The Pb concentrations of atmospheric aerosol in the Chukchi Sea of the Arctic vary within the range of 0.167- 0.962 ng/m3, with an average of 0.532 ng/m3. These concentration values are 200 times higher than the natur...The Pb concentrations of atmospheric aerosol in the Chukchi Sea of the Arctic vary within the range of 0.167- 0.962 ng/m3, with an average of 0.532 ng/m3. These concentration values are 200 times higher than the natural background values of snow samples there. Calculation of the Pb enrichment factor of aerosol indicates that the ocean- and continent-source lead account for 9.23% and 0.01%, respectively, but industrially released Pb accounts for more than 90% of the atmospheric Pb. The Pb isotopic composition of aerosol has revealed that the sources of lead from industrial lead that causes pollution include mainly the western part of North America, East Europe and the former Soviet Union. The calculation of the total fallout flux of Pb indicates that the mean value of input flux into the Chukchi Sea is 0.02 mgm -2a -1,equivalent to that of southern Pacific but slightly lower than that of northern Indian Sea and southern Atlantic. It is evidenced that the Pb input flux into the Chukchi Sea is far lower than that off the Baltic Sea, the North Sea and the Mediterranean Sea.展开更多
The content of organic carbon （OC） normalized to the specific surface area （SSA） of sediment is widely used to trace variations in OC loading （OC/SSA）. This study presents observations of OC/SSA of surface sedim...The content of organic carbon （OC） normalized to the specific surface area （SSA） of sediment is widely used to trace variations in OC loading （OC/SSA）. This study presents observations of OC/SSA of surface sediments collected in the Chukchi Sea, a typical Arctic marginal sea. Shelf sediments exhibit much higher OC/SSA values than slope sediments in the study area. Compared with OC/SSA values reported from the East Siberian Shelf and Mackenzie River, the slope sediments possess lower OC loading. This abrupt decrease in OC/SSA is mostly related to the lower primary production on slope as well as possible oxidization processes. The results of linear regression analysis between OC and SSA indicate a sedimentary source rock for the OC in the Chukchi Sea sediments. Moreover, shelf sediments with low SSA possess a larger rock OC fraction than slope sediments do. The dataset of the present study enables a more thorough understanding of regional OC cycling in the Chukchi Sea.展开更多
Pacific water exits the Chukchi Sea shelf through Barrow Canyon in the east and Herald Canyon in the west, forming an eastward-directed shelfbreak boundary current that flows into the Beaufort Sea. Here we summarize t...Pacific water exits the Chukchi Sea shelf through Barrow Canyon in the east and Herald Canyon in the west, forming an eastward-directed shelfbreak boundary current that flows into the Beaufort Sea. Here we summarize the transformation that the Pacific water undergoes in the two canyons, and describe the characteristics and variability of the resulting shelfbreak jet, using recently collected summertime hydrographic data and a year-long mooting data set. In both canyons the northward-flowing Pacific winter water switches from the western to the eastern flank of the canyon, interacting with the northward-flowing summer water. In Barrow canyon the vorticity structure of the current is altered, while in Herald canyon a new water mass mode is created. In both instances hydraulic effects are believed to be partly responsible for the observed changes. The shelfl）reak jet that forms from the canyon outflows has distinct seasonal configurations, from a bottom-intensified flow carrying cold, dense Pacific water in spring, to a surface-intensified current advecting warm, buoyant water in summer. The current also varies significantly on short timescales, from less than a day to a week. In fall and winter much of this mesoscale variability is driven by storm events, whose easterly winds reverse the current and cause upwelling. Different types of eddies are spawned from the current, which are characterized here using hydrographic and satellite data.展开更多
During the summer of 2008, the third CHINARE Arctic Expedition was carried out on board of Xuelong Icebreaker in the central Chukchi Sea. A submersible mooring system was deployed and recovered at Station CN-01 （71.4...During the summer of 2008, the third CHINARE Arctic Expedition was carried out on board of Xuelong Icebreaker in the central Chukchi Sea. A submersible mooring system was deployed and recovered at Station CN-01 （71.40.024＇N, 167.58.910＇W） with 33 days of the current profile records, and continuous observation of temperature and salinity data were collected. This mooring station locates in the blank of similar observation area and it is the first time for our Chinese to finish this kind of long-term mooring work in this area. This mooring system finished integrated hydrological observations with long-term continuous record of the whole profile velocity for the first time. Based on time series analysis of temperature, salinity, velocity and flow direction, we get the following main results. （1） During the observation period, the mean surface current velocity is 70.2 cm/s eastward, and velocity reaches its maximum in average at 3 m level with magnitude 90.0 cm/s, direction 206.. （2） In 9-30 m layers, the semidiurnal period variation is the most obvious, the flow direction is quite stable, and the flow is synchronous and consistent vertically. （3） Besides the semidiurnal period variation, the main variation in the upper layer is in 11-d period, with variations in period 5.5, 5.5, and 3.7 d, which reflect the influences of sea surface wind change and maintenance. （4） Near the bottom the temperature change is correlated and synchronized with the conductivity.展开更多
