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Sample records for fildes strait antarctica

  1. Holocene environmental change according to lake core in Fildes Peninsula of King George Island, Antarctica

    Institute of Scientific and Technical Information of China (English)

    李小梅; 袁宝印; 赵俊琳

    2002-01-01

    Lake core sampled from Xihu in Fildes Peninsula of King Gorge Island, Antarctica could reveal the environmental change of the district. The lake core(GA7) , 9.28 meters long ,was sectioned at an interval of 2 cm. Through measuring the organic carbon, magnetic susceptibility, granularity and organic carbon isotope of GA7, by use of 14C age it was estimated that there were four periods of high temperature in Fildes Peninsula: 4800-4400 aB.P., 3600-3350 aB.P.,2100-1800 aB.P. and 900 aB.P. - present. Meanwhile, results showed that there was a strikingly positive correlation between the content of organic carbon and that of organic carbon isotope(δC13org) which could be the substitute indicators of environmental temperature.

  2. Preliminary evidence for 17 coastal terraces on Fildes Peninsula, King George Island, Antarctica

    Institute of Scientific and Technical Information of China (English)

    CHU Zhuding; YIN Xuebin; SUN Liguang; WANG Yuhong

    2015-01-01

    This study confirms the presence of 17 coastal terraces on Fildes Peninsula, Antarctica based on field observations and grain size analysis. The terraces formed by isostatic uplift during climate warming and glacier melting, and each level corresponds to a relatively stable period of climate. The grain size characteristics indicate an overlapping sedimentary origin for the sediments on the coastal terraces. The consistency of regional sea level rise, climate change, and glacial area suggest the presence of similar coastal terraces on King George Island since 18.0 ka.

  3. DISCOVERY OF LATE CRETACEOUS PALYNOFLORA FROM FILDES PENINSULA, KING GEORGE ISLAND, ANTARCTICA AND ITS SIGNIFICANCE

    Institute of Scientific and Technical Information of China (English)

    1990-01-01

    This paper makes an analysis and study on altogether 8 palyniferous samples from the volcano-sedimentary rock series in the Half Three Point area of the Fildes Peninsula, King George Island, Antarctica, the rock series being grey tuffaceous siltstone in lithological characters, about 5m in thickness. Only after making a number of analyses, could we find the relatively abundant sporopollen fossils from 4 samples (Nos. GWP 4—7). But the fossils are poorly preserved, and most of them can hardly be identifi...

  4. Monitoring the concentration of N2O in the Fildes Peninsula, maritime Antarctica

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Gases in the marine boundary layer in Fildes Peninsula, maritime Antarctica were sampled and analyzed for the first time. Sampling sites included areas covered by moss and lichen growth, penguin colonies and an area where scientific research stations are located. A total of 211 samples were analyzed for N2O concentrations, with an average of (321.33±3.07) nL/L. This is above the global average value of 314 nL/L. It is found that the N2O concentrations evidently increase during the summer months. Concentrations around the research stations are higher than at remote areas, indicating a potential source from human activities on the island. N2O concentrations at a large penguin colony on Barton Peninsula are the highest among the sampled areas. This may explain why N2O concentrations in Fildes Peninsula are higher than the global average. Our preliminary conclusions are that human activities and emissions from penguin dropping-amended soil and vegetation soil constitute the major sources of N2O in the maritime Antarctic atmosphere.

  5. Molecular organic geochemical peculiarities of lacustrine core sediments in Fildes Peninsula, King George Island,Antarctica

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The peculiarities of lipids in lacustrine core sediments from Fildes Peninsula, King George Island, Antarctica, are reported. The origin of high-molecular-weight n-alkanes, alkenes,fatty acids, alcohols is supposed to be related to the abundant moss occurring in the sediments.Abundant iso-and anteiso-fatty acids that occur in the sediments indicate a relatively strong bacterial activity in non-ice-cover zone than in other regions in Antarctica. The C18:2 unsaturated fatty acids mainly originate from autochthonous algae in the sediment pool, and the C18:2/C18:0ratios in the profile are controlled more by paleotemperatures than source assemblies. Long-chain alkenones were identified in freshwater lacustrine sediment in Antarctica for the first time, of which Prymnesiophyceae is assumed to be the source organism. High relative abundance of C37:4honologue in long-chain alkenone well correlates to the severely cold climate in Antarctica.

  6. A 2500-year sea level change record in Fildes Peninsula, Antarctica

    Institute of Scientific and Technical Information of China (English)

    ZHAO Ye

    2004-01-01

    A detailed record of sea level changes during the last 2500 years is preserved in the northernwest coast of Fildes Peninsula in Antarctica. Fourteen marine alga layers were deposited in the beach with an altitude of 2.80 m, and one diatom layer deposited in the ancient lake on the terrace with an altitude of 6.84 m. A radiocarbon age of 695±70 aBP was obtained for the modern marine alga, and the age was used in correction for the carbon reservoir effect of the marine alga. Sea level fell 4.98 m from the 4th century B.C. to the early 13th century, at an average of -0.31 cm/a, then rose about 0.78 m during the early 13th to the middle 18th century, at an average of 0.14 cm/a. It has risen about 0.16 m since the middle 18th century, at an average of 0.07 cm/a.

  7. Richness and bioactivity of culturable soil fungi from the Fildes Peninsula, Antarctica.

    Science.gov (United States)

    Ding, Zhuang; Li, Liyuan; Che, Qian; Li, Dehai; Gu, Qianqun; Zhu, Tianjiao

    2016-07-01

    Since the discovery of penicillin, fungi have been an important source of bioactive natural products. However, as a specific resource, the bioactive potentiality and specificity of fungal metabolites from the Antarctic region have had little attention. In this paper, we investigated the diversity patterns and biological activities of cultivable fungi isolated from soil samples in Fildes Peninsula, King George Island, Antarctica. Fungal communities showed low abundance and diversity; a total of 150 cultivable fungi were isolated from eight soil samples. After being dereplicated by morphological characteristics and chemical fingerprints, 47 fungal isolates were identified by ITS-rDNA sequencing. We confirmed that these isolates belonged to at least 11 different genera and clustered into nine groups corresponding to taxonomic orders in the phylogenetic analysis. Using two different fermentation conditions, 94 crude extracts acquired from the abovementioned different metabolite characteristic isolates were screened by bioactivity assay and 18 isolates produced biologically active compounds. Compared with HPLC-DAD-UV fingerprint analysis of culture extracts and standard compounds, two bioactive components secalonic acid and chetracins were identified. Our research suggests that the abundance and diversity of Antarctic cultivable fungal communities exhibit unique ecological characteristics and potential producers of novel natural bioactive products.

  8. Distribution patterns of typical enzyme activities in tundra soils on the Fildes Peninsula of maritime Antarctica

    Institute of Scientific and Technical Information of China (English)

    DING Wei; WANG Qing; ZHU Renbin; MA Dawei

    2015-01-01

    Soil enzyme activities can be used as indicators of microbial activity and soil fertility. In this paper, the activities of invertase (IA), phosphatase (PA) and urease (UA) were investigated in tundra soils collected from marine animal colonies, areas of human activity and background areas on Fildes Peninsula, maritime Antarctica. Soil enzyme activities were in the range of 1.0–82.7 mg·kg-1·h-1 for IA, 0.2–8.2 mg·kg-1·h-1 for PA and 0.2–39.8 mg·kg-1·h-1 for UA. The spatial distribution patterns for soil enzyme activities corresponded strongly with marine animal activity and human activity. Significantly higher soil IA and PA activities occurred in penguin colony soils, whereas seal colony soils showed higher UA activity. Statistical analysis indicated that soil IA activity was controlled by the levels of soil nutrients (TOC, TN and TP), PA activity was closely related with TP, and UA activity was affected by the soil pH. Overall, the deposition amount of penguin guano or seal excreta could impact the distribution of enzyme activity in Antarctic tundra soils. Multiple stepwise regression models were established between the enzyme activities, soil physicochemical properties and heavy metals Cu and Zn ([IA]=0.7[TP]–0.2[Cu]+22.3[TN]+15.1, [PA]=0.3[TP]+0.03[Mc]+0.2, [UA]=16.7[pH]–0.5[Cu]+ 0.4[Zn]–72.6). These models could be used to predict enzyme activities in the tundra soils, which could be helpful to study the effects of marine animal activity and environmental change on tundra ecosystems in maritime Antarctica.

  9. Active layer thermal monitoring at Fildes Peninsula, King George Island, Maritime Antarctica

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    R. F. M. Michel

    2014-07-01

    Full Text Available International attention to the climate change phenomena has grown in the last decade; the active layer and permafrost are of great importance in understanding processes and future trends due to their role in energy flux regulation. The objective of the this paper is to present active layer temperature data for one CALM-S site located at Fildes Peninsula, King George Island, Maritime Antarctica over an fifth seven month period (2008–2012. The monitoring site was installed during the summer of 2008 and consists of thermistors (accuracy of ± 0.2 °C, arranged vertically with probes at different depths, recording data at hourly intervals in a~high capacity data logger. A series of statistical analysis were performed to describe the soil temperature time series, including a linear fit in order to identify global trend and a series of autoregressive integrated moving average (ARIMA models were tested in order to define the best fit for the data. The controls of weather on the thermal regime of the active layer have been identified, providing insights about the influence of climate chance over the permafrost. The active layer thermal regime in the studied period was typical of periglacial environment, with extreme variation at the surface during summer resulting in frequent freeze and thaw cycles. The active layer thickness (ALT over the studied period showed variability related to different annual weather conditions, reaching a maximum of 117.5 cm in 2009. The ARIMA model was considered appropriate to treat the dataset, enabling more conclusive analysis and predictions when longer data sets are available. Despite the variability when comparing temperature readings and active layer thickness over the studied period, no warming trend was detected.

  10. GEODESY AND DIGITAL CARTOGRAPHIC SURVEY IN FILDES PENINSULA,REY JORGE ISLAND,ANTARCTICA

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The present paper summarizes a joint effort undertaken by the Instituto Geográfico Militar de Chile (IGM) and the Instituto Antártico Chileno (INACH) in order to obtain digital cartography of the Fildes Peninsula,Rey Jorge Island,Antarctica.This peninsula constitutes the prototype project area for the main IGM_INACH project N° 153 “Cartographic Survey and Geographic Information System of the South Shetlands Islands" The Digital Cartography was implemented at the 1∶5 000 scale,using geodetic GPS control points referenced to ITRF 92 and WGS 84 Data.The UTM Projection was used.All products were produced in compliance with the cartographic standards of the IGM. This cartography was designed in order to satisfy the requirements of a Geographic Information System developed by INACH.This geo_referenced database incorporates a variety of thematic information,enabling it to support scientific investigations,environmental and multi_disciplinary studies,and other applications. As a result of this project the Instituto Geográfico Militar de Chile produced a map at 1∶5 000 scale in digital format,and also a 1∶10 000 topographic map,in paper format,with two editions: first edition of two charts and a second edition with one chart covering the whole project area. Chile and other countries have a number of important permanent activities in this area. These maps are designed to support several and diverse geo_spatial studies related to these activities.

  11. Ecosystem evolution of seal colony and the influencing factors in the 20th century on Fildes Peninsula, West Antarctica

    Institute of Scientific and Technical Information of China (English)

    Jing Huang; Liguang Sun; Xinming Wang; Yuhong Wang; Tao Huang

    2011-01-01

    As the topmost predator in Antarctica,the seal is a unique indicator of Antarctic environment and climate changes.In this study,we collected a sediment core from the Fildes Peninsula of West Antarctica,and used cholesterol,cholestanol,epicoprostanol,coprostanol,and seal hair numbers as the proxy indicators of seal population size and phytol as of general vegetation,and we reconstructed the 20th century history of variation of the seal population and vegetation abundance on this island.The sealing industry in the early 20th century caused the dramatic decline of seal population,and the ban of seal hunting since the 1960s led to its recovery of seal population.The seal population during the past century was primarily controlled by human activities and krill density.The reconstructed relation between seal population and vegetation abundance may offer new insights into Antarctic environment and ecology.

  12. A PRIMARY STUDY OF FOSSIL HILL FLORA FROM FILDES PENINSULA OF KING GEORGE ISLAND, ANTARCTICA

    Institute of Scientific and Technical Information of China (English)

    1990-01-01

    The fossil plants studied in this paper were collected by the Chinese Antarctic Expeditions (1986—1987 and 1987—1988) from the locality Fossil Hill on the Fildes Peninsula southwest of the King George Island of the South Shetland Islands.

  13. Ecological differences of south polar skua populations from Fildes Peninsula of King George Island and eastern Larsemann Hills,Antarctica

    Institute of Scientific and Technical Information of China (English)

    Wang Zipan; Hans-Ulrich Peter

    2004-01-01

    A study has been done on the comparison of nesting and feeding behavior, population variances as well as breeding success between two populations of south polar skua (Catharacta maccormicki) from near Great Wall station on Fildes Peninsula and near Zhongshan station in Eastern Larsemann Hills, Antarctica. There are evident differences in their population ecology. The foraging habit is much related to regional ecosystem and food resources near their territorial area. Dependence on human food waste influences skua's diet,which considerably affects their behavior even population variation in both areas. The skuas in Zhongshan Station,could shorten and/or regulate the timing for their egg laying and hatching, and take precedence of one chick brooding, for keeping their breeding success, and subsequent species continuation.

  14. Environmental monitoring and management proposals for the Fildes Region, King George Island, Antarctica

    Directory of Open Access Journals (Sweden)

    Christina Braun

    2012-05-01

    Full Text Available The Antarctic terrestrial environment is under increasing pressure from human activities. The Fildes Region is characterized by high biodiversity, but is also a major logistic centre for the northern Antarctic Peninsula. Different interests, from scientific research, nature conservation, protection of geological and historical values, station operations, transport logistics and tourism, regularly overlap in space and time. This has led to increasing conflict among the multiple uses of the region and breaches of the legal requirements for environmental protection that apply in the area. The aim of this study was to assess the impacts of human activities in the Fildes Region by monitoring the distribution of bird and seal breeding sites and recording human activities and their associated environmental impacts. Data from an initial monitoring period 2003–06 were compared with data from 2008–10. We observed similar or increased levels of air, land and ship traffic, but fewer violations of overflight limits near Antarctic Specially Protected Area No. 150 Ardley Island. Open waste dumping and oil contamination are still major environmental impacts. Scientific and outdoor leisure activities undertaken by station personnel are more frequent than tourist activities and are likely to have a commensurate level of environmental impact. Despite the initial success of some existing management measures, it is essential that scientific and environmental values continue to be safeguarded, otherwise environmental impacts will increase and the habitat will be further degraded. We argue that the Fildes Region should be considered for designation as an Antarctic Specially Managed Area, a measure that has proven effective for environmental management of vulnerable areas of the Antarctic.

  15. Diversity and structure of soil bacterial communities in the Fildes Region (maritime Antarctica as revealed by 454 pyrosequencing

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    Neng Fei eWang

    2015-10-01

    Full Text Available This study assessed the diversity and composition of bacterial communities in four different soils (human-, penguin-, seal-colony impacted soils and pristine soil in the Fildes Region (King George Island, Antarctica using 454 pyrosequencing with bacterial-specific primers targeting the 16S rRNA gene. Proteobacteria, Actinobacteria, Acidobacteria, and Verrucomicrobia were abundant phyla in almost all the soil samples. The four types of soils were significantly different in geochemical properties and bacterial community structure. Thermotogae, Cyanobacteria, Fibrobacteres, Deinococcus-Thermus, and Chlorobi obviously varied in their abundance among the 4 soil types. Considering all the samples together, members of the genera Gaiella, Chloracidobacterium, Nitrospira, Polaromonas, Gemmatimonas, Sphingomonas and Chthoniobacter were found to predominate, whereas members of the genera Chamaesiphon, Herbaspirillum, Hirschia, Nevskia, Nitrosococcus, Rhodococcus, Rhodomicrobium, and Xanthomonas varied obviously in their abundance among the four soil types. Distance-based redundancy analysis revealed that pH (p < 0.01, phosphate phosphorus (p < 0.01, organic carbon (p < 0.05, and organic nitrogen (p < 0.05 were the most significant factors that correlated with the community distribution of soil bacteria. To our knowledge, this is the first study to explore the soil bacterial communities in human-, penguin-, and seal- colony impacted soils from ice-free areas in maritime Antarctica using high-throughput pyrosequencing.

  16. Diversity and cold adaptation of culturable endophytic fungi from bryophytes in the Fildes Region, King George Island, maritime Antarctica.

    Science.gov (United States)

    Zhang, Tao; Zhang, Yu-Qin; Liu, Hong-Yu; Wei, Yu-Zhen; Li, Hai-Long; Su, Jing; Zhao, Li-Xun; Yu, Li-Yan

    2013-04-01

    Endophytic fungi associated with three bryophyte species in the Fildes Region, King George Island, maritime Antarctica, that is, the liverwort Barbilophozia hatcheri, the mosses Chorisodontium aciphyllum and Sanionia uncinata, were studied by culture-dependent method. A total of 128 endophytic fungi were isolated from 1329 tissue segments of 14 samples. The colonization rate of endophytic fungi in three bryophytes species were 12.3%, 12.1%, and 8.7%, respectively. These isolates were identified to 21 taxa, with 15 Ascomycota, 5 Basidiomycota, and 1 unidentified fungus, based on morphological characteristics and sequence analyses of ITS region and D1/D2 domain. The dominant fungal endophyte was Hyaloscyphaceae sp. in B. hatcheri, Rhizoscyphus sp. in C. aciphyllum, and one unidentified fungus in S. uncinata; and their relative frequencies were 33.3%, 32.1%, and 80.0%, respectively. Furthermore, different Shannon-Weiner diversity indices (0.91-1.99) for endophytic fungi and low endophytic fungal composition similarities (0.19-0.40) were found in three bryophyte species. Growth temperature tests indicated that 21 taxa belong to psychrophiles (9), psychrotrophs (11), and mesophile (1). The results herein demonstrate that the Antarctic bryophytes are an interesting source of fungal endophytes and the endophytic fungal composition is different among the bryophyte species, and suggest that these fungal endophytes are adapted to cold stress in Antarctica.

  17. Tectonic evolution of Bransfield Strait, West Antarctica

    Science.gov (United States)

    Barker, Daniel Hugh Njal

    Bransfield Strait is a young (Rocas Verdes basin supports the contention that Bransfield Strait rifting is in a transitional stage between continental/arc rifting and organized sea-floor spreading, and that it is a useful modern analog for the Rocas Verdes basin. Furthermore, it suggests that detachment faulting may be a common feature of backarc basins. Recognition of low-angle detachment faulting and simple-shear extension is essential for estimating basin extension, and the amount of crustal shortening and thickening that may occur during inversion of a basin such as the Rocas Verdes basin.

  18. Per- and polyfluoroalkyl substances in snow, lake, surface runoff water and coastal seawater in Fildes Peninsula, King George Island, Antarctica.

    Science.gov (United States)

    Cai, Minghong; Yang, Haizhen; Xie, Zhiyong; Zhao, Zhen; Wang, Feng; Lu, Zhibo; Sturm, Renate; Ebinghaus, Ralf

    2012-03-30

    The multi-matrices samples from snow (n=4), lake water (n=4), surface runoff water (SRW) (n=1) and coastal seawater (n=10) were collected to investigate the spatial distribution and the composition profiles of per- and polyfluoroalkyl substances (PFASs) in Fildes Peninsula, King George Island, Antarctica in 2011. All samples were prepared by solid-phase extraction and analyzed by using high performance liquid chromatography/negative electrospray ionization-tandem mass spectrometry (HPLC/(-)ESI-MS/MS). 14 PFASs in snow, 12 PFASs in lake water, 9 PFASs in SRW and 13 PFASs in coastal seawater were quantified, including C(4), C(7), C(8), C(10) PFSAs, C(4)-C(9), C(11)-C(14), C(16) PFCAs, and FOSA. PFOA was detected in all samples with the highest concentration (15,096 pg/L) in coastal seawater indicating a possible influence of local sewage effluent. High concentration and mostly frequency of PFBA occurred in snow (up to 1112 pg/L), lake water (up to 2670 pg/L) and SRW (1431 pg/L) while detected in the range of method detection limited (MDL) in the coastal seawaters indicate that PFBA is mainly originated from atmospheric dust contamination and also affected by the degradation of their precursors. No geographical differences in PFOS concentrations (n=8, 18 ± 3 pg/L) were measured in all snow and lake water samples also suggests that PFOS could be originated from the degradation of their precursors which can transported by long-range atmospheric route, but in a very low level.

  19. New data on the Late Pleistocene and Holocene glacial, climate and relative sea-level changes at Fildes Peninsula, King George Island (South Shetlands Islands, West Antarctica)

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    Verkulich, Sergey; Pushina, Zina; Tatur, Andrej

    2010-05-01

    New data on the Late Pleistocene and Holocene glacial, climate and relative sea-level changes at Fildes Peninsula, King George Island (South Shetlands Islands, West Antarctica) Verkulich S. R. (Arctic and Antarctic Research Institute, St. Petersburg, Russia) Pushina Z.V. (Arctic and Antarctic Research Institute, St. Petersburg, Russia) Tatur A. (Department of Antarctic Biology, Polish Academy of Sciences, Warsaw, Poland) During the 2008-2009 austral summer, co-operative Russian - Polish paleogeographical investigations allowed to refine the understanding of the past environmental events at Fildes Peninsula, King George Island. Old marine deposits (ca. 30000 yrs BP) with shells, whale bones and marine algae in situ were found in the western coastal and northern inland territories at the altitudes of 20-40 m a.s.l. that evidences the covering of considerable part of the peninsula by relatively warm sea waters before the Last Glacial Maximum. Quite good preservation of these deposits supposes relatively small thickness and weak erosional potential of ice masses overlying the area during the LGM. The early Holocene phase of the peninsula deglaciation was caused by both climate warming and marine transgression, which left the deposits with fossil flora and fauna at heights up to 15 m a.s.l. (maximum rise of the relative sea-level 7000-8000 yrs BP). During the middle Holocene, glacier contraction in the area continued (on the whole) due to mainly favorable climatic conditions. The presence of marine and terrestrial deposit blocks (with shells, algae, mosses) in moraine ridges on the surface of Collins Ice Cap signifies that this glacier could vanish from the peninsula during climate optimum (ca. 4000-3000 yrs BP). The processes of new formation and growth of the ice cap started probably ca. 2000 yrs BP; within the last 1000 years the limited advance of the glacier occurred (likely corresponding to the Little Ice Age), and was replaced then by modern process of its decay.

  20. Occurrence, bioaccumulation and long-range transport of short-chain chlorinated paraffins on the Fildes Peninsula at King George Island, Antarctica.

    Science.gov (United States)

    Li, Huijuan; Fu, Jianjie; Zhang, Aiqian; Zhang, Qinghua; Wang, Yawei

    2016-09-01

    As a candidate persistent organic pollutant of the Stockholm Convention, short-chain chlorinated paraffins (SCCPs) have recently received particular attention. In this study, we investigated, for the first time, the concentrations of SCCPs in biota samples collected from the Fildes Peninsula at King George Island and Ardley Island, Antarctica. The concentrations of SCCPs ranged from 3.5 to 256.6ng/g (dry weight, dw), with a mean of 76.6±61.8ng/g dw, which was lower than those detected in mid- and low-latitude regions. The long-range transport behaviour of SCCPs was confirmed by both the detection of SCCPs in Antarctic remote areas and their special congener profiles. Short carbon chain (C10) congeners predominated in the Antarctic samples, which accounted for 56.1% of the total SCCP contamination. Such enrichment of C10 congeners indicated the high potential for the long-range transport of shorter chain congeners. In addition, SCCPs tended to be enriched in the species with high lipid contents. The biomagnification potential of SCCPs was found between Archeogastropoda (Agas) and Neogastropoda (Ngas), and the biomagnification factors of shorter chain congeners of SCCPs were higher than that of the longer chain ones. Considering that the endemic species in polar regions may be sensitive and vulnerable to the adverse effects of environmental contaminants, more attention should be paid on the bioaccumulation and toxicological risks of SCCPs in polar environments.

  1. Summertime Surface N2O Concentration Observed on Fildes Peninsula Antarctica:Correlation with Total Atmospheric O3 and Solar Activity

    Institute of Scientific and Technical Information of China (English)

    朱仁斌; 孙立广; 尹雪斌; 刘晓东; 邢光熹

    2004-01-01

    Three-year summertime surface atmospheric N2O concentrations were observed for the first time on the Fildes Peninsula, maritime Antarctica, and the relationships among the N2O concentration, total atmospheric O3 amount, and sunspot number were analyzed. Solar activity had an important effect on surface N2O concentration and total O3 amount, and increases of sunspot number were followed by decreases in the N2O concentration and total O3 amount. A corresponding relationship exists between the N2O concentration and total atmospheric O3, and ozone destruction was preceded by N2O reduction.We propose that the extended solar activity in the Antarctic summer reduces the stratospheric N2O by converting it into NOx, increases the diffusion of N2O from the troposphere to the stratosphere, decreases the surface atmospheric N2O, and depletes O3 via the chemical reaction between O3 and NOx. Our observation results are consistent with the theory of solar activity regarding the formation of the Antarctic O3 hole.

  2. Up, Down, and All Around: Scale-Dependent Spatial Variation in Rocky-Shore Communities of Fildes Peninsula, King George Island, Antarctica

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    Valdivia, Nelson; Díaz, María J.; Holtheuer, Jorge; Garrido, Ignacio; Huovinen, Pirjo; Gómez, Iván

    2014-01-01

    Understanding the variation of biodiversity along environmental gradients and multiple spatial scales is relevant for theoretical and management purposes. Hereby, we analysed the spatial variability in diversity and structure of intertidal and subtidal macrobenthic Antarctic communities along vertical environmental stress gradients and across multiple horizontal spatial scales. Since biotic interactions and local topographic features are likely major factors for coastal assemblages, we tested the hypothesis that fine-scale processes influence the effects of the vertical environmental stress gradients on the macrobenthic diversity and structure. We used nested sampling designs in the intertidal and subtidal habitats, including horizontal spatial scales ranging from few centimetres to 1000s of metres along the rocky shore of Fildes Peninsula, King George Island. In both intertidal and subtidal habitats, univariate and multivariate analyses showed a marked vertical zonation in taxon richness and community structure. These patterns depended on the horizontal spatial scale of observation, as all analyses showed a significant interaction between height (or depth) and the finer spatial scale analysed. Variance and pseudo-variance components supported our prediction for taxon richness, community structure, and the abundance of dominant species such as the filamentous green alga Urospora penicilliformis (intertidal), the herbivore Nacella concinna (intertidal), the large kelp-like Himantothallus grandifolius (subtidal), and the red crustose red alga Lithothamnion spp. (subtidal). We suggest that in coastal ecosystems strongly governed by physical factors, fine-scale processes (e.g. biotic interactions and refugia availability) are still relevant for the structuring and maintenance of the local communities. The spatial patterns found in this study serve as a necessary benchmark to understand the dynamics and adaptation of natural assemblages in response to observed and

  3. Up, down, and all around: scale-dependent spatial variation in rocky-shore communities of Fildes Peninsula, King George Island, Antarctica.

    Directory of Open Access Journals (Sweden)

    Nelson Valdivia

    Full Text Available Understanding the variation of biodiversity along environmental gradients and multiple spatial scales is relevant for theoretical and management purposes. Hereby, we analysed the spatial variability in diversity and structure of intertidal and subtidal macrobenthic Antarctic communities along vertical environmental stress gradients and across multiple horizontal spatial scales. Since biotic interactions and local topographic features are likely major factors for coastal assemblages, we tested the hypothesis that fine-scale processes influence the effects of the vertical environmental stress gradients on the macrobenthic diversity and structure. We used nested sampling designs in the intertidal and subtidal habitats, including horizontal spatial scales ranging from few centimetres to 1000s of metres along the rocky shore of Fildes Peninsula, King George Island. In both intertidal and subtidal habitats, univariate and multivariate analyses showed a marked vertical zonation in taxon richness and community structure. These patterns depended on the horizontal spatial scale of observation, as all analyses showed a significant interaction between height (or depth and the finer spatial scale analysed. Variance and pseudo-variance components supported our prediction for taxon richness, community structure, and the abundance of dominant species such as the filamentous green alga Urospora penicilliformis (intertidal, the herbivore Nacella concinna (intertidal, the large kelp-like Himantothallus grandifolius (subtidal, and the red crustose red alga Lithothamnion spp. (subtidal. We suggest that in coastal ecosystems strongly governed by physical factors, fine-scale processes (e.g. biotic interactions and refugia availability are still relevant for the structuring and maintenance of the local communities. The spatial patterns found in this study serve as a necessary benchmark to understand the dynamics and adaptation of natural assemblages in response to

  4. Up, down, and all around: scale-dependent spatial variation in rocky-shore communities of Fildes Peninsula, King George Island, Antarctica.

    Science.gov (United States)

    Valdivia, Nelson; Díaz, María J; Holtheuer, Jorge; Garrido, Ignacio; Huovinen, Pirjo; Gómez, Iván

    2014-01-01

    Understanding the variation of biodiversity along environmental gradients and multiple spatial scales is relevant for theoretical and management purposes. Hereby, we analysed the spatial variability in diversity and structure of intertidal and subtidal macrobenthic Antarctic communities along vertical environmental stress gradients and across multiple horizontal spatial scales. Since biotic interactions and local topographic features are likely major factors for coastal assemblages, we tested the hypothesis that fine-scale processes influence the effects of the vertical environmental stress gradients on the macrobenthic diversity and structure. We used nested sampling designs in the intertidal and subtidal habitats, including horizontal spatial scales ranging from few centimetres to 1000s of metres along the rocky shore of Fildes Peninsula, King George Island. In both intertidal and subtidal habitats, univariate and multivariate analyses showed a marked vertical zonation in taxon richness and community structure. These patterns depended on the horizontal spatial scale of observation, as all analyses showed a significant interaction between height (or depth) and the finer spatial scale analysed. Variance and pseudo-variance components supported our prediction for taxon richness, community structure, and the abundance of dominant species such as the filamentous green alga Urospora penicilliformis (intertidal), the herbivore Nacella concinna (intertidal), the large kelp-like Himantothallus grandifolius (subtidal), and the red crustose red alga Lithothamnion spp. (subtidal). We suggest that in coastal ecosystems strongly governed by physical factors, fine-scale processes (e.g. biotic interactions and refugia availability) are still relevant for the structuring and maintenance of the local communities. The spatial patterns found in this study serve as a necessary benchmark to understand the dynamics and adaptation of natural assemblages in response to observed and

  5. Occurrence and gas/particle partitioning of short- and medium-chain chlorinated paraffins in the atmosphere of Fildes Peninsula of Antarctica

    Science.gov (United States)

    Ma, Xindong; Zhang, Haijun; Zhou, Hongqiang; Na, Guangshui; Wang, Zhen; Chen, Chen; Chen, Jingwen; Chen, Jiping

    2014-06-01

    Chlorinated paraffins (CPs) were measured in air samples at a remote air monitoring site established in Georgia King Island, Fildes Peninsula of Antarctica (Great Wall Station, China) to study the long-range atmospheric transport of these anthropogenic pollutants to the Antarctic. Gas- and particle-phase CPs were collected using polyurethane foam plugs (PUF) and glass fiber filters (GFF) respectively during summertime of 2012. The total atmospheric levels of SCCPs and MCCPs ranged from 9.6 to 20.8 pg m-3 (average: 14.9 pg m-3) and 3.7-5.2 pg m-3 (average: 4.5 pg m-3), respectively. C10 and C11 carbon chain homologues with Cl5 and Cl6 chlorine atoms predominated in SCCP formula groups both in gas- and particle-phase. Significant linear correlation was found between gas/particle partition coefficients (KP) and sub-cooled liquid vapor pressures (pL°) (R2 = 0.437, p < 0.01), as well as KP and octanol-air partition coefficients (KOA) (R2 = 0.442, p < 0.01). Absolute slope values of two regression models (0.31 and 0.39) were less than 0.6 indicating that the way of absorption into organic matter of aerosol played a more important role on atmospheric partitioning and transferring of CPs in remote Antarctic area. Both the Junge-Pankow model and the KOA-based model tended to underestimate the sorption of lower chlorinated CPs and overestimate the sorption of highly chlorinated CPs.

  6. Tidal and residual currents in the Bransfield Strait, Antarctica

    Directory of Open Access Journals (Sweden)

    O. López

    Full Text Available During the 1992-1993 oceanographic cruise of the Spanish R/V Hespérides, recording equipment was deployed in the Bransfield Strait. Six Aanderaa RCM7 current meters and three Aanderaa WLR7 tide gauges were successfully recovered after an operation period of 2.5 months. Relevant features of the time series obtained are presented and discussed in this paper. The emphasis is placed on the tidal character of the currents and the relative importance of tidal flow in the general hydrodynamics of the strait. For these purposes a dense grid of hydrographic stations, completed during the BIOANTAR 93 cruise, is used. Preliminary geostrophic calculations relative to a 400 m depth, yield current velocities of around 0.20 m s-1 in the study area, whereas the magnitude of tidal currents is seen to be 0.30-0.40 m s-1.

  7. 南极菲尔德斯半岛环境微生物含量估计%Estimation on Environmental Microbial Content in the Area of Fildes Peninsula,Antarctica

    Institute of Scientific and Technical Information of China (English)

    陈皓文; 袁峻峰; 曹俊杰; 张树荣

    2001-01-01

    A further exploration was made of the microbial content in thearea of Fildes Peninsula,Antarctica during the austral summers of 1993/1994. 206 samples of non-living materials collected from marine,land and air envinonments were tested.This paper recorded the content of different microbes including marine,terrigenous,intestinal bacteria;Cr-,Cd-,Hg-,Ag-,Fe-,negative ion detergent (LAS) -tolerant bacteria;acid-fast bacteria;petroleum hydrocarbon oxidizing bacteria;panomycetes,etc. These microbes were isolated from air,fog,rain,ice and snow,sea water,freshwater,including drinking water from water supply system;soil,sand,crashed stones from lakesides and beaches;lake sediments from diffrent depths and so on.A further understanding has been obtained of the microbiological condition in the ecological envinenments of the sruveyed area.%对1993~1994年南极夏季取自菲尔德斯半岛地区的空气、雾、雨、冰、雪、海、淡水、陆上、湖泊和海滨的土、砂、石、不同深度湖泊沉积物的206份样品的微生物,包括海洋性细菌、陆源性细菌、菌物(即真菌)、大肠埃希氏菌、耐铬、镉、汞、银、铁、阴离子洗涤剂(LAS)菌、耐酸菌及烃氧化菌等的含量做了分析,对该区域生态环境中的微生物状况有了更深的了解。

  8. Climate signals in Late Holocene sediments from Maxwell Bay and English Strait (South Shetland Islands, Antarctica)

    Science.gov (United States)

    Hass, H. Christian; Schröder, Simon; Kuhn, Gerhard

    2017-04-01

    Climate fluctuations of the past two millennia such as the Little Ice Age and the Medieval Warm Period are reported mainly from the Northern Hemisphere. Evidence from Antarctica is comparably sparse and reveals regional and temporal differences, which are particularly evident at the western and eastern sides of the Antarctic Peninsula. High-resolution coastal-marine sediment cores from the northernmost tip of the West Antarctic Peninsula reveal periods dominated by finer sediments between periods that lack the finer sediment component. In Maxwell Bay this fine sediment (grain size mode around 16 µm) has been traced back to sediment related to the occurrence of glacial meltwater. It was found in sheltered places and meltwater creeks of Potter Cove, a small tributary fjord to Maxwell Bay. In the sediment core this sediment occurs predominantly between 600 and 1250 AD (Medieval Warm Period) whereas it is only sparsely affecting the record between 1450 and 1900 AD (Little Ice Age). The temporal pattern is very similar to global-temperature reconstructions and even resembles temperature reconstructions from the Northern Hemisphere. To avoid local effects that may occur in Maxwell Bay more sediment cores were taken from bays and straits further south of King George Island during Cruise PS97 of RV "Polarstern" in 2016. A core from English Strait reveals completely different sedimentary conditions with no detectable meltwater signal (16 µm). However, the mean grain size record resembles that of the cores from Maxwell Bay. The lack of a clear-cut meltwater sediment class as it occurs further north is likely the result of a much smaller hinterland (Greenwich and Robert islands) when compared to Maxwell Bay between Nelson Island and the much bigger King George Island where glaciers and ice sheets discharge large quantities of very turbid meltwater directly into the bay. It is concluded that during the warmer climate periods a large amount of meltwater was released along the

  9. Reproductive biology of Perkinsiana antarctica (Kinberg (Polychaeta, Sabellidae in the Straits of Magellan (South America: Systematic and ecological implications

    Directory of Open Access Journals (Sweden)

    María Cristina Gambi

    1999-12-01

    Full Text Available Reproductive biology and larval development of the polychaete Perkinsiana Antarctica (Kinberg, 1867 (Sabellidae are described of a population sampled in October 1994 and March 1997 in the type locality of this species, the Straits of Magellan (Southern Chile. Perkinsiana antarctica is a simultaneous hermaphrodite. Eggs are present in the thorax and in the anterior part of the abdomen, while sperm cells occur in the posterior abdomen. Spermatids are grouped in tetrads; mature sperm cells present an oval nucleus (length of major axis about 3 µm and the acrosome is about 2.5 µm long with a conoid shape. Mature eggs have a mean diameter of 235 µm; embryos and larvae are incubated within the branchial crown of specimens exceeding 10 mm in length. Hatching larvae have a mean length of 420 µm, with 4 segments, each bearing two notochaeta; two ocular spots and a well-developed prototroch are present at the anterior end. Both number of embryos and larvae per individual showed a relatively high range of variation (embryos from 54 to 374, mean=173; larvae from 18 to 222, mean=101. The features of reproductive biology in P. antarctica do not seem to be related to the size of the species itself, as P. antarctica represents one of the largest-sized sabellids that are brooding eggs, and producing a relatively high number of offspring. These reproductive and developmental traits seem more related to the colonization of harsh and selective habitats, such as the intertidal and shallow subtidal of the Subantarctic areas. Comparisons with the reproductive biology of other species of Perkinsiana demonstrate a high degree of variability within the genus regarding reproduction and the apparent lack of synapomorphies.

  10. Multidecadal freshening and lightening in the deep waters of the Bransfield Strait, Antarctica

    Science.gov (United States)

    Dotto, Tiago S.; Kerr, Rodrigo; Mata, Mauricio M.; Garcia, Carlos A. E.

    2016-06-01

    The deep waters of the Bransfield Strait receive considerable amounts of water from the Weddell Sea continental shelf. The restricted connections to the surrounding ocean and relatively easier access makes the Bransfield Strait an important proxy region for monitoring changes in the dense Weddell Sea shelf water masses, which are an important precursor of Antarctic Bottom Water (AABW). Long-term hydrographic data from the period 1960s-2010s showed freshening and lightening of the deep water masses of the Bransfield Strait, which was likely caused by large freshwater inputs originating from the western shelf of the Weddell Sea. The rates of freshening and lightening were -0.0010 ± 0.0005 yr-1 and -0.0016 ± 0.0014 kg m-3 yr-1 for the central basin, respectively, and -0.0010 ± 0.0006 yr-1 and -0.0029 ± 0.0013 kg m-3 yr-1 for the eastern basin, respectively. The deep waters showed a high degree of interannual thermohaline variability, which appeared to be caused by changes in the proportions of source water mass mixing between the years. Statistically significant negative correlations between salinity/neutral density fields and the Southern Annular Mode (SAM) were observed (-0.56 and -0.62 for the central basin, respectively, and -0.58 and -0.68 for the eastern basin, respectively) between 1980 and 2014. During SAM positive phases, communication between the Weddell Sea and the Bransfield Strait is reduced, which leads to less saline and lighter water masses in the Bransfield Strait; however, the opposite trends are observed during SAM negative phases.

  11. Antarctica

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    ANYONEwhohasbeentoAntarctica,asIhave,willviewplanetearthfromanewangle.Whenyoutravel10,000kilometers,walkoutontothevastpolarcontinentandbreatheinitscrystallineair,aheightenedsenseoflivingonaglobe,ofbelongingtoalargeruniverse,willtakerootinyourmind.AnU...

  12. Distribution and characteristic of PAHs in snow of Fildes Peninsula

    Institute of Scientific and Technical Information of China (English)

    Guangshui Na; Chunyang Liu; Zhen Wang; Linke Ge; Xindong Ma; Ziwei Yao

    2011-01-01

    Polycyclic aromatic hydrocarbons (PAHs) investigation in different matrices has been reported largely,whereas reports on snow samples were limited.Snow,as the main matrix in the polar region,has an important study meaning.PAHs in snow samples were analyzed to investigate the distribution and contamination status of them in the Antarctic,as well as to provide some references for global migration of PAHs.Snow samples collected in Fildes Peninsula were enriched and separated by solid-phase membrane disks and eluted by methylene dichloride,then quantified by gas chromatography/mass spectrometry.All types of PAHs were detected except for Benzo(a)pyrene.Principal component analysis method was applied to characterize them.Three factors (Naphthalene,Fluorene and Pbenanthrene) accounted for 60.57%,21.61% and 9.80%,respectively.The results showed that the major PAHs sources maybe the atmospheric transportation,and the combustion of fuel in Fildes Peninsula.The comparison of concentration and types of PAHs between accumulated snow and fresh snow showed that the main compound concentrations in accumulated snow samples were higher than those in fresh ones.The risk assessment indicated that the amount of PAHs in the snow samples would not lead to ecological risk.

  13. Chinstrap penguin foraging area associated with a seamount in Bransfield Strait, Antarctica

    Science.gov (United States)

    Kokubun, Nobuo; Lee, Won Young; Kim, Jeong-Hoon; Takahashi, Akinori

    2015-12-01

    Identifying marine features that support high foraging performance of predators is useful to determine areas of ecological importance. This study aimed to identify marine features that are important for foraging of chinstrap penguins (Pygoscelis antarcticus), an abundant upper-trophic level predator in the Antarctic Peninsula region. We investigated the foraging locations of penguins breeding on King George Island using GPS-depth loggers. Tracking data from 18 birds (4232 dives), 11 birds (2095 dives), and 19 birds (3947 dives) were obtained in 2007, 2010, and 2015, respectively. In all three years, penguins frequently visited an area near a seamount (Orca Seamount) in Bransfield Strait. The percentage of dives (27.8% in 2007, 36.1% in 2010, and 19.1% in 2015) and depth wiggles (27.1% in 2007, 37.2% in 2010, and 22.3% in 2015) performed in this area was higher than that expected from the size of the area and distance from the colony (8.4% for 2007, 14.7% for 2010, and 6.3% for 2015). Stomach content analysis showed that the penguins fed mainly on Antarctic krill. These results suggest that the seamount provided a favorable foraging area for breeding chinstrap penguins, with high availability of Antarctic krill, possibly related to local upwelling.

  14. 南极菲尔德斯半岛海鸟与种群分布%SPECIES AND DISTRIBUTION OF THE BIRDS ON FILDES PENINSULA, KING GEORGE ISLAND, ANTARCTICA

    Institute of Scientific and Technical Information of China (English)

    王自磐; Hans Urlich Peter; Simone Pfeiffer

    2004-01-01

    2000/2001-2002/2003南极夏季期间,对中国南极长城站所在地乔治王岛菲尔德斯半岛及邻近区海鸟群落组成与种群分布特征进行了观测研究.本文报道了对该地区三次考察期间记录的海鸟共11科25种.其中,有繁殖活动的海鸟12种,优势种有白眉企鹅(Pygoscelis papua)和黄蹼洋海燕(Oceanites oceanicus),常见种有纹颊企鹅(Pygoscelis antarctica)、巨鹱(Macronectes giganteus)、花斑鹱(Daption capenis)、南极燕鸥(Sterna vittata) 和灰贼鸥(Catharacta antarctica)等.

  15. Backarc basin evolution and cordilleran orogenesis: Insights from new ocean-bottom seismograph refraction profiling in Bransfield Strait, Antarctica

    Science.gov (United States)

    Barker, Daniel H. N.; Christeson, Gail L.; Austin, James A., Jr.; Dalziel, Ian W. D.

