Climate warming has become evident in the maritime Antarctic over the past decades, and has already influenced the growing season and the population size of two native vascular plants in Antarctica, Deschampsia antarc...Climate warming has become evident in the maritime Antarctic over the past decades, and has already influenced the growing season and the population size of two native vascular plants in Antarctica, Deschampsia antarctica and Colobanthus quitensis. Both vascular plant species are therefore regarded as good bioindicators of regional warming in west Antarctica. To carry out long-term monitoring of vegetation （mainly using D. antarctica） and build a comprehensive research platform for multi-disciplinary study （including botany, microbiology, ecology, and environmental science） for Chinese scientists, 13 permanent plots were established in January and February of 2013-2015 in the area of Fildes Peninsula （King George Island）. Here we present the benchmark data of the first observations from these plots, including site characteristics, and the population and associates of D. antarctica in each plot. The basic data are important to understand the vegetation change, distribution range, and expansion of D. antarctica in Antarctica under future climate change scenarios.展开更多
The aim of the international project “Global Land Ice Measurements from Space (GLIMS)" headed by the US Geological Survey is to establish a world wide glacier inventory based on satellite imagery.This data set w...The aim of the international project “Global Land Ice Measurements from Space (GLIMS)" headed by the US Geological Survey is to establish a world wide glacier inventory based on satellite imagery.This data set will form a first digital baseline study for future glacier monitoring.The presented GIS_based glacier inventory for King George Island is a case study for the area of the Antarctic Peninsula.In the database of the glacier inventory topographic information,specific glaciological parameters as well as metadata will be included.The topographic data consists of drainage basin limits,basin areas,altitudinal ranges,perimeters and mean lengths.Glaciological data sets should comprise information on glacier retreat in different periods,glacier velocities,ice thickness and bedrock topography as well as derived parameters.Modelled and measured mass balance parameters could be included as additional data layers.In particular,these metadata records must comprise background information on data accuracy and data sources and should be compatible with a future data model for the King George Island GIS (KGIS).Three examples illustrate that the GLIMS database will not only contain information valuable for glaciological applications,but also other environmental studies on the island will benefit from this standardised remote sensing data sets.Therefore,a very close link between the data models of KGIS and GLIMS has to be established to enable these synergisms.Finally,better access to historic aerial photography would enable a continuous record of glacier retreat from the beginning of the 1950’s onward.展开更多
While the Antarctic Slope Current(ASC) has been intensively studied for the East Antarctica slope area and the Weddell Sea, its fate in the western Antarctic Peninsula(WAP) region remains much less known. Data from tw...While the Antarctic Slope Current(ASC) has been intensively studied for the East Antarctica slope area and the Weddell Sea, its fate in the western Antarctic Peninsula(WAP) region remains much less known. Data from two cruises conducted near the South Shetland Islands(SSIs) and the Elephant Island(EI), one in austral summer of 2004 and one in austral winter of 2006, were analyzed to provide a broad picture of the circulation pattern over the continental slope of the surveyed area, and an insight into the dynamical balance of the circulation. The results indicate that southwestward currents are present over the upper slope in the study area, indicating the ASC in the WAP region. Near the Shackleton Gap(SG) north of the EI, the southwestward slope currents near the shelf break are characterized by a water mass colder and fresher than the ambient water, which produces cross-slope density gradients and then vertical shear of the along-slope(or along-isobath) velocity. The vertical shear is associated with a reversal of the along-slope current from northeastward at surface to southwestward in deeper layers, or a depth-intensification of the southwestward slope currents. The water mass with temperature and salinity characteristics similar to the observed cold and fresh water is also revealed on the southern slope of the Scotia Sea, suggesting that this cold and fresh water is originated from the Scotia Sea slope and flows southwestward through the SG. Over the shelf north of the SSIs, the cold and fresh water mass is also observed and originates mainly from the Bransfield Strait. In this area, vertical structure of the southwestward slope currents is associated with the onshore intrusion of the upper Circumpolar Deep Water that creates cross-slope density gradients.展开更多
