical parameters revealed that molecular methodology exhibited a greater sensitivity. Sequences obtained from bacterial DGGE were affiliated with four main phylogenetic groups of bacteria:Proteobacteria(Alpha, Beta and Gamma), Bacteroidetes, Verrucomicrobia and Cyanobacteria. The relationships between the genotype distribution of these microbes and associated biotic/abiotic factors, revealed by canonical correspondence analysis, showed that Station 1 at 30 m (outer fjord) was grouped separately from the other sites. This difference could be a consequence of the thermocline and base of the euphotic layer at this depth where the Atlantic and Arctic-type waters overlapped.展开更多
The basic environmental variables and adaptability ofphytoplankton communities to low light and salinity were stud- ied using incubation experiments in Kongsfjorden, a high Arctic fjord of Spitsbergen, in late summer ...The basic environmental variables and adaptability ofphytoplankton communities to low light and salinity were stud- ied using incubation experiments in Kongsfjorden, a high Arctic fjord of Spitsbergen, in late summer 2006. Chlorophyll a concentrations were steady or decreased slightly in darkness after one day or one week incubation. Chlorophyll a concentrations showed an initial decline when exposed to natural light after one week incubation in darkness, and then increased significantly. In a salinity experiment, the maximal growth rate was observed at a dilution ratio of 10%, however, higher dilution ratios (≥0%) had an obvious negative effect on phytoplankton growth. We suggest that the phytoplankton communities in fjords in late summer are dark- ness adapted, and the inflow of glacial melt water is favorable for phytoplankton growth in the outer fiords where the influence of freshwater is limited.展开更多
Kongsfjorden is a typical fjord on the edge of the ice cap of the Arctic Svalbard-Barents Sea. Its inner bay is connected with a modern glacier front along the direction of the fjord axis with a significant gradient c...Kongsfjorden is a typical fjord on the edge of the ice cap of the Arctic Svalbard-Barents Sea. Its inner bay is connected with a modern glacier front along the direction of the fjord axis with a significant gradient change in the parameters of hydrology, sedimentation, and biology. In summer, ice and snow melt-water and floating ice collapse continuously and thus transport the weathering products on the surrounding land into the sea. Thus Kongsfjorden is regards as a natural laboratory for the study of unique sedimentation in polar fjords under modern glacial-sea water conditions. In this study, fifty-two surface sediments were collected in Kongsfjorden for clay mineral analysis to study the sediment source and sediment-transport process. Our results indicate that clay minerals in the surface sediments from Kongsfjorden are mainly composed of illite, chlorite, and kaolinite, and no smectite is found. Rocks from different periods exposed extensively in the surrounding areas of Kongsfjorden provide an important material basis for clay minerals in the Kongsfjorden. Kaolinite may be mainly derived from the fluvial deposits, weathered from reddish sandstones and conglomerates during the Carboniferous Period.Illite is mainly derived from Proterozoic low-grade and medium-grade metamorphic phyllite, mica schist, and gneiss. While chlorite is mainly from Proterozoic low-grade metamorphic phyllite and mica schist. In the direction from the fluvio-glacial estuary to the sea of the glacier front of Kongsfjorden, illite increase gradually,and the content of kaolinite declines gradually. However, the change pattern of chlorite is insignificant, which may be related to the provenance. Kongsfjorden detritus is mainly transported by the fluvio-glacial streams and icebergs into the sea and deposited in the inner bay. Coarse sediments are rapidly deposited in the glacier front,estuary, and near-shore areas. Clay fraction begins to deposit significantly by 200–400 m after flowing into the sea,which due to the crystal behavior of clay minerals, hydrodynamic condition and flocculation. Kaolinite and chlorite on the south of the bay near the Blomstrandhalv?ya Island is mainly affected by ice-rafted detritus and thus can reveal the trajectory of transportation by the floating ice while entering the sea.展开更多