There are awareness and concerns caused by the decreasing sea ice coverage around the Arctic and Antarctic due to effects of climate change. Emphasis in this study was on rapid changes in Arctic sea ice coverage and i...There are awareness and concerns caused by the decreasing sea ice coverage around the Arctic and Antarctic due to effects of climate change. Emphasis in this study was on rapid changes in Arctic sea ice coverage and its impacts on the marine ecology during the fourth Chinese National Arctic Research Expedition in 2010. Our purpose was to establish a baseline of Arctic fish compositions, and consequent effects of climate change on the fish community and biogeography. Fish specimens were col- lected using a multinet middle-water trawl, French-type beam trawl, otter trawl, and triangular bottom trawl. In total, 36 tows were carried out along the shelf of the Bering Sea, Bering Strait, and Chukchi Sea in the Arctic Ocean. in total, 41 fish species belonging to 14 families in 7 orders were collected during the expedition. Among them, the Scorpaeniformes, including 17 species, accounted for almost one third of the total number （34.8%）, followed by 14 species of the Perciformes （27.0%）, 5 species of the Pleuronecti- formes （22.3%）, and 2 species of the Gadiformes （15.4%）. The top 6 most abundant species were Hippoglossoides robustus, Bore- gadus saida, Myoxocephalus scorpius, Lumpenus fabricii, Artediellus scaber, and Gymnoeanthus trieuspis. Abundant species var- ied according to the different fishing methods; numbers of families and species recorded did not differ with the various fishing methods; species and abundances decreased with depth and latitude; and species extending over their known geographic ranges were observed during the expedition. Station information, species list, and color photographs of all fishes are provided.展开更多
We evaluated the relationships between water masses and pico- and nano-phytoplankton and bacterial abundance in the Chukchi Sea. The abundance of picoplankton ranged from 0.01 ~ 103 cells.mL1 （100 m, station R05） to...We evaluated the relationships between water masses and pico- and nano-phytoplankton and bacterial abundance in the Chukchi Sea. The abundance of picoplankton ranged from 0.01 ~ 103 cells.mL1 （100 m, station R05） to 2.21 x 103 cells.mL-1 （10 m, station R05） and that of nanoplankton ranged from 0.03 x 103 cells.mL-I （100 m, station R07） to 2.21 ~ 104 cells.mLq （10 m, station R05）. The lowest abundance of bacteria in the whole water column （0.21 x 106 cells.mLq） was at 100 m at station R17, and the highest （9.61 x 106 cells.mLL） was at 10 m at station R09. Melting sea ice affected the physical characteristics of the Chukchi Sea by reducing salinity of the surface mixed layer, resulting in greater hydrodynamic stability of the water column. These changes were accompanied by increased bacterial abundance. The warm Pacific water brought nutrients into the Chukchi Sea, resulting in greater abundance of bacteria and nano-phytoplankton in the Chukchi Sea than in other regions of the Arctic Ocean. However, the abundance of pico-phytoplankton, which was related to chlorophyll a concentration, was higher in Anadyr water than in the other two water masses. The structures ofpico- and nanoplankton communities coupled with the water masses in the Chuk- chi Sea can serve as indicators of the inflow of warm Pacific water into the Chukchi Sea.展开更多
This paper determined the abundance of General Aerobic heterotrophic Bacteria （GAB） in surficial sediments from the Chukchi Sea and the Canadian basin by using MPN and discussed their geographical distribution. The ...This paper determined the abundance of General Aerobic heterotrophic Bacteria （GAB） in surficial sediments from the Chukchi Sea and the Canadian basin by using MPN and discussed their geographical distribution. The result shows that the determination percentages of the GAB were high, even till 100 percentage. The abundance range and averages of GAB for 4℃and 25℃ were from 4.00 × 10^2 to 2.40× 10^6 , 1.71×10^6 ind.·g^-1 （wet sample ） and from 2.40 ×10^5 to 2.40×10^7 , 1.10×10^7 ind. ·g^-1 （wet sample ） respectively. Not only the abundance range but also the averages of GAB in 25℃ were higher than that in 4℃. The abundance of GAB in sediments show a tendency that it is roughly greater in the lower latitudinal area than in the higher latitudinal area. The abundance of GAB increased from east to west as for the longitudinal distribution. With the water depth increasing, the abundance of GAB at 4℃ decreased, but GBA at 25℃ is not changed obviously with water depth. It seems that warmer circumstantial temperature is more suitable for some GAB.展开更多
文摘The Pb concentrations of atmospheric aerosol in the Chukchi Sea of the Arctic vary within the range of 0.167- 0.962 ng/m3, with an average of 0.532 ng/m3. These concentration values are 200 times higher than the natural background values of snow samples there. Calculation of the Pb enrichment factor of aerosol indicates that the ocean- and continent-source lead account for 9.23% and 0.01%, respectively, but industrially released Pb accounts for more than 90% of the atmospheric Pb. The Pb isotopic composition of aerosol has revealed that the sources of lead from industrial lead that causes pollution include mainly the western part of North America, East Europe and the former Soviet Union. The calculation of the total fallout flux of Pb indicates that the mean value of input flux into the Chukchi Sea is 0.02 mgm -2a -1,equivalent to that of southern Pacific but slightly lower than that of northern Indian Sea and southern Atlantic. It is evidenced that the Pb input flux into the Chukchi Sea is far lower than that off the Baltic Sea, the North Sea and the Mediterranean Sea.