Diet components of Euphausia superba of 12 sexual maturity stages from the adjacent waters off the South Shetland Islands, Antarctica were analysed. The major points observed are summaried as follows: 135 taxa of nano...Diet components of Euphausia superba of 12 sexual maturity stages from the adjacent waters off the South Shetland Islands, Antarctica were analysed. The major points observed are summaried as follows: 135 taxa of nano- and microorganisms were found in stomach contents of Euphausia superba, of which, the diatoms make up 60% of the total species number. Planktonic nano- diatoms and nano- flagellates smaller than 20μm in diameter accounted for 85 % of diet total number. The dominant species in the stomach contents were Nitzschia angulata f. minima, N. curta f. minima, N. curta,Chrysostomum sp. , the mean cell number of these species was about 56. 99 cells/ind. , The stomach fullness increases gradually with the sexual mature of the krill.展开更多
This study aims to report baseline soil nutrients, specifically the organic carbon, nitrogen and phosphorus profile, in soil samples collected from Puntta Fort William on Greenwich Island in maritime Antarctic. Sample...This study aims to report baseline soil nutrients, specifically the organic carbon, nitrogen and phosphorus profile, in soil samples collected from Puntta Fort William on Greenwich Island in maritime Antarctic. Samples were collected along two transect lines during the early summer of 2008. Ward＇s method of hierarchical agglomerative clustering was employed to group the sampling points based on their physico-chemical properties. In this context, the soil samples can be grouped into three major clus- ters： （1） Samples with intensive biological activities, （2） samples from the area recently exposed by glacial retreat and （3） samples from barren and dried areas. Nutrient contents in Punta Fort William are driven by the intensity of biological activities as well as melt water from the Qnito glacier.展开更多
The submesoscale processes, including submesoscale eddies and fronts, have a strong vertical velocity, can thus make important supplements to the nutrients in the upper ocean. Using legacy multichannel seismic data AP...The submesoscale processes, including submesoscale eddies and fronts, have a strong vertical velocity, can thus make important supplements to the nutrients in the upper ocean. Using legacy multichannel seismic data AP25 of cruise EW9101 acquired northeast of the South Shetland Islands(Antarctic Peninsula) in February 1991, we identified an oceanic submesoscale eddy with the horizontal scale of ~4 km and a steep shelf break front that has variable dip angles from 5° to 10°. The submesoscale eddy is an anticyclonic eddy, which carries warm core water, can accelerate ice shelves melting. The upwelling induced by shelf break front may play an important role in transporting nutrients to the sea surface. The seismic images with very high lateral resolution may provide a new insight to understand the submesoscale and even small-scale oceanic phenomena in the interior.展开更多
Euphausia superba is a key species in the Southern Ocean that serves as a link between primary production and higher trophic levels.To investigate the feeding strategies of E.superba from the eastern South Shetland Is...Euphausia superba is a key species in the Southern Ocean that serves as a link between primary production and higher trophic levels.To investigate the feeding strategies of E.superba from the eastern South Shetland Islands,fatty acid biomarkers,stable isotope signatures,and an incubation experiment were conducted.The results of the incubation experiment proved that adult E.superba mainly fed on 2–20μm particles,demonstrating the importance of nanoplankton in their diet.Moreover,significant positive relationships betweenδ15N and body size demonstrated that size-related dietary shifts were present in E.superba.Evidence from principal component analysis and the C16:1ω7/C18:4ω3 ratio showed that juveniles preferentially fed on dinoflagellates and adults were more likely to feed on diatoms.Fatty acid profiles in adult E.superba roughly mirrored the different trophic conditions and feeding strategies between stations.Adult E.superba at Stas D2-07,D5-07,DA-01 and DA-02 exhibited elevated levels of C16:1ω7,C18:4ω3,C18:1ω9 and C18:1ω9/C18:1ω7,indicating higher levels of feeding on both phytoplankton and higher trophic diets.In contrast,adult E.superba at Stas D1-03 and D1-04 were characterized by high levels of polyunsaturated fatty acids/saturated fatty acids ratios and low levels of C16:1ω7,C18:1ω7,C18:4ω3,C18:1ω9 and total fatty acids.We inferred that adult krill at Stas D1-03 and D1-04 still suffered from difficult dietary conditions after overwintering.The different dietary conditions between stations suggest a highly plastic feeding strategy of E.superba in the eastern South Shetland Islands.展开更多