    2003-02-01

    Bransfield Strait, a backarc basin off the northwestern Antarctic Peninsula, is a modern analog for Cretaceous basins inverted in the compressional tectonic regime that initiated the Andean Cordillera. Eight new refraction ocean-bottom seismograph profiles in the strait demonstrate that crustal thickness in the deep central basin increases from northeast to southwest, from ˜10 km to ˜14 16 km. This confirms multichannel seismic interpretation of upper crustal structures suggesting that the Bransfield basin is opening by northeast to southwest rift propagation within arc crust of the Antarctic Peninsula, a process also recorded in the obducted Cretaceous Rocas Verdes basin of the southernmost Andes. Thinning is most prominent along the axis of the strait, where the crust is ˜9 11 km thick. In contrast, thicknesses beneath the Antarctic Peninsula margin and the inactive South Shetland Islands pedestal are ˜18 km and ˜24 km, respectively. Seismic velocities and thicknesses suggest that new oceanic crust is not yet being generated. Extension is focused along the northwest margin, imparting the physiographic asymmetry to the strait. Comparing the Bransfield basin with the inverted Rocas Verdes basin and intraoceanic counterparts in the western Pacific suggests that rift propagation and trench-side focusing of extension may be fundamental features of young backarc basins. Resultant asymmetry may facilitate observed obduction of backarc basin floor and arc rocks onto continental margins during compressional orogenesis.

  16. Phylogenetic analysis and in vitro culture of mosses from the Antarctic Fildes Peninsula

    Institute of Scientific and Technical Information of China (English)

    LIU Shenghao; ZHANG Zhaohui; WANG Nengfei; CONG Bailin; ZHANG Pengying; LIN Xuezheng; HUANG Xiaohang

    2014-01-01

    Molecular genetic techniques have proven very useful for initial analysis of the extent of genetic variation and dispersal in several Antarctic moss species. In the present study, the small subunit ribosomal RNA (SSU rDNA) and internal transcribed spacers of the nuclear ribosomal DNA (ITS rDNA) were sequenced in nine individuals of different mosses from the Fildes Peninsula of Antarctica. Sequence alignment showed that the extreme environment tended to increase the genetic diversity of Antarctic mosses. In addition, in our phylogenetic analysis, one previously unidentiifed Antarctic moss species was characterized by comparison with SSU and ITS rDNA sequences of known moss species. Moreover, the optimal culture medium and conditions for surface explant sterilization and protonemata induction in tissue culture of Pohlia nutans were investigated. The successful establishment of a tissue culture protocol together with the phylogenetic analysis of Antarctic mosses will provide technological support to establish an effective resource regeneration method for discovering new functional genes and gaining novel insights into the mechanisms of stress acclimation.

  17. STRAIT REVIEW

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Relations across the Taiwan Strait got off the ground last year with direct flights between the mainland and Taipei, though interaction at an official level remained turbulent. The cross-strait relationship, which continues to be an unrelenting focus of government attention, has a complicated background and unclear future, a situation echoed in recent Chinese media reports on topics relating to Taiwan. While seemingly innocuous in subject matter-charter flights, cuddly pandas- the back-story to the headl...

  18. Strait Stance

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Despite rebukes against pro-independence Taiwan leader Chen Shui-bian's move to disrupt peace and stability across the Taiwan Strait, the mainland remains active in pushing forward links with the island. Sun Shengliang, a research fellow at the Institute of Taiwan Studies under the Chinese Academy of Social Sciences, analyzes the mainland's stance and efforts in cross-strait relations. Following are excerpts of his article carried in the People's Daily Overseas Edition:

  19. Seasonal variations of total {sup 234}Th and dissolved {sup 238}U concentration activities in surface water of Bransfield Strait, Antarctica, from March to October 2011

    Energy Technology Data Exchange (ETDEWEB)

    Lapa, Flavia V.; Oliveira, Joselene de; Costa, Alice M.R., E-mail: fvlapa@ipen.br, E-mail: jolivei@ipen.br, E-mail: lice_mrc@hotmail.com [Instituto de Pesquisas Energeticas e Nucleares (IPEN-CNEN/SP), Sao Paulo, SP (Brazil). Laboratorio de Radiometria Ambiental; Braga, Elisabete S., E-mail: edsbraga@usp.br [Universidade de Sao Paulo (USP), Sao Paulo, SP (Brazil). Inst. Oceanografico. Lab. de Nutrientes, Micronutrientes e Tracos nos Oceanos

    2013-07-01

    In this study the naturally occurring radionuclides {sup 234}Th and {sup 238}U were used to investigate the magnitude of upper ocean particulate organic carbon export in Bransfield Strait, Southern Ocean. This region is the largest oceanic high-nitrate low-chlorophyll (HNLC) area in the world and is known to contribute to regulate of the atmospheric CO{sub 2} via the biological pump. Due to its different geochemical behavior in seawater, the resulting U/Th disequilibria can be easily used to constrain the transport rates of particles and reaction processes between solution and particulate phases. Sampling occurred during the summer (March and November) 2011. Total {sup 234}Th activities in surface seawater samples ranged from 1.3 to 3.7 dpm L{sup -1} (station EB 011) during March/11 campaign, while in October/11 total {sup 234}Th activity concentrations varied from 1.4 to 2.9 dpm L{sup -1}. Highest total {sup 234}Th activities were found late in the austral summer season. Activity concentrations of dissolved {sup 238}U in surface seawater varied from 2.1 to 2.4 dpm L{sup -1}. Taking into account all sampling stations established in March and October/11 the relative variability of total {sup 234}Th distribution was 22%. (author)

  20. 南极Gerlache海峡海鸟的取食集群及食性%Feeding aggregation and diets of seabirds at Gerlache Strait, Antarctica

    Institute of Scientific and Technical Information of China (English)

    Marco FAVERO; Néstor Bubén CORIA

    2007-01-01

    Foraging associations between flying seabirds and penguins were studied from December 1997 to February 1998 at Cierva Point, Antarctic Peninsula. Observations were complemented with dietary information on the main species observed in aggregations. An average of 35.6±37.0 flying birds per aggregation was observed, almost all of them associated to chinstrap penguin Pygoscelis antarctica groups. The most common species were kelp gulls Larus dominicanus, South Polar skuas Catharacta maccormicki, pintado petrels Daption capensis and southern giant petrels Macronectes giganteus. The number of associations observed per sampling unit decreased as the season progressed, in some species accordingly with particular stage of their phenology. Antarctic krill Euphausia superba was particularly important in the diet of most abundant flying bird species in assemblages. The overlap index for krill sizes consumed give highest values in the comparisons between kelp gulls and chinstrap penguins. The foraging behaviour of flying birds suggested that prey was available near the surface for short time periods, likely facilitated by movements of krill avoiding penguin predation[Acta Zoologica Sinica 53(3):425-430,2007].%1997年12月至1998年2月,我们对南极半岛席尔瓦角善于飞翔海鸟与企鹅的取食关联性进行了研究,同时调查了取食集团中主要鸟种的食性.发现每个取食集团中有35.6-37.0只善于飞翔的海鸟,其中几乎都有纹颊企鹅群 (Pygoscelis antarctica),黑背鸥(Larus dominicanus)、灰贼鸥(Catharacta maccormicki)、花斑鹱(Daption capensis)和巨鹱(Macronectes giganteus)是各集团中最常见的鸟类.各取样单元内有相关性的种数随季节变化而减少,一些种类的减少与特定的物候期有关.南极磷虾(Euphausia superba)是绝大部分飞翔海鸟的主要食物,研究发现黑背鸥与纹颊企鹅所捕食的南极磷虾的大小最为接近.飞翔海鸟的觅食行为表明:在海面上短时停

  1. AVALIAÇÃO DOS TEORES DE Pb, Cd, Sn, Co, Hg, Mo E As EM SOLOS DA PENÍNSULA FILDES - ANTÁRTICA

    Directory of Open Access Journals (Sweden)

    Bruna M. Dalfior

    Full Text Available Antarctic Continent is one of the few places that has not been explored at all, but studies show that this place is suffering interference by human activities. Therefore, monitoring of this region becomes very important. After optimization and verification of the methodology, the concentrations of Pb, Cd, Sn, Co, Hg, Mo and As in soil samples collected in the Fildes Peninsula, King George Island, Antarctica, were determined by ICP-MS. The ranges found (µg kg-1 were: for Pb 525.2-2314.1, for Cd 54.8-193.8, for Sn 54.8-193.8, for Co 2095.0-11094.1, for Hg < 2.4-54.6, for Mo 5.3-38.7 and for As 120.3-1297.1. In general, the presence of these elements can be attributed to different factors, such as natural composition of soil, melting process and transport of chemical elements caused by physical phenomena as sea and air currents, besides anthropic contamination. Using enrichment factor was possible suggest contribution by anthropic activities mainly for Co and As. Thus, it is important monitoring the elements levels constantly assisting in environmental protection.

  2. Paleomagnetism of King George Island, South Shetlands, Antarctica

    Science.gov (United States)

    Slotznick, S. P.; Kirschvink, J. L.; Raub, T. D.; Swanson-Hysell, N.; Edgar, L.

    2011-12-01

    During December of 2009 when the US R/V Lawrence M. Gould was iced out of the Antarctic Peninsula, we collected core and block samples from 17 different flows and dikes at three sampling areas on Weaver Peninsula and Fildes Peninsula, King George Island, South Shetland Islands, Antarctica. Two of the three sampling areas on Weaver Peninsula and Fildes Peninsula were near dikes with Ar-Ar ages of 54.6 ± 3.8 Ma and 57.4 ± 2.1 Ma respectively, close in age to the Paleocene Eocene Thermal Maximum (PETM) (Kraus 2005, Kraus et al. 2007). After removal of significant magnetically soft components by low-temperature cycling and weak AF demagnetization, the basaltic flows from the Weaver Peninsula preserve a dual-polarity characteristic remanence isolated by higher-field AF demagnetization with an in-situ magnetization of D = 166.3, I= 65.4 (n/N = 24/30, α95 = 6.31). This direction, prior to correction for bedding tilt, is indistinct from a plausible Cenozoic reversed polarity magnetization for the site, while correcting for bedding tilt results in anomalously shallow inclinations. This result implies a post-tilting thermochemical remagnetization origin for the characteristic remanence. Analyses of the baked contact, dikes, and conglomerate tests help constrain the age of this event in context of subsequent Cenozoic magmatism on King George Island. Rock magnetic and Kappabridge experiments show that the magnetic mineralogy of the samples is often dominated by magnetite, with titanomagnetite and hematite present in some flows. The results of this multi-site study of Weaver and Fildes Peninsulas add to a growing paleomagnetic database for volcanic rocks from King George Island (Valencio et al. 1979, Kraus et al. 2010, Watts et al. 1984, Nawrocki et al. 2010) and contribute to a better understanding of the complex tectonic and magmatic activity of the South Shetland Islands.

  3. Hello Antarctica

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    China has made 25 expeditions to the Antarctic over a quarter century Exactly 17,501.949 km-that’s the distance from Beijing to Changcheng (lit-erally meaning the Great Wall) Station,the first little piece of China on the continent of Antarctica. Twenty-five years ago, when the country was conceiving its first journey to the South Pole, that distance meant nothing

  4. Temporal evolution of natural radionuclides distributions {sup 238}U, {sup 234}Th, {sup 226}Ra, {sup 228}Ra, {sup 210}Pb and {sup 210}Po in the Bransfield strait, Antarctica peninsula; Evolucao temporal das distribuicoes dos radionuclideos naturais {sup 238}U, {sup 234}Th, {sup 226}Ra, {sup 228}Ra, {sup 210}Pb and {sup 210}Po no estreito de Bransfiel, peninsula Antartica

    Energy Technology Data Exchange (ETDEWEB)

    Lapa, Flavia Valverde

    2013-07-01

    Research on the distribution of natural radionuclides in Antarctica is rare and thus, there is great interest in to know their occurrence and factors related to its mobilization, transference and accumulation in this extremely fragile environment. Natural radionuclides have been used intensively as tracers in the ocean, helping to better understand processes as sinking and particle resuspension, water masses mixture and oceanic circulation. {sup 234}Th (t½ = 24.1 days) is a particle-reactive radionuclide produced continuously in seawater by the decay of its soluble precursor conservative with salinity {sup 238}U (t½ = 4.5 10{sup 9} years). Since {sup 234}Th presents relatively short half-life, it is used to quantify processes that occur in temporal scale varying from days to weeks. The disequilibrium {sup 234}Th/{sup 238}U in the surface ocean has been applied to estimate carbon fluxes exported via sinking material. The flux of particles biologically productive out of the euphotic zone in the Southern Ocean has special attention due to its importance in the control of CO{sub 2} atmospheric concentrations. The radionuclides {sup 210}Pb (t½ = 22.3 years) and {sup 210}Po (t½ = 138 days) are also particle-reactive. The disequilibrium {sup 210}Po/{sup 210}Pb has been used to estimate fluxes of particles exported in the ocean in the time scale of weeks. The long-lived Ra isotopes, {sup 226}Ra (t½ = 1,600 years) and {sup 228}Ra (t½ = 5.75 years) are soluble in seawater, presenting unique properties that make them excellent tracers of water masses. This research work had the aim to study the distributions of natural radionuclides {sup 238}U, {sup 234}Th, {sup 22}'6Ra, {sup 22}'8Ra, {sup 210}Pb and {sup 210}Po in the Bransfield Strait during 2 samplings carried out in the 2011 Austral Summer (OPERANTAR XXIX and XXX). (author)

  5. UAV Antarctica

    OpenAIRE

    Dahl, David; Stetler, Fredrik

    2014-01-01

    One of the biggest problems of our time is the global warming. A direct result of this phenomena is the melting of ice of the glaciers on the north and the south pole. As this continues, the melted ice will contribute to an increase of the sea level, and may cause enormous natural disasters. To be able to prevent this, it’s important to study its affects. This reports contains a concept study of a Unmanned Aerial Vehicle, a UAV, set on the coast of Antarctica by the Australian owned base Davi...

  6. Rock weathering Tendency at Different Stages of Soil—Forming Processes in Fildes Peninsula,Antarctic

    Institute of Scientific and Technical Information of China (English)

    CHENJIE; GONGZITONG

    1996-01-01

    From the view of energy state of material,this paper introduces a concept a concept of weathering potential in carrying out quantitative calculation of the relevant products at different stages of rock-weathering and primary soil-forming processes,elaborates respectively on weathering degree in the bio-weathering layer of rocks and during the formation of soil material and clay,and evaluats the further tendency of weathering in the above-mentioned stages.The authors have discovered that the scales of weathering potential of the materials increase successively in the three stages,which indicates that the products in the above-mentioned three stages must have undergone stronger and stronger weathering in the primitive forming process of soil in Fildes Peninsula,Antarctic.But,Because of relatively weak chemical weathering,it is reasonable that there are much more skeleton grains and little clay in priamry soils in this region.Meanwhile the authors have also verified that the weathering potential of crde rock determines to some extent decrease in the products' weathering potential in the different stages in primary soil-forming,thereby plays an important role in the genesis and development of the primary soil in the studied area.

  7. The Davis Strait

    DEFF Research Database (Denmark)

    The Bureau of Minerals and Petroleum (BMP) is planning for further exclusive licences for exploration and exploitation of hydrocarbons in the Greenland off shore areas of Davis Strait. To support the decision process BMP has asked DCE - Danish Centre for Environment and Energy and the Greenland...... with the existing licence blocks, the SEIA describes the physical and biological environment including protected areas and threatened species, contaminent levels, and natural resource use. This description of the existing situation then forms the basis for assessment of the potential impacts of oil activities...

  8. The Davis Strait

    DEFF Research Database (Denmark)

    The Bureau of Minerals and Petroleum (BMP) is planning for further exclusive licences for exploration and exploitation of hydrocarbons in the Greenland off shore areas of Davis Strait. To support the decision process BMP has asked DCE - Danish Centre for Environment and Energy and the Greenland...... with the existing licence blocks, the SEIA describes the physical and biological environment including protected areas and threatened species, contaminent levels, and natural resource use. This description of the existing situation then forms the basis for assessment of the potential impacts of oil activities....... If more licences are granted in the assessment area implementation of an environmental background study programme is planned to fi ll the data gaps that have been identifi ed and provide information required to support the environmental planning and regulation of the oil activities. The new information...

  9. Postglacial relative sea level change at Fildes Peninsula, King George Island (West Antarctic

    Directory of Open Access Journals (Sweden)

    K. V. Polishchuk

    2016-01-01

    Full Text Available Analysis and integration of data obtained in our field and laboratory investigations of 2008–2012 together with results of previous paleogeographic studies were conducted to reveal parameters and factors of the post-glacial changes in the relative sea-level on the Fildes Peninsula and the King George Island. Results of dating of organic material taken from cross-sections of Quaternary deposits, data on morphology of marine landforms as well as on bottom sediments in lakes were used to construct a curve of changes in the relative sea-level.Our research has shown that the rapid rise of relative sea level in the area (since the beginning of the Holocene decelerated about 8000 years BP, achieving its maximum about 7000 years BP. This was followed by the fall of relative sea-level (the land elevation by 18–20  m in total, and it was characterized by relatively high rate of fall during periods of 6000– 5000 years BP, 4000–2500 years BP, and during the last 1500 years; the rate decreased in 5000–4000 years BP and 2500– 1600 years BP. The changes in relative sea level in this region were determined by the following factors: the eustatic component of the global changes in sea-level and, possibly, oscillations in the global sea level of another nature; local parameters of the Last glacial maximum; a course of the Peninsula deglaciation; regional physical characteristics of the Earth's crust and the mantle substances; local tectonic processes, including the isostatic rebound. Since the beginning of the Holocene up to about 7000 years BP, the main contribution to changes of the relative sea-level in this area was made by the global eustatic factor. The subsequent fall of the relative sea-level (elevation of the Peninsula surface proceeded under condition of reduced role of the eustatic factor and predominance of other factors.

  10. Taiwan strait dispute

    Directory of Open Access Journals (Sweden)

    Kastrati Bilbil

    2015-12-01

    Full Text Available The end of the Cold War resulted in a diffusion of the level of threat worldwide and concluded the system of bipolarity in the world. Beside the European continent, where the rivalries were at the highest level, the consequences of the end of the Cold War were especially visible in North-East Asia. A decrease of military activities of Russia and China, and the retreat of the USA from the region, give way for improvement of political and economical relations between the countries of the region. The end of hostilities produced by the Cold War no doubt have relaxed relations between countries in the region and opened ways for a new more peaceful co-existence. However, this does not mean that the region is not vulnerable to some of the hot spots such as North Korea, Spratly Parcels and especially Taiwan Strait. The latter is considered to be the most dangerous potential Asian zone of crisis in the twenty-first century.

  11. Detection of integron integrase genes on King George Island, Antarctica

    Institute of Scientific and Technical Information of China (English)

    Vernica Antelo; Hctor Romero; Silvia Batista

    2015-01-01

    The presence and diversity of class 1 integrase gene (intI) sequences were evaluated by PCR using previously designed primers. Two clone libraries were constructed from DNA in sediment and microbial mat samples collected on Fildes Peninsula, King George Island, Antarctica.The libraries constructed from samples collected at Halfthree Point (HP) and Norma Cove (NC) contained 62 and 36 partial intI sequences, respectively. These sequences clustered into 10 different groups with <95% amino acid identity. Alignment of the deduced amino acid sequences with those from recognized integron-encoded integrases demonstrated the presence of highly conserved motifs characteristic of intI integrases. The HP library contained 42 nucleotide sequences identical to the class 1 intI gene found in a collection of trimethoprim-resistant (Tmpr) Antarctic Enterobacter sp. isolates, previously collected in the same area. These integrons, located on plasmids, had a genetic organization similar to that of pKOX105 from Klebsiella oxytoca. The 20 remaining HP and NC library sequences were similar to integrase sequences previously determined in a metagenomic analysis of environmental samples. We have demonstrated the presence of integron integrase genes in Antarctic sediment samples. About half these genes were very similar to the class 1 integrons found in human-associated microbiota, suggesting that they originated from human-dominated ecosystems. The remaining integrase genes were probably associated with endemic bacteria.

  12. Mineral resources of Antarctica

    Science.gov (United States)

    Compiled and edited by Wright, Nancy A.; Williams, Paul L.

    1974-01-01

    Although the existence of mineral deposits in Antarctica is highly probable, the chances of finding them are quite small. Minerals have been found there in great variety but only as occurrences. Manganese nodules, water (as ice), geothermal energy, coal, petroleum, and natural gas are potential resources that could perhaps be exploited in the future. On the basis of known mineral occurrences in Antarctica and relationships between geologic provinces of Antarctica and those of neighboring Gondwana continents, the best discovery probability for a base-metal deposit in any part of Antarctica is in the Andean orogen; it is estimated to be 0.075 (75 chances in 1,000).

  13. Bringing Antarctica Home

    Science.gov (United States)

    Constible, Juanita; Williams, Lauren; Faure, Jaime; Lee, Richard E., Jr.

    2012-01-01

    When one thinks of the amazing creatures of Antarctica, an insect probably does not come to mind. But this unlikely animal, and a scientific expedition to Antarctica, was the foundation for a learning event that created a community of learners spanning kindergarten through sixth grade and extended beyond the classroom. Miami University's Antarctic…

  14. Antarctica - Ross Ice Shelf

    Science.gov (United States)

    1990-01-01

    This color picture of Antarctica is one part of a mosaic of pictures covering the entire polar continent taken during the hours following Galileo's historic first encounter with its home planet. The view shows the Ross Ice Shelf to the right and its border with the sea. An occasional mountain can be seen poking through the ice near the McMurdo Station. It is late spring in Antarctica, so the sun never sets on the frigid, icy continent. This picture was taken about 6:20 p.m. PST on December 8, 1990. From top to bottom, the frame looks across about half of Antarctica.

  15. Composition of phytoplankton in the Bransfield Strait and Elephant Island during austral summer of 1999

    Directory of Open Access Journals (Sweden)

    Sonia Sánchez

    2014-06-01

    Full Text Available The authors inform about the composition and distribution of phytoplanktonic community between the first 75 m of depth in Bransfield Strait y around the Elephant island, during the ANTAR X expedition in the 1999 Austral Summer (22nd–29th January 1999. The higher cellular concentration (500 cel/mL was given by the autotrophic nanoplankton, with a high density mainly on the bay stations and down the first 25 m of depth. Among the most representative species we have Leucocryptos marina, Phaeocystis antarctica, the Monadas and the pennate diatoms.

  16. Living and Working in Antarctica.

    Science.gov (United States)

    Kemp, Noel

    This source book, designed for 11- to 14-year-old students, seeks to describe what life is like in Antarctica. In spite of extreme weather conditions, people go to Antarctica to work every summer. Some of them stay there during the winter as well. This book seeks to supply answers to such questions as: How do people get to Antarctica? Why do they…

  17. Indonesian Maritime Security Cooperation In the Malacca Straits

    Science.gov (United States)

    2015-06-01

    Straits compared to other littoral states since the majority of Indonesia’s trade is conducted through the Lombok and the Sunda Straits. He argues...Weight Tonnage (DWT) should not be allowed to pass through the Malacca Straits and should be re-routed through the Lombok -Makassar Straits.107

  18. Fossil nothofagaceous leaves from the Eocene of western Antarctica and their bearing on the origin, dispersal and systematics of Nothofagus

    Institute of Scientific and Technical Information of China (English)

    LI; HaoMin

    2007-01-01

    Fossil leaves resembling Nothofagaceae have been investigated from the Eocene of western Antarctica and a new form genus Nothofagofolia is proposed for these kinds of fossils. Some new specimens belonging to this form genus are described. They were collected from the Fossil Hill locality of Fildes Peninsula, King George Island, South Shetland Islands, western Antarctica. Two new species, two new combinations and an unnamed species are reported. A number of published Nothofagus leaf fossils from the same locality are discussed and revised. As a result of these studies of Nothofagus leaf morphology, we conclude that (1) Nothofagus probably originated in high latitudes of the Southern Hemisphere during the middle-late Late Cretaceous and diversified, dispersed gradually to the lower latitudes of the same hemisphere; (2) leaf morphological characters are significant for the systematics of the family Nothofagaceae, especially at the intrageneric level; and (3) extant species of Nothofagus known from southern temperate areas have more primitive leaf morphological characters and lower leaf ranks than those from tropical mountains as well as those of the Fagaceae and Betulaceae.

  19. A MILESTONE IN CROSS-STRAITS RELATIONS

    Institute of Scientific and Technical Information of China (English)

    DENG YUNGUANG; DING XING

    2010-01-01

    @@ Chongqing, the southwestern municipality that served as China's capital during World War Ⅱ, will be remembered again for hosting a landmark event in the Chinese history on June 29. On that day, Chen Yunlin,President of the mainland's Association for Relations Across the Taiwan Straits,and Chiang Pin-kung, Chairman of Taiwan's Straits Exchange Foundation,signed the long-awaited Economic Cooperation Framework Agreement (ECFA) in Chongqing, a move hailed by many as a milestone in cross-Straits relations.

  20. Antarctica: Discovery & Exploration.

    Science.gov (United States)

    Gascoigne, Toss; Collett, Peter

    An examination of Antarctica, from the first sightings to the heroic explorations of the late 18th and early 19th centuries to modern-day research, is presented in this book. Twelve chapters are as follows: (1) The search begins; (2) Whalers and sealers: bites and nibbles; (3) The new continent: first sight; (4) Wintering: the first party; (5)…

  1. Tectonics of Antarctica

    Science.gov (United States)

    Hamilton, W.

    1967-01-01

    Antarctica consists of large and wholly continental east Antarctica and smaller west Antarctica which would form large and small islands, even after isostatic rebound, if its ice cap were melted. Most of east Antarctica is a Precambrian Shield, in much of which charnockites are characteristic. The high Transantarctic Mountains, along the Ross and Weddell Seas, largely follow a geosyncline of Upper Precambrian sedimentary rocks that were deformed, metamorphosed and intruded by granitic rocks during Late Cambrian or Early Ordovician time. The rocks of the orogen were peneplained, then covered by thin and mostly continental Devonian-Jurassic sediments, which were intruded by Jurassic diabase sheets and overlain by plateau-forming tholeiites. Late Cenozoic doming and block-faulting have raised the present high mountains. Northeastern Victoria Land, the end of the Transantarctic Mountains south of New Zealand, preserves part of a Middle Paleozoic orogen. Clastic strata laid unconformably upon the Lower Paleozoic plutonic complex were metamorphosed at low grade, highly deformed and intruded by Late Devonian or Early Carboniferous granodiorites. The overlying Triassic continental sedimentary rocks have been broadly folded and normal-faulted. Interior west Antarctica is composed of miogeosynclinal clastic and subordinate carbonate rocks which span the Paleozoic Era and which were deformed, metamorphosed at generally low grade, and intruded by granitic rocks during Early Mesozoic time and possibly during other times also. Patterns of orogenic belts, if systematic, cannot yet be defined; but fragmentation and rotation of crustal blocks by oroclinal folding and strike-slip faulting can be suggested. The Ellsworth Mountains, for example, consist of Cambrian-Permian metasedimentary rocks that strike northward toward the noncorrelative and latitudinally striking Mesozoic terrane of the Antarctic Peninsula in one direction and southward toward that of the Lower Paleozoic: terrane

  2. On Flow Variability in the Bosphorus Strait

    Science.gov (United States)

    2011-08-27

    Atlantic Treaty Organization (NATO) Undersea Research Center ( NURC ) in collaboration with the Turkish Navy Office of Navigation, Hydrography, and...Oceanography deployed two mooring sections in the Bosphorus Strait (at the Black Sea and Sea of Marmara entrances) from the R/V Alliance (a NATO- NURC ...research vessel) as a part of TSS08 ( NURC project) and "Exchange Processes in Ocean Straits" (EPOS, NRL project) programs in September 2008 (Figure 1

  3. Application of natural Ra isotopes and {sup 234}Th as tracers of organic carbon export in Bransfield Strait, Antarctica; Aplicacao dos isotopos naturais de Ra e do Th-234 como tracadores do carbono organico exportado para o Estreito de Bransfield, Antartica

    Energy Technology Data Exchange (ETDEWEB)

    Vieira, Lucia Helena

    2011-07-01

    The Southern Ocean is the largest of several high-nutrient, low-chlorophyll (HNLC) regions in the world's oceans. This region plays a major role in regulating the global net transfer of carbon dioxide between the ocean and the atmosphere, in part because the annual photosynthetic uptake of CO{sub 2} by phytoplankton and resulting export of particulate organic carbon (POC) to the deep ocean. The element thorium has multiple radioisotopes that have emerged collectively as a powerful set of tracers for particle associated processes in the oceans. Of all the Th isotopes, {sup 234}Th (half-life 24.1 d) has been the focus of increasing attention and application in the past years. The production of {sup 234}Th from {sup 238}U, coupled with the conservative behavior of {sup 238}U in seawater, makes the source of {sup 234}Th easy to characterize. Moreover, the half-life of {sup 234}Th is sufficiently short to make it sensitive to the short-term (e.g. seasonal) changes that occur in the upper water column of the open ocean or in sediments or water column in coastal areas. Because of its very particle reactive behavior, {sup 234}Th is removed from a parcel of water in only two ways, through decay and through particle flux. Therefore, a steady-state 1D activity balance can be used to calculate its flux. Natural Ra isotopes have been also widely used in marine studies to trace water masses and to quantify mixing processes. This work presents results of a collaborative research on organic carbon fluxes distribution in the Bransfield Strait in order to evaluate its influence in the CO{sub 2} drawdown. Macro-nutrients, micro-nutrients and chlorophyll-a distributions were used to examine the pathway sources. Natural radium isotopes were applied as tracers to study the movement of shelf water, while {sup 234}Th was used as a tracer of particle flux in the upper ocean, since POC export via sinking particles is the primary mechanism of carbon sequestration in the Southern Ocean

  4. U.S. and Russia sign agreements to cooperate in Antarctica and Beringia

    Science.gov (United States)

    Showstack, Randy

    2012-09-01

    U.S. secretary of state Hillary Rodham Clinton and Russian foreign minister Sergey Lavrov signed a Memorandum of Understanding (MOU) for Cooperation in Antarctica and issued a Joint Statement on Pursuing a Transboundary Area of Shared Beringian Heritage, which is related to a segment of the Bering Strait, at an 8 September ceremony in Vladivostok, Russia. The Antarctica MOU strengthens cooperation and improves coordination of bilateral policies, science, logistics, search and rescue, training, and public outreach in Antarctica. “We are formally deepening our scientific cooperation in Antarctica, a continent with vast opportunities for research,” Clinton said. “Scientists from both our countries will work together to explore Antarctica's terrain, study the effects of climate change, and cooperate on a range of issues to better understand and protect our shared environment.” She added that U.S. and Russian officials and scientists will work together to enforce the 1959 Antarctic Treaty, including inspecting foreign facilities and looking for violations of the treaty and environmental commitments.

  5. Astronomy in Antarctica

    CERN Document Server

    Burton, Michael G

    2010-01-01

    Antarctica provides a unique environment for astronomy. The cold, dry and stable air found above the high plateau, as well as the pure ice below, offers new opportunities across the photon & particle spectrum. The summits of the plateau provide the best seeing conditions, the darkest skies and the most transparent atmosphere of any earth-based observing site. Astronomical activities are now underway at four plateau sites: the Amundsen-Scott South Pole Station, Concordia Station at Dome C, Kunlun Station at Dome A and Fuji Station at Dome F, in addition to long duration ballooning from the coastal station of McMurdo. Astronomy conducted includes optical, IR, THz & sub-mm, measurements of the CMBR, solar, as well as high energy astrophysics involving measurement of cosmic rays, gamma rays and neutrinos. Antarctica is also the richest source of meteorites on our planet. An extensive range of site testing measurements have been made over the high plateau. We summarise the facets of Antarctica that are dri...

  6. Informal STEM Education in Antarctica

    Science.gov (United States)

    Chell, K.

    2010-12-01

    Tourism in Antarctica has increased dramatically with tens of thousands of tourists visiting the White Continent each year. Tourism cruises to Antarctica offer a unique educational experience for lay people through informal science-technology-engineering-mathematics (STEM) education. Passengers attend numerous scientific lectures that cover topics such as the geology of Antarctica, plate tectonics, glaciology, and climate change. Furthermore, tourists experience the geology and glaciology first hand during shore excursions. Currently, the grand challenges facing our global society are closely connected to the Earth sciences. Issues such as energy, climate change, water security, and natural hazards, are consistently on the legislative docket of policymakers around the world. However, the majority of the world’s population is uninformed about the role Earth sciences play in their everyday lives. Tourism in Antarctica provides opportunities for informal STEM learning and, as a result, tourists leave with a better understanding and greater appreciation for both Antarctica and Earth sciences.

  7. Hovercraft experience in Antarctica

    Science.gov (United States)

    Cook, Harvey C.

    The Model 1500 TD air-cushion vehicle (ACV) has been modified for the extreme conditions encountered in Antarctic operations; these operations began in the 1988-1989 austral summer. Performance evaluations covering 300 hours of engine operations have been obtained which demonstrate the basic soundness of this ACV's design and construction, and its applicability to Antarctic operations, where it was able to reduce travel time and fuel consumption in excess of 40 percent. In addition, passenger comfort was increased manyfold over wheeled and tracked vehicles for comparable missions. The ACV is judged capable of solving many of the transportation problems experienced in Antarctica.

  8. Antarctica Day: An International Celebration

    Science.gov (United States)

    Pope, A.; Hambrook Berkman, J.; Berkman, P. A.

    2013-12-01

    For more than half a century, the 1959 Antarctic Treaty continues to shine as a rare beacon of international cooperation. To celebrate this milestone of peace in our civilization with hope and inspiration for future generations, Antarctica Day is celebrated each year on December 1st , the anniversary of the Antarctic Treaty signing. As an annual event - initiated by the Foundation for the Good Governance of International Spaces (www.internationalspaces.org/) in collaboration with the Association of Polar Early Carer Scientists (www.apecs.is) - Antarctica Day encourages participation from around the world. The Antarctic Treaty set aside 10% of the earth, 'forever to be used exclusively for peaceful purposes in the interest of mankind.' It was the first nuclear arms agreement and the first institution to govern all human activities in an international region beyond sovereign jurisdictions. In this spirit, Antarctica Day aims to: - Demonstrate how diverse nations can work together peacefully, using science as a global language of cooperation for decision making beyond national boundaries, - Provide strategies for students learning about Antarctica through art, science and history at all school levels, - Increase collaboration and communication between classrooms, communities, researchers and government officials around the world, and - Provide a focus for polar educators to build on each year. Through close collaboration with a number of partners. Antarctica Day activities have included: a Polar Film Festival convened by The Explorers Club; live sessions connecting classrooms with scientists in Antarctica thanks to PolarTREC and ARCUS; an international activity that involved children from 13 countries who created over 600 flags which exemplify Antarctica Day (these were actually flown in Antarctica with signed certificates then returned to the classes); a map where Antarctica Day participants all over the world could share what they were doing; an Antarctic bird count

  9. Observed Volume Fluxes in the Bosphorus Strait

    Science.gov (United States)

    2011-01-01

    Tugrul et al, 2002]. [4] The United States Naval Research Laboratory (NRL) and the NATO Undersea Research Center ( NURC ) in col- laboration with the...Turkish Navy Office of Navigation, Hydrography and Oceanography deployed two mooring sections in the Bosphorus Strait as a part of the TSS08 ( NURC

  10. Bottom fauna of the Malacca Strait

    Digital Repository Service at National Institute of Oceanography (India)

    Parulekar, A.H.; Ansari, Z.A.

    Bottom fauna of Malacca Strait (connecting the Indian Ocean with Pacific) in the depth range of 80 to 1350 m, is dominated by meiofauna which exceeds macrofauna by 12.5 times in weight and by more than 780 times in population density. Standing crop...

  11. Glaciers of Antarctica

    Science.gov (United States)

    Williams, Richard S.; Ferrigno, Jane G.

    1988-01-01

    Of all the world?s continents Antarctica is the coldest, the highest, and the least known. It is one and a half times the size of the United States, and on it lies 91 percent (30,109,800 km3) of the estimated volume of all the ice on Earth. Because so little is known about Antarctic glaciers compared with what is known about glaciers in populated countries, satellite imagery represents a great leap forward in the provision of basic data. From the coast of Antarctica to about 81?south latitude, there are 2,514 Landsat nominal scene centers (the fixed geographic position of the intersection of orbital paths and latitudinal rows). If there were cloud-free images for all these geographic centers, only about 520 Landsat images would be needed to provide complete coverage. Because of cloud cover, however, only about 70 percent of the Landsat imaging area, or 55 percent of the continent, is covered by good quality Landsat images. To date, only about 20 percent of Antarctica has been mapped at scales of 1:250,000 or larger, but these maps do include about half of the coastline. The area of Antarctica that could be planimetrically mapped at a scale of 1:250,000 would be tripled if the available Landsat images were used in image map production. This chapter contains brief descriptions and interpretations of features seen in 62 carefully selected Landsat images or image mosaics. Images were chosen on the basis of quality and interest; for this reason they are far from evenly spaced around the continent. Space limitations allow less than 15 percent of the Landsat imaging area of Antarctica to be shown in the illustrations reproduced in this chapter. Unfortunately, a wealth of glaciological and other features of compelling interest is present in the many hundreds of images that could not be included. To help show some important features beyond the limit of Landsat coverage, and as an aid to the interpretation of certain features seen in the images, 38 oblique aerial photographs

  12. Gliders in the Fram Strait Observatory

    Science.gov (United States)

    Beszczynska-Möller, Agnieszka; Fahrbach, Eberhard; Schauer, Ursula; Rohr, Harald; Lee, Craig

    2013-04-01

    Variability of oceanic advective fluxes through Fram Strait, one of the main gateways to the Arctic Ocean, has been monitored since 1997 by the array of 16 moorings and summer hydrographic sections. The main focus is on the inflow of warm Atlantic waters from the Nordic Seas, the only source of heat for the Arctic Ocean, and on the freshwater outflow to the North Atlantic. However, spatial resolution of the moored array, which varies from 10 to 30 km, is not sufficient to resolve the mesoscale variability of the complex, topographically flow through the strait. In the recently established multidisciplinary Fram Strait Observatory a combination of oceanographic observations by moorings and gliders with acoustic tomography measurements and the eddy-resolving numerical model will provide a new tool to assess the contribution of mesoscale dynamics to the variability of oceanic fluxes through Fram Strait. Since 2007, in the framework of the EU DAMOCLES and ACOBAR projects, the long-term moored observations in Fram Strait have been complemented with repeated glider sections. During eight summer and autumn missions the oceanographic data with high spatial resolution were collected down to 1000 m by Seagliders profiling along the moored array. Here we report on the results from five years of gliders measurements and a comparison of glider data to observations from moorings and ship-borne CTD sections. The special attention is paid to measurements in the West Spitsbergen Current, where gliders have to operate in the strong current regime (occasional events up to 1 m/s). Spatially averaged glider data were also applied in the finite element inverse model FEMSECT and preliminary results are presented. Future plans envisage a substitution of the upper part of moored array with repeated glider sections to achieve year-round glider operations in the partially sea-ice covered region. Since 2010 the array of RAFOS sources and tomographic sources providing RAFOS signal with

  13. Cosmology from Antarctica

    CERN Document Server

    Wilson, Robert W

    2008-01-01

    Observation of the CMB is central to observational cosmology, and the Antarctic Plateau is an exceptionally good site for this work. The first attempt at CMB observations from the Plateau was an expedition to the South Pole in December 1986 by the Radio Physics Research group at Bell Laboratories. Sky noise and opacity were measured. The results were sufficiently encouraging that in the Austral summer of 1988-1989, three CMB groups participated in the "Cucumber" campaign, where a temporary site dedicated to CMB anisotropy measurements was set up 2 km from South Pole Station. Winter-time observations became possible with the establishment in 1990 of the Center for Astrophysical Research in Antarctica (CARA), a National Science Foundation Science and Technology Center. CARA developed year-round observing facilities in the "Dark Sector", a section of Amundsen-Scott South Pole Station dedicated to astronomical observations. CARA scientists fielded several astronomical instruments: AST/RO, SPIREX, White Dish, Pyth...

  14. Antarctica: The Next Decade

    Science.gov (United States)

    Rowley, Peter D.

    Laurence M. Gould, in charge of United States efforts during the International Geophysical Year (IGY, 1957-1958) and a longterm spokesman for Antarctic science, once remarked that it was the cooperative efforts during the IGY in Antarctica, “coldest of all the continents, that witnessed the first thawing of the cold war.”The Antarctic Treaty, which governs all activities on the continent, was an outgrowth of the IGY. The Treaty—the model international agreement for peaceful cooperation—was signed in 1959 and became effective in 1961. As it nears its historic 30-year anniversary, it has been the subject of a blitz of recent publications, partly because of a general misapprehension that the Treaty might “expire” then and partly the result of controversial negotiations on the recently (June 1988) adopted Convention on the Regulation of Antarctic Mineral Resource Activities (CRAMRA).

  15. Landscape evolution of Antarctica

    Science.gov (United States)

    Jamieson, S.S.R.; Sugden, D.E.

    2007-01-01

    The relative roles of fluvial versus glacial processes in shaping the landscape of Antarctica have been debated since the expeditions of Robert Scott and Ernest Shackleton in the early years of the 20th century. Here we build a synthesis of Antarctic landscape evolution based on the geomorphology of passive continental margins and former northern mid-latitude Pleistocene ice sheets. What makes Antarctica so interesting is that the terrestrial landscape retains elements of a record of change that extends back to the Oligocene. Thus there is the potential to link conditions on land with those in the oceans and atmosphere as the world switched from a greenhouse to a glacial world and the Antarctic ice sheet evolved to its present state. In common with other continental fragments of Gondwana there is a fluvial signature to the landscape in the form of the coastal erosion surfaces and escarpments, incised river valleys, and a continent-wide network of river basins. A selective superimposed glacial signature reflects the presence or absence of ice at the pressure melting point. Earliest continental-scale ice sheets formed around 34 Ma, growing from local ice caps centered on mountain massifs, and featured phases of ice-sheet expansion and contraction. These ice masses were most likely cold-based over uplands and warm-based across lowlands and near their margins. For 20 million years ice sheets fluctuated on Croll-Milankovitch frequencies. At ~14 Ma the ice sheet expanded to its maximum and deepened a preexisting radial array of troughs selectively through the coastal mountains and eroded the continental

  16. Earth - Ross Ice Shelf, Antarctica

    Science.gov (United States)

    1991-01-01

    This color picture of Antarctica is one part of a mosaic of pictures covering the entire Antarctic continent taken during the hours following Galileo's historic first encounter with its home planet. The view shows the Ross Ice Shelf. An occasional mountain can be seen poking through the ice. It is late spring in Antarctica, so the sun never sets on the frigid, icy continent. This picture was taken on December 8, 1990.

  17. Solar Eclipses Observed from Antarctica

    OpenAIRE

    2013-01-01

    Aspects of the solar corona are still best observed during totality of solar eclipses, and other high-resolution observations of coronal active regions can be observed with radio telescopes by differentiation of occultation observations, as we did with the Jansky Very Large Array for the annular solar eclipse of 2012 May 20 in the US. Totality crossing Antarctica included the eclipse of 2003 November 23, and will next occur on 2021 December 4; annularity crossing Antarctica included the eclip...