Kongsfjorden is known for its characteristic multi-layer water mass formed by the convergence of freshwaters from nearby glaciers and rivers and saline water from the Atlantic and Arctic.The distribution of polycyclic...Kongsfjorden is known for its characteristic multi-layer water mass formed by the convergence of freshwaters from nearby glaciers and rivers and saline water from the Atlantic and Arctic.The distribution of polycyclic aromatic hydrocarbons(PAHs)in the water column of Kongsfjorden was investigated and their potential sources were analyzed.The total concentrations of 16 PAHs in the surface seawater and river water were in the range of 33.4-79.8 ng/L(mean 48.5 ng/L)and 2.3-201.4 ng/L(mean 126.1 ng/L),respectively.Horizontally,PAHs were mainly concentrated around river estuaries and the glacier front in the dissolved phase.Vertically,the PAHs in the particulate phase followed surface-enrichment and depth-depletion patterns in most stations,with the maximum concentration found at 50 m depth in the central area of Kongsfjorden.The compositions of PAHs in seawater and rivers were similar,with two-ring and tricyclic PAHs comprising the majority of the dissolved and particulate phases.PAHs found in Kongsfjorden waters appeared to be derived from multiple sources such as petroleum and coal combustion.PAHs in the bay mouth of Kongsfjorden were mainly introduced by the West Spitsbergen Current and the Arctic waters,while in the inner bay,atmospheric deposition and local sources were the major contributors.The distribution of PAHs was mainly attributed to the suspended particulate distribution.展开更多
Humic substances are ubiquitous natural materials found in sediments as a product of biochemical transformation reactions representing a significant proportion of organic carbon cycle on earth. This study involves the...Humic substances are ubiquitous natural materials found in sediments as a product of biochemical transformation reactions representing a significant proportion of organic carbon cycle on earth. This study involves the analysis of humic substances with special emphasis on humic acids(HAs) in sediments collected from the Kongsfjorden System of Arctic region in June, 2017. The characterization of the isolated HAs were done using various spectroscopic techniques viz. UV-visible, Fluorescence, FTIR and NMR. Isolated HAs were also undergone for elemental analysis along with other characterization. The UV spectral analysis results with a lower E4/E6 ratio suggesting the presence of HAs with high degree of aromaticity and condensation. Indications for the presence of hydroxyl, methyl, methylene, carbonyl, carboxyl, phenol, alcohol and amide groups were obtained from the FTIR spectrums of HAs. NMR spectral characteristics also confirm the presence of OH group as well as the presence of CH protons adjacent to C=X, were X can be any electronegative element. This also confirms the presence of carbonyl group which is also evident in the FTIR spectral studies. Presence of aliphatic regions slightly more dominated with long chain and/or alicyclic moieties rather than methyl groups was also inferred from the results of NMR.展开更多
The Kongsfjorden is highly sensitive region to climate variability,however,the study of gamma-ray radionuclides in related areas is relatively scarce.In this study,the grain size,total organic carbon(TOC),13 Corg isot...The Kongsfjorden is highly sensitive region to climate variability,however,the study of gamma-ray radionuclides in related areas is relatively scarce.In this study,the grain size,total organic carbon(TOC),13 Corg isotopes,and specific activities of seven gamma nuclides were analysed in surface sediments of the Kongsfjorden in the Arctic during the summer of 2017.The specific activities of 210 Pb_(ex),137 Cs,238 U,226 Ra,228 Ra,228 Th,and 40 K were 12–256 Bq/kg,0–3.8 Bq/kg,25–42 Bq/kg,24–38 Bq/kg,22–40 Bq/kg,22–40 Bq/kg,and 354–738 Bq/kg,respectively,with average values of(121±94)Bq/kg,(2.0±1.2)Bq/kg,(34±6)Bq/kg,(32±4)Bq/kg,(32±6)Bq/kg,(33±6)Bq/kg,and(611±119)Bq/kg.This study observed a significant positive correlation(r=0.845,p<0.05)between TOC and 210 Pb_(ex),highlighting the strong influence of organic matter on the distribution of 210 Pb_(ex).The boundary scavenging of210 Pb from the open sea contributed 27.5%–46.2%to the total 210 Pb_(ex) in the sediments of the outer Kongsfjorden.The grain size was an important factor affecting the activity distribution of several radionuclides(238 U,228 Ra,228 Th,226 Ra,and 40 K).The specific activity of 137 Cs indicated the transport of terrestrial materials from the exposed area of the Kongsfjorden.The sediments in the Kongsfjorden were derived from various material contributions of glacial meltwater debris,glacial rivers,bare soil,atmospheric deposition,and marine sources.This study explains the source of the Kongsfjorden sediment and the distribution characteristics of radionuclides,and illustrateas the main factors affecting the distribution of radionuclides,which provides a reference for the behavior of polar radionuclides in future research.展开更多
基金supported by the National Natural Science Foundation of China under contract Nos 40576002,40006010 and 30270112the Polar Research Institute of China Innovation Founda-tion of Polar Science for Young Scientists under con-tract No.JDQ200502+1 种基金the Basic Research Project of Ministry of Scienle and Technology of China under contract No.2003DEB5J057the Oceanic Science Foundation of State Oceanic Administration under contract No.2003122.