There is a zone of blastomylonites containing hornblende gneisses of Lewisian Inlier type in the northeast - east of Yell , Shetland . This zone with a north - northwesterly trend consists of blastomylonised hornblend...There is a zone of blastomylonites containing hornblende gneisses of Lewisian Inlier type in the northeast - east of Yell , Shetland . This zone with a north - northwesterly trend consists of blastomylonised hornblende - banded gneiss , hornblende - feldspar gneiss and mica - felsic - gneiss with lenses of hornblende gneiss . It is indicated that the blastomylonite zone is actually a ductile shear zone and the sense of shear is dextral . This contributes to understanding the details of tectonic evolution in this area , and this zone is probably a part of tectonic system of the British Caledonides .展开更多
Meiofaunal communities of three small, shallow freshwater habitats sampled during the austral summer of 2013 in Greenwich Island, South Shetland Islands, Antarctica, are reported. Communities are dominated by tardigra...Meiofaunal communities of three small, shallow freshwater habitats sampled during the austral summer of 2013 in Greenwich Island, South Shetland Islands, Antarctica, are reported. Communities are dominated by tardigrades （85%）, nematodes （11%）, and rotifers （3%）. Collembola, Oligochaeta, crustacean larvae （nauplii） and unidentified organisms account for 0.3%. Total meiofaunal densities reach 11 770 ind.cm^-2, with mean densities （ind.cm-2） of 1 365.83 ± 2 716.65 （Zone A）, 523.67 ± 1 166.48 （Zone B） and 72.17 ± 110.78 （Zone C）. Given the age of freshwater habitats, and the general lack of higher-tropbic level predatory taxa, those species we report are likely early stage colonizers, and these communities are at an early stage of ecological succession. Non-parametrical analysis revealed the main variables influencing meiofaunal density and distribution are related to granulometric characteristics of sediments and microphytobenthic biomass. There were close relationships between meiofaunal abundance and microphytobenthic biomass, which indicates that benthic microalgae significantly influence meiofaunal distribution. A strong correlation between nematode abundance and the percentage of silt, clay and carbon in the sediment was also shown by canonical correspondence analysis and Spearman rank correlation.展开更多
This study assessed the spatial distribution pa- ttern of soft-sediment polychaetes on the near-shore of Admiralty Bay, King George Island, Antarctica. In the early and late summer of 2003 /04, seven sites at three di...This study assessed the spatial distribution pa- ttern of soft-sediment polychaetes on the near-shore of Admiralty Bay, King George Island, Antarctica. In the early and late summer of 2003 /04, seven sites at three different depths (20,30 and 60 meters) were sampled using a van Veen grab. 8,668 individuals all told, belonging to 67 species and 23 families, were identified. The families Terebellidae, Syllidae and Maldanidae were the most speciose. Mean densities ranged from 45.2 to 388.1 ind. 0.1 m-2 in the early summer, and from 29 to 183 ind.0.1m-2 in the late. The species Aphelochaeta cincinnata, Levinsenia gracilis and Rhodine antarctica were the most frequent and abundant. Initially, mean biomass ranged from 0.11 to 5.27 g.0.1 m-2, in the early season and from 0.35 to 5.86 g.0.1 m-2 towards the end. Aglaophamus trissophyllus, Eupolymnia sp. and Barrukia cristata were the species with the highest biomass. Polychaete taxocoenosis structure remained similar in both periods. In the early summer, mean densities, biomass and number of species were lower at 30 meters and higher at 60, whereas in the late, these differences were higher among transects. Ice impacts, mainly anchor-ice, in the early summer, as well as icebergs later on, most likely caused the differences encountered.展开更多
This report provides a result obtained by the First Chinese Antarctic and Southern Ocean Expedition. Specimens were collected by investigators of the Second Institute of Oceanography, SOA, with plankton nets in Februa...This report provides a result obtained by the First Chinese Antarctic and Southern Ocean Expedition. Specimens were collected by investigators of the Second Institute of Oceanography, SOA, with plankton nets in February and March of 1985 from the South Shetland Islands, the Biscoe Islands and their vicinities, between 61°15'20S-65°30'16S, 56°18'72W-67°59'45W. Eight species belonging to 5 genera in 4 families have been identified, of which 4 species, namely Maupasia coeca Viguier, Rhyn-chonerella petersii (Langerhans), Rhynchonerella bongraini (Gravier), and Tomopteris planktonis Aps-tein are recorded for the first time from the South Shetland Islands and 2 species, namely Rhynchonerella bongraini (Gravier), and Tomopteris carpenteri Quatrefages are endemic species of Antarctica.展开更多