  18. Accurate determination of surface reference data in digital photographs in ice-free surfaces of Maritime Antarctica.

    Science.gov (United States)

    Pina, Pedro; Vieira, Gonçalo; Bandeira, Lourenço; Mora, Carla

    2016-12-15

    The ice-free areas of Maritime Antarctica show complex mosaics of surface covers, with wide patches of diverse bare soils and rock, together with various vegetation communities dominated by lichens and mosses. The microscale variability is difficult to characterize and quantify, but is essential for ground-truthing and for defining classifiers for large areas using, for example high resolution satellite imagery, or even ultra-high resolution unmanned aerial vehicle (UAV) imagery. The main objective of this paper is to verify the ability and robustness of an automated approach to discriminate the variety of surface types in digital photographs acquired at ground level in ice-free regions of Maritime Antarctica. The proposed method is based on an object-based classification procedure built in two main steps: first, on the automated delineation of homogeneous regions (the objects) of the images through the watershed transform with adequate filtering to avoid an over-segmentation, and second, on labelling each identified object with a supervised decision classifier trained with samples of representative objects of ice-free surface types (bare rock, bare soil, moss and lichen formations). The method is evaluated with images acquired in summer campaigns in Fildes and Barton peninsulas (King George Island, South Shetlands). The best performances for the datasets of the two peninsulas are achieved with a SVM classifier with overall accuracies of about 92% and kappa values around 0.89. The excellent performances allow validating the adequacy of the approach for obtaining accurate surface reference data at the complete pixel scale (sub-metric) of current very high resolution (VHR) satellite images, instead of a common single point sampling. Copyright © 2016 Elsevier B.V. All rights reserved.

  19. Knowledge hubs along the straits of Malacca

    OpenAIRE

    Evers, Hans-Dieter; Hornidge, Anna-Katharina

    2007-01-01

    World history has known areas of relative isolation and areas of high intensity of cultural interaction. The Mediterranean Sea, the Silk Road or the Straits of Malacca can be cited as such crucial contact zones. Within these areas, centres sprung up that served as interfaces between cultures and societies. These “hubs” as we would like to call them, emerged at various points throughout the contact zones, rose to prominence and submerged into oblivion due to a variety of natural calamities or ...

  20. My IGY in Antarctica

    Science.gov (United States)

    Bentley, Charles

    2012-01-01

    Dr Charles Bentley is the A.P. Crary Professor Emeritus of Geophysics, Department of Geology and Geophysics, University of Wisconsin-Madison. Dr. Bentley joined the Arctic Institute of North America in 1956 to participate in International Geophysical Year (IGY)-related activities in the Antarctic. He wintered over consecutively in 1957 and 1958 at Byrd Station, a station in the interior of West Antarctica that housed 24 men each winter - 12 Navy support people and 12 civilian scientists/technicians. During the austral summers, he also participated in over-snow traverses, first as co-leader, then leader (the other coleader went home after the first year). These traverses consisted of six men and three vehicles, and lasted several months. These traverses covered more than 1609 kilometers (1000 miles) of largely unmapped and unphotographed terrain. During these traverses, connections to Byrd Station were by radio (daily, when the transmission conditions were good enough) and roughly every 2 weeks by resupply flight.

  1. Pulsating star research from Antarctica

    Science.gov (United States)

    Chadid, Merieme

    2017-09-01

    This invited talk discusses the pulsating star research from the heart of Antarctica and the scientific polar challenges in the extreme environment of Antarctica, and how the new polar technology could cope with unresolved stellar pulsation enigmas and evolutionary properties challenges towards an understanding of the mysteries of the Universe. PAIX, the first robotic photometer Antarctica program, has been successfully launched during the polar night 2007. This ongoing program gives a new insight to cope with unresolved stellar enigmas and stellar oscillation challenges with a great opportunity to benefit from an access to the best astronomical site on Earth, Dome C. PAIX achieves astrophysical measurement time-series of stellar fields, challenging photometry from space. A continuous and an uninterrupted series of multi-color photometric observations has been collected each polar night - 150 days - without regular interruption, Earth's rotation effect. PAIX shows the first light curve from Antarctica and first step for the astronomy in Antarctica giving new insights in remote polar observing runs and robotic instruments towards a new technology.

  2. On the dynamics of strait flows: an ocean model study of the Aleutian passages and the Bering Strait

    Science.gov (United States)

    Ezer, Tal; Oey, Lie-Yauw

    2013-03-01

    A high-resolution numerical ocean circulation model of the Bering Sea (BS) is used to study the natural variability of the BS straits. Three distinct categories of strait dynamics have been identified: (1) Shallow passages such as the Bering Strait and the Unimak Passage have northward, near barotropic flow with periodic pulses of larger transports; (2) wide passages such as Near Straits, Amukta Pass, and Buldir Pass have complex flow patterns driven by the passage of mesoscale eddies across the strait; and (3) deep passages such as Amchitka Pass and Kamchatka Strait have persistent deep return flows opposite in direction to major surface currents; the deep flows persist independent of the local wind. Empirical orthogonal function analyses reveal the spatial structure and the temporal variability of strait flows and demonstrate how mesoscale variations in the Aleutian passages influence the Bering Strait flow toward the Arctic Ocean. The study suggests a general relation between the barotropic and baroclinic Rossby radii of deformations in each strait, and the level of flow variability through the strait, independent of geographical location. The mesoscale variability in the BS seems to originate from two different sources: a remote origin from variability in the Alaskan Stream that enters the BS through the Aleutian passages and a local origin from the interaction of currents with the Bowers Ridge in the Aleutian Basin. Comparisons between the flow in the Aleutian passages and flow in other straits, such as the Yucatan Channel and the Faroe Bank Channel, suggest some universal topographically induced dynamics in strait flows.

  3. What processes control the net currents through shallow straits? A review with application to the Bohai Strait, China

    Science.gov (United States)

    Li, Yanfang; Wolanski, Eric; Zhang, Hua

    2015-06-01

    We review the key processes controlling the net water circulation in shallow straits. The circulation is mainly barotropic, driven by the difference in mean sea level and tides on either side of the strait, the wind, the meandering of the currents in the adjoining seas, the bathymetry including the shape and width of the mouths and the presence of narrows, shoals, sills, islands, and lateral embayments. As the oceanography forcing can be non-synchronised on either side of the strait, the resulting net currents through the strait may appear chaotic. We apply these findings to the net circulation through the Bohai Strait in China using local wind, remote-sensing data of currents and sea level, and a hydrodynamic model. The net currents through the Bohai Strait were episodic. They were largest during winter storms when the wind generated a cyclonic coastal current in the northern Yellow Sea that flowed across the width of the Bohai Strait. Like the Luzon Strait, this current meandered and a branch of the current intruded into the northern Bohai Strait along the deeper channel. The wind set-up in the Bohai Sea and the wind-driven longshore current in the southern Bohai Sea generated a seaward flow through the southern Bohai Strait, somewhat like in Irbe Strait. As with the straits of the Seto Inland Sea, stagnation occurred in some embayments. As in the Torres Strait, the islands in the southern Bohai Strait retarded the net flow and increased the width of the outflow zone. These flows were also modulated at very long periods (∼60 days) by long waves in the Yellow Sea, possibly generated by meandering of the Kuroshio Current that created an additional sea level slope through the strait. The transit time in the Bohai Strait was 60 and 10 days, respectively, during calm weather and winter storms. The residence time in the Bohai Sea was estimated to be about 1.68 years by the LOICZ model and 1.56 years by the hydrodynamic model, and the influence of the river runoff

  4. Offshore finfish mariculture in the Strait of Juan de Fuca

    Energy Technology Data Exchange (ETDEWEB)

    Rensel, Jack; Kiefer, Dale; Forster, John R.; Woodruff, Dana L.; Evans, Nathan R.

    2007-10-07

    Finfish mariculture has existed in the U.S. Pacific Northwest for over thirty years, but for the past 15 years most effort has focused on culture of Atlantic salmon in protected, inshore cage sites. The Strait of Juan de Fuca (the "Strait") is a large area with relatively sparce shoreline development and several apparent advantages for mariculture using offshore technology.

  5. 33 CFR 80.1385 - Strait of Juan de Fuca.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Strait of Juan de Fuca. 80.1385 Section 80.1385 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Thirteenth District § 80.1385 Strait of Juan de Fuca. The 72 COLREGS shall apply on all waters of...

  6. Assessment Of Trophic Status In Bali Strait

    Directory of Open Access Journals (Sweden)

    Umi Zakiyah

    2016-04-01

    Full Text Available The nutrient content in Banyuwangi coastal environment mostly caused by human activities along the coastal area of Bali strait especially in Banyuwangi surrounding areas. The change of organic element content in waters will directly affect plankton community structure and the aquatic trophic level. The aimed of this research were to analyze the plankton community structure, and to observe the quality of aquatic and determine Bali Strait especially Banyuwangi coastal area trophic level. This research was done in October 2015 at Banyuwangi coastal area. Methods used in this research was descriptive with seawater sampling for water quality analysis of several parameter such as nitrates (NO3, phosphates (PO4, TOM (Total Organic Matter and Chlorophyll-a, meanwhile other parameters were, temperature, pH, Dissolved Oxygen dan salinity from three different depth of three different stations, coastal area of Bangsring, Tandjung Wangi and Muncar. The results for water quality parameters showed that Bangsring coastal area was the most  healthy waters compared to Bangsring and Muncar. Meanwhile, there were tendency that the concentration mostly high in the surface and decrease along with the deeper depth. This condition presumed caused by the ARLINDO current that passed through Bali strait. Phytoplankton identified and calculated consisted of 3 division, namely Chlorophyta, Chrysophyta, and Cyanophyta with total density ranges between 4-2888 ind/ml. The value of diversity index phytoplankton (H’ ranges between 0,3-0,7. Based on the result it can be concluded that Banyuwangi coastal areas were at throphic level of  oligotrophic tended to mesotrophic in northern part and eutrophic especially in Muncar. Thus, it was suggested for the Government to prevent this area becoming more polluted in the future.

  7. Antarctica: Chile’s Claim,

    Science.gov (United States)

    1987-01-01

    Marie Byrd Land is be- low sea level and covered by a sheath of ice 600 to 4,000 meters (1,968 to 13,120 feet) thick. * This sheath of ice extends below...Channel to sulphurs lead, silver stratiform bodies Spring Point, Trans- in sedimentary Antarctica Mountain and volcanic rocks Ultra- Chrome , Stratified en

  8. Surface winds over West Antarctica

    Science.gov (United States)

    Bromwich, David

    1993-01-01

    Five winter months (April-August 1988) of thermal infrared satellite images were examined to investigate the occurrence of dark (warm) signatures across the Ross Ice Shelf in the Antarctic continent. These features are inferred to be generated by katabatic winds that descend from southern Marie Byrd Land and then blow horizontally across the ice shelf. Significant mass is added to this airstream by katabatic winds blowing from the major glaciers that flow through the Transantarctic Mountains from East Antarctica. These negatively buoyant katabatic winds can reach the northwestern edge of the shelf - a horizontal propagation distance of up to 1,000 km - 14 percent of the time. Where the airstream crosses from the ice shelf to the ice-covered Ross Sea, a prominent coastal polynya is formed. Because the downslope buoyancy force is near zero over the Ross Ice Shelf, the northwestward propagation of the katabatic air mass requires pressure gradient support. The study shows that the extended horizontal propagation of this atmospheric density current occurred in conjunction with the passage of synoptic cyclones over the southern Amundsen Sea. These cyclones can strengthen the pressure gradient in the interior of West Antarctica and make the pressure field favorable for northwestward movement of the katabatic winds from West Antarctica across the ice shelf in a geostrophic direction. The glacier winds from East Antarctica are further accelerated by the synoptic pressure gradient, usually undergo abrupt adjustment beyond the exit to the glacier valley, and merge into the mountain-parallel katabatic air mass.

  9. Biogeochemical cycling in the Taiwan Strait

    Digital Repository Service at National Institute of Oceanography (India)

    Naik, H.; Chen, C-T.A.

    is attributed to the retreat of remnant winter water that flows northward (Chen and Sheu, 2006) and in the northern transect (NTS) to topographically driven upwelling (Hu et al., 1980). The upwelling feature in the mid-strait 3.1. Hydrography and Parsons, 1972...-distilled, Millipore water contain- ing 1% MgCO 3 and then stored at C020 C14 C for further analysis in the shore laboratory. A Turner Designs model 10-AU fluo- rometer measured Chl a after extraction with 90% acetone (Strickland and Parsons, 1972). 3. Results The data...

  10. Pine Island Glacier, Antarctica

    Science.gov (United States)

    2001-01-01

    This pair of MISR images of the Pine Island Glacier in western Antarctica was acquired on December 12, 2000 during Terra orbit 5246. At left is a conventional, true-color image from the downward-looking (nadir) camera. The false-color image at right is a composite of red band data taken by the MISR forward 60-degree, nadir, and aftward 60-degree cameras, displayed in red, green, and blue colors, respectively. Color variations in the left (true-color) image highlight spectral differences. In the multi-angle composite, on the other hand, color variations act as a proxy for differences in the angular reflectance properties of the scene. In this representation, clouds show up as light purple. Blue to orange gradations on the surface indicate a transition in ice texture from smooth to rough. For example, the bright orange 'carrot-like' features are rough crevasses on the glacier's tongue. In the conventional nadir view, the blue ice labeled 'rough crevasses' and 'smooth blue ice' exhibit similar coloration, but the multi-angle composite reveals their different textures, with the smoother ice appearing dark purple instead of orange. This could be an indicator of different mechanisms by which this ice is exposed. The multi-angle view also reveals subtle roughness variations on the frozen sea ice between the glacier and the open water in Pine Island Bay.To the left of the 'icebergs' label are chunks of floating ice. Additionally, smaller icebergs embedded in the frozen sea ice are visible below and to the right of the label. These small icebergs are associated with dark streaks. Analysis of the illumination geometry suggests that these streaks are surface features, not shadows. Wind-driven motion and thinning of the sea ice in the vicinity of the icebergs is one possible explanation.Recently, Robert Bindschadler, a glaciologist at the NASA Goddard Space Flight Center discovered in Landsat 7 imagery a newly-formed crack traversing the Pine Island Glacier. This crack is

  11. Denaturing gradient gel electrophoresis fingerprinting of soil bacteria in the vicinity of the Chinese Great Wall Station, King George Island, Antarctica.

    Science.gov (United States)

    Pan, Qi; Wang, Feng; Zhang, Yang; Cai, Minghong; He, Jianfeng; Yang, Haizhen

    2013-08-01

    Bacterial diversity was investigated in soil samples collected from 13 sites around the Great Wall Station, Fildes Peninsula, King George Island, Antarctica, using denaturing gradient gel electrophoresis (DGGE) of 16S rRNA genes. The classes alpha-, beta-, and gamma-Proteobacteria, as well as the phylum Actinobacteria, were found to be the dominant bacteria in the soils around the Great Wall Station. Although the selected samples were not contaminated by oil, a relationship between soil parameters, microbial biodiversity, and human impact was still seen. Sample sites in human impacted areas showed lower bacterial biodiversity (average H' = 2.65) when compared to non-impacted sites (average H' = 3.05). There was no statistically significant correlation between soil bacterial diversity and total organic carbon (TOC), total nitrogen, or total phosphorus contents of the soil. Canonical correlation analysis showed that TOC content was the most important factor determining bacterial community profiles among the measured soil parameters. In conclusion, microbial biodiversity and community characteristics within relatively small scales (1.5 km) were determined as a function of local environment parameters and anthropogenic impact.

  12. Denaturing gradient gel electrophoresis fingerprinting of soil bacteria in the vicinity of the Chinese Great Wall Station, King George Island, Antarctica

    Institute of Scientific and Technical Information of China (English)

    Qi Pan; Feng Wang; Yang Zhang; Minghong Cai; Jianfeng He; Haizhen Yang

    2013-01-01

    Bacterial diversity was investigated in soil samples collected from 13 sites around the Great Wall Station,Fildes Peninsula,King George Island,Antarctica,using denaturing gradient gel electrophoresis (DGGE) of 16S rRNA genes.The classes α-,β-,and γ-Proteobacteria,as well as the phylum Actinobacteria,were found to be the dominant bacteria in the soils around the Great Wall Station.Although the selected samples were not contaminated by oil,a relationship between soil parameters,microbial biodiversity,and human impact was still seen.Sample sites in human impacted areas showed lower bacterial biodiversity (average H' =2.65) when compared to non-impacted sites (average H' =3.05).There was no statistically significant correlation between soil bacterial diversity and total organic carbon (TOC),total nitrogen,or total phosphorus contents of the soil.Canonical correlation analysis showed that TOC content was the most important factor determining bacterial community profiles among the measured soil parameters.In conclusion,microbial biodiversity and community characteristics within relatively small scales (1.5 km) were determined as a function of local environment parameters and anthropogenic impact.

  13. The bottom water exchange between the Singapore Strait and the West Johor Strait

    Science.gov (United States)

    Sun, Yunfang; Eltahir, Elfatih; Malanotte-Rizzoli, Paola

    2017-08-01

    As a part of the border between Singapore and Malaysia, the West Johor Strait (WJS) suffered newly from harmful algal blooms. There is no previous study showing the source of the nutrients in the WJS. This paper is investigating the possible water exchange between the water in the WJS and the bottom water in Singapore Strait. This paper adopts a two-level nesting atmosphere-ocean coupled models to downscale the global atmosphere-ocean model into the Singapore coastal water, keeping the large-scale and long-term ocean and climate circulation signals and the advantages of the high-resolution. Based on the high-resolution ocean circulation fields, a Lagrangian particle tracking model is used to trace the Singapore Strait's bottom water movement and the water mixing in the WJS. The results showed that the numerical models well resolved the Singapore coastal water regional circulation. There is a small but significant bottom water (1.25%) transport from the Singapore Strait to the WJS, which occurs from the southwest coastline of Singapore. The bottom water in the Singapore Strait prefers to enter the WJS during the spring tide and the flood period, and stay in Johor Strait for 6.4 days. The spring tide is the first-order factor for the water vertical mixing in the WJS, the wind is also very important for the vertical mixing especially in neap tide condition. An overall very important factor is the light perturbation. With the strongest vertical mixing of nutrients and bottom sediments due to the spring tide, the latter ones may inhibit the light penetration during the spring tide and reduce the algal bloom. The light penetration otherwise is greater during the neap tide, when the winds are the most important factor and hence favor the algal bloom. With the strongest wind in February and the longest permanence time in June and the sufficient nutrient supply in February and June, the most serious algal blooms may happen in February and June in the WJS.

  14. Glacial evolution in King George and Livingston Islands (Antarctica) since the Last Glacial Maximum based on cosmogenic nuclide dating and glacier surface reconstruction - CRONOANTAR project

    Science.gov (United States)

    Ruiz Fernández, Jesús; Oliva, Marc; Fernández Menéndez, Susana del Carmen; García Hernández, Cristina; Menéndez Duarte, Rosa Ana; Pellitero Ondicol, Ramón; Pérez Alberti, Augusto; Schimmelpfennig, Irene

    2017-04-01

    CRONOANTAR brings together researchers from Spain, Portugal, France and United Kingdom with the objective of spatially and temporally reconstruct the deglaciation process at the two largest islands in the South Shetlands Archipelago (Maritime Antarctica), since the Global Last Glacial Maximum. Glacier retreat in polar areas has major implications at a local, regional and even planetary scale. Global average sea level rise is the most obvious and socio-economically relevant, but there are others such as the arrival of new fauna to deglaciated areas, plant colonisation or permafrost formation and degradation. This project will study the ice-free areas in Byers and Hurd peninsulas (Livingston Island) and Fildes and Potter peninsulas (King George Island). Ice-cap glacier retreat chronology will be revealed by the use of cosmogenic isotopes (mainly 36Cl) on glacially originated sedimentary and erosive records. Cosmogenic dating will be complemented by other dating methods (C14 and OSL), which will permit the validation of these methods in regions with cold-based glaciers. Given the geomorphological evidences and the obtained ages, a deglaciation calendar will be proposed and we will use a GIS methodology to reconstruct the glacier extent and the ice thickness. The results emerging from this project will allow to assess whether the high glacier retreat rates observed during the last decades were registered in the past, or if they are conversely the consequence (and evidence) of the Global Change in Antarctica. Acknowledgements This work has been funded by the Spanish Ministry of Economy, Industry and Competitiveness (Reference: CTM2016-77878-P).

  15. Chlorinated biphenyls and pesticides in migrating and resident seabirds from East and West Antarctica.

    Science.gov (United States)

    Corsolini, Simonetta; Borghesi, Nicoletta; Ademollo, Nicoletta; Focardi, Silvano

    2011-11-01

    The unhatched eggs of the following seabirds were analyzed to quantify PCBs, hexachlorobenzene (HCB), α-, β-, γ-, δ-hexachlorocyclohexanes (HCHs), o,p' and p,p' isomers of DDT, DDD and DDE: resident Adèlie (Pygoscelis adèliae, ADPE) and Emperor (Aptenodytes forsteri, EMPE) penguins, migrating snow petrel (Pagodroma nivea, SNPT) and South Polar skua (Catharacta maccormicki, SPSK) from the Ross Sea (East Antarctica); and migrating Brown skua (Catharacta antartica, BRSK) and resident ADPE from the Brainsfield Strait (West Antarctica). The general aims were to evaluate the contaminant accumulation in eggs of migrating and resident species in the two study areas, and to compare levels in penguins and skuas nesting in East and West Antarctica. PCB congener and HCH and DDT isomer profiles were also assessed. Comparisons were evaluated using seven PCB congeners (IUPAC nos. 28, 52, 101, 118+149, 138, 153, and 180), p,p'-DDE, ΣDDTs, and ΣHCHs. Higher contaminant concentrations were detected in migrating seabirds (South polar skua and brown skua)>sub-Antarctic species (snow petrel)>Antarctic species (penguins) from both the sampling sites, suggesting contamination events at lower latitudes for those birds migrating northward. HCHs showed the lowest concentrations in all species (from 0.03±0.03 ng/g wet wt in SPSK to 1.81±1.23 ng/g wet wt in ADPE from West Antarctica), and PCBs were the most abundant contaminants (from 4.34±2.15 ng/g wet wt. in EMPE to 53.41±19.61 ng/g wet wt. in brown skua). Among pesticides, it is relevant the detection of p,p'-DDT in Adèlie penguin from West Antarctica and in both species of skua; the detection of this pesticide can confirm its actual use in certain malaria-endemic countries from where it is transferred through the long range transport to the polar regions. Contaminants did not show any significant temporal trend during a ten year time span, from 1994/95 to 2004/05, in organisms collected in East Antarctica and they did not

  16. Atmospheric forcing of salinity in the overflow of Denmark Strait

    Directory of Open Access Journals (Sweden)

    J. Holfort

    2007-09-01

    Full Text Available The temporal evolution of the characteristics of Denmark Strait Overflow Water (DSOW is reconstructed using hydrographic data and compared with possible atmospheric forcing mechanisms. It is concluded that the main factor influencing the DSOW characteristics at a time scale of one to several years is the difference in mean sea level pressure across Denmark Strait or, in other words, the wind along Denmark Strait. At these time scales upstream changes in the characteristics of the different water masses involved in the formation of DSOW are only of minor importance. The main process responsible for the observed salinity changes in the DSOW is mixing in Denmark Strait. Triggered by the wind, different water masses contribute with changing amounts to the formation of DSOW, leading to the observed changes in the salinity of DSOW.

  17. Strait of Juan de Fuca 1 arc-second DEM

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The 1-second Strait of Juan de Fuca Washington Elevation Grid provides bathymetric data in ASCII raster format of 1-second resolution in geographic coordinates. This...

  18. Strait of Juan de Fuca 6 arc-second DEM

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The 6-second Strait of Juan de Fuca Washington Elevation Grid provides bathymetric data in ASCII raster format of 6-second resolution in geographic coordinates. This...

  19. Strait of Juan de Fuca 36 arc-second DEM

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The 36-second Strait of Juan de Fuca Washington Elevation Grid provides bathymetric data in ASCII raster format of 36-second resolution in geographic coordinates....

  20. Potential methane reservoirs beneath Antarctica.

    Science.gov (United States)

    Wadham, J L; Arndt, S; Tulaczyk, S; Stibal, M; Tranter, M; Telling, J; Lis, G P; Lawson, E; Ridgwell, A; Dubnick, A; Sharp, M J; Anesio, A M; Butler, C E H

    2012-08-30

    Once thought to be devoid of life, the ice-covered parts of Antarctica are now known to be a reservoir of metabolically active microbial cells and organic carbon. The potential for methanogenic archaea to support the degradation of organic carbon to methane beneath the ice, however, has not yet been evaluated. Large sedimentary basins containing marine sequences up to 14 kilometres thick and an estimated 21,000 petagrams (1 Pg equals 10(15) g) of organic carbon are buried beneath the Antarctic Ice Sheet. No data exist for rates of methanogenesis in sub-Antarctic marine sediments. Here we present experimental data from other subglacial environments that demonstrate the potential for overridden organic matter beneath glacial systems to produce methane. We also numerically simulate the accumulation of methane in Antarctic sedimentary basins using an established one-dimensional hydrate model and show that pressure/temperature conditions favour methane hydrate formation down to sediment depths of about 300 metres in West Antarctica and 700 metres in East Antarctica. Our results demonstrate the potential for methane hydrate accumulation in Antarctic sedimentary basins, where the total inventory depends on rates of organic carbon degradation and conditions at the ice-sheet bed. We calculate that the sub-Antarctic hydrate inventory could be of the same order of magnitude as that of recent estimates made for Arctic permafrost. Our findings suggest that the Antarctic Ice Sheet may be a neglected but important component of the global methane budget, with the potential to act as a positive feedback on climate warming during ice-sheet wastage.

  1. Characteristics of N2O Emissions from Vegetal Soils on Fildes Peninsula,Antarctica%南极菲尔德斯半岛植被土壤N2O排放特征

    Institute of Scientific and Technical Information of China (English)

    孙立广; 朱仁斌; 谢周清; 赵俊琳; 邢光熹; 施书莲; 杜丽娟

    2001-01-01

    应用密闭箱法首次测定了南极菲尔德斯半岛苔藓、地衣植被土壤N2O的排放通量,并估算了该半岛植被区土壤在夏季2个月内N2O的排放总量.结果表明:在晴天和雨天,苔藓土壤N2O的排放通量与温度有较好的响应关系,呈现单峰型变化趋势;但在雪天,与温度的变化不一致;苔藓、地衣这2种不同的植被土壤N2O排放通量日变化基本一致;温度是影响苔藓土壤N2O的排放通量季节变化的主要因子,同时还受降水的影响,干湿交替有利于N2O的排放;苔藓土壤N2O的排放总量为3.7152kg;地衣土壤N2O的排放总量为2.5344kg.由此可见,南极菲尔德斯半岛苔藓、地衣植被土壤N2O排放量虽然很小,但仍起着大气N2O源的作用.

  2. A novel adenovirus in Chinstrap penguins (Pygoscelis antarctica) in Antarctica.

    Science.gov (United States)

    Lee, Sook-Young; Kim, Jeong-Hoon; Park, Yon Mi; Shin, Ok Sarah; Kim, Hankyeom; Choi, Han-Gu; Song, Jin-Won

    2014-05-07

    Adenoviruses (family Adenoviridae) infect various organ systems and cause diseases in a wide range of host species. In this study, we examined multiple tissues from Chinstrap penguins (Pygoscelis antarctica), collected in Antarctica during 2009 and 2010, for the presence of novel adenoviruses by PCR. Analysis of a 855-bp region of the hexon gene of a newly identified adenovirus, designated Chinstrap penguin adenovirus 1 (CSPAdV-1), showed nucleotide (amino acid) sequence identity of 71.8% (65.5%) with South Polar skua 1 (SPSAdV-1), 71% (70%) with raptor adenovirus 1 (RAdV-1), 71.4% (67.6%) with turkey adenovirus 3 (TAdV-3) and 61% (61.6%) with frog adenovirus 1 (FrAdV-1). Based on the genetic and phylogenetic analyses, CSPAdV-1 was classified as a member of the genus, Siadenovirus. Virus isolation attempts from kidney homogenates in the MDTC-RP19 (ATCC® CRL-8135™) cell line were unsuccessful. In conclusion, this study provides the first evidence of new adenovirus species in Antarctic penguins.

  3. A Novel Adenovirus in Chinstrap Penguins (Pygoscelis antarctica in Antarctica

    Directory of Open Access Journals (Sweden)

    Sook-Young Lee

    2014-05-01

    Full Text Available Adenoviruses (family Adenoviridae infect various organ systems and cause diseases in a wide range of host species. In this study, we examined multiple tissues from Chinstrap penguins (Pygoscelis antarctica, collected in Antarctica during 2009 and 2010, for the presence of novel adenoviruses by PCR. Analysis of a 855-bp region of the hexon gene of a newly identified adenovirus, designated Chinstrap penguin adenovirus 1 (CSPAdV-1, showed nucleotide (amino acid sequence identity of 71.8% (65.5% with South Polar skua 1 (SPSAdV-1, 71% (70% with raptor adenovirus 1 (RAdV-1, 71.4% (67.6% with turkey adenovirus 3 (TAdV-3 and 61% (61.6% with frog adenovirus 1 (FrAdV-1. Based on the genetic and phylogenetic analyses, CSPAdV-1 was classified as a member of the genus, Siadenovirus. Virus isolation attempts from kidney homogenates in the MDTC-RP19 (ATCC® CRL-8135™ cell line were unsuccessful. In conclusion, this study provides the first evidence of new adenovirus species in Antarctic penguins.

  4. Seasonal Variability of Transport Through Gibraltar, Sicily and Corsica Straits

    Science.gov (United States)

    Béranger, K.; Mortier, L.; Crépon, M.

    We have investigated the transport variability through three major straits of the Mediterranean Sea (Gibraltar, Sicily, Corsica) with a very high resolution model of the Mediterranean Sea. A numerical simulation of the Mediterranean circulation has been done with a 1/16o horizontal grid mesh, 43 vertical z-level model. Initial hydrological conditions were provided by the Mediterranean MODB5 climatology. The model has been run eleven years. It has been forced in a yearly perpetual mode by the daily sea surface fluxes from European Centre for Medium-range Weather Forecasts analysis during the year March 1998 - February 1999. This study has been supported by the french MERCA- TOR project and SHOM. We grateful the PAM team of CERFACS (Toulouse, France). Analysis is focused on three major straits which play an important role in control- ling the circulation through mass transport exchanges. Model results are compared to recent observations and good agreement is obtained. It demonstrates advantages to improve resolution in numerical models. Gibraltar and Sicily strait transports are largely baroclinic. The transport through the Gibraltar Strait is forced by density difference between the Atlantic Ocean and the Mediterranean Sea. Atlantic water (AW) penetrates the Mediterranean Sea while Mediterranean Outflow Water flows into the Atlantic Ocean. This transport is hy- draulically maximal, with a semi-annual signal, and its seasonal variation is weak. The Sicily Strait transport is probably first forced by the AW coming from the West rather than the density gradient between the western and eastern mediterranean seas. AW inflow (i.e. Eastern Mediterranean Overflow Water outflow) is maximum in late Fall and minimum in late Winter. In opposite to previous straits, the northward Cor- sica Strait transport presents strong seasonal variability, and thus a strong barotropic component related to the wind stress curl.

  5. Geodetic surveys in Messina straits area

    Science.gov (United States)

    Baldi, P.; Achilli, V.; Mulargia, F.; Broccio, F.

    1983-03-01

    By using the fit of theoretical displacements on a fault according to Mindlin and Cheng (1950) dislocation theory, the vertical deformation field (maximum subsidence of 70 cm) associated to the Dec. 28 1908 Messina M=7.0 earthquake is compared to the results of a spirit levelling survey that we performed in the Messina Straits area in 1981 1982. The differences in level from the last levelling campaign in the area, completed in 1970, show that the coastlines have undergone a moderate differential subsidence of about 1 mm/year in the last decade. This is in agreement with the trend observed around 1908 and with the data of the Messina tide-gauge relative to the period 1897 1908 and 1910 1918. The lack of data in the period 1918 1970 does not allow definite conclusions about the vertical tectonic deformations in the area. Recent data on planimetric deformations have shown a South-North relative motion of Sicily. A comparison with the theoretical displacements indicates that a pure dip-slip of 4 cm on the 1908 fault system does explain the observed vertical deformation, but not the horizontal.

  6. Changes in the Composition of the Fram Strait Freshwater Outflow

    Science.gov (United States)

    Dodd, Paul; Granskog, Mats; Fransson, Agneta; Chierici, Melissa; Stedmon, Colin

    2016-04-01

    Fram Strait is the largest gateway and only deep connection between the Arctic Ocean and the subpolar oceans. Monitoring the exchanges through Fram Strait allows us to detect and understand current changes occurring in the Arctic Ocean and to predict the effects of those changes on the Arctic and Subarctic climate and ecosystems. Polar water, recirculating Atlantic Water and deeper water masses exported from the Arctic Ocean through western Fram Strait are monitored year-round by an array of moored instruments along 78°50'N, continuously maintained by the Norwegian Polar Institute since the 1990s. Complimentary annual hydrographic sections have been repeated along the same latitude every September. This presentation will focus on biogeochemical tracer measurements collected along repeated sections from 1997-2015, which can be used to identify freshwater from different sources and reveal the causes of variations in total volume of freshwater exported e. g.: pulses of freshwater from the Pacific. Repeated tracer sections across Fram Strait reveal significant changes in the composition of the outflow in recent years, with recent sections showing positive fractions of sea ice meltwater at the surface near the core of the EGC, suggesting that more sea ice melts back into the surface than previously. The 1997-2015 time series of measurements reveals a strong anti-correlation between run-off and net sea ice meltwater inventories, suggesting that run-off and brine may be delivered to Fram Strait together from a common source. While the freshwater outflow at Fram Strait typically exhibits a similar run-off to net sea ice meltwater ratio to the central Arctic Ocean and Siberian shelves, we find that the ratio of run-off to sea ice meltwater at Fram Strait is decreasing with time, suggesting an increased surface input of sea ice meltwater in recent years. In 2014 and 2015 measurements of salinity, δ18O and total alkalinity were collected from sea ice cores as well as the

  7. Recent accumulation rate at Dome A, Antarctica

    Institute of Scientific and Technical Information of China (English)

    HOU ShuGui; LI YuanSheng; XIAO CunDe; REN JiaWen

    2007-01-01

    Based on the horizon of β activity and the density profiles, recent accumulation rate at Dome A, Antarctica is calculated to be 0.023 m water equivalent per year. This value is comparative to the accumulation rates deduced from the other inland sites of Antarctica. Clear-sky precipitation (or diamond dust) dominates the total precipitation at Dome A region. We speculate Dome A as a potential site to discover the oldest ice in Antarctica due to its tremendous ice thickness (>3000 m), extremely low accumulation rate, and low ice velocity.

  8. Peaceful development of cross-strait relations,"one country two systems"Horizon

    Institute of Scientific and Technical Information of China (English)

    YanDekuan

    2015-01-01

    " one country, peaceful reunification" policy put forward, which has existed for more than 30 set. People have proposed the development of cross-strait peace framework. It is necessary for the development of cross-strait peace framework related to cross-strait cultural environment factors, international factors, the development of cross-strait past and future context, strategic and realistic basis for cross-strait interaction were analyzed and discussed. Made more scientific framework for peaceful development of cross-strait on this basis. The paper carried a Taiwanese perspective Islanders psychological and related factors. Unified attitude on the mainland were scanned. For cross-strait peace development context briefly comb. On this basis a simple thinking related factors. Peaceful development of cross-strait relations proposed framework Opinion.

  9. Reading the Planetary Archipelago of the Torres Strait

    Directory of Open Access Journals (Sweden)

    Elizabeth McMahon

    2013-05-01

    Full Text Available This essay makes use of the Western concept of the archipelago as a starting point for an examination of island to island relations in the Torres Strait, Australia, as they are rehearsed in the imaginary domain of story, in both its written and oral modes. The essay deploys Spivak’s notions of planetarity and Bloch’s concept of utopianism as ways of charting the relationship between two Torres Strait stories, one old, one new. In so doing, the essay seeks to identify the capacity of Torres Strait literature and storytelling to re-conceive relations of space and time and to acknowledge a spatial and temporal mobility running parallel to the circumscribed trajectories of late modernity.

  10. Tide and tidal current observation in the Karimata Strait

    Science.gov (United States)

    Wei, Zexun; Fang, Guohong; Sulistiyo, Budi; Dwi Susanto, R.; Setiawan, Agus; Rameyo Adi, Tukul; Qiao, Fangli; Fan, Bin; Li, Shujiang

    2013-04-01

    It is believed that the water exchanges between the South China Sea and the Indonesian Seas are significant, and play an important role in the water mass formation and air-sea interactions of both the South China Sea and Indonesian Seas. It has also been found that the current in Sunda Strait has been obvious seasonal variation, which indicates the water exchange between West Indonesian Seas and India Ocean. In order to make quantitative evaluation of the magnitudes of the exchange, the First Institute of Oceanography (FIO), China, the Agency for Marine and Fisheries Research, Indonesia, and the Lamont-Doheries Earth Observatory, USA established a collaborative program, "The South-China Sea-Indonesian Seas Transport/Exchange (SITE) and Impacts on Seasonal Fish Migration" in 2006. And, they extend and expand the cooperation to Sunda Strait in 2008, the title of the collaborative program was changed to "The South China Sea - Indonesian Seas Transport/Exchange (SITE) and Dynamics of Sunda and Lombok Straits, and Their Impacts on Seasonal Fish Migration". Till now, 12 joint cruises have been conducted since December, 2007. Ten Trawl-Resistant Bottom Mounts (TRBM) have been deployed in the Karimata and Sunda Straits. The TRBMs are equipped with ADCPs and tide gauges for measuring current profiles and sea levels, respectively. The temperature-salinity profiles were measured with ship-board CTD during the cruises. Data obtained in Karimata Strait revealed that a significant water mass transport. This indicates that the Karimata Strait throughflow can greatly impacts the circulation of both the South China Sea and the Indonesian Seas. The data obtained at the 5 stations alone the two sections in the Karimata Strait were used to study the tide and tidal currents in the Karimata Strait. 2 TRBMs were deployed at Section A, as well as 3 at Section B, which lies at the southeast of Section A. Station B1 is in the Gaspar Strait between Bangka Island and Belitung Island, Stations

  11. Iron Meteorites and Upwelling in Antarctica

    Science.gov (United States)

    Gourlay, B. S.; Behr, E.; Mardon, A.; Behr, E.

    2016-09-01

    In Antarctica, a meteorite stranding zone, stone meteorites are more common than iron. Dr. Evatt's team suggests that the heat conductivity of iron may be opposing the upwelling effects so iron meteorites sink under the ice unlike the stone ones.

  12. Geoethical approach to mineral activities in Antarctica

    Science.gov (United States)

    Talalay, Pavel

    2013-04-01

    Antarctica is the outermost from civilization space continent. From 14.0 million km2 of surface area about 98% of Antarctica is covered by ice that averages at least 1.6 km in thickness. Geologically, the continent is the least explored in the world, and it is almost absolutely unknown what mineral resources Antarctica has as they are buried in rock that is covered by a thick ice sheet. It is thought to have large and valuable mineral deposits under the ice. This is because of what has been found in samples taken from the small areas of rock that are exposed, and also from what has been found in South Africa and South America. Up until 180 million years ago, Antarctica was a part of the Gondwanaland super continent, attached to South America, the Southern part of Africa, India and Australia, these continents then drifted apart until they reached their current positions. This leads to a possibility that Antarctica may also share some of the mineral wealth of these continents. Right now on the ice-free areas of Antarctica iron ore, chromium, copper, gold, nickel, platinum, coal and hydrocarbons have been found. The Protocol on Environmental Protection to the Antarctic Treaty, also known as the Madrid Protocol, was signed in 1991 by the signatories to the Antarctic Treaty and became law in January 1998. The Protocol provides for comprehensive protection of the Antarctic environment and associated ecosystems and includes a ban on all commercial mining for at least fifty years (this is up for review in 2041). Current climate change and melting ice in Polar Regions is opening up new opportunities to exploit mineral and oil resources. Even Antarctica's weather, ice and distance from any industrialized areas mean that mineral extraction would be extremely expensive and also extremely dangerous, the depletion of mineral recourses on the Earth can reverse banning of mining in Antarctica in future. There is no question that any resource exploitation in Antarctica will cause

  13. An updated examination of the Luzon Strait transport

    Science.gov (United States)

    Hsin, Yi-Chia; Wu, Chau-Ron; Chao, Shenn-Yu

    2012-03-01

    Despite numerous previous estimates of Luzon Strait transport (LST), we attempt an update using a fine-resolution model. With these improvements, the circulation in and around Luzon Strait shows up rather realistically. Intrusion of a Kuroshio meander into the South China Sea (SCS) is seasonally varying. The LST, especially in the upper ocean, caused by a small difference between the large meander inflow and outflow, is also seasonally varying and subject to large standard deviation. The annual mean LST is estimated to be westward (-4.0 ± 5.1 Sv) along 120.75°E. We have also conducted process of elimination experiments to assess the relative importance of open ocean inflow/outflow, wind stress, and surface heat flux in regulating LST and its seasonality. The East Asian monsoon winds stand out as the predominant forcing. Without it, the upper ocean LST changes from westward to eastward (ranging up to 4 Sv) and, with misaligned seasonality, triggering an inflow from the Mindoro Strait to the SCS to replenish the water mass loss. Discounting monsoon winds, sea level in the Sulu Sea is generally higher because it receives the Indonesian Throughflow before the SCS, which causes an inflow from the Sulu Sea to the SCS. On the other hand, the annual mean wind from the northeast invites outflow from the SCS to the Sulu Sea (or inflow from the Luzon Strait). Weighing the two competing factors together, we see the cessation of northeast monsoon as a condition favorable for the Luzon Strait outflow or the Mindoro Strait inflow.

  14. Potential seaways across West Antarctica

    Science.gov (United States)

    Vaughan, David G.; Barnes, David K. A.; Fretwell, Peter T.; Bingham, Robert G.

    2011-10-01

    The West Antarctic ice sheet (WAIS) has long been considered vulnerable to rapid retreat and today parts are rapidly losing ice. Projection of future change in WAIS is, however, hampered by our poor understanding of past changes, especially during interglacial periods that could be analogs for the future, but which undoubtedly provide an opportunity for testing predictive models. We consider how ice-loss would open seaways across WAIS; these would likely alter Southern Ocean circulation and climate, and would broadly define the de-glacial state, but they may also have left evidence of their existence in the coastal seas they once connected. We show the most likely routes for such seaways, and that a direct seaway between Weddell and Ross seas, which did not pass through the Amundsen Sea sector, is unlikely. Continued ice-loss at present rates would open seaways between Amundsen and Weddell seas (A-W), and Amundsen and Bellingshausen seas (A-B), in around one thousand years. This timescale indicates potential future vulnerability, but also suggests seaways may have opened in recent interglacial periods. We attempt to test this hypothesis using contemporary bryozoan species assemblages around Antarctica, concluding that anomalously high similarity in assemblages in the Weddell and Amundsen seas supports recent migration through A-W. Other authors have suggested opening of seaways last occurred during Marine Isotope Stage 7a (209 ka BP), but we conclude that opening could have occurred in MIS 5e (100 ka BP) when Antarctica was warmer than present and likely contributed to global sea levels higher than today.

  15. The separation of Ceylon from Antarctica

    Science.gov (United States)

    Schreider, Al. A.; Schreider, A. A.; Boiko, A. N.; Kashintsev, G. L.; Evsenko, E. I.

    2011-08-01

    The geometry of the junction between Ceylon and Antarctica during the Gondwanaland breakup is still under discussion. Analysis of the available geological-geophysical materials has allowed the peculiarities of Ceylon separation from Antarctica to be characterized, the new paleogeodynamical reconstruction to be elaborated, and a prognosis of the tectonic structure and mineral resources in the areas of Antarctic coast that were adjacent to Ceylon to be made.

  16. Lagrangian study of temporal changes of a surface flow through the Kamchatka Strait

    CERN Document Server

    Prants, S V; Uleysky, M Yu; Budyansky, M V

    2014-01-01

    Using Lagrangian methods we analyze a 20-year-long estimate of water flux through the Kamchatka Strait in the northern North Pacific based on AVISO velocity field. It sheds new light on the flux pattern and its variability on annual and monthly time scales. Strong seasonality in surface outflow through the strait could be explained by temporal changes in the wind stress over the northern and western Bering Sea slopes. Interannual changes in a surface outflow through the Kamchatka Strait correlate significantly with the Near Strait inflow and Bering Strait outflow. Enhanced westward surface flow of the Alaskan Stream across the $174^\\circ$ E section in the northern North Pacific is accompanied by an increased inflow into the Bering Sea through the Near Strait. In summer, the surface flow pattern in the Kamchatka Strait is determined by passage of anticyclonic and cyclonic mesoscale eddies. The wind stress over the Bering basin in winter - spring is responsible for eddy generation in the region.