基金The National Natural Science Foundation of China under contract Nos 41606211,41276198,41406217 and 41306200the China Polar Environment Comprehensive Investigation and Assessment Programs under contract Nos Chinare-03-04 and Chinare-04-03+1 种基金the National Science Foundation for Post-doctoral Scientists of China under contract No.2016M591968the Scientific Research Fund of Second Institute of Oceanography,SOA under contract No.JG1502
文摘The content of organic carbon （OC） normalized to the specific surface area （SSA） of sediment is widely used to trace variations in OC loading （OC/SSA）. This study presents observations of OC/SSA of surface sediments collected in the Chukchi Sea, a typical Arctic marginal sea. Shelf sediments exhibit much higher OC/SSA values than slope sediments in the study area. Compared with OC/SSA values reported from the East Siberian Shelf and Mackenzie River, the slope sediments possess lower OC loading. This abrupt decrease in OC/SSA is mostly related to the lower primary production on slope as well as possible oxidization processes. The results of linear regression analysis between OC and SSA indicate a sedimentary source rock for the OC in the Chukchi Sea sediments. Moreover, shelf sediments with low SSA possess a larger rock OC fraction than slope sediments do. The dataset of the present study enables a more thorough understanding of regional OC cycling in the Chukchi Sea.
基金supported by the National Science Foundation under grants OPP-0731928 and OPP-0713250.
文摘Pacific water exits the Chukchi Sea shelf through Barrow Canyon in the east and Herald Canyon in the west, forming an eastward-directed shelfbreak boundary current that flows into the Beaufort Sea. Here we summarize the transformation that the Pacific water undergoes in the two canyons, and describe the characteristics and variability of the resulting shelfbreak jet, using recently collected summertime hydrographic data and a year-long mooting data set. In both canyons the northward-flowing Pacific winter water switches from the western to the eastern flank of the canyon, interacting with the northward-flowing summer water. In Barrow canyon the vorticity structure of the current is altered, while in Herald canyon a new water mass mode is created. In both instances hydraulic effects are believed to be partly responsible for the observed changes. The shelfl）reak jet that forms from the canyon outflows has distinct seasonal configurations, from a bottom-intensified flow carrying cold, dense Pacific water in spring, to a surface-intensified current advecting warm, buoyant water in summer. The current also varies significantly on short timescales, from less than a day to a week. In fall and winter much of this mesoscale variability is driven by storm events, whose easterly winds reverse the current and cause upwelling. Different types of eddies are spawned from the current, which are characterized here using hydrographic and satellite data.
基金The National Key Basic Research and Development Plan under contract No. 2010CB950301:"Sea-ice-air interaction in the Southern Ocean and its influence on the south Indian Ocean",International Polar Year Chinese action plan project:"Chukchi Sea & Beaufort Sea ice anomaly variation and its impact on the winter climate of China"National Science and Technology Support Program under contract No.2006BAB18B02:"Water masses and circulation monitoring technology and its application in the southern ocean"The Basic Research Fund Project under contract No.FIO SOA 2010T01:"Key technology research of polar mooring observation system"
文摘During the summer of 2008, the third CHINARE Arctic Expedition was carried out on board of Xuelong Icebreaker in the central Chukchi Sea. A submersible mooring system was deployed and recovered at Station CN-01 （71.40.024＇N, 167.58.910＇W） with 33 days of the current profile records, and continuous observation of temperature and salinity data were collected. This mooring station locates in the blank of similar observation area and it is the first time for our Chinese to finish this kind of long-term mooring work in this area. This mooring system finished integrated hydrological observations with long-term continuous record of the whole profile velocity for the first time. Based on time series analysis of temperature, salinity, velocity and flow direction, we get the following main results. （1） During the observation period, the mean surface current velocity is 70.2 cm/s eastward, and velocity reaches its maximum in average at 3 m level with magnitude 90.0 cm/s, direction 206.. （2） In 9-30 m layers, the semidiurnal period variation is the most obvious, the flow direction is quite stable, and the flow is synchronous and consistent vertically. （3） Besides the semidiurnal period variation, the main variation in the upper layer is in 11-d period, with variations in period 5.5, 5.5, and 3.7 d, which reflect the influences of sea surface wind change and maintenance. （4） Near the bottom the temperature change is correlated and synchronized with the conductivity.