文摘Abundance and biomass of heterotrophic microbes were investigated usingepifluorescense microscopy in August 2004 along a transect in the Kongsfjorden, a glacial fjord inthe high arctic, located in the north-western part of Svalbard. A bacterial abundance was low atouter fjord stations (on average 2.29 x 10~8 ind./dm^3) and was higher at inner fjord stations (onaverage 3.52 x 10~8 ind./dm^3).The biomass of bacteria ranged from 3.69 to 8.01 mg/m^3.The abundanceof bacteria was low at the surface of water(0 m), whereas the higher abundances often occurred atdepths of 30~50 m.The abundance of heterotrophic flagellates varied from 2.785 to 8.891 x 10~4 ind./dm^3. The assemblage was numerically dominated by less than 5 μm heterotrophic flagellates(78.67%~94.80%).The biomass of heterotrophic flagellates varied from 0.37 to 2.30 mg/m^3.The meanbiomass distribution for all stations was 4.91% for less than 5 μm heterotrophic flagellates,86.74% for 6~20 μm flagellates and 8.35% for greater than 20 μm sized flagellates.The low biomassof heterotrophic flagellates often occurred at the surface of water (0 m),while the maximum valueof biomass occurred at different depths. The biomass of total heterotrophic microbial communityranged from 4.20 to 10.03 mg/m^3.The mean biomass distribution for all stations was 82.58% forbacteria, 15.77% for flagellates and 1.66% for ciliates.
文摘Kongsfjorden is a fjord in Spitsbergen(Svalbard archipelago)that lies adjacent to both Arctic and Atlantic water masses and is therefore a suitable site to understand the effects of climate change on ecosystems.To decipher the effect of the lateral advection of transformed Atlantic water (TAW)within the fjord,spatial variations of foraminiferal tests,their test size variations and stable isotopic composition(δ^(13)C andδ^(18)O)in the surface sediments were studied.Total organic carbon and textural analyses were also carried out.The dominant benthic foraminifera included Nonionellina labradorica,Elphidium excavatum,Cassidulina reniforme,Quinqueloculina stalkeri and Islandiella islandica.Nonionellina labradorica was the predominant species in the outer fjord,whereas Elphidium excavatum and Cassidulina reniforme were dominant in the inner fjord.Total organic carbon and the test size of Nonionellina labradorica within the fjord were highly correlated(r=0.97)and both showed a decreasing trend towards the inner fjord.Based on the distribution and abundance of Nonionellina labradorica as well as temperature profiles,we suggest that there was little or no major change in the lateral advection of TAW within the fjord in the immediate past.
基金supported by the National Natural Science Foundation of China (Grant Nos.41076130, 40576002)the International Cooperation Project of Science and Technology Commission of Shanghai Municipality (Grant no. 052307053)+1 种基金the Youth Marine Science Foundation of SOA (Grant no. 2010116)the Open Research Foundation of the SOA Laboratory of Marine Ecosystem and Biogeochemistry (Grant no. LMEB200902)
文摘The 16S and 18S ribosomal ribonucleic acid genes of microbial organisms collected from the contrasting environments (temperature, salinity, silicate, phosphate and nitrate, p 〈0.05) of the inner and outer basins of Kongsfjorden (Spitsbergen, Arctic) were studied using polymerase chain reaction-denaturing gradient gel electrophoresis(DGGE) fingerprinting. Comparison of the microbial fingerprints and the physicochemical parameters revealed that molecular methodology exhibited a greater sensitivity. Sequences obtained from bacterial DGGE were affiliated with four main phylogenetic groups of bacteria:Proteobacteria(Alpha, Beta and Gamma), Bacteroidetes, Verrucomicrobia and Cyanobacteria. The relationships between the genotype distribution of these microbes and associated biotic/abiotic factors, revealed by canonical correspondence analysis, showed that Station 1 at 30 m (outer fjord) was grouped separately from the other sites. This difference could be a consequence of the thermocline and base of the euphotic layer at this depth where the Atlantic and Arctic-type waters overlapped.
基金supported by the National Natural Science Foundation of China (Grant nos. 41076130, 40576002)the Youth Marine Science Foundation of SOA (Grant no. 2010116)
文摘The basic environmental variables and adaptability ofphytoplankton communities to low light and salinity were stud- ied using incubation experiments in Kongsfjorden, a high Arctic fjord of Spitsbergen, in late summer 2006. Chlorophyll a concentrations were steady or decreased slightly in darkness after one day or one week incubation. Chlorophyll a concentrations showed an initial decline when exposed to natural light after one week incubation in darkness, and then increased significantly. In a salinity experiment, the maximal growth rate was observed at a dilution ratio of 10%, however, higher dilution ratios (≥0%) had an obvious negative effect on phytoplankton growth. We suggest that the phytoplankton communities in fjords in late summer are dark- ness adapted, and the inflow of glacial melt water is favorable for phytoplankton growth in the outer fiords where the influence of freshwater is limited.
基金The National Natural Science Foundation of China under contract Nos 41606223 and U1606401the Basic Scientific Fund for National Public Research Institutes of China under contract No.2011G27+1 种基金the Polar Strategic Research Foundation of China under contract No.20140305the Taishan Scholar Program of Shandong Province
文摘Kongsfjorden is a typical fjord on the edge of the ice cap of the Arctic Svalbard-Barents Sea. Its inner bay is connected with a modern glacier front along the direction of the fjord axis with a significant gradient change in the parameters of hydrology, sedimentation, and biology. In summer, ice and snow melt-water and floating ice collapse continuously and thus transport the weathering products on the surrounding land into the sea. Thus Kongsfjorden is regards as a natural laboratory for the study of unique sedimentation in polar fjords under modern glacial-sea water conditions. In this study, fifty-two surface sediments were collected in Kongsfjorden for clay mineral analysis to study the sediment source and sediment-transport process. Our results indicate that clay minerals in the surface sediments from Kongsfjorden are mainly composed of illite, chlorite, and kaolinite, and no smectite is found. Rocks from different periods exposed extensively in the surrounding areas of Kongsfjorden provide an important material basis for clay minerals in the Kongsfjorden. Kaolinite may be mainly derived from the fluvial deposits, weathered from reddish sandstones and conglomerates during the Carboniferous Period.Illite is mainly derived from Proterozoic low-grade and medium-grade metamorphic phyllite, mica schist, and gneiss. While chlorite is mainly from Proterozoic low-grade metamorphic phyllite and mica schist. In the direction from the fluvio-glacial estuary to the sea of the glacier front of Kongsfjorden, illite increase gradually,and the content of kaolinite declines gradually. However, the change pattern of chlorite is insignificant, which may be related to the provenance. Kongsfjorden detritus is mainly transported by the fluvio-glacial streams and icebergs into the sea and deposited in the inner bay. Coarse sediments are rapidly deposited in the glacier front,estuary, and near-shore areas. Clay fraction begins to deposit significantly by 200–400 m after flowing into the sea,which due to the crystal behavior of clay minerals, hydrodynamic condition and flocculation. Kaolinite and chlorite on the south of the bay near the Blomstrandhalv?ya Island is mainly affected by ice-rafted detritus and thus can reveal the trajectory of transportation by the floating ice while entering the sea.
基金supported by the National Key R&D Program of China(2019YFD0901104)the National Natural Science Foun-dation of China(Nos.41976222,21377032)+1 种基金the Open Fund for the Key Laboratory of Ocean-Atmospheric Chemistry and Global Change,State Oceanic Administration(No.GCMAC1812)the Open Fund for the State Key Laboratory of Environmental Chemistry and Ecotoxicology(No.KF2018-05)。
文摘Kongsfjorden is known for its characteristic multi-layer water mass formed by the convergence of freshwaters from nearby glaciers and rivers and saline water from the Atlantic and Arctic.The distribution of polycyclic aromatic hydrocarbons(PAHs)in the water column of Kongsfjorden was investigated and their potential sources were analyzed.The total concentrations of 16 PAHs in the surface seawater and river water were in the range of 33.4-79.8 ng/L(mean 48.5 ng/L)and 2.3-201.4 ng/L(mean 126.1 ng/L),respectively.Horizontally,PAHs were mainly concentrated around river estuaries and the glacier front in the dissolved phase.Vertically,the PAHs in the particulate phase followed surface-enrichment and depth-depletion patterns in most stations,with the maximum concentration found at 50 m depth in the central area of Kongsfjorden.The compositions of PAHs in seawater and rivers were similar,with two-ring and tricyclic PAHs comprising the majority of the dissolved and particulate phases.PAHs found in Kongsfjorden waters appeared to be derived from multiple sources such as petroleum and coal combustion.PAHs in the bay mouth of Kongsfjorden were mainly introduced by the West Spitsbergen Current and the Arctic waters,while in the inner bay,atmospheric deposition and local sources were the major contributors.The distribution of PAHs was mainly attributed to the suspended particulate distribution.
文摘Humic substances are ubiquitous natural materials found in sediments as a product of biochemical transformation reactions representing a significant proportion of organic carbon cycle on earth. This study involves the analysis of humic substances with special emphasis on humic acids(HAs) in sediments collected from the Kongsfjorden System of Arctic region in June, 2017. The characterization of the isolated HAs were done using various spectroscopic techniques viz. UV-visible, Fluorescence, FTIR and NMR. Isolated HAs were also undergone for elemental analysis along with other characterization. The UV spectral analysis results with a lower E4/E6 ratio suggesting the presence of HAs with high degree of aromaticity and condensation. Indications for the presence of hydroxyl, methyl, methylene, carbonyl, carboxyl, phenol, alcohol and amide groups were obtained from the FTIR spectrums of HAs. NMR spectral characteristics also confirm the presence of OH group as well as the presence of CH protons adjacent to C=X, were X can be any electronegative element. This also confirms the presence of carbonyl group which is also evident in the FTIR spectral studies. Presence of aliphatic regions slightly more dominated with long chain and/or alicyclic moieties rather than methyl groups was also inferred from the results of NMR.
基金The National Natural Science Foundation of China under contract Nos 41706089 and 42107251。
文摘The Kongsfjorden is highly sensitive region to climate variability,however,the study of gamma-ray radionuclides in related areas is relatively scarce.In this study,the grain size,total organic carbon(TOC),13 Corg isotopes,and specific activities of seven gamma nuclides were analysed in surface sediments of the Kongsfjorden in the Arctic during the summer of 2017.The specific activities of 210 Pb_(ex),137 Cs,238 U,226 Ra,228 Ra,228 Th,and 40 K were 12–256 Bq/kg,0–3.8 Bq/kg,25–42 Bq/kg,24–38 Bq/kg,22–40 Bq/kg,22–40 Bq/kg,and 354–738 Bq/kg,respectively,with average values of(121±94)Bq/kg,(2.0±1.2)Bq/kg,(34±6)Bq/kg,(32±4)Bq/kg,(32±6)Bq/kg,(33±6)Bq/kg,and(611±119)Bq/kg.This study observed a significant positive correlation(r=0.845,p<0.05)between TOC and 210 Pb_(ex),highlighting the strong influence of organic matter on the distribution of 210 Pb_(ex).The boundary scavenging of210 Pb from the open sea contributed 27.5%–46.2%to the total 210 Pb_(ex) in the sediments of the outer Kongsfjorden.The grain size was an important factor affecting the activity distribution of several radionuclides(238 U,228 Ra,228 Th,226 Ra,and 40 K).The specific activity of 137 Cs indicated the transport of terrestrial materials from the exposed area of the Kongsfjorden.The sediments in the Kongsfjorden were derived from various material contributions of glacial meltwater debris,glacial rivers,bare soil,atmospheric deposition,and marine sources.This study explains the source of the Kongsfjorden sediment and the distribution characteristics of radionuclides,and illustrateas the main factors affecting the distribution of radionuclides,which provides a reference for the behavior of polar radionuclides in future research.