  17. A Bibliography of the Physical Oceanography of Straits.

    Science.gov (United States)

    1986-11-01

    Kelley (eds.), Univer- description of currents in the Glebinka Strait in Puck sity of Alaska, Fairbanks, pp. 3-37. Bay (Poland). Oceanografia , Gdansk 5...3742. Archivio di Oceanografia E Limnologia 19:65-82. Whitworth, T. and R. G. Peterson (1985). Volume Waldichuk, M. (1957). Physical oceanography of

  18. Readjustments in U.S. Cross-Taiwan Strait Policy

    Institute of Scientific and Technical Information of China (English)

    Sun Shengliang; Ma Zongshi

    2008-01-01

    Washington had all along followed an ambiguity policy over its possible military intervention in a Taiwan contingency. However, recent years have witnessed readjustments towards "double clarity" of a possible military response in case of a Chinese-initiated use of force and potential inaction in the event of a conflict derived from Taiwanese provocations to change the status quo by seeking de jure independence. In other words, it spells a policy shift toward "dual deterrence," namely to deter the Chinese mainland from using force in seeking national reunification and to deter Taiwan from moving toward de jure independence. To prevent such eventuality, Washington made direct appeal to the Taiwan public to make clear its opposition to Taiwan independence.The reasons behind the readjustments are not far to seek. They reflect shifts in U.S. strategic focus, changes in its China policy, political developments on both sides of the Taiwan Strait and President Bush's personal disgust with former Taiwan leader Chen Shuibian's cunning tricks.However, resumption of Cross-Strait dialogue in the wake of the return to power of the Kuomintang (National Party) through the ballot in March may bring about new worries and possible further readjustments in U.S. cross-strait policy after the November presidential elections. Though uncertainties remain, in the pipeline may be an endeavor to prevent excessive cross-strait warmth and a possible tilt of Taiwan to the Chinese Mainland.

  19. Microbial ecological associations in the surface sediments of Bohai strait

    Science.gov (United States)

    Wang, Bin; Liu, Hongmei; Tang, Haitian; Hu, Xiaoke

    2017-09-01

    Microbial communities play key roles in the marine ecosystem. Despite a few studies on marine microbial communities in deep straits, ecological associations among microbial communities in the sediments of shallow straits have not been fully investigated. The Bohai Strait in northern China (average depth less than 20 m) separates the Bohai Sea from the Yellow Sea and has organic-rich sediments. In this study, in the summer of 2014, six stations across the strait were selected to explore the taxonomic composition of microbial communities and their ecological associations. The four most abundant classes were Gammaproteobacteria, Deltaproteobacteria, Bacilli and Flavobacteriia. Temperature, total carbon, depth, nitrate, fishery breeding and cold water masses influenced the microbial communities, as suggested by representational difference and composition analyses. Network analysis of microbial associations revealed that key families included Flavobacteriaceae, Pirellulaceae and Piscirickettsiaceae. Our findings suggest that the families with high phylogenetic diversity are key populations in the microbial association network that ensure the stability of microbial ecosystems. Our study contributes to a better understanding of microbial ecology in complex hydrological environments.

  20. Iron isotopes in bottom waters from the Bransfield Strait: Implications for deep water Fe supply

    Science.gov (United States)

    Stichel, Torben; Homoky, William; Connelly, Douglas; Klar, Jessica; Mills, Rachel

    2015-04-01

    Iron (Fe) is an important micro-nutrient in the global ocean. However, its low bioavailability due to poor solubility in oxygenated waters, leads to a strongly limiting character of this trace metal as a nutrient. The major sources of Fe to seawater are largely known (i.e. aeolian dust deposition, riverine and groundwater input, seawater-sediment interaction, and hydrothermal vents) but the relative significance of these sources to the marine Fe supply are not yet well quantified. Areas with low atmospheric inputs, such as the Southern Ocean, are severely Fe limited in surface waters. Here, strong upwelling and a deeply penetrating surface mixed layer fuel one of the largest biogeochemical cycles of trace metals in the global ocean. One significant pathway to bottom waters is the benthic flux of trace metals from hydrothermal systems, where Fe can be stabilised in the water column by different dissolved species. For example, benthic fauna, such as tube-worms, may enhance transportation of dissolved trace metals from pore waters through oxic surface layers of sediments into the deep ocean. Concentrations of total dissolvable Fe (DFe) in these bottom waters have been reported to be significantly higher than surrounding seawater (Aquilina et al., 2014). Here we present DFe isotope composition of bottom water from the Hook Ridge, a shallow (~1100m) sediment covered volcanic feature within a rifted margin. On the basis of Fe isotopes we will determine whether Fe is released by non-reductive dissolution from poorly oxygenated sediments via the presence of tubeworms Sclerolinum spec. This will help to evaluate whether benthic fluxes from hydrothermal fields can be a major source of bioavailable Fe to the deep Southern Ocean. References: Aquilina, A., Homoky, W.B., Hawkes, J. A., Lyons, T.W., Mills, R. a., 2014. Hydrothermal sediments are a source of water column Fe and Mn in the Bransfield Strait, Antarctica. Geochim. Cosmochim. Acta 137, 64-80. doi:10.1016/j.gca.2014.04.003

  1. On M2 tidal amplitude enhancement in the Taiwan Strait and its asymmetry in the cross-strait direction

    Science.gov (United States)

    Yu, Haiqing; Yu, Huaming; Ding, Yang; Wang, Lu; Kuang, Liang

    2015-10-01

    Enhanced M2 tidal amplitude in the Taiwan Strait (TS) and asymmetric M2 tidal amplitude in the cross-strait direction have been found and reproduced in numerical simulations. In this study, Finite Volume Coastal Ocean Model (FVCOM) is applied to investigate the mechanisms behind these features. Model results show that the linear interaction of waves from the East China Sea (ECS) and the Luzon Strait (LS) can explain the formation of the co-amplitude and co-phase lines of the M2 tide in the nodal point area, while the waves from the ECS dominate the tidal motion in the TS according to a basic linear wave superposition. Model simulation also show that wave reflection and transition occur when the M2 tidal waves from the ECS propagate through the TS and encounter an sharply deepened topography. The interaction of these induced reflection waves and the incident waves from the ECS is the main cause for the enhanced M2 tidal amplitude in the TS. The distribution of the sharply deepened topography, rather than the Coriolis effect, is the main reason for the asymmetry of the M2 tidal amplitude in the cross-strait direction in the TS. These findings provide some references for tidal dynamics in other areas, especially where long waves propagate through the shallow water to the deep sea.

  2. Influence of a narrow strait connecting a large ocean and a small sea on magnetotelluric data: Gibraltar Strait

    Science.gov (United States)

    González-Castillo, Lourdes; Junge, Andreas; Galindo-Zaldívar, Jesús; Löwer, Alexander

    2015-11-01

    Long period magnetotelluric (LMT) data are generally used as the prime tool to shed light on the conductivity of the deep crust and upper mantle structure. Naturally, LMT data are sensitive to the influence of highly conductive bodies even at far distances. Sea water constitutes the main widespread electrical conductor at shallow levels of the Earth's crust. Its low resistivity values, around 0.25 Ωm, contrast sharply with most geological structures of solid earth. Consequently, the presence of irregular continental borders and varying bathymetries significantly influences LMT parameter, such as phase tensor and tipper vectors. This effect is especially important in areas where large and small oceans are connected by narrow gateways. The Gibraltar Strait (southern Spain) connects the vast Atlantic Ocean with the irregular and relatively small Mediterranean Sea. Several 3D models have been developed in the region nearby the Strait, some featuring a roughly simplified geological structure, to show the influence of seawater on tipper and phase tensor. Here, detailed bathymetry (General Bathymetric Chart of the Oceans, GEBCO) including the coastline is considered in a model that enables us to analyze the influence of the Strait of Gibraltar on LMT data. We stress the significance of the Sea for LMT data interpretation and the development of 3D conductivity models, especially in regions involving complex coastline geometries and bathymetry near narrow straits. Forward modeling studies are essential to accurately appraise the sea influence, which may mask 3D geological structures.

  3. Space analogue studies in Antarctica

    Science.gov (United States)

    Lugg, D.; Shepanek, M.

    1999-01-01

    Medical research has been carried out on the Australian National Antarctic Research Expeditions (ANARE) for 50 years. As an extension of this program collaborative Australian/United States research on immunology, microbiology, psychology and remote medicine has produced important data and insight on how humans adapt to the stress of extreme isolation, confinement and the harsh environment of Antarctica. An outstanding analogue for the isolation and confinement of space missions (especially planetary outposts), ANARE has been used as an international research platform by Australia and the United States since 1993. Collaborative research has demonstrated a lowered responsiveness of the immune system under the isolation and confinement of Antarctic winter-over; a reduction of almost 50% in T cell proliferation to mitogen phytohaemogglutinin, as well as changes in latent herpesvirus states and the expansion of the polyclonal latent Epstein-Barr virus infected B cell populations. Although no clinically significant disease has been found to result from these immune changes, research is currently assessing the effects of psychological factors on the immune system. This and associated research performed to date and its relevance to both organisations is discussed, and comment made on possible extensions to the program in both medical and other fields.

  4. Space analogue studies in Antarctica

    Science.gov (United States)

    Lugg, D.; Shepanek, M.

    1999-01-01

    Medical research has been carried out on the Australian National Antarctic Research Expeditions (ANARE) for 50 years. As an extension of this program collaborative Australian/United States research on immunology, microbiology, psychology and remote medicine has produced important data and insight on how humans adapt to the stress of extreme isolation, confinement and the harsh environment of Antarctica. An outstanding analogue for the isolation and confinement of space missions (especially planetary outposts), ANARE has been used as an international research platform by Australia and the United States since 1993. Collaborative research has demonstrated a lowered responsiveness of the immune system under the isolation and confinement of Antarctic winter-over; a reduction of almost 50% in T cell proliferation to mitogen phytohaemogglutinin, as well as changes in latent herpesvirus states and the expansion of the polyclonal latent Epstein-Barr virus infected B cell populations. Although no clinically significant disease has been found to result from these immune changes, research is currently assessing the effects of psychological factors on the immune system. This and associated research performed to date and its relevance to both organisations is discussed, and comment made on possible extensions to the program in both medical and other fields.

  5. The Landsat Image Mosaic of Antarctica (LIMA): A Cutting-Edge Way for Students and Teachers to Learn about Antarctica

    Science.gov (United States)

    Campbell, Brian; Bindschadler, Robert

    2009-01-01

    By studying Antarctica via satellite and through ground-truthing research, we can learn where the ice is melting and why. The Landsat Image Mosaic of Antarctica (LIMA), a new and cutting-edge way for scientists, researchers, educators, students, and the public to look at Antarctica, supports this research and allows for unprecedented views of our…

  6. Variation of the cold intermediate water in the Black Sea exit of the Strait of Istanbul (Bosphorus and its transfer through the strait

    Directory of Open Access Journals (Sweden)

    Huseyin Yuce

    2012-04-01

    Full Text Available The cold intermediate water (CIW, T < 8°C entering the Strait of Istanbul and its variation along the strait have been studied by using monthly conductivity-temperature-depth (CTDdata sets collected during the period from 1996 to 2000. In the northern exit of the strait, CIW is located between the seasonal thermocline and Mediterranean water originating from the lowerlayer of the Sea of Marmara. The thickness of CIW decreases fromApril to October. In the Strait of Istanbul, CIW is observedas a layer of temperature < 14$^{circ}$C. The thickness of thismodified cold intermediate water flowing southwards with the upper layer decreases, while its temperature increases along thestrait due to mixing with adjacent water. In the southern exit of the strait, the modified cold intermediate water is observed during the period from May to October. If CIW exists in the Black Sea exit region of the strait, modified cold water is found inthe Marmara exit region during the same period. The distribution of CIW in the Strait of Istanbul contributes to our understanding of the dynamics of the strait, especially in the summer months.

  7. Human genetic differentiation across the Strait of Gibraltar

    Directory of Open Access Journals (Sweden)

    Sanchez-Mazas Alicia

    2010-08-01

    Full Text Available Abstract Background The Strait of Gibraltar is a crucial area in the settlement history of modern humans because it represents a possible connection between Africa and Europe. So far, genetic data were inconclusive about the fact that this strait constitutes a barrier to gene flow, as previous results were highly variable depending on the genetic locus studied. The present study evaluates the impact of the Gibraltar region in reducing gene flow between populations from North-Western Africa and South-Western Europe, by comparing formally various genetic loci. First, we compute several statistics of population differentiation. Then, we use an original simulation approach in order to infer the most probable evolutionary scenario for the settlement of the area, taking into account the effects of both demography and natural selection at some loci. Results We show that the genetic patterns observed today in the region of the Strait of Gibraltar may reflect an ancient population genetic structure which has not been completely erased by more recent events such as Neolithic migrations. Moreover, the differences observed among the loci (i.e. a strong genetic boundary revealed by the Y-chromosome polymorphism and, at the other extreme, no genetic differentiation revealed by HLA-DRB1 variation across the strait suggest specific evolutionary histories like sex-mediated migration and natural selection. By considering a model of balancing selection for HLA-DRB1, we here estimate a coefficient of selection of 2.2% for this locus (although weaker in Europe than in Africa, which is in line with what was estimated from synonymous versus non-synonymous substitution rates. Selection at this marker thus appears strong enough to leave a signature not only at the DNA level, but also at the population level where drift and migration processes were certainly relevant. Conclusions Our multi-loci approach using both descriptive analyses and Bayesian inferences lead to

  8. Acting Antarctica: science on stage

    Science.gov (United States)

    Ciceri, Piera; Tizzoni, Paola; Pierro, Luigia

    2016-04-01

    Key-words: Polar science, Earth science, Theatre, Hands on activities The legendary Antarctic Expedition of sir E. Shackleton and his crew of 27 aboard the Endurance (1914/16) trapped in the Antarctic ice has become the starting point to learn about Polar Science and Climate Change. While the students were involved into this incredible adventure by the astonishing images of the Australian photographer Frank Hurley (who joined the crew), they discovered the world in which this story happened. Students were then involved in hands-on activities and role plays and have become the writers of the play "Uomini a scienza ai confini del mondo". They act the story of Shackelton's expedition and they tell at the same time to the audience about ice pack, ice cores and their role in understanding the past of the climate, physical and geographical characteristic of polar regions, thermal phenomena related to adaptations of polar animals, solar radiation at different latitude, day/night duration. The theater was the place to "stage" some scientific experiments and to explain the current research carried out in polar regions and their importance in climate change studies and to stress some similarities between Antarctica and space. The project was carried out from teachers of science, letters and geography and was born in collaboration with the "Piccolo Teatro di Milano" and the association "Science Under 18" with the support of a professional actor and director and was played for other schools at "EXPO 2015" in Milano (Italy). In our opinion drama activities improve reading comprehension, and both verbal and non-verbal communication skills. To be able to write and to act, students need a deep understanding of contents. Arts, including theatre, are a good key to involve emotionally students. To have an audience different from their own teachers and classmates offers a real task and the opportunity to play and let grow real skills.

  9. Management and control of pollution in Inner Johore Strait.

    Science.gov (United States)

    Koh, H L; Lim, P E; Midun, Z

    1991-10-01

    Coastal waters in South Johore, Malaysia are polluted to various degrees. The major pollution sources are domestric wastes from human settlements, agro-based wastes from palm oil mills and rubber processing factories, industrial effluents from industrial estates and discharges from animal farms. These pollution problems have adversely affected resources such as fisheries, recreational potential as well as the general aesthetic quality of the coastal environment particularly the Inner Johore Strait. Hence proper management and control measures are urgently needed to protect and further enhance the water quality to ensure environmentally sustainable development. This study examines various management options to control the pollution in the Inner Johore Strait. The options involve partial opening as well as complete removal of the Causeway to improve the tidal flow for more effective dilution and dispersion of pollutants. Computer simulation models are used to assess the impacts of the proposed options.

  10. Structure and Variability of Internal Tides in Luzon Strait

    Science.gov (United States)

    2016-09-14

    Sponsor ON R. (I) .2- 2,6— approval obtained yes X no Title of Parer or Presentation Structure and Variability of Internal Tides in Luzon Strait...ision, Div v Author, Code HQ-NRL 55118 (Rev. 12-98) (e) THIS FORM CANCELS AND SUPERSEDES ALL PREVIOUS VERSIONS Structure and Variability of Internal ... internal tides that radiate westward into the South China Sea and eastward into the western Pacific. Intrusions of the Kuroshio and strong mesoscale

  11. The bimodality of the Luzon Strait deep water

    Institute of Scientific and Technical Information of China (English)

    WU Qingsong; ZHAO Jianru; ZHANG Junbiao; SHI Weiyong; LIU Chunqiu

    2014-01-01

    Combined conductivity-temperature-depth (CTD) casts and Argo profiles, 3 086 historical hydrocasts were used to quantify the water column characteristics in the northern South China Sea (SCS) and its adjacent waters. Based on a two-dimensional“gravest empirical mode”(GEM), a gravitational potential (׋, a verti-cally integrated variable) was used as proxy for the vertical temperature profiles TG(p,׋).׋integrated from 8 MPa to the surface shows a close relationship with the temperature, except in the deep layer greater than 15 MPa, which was caused by the bimodal deep water in the region. The GEM temperature profiles successfully revealed the bimodality of the Luzon Strait deep water, that disparate hydrophic vertical profiles can pro-duce distinct specific volume anomaly (į) in the SCS and the western Philippine Sea (WPS), but failed in the Luzon Strait, where different temperature profiles may produce a sameį. A significant temperature diver-gence between the SCS water and the WPS water confirmed that the bimodal structure is strong. The deep-water bifurcation starts at about 15 MPa, and gets stronger with increasing depth . As the only deep channel connecting the bimodal-structure waters, water column characteristics in the Luzon Strait is in between, but much closer to the SCS water because of its better connectivity with the SCS. A bimodal temperature structure below 15 MPa reveals that there was a persistent baroclinic pressure gradient driving flow through the Luzon Strait. A volume flux predicted through the Bashi Channel with the hydraulic theory yields a value of 5.62×106 m3/s using all available profiles upstream and downstream of the overflow region, and 4.03×106 and 2.70×106 m3/s by exclusively using the profiles collected during spring and summer, respectively. No volume flux was calculated during autumn and winter because profiles are only available for the upstream of the Bashi Channel during the corresponding period.

  12. Shared medical appointments for Aboriginal and Torres Strait Islander men.

    Science.gov (United States)

    Stevens, John A; Dixon, John; Binns, Andrew; Morgan, Bob; Richardson, Jeff; Egger, Garry

    2016-06-01

    Aboriginal and Torres Strait Islander health is generally the worst of any population group in Australia. Inaccessibility to health services is one possible cause of this. Shared medical appointments (SMAs) appear to be a culturally competent and appropriate way of improving access to, and the quality of, primary healthcare services for Aboriginal and Torres Strait Islander peoples. The objective of this article is to assess the acceptability and appropriateness of SMAs as an adjunct process in primary care for Aboriginal and Torres Strait Islander men. As part of a broader study on SMAs, three SMA sessions were delivered at an Aboriginal men's health centre in northern New South Wales. One-day training sessions in SMA facilitation were also provided to two groups of 12-14 Aboriginal health workers (AHWs). Mixed methods were used to assess patient and provider satisfaction, subjective outcomes, and operational procedures in the SMA groups, as well as interest in the SMA process by AHWs. Satisfaction with SMAs among Aboriginal men was unanimously positive, with the numbers in the group increasing over time. Patients most enjoyed the 'yarn up' nature of SMAs with peer support, which reduced the 'scary' and culturally 'unnatural' nature of one-on-one consultations with a general practitioner (GP). AHWs who were trained to a level to conduct SMAs saw this as an effective way of improving cultural competence in, and accessibility of, their various Aboriginal health services. The results, though not generalisable, suggest that SMAs may offer a culturally safe and appropriate tool to enhance Aboriginal and Torres Strait Islander peoples' access to primary care.

  13. Laboratory Modeling of Internal Wave Generation in Straits

    Science.gov (United States)

    2014-06-13

    Peacock 2010). 3. The suitability of the double ridge configuration of the Luzon Strait to give rise to resonant forcing of the semi-diurnal...Figure 6. 6 Figure 6: PIV visualization of the magnitude of the in-plane velocity of the 3D conical internal wave field generated by a...Visualization of the conical 3D internal wave field generated by an oscillating sphere using stereo-PIV, Experiments in Fluids, 54, 1454. Mathur

  14. On summer stratification and tidal mixing in the Taiwan Strait

    Institute of Scientific and Technical Information of China (English)

    Jia ZHU; Jianyu HU; Zhiyu LIU

    2013-01-01

    On continental shelves,a front that separates the sea into well-mixed and stratified zones is usually formed in warm seasons due to spatial variations of tidal mixing.In this paper,using eight years of in situ hydrographic observations,satellite images of sea surface temperature (SST) and chlorophyll-a (Chl-a) concentration,and results of a tidal model,we investigate summer stratification in the Taiwan Strait and its dependence on tidal mixing,upwelling,and river diluted water plumes.In most regions of the strait the dominant role of tidal mixing in determining the thermohaline structure is confirmed by the correlation between the two; there are some regions,however,where thermohaline structttre varies in different ways owing to significant influences ofupwelling and river diluted water plumes.The well-mixed regions are mainly distributed on the Taiwan Bank and in the offshore regions offthe Dongshan Island,Nanao Island,and Pingtan Island,while the northern and central Taiwan Strait and the region south of the Taiwan Bank are stratified.The critical Simpson-Hunter parameter for the region is estimated to be 1.78.

  15. Large sea ice outflow into the Nares Strait in 2007

    DEFF Research Database (Denmark)

    Kwok, R.; Pedersen, L.T.; Gudmandsen, Preben

    2010-01-01

    ice in the 13-year record between 1997 and 2009. The 2007 area and volume outflows of 87 x 10(3) km(2) and 254 km(3) are more than twice their 13-year means. This contributes to the recent loss of the thick, multiyear Arctic sea ice and represents similar to 10% of our estimates of the mean ice export......Sea ice flux through the Nares Strait is most active during the fall and early winter, ceases in mid- to late winter after the formation of ice arches along the strait, and re-commences after breakup in summer. In 2007, ice arches failed to form. This resulted in the highest outflow of Arctic sea...... at Fram Strait. Clearly, the ice arches control Arctic sea ice outflow. The duration of unobstructed flow explains more than 84% of the variance in the annual area flux. In our record, seasonal stoppages are always associated with the formation of an arch near the same location in the southern Kane Basin...

  16. Formation of wind-driven ice bridges in narrow straits

    Science.gov (United States)

    Rallabandi, Bhargav; Zheng, Zhong; Winton, Michael; Stone, Howard A.

    2016-11-01

    An ice bridge is a static arch made of tightly packed ice that can be formed when sea ice flows through a narrow strait between landmasses. The formation of a stable ice arch prevents the further flow of sea ice into warmer oceans, and therefore plays an important role in the regulation of the local climate and ecology and to an extent, the mass balance of Arctic ice. While ice bridges are a seasonal phenomenon in many parts of the Canadian Archipelago, the process of their formation and breakup is poorly understood. Using thin-layer theory along with dynamic sea ice models widely used in climate modeling, we develop a reduced-order description of wind-driven ice bridge formation in long, narrow straits. Our theory predicts a critical static condition for arrested flow that involves the ice properties (thickness and compactness), the geometry of the channel, and the magnitude of the wind stress. Further, we show that in a channel of varying shape and under a constant wind stress, a spatially uniform ice field evolves towards a steady state with discontinuities in its properties, consistent with observed mechanisms of ice bridge formation. The reduced-order model thus provides a predictive tool for the flow and stoppage of sea ice in straits.

  17. Tidal energy resource complexity in a large strait: The Karori Rip, Cook Strait

    Science.gov (United States)

    Stevens, C. L.; Smith, M. J.; Grant, B.; Stewart, C. L.; Divett, T.

    2012-02-01

    Successful extraction of tidal stream energy will require a good understanding of flow at a range of scales, including those relating to average energy, variability in energy supply and fatigue. Current and turbulence measurements from the Karori Rip area of Cook Strait, the prime focal region of open-water tidal stream electricity generation in New Zealand, are described. A key issue is that a significant portion of the energy is contained in waters deeper than normally considered for energy extraction. Here we compare shallow and deep sites. Velocity data were derived from acoustic Doppler current profiler moorings, as well as spatial surveys and show flow magnitudes reaching 3.4 m s -1 in the shallow regions. The maximum speeds in both shallow and deep sites were typically located in the upper part of the measured water column although moored acoustic Doppler current profiler (ADCP) observations showed some complexity in this regard. Benthic boundary-layers were resolved in the bottom ˜20 m of the water column. Measured turbulent kinetic energy dissipation rates ɛ exceeded 10 -5 m 2 s -3 and estimated maximum ɛ is a factor of 10 greater. This was not distributed evenly through the water column, with stratification and velocity shear clearly persisting, especially around the turn of the tide. The implications for tidal stream energy are that (i) there is sufficient energy resource in the region for a moderate sized array of turbines, (ii) the vertical variability in the flow speed suggests turbines that can operate near the surface would be more effective at accessing the resource, (iii) stratification may persist and influence the scales of turbulence and (iv) wave-current interaction effects will influence any near-surface structure as well as vessel operations.

  18. ULF fluctuations at Terra Nova Bay (Antarctica

    Directory of Open Access Journals (Sweden)

    A. Meloni

    2000-06-01

    Full Text Available ULF geomagnetic field measurements in Antarctica are a very important tool for better understanding the dynamics of the Earth’s magnetosphere and its response to the variable solar wind conditions. We review the results obtained in the last few years at the Italian observatory at Terra Nova Bay

  19. Sterile soil from Antarctica: organic analysis.

    Science.gov (United States)

    Horowitz, N H; Bauman, A J; Cameron, R E; Geiger, P J; Hubbard, J S; Shulman, G P; Simmonds, P G; Westberg, K

    1969-05-30

    Soils from the dry-valley region of Antarctica can be sterile by the usual microbiological criteria and yet contain significant amounts of organic carbon. Examination of one such soil shows that the organic material is finely divided anthracite coal. These findings have significant implications for the biological exploration of Mars.

  20. Antarctica: Is It More Than Just Ice?

    Science.gov (United States)

    Johnson, Cheryl; Gutierrez, Melida

    2009-01-01

    The authors introduced polar science in a fourth-grade classroom by means of 3 hands-on activities that addressed (1) the melting of glaciers and ice, (2) the differences between the North and the South Pole, and (3) the geography and landforms of Antarctica. An assessment 4 months after the original activity showed that students remembered the…

  1. Antarctica: Is It More Than Just Ice?

    Science.gov (United States)

    Johnson, Cheryl; Gutierrez, Melida

    2009-01-01

    The authors introduced polar science in a fourth-grade classroom by means of 3 hands-on activities that addressed (1) the melting of glaciers and ice, (2) the differences between the North and the South Pole, and (3) the geography and landforms of Antarctica. An assessment 4 months after the original activity showed that students remembered the…

  2. First airborne transient em survey in antarctica

    DEFF Research Database (Denmark)

    Auken, Esben; Mikucki, J. J.; Sørensen, Kurt Ingvard K.I.

    2012-01-01

    A first airborne transient electromagnetic survey was flown in Antarctica in December 2011 with the SkyTEM system. This transient airborne EM system has been optimized in Denmark for almost ten years and was specially designed for ground water mapping. The SkyTEM tool is ideal for mapping...

  3. Read--and Walk--to Antarctica

    Science.gov (United States)

    Harr, Natalie; Doneyko, Kathleen; Lee, Richard E., Jr.

    2012-01-01

    The students at Crestwood Primary School proved that they have what it takes to exercise their bodies and their minds. In an effort to support their teacher's scientific expedition to Antarctica, students from kindergarten to second grade pledged to read books and do physical activity that equated to the 12,900 km (8,000-mile) journey to the…

  4. Ostracoda from Vestfold Hill lake terraces, Antarctica

    Digital Repository Service at National Institute of Oceanography (India)

    Setty, M.G.A.P.

    Six species of ostracodes are recorded from two transects of terraces of Deep Lake, Vestfold Hills, Antarctica. Two species (@iXesteleberis@@ sp. and @iBradleya dictyon@@) range from Cretaceous to Recent, @iPoseidonamicus aff. P. major@@ ranges from...

  5. The Very Late Eocene Opening of Fram Strait between the Arctic Ocean and the Nordic Seas: Linkages with the Popigai Impact

    Science.gov (United States)

    Hillaire-Marcel, C.; Poirier, A.

    2013-12-01

    ~ 10^8 megatons, resulting in a potential seismic event in the Fram Strait area with a magnitude > 10, likely to have resulted in major faulting in the area, thus possibly leading to the opening of the Strait. This very late Eocene opening of Fram Strait, would suggest a potential role of the Arctic basin in the inception of the Atlantic Meridional Overturning Circulation. With this new chronology, the entry of the Earth in the "cold house" system of the Early Oligocene, and the early indices for ice-rafting, might have being nearly synchronous in the Arctic and the circum-Antarctica.

  6. Xenarcturus spinulosus Sheppard, 1957 (Crustacea, Isopoda, Valvifera): Redescription of a specimen from the Strait of Magellan

    NARCIS (Netherlands)

    Park, Ja-Yang

    1995-01-01

    A redescription of a primitive arcturid species, Xenarcturus spinulosus, from the Strait of Magellan is presented with discussion of the systematic position of the monotypical subfamily Xenarcturinae.

  7. A Strait Comparison: Lessons Learned from the 1915 Dardanelles Campaign in the Context of a Strait of Hormuz Closure Event

    Science.gov (United States)

    2011-09-01

    the Dardanelles through the lens of such an event, distill a number of recommendations for the United States and its Coalition partners relevant to...knots going against the current of the Straits, were to steam past the minefields, turn, and sweep them coming back downstream. Seven trawlers set...principle, be increased to 11 MBD using drag -reducing agents [23]. 37 Saudi Arabia and the UAE, and Iran has a large, restive population that, in

  8. Recirculation in the Fram Strait and transports of water in and north of the Fram Strait derived from CTD data

    Directory of Open Access Journals (Sweden)

    M. Marnela

    2013-05-01

    Full Text Available The volume, heat and freshwater transports in the Fram Strait are estimated from geostrophic computations based on summer hydrographic data from 1984, 1997, 2002 and 2004. In these years, in addition to the usually sampled section along 79° N, a section between Greenland and Svalbard was sampled further north. Quasi-closed boxes bounded by the two sections and Greenland and Svalbard can then be formed. Applying conservation constraints on these boxes provides barotropic reference velocities. The net volume flux is southward and varies between 2 and 4 Sv. The recirculation of Atlantic water is about 2 Sv. Heat is lost to the atmosphere and the heat loss from the area between the sections averaged over the four years is about 10 TW. The net heat (temperature transport is 20 TW northward into the Arctic Ocean, with large interannual differences. The mean net freshwater added between the sections is 40 mSv and the mean freshwater transport southward across 79° N is less than 60 mSv, indicating that most of the liquid freshwater leaving the Arctic Ocean through Fram Strait in summer is derived from sea ice melt in the northern vicinity of the strait. In 1997, 2001 and 2003 meridional sections along 0° longitude were sampled and in 2003 two smaller boxes can be formed, and the recirculation of Atlantic water in the strait is estimated by geostrophic computations and continuity constraints. The recirculation is weaker close to 80° N than close to 78° N, indicating that the recirculation is mainly confined to the south of 80° N. This is supported by the observations in 1997 and 2001, when only the northern part of the meridional section, from 79° N to 80° N, can be computed with the constraints applied. The recirculation is found strongest close to 79° N.

  9. Recirculation in the Fram Strait and transports of water in and north of the Fram Strait derived from CTD data

    Directory of Open Access Journals (Sweden)

    M. Marnela

    2012-10-01

    Full Text Available The volume, heat and freshwater transports in the Fram Strait are estimated from geostrophic computations based on summer hydrographical data from 1984, 1997, 2002 and 2004. In these years, in addition to the usually sampled section along 79° N, a section between Greenland and Svalbard was sampled further north. Quasi-closed boxes bounded by the two sections and Greenland and Svalbard can then be formed and conservation constraints applied on the boxes. The net volume flux is southward and varies between 2 and 4 Sv. The recirculation of Atlantic water is about 2 Sv. Heat is lost to the atmosphere and the heat loss averaged for the four boxes is about 10 TW and the net heat (temperature transport is 20 TW northward into the Arctic Ocean, with large interannual differences. The mean net freshwater added between the sections is 40 mSv and the mean freshwater transport southward across 79° N is less than 60 mSv, indicating that most of the liquid freshwater leaving the Arctic Ocean through Fram Strait in summer derives from sea ice melt in the northern vicinity of the strait.

    In 1997, 2001 and 2003 meridional sections along 0° longitude were sampled and in 2003 two smaller boxes can be formed, and the recirculation of Atlantic water in the strait is estimated by geostrophic computations and continuity constraints. The recirculation is weaker close to 80° N than close to 78° N, indicating that the recirculation is mainly confined to south of 80° N. This is supported by the observations in 1997 and 2001, when only the northern part of the meridional section, from 79° N to 80° N, can be computed with the constraints applied. The recirculation is found strongest close to 79° N.

  10. Glacimarine sedimentation in Petermann Fjord and Nares Strait, NW Greenland

    Science.gov (United States)

    Hogan, Kelly; Jakobsson, Martin; Mayer, Larry; Mix, Alan; Nielsen, Tove; Kamla, Elina; Reilly, Brendan; Heirman, Katrina An; Stranne, Christian; Mohammed, Rezwan; Eriksson, Bjorn; Jerram, Kevin

    2017-04-01

    Here we build on preliminary results from 6500 line-km of high-resolution chirp sub-bottom profiles (2-7 kHz) acquired in Petermann Fjord and Nares Strait during the Petermann 2015 Expedition of the Swedish icebreaker Oden. We map the unlithified sediment cover in Peterman Fjord, which consists of up to 3 conformable "drape" units and calculate volumes of this assumed "post-glacial" fill. In Nares Strait we have mapped sediment volumes in local basins just beyond the sill at the Petermann Fjord-mouth: do these sediments represent material flushed out from the grounding zone of Petermann Glacier when it was grounded at the sill? In this vein, and interestingly, some of the thickest sediments that we observe are found close to a grounding-zone wedge (GZW) in Nares Strait that represents a former grounding zone of ice retreating southwards through the strait. We also map conformable units across Nares Strait and consider the similarities between these and the sediment units in the fjord. Do the strong reflections between the units represent the same climatic, oceanographic or process-shift both inside and outside the fjord? We also aim to tie our new acoustic stratigraphy to sediment-core data (lithofacies, dates) and, therefore, to comment on the age of the mapped sediment units and present ideas on the glacimarine flux of material to the Petermann-Nares system. Primary sediment delivery to the seafloor in this environment is thought to be predominantly through sedimentation from meltwater plumes but also of iceberg-rafted debris (IRD). However, sediment redeposition by slope failures on a variety of scales also occurs and has focussed sediments into discrete basins where the seafloor is rugged. This work - which aims to relate past sediment, meltwater and iceberg fluxes to changes in climate - will help us to identify how the system has responded to a past global warming event, namely the last deglaciation. This is particularly relevant in light of the recent

  11. Hydrological, plankton and pigment observations in the Makassar Strait, Madura Strait and Eastern Java Sea by the R.V. Samudera, April 16 to May 19, 1975 (NODC Accession 7700306)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Zooplankton and chemical data were collected using net and bottle casts from the R.V. SAMUDERA in the Makassar Strait, Madura Strait and Eastern Java Sea from 16...

  12. Sexual maturity cycle and spawning of Greenland halibut Reinhardtius hippoglossoides in the Davis Strait

    DEFF Research Database (Denmark)

    Gundersen, A. C.; Stenberg, Claus; Fossen, I.

    2010-01-01

    Female sexual maturation cycle and the main spawning time of Greenland halibut Reinhardtius hippoglossoides in the Davis Strait were studied through regularly collected samples during 1 year starting in spring 2003. Samples were collected from the southern slope of the Davis Strait Ridge between ...

  13. 33 CFR 117.169 - Mare Island Strait and the Napa River.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Mare Island Strait and the Napa River. 117.169 Section 117.169 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND... Strait and the Napa River. (a) The draw of the Mare Island Drawbridge, mile 2.8, at Vallejo shall open...

  14. Improving the Participation and Engagement of Aboriginal and Torres Strait Islander Students in Business Education

    Science.gov (United States)

    Dang, Thi Kim Anh; Vitartas, Peter; Ambrose, Kurt; Millar, Hayley

    2016-01-01

    Most Australian universities have among their goals to increase the number of Aboriginal and Torres Strait Islander students at their institutions. In the Australian higher education context, Aboriginal and Torres Strait Islander students are seriously under-represented, particularly in business education compared to other disciplines. An…

  15. The Holocene History of Nares Strait: Transition from Glacial Bay to Arctic-Atlantic Throughflow

    DEFF Research Database (Denmark)

    Jennings, Anne; Sheldon, Christina; Cronin, Thomas

    2011-01-01

    Retreat of glacier ice from Nares Strait and other straits in the Canadian Arctic Archipelago after the end of the last Ice Age initiated an important connection between the Arctic and the North Atlantic Oceans, allowing development of modern ocean circulation in Baffin Bay and the Labrador Sea. ...

  16. The oldest plesiosaur (Reptilia, Sauropterygia from Antarctica

    Directory of Open Access Journals (Sweden)

    Alexander Wilhelm Armin Kellner

    2011-06-01

    Full Text Available Antarctic plesiosaurs are known from the Upper Cretaceous López de Bertodano and Snow Hill Island formations (Campanian to upper Maastrichtian, which crop out within the James Ross Basin region of the Antarctic Peninsula. Here we describe the first plesiosaur fossils from the Lachman Crags Member of the Santa Marta Formation, north-western James Ross Island. This material constitutes the stratigraphically oldest plesiosaur occurrence presently known from Antarctica, extending the occurrence of plesiosaurians in this continent back to Santonian times (86.3–83.5 Mya. Furthermore, MN 7163-V represents the first plesiosaur from this region not referable to the Elasmosauridae nor Aristonectes, indicating a greater diversity of this group of aquatic reptiles in Antarctica than previously suspected.

  17. 75 FR 70818 - Traffic Separation Schemes: In the Strait of Juan de Fuca and Its Approaches; in Puget Sound and...

    Science.gov (United States)

    2010-11-19

    ... sight-obscured, right-angle turn in the presence of strong currents and numerous small craft. 7... Fuca and Its Approaches; in Puget Sound and Its Approaches; and in Haro Strait, Boundary Pass, and the... Strait of Juan de Fuca and its approaches, in Puget Sound and its approaches, and in Haro Strait...

  18. Taiwan’s Security Calculus of Cross-­Strait Migration

    Directory of Open Access Journals (Sweden)

    Ching Chang

    2015-08-01

    Full Text Available Migration across the Taiwan Strait is relatively insignificant by its scale but it is indeed indisputably politically sensitive. Given the long-term political separation and military rivalry across the Taiwan Strait in the past six decades while both sides of the Taiwan Strait nevertheless intensively engaged each other economically, commercially and culturally, a social trend of cross-Strait migration inevitably results. There are various interpretations on such a demographic development which has raised security concerns, which are in turn creating a biased judiciary arrangement on the migration activities. What are the factors behind the security calculus of cross-Strait migration? How can the security calculus justify its arguments and subsequently maintain unequal treatments with respect to cross-Strait immigrants? Are the rationales for maintaining a tight grip on cross-Strait migration in line with the political ideal proclaimed by the political factions in Taiwan still sensible? What is the potential for the trend of cross-Strait migration affecting the security calculus in the future? On the other hand, for the migration from Taiwan to Mainland China, how influential can it be on the security decision-making process of the Beijing leadership? Is there any impact possibly caused by cross-Strait migration – and is it essentially overstated? Or alternatively, is the overstated influence potentially caused by cross-Strait migration an intentionally staged political myth? What are the substantial impacts actually ever achieved by cross-Strait migration on the security dimension? What is the self-fulfilled conviction of cross-Strait migration? For all the inquiries noted above, the author of this paper would like to scrutinize the truth and separate it from numerous myths ever advocated by the different factions in Taiwan politics. A sound and neutral judgment to tell the exact influences likely enacted by cross-Strait migration would

  19. 南极海-陆界面营养物质流动和磷循环%Nutrient flow and phosphorus cycle in sea-land interface in the Antarctica

    Institute of Scientific and Technical Information of China (English)

    秦先燕; 黄涛; 孙立广

    2013-01-01

    南极大陆气候严寒、营养贫瘠,企鹅、海豹等生物能传递海洋中的营养物质到陆地,这些营养物质是维系南极无冰区生态系统的基础.本文首先阐述了海洋向南极无冰区输入营养物质的方式,重点介绍了生物方式输入的营养物质对无冰区生态系统组成、结构和功能的影响,以及无冰区向近海输入营养物质的方式及其影响.然后,以西南极法尔兹半岛为例,对企鹅、海豹传输的营养物质磷在陆地、淡水生态系统中的记录进行了分析,讨论了南极近海磷的生物地球化学循环及其机理,估算了磷循环通量.结果表明,南极阿德雷岛磷的外来营养源包括物理输入、生物输入和大气沉降输入3种,其中,生物输入(企鹅粪)占94.34% ~ 99.74%,在近海磷循环中起着关键作用.%The Antarctica is very cold and infertile, where the organisms such as seals and pen-guins can transfer nutrients from sea to land, and these nutrients are crucial to support the eco-systems in the ice-free areas of the Antarctica. This paper reviewed the ways by which the nutri-ents were transferred from the sea to the ice-free areas of the Antarctica, with the focus on the effects of the nutrients transferred by the organisms on the composition, structure, and function of the ecosystems in the ice-free areas, as well as the pathways of nutrient translocation from the ice-free areas to the sea and their impacts on the marine ecosystems. Taking the Fildes Peninsula in West Antarctica as an example, the data of the phosphorus transferred by penguins and seals to the terrestrial and freshwater ecosystems were compiled and analyzed, the mechanisms of the phosphorus biogeochemical cycle in the Antarctica were discussed, and the flux of the phosphorus was estimated. Our results indicated that in the Ardley Island of the Antarctica, there were three ways of foreign phosphorus input, including physical transport, bio-transport, and

  20. Observed Volume Fluxes and Mixing in the Dardanelles Strait

    Science.gov (United States)

    2013-10-04

    Laboratory (NRL) and the NATO Undersea Research Center ( NURC ; cur- rently known as the NATO Center for Maritime Research and Experimentation, CMRE...Dardanelles Strait as a part of the TSS08 ( NURC project) and EPOS (NRL project) programs. The deployment began at the end of August 2008 and ended at...previously known as the NATO NURC ) who sup- ported and helped to organi/e and fund cruises to the TSS on the R.’V Alli- ance. We arc also grateful for

  1. How can GPs drive software changes to improve healthcare for Aboriginal and Torres Strait Islanders peoples?

    Science.gov (United States)

    Kehoe, Helen

    2017-01-01

    Changes to the software used in general practice could improve the collection of the Aboriginal and Torres Strait Islander status of all patients, and boost access to healthcare measures specifically for Aboriginal and Torres Strait Islander peoples provided directly or indirectly by general practitioners (GPs). Despite longstanding calls for improvements to general practice software to better support Aboriginal and Torres Strait Islander health, little change has been made. The aim of this article is to promote software improvements by identifying desirable software attributes and encouraging GPs to promote their adoption. Establishing strong links between collecting Aboriginal and Torres Strait Islander status, clinical decision supports, and uptake of GP-mediated health measures specifically for Aboriginal and Torres Strait Islander peoples - and embedding these links in GP software - is a long overdue reform. In the absence of government initiatives in this area, GPs are best placed to advocate for software changes, using the model described here as a starting point for action.