基金supported by the China Program for International Polar Year 2007-2011the Special Research Foundation for Public Welfare Marine Program (Grant no.201105022-2)
文摘There are awareness and concerns caused by the decreasing sea ice coverage around the Arctic and Antarctic due to effects of climate change. Emphasis in this study was on rapid changes in Arctic sea ice coverage and its impacts on the marine ecology during the fourth Chinese National Arctic Research Expedition in 2010. Our purpose was to establish a baseline of Arctic fish compositions, and consequent effects of climate change on the fish community and biogeography. Fish specimens were col- lected using a multinet middle-water trawl, French-type beam trawl, otter trawl, and triangular bottom trawl. In total, 36 tows were carried out along the shelf of the Bering Sea, Bering Strait, and Chukchi Sea in the Arctic Ocean. in total, 41 fish species belonging to 14 families in 7 orders were collected during the expedition. Among them, the Scorpaeniformes, including 17 species, accounted for almost one third of the total number （34.8%）, followed by 14 species of the Perciformes （27.0%）, 5 species of the Pleuronecti- formes （22.3%）, and 2 species of the Gadiformes （15.4%）. The top 6 most abundant species were Hippoglossoides robustus, Bore- gadus saida, Myoxocephalus scorpius, Lumpenus fabricii, Artediellus scaber, and Gymnoeanthus trieuspis. Abundant species var- ied according to the different fishing methods; numbers of families and species recorded did not differ with the various fishing methods; species and abundances decreased with depth and latitude; and species extending over their known geographic ranges were observed during the expedition. Station information, species list, and color photographs of all fishes are provided.
基金supported by the National Natural Science Foundation of China (Grant no.41076130)
文摘We evaluated the relationships between water masses and pico- and nano-phytoplankton and bacterial abundance in the Chukchi Sea. The abundance of picoplankton ranged from 0.01 ~ 103 cells.mL1 （100 m, station R05） to 2.21 x 103 cells.mL-1 （10 m, station R05） and that of nanoplankton ranged from 0.03 x 103 cells.mL-I （100 m, station R07） to 2.21 ~ 104 cells.mLq （10 m, station R05）. The lowest abundance of bacteria in the whole water column （0.21 x 106 cells.mLq） was at 100 m at station R17, and the highest （9.61 x 106 cells.mLL） was at 10 m at station R09. Melting sea ice affected the physical characteristics of the Chukchi Sea by reducing salinity of the surface mixed layer, resulting in greater hydrodynamic stability of the water column. These changes were accompanied by increased bacterial abundance. The warm Pacific water brought nutrients into the Chukchi Sea, resulting in greater abundance of bacteria and nano-phytoplankton in the Chukchi Sea than in other regions of the Arctic Ocean. However, the abundance of pico-phytoplankton, which was related to chlorophyll a concentration, was higher in Anadyr water than in the other two water masses. The structures ofpico- and nanoplankton communities coupled with the water masses in the Chuk- chi Sea can serve as indicators of the inflow of warm Pacific water into the Chukchi Sea.
基金the national ministry of finance。the second Arctic research expedition（CHINARE-2003）National Natural Science Foundation of China（No.40576060, 40376017 and 40176017）.
文摘This paper determined the abundance of General Aerobic heterotrophic Bacteria （GAB） in surficial sediments from the Chukchi Sea and the Canadian basin by using MPN and discussed their geographical distribution. The result shows that the determination percentages of the GAB were high, even till 100 percentage. The abundance range and averages of GAB for 4℃and 25℃ were from 4.00 × 10^2 to 2.40× 10^6 , 1.71×10^6 ind.·g^-1 （wet sample ） and from 2.40 ×10^5 to 2.40×10^7 , 1.10×10^7 ind. ·g^-1 （wet sample ） respectively. Not only the abundance range but also the averages of GAB in 25℃ were higher than that in 4℃. The abundance of GAB in sediments show a tendency that it is roughly greater in the lower latitudinal area than in the higher latitudinal area. The abundance of GAB increased from east to west as for the longitudinal distribution. With the water depth increasing, the abundance of GAB at 4℃ decreased, but GBA at 25℃ is not changed obviously with water depth. It seems that warmer circumstantial temperature is more suitable for some GAB.