-STD Data obtained from the Third Chinese National Antarctic Research Expedition from January to February 1987 in the region near the South Shetland Islands are used to investigate an oceanic front, continental water ...-STD Data obtained from the Third Chinese National Antarctic Research Expedition from January to February 1987 in the region near the South Shetland Islands are used to investigate an oceanic front, continental water boundary (CWB), north of the South Shetland Islands. The characteristics of the CWB in surface and subsurface layers as well as deep layer are discussed respectively. The estimations of the geostrophic currents and the baroclinic deformed radius Rbc in this area show that the flow along the front is in the geostrophic equilibrium approximately, and the formation of the front is mainly due to the strong boundary current north of the South Shetland Islands. Its length along the front is estimated to be about 360 km and its width across the front is about 30 km.展开更多
In this paper, a distribution ol the oxygen-minimum layer in the sea area adjacent to the South Shetland Islands and north of the Ardleyd Island, Antarctica, in summer is discussed.The vertical distribution of oxygen ...In this paper, a distribution ol the oxygen-minimum layer in the sea area adjacent to the South Shetland Islands and north of the Ardleyd Island, Antarctica, in summer is discussed.The vertical distribution of oxygen in oxygen-minimum layer has the following features: 1). The depth at which the oxygen content greatly decreases is coincident with the depth of pycnocline; 2). There is a thick water layer with low oxygen content; 3). The oxygen-minimum layer occurs below the thermocline and coincides with the depth at which the temperature mostly increases. According to preliminary result of correlation analysis, the variation of oxygen-minimum layer is related to physical preperties of the circulation and biochemical process in deep layer of the ocean.展开更多
A total of 334 oriented volcanic samples of Early Tertiary were collected for a paleomagnetic study from 43 sampling sites in the South Shetland Islands,Antarctica.Paleomagnetic study indicates that the South Shetland...A total of 334 oriented volcanic samples of Early Tertiary were collected for a paleomagnetic study from 43 sampling sites in the South Shetland Islands,Antarctica.Paleomagnetic study indicates that the South Shetland Islands and Antarctic Peninsula were situated in or close to their present position in Early Tertiary. Furthermore, it is also suggested that a counterclockwise rotation about 15 degrees related to the relative movement between South America and Antarctica took place in north of Antarctic Peninsula since Paleocene.展开更多
Investigations were made on the microbes in the air, bottom sediments, surface seawater in the sea area of the South Shetland Islands during December, 1986～March, 1987.The results obtained show that: from the air ove...Investigations were made on the microbes in the air, bottom sediments, surface seawater in the sea area of the South Shetland Islands during December, 1986～March, 1987.The results obtained show that: from the air over the South Shetland Islands and the Maxwell Bay,the detection rate of terrigenous microbes was more than 90% and their amount was generally a few CFU/m3; the detection rate of marine microbes was more than 50% and their amount only 1 CFU/m3. The amounts of air-borne microbes over the surveyed area were the witness to their diurnal variations. They were influenced to some extent by nearby islands. Air temperature and relative humidity,etc. were factors affecting their quantitative variations.The bacterial amount of the outshore surface sea water in the Great Wall Bay, Antarctica was about n×10 CUF/cm3 (0≤n<10, the same below), the amount of microbes decreased with the monthly dropping of seawater temperature and showed a state of diurnal variations. The seawater in the Bay has been fairly clean. The microbial community consisted of at least thirteen genera,in which pseudomonas was common. In the intertidal zone of the Deception Island,there were only a few CFU of bacteria per cubic meter in seawater; and n×10 CFU/g (w. w) in the surface sediment;and n×10 CFU/g(w. w) in the volcano ash.The results reveal the general features of the microbes from the air,sea and land in the South Shetland Islands, Antarctica. It provides data for further study of microbial resources in that area.展开更多
基金financially supported by the National Natural Science Foundation of China (Grant no.41271222)Main Direction Program of Knowledge Innovation of Chinese Academy of Sciences (Grant no.KSCX2-EW-J-1)SKLSEB-IBCAS (Grant no.56176G1048)
文摘Climate warming has become evident in the maritime Antarctic over the past decades, and has already influenced the growing season and the population size of two native vascular plants in Antarctica, Deschampsia antarctica and Colobanthus quitensis. Both vascular plant species are therefore regarded as good bioindicators of regional warming in west Antarctica. To carry out long-term monitoring of vegetation （mainly using D. antarctica） and build a comprehensive research platform for multi-disciplinary study （including botany, microbiology, ecology, and environmental science） for Chinese scientists, 13 permanent plots were established in January and February of 2013-2015 in the area of Fildes Peninsula （King George Island）. Here we present the benchmark data of the first observations from these plots, including site characteristics, and the population and associates of D. antarctica in each plot. The basic data are important to understand the vegetation change, distribution range, and expansion of D. antarctica in Antarctica under future climate change scenarios.
文摘The aim of the international project “Global Land Ice Measurements from Space (GLIMS)" headed by the US Geological Survey is to establish a world wide glacier inventory based on satellite imagery.This data set will form a first digital baseline study for future glacier monitoring.The presented GIS_based glacier inventory for King George Island is a case study for the area of the Antarctic Peninsula.In the database of the glacier inventory topographic information,specific glaciological parameters as well as metadata will be included.The topographic data consists of drainage basin limits,basin areas,altitudinal ranges,perimeters and mean lengths.Glaciological data sets should comprise information on glacier retreat in different periods,glacier velocities,ice thickness and bedrock topography as well as derived parameters.Modelled and measured mass balance parameters could be included as additional data layers.In particular,these metadata records must comprise background information on data accuracy and data sources and should be compatible with a future data model for the King George Island GIS (KGIS).Three examples illustrate that the GLIMS database will not only contain information valuable for glaciological applications,but also other environmental studies on the island will benefit from this standardised remote sensing data sets.Therefore,a very close link between the data models of KGIS and GLIMS has to be established to enable these synergisms.Finally,better access to historic aerial photography would enable a continuous record of glacier retreat from the beginning of the 1950’s onward.
基金funded by the National Natural Science Foundation of China (No.41406006)sponsored by Shanghai Sailling Program (No.15FY1406400)
文摘While the Antarctic Slope Current(ASC) has been intensively studied for the East Antarctica slope area and the Weddell Sea, its fate in the western Antarctic Peninsula(WAP) region remains much less known. Data from two cruises conducted near the South Shetland Islands(SSIs) and the Elephant Island(EI), one in austral summer of 2004 and one in austral winter of 2006, were analyzed to provide a broad picture of the circulation pattern over the continental slope of the surveyed area, and an insight into the dynamical balance of the circulation. The results indicate that southwestward currents are present over the upper slope in the study area, indicating the ASC in the WAP region. Near the Shackleton Gap(SG) north of the EI, the southwestward slope currents near the shelf break are characterized by a water mass colder and fresher than the ambient water, which produces cross-slope density gradients and then vertical shear of the along-slope(or along-isobath) velocity. The vertical shear is associated with a reversal of the along-slope current from northeastward at surface to southwestward in deeper layers, or a depth-intensification of the southwestward slope currents. The water mass with temperature and salinity characteristics similar to the observed cold and fresh water is also revealed on the southern slope of the Scotia Sea, suggesting that this cold and fresh water is originated from the Scotia Sea slope and flows southwestward through the SG. Over the shelf north of the SSIs, the cold and fresh water mass is also observed and originates mainly from the Bransfield Strait. In this area, vertical structure of the southwestward slope currents is associated with the onshore intrusion of the upper Circumpolar Deep Water that creates cross-slope density gradients.
基金The Project Supported by National Natural Science Foundation of China, No:39000021
文摘Diet components of Euphausia superba of 12 sexual maturity stages from the adjacent waters off the South Shetland Islands, Antarctica were analysed. The major points observed are summaried as follows: 135 taxa of nano- and microorganisms were found in stomach contents of Euphausia superba, of which, the diatoms make up 60% of the total species number. Planktonic nano- diatoms and nano- flagellates smaller than 20μm in diameter accounted for 85 % of diet total number. The dominant species in the stomach contents were Nitzschia angulata f. minima, N. curta f. minima, N. curta,Chrysostomum sp. , the mean cell number of these species was about 56. 99 cells/ind. , The stomach fullness increases gradually with the sexual mature of the krill.
基金the Malaysian Antarctic Research Program(MARP)Ministry of Higher Education(MoHE),MalaysiaInstituto Antartico Ecuatoriano(INAE)for sponsoring the study
文摘This study aims to report baseline soil nutrients, specifically the organic carbon, nitrogen and phosphorus profile, in soil samples collected from Puntta Fort William on Greenwich Island in maritime Antarctic. Samples were collected along two transect lines during the early summer of 2008. Ward＇s method of hierarchical agglomerative clustering was employed to group the sampling points based on their physico-chemical properties. In this context, the soil samples can be grouped into three major clus- ters： （1） Samples with intensive biological activities, （2） samples from the area recently exposed by glacial retreat and （3） samples from barren and dried areas. Nutrient contents in Punta Fort William are driven by the intensity of biological activities as well as melt water from the Qnito glacier.
基金financially supported by National Polar Special Program “Impact and Response of Antarctic Seas to Climate Change” (Grant nos. IRASCC 01-03-01, 01-03-02)funded by the National Natural Science Foundation of China (Grant no. 41976048)the National Key R&D Program of China (Grant no. 2018YFC0310000)。
文摘The submesoscale processes, including submesoscale eddies and fronts, have a strong vertical velocity, can thus make important supplements to the nutrients in the upper ocean. Using legacy multichannel seismic data AP25 of cruise EW9101 acquired northeast of the South Shetland Islands(Antarctic Peninsula) in February 1991, we identified an oceanic submesoscale eddy with the horizontal scale of ~4 km and a steep shelf break front that has variable dip angles from 5° to 10°. The submesoscale eddy is an anticyclonic eddy, which carries warm core water, can accelerate ice shelves melting. The upwelling induced by shelf break front may play an important role in transporting nutrients to the sea surface. The seismic images with very high lateral resolution may provide a new insight to understand the submesoscale and even small-scale oceanic phenomena in the interior.
基金The National Natural Science Foundation of China under contract No.41406159the Science&Technology Basic Resources Investigation Program of China under contract No.2017FY100803+1 种基金the Chinese Polar Environment Comprehensive Investigation&Assessment Programmes under contract No.CHINARE2016-01-05the Scientific and Technological Innovation Project by Qingdao National Laboratory for Marine Science and Technology under contract No.2015ASKJ02
文摘Euphausia superba is a key species in the Southern Ocean that serves as a link between primary production and higher trophic levels.To investigate the feeding strategies of E.superba from the eastern South Shetland Islands,fatty acid biomarkers,stable isotope signatures,and an incubation experiment were conducted.The results of the incubation experiment proved that adult E.superba mainly fed on 2–20μm particles,demonstrating the importance of nanoplankton in their diet.Moreover,significant positive relationships betweenδ15N and body size demonstrated that size-related dietary shifts were present in E.superba.Evidence from principal component analysis and the C16:1ω7/C18:4ω3 ratio showed that juveniles preferentially fed on dinoflagellates and adults were more likely to feed on diatoms.Fatty acid profiles in adult E.superba roughly mirrored the different trophic conditions and feeding strategies between stations.Adult E.superba at Stas D2-07,D5-07,DA-01 and DA-02 exhibited elevated levels of C16:1ω7,C18:4ω3,C18:1ω9 and C18:1ω9/C18:1ω7,indicating higher levels of feeding on both phytoplankton and higher trophic diets.In contrast,adult E.superba at Stas D1-03 and D1-04 were characterized by high levels of polyunsaturated fatty acids/saturated fatty acids ratios and low levels of C16:1ω7,C18:1ω7,C18:4ω3,C18:1ω9 and total fatty acids.We inferred that adult krill at Stas D1-03 and D1-04 still suffered from difficult dietary conditions after overwintering.The different dietary conditions between stations suggest a highly plastic feeding strategy of E.superba in the eastern South Shetland Islands.
文摘There is a zone of blastomylonites containing hornblende gneisses of Lewisian Inlier type in the northeast - east of Yell , Shetland . This zone with a north - northwesterly trend consists of blastomylonised hornblende - banded gneiss , hornblende - feldspar gneiss and mica - felsic - gneiss with lenses of hornblende gneiss . It is indicated that the blastomylonite zone is actually a ductile shear zone and the sense of shear is dextral . This contributes to understanding the details of tectonic evolution in this area , and this zone is probably a part of tectonic system of the British Caledonides .
基金the Venezuelan Antarctic Program of the "Ministerio del Poder Popular para la Educacion Universitaria, Ciencia y Tecnologia"
文摘Meiofaunal communities of three small, shallow freshwater habitats sampled during the austral summer of 2013 in Greenwich Island, South Shetland Islands, Antarctica, are reported. Communities are dominated by tardigrades （85%）, nematodes （11%）, and rotifers （3%）. Collembola, Oligochaeta, crustacean larvae （nauplii） and unidentified organisms account for 0.3%. Total meiofaunal densities reach 11 770 ind.cm^-2, with mean densities （ind.cm-2） of 1 365.83 ± 2 716.65 （Zone A）, 523.67 ± 1 166.48 （Zone B） and 72.17 ± 110.78 （Zone C）. Given the age of freshwater habitats, and the general lack of higher-tropbic level predatory taxa, those species we report are likely early stage colonizers, and these communities are at an early stage of ecological succession. Non-parametrical analysis revealed the main variables influencing meiofaunal density and distribution are related to granulometric characteristics of sediments and microphytobenthic biomass. There were close relationships between meiofaunal abundance and microphytobenthic biomass, which indicates that benthic microalgae significantly influence meiofaunal distribution. A strong correlation between nematode abundance and the percentage of silt, clay and carbon in the sediment was also shown by canonical correspondence analysis and Spearman rank correlation.
文摘This study assessed the spatial distribution pa- ttern of soft-sediment polychaetes on the near-shore of Admiralty Bay, King George Island, Antarctica. In the early and late summer of 2003 /04, seven sites at three different depths (20,30 and 60 meters) were sampled using a van Veen grab. 8,668 individuals all told, belonging to 67 species and 23 families, were identified. The families Terebellidae, Syllidae and Maldanidae were the most speciose. Mean densities ranged from 45.2 to 388.1 ind. 0.1 m-2 in the early summer, and from 29 to 183 ind.0.1m-2 in the late. The species Aphelochaeta cincinnata, Levinsenia gracilis and Rhodine antarctica were the most frequent and abundant. Initially, mean biomass ranged from 0.11 to 5.27 g.0.1 m-2, in the early season and from 0.35 to 5.86 g.0.1 m-2 towards the end. Aglaophamus trissophyllus, Eupolymnia sp. and Barrukia cristata were the species with the highest biomass. Polychaete taxocoenosis structure remained similar in both periods. In the early summer, mean densities, biomass and number of species were lower at 30 meters and higher at 60, whereas in the late, these differences were higher among transects. Ice impacts, mainly anchor-ice, in the early summer, as well as icebergs later on, most likely caused the differences encountered.
文摘This report provides a result obtained by the First Chinese Antarctic and Southern Ocean Expedition. Specimens were collected by investigators of the Second Institute of Oceanography, SOA, with plankton nets in February and March of 1985 from the South Shetland Islands, the Biscoe Islands and their vicinities, between 61°15'20S-65°30'16S, 56°18'72W-67°59'45W. Eight species belonging to 5 genera in 4 families have been identified, of which 4 species, namely Maupasia coeca Viguier, Rhyn-chonerella petersii (Langerhans), Rhynchonerella bongraini (Gravier), and Tomopteris planktonis Aps-tein are recorded for the first time from the South Shetland Islands and 2 species, namely Rhynchonerella bongraini (Gravier), and Tomopteris carpenteri Quatrefages are endemic species of Antarctica.
文摘-STD Data obtained from the Third Chinese National Antarctic Research Expedition from January to February 1987 in the region near the South Shetland Islands are used to investigate an oceanic front, continental water boundary (CWB), north of the South Shetland Islands. The characteristics of the CWB in surface and subsurface layers as well as deep layer are discussed respectively. The estimations of the geostrophic currents and the baroclinic deformed radius Rbc in this area show that the flow along the front is in the geostrophic equilibrium approximately, and the formation of the front is mainly due to the strong boundary current north of the South Shetland Islands. Its length along the front is estimated to be about 360 km and its width across the front is about 30 km.
文摘In this paper, a distribution ol the oxygen-minimum layer in the sea area adjacent to the South Shetland Islands and north of the Ardleyd Island, Antarctica, in summer is discussed.The vertical distribution of oxygen in oxygen-minimum layer has the following features: 1). The depth at which the oxygen content greatly decreases is coincident with the depth of pycnocline; 2). There is a thick water layer with low oxygen content; 3). The oxygen-minimum layer occurs below the thermocline and coincides with the depth at which the temperature mostly increases. According to preliminary result of correlation analysis, the variation of oxygen-minimum layer is related to physical preperties of the circulation and biochemical process in deep layer of the ocean.
文摘A total of 334 oriented volcanic samples of Early Tertiary were collected for a paleomagnetic study from 43 sampling sites in the South Shetland Islands,Antarctica.Paleomagnetic study indicates that the South Shetland Islands and Antarctic Peninsula were situated in or close to their present position in Early Tertiary. Furthermore, it is also suggested that a counterclockwise rotation about 15 degrees related to the relative movement between South America and Antarctica took place in north of Antarctic Peninsula since Paleocene.
文摘Investigations were made on the microbes in the air, bottom sediments, surface seawater in the sea area of the South Shetland Islands during December, 1986～March, 1987.The results obtained show that: from the air over the South Shetland Islands and the Maxwell Bay,the detection rate of terrigenous microbes was more than 90% and their amount was generally a few CFU/m3; the detection rate of marine microbes was more than 50% and their amount only 1 CFU/m3. The amounts of air-borne microbes over the surveyed area were the witness to their diurnal variations. They were influenced to some extent by nearby islands. Air temperature and relative humidity,etc. were factors affecting their quantitative variations.The bacterial amount of the outshore surface sea water in the Great Wall Bay, Antarctica was about n×10 CUF/cm3 (0≤n<10, the same below), the amount of microbes decreased with the monthly dropping of seawater temperature and showed a state of diurnal variations. The seawater in the Bay has been fairly clean. The microbial community consisted of at least thirteen genera,in which pseudomonas was common. In the intertidal zone of the Deception Island,there were only a few CFU of bacteria per cubic meter in seawater; and n×10 CFU/g (w. w) in the surface sediment;and n×10 CFU/g(w. w) in the volcano ash.The results reveal the general features of the microbes from the air,sea and land in the South Shetland Islands, Antarctica. It provides data for further study of microbial resources in that area.