  2. Oil spills prediction in the Bonifacio strait area, western Mediterranean

    Directory of Open Access Journals (Sweden)

    A. Cucco

    2012-02-01

    Full Text Available An innovative forecasting system of the coastal marine circulation has been implemented in the Bonifacio Strait area, between Corsica and Sardinia, using a numerical approach to facilitate the rapid planning and coordination of remedial actions to oil spill emergencies at sea by local authorities. Downscaling and nesting techniques from regional to coastal scale and a 3-D hydrodynamic numerical model, coupled with a wind wave model, are the core of the integrated Bonifacio Strait system. Such a system is capable to predict the sea state and the dispersion of hydrocarbon spills in the area, providing the forecasts on oil spills through an easy-to-use graphical user interface. Scenarios and risk maps have been created to identify the most risky areas to oil pollution in relation to vessels traffic. The backward investigation technique has been exploited to trace the most probable area from which pollution was generated. The system has been operationally verified in January 2011 when an oil spill occurred in the area. Finally output data are daily released providing forecasting services to end-users through the web.

  3. On locating local earthquakes at the Messina Strait network

    Directory of Open Access Journals (Sweden)

    G. NERI

    1980-06-01

    Full Text Available A computer program (HYPOSTRE has been elaborated to determine
    the hypocentral parameters of local earthquakes, even when they are recorded
    by a small number of stations. These are the most frequent conditions
    prevailing around the Strait of Messina.
    The program employs the first arrivals of P and S waves, a model of
    local crust consisting of four plane and parallel layers, and an algorithm
    based on that of Geiger.
    HYPOSTRE can determine simultaneously the four unknowns X, cp, h
    and H (HYPOSTRE 4 and can calculate the epicentral coordinate separately
    from focal depth (HYPOSTRE 2. In both cases the program follows
    an iterative process. In particular, HYPOSTRE 2 shows convergence towards
    a final solution, through a series of « damped » approximations.
    The application of HYPOSTRE to about twenty earthquakes, which
    have occured in the Strait of Messina and in the Gulf of Patti, demonstrates
    a good convergence and a general stability of results.
    Finally, comparison with analogous determinations — carried out by
    other programs, with different crustal models and using a greater number
    of recorded data — confirms the reliability of HYPOSTRE.

  4. Anomalous dispersion of sea ice in the Fram Strait region

    Science.gov (United States)

    Gabrielski, A.; Badin, G.; Kaleschke, L.

    2015-03-01

    The single-particle dispersion of sea ice in the Fram Strait region is investigated using ice drift buoys deployed from 2002 to 2009 within the Fram Strait Cyclones and the Arctic Climate System Study campaigns. A new method to estimate the direction of the mean flow, based on a satellite drift product, is introduced. As a result, the bias in the dispersion introduced by the mean flow is eliminated considering only the displacements of the buoys in the cross-stream direction. Results show an absolute dispersion growing quadratically in time for the first 3 days and an anomalous dispersion regime exhibiting a strongly self-similar scaling following a 5/4 power law for time scales larger than 6 days persisting over the whole time series of length 32 days. The non-Gaussian distribution of the velocity fluctuations with a skewness of -0.15 and a kurtosis of 7.33 as well as the slope of the Lagrangian frequency spectrum between -2 and -1 are in agreement with the anomalous diffusion regime. Comparison with data from the International Arctic Buoy Program yields similar results with an anomalous dispersion starting after 10 days and persisting over the whole time series of length 50 days. The results suggest the presence of deformation and shear acting on the sea ice dispersion. The high correlation between the cross-stream displacements and the cross-stream wind velocities shows the important role of the wind as a source for the anomalous dispersion.

  5. Oil spills prediction in the Bonifacio strait area, western Mediterranean

    Science.gov (United States)

    Cucco, A.; Ribotti, A.; Olita, A.; Fazioli, L.; Sorgente, B.; Sinerchia, M.; Satta, A.; Perilli, A.; Borghini, M.; Schroeder, K.; Sorgente, R.

    2012-02-01

    An innovative forecasting system of the coastal marine circulation has been implemented in the Bonifacio Strait area, between Corsica and Sardinia, using a numerical approach to facilitate the rapid planning and coordination of remedial actions to oil spill emergencies at sea by local authorities. Downscaling and nesting techniques from regional to coastal scale and a 3-D hydrodynamic numerical model, coupled with a wind wave model, are the core of the integrated Bonifacio Strait system. Such a system is capable to predict the sea state and the dispersion of hydrocarbon spills in the area, providing the forecasts on oil spills through an easy-to-use graphical user interface. Scenarios and risk maps have been created to identify the most risky areas to oil pollution in relation to vessels traffic. The backward investigation technique has been exploited to trace the most probable area from which pollution was generated. The system has been operationally verified in January 2011 when an oil spill occurred in the area. Finally output data are daily released providing forecasting services to end-users through the web.

  6. Cretaceous to Recent extension in the Bering Strait region, Alaska

    Science.gov (United States)

    Dumitru, Trevor A.; Miller, Elizabeth L.; O'Sullivan, Paul B.; Amato, Jeffrey M.; Hannula, Kimberly A.; Calvert, Andrew T.; Gans, Phillip B.

    1995-06-01

    A key issue presented by the geology of northern Alaska concerns the demise of the Brooks Range going west toward the Bering Strait region. The main Brookian tectonic and stratigraphic elements continue into the Russian Far East, but the thick crustal root and high elevations that define the modern physiographic Brooks Range die out approaching the Bering and Chukchi shelves, which form an unusually broad area of submerged continental crust. Structural, geochronologic, and apatite fission-track data indicate that at least three episodes of extension may have affected the crust beneath the Bering Strait region, in the middle to Late Cretaceous, Eocene-early Oligocene, and Pliocene(?)-Recent. This extension may explain the present thinner crust of the region, the formation of extensive continental shelves, and the dismemberment and southward translation of tectonic elements as they are traced from the Brooks Range toward Russia. Evidence for these events is recorded within a gently tilted 10- to 15-km thick crustal section exposed on the western Seward Peninsula. The earliest episode is documented at high structural levels by the postcollision exhumation history of blueschists. Structural data indicate exhumation was accomplished in part by thinning of the crust during north-south extension bracketed between 120 and 90 Ma by 40Ar/39Ar and U-Pb ages. The Kigluaik Mountains gneiss dome rose through the crust during the later stages of this extension at 91 Ma. Similar gneiss domes occur within a broad, discontinuous belt of Cretaceous magmatism linking interior Alaska with northeast Russia; mantle-derived melts within this belt likely heated the crust and facilitated extension. Apatite fission-track ages indicate cooling below ≈120-85°C occurred sometime between 100 and 70 Ma, and the area subsequently resided at shallow crustal depths (<3-4 km) until the present. This suggests that denudation of deep levels of the crust by erosion and/or tectonism was mostly

  7. Managing Human Activities in Antarctica : Should Wilderness Protection Count?

    NARCIS (Netherlands)

    Bastmeijer, C.J.

    2005-01-01

    Antarctica is often described as one of the world's last wildernesses. In harmony with this general perception, the wilderness values of Antarctica received legal status with the adoption of the Protocol on Environmental Protection to the Antarctic Treaty. Article 3(1) of the Protocol obliges each C

  8. Sensitivity analysis of the physical dynamics of the Fly River plume in Torres Strait

    Science.gov (United States)

    Li, Yanfang; Martins, Flavio; Wolanski, Eric

    2017-07-01

    The intrusion in the Torres Strait of the Fly River plume polluted by mine tailings is an international water issue. To investigate the physical mechanisms involved in the intrusion process, numerical simulations were conducted to assess the relative influence of the bathymetry and the external forcing, namely the tides, the mean sea level slope across the strait, river runoff and wind forcing. The wind data from Horn Island, the only long-term wind station in the Torres Strait, is shown to be unreliable due to orographic effects. Mean sea level data from altimetry compare well with those from tide gauges in these shallow, reef-studded waters. The wind has a dominant effect on the mean sea level at seasonal and inter-annual periods. The resulting mean sea level difference across the strait fluctuated seasonally and strongly influenced the intrusion of the Fly River plume in the Torres Strait. The 3D finite-volume MOHID model reproduced the observation that the river plume starts by being stratified in the Gulf of Papua where it originates, and it mixes vertically when it enters the Torres Strait. The MOHID and the SLIM models were applied with different resolution to the Torres Strait and responded similarly to the external forcings. The predicted and observed Fly River plume intrusion in the eastern Torres Strait agreed well with each other, including the formation of patches due to flow reversals. However, the two models predicted a widely different Fly River plume in its far field in the western Torres Strait, the differences were attributed to the different bathymetry in the Australian and British-US bathymetry data for these poorly charted waters, which demonstrated the importance of the details of the bathymetry in controlling the extent of plume intrusion.

  9. Beach morphology and coastline evolution in the southern Bohai Strait

    Science.gov (United States)

    Zhang, Wei; Wu, Jianzheng; Li, Weiran; Zhu, Longhai; Hu, Rijun; Jiang, shenghui; Sun, Yonggen; Wang, Huijuan

    2015-10-01

    The beach studied in this paper spans a length of 51 km and is one of several long sandy beaches in the southern Bohai Strait. Due to the obstruction of islands in the northeast and the influence of the underwater topography, the wave environment in the offshore area is complex; beach types and sediment transport characteristics vary along different coasts. The coastlines extracted from six aerial photographs in different years were compared to demonstrate the evolving features. Seven typical beach profiles were selected to study the lateral beach variation characteristics. Continuous wind and wave observation data from Beihuangcheng ocean station during 2009 were employed for the hindcast of the local wave environment using a regional spectral wave model. Then the results of the wave hindcast were incorporated into the LITDRIFT model to compute the sediment transport rates and directions along the coasts and analyze the longshore sand movement. The results show that the coastline evolution of sand beaches in the southern Bohai Strait has spatial and temporal variations and the coast can be divided into four typical regions. Region (I), the north coast of Qimudao, is a slightly eroded and dissipative beach with a large sediment transport rate; Region (II), the southwest coast of Gangluan Port, is a slightly deposited and dissipative beach with moderate sediment transport rate; Region (III), in the central area, is a beach that is gradually transformed from a slightly eroded dissipative beach to a moderately or slightly strong eroded bar-trough beach from west to east with a relatively moderate sediment transport rate. Region (IV), on the east coast, is a strongly eroded and reflective beach with a weak sediment transport rate. The wave conditions exhibit an increasing trend from west to east in the offshore area. The distribution of the wave-induced current inside the wave breaking region and the littoral sediment transport in the nearshore region exhibit a gradual

  10. The genus Bryoerythrophyllum (Musci, Pottiaceae in Antarctica

    Directory of Open Access Journals (Sweden)

    Sollman Philip

    2015-07-01

    Full Text Available Antarctic material of the genus Bryoerythrophyllum P. C. Chen was studied from all specimens present in KRAM. Bryoerythrophyllum recurvirostrum (Hedw. P. C. Chen var. antarcticum L. I. Savicz & Smirnova is treated as a distinct species: B. antarcticum (L. I. Savicz & Smirnova P. Sollman, stat. nov. Three species are now known in the Antarctic region: B. antarcticum, B. recurvirostrum and B. rubrum (Jur. ex Geh. P. C. Chen. Bryoerythrophyllum rubrum is reported for the first time from the Antarctic. It is a bipolar species. A key to the taxa is given. These species are described and briefly discussed, with notes on illustrations, reproduction, habitat, world range, distribution and elevation in Antarctica.

  11. Autonomous Observations in Antarctica with AMICA

    CERN Document Server

    Di Rico, Gianluca; Dolci, Mauro; Straniero, Oscar; Valentini, Angelo; Valentini, Gaetano; Di Cianno, Amico; Giuliani, Croce; Magrin, Demetrio; Bonoli, Carlotta; Bortoletto, Favio; D'Alessandro, Maurizio; Corcione, Leonardo; Riva, Alberto

    2010-01-01

    The Antarctic Multiband Infrared Camera (AMICA) is a double channel camera operating in the 2-28 micron infrared domain (KLMNQ bands) that will allow to characterize and exploit the exceptional advantages for Astronomy, expected from Dome C in Antarctica. The development of the camera control system is at its final stage. After the investigation of appropriate solutions against the critical environment, a reliable instrumentation has been developed. It is currently being integrated and tested to ensure the correct execution of automatic operations. Once it will be mounted on the International Robotic Antarctic Infrared Telescope (IRAIT), AMICA and its equipment will contribute to the accomplishment of a fully autonomous observatory.

  12. Antarctica and the strategic plan for biodiversity.

    Science.gov (United States)

    Chown, Steven L; Brooks, Cassandra M; Terauds, Aleks; Le Bohec, Céline; van Klaveren-Impagliazzo, Céline; Whittington, Jason D; Butchart, Stuart H M; Coetzee, Bernard W T; Collen, Ben; Convey, Peter; Gaston, Kevin J; Gilbert, Neil; Gill, Mike; Höft, Robert; Johnston, Sam; Kennicutt, Mahlon C; Kriesell, Hannah J; Le Maho, Yvon; Lynch, Heather J; Palomares, Maria; Puig-Marcó, Roser; Stoett, Peter; McGeoch, Melodie A

    2017-03-01

    The Strategic Plan for Biodiversity, adopted under the auspices of the Convention on Biological Diversity, provides the basis for taking effective action to curb biodiversity loss across the planet by 2020-an urgent imperative. Yet, Antarctica and the Southern Ocean, which encompass 10% of the planet's surface, are excluded from assessments of progress against the Strategic Plan. The situation is a lost opportunity for biodiversity conservation globally. We provide such an assessment. Our evidence suggests, surprisingly, that for a region so remote and apparently pristine as the Antarctic, the biodiversity outlook is similar to that for the rest of the planet. Promisingly, however, much scope for remedial action exists.

  13. Antarctica: measuring glacier velocity from satellite images.

    Science.gov (United States)

    Lucchitta, B K; Ferguson, H M

    1986-11-28

    Many Landsat images of Antarctica show distinctive flow and crevasse features in the floating part of ice streams and outlet glaciers immediately below their grounding zones. Some of the features, which move with the glacier or ice stream, remain visible over many years and thus allow time-lapse measurements of ice velocities. Measurements taken from Landsat images of features on Byrd Glacier agree well with detailed ground and aerial observations. The satellite-image technique thus offers a rapid and cost-effective method of obtaining average velocities, to a first order of accuracy, of many ice streams and outlet glaciers near their termini.

  14. Exhumation of the Shackleton Range, Antarctica

    Science.gov (United States)

    Lucka, Nicole; Lisker, Frank; Läufer, Andreas; Spiegel, Cornelia

    2013-04-01

    The Shackleton Range is situated between 80° - 81°S and 19° - 31°W, where it forms the continuation of the Transantarctic Mountains in the Weddell Sea sector of Antarctica. There, Precambrian igneous and metamorphic basement is overlain by (meta-) sedimentary rocks of an Early Paleozoic nappe stack and post-orogenic red beds. Nappe stacking resulted from the collision of East and West Gondwana due to the closure of the Mozambique Ocean in pan-African times. The uplift and exhumation history of the Shackleton Range has been analysed earlier based on a series of vertical fission track profiles (Schäfer, 1998; Lisker et al., 1999). Zircon ages range from ~160 to 210 Ma while apatite ages between ~95 and ~170 Ma comprise a break in slope of the altitude regression at ~110 Ma, and are accompanied by mean track lengths of 12.7 - 14.1 µm (standard deviation 1.0 - 1.4 µm). These data have been interpreted qualitatively in terms of two cooling/ exhumation stages during Jurassic and mid-Cretaceous times. However, the recognition of Jurassic volcaniclastic rocks associated with the ~180 Ma Ferrar event in the vicinity of the sample locations (Buggisch et al., 1994) challenges this exhumation concept. Moreover, new fission track proxy data (Dpar) and apatite (U-Th-Sm)/He ages between 88 and 171 Ma allow thermal history modelling of the combined thermochronological data. First tentative thermal history models suggest early Mesozoic cooling followed by (post-) Jurassic heating and final cooling since the Late Cretaceous. This scenario requires burial of the Shackleton Range region, and therefore the existence of a sedimentary basin at least during the Jurassic-Early Cretaceous, and subsequent basin inversion. The thickness of the now vanished sedimentary strata did unlikely exceed 2 - 3 km. Future work including additional apatite fission track analyses will help to quantifying geometry, depth and timing of this depocentre and evaluating potential links with the coeval

  15. Strait of Gibraltar, Perspective with Landsat Image Overlay

    Science.gov (United States)

    2003-01-01

    This perspective view shows the Strait of Gibraltar, which is the entrance to the Mediterranean Sea from the Atlantic Ocean. Europe (Spain) is on the left. Africa (Morocco) is on the right. The Rock of Gibraltar, administered by Great Britain, is the peninsula in the back left.The Strait of Gibraltar is the only natural gap in the topographic barriers that separate the Mediterranean Sea from the world's oceans. The Sea is about 3700 kilometers (2300 miles) long and covers about 2.5 million square kilometers (one million square miles), while the Strait is only about 13 kilometers (8 miles) wide. Sediment samples from the bottom of the Mediterranean Sea that include evaporite minerals, soils, and fossil plants show that about five million years ago the Strait was topographically blocked and the Sea had evaporated into a deep basin far lower in elevation than the oceans. Consequent changes in the world's hydrologic cycle, including effects upon ocean salinity, likely led to more ice formation in polar regions and more reflection of sunlight back to space, resulting in a cooler global climate at that time. Today, topography plays a key role in our regional climate patterns. But through Earth history, topographic change, even perhaps over areas as small as 13 kilometers across, has also affected the global climate.This image was generated from a Landsat satellite image draped over an elevation model produced by the Shuttle Radar Topography Mission (SRTM). The view is eastward with a 3-times vertical exaggeration to enhance topographic expression. Natural colors of the scene (green vegetation, blue water, brown soil, white beaches) are enhanced by image processing, inclusion of some infrared reflectance (as green) to highlight the vegetation pattern, and inclusion of shading of the elevation model to further highlight the topographic features.Landsat has been providing visible and infrared views of the Earth since 1972. SRTM elevation data matches the 30-meter (99-feet

  16. Analysis of upwelling event in Southern Makassar Strait

    Science.gov (United States)

    Utama, F. G.; Atmadipoera, A. S.; Purba, M.; Sudjono, E. H.; Zuraida, R.

    2017-01-01

    The southeast monsoon (SEM) winds which blow in southern Makassar Strait, generate the coastal upwelling phenomenon. The wind data for one year, which is equipped with CTD data from MAJAFLOX cruise results, is used to analyze the phenomenon of upwelling in this region. During the SEM 2015 occurrence, the southeasterly winds speed were in average of 6 m/s, while the highest speed appeared in August and September. Using the Ekman theory’s analysis of upwelling during this monsoon period, we could estimate the Ekman transport was about 8.50 m2/s toward offshore (to the Southwest direction); the upwelled water, occurred from deeper layer, started from the coastal area with vertical velocity was about 6.87 x 10-5 m/s – 7.84 x 10-5 m/s; and The Ekman layer depth in the upwelling region was approximately 60 m and these were good agreement with CTD observation result.

  17. Fram Strait Spring Ice Export and September Arctic Sea Ice

    Science.gov (United States)

    Smedsrud, Lars H.; Halvorsen, Mari H.; Stroeve, Julienne; Zhang, Rong; Kloster, Kjell

    2016-04-01

    The Arctic Basin exports between 600 000 - 1 million km² of it's sea ice cover southwards through Fram Strait each year, comparing to about 10% of the ice covered area inside the basin. During winter ice export results in growth of new and relatively thin ice inside the basin, while during summer or spring export contributes directly to open water further north. A new updated time series from 1935 to 2014 of Fram Strait sea ice area export shows that the long-term annual mean export is about 880,000 km², with large annual and decadal variability and no long-term trend over the past 80 years. Nevertheless, the last decade has witnessed increased annual ice export, with several years having annual ice export exceed 1 million km². Evaluating the trend onwards from 1979, when satellite based sea ice coverage became more readily available, reveals an increase in annual export of about +6% per decade. This increase is caused by higher southward ice drift speeds due to stronger southward geostrophic winds, largely explained by increasing surface pressure over Greenland. Spring and summer area export increased more (+11% per decade) than in autumn and winter. Contrary to the last decade the 1950 - 1970 period had low export during spring and summer, and mid-September sea ice extent was consistently higher than both before and after these decades. We thus find that export anomalies during spring have a clear influence on the following September sea ice extent in general, and that for the recent decade the export may be partially responsible for the accelerating decline in Arctic sea ice extent.

  18. Tidal propagation and dissipation in the Taiwan Strait

    Science.gov (United States)

    Yu, Haiqing; Yu, Huaming; Wang, Lu; Kuang, Liang; Wang, Hui; Ding, Yang; Ito, Shin-ichi; Lawen, Johannes

    2017-03-01

    Previous research on tides and tidal dynamics in the Taiwan Strait (TS) is reviewed in this paper. Tidal dynamics, which is the basic and dominant hydrodynamics in this area, attracts much interest in the last 30 years and till now its physical mechanism is still in debate. In this study, the major research methods and findings of previous works on barotropic tides in the TS are summarized. Based on Finite Volume Coastal Ocean Model (FVCOM), the main tidal constituents (M2, S2, K1, O1) are well simulated with the mean root-mean-square (RMS) errors of 4.7, 2.0, 1.3 and 0.7 cm between the observed and simulated tidal constants, respectively. It has been proved that semi-diurnal tidal movement is mainly determined by the waves from the East China Sea (ECS), while waves from the ECS and the Luzon Strait (LS) play comparable roles in diurnal tidal movement in the TS by linear superposition and the interaction of these two waves is the main cause for the progressive diurnal tidal waves in the TS. Furthermore, energy analysis revealed that the M2 tidal wave system in the TS and its adjacent area south to the shoal is an standing wave system and the anti-node appears in the central TS while the wave node locates in the shoal area, which can be contributed to the interaction of the incident waves from the ECS and the topography step south to Taiwan island, while the shoal also has an impact on the whole semi-diurnal tidal wave system in the TS. This standing wave system is consistent with the little energy dissipation in the central TS and much energy dissipation in the southern TS, where the shallow water effect also contributes to the local dissipation to some extent.

  19. Wind forcing of salinity anomalies in the Denmark Strait overflow

    Directory of Open Access Journals (Sweden)

    S. Hall

    2011-06-01

    Full Text Available The overflow of dense water from the Nordic Seas to the North Atlantic through Denmark Strait is an important part of the global thermohaline circulation. The salinity of the overflow plume has been measured by an array of current meters across the continental slope off the coast of Angmagssalik, southeast Greenland since September 1998. During 2004 the salinity of the overflow plume changed dramatically, with the entire width of the array (70 km freshening between January 2004 and July 2004, with a significant negative salinity anomaly of about 0.06 in May. The event in May represents a fresh anomaly of over 3 standard deviations from the mean since recording began in 1998. We show that the OCCAM 1/12° Ocean General Circulation Model not only reproduces the 2004 freshening event (r=0.96, p<0.01, but also correlates well with salinity observations over a previous 6 year period (r=0.54, p<0.01. Consequently the physical processes causing the 2004 anomaly and prior variability in salinity are investigated using the model output. Our results reject the hypotheses that the anomaly is caused by processes occurring between the overflow sill and the moorings, or by an increase in upstream net freshwater input. Instead, we show that the 2004 salinity anomaly is caused by an increase in volume flux of low salinity water, with a potential density greater than 27.60 kg m−3, flowing towards the Denmark Strait sill in the East Greenland Current. This is caused by an increase of southward wind stress upstream of the sill at around 75° N 20° W four and a half months earlier, and an associated spin-up of the Greenland Sea Gyre.

  20. Deglacial temperature history of West Antarctica

    Science.gov (United States)

    Cuffey, Kurt M.; Clow, Gary D.; Steig, Eric J.; Buizert, Christo; Fudge, T. J.; Koutnik, Michelle; Waddington, Edwin D.; Alley, Richard B.; Severinghaus, Jeffrey P.

    2016-12-01

    The most recent glacial to interglacial transition constitutes a remarkable natural experiment for learning how Earth’s climate responds to various forcings, including a rise in atmospheric CO2. This transition has left a direct thermal remnant in the polar ice sheets, where the exceptional purity and continual accumulation of ice permit analyses not possible in other settings. For Antarctica, the deglacial warming has previously been constrained only by the water isotopic composition in ice cores, without an absolute thermometric assessment of the isotopes’ sensitivity to temperature. To overcome this limitation, we measured temperatures in a deep borehole and analyzed them together with ice-core data to reconstruct the surface temperature history of West Antarctica. The deglacial warming was 11.3±1.8∘11.3±1.8∘C, approximately two to three times the global average, in agreement with theoretical expectations for Antarctic amplification of planetary temperature changes. Consistent with evidence from glacier retreat in Southern Hemisphere mountain ranges, the Antarctic warming was mostly completed by 15 kyBP, several millennia earlier than in the Northern Hemisphere. These results constrain the role of variable oceanic heat transport between hemispheres during deglaciation and quantitatively bound the direct influence of global climate forcings on Antarctic temperature. Although climate models perform well on average in this context, some recent syntheses of deglacial climate history have underestimated Antarctic warming and the models with lowest sensitivity can be discounted.

  1. The Landsat Image Mosaic of Antarctica

    Science.gov (United States)

    Bindschadler, R.; Vornberger, P.; Fleming, A.; Fox, A.; Mullins, J.; Binnie, D.; Paulsen, S.J.; Granneman, B.; Gorodetzky, D.

    2008-01-01

    The Landsat Image Mosaic of Antarctica (LIMA) is the first true-color, high-spatial-resolution image of the seventh continent. It is constructed from nearly 1100 individually selected Landsat-7 ETM+ scenes. Each image was orthorectified and adjusted for geometric, sensor and illumination variations to a standardized, almost seamless surface reflectance product. Mosaicing to avoid clouds produced a high quality, nearly cloud-free benchmark data set of Antarctica for the International Polar Year from images collected primarily during 1999-2003. Multiple color composites and enhancements were generated to illustrate additional characteristics of the multispectral data including: the true appearance of the surface; discrimination between snow and bare ice; reflectance variations within bright snow; recovered reflectance values in regions of sensor saturation; and subtle topographic variations associated with ice flow. LIMA is viewable and individual scenes or user defined portions of the mosaic are downloadable at http://lima.usgs.gov. Educational materials associated with LIMA are available at http://lima.nasa.gov.

  2. The vulnerability of the Strait of Georgia (Canada) to future hypoxia and ocean acidification

    Science.gov (United States)

    Ianson, Debby; Allen, Susan; Moore-Maley, Ben; Haigh, Rowan; Johannessen, Sophia; Macdonald, Robie; Krogh, Jeremy; Simpson, Eleanor; Kohfeld, Karen; Hamme, Roberta

    2016-04-01

    The Canadian Pacific coast is filled with fjords and islands. Circulation in the region is dynamic, so that large changes in acidity (pH) and oxygen may occur both in space and time. The Strait of Georgia (Canada) is a large (200 X 30 km) semi-enclosed basin, that has relatively low pH with respect to the adjacent outer coast and yet hosts a lucrative aquaculture industry. On the other hand this region is relatively well oxygenated due to gas exchange in the turbulent (tidal) flow in the narrow Straits with sills connecting it with the outer coast. We investigate the role that this intense gas exchange plays in protecting the Strait of Georgia from future hypoxia and ocean acidification. Finally, we contrast surface water properties (including dissolved inorganic carbon and total alkalinity) measured on large ships with those measured nearshore and at shore-based aquaculture sites within the Strait.

  3. Cultural safety and maternity care for Aboriginal and Torres Strait Islander Australians.

    Science.gov (United States)

    Kruske, Sue; Kildea, Sue; Barclay, Lesley

    2006-09-01

    To discuss cultural safety and critique the provision of culturally appropriate maternity services to remote Aboriginal and Torres Strait Islander women in Australia. The literature and policies around 'culture' and 'cultural safety' are discussed and applied to the provision of maternity services to Aboriginal and Torres Strait Islander women in remote areas of Australia. The current provision of maternity services to Aboriginal and Torres Strait Islander women, particularly those living in remote Australia, appears largely inadequate. The provision of culturally safe maternity care requires health system reform at all levels including: the individual practitioner response; the educational preparation of practitioners; the delivery of maternity services and the development of policy at local, state and national level. This paper considers the changes that can be made from the individual practitioner through to the design and implementation of maternity services. Cultural safety provides a useful framework to improve the delivery of maternity services to remote Aboriginal and Torres Strait Islander women and their families.

  4. Gravity cores from San Pablo Bay and Carquinez Strait, San Francisco Bay, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data release contains information on gravity cores that were collected by the U.S. Geological Survey in the area of San Pablo Bay and Carquinez Strait,...

  5. Seasonal and interannual variability of the water exchange in the Turkish Straits System estimated by modelling

    Directory of Open Access Journals (Sweden)

    V. MADERICH

    2015-07-01

    Full Text Available A chain of simple linked models is used to simulate the seasonal and interannual variability of the Turkish Straits System. This chain includes two-layer hydraulic models of the Bosphorus and Dardanelles straits simulating the exchange in terms of level and density difference along each strait, and a one-dimensional area averaged layered model of the Marmara Sea. The chain of models is complemented also by the similar layered model of the Black Sea proper and by a one-layer Azov Sea model with the Kerch Strait. This linked chain of models is used to study the seasonal and interannual variability of the system in the period 1970-2009. The salinity of the Black Sea water flowing into the Aegean Sea increases by approximately 1.7 times through entrainment from the lower layer. The flow entering into the lower layer of the Dardanelles Strait from the Aegean Sea is reduced by nearly 80% when it reaches the Black Sea. In the seasonal scale, a maximal transport in the upper layer and minimal transport in the bottom layer are during winter/spring for the Bosphorus and in spring for the Dardanelles Strait, whereas minimal transport in upper layer and maximal undercurrent are during the summer for the Bosphorus Strait and autumn for the Dardanelles Strait. The increase of freshwater flux into the Black Sea in interannual time scales (41 m3s-1 per year is accompanied by a more than twofold growth of the Dardanelles outflow to the North Aegean (102 m3s-1 per year.

  6. Seasonally Resolved Surface Water (delta)14C Variability in the Lombok Strait: A Coralline Perspective

    Energy Technology Data Exchange (ETDEWEB)

    Guilderson, T P; Fallon, S J; Moore, M D; Schrag, D P; Charles, C D

    2008-04-23

    We have explored surface water mixing in the Lombok Strait through a {approx}bimonthly resolved surface water {Delta}{sup 14}C time-series reconstructed from a coral in the Lombok Strait that spans 1937 through 1990. The prebomb surface water {Delta}{sup 14}C average is -60.5{per_thousand} and individual samples range from -72{per_thousand} to 134{per_thousand}. The annual average post-bomb maximum occurs in 1973 and is 122{per_thousand}. The timing of the post-bomb maximum is consistent with a primary subtropical source for the surface waters in the Indonesian Seas. During the post-bomb period the coral records regular seasonal cycles of 5-20{per_thousand}. Seasonal high {Delta}{sup 14}C occur during March-May (warm, low salinity), and low {Delta}{sup 14}C occur in September (cool, higher salinity). The {Delta}{sup 14}C seasonality is coherent and in phase with the seasonal {Delta}{sup 14}C cycle observed in Makassar Strait. We estimate the influence of high {Delta}{sup 14}C Makassar Strait (North Pacific) water flowing through the Lombok Strait using a two endmember mixing model and the seasonal extremes observed at the two sites. The percentage of Makassar Strait water varies between 16 and 70%, and between 1955 and 1990 it averages 40%. During La Nina events there is a higher percentage of Makassar Strait (high {Delta}{sup 14}C) water in the Lombok Strait.

  7. Physical characteristic of brown algae (Phaeophyta) from madura strait as irreversible hydrocolloid impression material

    OpenAIRE

    Prihartini Widiyanti; Siswanto Siswanto

    2012-01-01

    Background: Brown algae is a raw material for producing natrium alginates. One type of brown algae is Sargassum sp, a member of Phaeophyta division. Sargassum sp could be found in Madura strait Indonesia. Natrium alginate can be extracted from Sargassum sp. The demand of alginate in Indonesia is mainly fulfilled from abroad, meanwhile Sargassum sp is abundantly available. Purpose: The purpose of study were to explore the potency of brown alga Sargassum sp from Madura strait as hydrocolloid im...

  8. Molecular variation of antarctic grass Deschampsia antarctica Desv. from King George Island (Antarctica

    Directory of Open Access Journals (Sweden)

    Katarzyna J. Chwedorzewska

    2011-01-01

    Full Text Available Deschampsia antarctica Desv. plants collected on King George Islands (Antarctica at two localities that differ in topographic and nutrition conditions exhibited morphological variation that differentiated plants of both locations. The molecular variation characteristic to individuals of both sites was tested using AFLP approach in order to verify whether morphological variation characteristic to the plants resulted from environmental factors or possibly from differences at the DNA level. Four primer pair combinations were used to generate 339 AFLP fragments, 132 of which were polymorphic and allowed evaluation of genetic relationships among D. antarctica individuals. Chi-square test revealed that only 12 signals were discriminative for the plants from both locations. Cluster analysis conducted on these AFLP fragments demonstrated that plants from the location rich in biogenes were more polymorphic than those from poor one. Our data suggest that the phenotypic variation specific to plants of both locations seem to be the result of adaptation to the environmental conditions like soil and moisture rather than reflect genetic differences.

  9. Environmental controls of marine productivity hot spots around Antarctica

    National Research Council Canada - National Science Library

    Arrigo, Kevin R; van Dijken, Gert L; Strong, Aaron L

    2015-01-01

    ...) in 46 coastal polynyas around Antarctica. Data presented here suggest that melting ice shelves are a primary supplier of Fe to coastal polynyas, with basal melt rates explaining 59% of the between...

  10. Antarctica and the strategic plan for biodiversity

    Science.gov (United States)

    Chown, Steven L.; Brooks, Cassandra M.; Terauds, Aleks; Le Bohec, Céline; van Klaveren-Impagliazzo, Céline; Whittington, Jason D.; Butchart, Stuart H. M.; Coetzee, Bernard W. T.; Collen, Ben; Convey, Peter; Gaston, Kevin J.; Gilbert, Neil; Gill, Mike; Höft, Robert; Johnston, Sam; Kennicutt, Mahlon C.; Kriesell, Hannah J.; Le Maho, Yvon; Lynch, Heather J.; Palomares, Maria; Puig-Marcó, Roser; Stoett, Peter; McGeoch, Melodie A.

    2017-01-01

    The Strategic Plan for Biodiversity, adopted under the auspices of the Convention on Biological Diversity, provides the basis for taking effective action to curb biodiversity loss across the planet by 2020—an urgent imperative. Yet, Antarctica and the Southern Ocean, which encompass 10% of the planet’s surface, are excluded from assessments of progress against the Strategic Plan. The situation is a lost opportunity for biodiversity conservation globally. We provide such an assessment. Our evidence suggests, surprisingly, that for a region so remote and apparently pristine as the Antarctic, the biodiversity outlook is similar to that for the rest of the planet. Promisingly, however, much scope for remedial action exists. PMID:28350825

  11. Characteristics of Marine Recreational Fishing in the anakkale Strait (Turkey

    Directory of Open Access Journals (Sweden)

    V. UNAL

    2012-12-01

    Full Text Available The economic and harvest impacts of Marine Recreational Fishing (MRF in Çanakkale Strait were analysed along with fishing policy, sociology and habits of fishers. Data sources included field survey data carried out along the entire length of the Çanakkale strait and policy information gathered from published sources. MRF policy is commendable, even in the fishing tourism sector, and is better developed than that in many other European countries. In Çanakkale, 9.9% of the population is recreational fishers. Recreational fishers are typically men (90%, primarily those between the ages of 25 and 49 yrs. The occupation of the recreational fishers ranged from self-employed (28%, students (28%, retired persons (22% and public employees (15%, to currently-unemployed persons (7%. An analysis of diel behaviour showed that most recreational fishers preferred fishing during the day (56.1%, while the evening was the next most preferred time for fishing (18%, followed by the night-time (9.8%, while a substantial number of recreational fishers (16.1% reported that they fished at any time of day. The most popular type of fishing was shore-based (68%, followed by boat-based (21%, and underwater fishing (11%. The mean daily fishing times were 6.07 h d-1, 6.18 h d-1 4.75 d-1 for boat-based, underwater and shore-based fishing, respectively. Summer and autumn were the preferred seasons for shore-based and underwater fishing, while autumn and winter were preferred for boat-based fishing. The highest Catch per Unit Effort (CPUE was observed for boat-based fishing (2.77 kg h-1, followed by underwater (0.97 kg h-1 and shore-based fishing (0.81 kg h-1. The catch composition included 51 species, though the catch composition of each fishing type was mostly comprised of only 3 or 4 species. The impact of the MRF harvest was high (30% of commercial fishing, particularly for bluefish (Pomatomus saltatrix and picarel (Spicara smaris species. The economic impact of MRF was

  12. Water, heat and salt transport through the Strait of Otranto

    Science.gov (United States)

    Yari, Sadegh; Gačić, Miroslav; Kovačević, Vedrana; Cardin, Vanessa

    2010-05-01

    The water, heat and salt transports through the Strait of Otranto are estimated applying direct method to historical current and hydrographical data (from December 94 through November 95). A variational inverse method based on a variational principle and a finite element solver is used to reconstruct the current, temperature and salinity fields across the Strait section from sparse measurements. The mean annual inflow and outflow water transport rates are estimated as 0.901±0.039 Sv and -0.939±0.315 Sv, respectively, and the net transport for the period of study is equal to -0.032±0.208 Sv. Thus, on a yearly time interval, the inflow and the outflow are practically compensated. The heat and salt transports due to advection process are estimated for five monthly periods, namely December 1994, February, May, August and November 1995. Considering these five periods representative of the seasonal cycle during the year, their average values show that there is a net heat advection into the Adriatic Sea on a yearly basis. The estimated value of advected heat and the corresponding error are 2.408±0.490 TW, which is equivalent to a heat gain of 17.37±3.53 W m-2 for the whole basin. This value is compared to the heat loss of -36±152 (std) W m-2 through the air-sea interface calculated by means of bulk formulas over the Adriatic Sea. The two values are expected to be balance each other in order to close the heat budget of the basin. The possible reasons for this difference to occur are discussed. On a yearly basis, the salt transport is estimated as an input of salt equal to 0.05×106 Kg s-1. The average annual fresh water budget is estimated as -0.002 Sv, equivalent to the mass of fresh water of 2.00×106Kg s-1 or to the level of 0.45 m yr-1 for the entire Adriatic Sea. The import of salt that is less than the gain of fresh water is in agreement with the fact that the Adriatic Sea is a dilution basin.

  13. Characteristics of Marine Recreational Fishing in the anakkale Strait (Turkey

    Directory of Open Access Journals (Sweden)

    V. UNAL

    2010-11-01

    Full Text Available The economic and harvest impacts of Marine Recreational Fishing (MRF in Çanakkale Strait were analysed along with fishing policy, sociology and habits of fishers. Data sources included field survey data carried out along the entire length of the Çanakkale strait and policy information gathered from published sources. MRF policy is commendable, even in the fishing tourism sector, and is better developed than that in many other European countries. In Çanakkale, 9.9% of the population is recreational fishers. Recreational fishers are typically men (90%, primarily those between the ages of 25 and 49 yrs. The occupation of the recreational fishers ranged from self-employed (28%, students (28%, retired persons (22% and public employees (15%, to currently-unemployed persons (7%. An analysis of diel behaviour showed that most recreational fishers preferred fishing during the day (56.1%, while the evening was the next most preferred time for fishing (18%, followed by the night-time (9.8%, while a substantial number of recreational fishers (16.1% reported that they fished at any time of day. The most popular type of fishing was shore-based (68%, followed by boat-based (21%, and underwater fishing (11%. The mean daily fishing times were 6.07 h d-1, 6.18 h d-1 4.75 d-1 for boat-based, underwater and shore-based fishing, respectively. Summer and autumn were the preferred seasons for shore-based and underwater fishing, while autumn and winter were preferred for boat-based fishing. The highest Catch per Unit Effort (CPUE was observed for boat-based fishing (2.77 kg h-1, followed by underwater (0.97 kg h-1 and shore-based fishing (0.81 kg h-1. The catch composition included 51 species, though the catch composition of each fishing type was mostly comprised of only 3 or 4 species. The impact of the MRF harvest was high (30% of commercial fishing, particularly for bluefish (Pomatomus saltatrix and picarel (Spicara smaris species. The economic impact of MRF was

  14. Caloplaca coeruleofrigida sp. nova, a species from continental Antarctica

    DEFF Research Database (Denmark)

    Søchting, Ulrik; Seppelt, R.

    2003-01-01

    Caloplaca coeruleofrigida Søchting & Seppelt is described from Southern Victoria Land, continental Antarctica. It is characterized by vertically elongated papillae and a pale orange pigmentation on shaded parts, and black thallus and apothecia on exposed parts of the thallus......Caloplaca coeruleofrigida Søchting & Seppelt is described from Southern Victoria Land, continental Antarctica. It is characterized by vertically elongated papillae and a pale orange pigmentation on shaded parts, and black thallus and apothecia on exposed parts of the thallus...

  15. Occurrence and Diversity of Marine Yeasts in Antarctica Environments

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xue; HUA Mingxia; SONG Chunli; CHI Zhenming

    2012-01-01

    A total of 28 yeast strains were obtained from the sea sediment of Antarctica.According to the results of routine identification and molecular characterization,the strains belonged to species of Yarrowia lipolytica,Debaryomyces hansenii,Rhodotorula slooffiae,Rhodotorula mucilaginosa,Sporidiobolus salmonicolor,Aureobasidium pullulans,Mrakia frigida and Guehomyces pullulans,respectively.The Antarctica yeasts have wide potential applications in biotechnology,for some of them can produce β-galactosidase and killer toxins.

  16. Occurrence and diversity of marine yeasts in Antarctica environments

    Science.gov (United States)

    Zhang, Xue; Hua, Mingxia; Song, Chunli; Chi, Zhenming

    2012-03-01

    A total of 28 yeast strains were obtained from the sea sediment of Antarctica. According to the results of routine identification and molecular characterization, the strains belonged to species of Yarrowia lipolytica, Debaryomyces hansenii, Rhodotorula slooffiae, Rhodotorula mucilaginosa, Sporidiobolus salmonicolor, Aureobasidium pullulans, Mrakia frigida and Guehomyces pullulans, respectively. The Antarctica yeasts have wide potential applications in biotechnology, for some of them can produce β-galactosidase and killer toxins.

  17. PERSPECTIVE How committed are we to monitoring human impacts in Antarctica?

    Science.gov (United States)

    Hughes, Kevin A.

    2010-12-01

    . References ATCM 2006 Final Report of the 29th Antarctic Treaty Consultative Meeting paragraph 73, available online at www.ats.aq/documents/ATCM29/fr/ATCM29_fr001_e.pdf Braun C et al 2010 Environmental situation and management proposals for the Fildes region (Antarctic) Int. Polar Year Conf., 8-12 June 2010 Abstract no EA8.4-6.8, available online at http://ipy-osc.no/event/8917 Chown S L and Convey P 2007 Spatial and temporal variability across life's hierarchies in the terrestrial Antarctic Phil. Trans. R. Soc. B 362 2307-31 Council of Managers of National Antarctic Programs (COMNAP) 2010 Antarctic Facilities available online at www.comnap.aq/facilities Headland R 2009 A Chronology of Antarctic Exploration (London: Quaritch) p 722 Hughes K A and Convey P 2010 The protection of Antarctic terrestrial ecosystems from inter- and intra-continental transfer of non-indigenous species by human activities: a review of current systems and practices Glob. Environ. Change 20 96-112 Kennicutt M C II, Klein A, Montagna P, Sweet S, Wade T, Palmer T, Sericano J and Denoux G 2010 Temporal and spatial patterns of anthropogenic disturbance at McMurdo Station, Antarctica Environ. Res. Lett. 5 034010 Tin T et al 2009 Impacts of local human activities on the Antarctic environment Antarct. Sci. 21 3-33 United Kingdom et al 2006 Report of joint inspections under Article VII of the Antarctic Treaty and Article 14 of the Environmental Protocol ATCM XXVIII 2006 Working paper 32, available online at www.ats.aq/documents/ATCM28/att/ATCM28_att270_e.pdf

  18. Eddies spatial variability at Makassar Strait – Flores Sea

    Science.gov (United States)

    Nuzula, F.; Syamsudin, M. L.; Yuliadi, L. P. S.; Purba, N. P.; Martono

    2017-01-01

    This study was aimed to get the distribution of eddies spatially and temporally from Makassar Waters (MW) to Flores Sea (FS), as well as its relations with the upwelling, the downwelling, and chlorophyll-a concentration. The study area extends from 115º–125º E to 2.5º–8º S. The datasets were consisted of monthly geostrophic currents, sea surface heights, sea surface temperatures, and chlorophyll-a from 2008 – 2012. The results showed that eddies which found at Makassar Strait (MS) has the highest diameter and speed of 255.3 km and 21.4 cm/s respectively, while at the southern MW has 266.4 km and 15.6 cm/s, and at FS has 182.04 km and 11.4 cm/s. From a total of 51 eddies found, the majority of eddies type was anticyclonic. At MS and FS, eddies formed along the year, whereas at southern MW were found missing in West Season. Moreover, the chlorophyll-a concentration was consistently higher at the eddies area. Even though, the correlation among eddies and the upwelling downwelling phenomena was not significantly as shown by sea surface temperatures value.

  19. Mixing and transformation in the Denmark Strait Overflow

    Science.gov (United States)

    Koszalka, Inga; Haine, Thomas; Magaldi, Marcello

    2014-05-01

    The Denmark Strait Overflow (DSO) is one of the major export routes for the dense waters from the Nordic Seas to the North Atlantic. However, the observations of the DSO are limited to a few locations and poorly resolve mixing processes that transform the dense waters and hence influence propagation of hydrographic signals from the Arctic to the Atlantic. We use a high resolution circulation model to diagnose mixing processes involving the DSO in the Irminger Basin. We focus on mesoscale (10-100km) processes, the most prominent being dense cyclonic boluses making up the overflow plume. The subgrid turbulent processes are represented by the K-profile parameterization. We map the horizontal and vertical eddy diffusivities derived from Lagrangian particles, the model vertical mixing coefficient and eddy fluxes. Our results are consistent with observations suggesting enhanced vertical mixing during the initial (~ 200km) descent of the dense plume and increasing importance of horizontal mixing downstream. The model also shows enhanced mixing along the dense water pathways in the Kangerdlugssuaq Trough on the East Greenland Shelf involving fresh Polar Waters. However, the most intense mixing is induced by mesoscale boluses of dense water cascading down the sill and the associated internal wave field. Frequent occurrence of a neutrally stratified mixed layer in the dense plume poses a challenge for the turbulent scheme of the model. We advocate for an observational campaign that would corroborate these results and help develop novel parametrizations of the vertical mixing processes in the DSO.

  20. Legally invisible: stewardship for Aboriginal and Torres Strait Islander health.

    Science.gov (United States)

    Howse, Genevieve; Dwyer, Judith

    2016-04-01

    The need to improve access to good health care for Aboriginal and Torres Strait Islander people has been the subject of policy debate for decades, but progress is hampered by complex policy and administrative arrangements and lack of clarity about the responsibilities of governments. This study aimed to identify the current legal basis of those responsibilities and define options available to Australian governments to enact enduring responsibility for Aboriginal health care. This study used a framework for public health law research and conducted a mapping study to examine the current legal underpinnings for stewardship and governance for Aboriginal health and health care. More than 200 pieces of health legislation were analysed in the context of the common and statutory law and health policy goals. Very little specific recognition of the needs of Aboriginal people was found, and nothing that creates responsibility for stewardship and governance. The continuing absence of a legislative framework to address and protect Aboriginal health can be traced back to the founding doctrine of terra nullius (unoccupied land). We considered the results applying both a human rights perspective and the perspective of therapeutic jurisprudence. We suggest that national law for health stewardship would provide a strong foundation for progress, and should itself be based on recognition of Australia's First Peoples in the Australian Constitution, as is currently proposed. © 2015 The Authors.

  1. Tide at the eastern section of the Strait of Gibraltar

    Science.gov (United States)

    Lafuente, Jesús Garcia; Vargas, Juan Miguel; Plaza, Francisco; Sarhan, Tarek; Candela, Julio; Bascheck, Burkard

    2000-06-01

    From October 1995 to April 1996, three mooring lines were deployed at the eastern entrance of the Strait of Gibraltar. The spatial coverage of the mooring array allows for a good description of the tides. They exhibit a dominant semidiurnal nature and a noticeable baroclinic structure that matches the one of the mean exchange. Tidal currents in the upper layer are irregular and usually too weak to reverse the mean upper layer flow that keeps on flowing east. Lower layer flow reverses with semidiurnal periodicity because of the smallness of the mean flow and the appreciable amplitude of the regular semidiurnal oscillation of tidal currents in this layer. Tidal transports can be satisfactorily compared with previous estimates of Bryden et al. [1994] if we allow for strong internal divergences associated with the internal tide. No significant eddy flux of water transport (tidal rectification) is observed at the eastern section, contrary to the almost 50% of the total layer transport found by Bryden et al. [1994] in Camarinal Sill section. Time-dependent hydraulic theory provides a good scenario for interpreting these two independent sets of observations despite the fact that the composite Froude number does not reach the critical values predicted in the hydraulic models most of the time.

  2. Analysis of turbulent mixing in Dewakang Sill, Southern Makassar Strait

    Science.gov (United States)

    Risko; Atmadipoera, A. S.; Jaya, I.; Sudjono, E. H.

    2017-01-01

    Dewakang Sill is located in southern Makassar Strait, conveying major path of Indonesian Throughflow (ITF), as a confluence region of different water masses, such as salty Pacific water and fresh Java Sea water. Its depth is about 680 m which blocks the ITF flow below this depth into Flores Sea. This research aimed to estimate turbulent mixing in the Dewakang Sill by applying Thorpe analysis using 24 hours “yoyo” CTD data sets, acquired from MAJAFLOX Cruise in August 2015. The results showed that stratification of water masses is dominated by Pacific water origin. Those are North Pacific Subtropical thermocline and Intermediate water masses. Mean dissipation of turbulent kinetic energy (ɛ) and turbulent vertical diffusivity (Kρ ) value in the Dewakang Sill are of O(1.08 × 10‑6)Wkg‑1, and O(2.84 × 10‑4) m2s‑1 respectively. High correlation between epsilon and internal waves oscillation suggested that internal tidal waves activities are the major forcing for turbulent mixing in the study area.

  3. Abundance of walruses in Eastern Baffin Bay and Davis Strait

    Directory of Open Access Journals (Sweden)

    Mads Peter Heide-Jørgensen

    2014-12-01

    Full Text Available Walruses (Odobenus rosmarus are exploited for subsistence purposes in West Greenland. However, current information about the abundance of walruses subject to harvest in eastern Baffin Bay subject to harvest has been unavailable despite being critical for maintaining sustainable catch levels. Three visual aerial surveys were conducted in 2006 (21 March to 19 April 2006, 2008 (3 to 12 April and 2012 (24 March to 14 April to estimate the number of walruses on the wintering grounds in eastern Baffin Bay and Davis Strait. Data on the fraction of walruses that were submerged below a 2m detection threshold during the surveys were obtained from 24 walruses instrumented with satellite-linked-time-depth-recorders in northern Baffin Bay in May-June 2010-2012. An availability correction factor was estimated at 36.5% (cv=0.08 after filtering of data for an observed drift of the pressure transducer of more than 2.5 m. The surveys resulted in walrus abundance estimates that were corrected for walruses submerged below a detection threshold and for walruses that were missed by the observers. The estimates of abundance were 1,105 (cv=0.31, 95% CI 610-2,002 in 2006, 1,137 (0.48, 468-2,758 in 2008 and 1,408 (0.22, 922-2,150 in 2012.

  4. 231Pa/230Th records of Arctic/Atlantic interchange in Fram Strait

    Science.gov (United States)

    Hoffmann, S. S.; McDermott, K. J.; McManus, J. F.; Mukasa, S. B.

    2014-12-01

    Fram Strait, the Arctic Ocean's only deep passage for exchange with lower latitude oceans, today serves as a conduit for waters flowing north into the Arctic Ocean and south into the Atlantic. Reconstruction of circulation patterns and strength at depth in the strait can help to clarify the history of Arctic/Atlantic deep water exchange and Arctic contributions to global meridional overturning circulation. We will present new sedimentary measurements of radioisotopes 231Pa and 230Th to provide information on this exchange in the past and its relationship to sedimentation and climatic events. Coretop and downcore 231Pa/230Th ratios from Arctic sediments indicate that 231Pa has been exported from the central Arctic basin throughout the Holocene and deglaciation. Fram Strait represents a possible sink for this "missing" 231Pa. Preliminary results from ODP Holes 908A and 909A, at 1274 m and 2519 m water depths respectively in the central strait, suggest that ratios in this region during the Holocene have varied between ~0.106 (above the 231Pa/230Th production ratio of 0.093 in seawater, indicating net import of 231Pa)and ~0.055 (well below the production ratio, indicating net export of 231Pa). Further measurements in cores from the Greenland and Svalbard continental slopes will give a fuller regional picture of 231Pa deposition and transport across the strait.

  5. Risk Assessment in the Istanbul Strait Using Black Sea MOU Port State Control Inspections

    Directory of Open Access Journals (Sweden)

    Esma Gül Emecen Kara

    2016-04-01

    Full Text Available The Istanbul Strait has intense maritime traffic while, at the same time, it poses significant navigational challenges. Due to these properties, there is always a high risk arising from maritime shipping in this region. Especially, substandard ships threaten life, as well as the marine environment. In this aspect, Black Sea Memorandum of Understanding (MOU Port State Control Inspections are important for maritime safety in the Istanbul Strait, because they directly reflect the performance of ships passing through the Istanbul Strait. Stringent and effective inspections assist in the enhancement of navigation safety and help to develop sustainable environment management. In this context, this study aims to assess maritime safety for the Strait region concerning passing flag states. Firstly, to assess the performance of flag states in general, the Black Sea MOU Black-Grey-White lists were generated for the period 2004–2014 and the change in the performance of these flags was examined. Secondly, the risk level of each flag state passing from the Strait region was determined using the method of weighted points based on the Black-Grey-White List, deficiency index level, casualty index level, and passing index level.

  6. Geophysical study of a crustal section across the Straits of Messina

    Directory of Open Access Journals (Sweden)

    D. SCHIAVONE

    1979-06-01

    Full Text Available This paper presents the results of geophysical researches which can
    contribute to a better definition of a structural model for the Straits of
    Messina. It is part of the seismological researches, particularly of seismic
    microzonation, which are being carried out in the area of the Straits.
    The crustal model proposed for a cross section of the Straits has
    been based, for its upper part, on data of dipole electrical soundings
    and, for its deeper structures, on seismological observations and on their
    comparison with data of active seismic.
    the Graben structure of the Straits recently proposed, with the Calabrian
    The obtained section emphasize, with some detail in the upper part, block structurally in a higher position than the Sicilian one. Such structural
    character has been put in evidence by refraction seismic sections
    to a depth of about 18 Km.
    The correlation between the structures of the area surrounding the
    Straits and the hypocentral distribution for the heaviest earthquakes with
    focus in the area is pointed out.

  7. Is the Gibraltar strait a barrier to gene flow for the bat Myotis myotis (Chiroptera: Vespertilionidae)?

    Science.gov (United States)

    Castella, V; Ruedi, M; Excoffier, L; Ibáñez, C; Arlettaz, R; Hausser, J

    2000-11-01

    Because of their role in limiting gene flow, geographical barriers like mountains or seas often coincide with intraspecific genetic discontinuities. Although the Strait of Gibraltar represents such a potential barrier for both plants and animals, few studies have been conducted on its impact on gene flow. Here we test this effect on a bat species (Myotis myotis) which is apparently distributed on both sides of the strait. Six colonies of 20 Myotis myotis each were sampled in southern Spain and northern Morocco along a linear transect of 1350 km. Results based on six nuclear microsatellite loci reveal no significant population structure within regions, but a complete isolation between bats sampled on each side of the strait. Variability at 600 bp of a mitochondrial gene (cytochrome b) confirms the existence of two genetically distinct and perfectly segregating clades, which diverged several million years ago. Despite the narrowness of the Gibraltar Strait (14 km), these molecular data suggest that neither males, nor females from either region have ever reproduced on the opposite side of the strait. Comparisons of molecular divergence with bats from a closely related species (M. blythii) suggest that the North African clade is possibly a distinct taxon warranting full species rank. We provisionally refer to it as Myotis cf punicus Felten 1977, but a definitive systematic understanding of the whole Mouse-eared bat species complex awaits further genetic sampling, especially in the Eastern Mediterranean areas.

  8. Moho Depth Derived from Gravity Data in the Taiwan Strait Area

    Directory of Open Access Journals (Sweden)

    Hsien-Hsiang Hsieh

    2010-01-01

    Full Text Available We have constructed are gional Bouguer gravity anomaly map using marine and land data from Tai wan and the Chinese province of Fuchien, as well as SEASAT altimetry-de rived gravity data for the Tai wan Strait and its surrounding area. The map shows isogals trending generally in a NE-SW direction, conforming with the over all shallower geo logical strike of the strait. Removing gravity effects generated by the water layer and seafloor to pography, the regional Bouguer gravity anomaly is obtained, reflecting the subsurface structure. Moho depth is then computed by the Parker-Oldenburg iterative method from the regional Bouguer gravity data set. Over the strait area, the geometry of the Moho relief is smooth with an average depth of about 30 km, except for the Penghu up lift. Moho depth is shallower in the Taiwan Strait and thickens to ward both sides of the strait. The relatively shallower Moho depth, reaching up to 28 km, is convex up ward underneath the Penghu uplift.

  9. Moho Depth Derived from Gravity Data in the Taiwan Strait Area

    Directory of Open Access Journals (Sweden)

    Hsien-Hsiang Hsieh

    2010-01-01

    Full Text Available We have constructed are gional Bouguer gravity anomaly map using marine and land data from Tai wan and the Chinese province of Fuchien, as well as SEASAT altimetry-de rived gravity data for the Tai wan Strait and its surrounding area. The map shows isogals trending generally in a NE-SW direction, conforming with the over all shallower geo logical strike of the strait. Removing gravity effects generated by the water layer and seafloor to pography, the regional Bouguer gravity anomaly is obtained, reflecting the subsurface structure. Moho depth is then computed by the Parker-Oldenburg iterative method from the regional Bouguer gravity data set. Over the strait area, the geometry of the Moho relief is smooth with an average depth of about 30 km, except for the Penghu up lift. Moho depth is shallower in the Taiwan Strait and thickens to ward both sides of the strait. The relatively shallower Moho depth, reaching up to 28 km, is convex up ward underneath the Penghu uplift.

  10. Species composition and distribution of marine nematode community in the North Taiwan Strait

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Marine free-living nematodes were investigated at 13 sampling stations divided into three transects in the northern Taiwan Strait in February 1998. One hundred species of marine nematodes belonging to 91 Genera 28 Families 3 Orders were identified and were first recorded in the northern Taiwan Strait. The dominant species were Vasostoma sp., Sabatieria sp. 1, Linhystera sp. 1, Spilophorella sp., Daptonema sp., Halalaimus sp. and Dorylaimopsis variabilis. Their mean densities were all over 4 950 ind./m2. According to mean density at transects, marine nematode density decreased from coastal Weitou to off Minjiang Estuary, which was similar to polychaete distribution in the northern Taiwan Strait. The selective deposit feeder (1A) was the dominant food type of marine nematodes in the northern Taiwan Strait, but non-selective deposit feeders (1B) and epigrowth feeders (2A) occupied high proportion, indicating diverse feeding types of marine nematodes in the northern Taiwan Strait.Some environmental factors such as currents are discussed.

  11. Transport estimates in the Strait of Gibraltar with a tidal inverse model

    Science.gov (United States)

    Baschek, Burkard; Send, Uwe; Lafuente, Jesus Garcia; Candela, Julio

    2001-12-01

    To estimate the volume transport through the Strait of Gibraltar and to study the spatial structure of the time-variable flow, a varying number of current meter moorings were maintained at the eastern entrance of the strait between October 1994 and April 1998, and was complemented with intensive shipboard measurements during the European Union project Canary Island Azores Gibraltar Experiment (CANIGO). A tidal inverse model is used to merge these data sets in order to investigate the flow at the eastern entrance of the strait. The two-dimensional structure of the tidal flow was described by simple analytical functions. Harmonics with the seven most important tidal frequencies were used as temporal functions. With this model, the tidal currents can be predicted for any time and location at the eastern entrance of the strait, and more than 92% of the variance of the lower layer flow is explained. It was used to remove the tidal currents from the individual measurements and to calculate the mean flow through the strait from the residuals. Combined with a similar inverse model for determining the depth of the interface between Mediterranean and Atlantic water, the volume transport was estimated to be 0.81±0.07 Sv for the upper layer and -0.76±0.07 Sv for the lower layer. The correlation of the tidal currents and the fluctuations of the interface accounts for ˜7% of the transport at the eastern entrance.

  12. Effective communication tools to engage Torres Strait Islanders in scientific research

    Science.gov (United States)

    Jones, A.; Barnett, B.; Williams, A. J.; Grayson, J.; Busilacchi, S.; Duckworth, A.; Evans-Illidge, E.; Begg, G. A.; Murchie, C. D.

    2008-09-01

    Often, research activities in Torres Strait have not delivered full benefit to Torres Strait Islanders due to a lack of consultation, ineffectual communication of research information and lack of empathy for the needs of Islander communities. As for other stakeholder groups, integration of Islanders into the research process through practical involvement in research may overcome these problems. Three case studies from research projects conducted in Torres Strait are discussed to highlight a variety of communication and engagement activities carried out by non-Indigenous researchers. How these communication and extension activities facilitate collaboration between Torres Strait Islander and non-Indigenous researchers provides insight in the importance of these activities to the relative success of research projects. The benefits for Islanders in collaborating with researchers may be: improved understanding of the research and how it contributes to natural resource management; a sense of control in future management decisions; a greater likelihood of successful self-regulatory management systems; enhanced skills; and increased employment opportunities. The potential benefits for researchers are enhanced support for research projects resulting in increased access to data and logistic support that may ultimately impact the successful completion of projects. Such an approach will require researchers to take time to develop relationships with Torres Strait Islanders, effectively involve Islanders in research on an equitable basis and be flexible. This will ultimately require funding organisations to recognise the importance of such activities in research proposals and provide support through sufficient funding to enable these activities to be carried out.

  13. Australia's Efforts to Improve Food Security for Aboriginal and Torres Strait Islander Peoples.

    Science.gov (United States)

    Davy, Deanna

    2016-12-01

    Australia is a wealthy country; however, available evidence suggests that food security among Aboriginal and Torres Strait Islander peoples has not yet been achieved. Aboriginal and Torres Strait Islander peoples living in remote, regional, and urban parts of Australia experience food insecurity for a number of reasons that usually include low income and a lack of access to affordable and healthy food. The much higher rate of illness and disease that this population experiences compared to non-indigenous Australians is directly related to food insecurity. This paper examines the food insecurity among Aboriginal and Torres Strait Islander peoples and recent Australian government efforts to combat this problem. The paper first considers what constitutes a human rights-based approach to achieving food security. Second, it describes the food insecurity that currently exists among Aboriginal and Torres Strait Islander peoples across the three pillars of food access, food availability, and food use. Third, the paper critically examines recent and current Australian government policy aimed at improving food security. The paper concludes with some reflections regarding how the Australian government can improve its efforts to achieve food security for Aboriginal and Torres Strait Islander peoples.

  14. Study on respiratory electron transport system (ETS) of phytoplankton in Taiwan Strait and Xiamen Harbour

    Institute of Scientific and Technical Information of China (English)

    HUANG Bangqin; HONG Huasheng; XU Xiangzhong; LIU Yuan

    2005-01-01

    Phytoplankton respiratory electron transport system (P-ETS) activities were studied in two cruises in Taiwan Strait (Aug. 1997 and Feb. -Mar. 1998) and two cruises in Xiamen Harbour (Oct., 1997 and Apr.,1998). Results showed that P-ETS activity in the surface water of southern Taiwan Strait in summer was homogeneous [mean value of 0.106 μlO2/(L.h)], inhomogeneous in northern Taiwan Strait in winter. Variation of P-ETS activity in middle part of the Strait was not obvious between summer and winter. Mean P-ETS activity of Xiamen Harbour in autumn was 0.255 μlO2/(L.h) with a little higher value in Jiulong River estuary areas. In spring, P-ETS activity was more homogeneously distributed and the mean value was 1.076 μlO2/(L.h). P-ETS activity in spring was obviously higher than in autumn in Xiamen Harbour. Vertical distribution of P-ETS in Taiwan Strait was homogeneous at some stations in winter and in summer. An obvious daily variation of P-ETS activity was recorded at Stn 9837, high at midnight and low in the early morning. Significant correlation between P-ETS activity and Chl-a was observed. Results also showed that the ratio of estimated respiratory rate to photosynthetic rate varied seasonally, high in winter (0.41) and low in summer (0.12).

  15. IMPACT OF CLIMATE ANOMALY ON CATCH COMPOSITION OF NERITIC TUNA IN SUNDA STRAIT

    Directory of Open Access Journals (Sweden)

    Khairul Amri

    2013-12-01

    Full Text Available Tongkol komo/kawakawa (Euthynnus affinis and tenggiri (Scomberomerus guttatus are commonly caught by mini purseiners operated in Sunda Straits and landed in Labuan, West Java. This species inhabits coastal water and has preference staying in relatively warm water. Oceanography parameters commonly influencing the distribution of Euthynnus affinis are temperature, current, and salinity. The oceanography of Sunda Strait is influenced by water masses coming from the north that mainly originated from the Java Sea and water masses from the south mainly originated from Indian Ocean. The internal oceanography of Sunda Strait is also influenced by upwelling and monsoon as regional climate anomaly (ENSO and Indian Ocean Dipole Mode. This paper describes the influence of Dipole Mode (positive and negative event and ENSO (El- Nino/La-Nina to the catch dynamics of neritic tuna particularly in Sunda Straits waters. The results shown that regional climate anomaly influenced neritic tuna catch and its composition. The catches Euthynnus affinis in phase negative dipole mode or La-Nina were higher and dominated the catch composition of pelagic fishes of Sunda Strait. Similar situation also is showen by Scomberomorus commerson.

  16. Comparative account of benthic community at two different locations in the continental Antarctica

    Digital Repository Service at National Institute of Oceanography (India)

    Ingole, B.S.; Dhargalkar, V.K.

    Data on faunal communities, abundance and biomass were collected from seven stations in the Queen Maud Land shelf, Lazarev Sea, East Antarctica and three stations in Atca Ice Port, Weddell Sea, West Antarctica. The sampling depth ranged from 70...

  17. 33 CFR 334.1180 - Strait of Juan de Fuca, Wash.; air-to-surface weapon range, restricted area.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Strait of Juan de Fuca, Wash.; air-to-surface weapon range, restricted area. 334.1180 Section 334.1180 Navigation and Navigable... REGULATIONS § 334.1180 Strait of Juan de Fuca, Wash.; air-to-surface weapon range, restricted area. (a) The...

  18. Study on the Tidal Wave System and Formation Mechanism of M2 Tide in the Taiwan Strait

    Institute of Scientific and Technical Information of China (English)

    ZHANG Wei-sheng; SONG Zhi-yao; ZHANG Jin-shan; ZHANG Hong-gui; KONG Jun; WANG Yan-hong

    2008-01-01

    To study the Taiwan Strait (TS), an unusual sea area, the numerical model in marginal seas of China is used to simulate and analyze the tidal wave motion in the strait. The numerical modeling experiments reproduce the amphidromic system of the M2 tide in the south end of the Taiwan strait, and consequently confirm the existence of the degenerate amphidromic system. On this basis, further discussion is conducted on the M2 system and its formation mechanism. It can be concluded that the tidal waves of the TS is consisted of the progressing wave from the north entrance and the degenerate amphidromic system from the south entrance, in which the progressing wave from the north entrance dominates the tidal wave motion in the strait. Except for the convergent effect caused by the landform and boundary, the degenerate amphidromic system produced in the south of the strait is another important factor for the following phenomena: the large tidal range in the middle of the strait, the concentrative zone of co-amplitude and co-phase line in the south of the strait. The degenerate amphidromic system is mainly produced by the incident Pacific Ocean tidal wave from the Luzon strait and the action by the shoreline and landform. The position of the amphidromic point is compelled to move toward southwest until degenerating by the powerful progressing wave from the north entrance.

  19. Multi-model ensemble estimation of volume transport through the straits of the East/Japan Sea

    Science.gov (United States)

    Han, Sooyeon; Hirose, Naoki; Usui, Norihisa; Miyazawa, Yasumasa

    2016-01-01

    The volume transports measured at the Korea/Tsushima, Tsugaru, and Soya/La Perouse Straits remain quantitatively inconsistent. However, data assimilation models at least provide a self-consistent budget despite subtle differences among the models. This study examined the seasonal variation of the volume transport using the multiple linear regression and ridge regression of multi-model ensemble (MME) methods to estimate more accurately transport at these straits by using four different data assimilation models. The MME outperformed all of the single models by reducing uncertainties, especially the multicollinearity problem with the ridge regression. However, the regression constants turned out to be inconsistent with each other if the MME was applied separately for each strait. The MME for a connected system was thus performed to find common constants for these straits. The estimation of this MME was found to be similar to the MME result of sea level difference (SLD). The estimated mean transport (2.43 Sv) was smaller than the measurement data at the Korea/Tsushima Strait, but the calibrated transport of the Tsugaru Strait (1.63 Sv) was larger than the observed data. The MME results of transport and SLD also suggested that the standard deviation (STD) of the Korea/Tsushima Strait is larger than the STD of the observation, whereas the estimated results were almost identical to that observed for the Tsugaru and Soya/La Perouse Straits. The similarity between MME results enhances the reliability of the present MME estimation.

  20. Sea level trend and variability in the Singapore Strait

    Directory of Open Access Journals (Sweden)

    P. Tkalich

    2013-03-01

    Full Text Available Sea level in the Singapore Strait (SS exhibits response to various scale phenomena, from local to global. Longest tide gauge records in SS are analysed to derive local sea level trend and annual, inter-annual and multi-decadal sea level variability, which then are attributed to regional and global phenomena. Annual data gaps are reconstructed using functions correlating sea level variability with ENSO. At annual scale, sea level anomalies in SS are (quasi-periodic monsoon-driven, of the order of ±20 cm, the highest during northeast monsoon and the lowest during southwest monsoon. Interannual regional sea level drops are associated with El Niño events, while the rises are correlated with La Niña episodes; both variations are in the range of ±5 cm. At multi-decadal scale, annual measured sea levels in SS are varying with global mean sea level, rising at the rate 1.2–1.7 mm yr−1 for 1975–2009, 1.8–2.3 mm yr−1 for 1984–2009 and 1.9–4.6 mm yr−1 for 1993–2009. When SS rates are compared with the global trends (2.0, 2.4 and 2.8 mm yr−1, respectively derived from tide gauge measurements for the same periods, they are smaller in the earlier era and considerably larger in the recent one. Taking into account the first estimate of land subsidence rate, 1–1.5 mm yr−1 in Singapore, the recent trend of absolute sea level rise in SS follows regional tendency.

  1. Application of INCSEA principles to the Taiwan Strait.

    Energy Technology Data Exchange (ETDEWEB)

    Wen-Chung, Chai (Taiwan Navy, Taiwan)

    2003-06-01

    The waters surrounding Taiwan are important international waterways. In addition to merchant ships of every nation, the warships of the United States, Japan, Russia, and China may appear in these waters. No hostility is expected between Taiwan and the United States, Japan, or Russia; however, Taiwan and China have a tense relationship, and both sides face a potential for naval incidents. As Taiwan and China expand their naval capability, the International Maritime Organization Convention for the lnternational Regulations for Preventing Collisions at Sea may not be sufficient to prevent naval incidents, any of which might develop into conflict or war. Therefore, China and Taiwan need to develop maritime confidence building measures (CBMs) that could reduce the chance of naval incidents and strengthen mutual trust and confidence. Among the variety of maritime CBM concepts for military purposes, the most successful and effective measure has been the 1972 U.S.-Soviet Union Agreement on the Prevention of Incidents On and Over the High Seas (INCSEA). The success of the agreement demonstrates that CBMs represent a workable alternative to traditional arms controls. The purpose of this paper is to suggest a concrete approach to the constraint of naval activities between China and Taiwan to reduce accidents and misunderstandings. This paper outlines the categories and characteristics of incidents at sea. Next, the author identifies the successful factors of the U.S.-Soviet INCSEA and applies the INCSEA concept to the Taiwan Strait. Finally, the author develops a framework of options and a step-by-step approach for establishing an INCSEA between Taiwan and China.

  2. The freshwater composition of the Fram Strait outflow derived from a decade of tracer measurements

    DEFF Research Database (Denmark)

    Dodd, Paul A.; Rabe, Benjamin; Hansen, Edmond

    2012-01-01

    are also the first to show positive fractions of sea ice meltwater at the surface near the core of the EGC. Sections from September 2009–2011 show an increased input of sea ice meltwater at the surface relative to older September sections. This suggests that more sea ice now melts back into the surface...... meltwater inventories, suggesting that meteoric water and brine may be delivered to Fram Strait together from a common source. We find that the freshwater outflow at Fram Strait exhibits a similar meteoric water to net sea ice meltwater ratio as the central Arctic Ocean and Siberian shelves, suggesting......The composition of the Fram Strait freshwater outflow is investigated by comparing 10 sections of concurrent salinity, δ18O, nitrate and phosphate measurements collected between 1997 and 2011. The largest inventories of net sea ice meltwater are found in 2009, 2010 and 2011. The 2009–2011 sections...

  3. Preliminary crustal model from seismological observations at the Messina Straits network

    Directory of Open Access Journals (Sweden)

    B. FEDERICO

    1979-06-01

    Full Text Available Starting from a general tectonic description of the Strait of Messina,
    what follows is an explanation of the criteria adopted in choosing
    sites for seismic stations of the Straits network.
    The main lithological and mechanical characteristics of the terrains
    where the stations are been located, together with the equipment used,
    are mentioned, are looked at in relation to the positions of the main
    centres of seismic activity both actual and in recent past, and to the
    microseismic energy threshold.
    A number of observations regarding the seismic crisis in the Gulf
    of Patti (1978 are analized, with the aim of suggesting a crustal model
    compatible with the area of the Messina Straits.

  4. Preliminary result of 3-D attenuation tomography beneath Sunda Strait and western part of Java

    Science.gov (United States)

    Anshori, Muhajir; Nugraha, Andri Dian; Puspito, Nanang T.

    2017-07-01

    Sunda strait lies in the transition zone of two different subduction system that is almost perpendicular to the subduction in southern Java and oblique subduction in western Sumatra. The series of major disasters such as earthquakes and volcanic eruptions is a manifestation of its tectonic setting complexity. We used selected waveform data from724 earthquakes that occurred around the Sunda strait and western part of Java from 2009 - 2015 recorded by 21 MCGA network stations to construct three dimensional image of seismic attenuation. Frequency independent attenuation operators (t*) was determined using spectral fitting method for P and S wave arrivals, respectively. The inversion was performed using simul2000 algorithm to image the lateral and vertical variations of Qp and Qs value in the Sunda Strait and western part of Java. Some interesting features such as subducting slab, mantle wedge, magma chamber under volcanos and fault zones can be imaged well.

  5. Polycyclic aromatic hydrocarbons in coastal sediment of klang strait, Malaysia: distribution pattern, risk assessment and sources.

    Directory of Open Access Journals (Sweden)

    Seyedeh Belin Tavakoly Sany

    Full Text Available Concentration, source, and ecological risk of polycyclic aromatic hydrocarbons (PAHs were investigated in 22 stations from surface sediments in the areas of anthropogenic pollution in the Klang Strait (Malaysia. The total PAH level in the Klang Strait sediment was 994.02±918.1 µg/kg dw. The highest concentration was observed in stations near the coastline and mouth of the Klang River. These locations were dominated by high molecular weight PAHs. The results showed both pyrogenic and petrogenic sources are main sources of PAHs. Further analyses indicated that PAHs primarily originated from pyrogenic sources (coal combustion and vehicular emissions, with significant contribution from petroleum inputs. Regarding ecological risk estimation, only station 13 was moderately polluted, the rest of the stations suffered rare or slight adverse biological effects with PAH exposure in surface sediment, suggesting that PAHs are not considered as contaminants of concern in the Klang Strait.

  6. POTENTIAL PRODUCTION OF DEMERSAL FISH STOCK IN THE MALACCA STRAIT OF INDONESIA

    Directory of Open Access Journals (Sweden)

    Purwanto Purwanto

    2015-06-01

    Full Text Available Malacca Strait is one of the main fishing areas for demersal fishery in Indonesia. To support the management of that fishery, an assessment of the demersal fish stock was conducted. This study estimated that the maximum sustainable yield and the optimal catch per unit effortof demersal fishery in the Malacca Strait were about 106.8 thousand tons/year and 28.5 tons per unit of Danish seine, respectively, resulting from the operation of 3,752 Danish seines. Unfortunately, fishing effort was higher than its optimum level and the fish stock was over-exploited since 2003. To recover the demersal fish stock to its optimum level and to ensure the optimal fish production from demersal fishery in the Malacca Strait, it was necessary to reduce fishing effort at about 67% from its level in 2011.

  7. Social, occupational and cultural adaptation in Antarctica

    Science.gov (United States)

    Nicolas, Michel; Bishop, Sheryl; Weiss, Karine; Gaudino, Marvin

    2016-07-01

    Life in isolated and confined environments (ICEs, e.g., polar stations, submarine or space missions), is subject to important constraints which can generate psychosociological impaired outcomes. This study investigated psychological, social, occupational and cultural variables which are among the most important determinants in adaptation to a one-year wintering in Antarctica with 13 international participants. Our findings confirm and give further insight into the role of social (Cohesiveness, Social Support) and occupational (Implementation / Preparedness, Counterproductive Activity, Decision Latitude and Psychological Job Demands) dimensions of adaptation to ICE environments. Relationships between various social and occupational dimensions studies reflected detrimental effects ranging from decrements in cohesiveness, social support and work performance which differed across professional status and multicultural factors. These psychosocial issues have important implications for pre-mission selection and training, monitoring and support of crews during the mission and post-mission readaptation. Operational recommendations are suggested to improve adaptation, success and well-being for long-term ICE missions, e.g., to Mars and beyond.

  8. AGB Star Variability Observed from Antarctica

    Science.gov (United States)

    Briguglio, Runa

    2008-04-01

    We present here a short account of the first observations done at the Italo-French base of Dome C, Antarctica, in the field of Mira variability. The observations aimed at improving our knowledge of the variability period of some important Long Period Variables (LPV), to be used in Period-Luminosity criteria for determining in a reliable way the absolute magnitudes and hence the distances of AGB stars. The observations were taken during the 2007 winter campaign, using the small-IRAIT telescope, a 25 cm Cassegrain instrument capable of multiband photometry. The telescope was equipped with a reliable remote control system, which allowed us to get very high duty-cycle observations (the highest efficient was obtained in July 2007, with more than 98% of on-source time, over 9 ``solar'' days during the long polar night). The experiments done with small IRAIT will be precious as a pathfinder, for defining the observational strategies of the larger IRAIT (International Robotic Antarctic Infrared Telescope [1]), an 80-cm aperture telescope, working mainly in IR, that will be installed in Dome C next year.

  9. Phytoplankton Bloom Phenology near Palmer Station Antarctica

    Science.gov (United States)

    Crews, L.; Doney, S. C.; Kavanaugh, M.; Ducklow, H. W.; Schofield, O.; Glover, D. M.

    2015-12-01

    West Antarctic Peninsula (WAP) phytoplankton bloom phenology is coupled to growing season water column stratification precipitated by seasonal warming and the melting of winter sea-ice. Previous studies document declining bloom magnitude over decadal timescales in conjunction with decreasing sea-ice extent and duration in the Northern WAP, but less work has been to done explain the observed inter-annual variability in this region. Here we use a high-resolution in situ time series collected by the Palmer Station Antarctica Long Term Ecological Research program and satellite ocean color imagery to investigate the underlying mechanisms controlling phytoplankton bloom timing and magnitude near Palmer Station. We pair chlorophyll and CTD measurements collected twice per week during the austral summer, 1992—2003, with satellite ocean color and ice fractional cover data to examine bloom development and within-season trends in mixed layer depth. Initial results suggest a possible shift over time with spring/summer blooms occurring earlier in the growing season reflecting earlier sea-ice free conditions. Net phytoplankton accumulation rates are also computed and compared against growth estimates. Our results can be used to develop and validate models of coastal Antarctic primary production that better represent inter-annual primary production variability.

  10. Physical properties of aerosols at Maitri, Antarctica

    Indian Academy of Sciences (India)

    C G Deshpande; A K Kamra

    2004-03-01

    Measurements of the submicron aerosol size distribution made at the Indian Antarctic station, Maitri (70° 45′S, 11° 44′E) from January 10th to February 24th, 1997, are reported. Total aerosol concentrations normally range from 800 to 1200 particles cm-3 which are typical values for the coastal stations at Antarctica in summer. Aerosol size distributions are generally trimodal and open- ended with a peak between 75 and 133nm and two minima at 42 and 420 nm. Size distributions remain almost similar for several hours or even days in absence of any meteorological disturbance. Total aerosol concentration increases by approximately an order of magnitude whenever a low pressure system passes over the station. Based on the evolution of aerosol size-distributions during such aerosol enhancement periods, three types of cases have been identified. The nucleation mode in all three cases has been suggested to result from the photochemical conversion of the DMS emissions transported either by the marine air or by the air from the ice-melt regions around Maitri. Subsidence of midtropospheric air during the weakening of radiative inversion is suggested as a possible source of the nucleation mode particles in the third case. Growth of the nucleation mode particles by condensation, coagulation and/or by cloud processes has been suggested to be responsible for other modes in size distributions.

  11. Ozone profiles above Palmer Station, Antarctica

    Science.gov (United States)

    Torres, Arnold L.; Brothers, George

    1988-01-01

    NASA's Goddard Space Flight Center/Wallops Flight Facility conducted a series of 52 balloon-borne measurements of vertical ozone profiles over the National Science Foundation (NSF) research facility at Palmer Station, Antarctica (64 deg 46 S, 64 deg 3 W) between August 9 and October 24, 1987. High resolution measurements were made from ground level to an average of 10 mb. While much variation was seen in the profile amounts of ozone, it is clear that a progressive depletion of ozone occurred during the measurement period, with maximum depletion taking place in the 17 to 19 km altitude region. Ozone partial pressures dropped by about 95 percent in this region. Shown here are plotted time dependences of ozone amounts observed at 17 km and at arbitrarily selected altitudes below (13 km) and above (24 km) the region of maximum depletion. Ozone partial pressure at 17 km is about 150nb in early August, and has decreased to less than 10nb in the minimums in October. The loss rate is of the order of 1.5 percent/day. In summary, a progressive depletion in stratospheric ozone over Palmer Station was observed from August to October, 1987. Maximum depletion occurred in the 17 to 19 km range, and amounted to 95 percent. Total ozone overburden decreased by up to 50 percent during the same period.

  12. Performance assessment for an operational ocean model of the Taiwan Strait

    Science.gov (United States)

    Lin, Xinyou; Yan, Xiao-Hai; Jiang, Yuwu; Zhang, Zhenchang

    2016-06-01

    The Taiwan Strait Nowcast/Forecast System (TFOR), which is based on the Regional Ocean Modeling System, may be the first operational ocean model to include both tide and circulation processes in the Taiwan Strait. In this study, we assessed the performance of TFOR by investigating the differences between observational data and the results obtained by TFOR, thereby illustrating the ability of TFOR to reproduce significant physical processes. We also evaluated the utility and reliability of TFOR products for successful applications in maritime search and rescue. The mean bias, root mean-squared difference, correlation coefficient (CC), and Willmott skill for the differences in temperature between the cruise observations and the TFOR results were -0.01°C, 1.2°C, 0.87, and 0.92, respectively, and those for the corresponding salinity results were 0.06 PSU, 0.4 PSU, 0.74, and 0.83, respectively. The distributions of the TFOR M2 harmonic constants indicated that TFOR simulates the tidal characteristics well in the Taiwan Strait. The CC between the Taiwan Strait volume transport based on the TFOR results and the along-strait wind stress was 0.77, thereby indicating that monsoon winds exert an important influence on the variability in volume transport through the Taiwan Strait. Statistical analyses of the TFOR results showed that the annual, spring, summer, autumn, and winter mean transport volumes were 1.16, 1.28, 2.52, 0.80, and 0.04 Sv, respectively. In conclusion, the TFOR is robust and it can simulate the temperature, salinity, and velocity in a reasonable and stable manner.

  13. The influence of the Bering Strait on the circulation in a coarse resolution global ocean model

    Science.gov (United States)

    Reason, C. J. C.; Power, S. B.

    1994-05-01

    An ocean general circulation model of global domain, full continental geometry and bottom topography, is used to study the influence of the Bering Strait on the general circulation by comparing equilibrium solutions obtained with and without a land-bridge between Siberia and Alaska. The model is integrated with restoring boundary conditions (BC) on temperature and salinity, and later, with mixed BC in which a restoring BC on temperature is maintained but a specified flux condition on salinity is imposed. In both cases, the effect of the Bering Strait is to allow a flow of about 1.25 1.5 Sv from the North Pacific to the Arctic Ocean and, ultimately, back to the North Pacific along the western boundary current regions of the Atlantic and Indian Oceans. When a restoring BC on salinity is used, the overturning associated with North Atlantic Deep Water and Antarctic Intermediate Water formation are increased if the Bering Strait is present in the model geometry. The result of switching to a specified flux BC on salinity is to cause a transition in the THC in which the overturning associated with North Atlantic Deep Water formation increases from about 12 Sv to about 22 Sv. This transition occurs in an essentially smooth fashion with no significant variability and is about 12% smaller in magnitude if the Bering Strait is present in the model geometry. Because the Bering Strait appears to exert some influence on the general circulation and the formation of deep water masses, it is recommended that this Strait be included in the geometry of similar resolution models designed to study the deep ocean and potential changes in climate.

  14. Flow, waves and water exchange in the Suur Strait, Gulf of Riga, in 2008:

    Directory of Open Access Journals (Sweden)

    Tarmo Kõuts

    2011-03-01

    Full Text Available Wind, flow and wave measurements were performed in November-December in 2008 in the relatively narrowand shallow Suur Strait connecting the waters of the Väinameri and the Gulf of Riga.During the measurement period wind conditions were extremely variable, including a severe storm on 23 November. The flow speedalong the strait varied between ±0.2 m s-1, except for the 0.4 m s-1 that occurred after the storm as a result of the sealevel gradient. The mean and maximum significant wave heights were 0.53 m and 1.6 m respectively. Because of their longer fetch, southerlywinds generated higher waves in the strait than winds from the north. All wave events caused by the stronger southerly windsinduced sediment resuspension, whereas the current-induced shear velocity slightly exceeded the critical value for resuspensiononly when the current speed was 0.4 m s-1. A triple-nested two-dimensional high resolution (100 m in the Suur Strait circulation model and the SWANwave model were used to simulate water exchange in 2008 and the wave-induced shear velocity field in the Suur Strait respectively. Circulation model simulations demonstrated that water exchange was highly variable, that cumulative transport followed an evident seasonal cycle, and that there was an grossannual outflow of 23 km3 from the Gulf of Riga. The horizontal distribution of wave-induced shear velocityduring the strong southerly wind event indicated large shear velocities and substantial horizontal variability. The shearvelocities were less than the critical value for resuspension in the deep area of the Suur Strait.

  15. 45 CFR 674.4 - Restrictions on collection of meteorites in Antarctica.

    Science.gov (United States)

    2010-10-01

    ... Antarctica. 674.4 Section 674.4 Public Welfare Regulations Relating to Public Welfare (Continued) NATIONAL SCIENCE FOUNDATION ANTARCTIC METEORITES § 674.4 Restrictions on collection of meteorites in Antarctica. No person may collect meteorites in Antarctica for other than scientific research purposes....

  16. Description of gravity cores from San Pablo Bay and Carquinez Strait, San Francisco Bay, California

    Science.gov (United States)

    Woodrow, Donald L.; John L. Chin,; Wong, Florence L.; Fregoso, Theresa; Jaffe, Bruce E.

    2017-06-27

    Seventy-two gravity cores were collected by the U.S. Geological Survey in 1990, 1991, and 2000 from San Pablo Bay and Carquinez Strait, California. The gravity cores collected within San Pablo Bay contain bioturbated laminated silts and sandy clays, whole and broken bivalve shells (mostly mussels), fossil tube structures, and fine-grained plant or wood fragments. Gravity cores from the channel wall of Carquinez Strait east of San Pablo Bay consist of sand and clay layers, whole and broken bivalve shells (less than in San Pablo Bay), trace fossil tubes, and minute fragments of plant material.

  17. Satellite estimate of freshwater exchange between the Indonesian Seas and the Indian Ocean via the Sunda Strait

    Science.gov (United States)

    Potemra, James T.; Hacker, Peter W.; Melnichenko, Oleg; Maximenko, Nikolai

    2016-07-01

    The straits in Indonesia allow for low-latitude exchange of water between the Pacific and Indian Oceans. Collectively known as the Indonesian Throughflow (ITF), this exchange is thought to occur primarily via the Makassar Strait and downstream via Lombok Strait, Ombai Strait, and Timor Passage. The Sunda Strait, between the islands of Sumatra and Java, is a very narrow (≈10 km) and shallow (≈20 m) gap, but it connects the Java Sea directly to the Indian Ocean. Flow through this strait is presumed to be small, given the size of the passage; however, recent observations from the Aquarius satellite indicate periods of significant freshwater transport, suggesting the Sunda Strait may play a more important role in Pacific to Indian Ocean exchange. The nature of this exchange is short-duration (several days) bursts of freshwater injected into the eastern Indian Ocean superimposed on a mean seasonal cycle. The mean volume transport is small averaging about 0.1 Sv toward the Indian Ocean, but the freshwater transport is nonnegligible (estimated at 5.8 mSv). Transport through the strait is hydraulically controlled and directly correlates to the along-strait pressure difference. The episodic low-salinity plumes observed by Aquarius do not, however, appear to be forced by this same mechanism but are instead controlled by convergence of flow at the exit of the Strait in the Indian Ocean. Numerical model results show the fate of this freshwater plume varies with season and is either advected to the northwest along the coast of Sumatra or southerly into the ITF pathway.

  18. Where does CO2 in Antarctica cool the atmosphere ?

    Science.gov (United States)

    Schmithüsen, Holger; Notholt, Justus; König-Langlo, Gert; Lemke, Peter; Jung, Thomas

    2016-04-01

    In a recent study we have shown that for the high altitude plateau in Antarctica CO2 causes a surplus in infrared emission to space compared to what is emitted from the surface. This corresponds to a negative greenhouse effect, and is due to the fact that for this region the surface is typically colder than the atmosphere above, opposite to the rest of the world. As a consequence, for this region an increase in CO2 leads to an increase in the energy loss to space, leading to an increase in the negative greenhouse effect. We now studied in more detail the radiative effect of CO2 and compared the results with available measurements from Antarctica. H. Schmithüsen, J. Notholt, G. Köngig-Langlo, T, Jung. How increasing CO2 leads to an increased negative greenhouse effect in Antarctica. Geophysical Research Letters, in press, 2015. doi: 10.1002/2015GL066749.

  19. Provenance of dust to Antarctica: A lead isotopic perspective

    Science.gov (United States)

    Gili, Stefania; Gaiero, Diego M.; Goldstein, Steven L.; Chemale, Farid, Jr.; Koester, Edinei; Jweda, Jason; Vallelonga, Paul; Kaplan, Michael R.

    2016-03-01

    Antarctic ice preserves an ~800 kyr record of dust activity in the Southern Hemisphere. Major efforts have been dedicated to elucidate the origin of this material in order to gain greater insight into the atmospheric dust cycle. On the basis of Pb isotopes in Antarctic dust samples and potential sources, this contribution demonstrates for the first time that Patagonia is the main contributor of dust to Antarctica during interglacial periods as well as glacials, although the potential importance of Tierra del Fuego remains unclear because of its geochemical similarities to Patagonia. An important new finding is that the Puna-Altiplano sector of the continent is a second important dust source to eastern Antarctica during both glacials and interglacials, being more prominent during interglacials. The data indicate South America is the primary dust source to Antarctica during both glacials and interglacials.

  20. Permafrost and periglacial research in Antarctica: New results and perspectives

    Science.gov (United States)

    Guglielmin, Mauro; Vieira, Gonçalo

    2014-11-01

    In the last two years the research within the Antarctic Permafrost, Periglacial Environments and Soils (ANTPAS) Expert Group of the Scientific Committee on Antarctic Research (SCAR) and Working Group of the International Permafrost Association (IPA) provided new results on the dynamics of periglacial environments both in Maritime and Continental Antarctica. In continental Antarctica despite the absence of air warming, in the last 15 years an active layer thickening and acceleration of permafrost degradation erosional phenomena were reported, these being mainly related to the increase of solar radiation. On the other hand, in Maritime Antarctica, with a dramatic air warming, permafrost degradation has been observed, but the role of snow cover on the ground energy balance and consequently on permafrost and active layer has been underlined. Moreover, many contributions on the knowledge on the characteristics of the Antarctic soils were carried out in several areas along a wide latitudinal range.

  1. Ongoing deformation of Antarctica following recent Great Earthquakes

    Science.gov (United States)

    King, Matt; Santamaría-Gómez, Alvaro

    2016-04-01

    The secular motion of Antarctica is thought to be almost everywhere governed by horizontal rigid plate rotation plus three-dimensional deformations due to past and present changes in ice-ocean loading, known as glacial isostatic adjustment (GIA). We use geodetic data to investigate deformation following the 1998 magnitude ~8.1 Antarctic intra-plate Earthquake, and show sustained three-dimensional deformation along East Antarctica's coastline, 600 km from the rupture location. Using a model of viscoelastic deformation we are able to match observed northward velocity changes, and either east or height, but not all three directions simultaneously, apparently partly due to lateral variations in mantle rheology. Our modeling predicts much of Antarctica may still be deforming, with further deformation possible from the 2004 Macquarie Ridge Earthquake. This previously unconsidered mode of Antarctic deformation affects geodetic estimates of plate motion and GIA; its viscous nature raises the prospect of further present-day deformation due to earlier Great Earthquakes.

  2. Molecular Cytogenetic Analysis of Deschampsia antarctica Desv. (Poaceae), Maritime Antarctic.

    Science.gov (United States)

    Amosova, Alexandra V; Bolsheva, Nadezhda L; Samatadze, Tatiana E; Twardovska, Maryana O; Zoshchuk, Svyatoslav A; Andreev, Igor O; Badaeva, Ekaterina D; Kunakh, Viktor A; Muravenko, Olga V

    2015-01-01

    Deschampsia antarctica Desv. (Poaceae) (2n = 26) is one of the two vascular plants adapted to the harshest environment of the Antarctic. Although the species is a valuable model for study of environmental stress tolerance in plants, its karyotype is still poorly investigated. We firstly conducted a comprehensive molecular cytogenetic analysis of D. antarctica collected on four islands of the Maritime Antarctic. D. antarctica karyotypes were studied by Giemsa C- and DAPI/C-banding, Ag-NOR staining, multicolour fluorescence in situ hybridization with repeated DNA probes (pTa71, pTa794, telomere repeats, pSc119.2, pAs1) and the GAA simple sequence repeat probe. We also performed sequential rapid in situ hybridization with genomic DNA of D. caespitosa. Two chromosome pairs bearing transcriptionally active 45S rDNA loci and five pairs with 5S rDNA sites were detected. A weak intercalary site of telomere repeats was revealed on the largest chromosome in addition to telomere hybridization signals at terminal positions. This fact confirms indirectly the hypothesis that chromosome fusion might have been the cause of the unusual for cereals chromosome number in this species. Based on patterns of distribution of the examined molecular cytogenetic markers, all chromosomes in karyotypes were identified, and chromosome idiograms of D. antarctica were constructed. B chromosomes were found in most karyotypes of plants from Darboux Island. A mixoploid plant with mainly triploid cells bearing a Robertsonian rearrangement was detected among typical diploid specimens from Great Jalour Island. The karyotype variability found in D. antarctica is probably an expression of genome instability induced by environmental stress factors. The differences in C-banding patterns and in chromosome distribution of rDNA loci as well as homologous highly repeated DNA sequences detected between genomes of D. antarctica and its related species D. caespitosa indicate that genome reorganization involving

  3. Ice plug prevents irreversible discharge from East Antarctica

    Science.gov (United States)

    Mengel, M.; Levermann, A.

    2014-06-01

    Changes in ice discharge from Antarctica constitute the largest uncertainty in future sea-level projections, mainly because of the unknown response of its marine basins. Most of West Antarctica's marine ice sheet lies on an inland-sloping bed and is thereby prone to a marine ice sheet instability. A similar topographic configuration is found in large parts of East Antarctica, which holds marine ice equivalent to 19 m of global sea-level rise, that is, more than five times that of West Antarctica. Within East Antarctica, the Wilkes Basin holds the largest volume of marine ice that is fully connected by subglacial troughs. This ice body was significantly reduced during the Pliocene epoch. Strong melting underneath adjacent ice shelves with similar bathymetry indicates the ice sheet's sensitivity to climatic perturbations. The stability of the Wilkes marine ice sheet has not been the subject of any comprehensive assessment of future sea level. Using recently improved topographic data in combination with ice-dynamic simulations, we show here that the removal of a specific coastal ice volume equivalent to less than 80 mm of global sea-level rise at the margin of the Wilkes Basin destabilizes the regional ice flow and leads to a self-sustained discharge of the entire basin and a global sea-level rise of 3-4 m. Our results are robust with respect to variation in ice parameters, forcing details and model resolution as well as increased surface mass balance, indicating that East Antarctica may become a large contributor to future sea-level rise on timescales beyond a century.

  4. Abrupt Atmospheric Methane Increases Associated With Hudson Strait Heinrich Events

    Science.gov (United States)

    Rhodes, R.; Brook, E.; Chiang, J. C. H.; Blunier, T.; Maselli, O. J.; McConnell, J. R.; Romanini, D.; Severinghaus, J. P.

    2015-12-01

    The drivers of abrupt climate change during the Last Glacial Period are not well understood. While Dansgaard-Oeschger (DO) cycles are thought to be linked to variations in the strength of the Atlantic Meridional Ocean Circulation (AMOC), it is not clear how or if Heinrich Events—extensive influxes of icebergs into the North Atlantic Ocean that impacted global climate and biogeochemistry—are related. An enduring problem is the difficultly in dating iceberg rafted debris deposits that typically lack foraminifera. Here we present an ultra-high resolution record of methane from the West Antarctic Ice Sheet Divide ice core at unprecedented, continuous temporal resolution from 67.2-9.8 ka BP, which we propose constrains the timing of Heinrich events. Our methane record essentially mirrors Greenland ice core stable isotope variability across D-O events, except during Heinrich stadials 1, 2, 4 and 5. Partway through these stadials only, methane increases abruptly and rapidly, as at the onset of a D-O event but Greenland temperature exhibits no equivalent response. Speleothem records exhibit signatures of drought in the Northern extra-tropics and intensified monsoonal activity over South America at these times. We use a simple heuristic model to propose that cold air temperatures and extensive sea ice in the North, resulting from Heinrich events, caused extreme reorganization of tropical hydroclimate. This involved curtailment of the seasonal northerly migration of tropical rain belts, leading to intensification of rainfall over Southern Hemisphere tropical wetlands, thus allowing production of excess methane relative to a 'normal' Greenland stadial. We note that this mechanism can operate if AMOC is already in a slowed state when a Heinrich event occurs, as paleo-evidence suggests it was. Heinrich events and associated sea ice cover would therefore act to prolong the duration of this AMOC state. Our findings place the big four Heinrich events of Hudson Strait origin

  5. Single-ping ADCP measurements in the Strait of Gibraltar

    Science.gov (United States)

    Sammartino, Simone; García Lafuente, Jesús; Naranjo, Cristina; Sánchez Garrido, José Carlos; Sánchez Leal, Ricardo

    2016-04-01

    In most Acoustic Doppler Current Profiler (ADCP) user manuals, it is widely recommended to apply ensemble averaging of the single-pings measurements, in order to obtain reliable observations of the current speed. The random error related to the single-ping measurement is typically too high to be used directly, while the averaging operation reduces the ensemble error of a factor of approximately √N, with N the number of averaged pings. A 75 kHz ADCP moored in the western exit of the Strait of Gibraltar, included in the long-term monitoring of the Mediterranean outflow, has recently served as test setup for a different approach to current measurements. The ensemble averaging has been disabled, while maintaining the internal coordinate conversion made by the instrument, and a series of single-ping measurements has been collected every 36 seconds during a period of approximately 5 months. The huge amount of data has been fluently handled by the instrument, and no abnormal battery consumption has been recorded. On the other hand a long and unique series of very high frequency current measurements has been collected. Results of this novel approach have been exploited in a dual way: from a statistical point of view, the availability of single-ping measurements allows a real estimate of the (a posteriori) ensemble average error of both current and ancillary variables. While the theoretical random error for horizontal velocity is estimated a priori as ˜2 cm s-1 for a 50 pings ensemble, the value obtained by the a posteriori averaging is ˜15 cm s-1, with an asymptotical behavior starting from an averaging size of 10 pings per ensemble. This result suggests the presence of external sources of random error (e.g.: turbulence), of higher magnitude than the internal sources (ADCP intrinsic precision), which cannot be reduced by the ensemble averaging. On the other hand, although the instrumental configuration is clearly not suitable for a precise estimation of turbulent

  6. Mean thermospheric winds observed from Halley, Antarctica

    Directory of Open Access Journals (Sweden)

    R. I. Crickmore

    Full Text Available Thermospheric winds on a total of 237 nights have been studied for the effects due to geomagnetic activity, solar flux, and season. The observations have been made from 1988 to 1992 by a Fabry-Perot interferometer (FPI operating at Halley (75.5°S, 26.6°W, Antarctica. This is the first statistical study of thermospheric winds near the southern auroral zone. The main factor affecting the wind velocities is the geomagnetic activity. Increases in activity cause an increase in the maximum equatorward wind, and cause the zonal wind in the evening to become more westward. Smaller changes in the mean wind occur with variations in season and solar flux. The small variation with solar flux is more akin to the situation found at mid-latitudes than at high latitudes. Since the geomagnetic latitude of Halley is only 61°, it suggests that the variability of the wind with solar flux may depend more on geomagnetic than geographic latitude. These observations are in good agreement with the empirical Horizontal Wind Model (HWM90. However, comparisons with predictions of the Vector Spherical Harmonic Model (VSH show that for low geomagnetic activity the predicted phases of the two components of the wind closely resemble the observations but the modelled amplitudes are too small by a factor of two. At high geomagnetic activity the major differences are that modelled zonal velocity is too westward in the evening and too eastward after 04 UT. The modelled ion densities at the F-region peak are a factor of up to 9 too large, whilst the predicted mean value and diurnal variation of the altitude of the peak are significantly lower than those observed. It is suggested that these differences result from the ion loss rate being too low, and an inaccurate model of the magnetic field.

  7. Soils of Marie Byrd Land, West Antarctica

    Science.gov (United States)

    Lupachev, A. V.; Abakumov, E. V.

    2013-10-01

    Soils of Marie Byrd Land-one of the remotest and difficultly accessible regions of Antarctica-were investigated in the area of the mothballed Russkaya station located to the south of 74° S. Despite the extremely severe wind regime (the average wind velocity is 13 m/s, and the maximum wind velocity is up to 60 m/s), the projective cover of vegetation in the area of the station averages 25-40% and reaches 60-80% in some places. The phenomena of physical weathering of the bedrock-exfoliation, stone pavements, residual rocks exposed by wind (hoodoos), and others-are clearly manifested. In most of the described soils, normal organic and organomineral horizons are absent. The soil profiles represent the mixture of the residues of mosses and lichens and the gravelly eluvium. The fine earth material is blown out of the surface horizons by strong winds; its residual accumulation takes place in the middle and lower parts of the profiles. The classification position of these soils is open to argument; they are close to Petrozems and Lithozems. Most of the profiles are underlain by the massive or slightly disintegrated bedrock with dry permafrost at a depth of 20 to 50 cm. Soils with dry permafrost comprise about 75% of the surveyed area. In separate loci in the depressions of the local mesorelief and on gentle slopes, the soils with clearly expressed cryoturbation features are developed; their profiles are underlain by the ice-rich permafrost and compose about 15% of the surveyed area. Anthropogenically disturbed soils and soils polluted with petroleum hydrocarbons, heavy metals, and other pollutants occupy about 10% of the surveyed area.

  8. Electric field measurements from Halley, Antarctica

    Science.gov (United States)

    Nicoll, Keri; Harrison, R. Giles

    2016-04-01

    Antarctica is a unique location for the study of atmospheric electricity. Not only is it one of the most pollutant free places on Earth, but its proximity to the south magnetic pole means that it is an ideal location to study the effects of solar variability on the atmospheric electric field. This is due to the reduced shielding effect of the geomagnetic field at the poles which leads to a greater flux of incoming Galactic Cosmic Rays (GCRs) as well as an increased probability of energetic particle precipitation from SEPs and relativistic electrons. To investigate such effects, two electric field mills of different design were installed at the British Antarctic Survey Halley base in February 2015 (75. 58 degrees south, 26.66 degrees west). Halley is situated on the Brunt Ice Shelf in the south east of the Weddell Sea and has snow cover all year round. Preliminary analysis has focused on selection of fair weather criteria using wind speed and visibility measurements which are vital to assess the effects of falling snow, blowing snow and freezing fog on the electric field measurements. When the effects of such adverse weather conditions are removed clear evidence of the characteristic Carnegie Curve diurnal cycle exists in the Halley electric field measurements (with a mean value of 50V/m and showing a 40% peak to peak variation in comparison to the 34% variation in the Carnegie data). Since the Carnegie Curve represents the variation in thunderstorm activity across the Earth, its presence in the Halley data confirms the presence of the global atmospheric electric circuit signal at Halley. The work presented here will discuss the details of the Halley electric field dataset, including the variability in the fair weather measurements, with a particular focus on magnetic field fluctuations.

  9. Carbon flows in the benthic food web at the deep-sea observatory HAUSGARTEN (Fram Strait)

    NARCIS (Netherlands)

    Van Oevelen, D.; Bergmann, M.; Soetaert, K.E.R.; Bauerfeind, E.; Hasemann, C.; Klages, M.; Schewe, I.; Soltwedel, T.; Budaeva, N.E.

    2011-01-01

    The HAUSGARTEN observatory is located in the eastern Fram Strait (Arctic Ocean) and used as long-term monitoring site to follow changes in the Arctic benthic ecosystem. Linear inverse modelling was applied to decipher carbon flows among the compartments of the benthic food web at the central

  10. Water mass of the northward throughflow in the Bering Strait in the summer of 2003

    Institute of Scientific and Technical Information of China (English)

    ZHAO Jinping; SHI Jiuxin; GAO Guoping; JIAO Yutian; ZHANG Hongxin

    2006-01-01

    The temperature and salinity data obtained by the Chinese national arctic research expedition (CHINARE2003) are used to study the water structure in the Bering Strait and ambient regions. Four water masses appeared in the research region: the intermediate Bering Sea water mass (IBWM), the Alaska coastal water (ACW), the Anadyr water (AW) and the Bering shelf water (BSW). The AW originates from the IBWM, but the upper layer water has been greatly altered. In the cruise on 28/29 July 2003, there were only the BSW and ACW in a section across the Bering Strait (BS section), but in the September 12/13 cruise, the AW, BSW and ACW flowed parallelly into the Bering Strait. The upper waters of these water masses were all altered due to ice melting, runoff, solar radiation, and wind mixing. The waters in the central and northern parts of Bering Strait stratified by two uniform layers,were expressed as the typical feature of the water masses originating from the pacific. A two-layer structure also dominated the vertical stratification in most part of the Chukchi Sea. An obvious subseasonal variation was observed in the BS section, which caused varying transportation of fresh water,heat, and substance, and produced a long-term and extensive impact on the Arctic Ocean.

  11. 33 CFR 100.1307 - Special Local Regulations, Strait Thunder Performance, Port Angeles, WA.

    Science.gov (United States)

    2010-07-01

    ... Thunder Performance, Port Angeles, WA. 100.1307 Section 100.1307 Navigation and Navigable Waters COAST... § 100.1307 Special Local Regulations, Strait Thunder Performance, Port Angeles, WA. (a) Regulated Areas... located near Port Angeles, Washington: Point 1: 48°07′24″ N, 123°25′32″ W; Point 2: 48°07′26″ N,...

  12. Too Distant Shores: The Strait of Gibraltar and the Space of Exception

    Science.gov (United States)

    Gluhovic, Milija

    2008-01-01

    Focusing on "The Sheep and the Whale" ("Le mouton et la baleine," 2001) by Moroccan-Canadian playwright Ahmed Ghazali, this essay examines political and ethical issues concerning human migration from Africa to Europe. The play's representation of human rights abuses in the Strait of Gibraltar and the dilemmas facing illegal…

  13. Plumularian hydroids (Cnidaria: Hydrozoa) from the Strait of Gibraltar and nearby areas

    NARCIS (Netherlands)

    Medel, M.D.; Vervoort, W.

    1995-01-01

    Twenty-four species of plumularian hydroids (Cnidaria: Hydrozoa) from the Strait of Gibraltar area are described and figured, including material from the coasts of southern Spain (between El Portil near the Spanish-Portuguese border and Adra, Mediterranean coast of Granada, c. 3°W) and from Ceuta in

  14. A particle-tracking model for simulating pollutant dispersion in the Strait of Gibraltar.

    Science.gov (United States)

    Periáñez, R

    2004-10-01

    A particle-tracking model to simulate the dispersion of contaminants in the Strait of Gibraltar has been developed. The model solves the hydrodynamic equations off-line and tidal analysis is carried out to determine tidal constants for the two main constituents. Tidal constants and residuals are stored in files that are read by the dispersion model. A lagrangian approach is used to solve dispersion; diffusion and decay are simulated by a Monte Carlo method. A method for assessing the areas of the Strait with higher probability of being affected by contamination occurring after an accident in the shipping routes is given. Generally speaking, the fate of a pollutant discharge strongly depends on wind conditions. Winds from the east tend to retain contamination into the Strait. As a consequence, transverse mixing occurs and both Spain and Morocco coasts are affected by contamination. Under calm conditions and west winds, contaminants are flushed out of the Strait faster and transverse mixing does not occur. Thus, only part of Morocco coast has a higher probability of being affected by contamination.

  15. The family Haleciidae (Cnidaria: Hydrozoa) from the Strait of Gibraltar and nearby areas

    NARCIS (Netherlands)

    Medel, M.D.; García, F.G.; Vervoort, W.

    1998-01-01

    A faunistic study of the family Haleciidae from the Strait of Gibraltar and nearby areas has been made; seven species are described, figured and discussed. Information about the zoogeographical distribution, and conditions of substrates are contributed. A key to distinguish the species of this famil

  16. 76 FR 21330 - Lynn Canal/Icy Straits Resource Advisory Committee

    Science.gov (United States)

    2011-04-15

    ...The Lynn Canal/Icy Straits Resource Advisory Committee will meet in Juneau, Alaska, April 25, 2011. The purpose of this meeting is to orient the new appointees as to the Secure Rural Schools and Community Self-Determination Act of 2008, provide operational guidelines, discuss and adopt specific bylaws for the RAC, and elect a RAC...

  17. Indigenous Language Learning and Maintenance among Young Australian Aboriginal and Torres Strait Islander Children

    Science.gov (United States)

    Verdon, Sarah; McLeod, Sharynne

    2015-01-01

    Internationally, cultural renewal and language revitalisation are occurring among Indigenous people whose lands were colonised by foreign nations. In Australia, the Aboriginal and Torres Strait Islander people are striving for the re-voicing of their mother tongue and the re-practicing of their mother culture to achieve cultural renewal in the…

  18. Plumularian hydroids (Cnidaria: Hydrozoa) from the Strait of Gibraltar and nearby areas

    NARCIS (Netherlands)

    Medel, M.D.; Vervoort, W.

    1995-01-01

    Twenty-four species of plumularian hydroids (Cnidaria: Hydrozoa) from the Strait of Gibraltar area are described and figured, including material from the coasts of southern Spain (between El Portil near the Spanish-Portuguese border and Adra, Mediterranean coast of Granada, c. 3°W) and from Ceuta in

  19. The family Haleciidae (Cnidaria: Hydrozoa) from the Strait of Gibraltar and nearby areas

    NARCIS (Netherlands)

    Medel, M.D.; García, F.G.; Vervoort, W.

    1998-01-01

    A faunistic study of the family Haleciidae from the Strait of Gibraltar and nearby areas has been made; seven species are described, figured and discussed. Information about the zoogeographical distribution, and conditions of substrates are contributed. A key to distinguish the species of this famil

  20. Carbon flows in the benthic food web at the deep-sea observatory HAUSGARTEN (Fram Strait)

    NARCIS (Netherlands)

    Van Oevelen, D.; Bergmann, M.; Soetaert, K.E.R.; Bauerfeind, E.; Hasemann, C.; Klages, M.; Schewe, I.; Soltwedel, T.; Budaeva, N.E.

    2011-01-01

    The HAUSGARTEN observatory is located in the eastern Fram Strait (Arctic Ocean) and used as long-term monitoring site to follow changes in the Arctic benthic ecosystem. Linear inverse modelling was applied to decipher carbon flows among the compartments of the benthic food web at the central HAUSGAR

  1. Report on the Hydroida collected by the "BALGIM" expedition in and around the Strait of Gibraltar

    NARCIS (Netherlands)

    Ramil, F.; Vervoort, W.

    1992-01-01

    A total of 102 species and varieties of hydroids and three unidentifiable species are described or mentioned in the present report, which deals principally with hydroids collected in the IberoMoroccan Bay (and adjacent Atlantic), the Strait of Gibraltar, and the Alboran Sea; for revisionary purposes

  2. Hydraulic theory of sea straits applied to the onset of the Messinian Salinity Crisis

    NARCIS (Netherlands)

    Meijer, P.Th.

    2012-01-01

    Theory for the dynamics of flow in sea straits holds promise to provide, in addition to geological evidence, insight into the configuration of the connection between the Mediterranean Sea and the Atlantic Ocean at the onset of the Messinian Salinity Crisis. This paper, for the first time, systematic

  3. Indigenous Language Learning and Maintenance among Young Australian Aboriginal and Torres Strait Islander Children

    Science.gov (United States)

    Verdon, Sarah; McLeod, Sharynne

    2015-01-01

    Internationally, cultural renewal and language revitalisation are occurring among Indigenous people whose lands were colonised by foreign nations. In Australia, the Aboriginal and Torres Strait Islander people are striving for the re-voicing of their mother tongue and the re-practicing of their mother culture to achieve cultural renewal in the…

  4. The Competition of Tidal Mixing and Freshwater Forcing in Shaping the Outflow from Hudson Strait

    Science.gov (United States)

    2011-04-01

    Strait outflow. Journal of Marine Systems , special issue on Hudson Bay, in press. St. Laurent, P., F. Straneo, J.F. Dumais, D.G. Barber, 2011 What...is the fate of the river waters of Hudson Bay? Journal of Marine Systems , special issue on Hudson Bay, in press. Straneo, F., D. Sutherland, D

  5. Managing Stability in the Taiwan Strait: Non-Military Policy towards Taiwan under Hu Jintao

    Directory of Open Access Journals (Sweden)

    Wu-ueh Chang

    2009-10-01

    Full Text Available China’s Taiwan policy has been one of coupling intimidation (the “stick” approach with coercion (the “carrot” approach, a policy mix which, in the near term, is not likely to change, as is evidenced by the passage of the “Anti-Secession Law” in March, 2005. However, under Hu Jintao, the focus has been on pragmatism. The warm atmosphere that presently reigns in the Taiwan Strait area is unprecedented. Further talks are expected before the two cross-Strait leaders are slated to step down, simultaneously, in 2012. An era of reconciliation and negotiations has dawned. For the first time there is consensus regarding norms of interaction between the two sides. Cross-Strait relations have stabilized after years of tumult. More open, stable and predictable cross-Strait relations are in the interests of both sides. Difficulties surely lie ahead, but they will be dealt with in a different manner than what has been witnessed in the past.

  6. The Hormuz Strait Dam Macroproject— 21st Century Electricity Development Infrastructure Node (EDIN)?

    NARCIS (Netherlands)

    Schuiling, R.D.; Badescu, V.; Cathcart, R.B.; Overveld, P.A.L.C.

    2005-01-01

    Ocean gulfs offer a means of artificially creating a depression, which can be used for a regionally significant hydroelectric macroproject. We examine here the case for a dam at the Strait of Hormuz that blocks a large gulf situated in an arid region. A 35 m evaporation of this concentration basin

  7. Report on the Hydroida collected by the "BALGIM" expedition in and around the Strait of Gibraltar

    NARCIS (Netherlands)

    Ramil, F.; Vervoort, W.

    1992-01-01

    A total of 102 species and varieties of hydroids and three unidentifiable species are described or mentioned in the present report, which deals principally with hydroids collected in the IberoMoroccan Bay (and adjacent Atlantic), the Strait of Gibraltar, and the Alboran Sea; for revisionary purposes

  8. Too Distant Shores: The Strait of Gibraltar and the Space of Exception

    Science.gov (United States)

    Gluhovic, Milija

    2008-01-01

    Focusing on "The Sheep and the Whale" ("Le mouton et la baleine," 2001) by Moroccan-Canadian playwright Ahmed Ghazali, this essay examines political and ethical issues concerning human migration from Africa to Europe. The play's representation of human rights abuses in the Strait of Gibraltar and the dilemmas facing illegal migrants, refugees and…

  9. Last Glacial - Holocene stratigraphic development at the Marmara Sea exit of the Bosphorus Strait, Turkey

    Science.gov (United States)

    Köprülü, Kerem; Alpar, Bedri; Vardar, Denizhan

    2016-03-01

    High resolution Chirp and Sparker data allowed definition and mapping of distinct seismic units in the shallow sediment record (~100 ms) acquired from the southern exit of the Bosphorus Strait; a dynamic depositional environment. The bottommost unit observed in the Chirp data (unit-3) is made up of marine-lacustrine sediments thinning seaward and onlaps the basement rocks which are represented by folded strata in the Sparker data, possibly lower to middle Pleistocene age. It is overlain by a series of prograding deposits along the shelf (unit-2) referring to sediment input from the northern sector depending on the water levels of the paleo Marmara lake's during MIS 3. The uppermost deposits (unit-1) close to the Bosphorus Strait were represented by three separate subunits, unlike to relatively thin drape of sediments observed at the other places in the surrounding regions. The detailed definition of these subunits deduced from the closely-spaced reflection profiles and available radiocarbon ages helped to explain the history of the latest stratigraphic development depending on the connections between the Black Sea and the Sea of Marmara. In addition to the previously proposed major conduits, which controlled the sedimentary deposition at the southern exit of the Bosphorus, namely the Bosphorus Strait and Kurbağalıdere River, another submarine sedimentary pathway at the eastern bank of the strait's channel seems to have delivered sediments directly into the basin.

  10. Too Distant Shores: The Strait of Gibraltar and the Space of Exception

    Science.gov (United States)

    Gluhovic, Milija

    2008-01-01

    Focusing on "The Sheep and the Whale" ("Le mouton et la baleine," 2001) by Moroccan-Canadian playwright Ahmed Ghazali, this essay examines political and ethical issues concerning human migration from Africa to Europe. The play's representation of human rights abuses in the Strait of Gibraltar and the dilemmas facing illegal…

  11. Genetic relationship of Sardinella lemuru from lombok strait with fish rich in omega-3 fatty acid.

    Science.gov (United States)

    Mahrus; Sumitro, Sutiman Bambang; Utomo, Didik Huswo; Sartimbul, Aida; Toha, Abdul Hamid; Widodo, Nashi

    2012-01-01

    Lombok Strait has abundance of Sardine, Sardinella lemuru, which contains such high amount of omega-3 fatty acid (omega-3). However, the genetic relationship of S. lemuru with other commercial fish rich in omega-3 has not been widely studied yet. Studies on genetic proximity of S. lemuru with the other marine fish using 12S rRNA gene is very important in order to obtain genetic information of the Sardine to develop an appropriate strategy for future conservation of the fish in Lombok Strait. The aim of this study was to find out the genetic relationship of Sardinella lemuru living in Lombok Strait with the economically valuable fish and its correlation with omega-3 production. Sardinella lemuru were collected from Lombok Strait, the phylogenetic tree was done based on 12S rRNA gene through a neighbor-joining method to identify the relationship of Sardines and fish rich in omega-3 fatty acid. The phylogenetic tree showed that Sardinella lemuru is similar to Sardinella aurita and has a close similarity with Sardinella maderensis. However, the relationship did not correspond to omega-3 production. Based on the results of the study, it is suggested that the production of omega-3 is not specifically based on the proximity of the species, but it is more associated with conserved domain of Δ6-desaturase. Nevertheless, detailed mechanisms still need to be elucidated.

  12. Invasive pneumococcal disease in New South Wales, Australia: reporting Aboriginal and Torres Strait Islander status improves epidemiology

    Directory of Open Access Journals (Sweden)

    David N Durrheim

    2011-07-01

    Full Text Available The aim of this work was to determine the feasibility of improving Aboriginal and Torres Strait Islander status recording for notifiable diseases using all Invasive Pneumococcal Disease (IPD notifications in a regional area of New South Wales, Australia.In Australia people with IPD are nearly always admitted to hospital and their Aboriginal and Torres Strait Islander status is recorded. Aboriginal and Torres Strait Islander status was determined for IPD notifications by referring to the routine hospital admission data, in a regional area of New South Wales, Australia.There were 234 notifications in the regional area of Hunter New England during the period 2007–2009. Initially, 168 (72% notifications had Aboriginal and Torres Strait Islander status recorded. After referring to the routine hospital admission data the recorded status increased to 232 (99%. Updating the surveillance data required less than five minutes per notification.Referring to routine hospital admission data proved a useful and time-efficient surveillance strategy to increase the proportion of notifications with Aboriginal and Torres Strait Islander status. These data can then be used to better understand the current epidemiology of IPD. Aboriginal and Torres Strait Islander children aged 0–4 years have a two- to threefold higher rate of invasive pneumococcal disease than non-Aboriginal children, thus high levels of timely pneumococcal immunization coverage remain important for young Aboriginal and Torres Strait Islander children.

  13. Seasonal variability of phytoplankton fluorescence in relation to the Straits of Messina (Sicily tidal upwelling

    Directory of Open Access Journals (Sweden)

    F. Azzaro

    2007-05-01

    Full Text Available In the Straits of Messina the large gradients of tidal displacements as well as the topographic constrictions determine the upwelling of deeper waters in the surface layer. This work describes the seasonal variability of surface distribution of phytoplankton biomass depending on upwelling phenomena. Temperature, salinity, nitrates and phytoplankton fluorescence were measured in 1994 and 1995 by continuous underway surface real-time measurements on board dedicated research boats. Each survey was performed following the dynamic phases of flooding and ebbing tides. Tidal currents are essentially southward during the high tide and northward during the low tide.

    During the low water slack, large spatial gradients of physical-chemical and biological parameters were mainly found, while in the high water slack a diffused phytoplankton fluorescence was observed only in autumn, in coincidence of a seasonal thermocline. Salinity, nitrate and chlorophyll-a fluorescence data revealed a significant positive intercorrelation, whereas they are inversely correlated with temperature. Generally, during winter, the upwelling distribution was limited to narrow zones, while in summer it involved the middle of the Straits and southern zones. During spring in the southern zone of the Straits, maximum of chlorophyll-a fluorescence was detected (May 1995, 0.32 µg-Chla l-1; in summer, when back and forth tidal movements become intense between the Tyrrhenian and the Ionian seas, values was everywhere lower.

    The data set from continuous and repeatable acquisition has allowed the study of different time-space scales in the Straits of Messina, a very strong dynamic environment.

    The Straits system can be compared to an "intermittent pump" which, during the different seasons, before enriched itself and then it provides nutrients to the surrounding basins.

  14. Anthropogenic and natural CO2 exchange through the Strait of Gibraltar

    Directory of Open Access Journals (Sweden)

    J. Ruíz

    2009-01-01

    Full Text Available The exchange of both anthropogenic and natural inorganic carbon between the Atlantic Ocean and the Mediterranean Sea through Strait of Gibraltar was studied for a period of two years under the frame of the CARBOOCEAN project. A comprehensive sampling program was conducted, which was design to collect samples at eight fixed stations located in the Strait in successive cruises periodically distributed through the year in order to ensure a good spatial and temporal coverage. As a result of this monitoring, a time series namely GIFT (GIbraltar Fixed Time series has been established, allowing the generation of an extensive data set of the carbon system parameters in the area. Data acquired during the development of nine campaigns were analyzed in this work. Total inorganic carbon concentration (CT was calculated from alkalinity-pHT pairs and appropriate thermodynamic relationships, with the concentration of anthropogenic carbon (CANT being also computed. Applying a two-layer model of water mass exchange through the Strait and using the transport of the outflowing Mediterranean water recorded in situ during the considered period, a net export of inorganic carbon from the Mediterranean Sea to the Atlantic was obtained, which amounted to 0.025 Pg C yr−1. In contrast, the Atlantic water was found to contain a higher concentration of anthropogenic carbon than the Mediterranean water, resulting in a net flux of CANT towards the Mediterranean basin of 4.2 Tg C yr−1. A carbon balance through the Strait was assessed and fluxes are discussed in relation to the highly diverse estimates available in the literature for the area. This work unequivocally confirms the relevant role of the Strait of Gibraltar as a controlling point for the biogeochemical exchanges occurring between the Mediterranean Sea and the Atlantic Ocean and emphasizes the influence of the Mediterranean basin in the carbon inventories of the North Atlantic.

  15. Geological Features Inferred from Local Seismic Tomography in the Sunda Strait and West Java regions, Indonesia

    Science.gov (United States)

    Nugraha, A. D.; Sakti, A. P.; Rohadi, S.; Widiyantoro, S.

    2012-12-01

    We have conducted seismic tomographic inversions to obtain a P-wave seismic velocity structure beneath the Sunda Strait and West Java regions, Indonesia. The Sunda Strait is located in a complex geological system i.e. in the transition from the oblique subduction beneath Sumatra to the nearly perpendicular subduction below Java. The Krakatau active volcano is located in the Sunda Strait. In this study, we have used selected P-wave arrival times from the data catalogs of the SeisComP-BMKG network (from 2009 to 2011) and the BMKG BALAI II network (from 1992 to 2011) compiled by Badan Meteorologi,Klimatologi dan Geofisika (BMKG), Indonesia. In total, there are 1,598 local earthquakes and 10,366 P-wave phases from 25 seismographic stations that have been used for the tomographic inversions. We have also relocated the hypocenter locations along with velocity inversions simultaneously. Our preliminary results depict some prominent geological features that include: (1) a low velocity anomaly beneath north of the Ujung Kulon region, which coincides with a low gravity anomaly resulting from a previous study, (2) a low velocity anomaly alignment beneath the Krakatau volcano in the Sunda Strait, (3) a sharp contrast in velocity anomalies extending from Pelabuhan Ratu towards Jakarta with a strike of SW-NE, and (4) a low velocity anomaly in the offshore of Pelabuhan Ratu that may be correlated with the continuation of the Cimandiri fault zone. More detailed information will be presented during the meeting. Keywords: tomography, Sunda Strait, West Java, velocity anomaly

  16. Geodiversity of a large meander bend in the Little Belt strait in the inner Danish waters

    Science.gov (United States)

    Brandbyge Ernstsen, Verner; Øbro Hansen, Lars; Becker, Marius; Brivio, Lara; Vang, Torben; Lynnerup Trinhammer, Per; Andresen, Katrine Juul; Seidenkrantz, Marit-Solveig; Boldreel, Lars Ole; Bartholdy, Jesper

    2017-04-01

    The Little Belt strait in the inner Danish waters is characterised by a high biodiversity, and continuous monitoring of flora and fauna and the water quality is undertaken by the authorities. However, the surface sedimentology and geomorphology, i.e. elements of the geodiversity, are less well-constrained. The aim of this study is to investigate the surface sediment and morphology of a large meander bend (with a channel width of 1 km) located between the two bridges crossing the strait (a channel reach of 4 km) in order to assess a potential coupling between geodiversity and biodiversity. More specifically, the objectives are 1) to identify and classify morphological units for creating a geomorphological map, 2) to quantify surface material characteristics for creating a surface material map, and 3) to develop a conceptual model of the substrate and the morphology and morphodynamics in the meander bend between the two bridges in the strait. Preliminary results reveal a diverse morphology in the meander bend; and the annual morphological changes reveal complex sediment transport patterns along and across the bend. Likewise significant sediment sorting trends exist along and across the meander bend. Hence, the preliminary results indicate a high geodiversity in the strait. Acknowledgements The data were collected as part of the MSc course Marine Geoscience, a joint MSc course between the Department of Geosciences and Natural Resource Management at the University of Copenhagen and the Department of Geoscience at Aarhus University. Additional data were included from the research project Control in the Danish Straits 1 (CiDS-1) funded by the Danish Centre for Marine Research (PI Morten Holtegaard). Thanks to the crew on board RV Aurora.

  17. Introduced marine species: Management arrangements of consideration for the Torres Strait

    Science.gov (United States)

    Neil, Kerry M.; Hilliard, Robert; Russell, Barry; Clark, Paul

    2008-09-01

    Introduced marine species (IMS) can have significant impacts on economic, ecological, social and cultural aspects of coastal marine environments. There is, therefore, a need to minimise these impacts through the implementation of comprehensive and consistent management strategies and monitoring processes that work towards preventing introductions, detecting introductions if they were to occur and managing incursions should they be detected. There is also the need to ensure that approaches taken are comparable to provide consistency of IMS management effort, particularly across areas that are multi-jurisdictional (e.g. spanning State or Territory borders). A number of studies have examined IMS, their vectors and management arrangements for the Torres Strait region, a multi-jurisdictional area between Queensland, Australia and Papua New Guinea. This paper presents information from a baseline survey conducted in the Torres Strait for marine pests in conjunction with a synthesis of information from other studies on IMS risks, their vectors and management strategies of relevance to the Torres Strait region. A number of strengths, but also gaps, between the various jurisdictions have been identified and discussed. Processes such as the establishment of Biosecurity Queensland as a specialist group and the development of the National System for the Prevention and Management of Marine Pest Incursions are occurring. However, the Torres Strait region is at current risk of marine pest inoculation, particularly for species such as Perna viridis, and management strategies to minimise this risk are lacking. The information presented here will assist management groups in their ability to work towards mitigating the risk of an IMS being translocated to and negatively impacting the unique and diverse ecology of the marine systems, and the industries, people and customs that rely on the coastal marine environment for food, recreation and commerce in the Torres Strait.

  18. The Holocene history of Nares Strait: Transition from glacial bay to Arctic-Atlantic throughflow

    Science.gov (United States)

    Jennings, Anne E.; Sheldon, Christina; Cronin, Thomas M.; Francus, Pierre; Stoner, Joseph; Andrews, John

    2011-01-01

    Retreat of glacier ice from Nares Strait and other straits in the Canadian Arctic Archipelago after the end of the last Ice Age initiated an important connection between the Arctic and the North Atlantic Oceans, allowing development of modern ocean circulation in Baffin Bay and the Labrador Sea. As low-salinity, nutrient-rich Arctic Water began to enter Baffin Bay, it contributed to the Baffin and Labrador currents flowing southward. This enhanced freshwater inflow must have influenced the sea ice regime and likely is responsible for poor calcium carbonate preservation that characterizes the Baffin Island margin today. Sedimentologic and paleoceanographic data from radiocarbon-dated core HLY03-05GC, Hall Basin, northern Nares Strait, document the timing and paleoenvironments surrounding the retreat of waning ice sheets from Nares Strait and opening of this connection between the Arctic Ocean and Baffin Bay. Hall Basin was deglaciated soon before 10,300 cal BP (calibrated years before present) and records ice-distal sedimentation in a glacial bay facing the Arctic Ocean until about 9,000 cal BP. Atlantic Water was present in Hall Basin during deglaciation, suggesting that it may have promoted ice retreat. A transitional unit with high ice-rafted debris content records the opening of Nares Strait at approximately 9,000 cal BP. High productivity in Hall Basin between 9,000 and 6,000 cal BP reflects reduced sea ice cover and duration as well as throughflow of nutrient-rich Pacific Water. The later Holocene is poorly resolved in the core, but slow sedimentation rates and heavier carbon isotope values support an interpretation of increased sea ice cover and decreased productivity during the Neoglacial period.

  19. Seasonal variability of phytoplankton fluorescence in relation to the Straits of Messina (Sicily) tidal upwelling

    Science.gov (United States)

    Azzaro, F.; Decembrini, F.; Raffa, F.; Crisafi, E.

    2007-10-01

    In the Straits of Messina, large gradients of tidal displacements, as well as the topographic constrictions, determine the upwelling of deeper waters in the surface layer. This work describes the seasonal variability in the surface distribution of phytoplankton biomass depending on the upwelling phenomena. Temperature, salinity, nitrates and phytoplankton fluorescence were measured in 1994 and 1995 by continuous underway surface real-time measurements onboard dedicated research boats. Each survey was performed following the dynamic phases of flooding and ebbing tides. Tidal currents are essentially southward during high tide and northward during low tide. During the low water slack tide, large spatial gradients of physical-chemical and biological parameters were found, while at the high water slack tide, a diffused phytoplankton fluorescence was observed only in autumn due to a seasonal thermocline. Salinity, nitrate and chlorophyll-a fluorescence data revealed a significant positive intercorrelation, whereas they were inversely correlated with temperature. Generally, the upwelling distribution was limited to narrow zones during winter, while in summer it was found in the middle of the Straits and in the southern zones. During spring in the southern zone of the Straits, the maximum chlorophyll-a fluorescence was detected (May 1995, 0.32 μg-Chla l-1); in summer, when back and forth tidal movements between the Tyrrhenian and the Ionian seas intensify, decreased values were observed throughout the study area. The data set obtained through continuous and repeatable samplings has allowed the study of different time-space scales in the Straits of Messina, a very strong and dynamic environment. The Straits system could be compared to an "intermittent pump" which, during the different seasons, initially enriches itself and subsequently provides nutrients to the surrounding basins.

  20. The Two Branches of the Recirculation of Atlantic Water in Fram Strait

    Science.gov (United States)

    von Appen, Wilken-Jon; Schauer, Ursula; Hattermann, Tore; Albretsen, Jon

    2016-04-01

    The Fram Strait between Greenland and Svalbard is one of the two gateways by which warm Atlantic Water enters the Arctic Ocean providing oceanic heat. The West Spitsbergen Current advects the warm water northward in the eastern Fram Strait. However, only some of this water stays in the boundary current and enters the Arctic Ocean. Another part leaves the boundary current and flows westward across Fram Strait before turning southward in the East Greenland Current. This recirculation of Atlantic Water corresponds with the ice edge in Fram Strait and the two likely depend on each other. Here we present results from a high resolution regional numerical model that shows the recirculation to consist of two branches. The northern branch depends on eddy fluxes while the southern branch exhibits less high frequency variability. We also present a compilation of different observational data in the center of Fram Strait around 0°EW that give insight into the structure of the southern recirculation branch near the ice edge. A glider section resolves the small horizontal scale over which the geostrophic flow occurs. Several meridional CTD sections capture the differences and similarities between different summers. Moorings and Argo floats provide information in winter as well. These observations are compared to the representation of the recirculation in the numerical model. We show that the southern recirculation occurs over a small horizontal distance of about 20km in the vicinity of 79°N and is significantly stronger in winter than in summer. While there is cold freshwater at the surface north of the front, the temperature down to 500m is much higher in the recirculation than further south.

  1. Mediterranean waters along and across the Strait of Gibraltar, characterization and zonal modification

    Science.gov (United States)

    Naranjo, Cristina; Sammartino, Simone; García-Lafuente, Jesús; Bellanco, María J.; Taupier-Letage, Isabelle

    2015-11-01

    Hydrological data collected in the Strait of Gibraltar have been used to examine the distribution and spatial-temporal evolution of the water masses in the area. The spatial variability has been addressed by means of a clustering method that determines the affinity of a collection of temperature-salinity samples to one of the water masses involved in the exchange. The method, which has been applied to a nearly-synoptic data set, highlights the clear evolution of the Mediterranean Waters as they flow westward through the Strait. While up to four different Mediterranean Waters are spatially distinguishable east of the main sill of Camarinal in the Strait, most of their differentiating characteristics are eroded after flowing over this restrictive topography due to mixing. West of the sill, therefore, speaking of a unique Mediterranean Water seems more appropriate. The same applies to the North Atlantic Central Water flowing in the opposite direction, which is noticeably modified along its path to the Mediterranean Sea, most of its transformation taking place in the Camarinal sill surroundings. A series of repeated transects carried out in the eastern and western sides of the Strait, provided a temporal analysis of the water masses evolution: the temporal variability manifests seasonality in the surface waters, while interannual signal is mainly detected in the deeper water masses. It is worth remarking the statistically significant positive trend of Western Mediterranean Deep Water (0.009 °C/year) and Winter Intermediate Water (0.03 °C/year), with the latter showing also intermittent occurrence in the Strait.

  2. A comparison of coincident GRACE and ICESat data over Antarctica

    NARCIS (Netherlands)

    Gunter, B.; Urban, T.; Riva, R.E.M.; Helsen, M.M.; Harpold, R.; Poole, S.; Nagel, P.; Schutz, B.; Tapley, B.

    2009-01-01

    In this study, we present a comparison of coincident GRACE and ICESat data over Antarctica. The analysis focused on the secular changes over a 4-year period spanning from 2003 to 2007, using the recently reprocessed and publicly available data sets for both missions. The results show that the two in

  3. P-band radar ice sounding in Antarctica

    DEFF Research Database (Denmark)

    Dall, Jørgen; Kusk, Anders; Kristensen, Steen Savstrup

    2012-01-01

    In February 2011, the Polarimetric Airborne Radar Ice Sounder (POLARIS) was flown in Antarctica in order to assess the feasibility of a potential space-based radar ice sounding mission. The campaign has demonstrated that the basal return is detectable in areas with up to 3 km thick cold ice...

  4. DOMECair: An Airborne Campaign in Antarctica Supporting SMOS Calibration

    DEFF Research Database (Denmark)

    Skou, Niels; Kristensen, Steen Savstrup; Søbjærg, Sten Schmidl

    2013-01-01

    In search for a stable, well characterized terrestrial calibration target for SMOS, an airborne campaign was carried out in January 2013 over the Dome C area of Antarctica, and the surface was measured by an L-band radiometer. The focus was on homogeneity, and an area of 350 × 350 km around...

  5. Radiocarbon analyses along the EDML ice core in Antarctica

    NARCIS (Netherlands)

    van de Wal, R.S.W.; Meijer, H.A.J.; van Rooij, M.; van der Veen, C.

    2007-01-01

    Samples, 17 in total, from the EDML core drilled at Kohnen station Antarctica are analysed for 14CO and 14CO2 with a dry-extraction technique in combination with accelerator mass spectrometry. Results of the in situ produced 14CO fraction show a very low concentration of in situ produced 14CO. Despi

  6. Radiocarbon analyses along the EDML ice core in Antarctica

    NARCIS (Netherlands)

    Van de Wal, R. S. W.; Meijer, H. A. J.; De Rooij, M.; Van der Veen, C.

    2007-01-01

    Samples, 17 in total, from the EDML core drilled at Kohnen station Antarctica are analysed for (CO)-C-14 and (CO2)-C-14 with a dry-extraction technique in combination with accelerator mass spectrometry. Results of the in situ produced (CO)-C-14 fraction show a very low concentration of in situ produ

  7. The Twelfth Indian Scientific Expedition to Antarctica: Events and achievements

    Digital Repository Service at National Institute of Oceanography (India)

    Dhargalkar, V

    Delhi and Dr. B.N. Desai, Director, National Institute of Oceanography, Goa, families of the expedition members and friends. This was the smallest team M.V. Thuleland ever carried to Antarctica. On very next day of sailing the members were briefed about...

  8. Abrupt climate warming in East Antarctica during the early Holocene

    NARCIS (Netherlands)

    Cremer, H.; Heiri, O.; Wagner, B.; Wagner-Cremer, F.

    2007-01-01

    We report a centennial-scale warming event between 8600 and 8400 cal BP from Amery Oasis, East Antarctica, that is documented by the geochemical record in a lacustrine sediment sequence. The organic carbon content, the C/S ratio, and the sedimentation rate in this core have distinctly elevated value

  9. An evolutionary insight into Newcastle disease viruses isolated in Antarctica.

    Science.gov (United States)

    Soñora, Martin; Moreno, Pilar; Echeverría, Natalia; Fischer, Sabrina; Comas, Victoria; Fajardo, Alvaro; Cristina, Juan

    2015-08-01

    The disease caused by Newcastle disease virus (NDV) is a severe threat to the poultry industry worldwide. Recently, NDV has been isolated in the Antarctic region. Detailed studies on the mode of evolution of NDV strains isolated worldwide are relevant for our understanding of the evolutionary history of NDV. For this reason, we have performed Bayesian coalescent analysis of NDV strains isolated in Antarctica to study evolutionary rates, population dynamics, and patterns of evolution. Analysis of F protein cleavage-site sequences of NDV isolates from Antarctica suggested that these strains are lentogenic. Strains isolated in Antarctica and genotype I reference strain Ulster/67 diverged from ancestors that existed around 1958. The time of the most recent common ancestor (MRCA) was established to be around 1883 for all class II viruses. A mean rate of evolution of 1.78 × 10(-3) substitutions per site per year (s/s/y) was obtained for the F gene sequences of NDV strains examined in this study. A Bayesian skyline plot indicated a decline in NDV population size in the last 25 years. The results are discussed in terms of the possible role of Antarctica in emerging or re-emerging viruses and the evolution of NDV populations worldwide.

  10. Ross Ice Shelf and the Queen Maude Mounains, Antarctica

    Science.gov (United States)

    1991-01-01

    Part of the Ross Ice Shelf and the Queen Maude Mounains of Antarctica (55.5N, 178.0W) are in the background of this scene, oriented toward the south. Low stratocumulus clouds are predominant throughout most of the scene.

  11. Origin(s) of Antarctica's Wilkes subglacial basin

    NARCIS (Netherlands)

    Weihaupt, J.G.; Van der Hoeven, F.G.; Lorius, C.; Chambers, F.B.

    2013-01-01

    The Wilkes Subglacial Basin (WSB), the largest subglacial basin in East Antarctica, is a topographic depression of continental proportions that lies beneath the East Antarctic continental ice sheet. Discovered by the US Victoria Land Traverse 1959–60, the origin of the WSB and the influence of palae

  12. Surface and snowdrift sublimation at Princess Elisabeth station, East Antarctica

    NARCIS (Netherlands)

    Thiery, W.; Gorodetskaya, I.V.; Bintanja, R.; van Lipzig, N.P.M.; van den Broeke, M.R.; Reijmer, C.H.; Kuipers Munneke, P.

    2012-01-01

    In the near-coastal regions of Antarctica, a significant fraction of the snow precipitating onto the surface is removed again through sublimation – either directly from the surface or from drifting snow particles. Meteorological observations from an Automatic Weather Station (AWS) near the Belgian r

  13. Antarctica: Arena for South American Cooperation or Conflict.

    Science.gov (United States)

    Child, Jack

    A number of converging circumstances suggest that Antarctica may be a major object of geopolitical attention in South America in the decade to come. The Malvinas/Falklands crisis focused geopolitical attention on the South Atlantic and the chain of Southern (Austral) Islands which link the southern tip of South America to the Antarctic Peninsula.…

  14. Triassic leech cocoon from Antarctica contains fossil bell animal

    DEFF Research Database (Denmark)

    Bomfleur, Benjamin; Kerp, Hans; Taylor, Thomas N.

    2012-01-01

    , exceptional fossil deposits that preserve soft-bodied organisms provide a rare glimpse of the true biodiversity during past periods of Earth history. We here present an extraordinary find of a fossil ciliate that is encased inside the wall layer of a more than 200 Ma leech cocoon from Antarctica...

  15. Mass Casualty Incident Response and Aeromedical Evacuation in Antarctica

    Directory of Open Access Journals (Sweden)

    Mills, Christopher N

    2011-02-01

    Full Text Available Antarctica is one of the most remote regions on Earth. Mass casualty incident (MCI responses in Antarctica are prone to complications from multiple environmental and operational challenges. This review of the current status of MCI risks and response strategies for Antarctica focuses on aeromedical evacuation, a critical component of many possible MCI scenarios. Extreme cold and weather, a lack of medical resources and a multitude of disparate international bases all exert unique demands on MCI response planning. Increasing cruise ship traffic is also escalating the risk of MCI occurrence. To be successful, MCI response must be well coordinated and undertaken by trained rescuers, especially in the setting of Antarctica. Helicopter rescue or aeromedical evacuation of victims to off-continent facilities may be necessary. Currently, military forces have the greatest capacity for mass air evacuation. Specific risks that are likely to occur include structure collapses, vehicle incapacitations, vehicle crashes and fires. All of these events pose concomitant risks of hypothermia among both victims and rescuers. Antarctica’s unique environment requires flexible yet robust MCI response planning among the many entities in operation on the continent. [West J Emerg Med. 2011;12(1:37-42.

  16. Microbial Energetics Beneath the Taylor Glacier, Antarctica

    Science.gov (United States)

    Mikucki, J. A.; Turchyn, A. V.; Farquhar, J.; Priscu, J. C.; Schrag, D. P.; Pearson, A.

    2007-12-01

    Subglacial microbiology is controlled by glacier hydrology, bedrock lithology, and the preglacial ecosystem. These factors can all affect metabolic function by influencing electron acceptor and donor availability in the subglacial setting leaving biogeochemical signatures that can be used to determine ecosystem processes. Blood Falls, an iron-rich, episodic subglacial outflow from the Taylor Glacier in the McMurdo Dry Valleys Antarctica provides an example of how microbial community structure and function can provide insight into subglacial hydrology. This subglacial outflow contains cryoconcentrated, Pliocene-age seawater salts that pooled in the upper Taylor Valley and was subsequently covered by the advance of the Taylor Glacier. Biogeochemical measurements, culture-based techniques, and genomic analysis were used to characterize microbes and chemistry associated with the subglacial outflow. The isotopic composition of important geochemical substrates (i.e., δ34Ssulfate, Δ33Ssulfate, δ18Osulfate, δ18Owater, Δ14SDIC) were also measured to provide more detail on subglacial microbial energetics. Typically, subglacial systems, when driven to anoxia by the hydrolysis of organic matter, will follow a continuum of redox chemistries utilizing electron acceptors with decreasing reduction potential (e.g., Fe (III), sulfate, CO2). Our data provide no evidence for sulfate reduction below the Taylor Glacier despite high dissolved organic carbon (450 μM C) and measurable metabolic activity. We contend that, in the case of the Taylor Glacier, the in situ bioenergetic reduction potential has been 'short-circuited' at Fe(III)-reduction and excludes sulfate reduction and methanogenesis. Given the length of time that this marine system has been isolated from phototrophic production (~2 Mya) the ability to degrade and consume increasingly recalcitrant organic carbon is likely an important component to the observed redox chemistry. Our work indicates that glacier hydrology

  17. Seismic Constraints on the Mantle Viscosity Structure beneath Antarctica

    Science.gov (United States)

    Wiens, Douglas; Heeszel, David; Aster, Richard; Nyblade, Andrew; Wilson, Terry

    2015-04-01

    Lateral variations in upper mantle viscosity structure can have first order effects on glacial isostatic adjustment. These variations are expected to be particularly large for the Antarctic continent because of the stark geological contrast between ancient cratonic and recent tectonically active terrains in East and West Antarctica, respectively. A large misfit between observed and predicted GPS rates for West Antarctica probably results in part from the use of a laterally uniform viscosity structure. Although not linked by a simple relationship, mantle seismic velocities can provide important constraints on mantle viscosity structure, as they are both largely controlled by temperature and water content. Recent higher resolution seismic models for the Antarctic mantle, derived from data acquired by new seismic stations deployed in the AGAP/GAMSEIS and ANET/POLENET projects, offer the opportunity to use the seismic velocity structure to place new constraints on the viscosity of the Antarctic upper mantle. We use an Antarctic shear wave velocity model derived from array analysis of Rayleigh wave phase velocities [Heeszel et al, in prep] and examine a variety of methodologies for relating seismic, thermal and rheological parameters to compute a suite of viscosity models for the Antarctic mantle. A wide variety of viscosity structures can be derived using various assumptions, but they share several robust common elements. There is a viscosity contrast of at least two orders of magnitude between East and West Antarctica at depths of 80-250 km, reflecting the boundary between cold cratonic lithosphere in East Antarctica and warm upper mantle in West Antarctica. The region beneath the Ellsworth-Whitmore Mtns and extending to the Pensacola Mtns. shows intermediate viscosity between the extremes of East and West Antarctica. There are also significant variations between different parts of West Antarctica, with the lowest viscosity occurring beneath the Marie Byrd Land (MBL

  18. Sediment quality in depositional areas of Shelikof Strait and outermost Cook Inlet, July 1997 - July 1998 (NCEI Accession 0000702)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Minerals Management Service (MMS) program "Sediment Quality in Depositional Areas of Shelikof Strait and Outermost Cook Inlet," consisted of a two-year study...

  19. Optimal estimation of absolute geostrophic velocity field in vicinity of the Luzon Strait using variational data assimilation technique

    Institute of Scientific and Technical Information of China (English)

    兰健; 王东晓

    2002-01-01

    A P - vector method is opt'inized using the variational data assimilation technique (VDAT). The absolute geostrophic velocity fields in the vicinity of the Luzon Strait (LS) are calculated, the spatial structures and seasonal variations o{ the absolute geostrophic velocity field are investigated. Our results show that the Kuroshio enters the South China Sea (SCS) in the south and middle of the Luzon Strait and flows out in the north, so the Kuroshio makes a slight clockwise curve in the Luzon Strait, and the curve is strong in winter and weak in summer. During the winter, a westward current appears in the surface, and locates at the west of the Luzon Strait. It is the north part of a cyclonic gyre which exits in the northeast of the SCS; an anti-cyclonic gyre occurs on the intermediate level, and it exits in the northeast of the SCS, and an eastward current exits in the southeast of the anti-cyclonic gyre.

  20. Derelict Gear - Impacts of derelict fishing gear on marine fauna in Puget Sound and the Northwest Straits

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Puget Sound and the Northwest Straits have experienced a long history of commercial fishing activity. Although much of this fishing activity no longer takes place,...

  1. Volume transport data from a submarine cable in the Florida Strait from 1982 to 1998 (NODC Accession 0087879)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Daily mean volume transport data of the Florida Current collected with a submarine cable spanning from South Florida to the Grand Bahama Island in the Florida Strait...

  2. Taxonomy and distribution of benthic foraminifera from the sediments of Palk Strait, Tamil Nadu, east coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Gandhi, S.; Rajamanickam, G.V.; Nigam, R.

    A systematic study of benthic foraminifera has been made on 42 sediment samples collected between Mandapam and Kodiyakkarai, off Palk Strait, Tamil Nadu, India. A total of 102 benthic foraminiferal species belonging to 52 genera, 38 families, 23...

  3. Anthropogenic and natural CO2 exchange through the Strait of Gibraltar

    Directory of Open Access Journals (Sweden)

    J. Ruíz

    2009-04-01

    Full Text Available The exchange of both anthropogenic and natural inorganic carbon between the Atlantic Ocean and the Mediterranean Sea through Strait of Gibraltar was studied for a period of two years under the frame of the CARBOOCEAN project. A comprehensive sampling program was conducted, which was design to collect samples at eight fixed stations located in the Strait in successive cruises periodically distributed through the year in order to ensure a good spatial and temporal coverage. As a result of this monitoring, a time series namely GIFT (GIbraltar Fixed Time series has been established, allowing the generation of an extensive data set of the carbon system parameters in the area. Data acquired during the development of nine campaigns were analyzed in this work. Total inorganic carbon concentration (CT was calculated from alkalinity-pHT pairs and appropriate thermodynamic relationships, with the concentration of anthropogenic carbon (CANT being also computed using two methods, the ΔC* and the TrOCA approach. Applying a two-layer model of water mass exchange through the Strait and using a value of −0.85 Sv for the average transport of the outflowing Mediterranean water recorded in situ during the considered period, a net export of inorganic carbon from the Mediterranean Sea to the Atlantic was obtained, which amounted to 25±0.6 Tg C yr−1. A net alkalinity output of 16±0.6 Tg C yr−1 was also observed to occur through the Strait. In contrast, the Atlantic water was found to contain a higher concentration of anthropogenic carbon than the Mediterranean water, resulting in a net flux of CANT towards the Mediterranean basin of 4.20±0.04 Tg C yr−1 by using the ΔC* method, which constituted the most adequate approach for this environment. A carbon balance in the Mediterranean was assessed and fluxes through the Strait are discussed in relation to the highly diverse estimates available in the literature for the area and the different approaches

  4. An overview of the theta - S correlations in Fram Strait based on the MIZEX 84 data

    Directory of Open Access Journals (Sweden)

    Pawel Schlichtholz

    2002-06-01

    Full Text Available The water masses in Fram Strait have been analyzed on the basis of hydrographic casts taken in summer 1984 during the MIZEX 84 experiment. In particular, theta-S diagrams for 16 areas, each 5o in longitude and 1o in latitude, covering the strait from 77oN to 81oN are used to characterize the water masses and discuss their possible origin. Near the surface, the East Greenland Polar Front clearly separates the lighter, cold and fresh Polar Water (PW from the heavier, warm and saline Atlantic Water (AW. In the upper ocean, the data show a large spreading of the temperature maximum in the theta-S space associated with different modes of the AW recirculating southward below the PW. Two geographically distinct salinity minima are found in the intermediate layer below the AW. The denser one, in the Boreas Basin, is a feature typical of the Arctic Intermediate Water (AIW formed by winter convection to the south of the strait, while the lighter one is sandwiched in the Arctic Ocean outflow between the AW layer and the Upper Polar Deep Water (UPDW characterized by a downward salinity increase. In the deep layer, two salinity maxima are present. The shallower (and warmer one, associated with the Canadian Basin Deep Water (CBDW, appears all along the East Greenland Slope. A similar but weaker maximum is also found in the southeastern part of the strait. This maximum is perhaps a remnant of the maximum in the East Greenland Current after it has been recirculated back to the strait around the cyclonic gyres of the Nordic Seas. The deeper one appears typically as a near-bottom salinity jump characteristic of the Eurasian Basin Deep Water (EBDW. The jump is found in two distinct areas of the strait, to the north-west in the Lena Trough and to the south-east in the rift valley of the Knipovich Ridge. The maximum in the former area should have been advected from the Arctic Ocean below the CBDW, while the maximum in the latter area might have originated from

  5. Comparison of seasonal variability of Aquarius sea surface salinity time series with in situ observations in the Karimata Strait, Indonesia

    Science.gov (United States)

    Susanto, R. D.; Setiawan, A.; Zheng, Q.; Sulistyo, B.; Adi, T. R.; Agustiadi, T.; Trenggono, M.; Triyono, T.; Kuswardani, A.

    2016-12-01

    The seasonal variability of a full lifetime of Aquarius sea surface salinity time series from August 25, 2011 to June 7, 2015 is compared to salinity time series obtained from in situ observations in the Karimata Strait. The Karimata Strait plays dual roles in water exchange between the Pacific and the Indian Ocean. The salinity in the Karimata Strait is strongly affected by seasonal monsoon winds. During the boreal winter monsoon, northwesterly winds draws low salinity water from the South China Sea into the Java Sea and at the same time, the Java Sea receives an influx of the Indian Ocean water via the Sunda Strait. The Java Sea water will reduce the main Indonesian throughflow in the Makassar Strait. Conditions are reversed during the summer monsoon. Low salinity water from the South China Sea also controls the vertical structure of water properties in the upper layer of the Makassar Strait and the Lombok Strait. As a part of the South China Sea and Indonesian Seas Transport/Exchange (SITE) program, trawl resistance bottom mounted CTD was deployed in the Karimata Strait in mid-2010 to mid-2016 at water depth of 40 m. CTD casts during the mooring recoveries and deployments are used to compare the bottom salinity data. This in situ salinity time series is compared with various Aquarius NASA salinity products (the level 2, level 3 ascending and descending tracks and the seven-days rolling averaged) to check the consistency, correlation and statistical analysis. The preliminary results show that the seasonal variability of Aquarius salinity time series has larger amplitude variability compared to that of in situ data.

  6. Breakup of the Larsen Ice Shelf, Antarctica

    Science.gov (United States)

    2002-01-01

    Recent Moderate-resolution Imaging Spectroradiometer (MODIS) satellite imagery analyzed at the University of Colorado's National Snow and Ice Data Center revealed that the northern section of the Larsen B ice shelf, a large floating ice mass on the eastern side of the Antarctic Peninsula, has shattered and separated from the continent. This particular image was taken on March 5, 2002. The shattered ice formed a plume of thousands of icebergs adrift in the Weddell Sea. A total of about 3,250 square kilometers of shelf area disintegrated in a 35-day period beginning on January 31, 2002. Over the last five years, the shelf has lost a total of 5,700 square kilometers and is now about 40 percent the size of its previous minimum stable extent. Ice shelves are thick plates of ice, fed by glaciers, that float on the ocean around much of Antarctica. The Larsen B shelf was about 220 meters thick. Based on studies of ice flow and sediment thickness beneath the ice shelf, scientists believe that it existed for at least 400 years prior to this event and likely existed since the end of the last major glaciation 12,000 years ago. For reference, the area lost in this most recent event dwarfs Rhode Island (2,717 square kilometers) in size. In terms of volume, the amount of ice released in this short time is 720 billion tons--enough ice for about 12 trillion 10-kilogram bags. This is the largest single event in a series of retreats by ice shelves along the peninsula over the last 30 years. The retreats are attributed to a strong climate warming in the region. The rate of warming is approximately 0.5 degrees Celsius per decade, and the trend has been present since at least the late 1940s. Overall in the peninsula, the extent of seven ice shelves has declined by a total of about 13,500 square kilometers since 1974. This value excludes areas that would be expected to calve under stable conditions. Ted Scambos, a researcher with the National Snow and Ice Data Center (NSIDC) at

  7. Expressed sequence tag analysis of Antarctic hairgrass Deschampsia antarctica from King George Island, Antarctica.

    Science.gov (United States)

    Lee, Hyoungseok; Cho, Hyun Hee; Kim, Il-Chan; Yim, Joung Han; Lee, Hong Kum; Lee, Yoo Kyung

    2008-04-30

    Deschampsia antarctica is the only monocot that thrives in the tough conditions of the Antarctic region. It is an invaluable resource for the identification of genes associated with tolerance to various environmental pressures. In order to identify genes that are differentially regulated between greenhouse-grown and Antarctic field-grown plants, we initiated a detailed gene expression analysis. Antarctic plants were collected and greenhouse plants served as controls. Two different cDNA libraries were constructed with these plants. A total of 2,112 cDNA clones was sequenced and grouped into 1,199 unigene clusters consisting of 243 consensus and 956 singleton sequences. Using similarity searches against several public databases, we constructed a functional classification of the ESTs into categories such as genes related to responses to stimuli, as well as photosynthesis and metabolism. Real-time PCR analysis of various stress responsive genes revealed different patterns of regulation in the different environments, suggesting that these genes are involved in responses to specific environmental factors.

  8. Contrasting optical properties of surface waters across the Fram Strait and its potential biological implications

    DEFF Research Database (Denmark)

    Pavlov, Alexey K.; Granskog, Mats A.; Stedmon, Colin A.

    2015-01-01

    radiation (PAR, 400-700nm), but does result in notable differences in ultraviolet (UV) light penetration, with higher attenuation in the EGC. Future changes in the Arctic Ocean system will likely affect EGC through diminishing sea-ice cover and potentially increasing CDOM export due to increase in river......Underwater light regime is controlled by distribution and optical properties of colored dissolved organic matter (CDOM) and particulate matter. The Fram Strait is a region where two contrasting water masses are found. Polar water in the East Greenland Current (EGC) and Atlantic water in the West...... Spitsbergen Current (WSC) differ with regards to temperature, salinity and optical properties. We present data on absorption properties of CDOM and particles across the Fram Strait (along 79° N), comparing Polar and Atlantic surface waters in September 2009 and 2010. CDOM absorption of Polar water in the EGC...

  9. An operative lagrangian model for simulating radioactivity dispersion in the Strait of Gibraltar.

    Science.gov (United States)

    Periáñez, R

    2005-01-01

    GISPART (GIbraltar Strait PARticle Tracking model) is a three-dimensional particle tracking code to simulate the dispersion of radionuclides in the Strait of Gibraltar. It consists of a hydrodynamic module that is run off-line to determine tidal constants and residuals in the domain. This information is stored in several files that are read by the dispersion module to reconstruct water movements. The dispersion module uses a lagrangian approach. Thus, a radionuclide release is simulated by a number of particles, whose paths are computed individually. Radionuclide concentrations are obtained from the density of particles per water volume unit. Some examples of results are shown. The model is also available on-line.

  10. Spatial and temporal variations of Synechococcus and picoeukaryotes in the Taiwan Strait, China

    Institute of Scientific and Technical Information of China (English)

    HUANG Bangqin; LIN Xueju; HONG Huasheng

    2009-01-01

    The size-fractionated phytoplankton biomass, and the spatial and temporal variations in abundance of Synechococcus (SYN) and picoeukaryotes (PEUK) were measured in the Taiwan Strait during three cruises (August 1997, February-March 1998, and August 1998). The results show that picophytoplankton and nanophytoplankton dominate the phytoplankton biomass, in average of 38% and 40%, respectively. SYN and PEUK varied over time in abundance and carbon biomass, greater in summer than in winter, in range of (7.70-209.2)×106 and (0.75-15.4)×106 cells/cm2 in the abundance, and 1.93-52.3 and 1.57-32.4 mgC/cm2 in the carbon biomass, for SYN and PEUK, respectively. The horizontal distributions of both groups were diurnal but heterogeneous in abundance, depending on the groups and layer of depths. Temperature is the key controlling factor for picophytoplankton distribution (especially in winter) in the Strait.

  11. Effect of the Northern Sea Route Opening to the Shipping Activities at Malacca Straits

    Directory of Open Access Journals (Sweden)

    N.S.F. Abdul Rahman

    2014-12-01

    Full Text Available The opening of the Northern Sea Route as an alternative route for transporting cargoes between the Far East and Europe seems highly acceptable by shipping companies due to the great saving in fuel consumption, bunker cost, operating cost, emissions and journey time. This situation will not only affect the maritime business activity in the Straits of Malacca but also, the Malaysian economy in different perspectives when the vessels sail via the Suez Canal and the Indian Ocean are expected to decrease. The objective of this study is to analyse the implication in the opening of the Northern Sea Route on Maritime Sector of the Malaysian economy by using PESTEL analysis. The main scope is focusing more on the Malacca Straits shipping activity by using a number of parameters that have been obtained from Port Klang and Port Klang Authority through a set of questionnaires and interview sessions with industrial experts.

  12. Weathering the empire: meteorological research in the early British Straits Settlements.

    Science.gov (United States)

    Williamson, Fiona

    2015-09-01

    This article explores meteorological interest and experimentation in the early history of the Straits Settlements. It centres on the establishment of an observatory in 1840s Singapore and examines the channels that linked the observatory to a global community of scientists, colonial officers and a reading public. It will argue that, although the value of overseas meteorological investigation was recognized by the British government, investment was piecemeal and progress in the field often relied on the commitment and enthusiasm of individuals. In the Straits Settlements, as elsewhere, these individuals were drawn from military or medical backgrounds, rather than trained as dedicated scientists. Despite this, meteorology was increasingly recognized as of fundamental importance to imperial interests. Thus this article connects meteorology with the history of science and empire more fully and examines how research undertaken in British dependencies is revealing of the operation of transnational networks in the exchange of scientific knowledge.

  13. Support to oil spill emergencies in the Bonifacio Strait, western Mediterranean

    Science.gov (United States)

    Cucco, A.; Ribotti, A.; Olita, A.; Fazioli, L.; Sorgente, B.; Sinerchia, M.; Satta, A.; Perilli, A.; Borghini, M.; Schroeder, K.; Sorgente, R.

    2012-07-01

    An innovative forecasting system of the coastal marine circulation has been implemented in the Bonifacio Strait area, between Corsica and Sardinia, using a numerical approach to facilitate the rapid planning and coordination of remedial actions for oil spill emergencies at sea by local authorities. Downscaling and nesting techniques from regional to coastal scale and a 3-D hydrodynamic numerical model, coupled with a wind wave model, are the core of the integrated Bonifacio Strait system. Such a system is capable of predicting operationally the dispersion of hydrocarbon spills in the area, both in forward and backward mode, through an easy-to-use graphical user interface. A set of applications are described and discussed including both operational applications aimed at providing rapid responses to local oil spill emergences and managing applications aimed at mitigating the risk of oil spill impacts on the coast.

  14. Prospect for Petroleum Industry Exchange & Cooperation Between Bath Sides of Taiwan Strait

    Institute of Scientific and Technical Information of China (English)

    Wu Xunyue; HUO Fu

    1996-01-01

    @@ With the First Conference of the Petroleum Science and Technology between both sides of the Taiwan Straits successfully held in Taiwan last year, the exchange and cooperation in the petroleum industry between both sides has made the first step forward. The Chinese nation is an outstanding nation. To gain a floor for China in the world,both sides of the Straits must, on the premise of mutual complement and mutual benefit, strengthen their mutual exchange and cooperation as well as the trade contacts so as to promote their common prosperity. This point was a common understanding in the discussion of Mr. Chang Tzu-yuan, Chairman of Chinese Petroleum Corporation (CPC) and China National Petroleum Corporation (CNPC).This belief is further strengthened, when Mr. Chang Tzuyuan came to the mainland as a return visit in midNovember 1995.

  15. Zooplankton distribution across Fram Strait in autumn: Are small copepods and protozooplankton important?

    Science.gov (United States)

    Svensen, Camilla; Seuthe, Lena; Vasilyeva, Yulia; Pasternak, Anna; Hansen, Edmond

    2011-12-01

    We investigated zooplankton distribution in September 2006/2007 at eight stations across Fram Strait in contrasting water masses ranging from cold Polar water to warm Atlantic water. Our main objectives were: (1) to describe the plankton community in the upper 200 m during autumn, and (2) to investigate the importance of small-sized copepods and protozooplankton in an arctic ecosystem when the majority of the large Calanus species had entered diapause. We sampled both with a WP-2 net and Go-Flo bottle and show that small copepods food. Heterotrophic protozooplankton, on the other hand, were most likely bottom-up regulated by the availability of phytoplankton food and conclude that there was a strong link between the zooplankton community and the microbial food web in Fram Strait.

  16. Recent transient tracer distributions in the Fram Strait: estimation of anthropogenic carbon content and transport

    Directory of Open Access Journals (Sweden)

    T. Stöven

    2015-09-01

    Full Text Available The storage of anthropogenic carbon in the ocean's interior is an important process which modulates the increasing carbon dioxide concentrations in the atmosphere. The polar regions are expected to be net sinks for anthropogenic carbon. Transport estimates of dissolved inorganic carbon and the anthropogenic offset can thus provide information about the magnitude of the corresponding storage processes. Here we present a transient tracer, dissolved inorganic carbon (DIC and total alkalinity (TA data set along 78°50′ N sampled in the Fram Strait in 2012. A theory on tracer relationships is introduced which allows for an application of the Inverse Gaussian – Transit Time Distribution (IG-TTD at high latitudes and the estimation of anthropogenic carbon concentrations. Current velocity measurements along the same section were used to estimate the net flux of DIC and anthropogenic carbon through the Fram Strait. The new theory explains the differences between the theoretical (IG-TTD based tracer age relationship and the specific tracer age relationship of the field data by saturation effects during water mass formation and/or the deliberate release experiment of SF6 in the Greenland Sea in 1996 rather than by different mixing or ventilation processes. Based on this assumption, a maximum SF6 excess of 0.5–0.8 fmol kg−1 was determined in the Fram Strait at intermediate depths (500–1600 m. The anthropogenic carbon concentrations are 50–55 μmol kg−1 in the Atlantic Water/Recirculating Atlantic Water, 40–45 μmol kg−1 in the Polar Surface Water/warm Polar Surface Water and between 10–35 μmol kg−1 in the deeper water layers, with lowest concentrations in the bottom layer. The net DIC and anthropogenic carbon fluxes through the Fram Strait indicate a balanced exchange between the Arctic Ocean and the North Atlantic, although with high uncertainties.

  17. The Application of Fucus vesiculosus as a Bioindicator of 60Co Concentrations in the Danish Straits

    DEFF Research Database (Denmark)

    Boelskifte, S.

    1985-01-01

    The occurrence of 60Co in the Danish Straits is investigated by applying the seaweed Fucus vesiculosus as a bioindicator. In order to describe different dispersion situations, three areas have been studied separately: the North Sea, where it is possible to measure 60Co from sources in France and...... of distance from Barsebäck. Problems of uncertainty related to differences in environmental parameters are discussed and new investigations to improve the use of Fucus as a bioindicator are suggested....

  18. Numerical simulation of marine currents in the Bunaken Strait, North Sulawesi, Indonesia

    Science.gov (United States)

    Rompas, P. T. D.; Manongko, J. D. I.

    2016-04-01

    This study intended for the generation of hydroelectric power at suitable area of the strait in order to provide electric current to a close environment. The project uses a three-dimensional model of taking flow into account the variation of hydrostatic pressure in the liquid vertical layers. We brought back to a two-dimensional calculation using the shallow water equations. The objectives of the study are getting simultaneous obtaining the velocities of currents by the component of velocities and distributions of the kinetic energy from the numerical results. The Bunaken strait is 5280 m width for an average depth of 130 m. Numerical calculation is simulated using horizontal meshes of 60 side meters. The numerical solutions obtained by using a time step of one second. It found that there was no great difference between 2D and 3D numerical simulations because the effect of flow velocity in the vertical direction is very small. The numerical results have shown that the average current velocities when low and high tide currents are 1.46 m/s and 0.85 m/s respectively. The kinetic energy ranged from 0.01 to 2.54 kW/m2 when low and high tide in the Bunaken strait area at discharge of 1 Sv, whereas at discharge 2 Sv, 0.11-17.40 kW/m2 and 0.11-2.77 kW/m2 (when low and high tide currents). These results can used in the design of turbines for power generation marine currents in the Bunaken strait at depths below 60 meters.

  19. Deep Mediterranean Water footprint measured in the Strait of Gibraltar during the last decade.

    Science.gov (United States)

    Naranjo Rosa, Cristina; García Lafuente, Jesús; Sammartino, Simone; Sánchez Garrido, José Carlos

    2016-04-01

    Deep Mediterranean Water is formed during winter in the Mediterranean Sea due to atmospheric cooling of salty Mediterranean waters. When it reaches the Strait of Gibraltar it finally flows westward into the Atlantic, from where it begins to descend the continental slope by gravity while it mixes with the overlying waters and becomes lighter. Far beyond the strait itself it maintains a recognizable signal and so affects the thermohaline circulation of the Atlantic Ocean. Thus, the Strait of Gibraltar is the perfect site to monitor the interannual changes occurring over the whole Mediterranean Sea just before Mediterranean Waters incorporate to the Atlantic circulation. From October 2004 until today the Temperature and Salinity of the Mediterranean outflow through the Strait of Gibraltar have been monitored, resulting in a long-term temporal series with more than 11 years of measurements. A Conductivity-Temperature sensor is placed around 12 meters above the seafloor in the Espartel Sill (35°56'N 5°45'W), the last constriction the Mediterranean deep water finds before leaving the Mediterranean, and is configured to take measurements every 30 minutes. The instrument has been collecting data almost continuously from 2004, except for a 2.5 month gap in 2009 and a 5 months gap during 2011. This record allows the study of the long-term trend and the interannual changes occurring over the whole Mediterranean during the last 11 years. First results show a mean temperature of the deep Mediterranean waters of 13.20±0.06 °C and a mean salinity of 38.39±0.02. It is noteworthy the cold signals registered in 2006 and 2013, which could be the result of the severe winters of 2005 and 2012 in Europe, and the positive trend in 2015 toward warmer values. No significant trends have been found for the whole period. On the other hand, the time series exhibits a noticeable interannual variability that merits a deeper analysis.

  20. 77 FR 55452 - Lynn Canal-Icy Strait Resource Advisory Committee

    Science.gov (United States)

    2012-09-10

    ...The Lynn Canal-Icy Strait Resource Advisory Committee (LC-IS RAC) will meet in Juneau, AK. The committee is authorized under the Secure Rural Schools and Community Self-Determination Act (Pub. L. 112- 141) (the Act) and operates in compliance with the Federal Advisory Committee Act. The purpose of the committee is to improve collaborative relationships and to provide advice and recommendations......

  1. Eddy formation and surface flow field in the Luzon Strait area during the summer of 2009

    Science.gov (United States)

    Liu, Ze; Hou, Yijun; Xie, Qiang

    2015-09-01

    The formation of mesoscale eddies and the structure of the surface flow field in the Luzon Strait area were examined using in-situ CTD data, Argo float data, and multi-satellite remote sensing data collected from May to August 2009. The results show that vigorous water exchange between Kuroshio water and South China Sea (SCS) water began to emerge over the 200 m water column throughout the strait. Based on an objective definition of surface currents, float A69 tracked an anti-cyclonic eddy southwest of Taiwan Island under a Lagrangian current measurement. The salinity inside the anti-cyclonic eddy was higher than in typical SCS water but lower than in Kuroshio mainstream water, indicating that this eddy was induced by Kuroshio frontal intrusion through the Luzon Strait and into the SCS. From hydrographic data, we propose that continuous horizontal diffusion with high-salinity characteristics in the subsurface layer could extend to 119°E or even further west. The high-temperature filament, large positive sea level anomaly and clockwise geostrophic current all confirmed the existence of this warm eddy in May and June. A strongly negative wind stress curl maintained the eddy until it died. The surface flow field during July and August was rather complicated. Float A83 described an east-west orientated shuttle run in the 20°N section that was not reported by previous studies. At the same time, float A80 indicated a Kuroshio bend into the north-central region of Luzon Strait but it did not cross 120.5°E. The water mass rejoining the Kuroshio mainstream from the southern tip of Taiwan Island was less saline, indicating an entrainment of water from SCS by the Kuroshio bend.

  2. Development of Seismic Demand for Chang-Bin Offshore Wind Farm in Taiwan Strait

    OpenAIRE

    Yu-Kai Wang; Juin-Fu Chai; Yu-Wen Chang; Ti-Ying Huang; Yu-Shu Kuo

    2016-01-01

    Taiwan is located on the Pacific seismic belt, and the soil conditions of Taiwan’s offshore wind farms are softer than those in Europe. To ensure safety and stability of the offshore wind turbine supporting structures, it is important to assess the offshore wind farms seismic forces reasonably. In this paper, the relevant seismic and geological data are obtained for Chang-Bin offshore wind farm in Taiwan Strait, the probabilistic seismic hazard analysis (PSHA) is carried out, and the first un...

  3. