This study was to investigate bacterial and archaeal community structure of pan-Arctic Ocean sediments by pyrosequencing. In total, investigation of three marine sediments revealed 15 002 bacterial and 4 362 archaeal ...This study was to investigate bacterial and archaeal community structure of pan-Arctic Ocean sediments by pyrosequencing. In total, investigation of three marine sediments revealed 15 002 bacterial and 4 362 archaeal operational taxonomic units （OTUs） at the 97% similarity level. Analysis of community structure indicated that these three samples had high bacterial and archaeal diversity. The most relatively abundant bacterial group in Samples CC 1 and R05 was Proteobacteria, while Firmicutes was dominant in Sample BL03. Thaumarchaeota was the most relatively abundant archaeal phylum in Samples CC1 and R05, and the relative abundance of Thaumarchaeota was almost as high as that of Euryarchaeota in Sample BL03. These two phyla accounted for nearly 100% of the archaeal OTUs. 6-Proteobacteria and y-Proteobacteria were the two most relatively abundant classes at Proteobacterial class level, and their relative abundance was more than 60% in Samples CC1 and R05. There were also differences in the top 10 relatively abundant bacterial and archaeal OTUs among the three samples at the 97% similarity, and only 12 core bacterial OTUs were detected. Overall, this study indicated that there were distinct microbial communities and many unique OTUs in these three samples.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
On the basis of observation of thin sections and ^137Cs data, laminations in sediment are interpreted to be varves in Bolterskardet Lake （78°06′ N, 16°01′ E）, Svalbard, the Arctic. Varves appear under a ...On the basis of observation of thin sections and ^137Cs data, laminations in sediment are interpreted to be varves in Bolterskardet Lake （78°06′ N, 16°01′ E）, Svalbard, the Arctic. Varves appear under a petrologic microscope as couplets of dark-silt and light-clay layers. The mechanism of varve formation is surmized as follows： each silt layer is the production of sediment inflow interpreted as mainly derived from snowmelt during summer; each clay layer was deposited in a stillwater environment during an ice-cover period. A light -clay layer provides an important index bed to identify the annual interface. The high accumulation rates, long period of ice cover, and topographically closed basin are probably all critical factors in forming and preserving varves. Varve thickness is known to be controlled mainly by summer temperature. The variation of varve thickness in Lake Bolterskardet can then be used to reconstruct summer temperature. The varve series show that there has been distinct decade-scale variability of summer temperature over the past 150 years. Warm periods occurred in the 1860s, around 1900, the 1930s, 1950s, and 1970s, and in the last 20 years. The varved sediments of Lake Bolterskarde preserve an ideal record for high-resolution paleoclimatic and paleoenvironmental research in this data-sparse area.展开更多
Bacterial diversity in surface sediment from the Arctic Ocean was investigated by culture-dependent and-independent approaches. Conventional culture-dependent techniques revealed 11 strains based on their distinct mor...Bacterial diversity in surface sediment from the Arctic Ocean was investigated by culture-dependent and-independent approaches. Conventional culture-dependent techniques revealed 11 strains based on their distinct morphological characteristics on marine Zobell 2216E agar plates. Phylogenetic analysis showed that these isolates belonged to three major lineages of the Bacteria,γ-proteobacteria, Bacteroidetes and Actinobacteria, and that they included 10 genera. Most isolates were psychrotrophic, and NaCl was not necessary for their growth. Furthermore, they exhibited activity of at least one extracellular hydrolytic enzyme at 4＆#176;C and had various abilities to assimilate carbon sources. A total of 67 phylotypes were detected among 142 clones based on the 16S rRNA library of the total community DNA and grouped into nine major lineages of bacteria. Phylotypes afifliated withγ-,δ-andε-proteobacteria accounted for 36.7%, 21.8%and 16.9%of the total clones, respectively. The rest of the clones belonged to Bacteroidetes,α-proteobacteria, Actinobacteria, Fusobacteria, Nitrospirae and an unclassiifed group.展开更多
Contaminants,such as polychlorinated biphenyls(PCBs),polycyclic aromatic hydrocarbons(PAHs),heavy metals,and per and polyfluoroalkyl substances(PFASs),primarily reach the Arctic through long-range atmospheric and ocea...Contaminants,such as polychlorinated biphenyls(PCBs),polycyclic aromatic hydrocarbons(PAHs),heavy metals,and per and polyfluoroalkyl substances(PFASs),primarily reach the Arctic through long-range atmospheric and oceanic transport.However,local sources within the Arctic also contribute to the levels observed in the environment,including legacy sources and new sources that arise from activities associated with increasing commercial and industrial development.The City of Iqaluit in Frobisher Bay,Nunavut(Canada),has seen rapid population growth and associated development during recent decades yet remains a site of interest for ocean protection,where Inuit continue to harvest country food.In the present study,seven dated marine sediment cores collected in Koojesse Inlet near Iqaluit,and from sites in inner and outer Frobisher Bay,respectively,were analyzed for total mercury(THg),major and trace elements,PAHs,PCBs,and PFASs.The sedimentary record in Koojesse Inlet shows a period of Aroclor 1260-like PCB input concurrent with military site presence in the 1950e60s,followed by decades of input of pyrogenic PAHs,averaging about ten times background levels.Near-surface sediments in Koojesse Inlet also show evidence of transient local-source inputs of THg and PFASs,and recycling or continued slow release of PCBs from legacy land-based sources.Differences in PFAS congener composition clearly distinguish the local sources from long-range transport.Outside Koojesse Inlet but still in inner Frobisher Bay,9.2 km from Iqaluit,sediments showed evidence of both local source(PCB)and longrange transport.In outer Frobisher Bay,an up-core increase in THg and PFASs in sediments may be explained by ongoing inputs of these contaminants from long-range transport.The context for ocean protection and country food harvesting in this region of the Arctic clearly involves both local sources and long-range transport,with past human activities leaving a long legacy insofar as levels of persistent organic pollutants are concerned.展开更多
基金The Chinese Polar Environment Comprehensive Investigation and Assessment Program under contract No.CHINARE2014-03-05the National Natural Science Foundation of China under contract No.41176174the Innovation and Development Regional Demonstration Program of Marine Economy under contract No.12PYY001SF08-HYYS-1
文摘This study was to investigate bacterial and archaeal community structure of pan-Arctic Ocean sediments by pyrosequencing. In total, investigation of three marine sediments revealed 15 002 bacterial and 4 362 archaeal operational taxonomic units （OTUs） at the 97% similarity level. Analysis of community structure indicated that these three samples had high bacterial and archaeal diversity. The most relatively abundant bacterial group in Samples CC 1 and R05 was Proteobacteria, while Firmicutes was dominant in Sample BL03. Thaumarchaeota was the most relatively abundant archaeal phylum in Samples CC1 and R05, and the relative abundance of Thaumarchaeota was almost as high as that of Euryarchaeota in Sample BL03. These two phyla accounted for nearly 100% of the archaeal OTUs. 6-Proteobacteria and y-Proteobacteria were the two most relatively abundant classes at Proteobacterial class level, and their relative abundance was more than 60% in Samples CC1 and R05. There were also differences in the top 10 relatively abundant bacterial and archaeal OTUs among the three samples at the 97% similarity, and only 12 core bacterial OTUs were detected. Overall, this study indicated that there were distinct microbial communities and many unique OTUs in these three samples.
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 Natural Science Foundation of China(Grant Nos.40472092,40352001)the Scientific Expedition Associationand the Yilite-Mulin Group,China.
文摘On the basis of observation of thin sections and ^137Cs data, laminations in sediment are interpreted to be varves in Bolterskardet Lake （78°06′ N, 16°01′ E）, Svalbard, the Arctic. Varves appear under a petrologic microscope as couplets of dark-silt and light-clay layers. The mechanism of varve formation is surmized as follows： each silt layer is the production of sediment inflow interpreted as mainly derived from snowmelt during summer; each clay layer was deposited in a stillwater environment during an ice-cover period. A light -clay layer provides an important index bed to identify the annual interface. The high accumulation rates, long period of ice cover, and topographically closed basin are probably all critical factors in forming and preserving varves. Varve thickness is known to be controlled mainly by summer temperature. The variation of varve thickness in Lake Bolterskardet can then be used to reconstruct summer temperature. The varve series show that there has been distinct decade-scale variability of summer temperature over the past 150 years. Warm periods occurred in the 1860s, around 1900, the 1930s, 1950s, and 1970s, and in the last 20 years. The varved sediments of Lake Bolterskarde preserve an ideal record for high-resolution paleoclimatic and paleoenvironmental research in this data-sparse area.
基金financially supported by the Public Science and Technology Funds for Ocean Projects(Grant nos.201005032-2 and 201205020-5)by the Special Funds for Basic Scientific Research by Central Non-profit Institutes(Grant no.GY02-2012G14)
文摘Bacterial diversity in surface sediment from the Arctic Ocean was investigated by culture-dependent and-independent approaches. Conventional culture-dependent techniques revealed 11 strains based on their distinct morphological characteristics on marine Zobell 2216E agar plates. Phylogenetic analysis showed that these isolates belonged to three major lineages of the Bacteria,γ-proteobacteria, Bacteroidetes and Actinobacteria, and that they included 10 genera. Most isolates were psychrotrophic, and NaCl was not necessary for their growth. Furthermore, they exhibited activity of at least one extracellular hydrolytic enzyme at 4＆#176;C and had various abilities to assimilate carbon sources. A total of 67 phylotypes were detected among 142 clones based on the 16S rRNA library of the total community DNA and grouped into nine major lineages of bacteria. Phylotypes afifliated withγ-,δ-andε-proteobacteria accounted for 36.7%, 21.8%and 16.9%of the total clones, respectively. The rest of the clones belonged to Bacteroidetes,α-proteobacteria, Actinobacteria, Fusobacteria, Nitrospirae and an unclassiifed group.
文摘Contaminants,such as polychlorinated biphenyls(PCBs),polycyclic aromatic hydrocarbons(PAHs),heavy metals,and per and polyfluoroalkyl substances(PFASs),primarily reach the Arctic through long-range atmospheric and oceanic transport.However,local sources within the Arctic also contribute to the levels observed in the environment,including legacy sources and new sources that arise from activities associated with increasing commercial and industrial development.The City of Iqaluit in Frobisher Bay,Nunavut(Canada),has seen rapid population growth and associated development during recent decades yet remains a site of interest for ocean protection,where Inuit continue to harvest country food.In the present study,seven dated marine sediment cores collected in Koojesse Inlet near Iqaluit,and from sites in inner and outer Frobisher Bay,respectively,were analyzed for total mercury(THg),major and trace elements,PAHs,PCBs,and PFASs.The sedimentary record in Koojesse Inlet shows a period of Aroclor 1260-like PCB input concurrent with military site presence in the 1950e60s,followed by decades of input of pyrogenic PAHs,averaging about ten times background levels.Near-surface sediments in Koojesse Inlet also show evidence of transient local-source inputs of THg and PFASs,and recycling or continued slow release of PCBs from legacy land-based sources.Differences in PFAS congener composition clearly distinguish the local sources from long-range transport.Outside Koojesse Inlet but still in inner Frobisher Bay,9.2 km from Iqaluit,sediments showed evidence of both local source(PCB)and longrange transport.In outer Frobisher Bay,an up-core increase in THg and PFASs in sediments may be explained by ongoing inputs of these contaminants from long-range transport.The context for ocean protection and country food harvesting in this region of the Arctic clearly involves both local sources and long-range transport,with past human activities leaving a long legacy insofar as levels of persistent organic pollutants are concerned.
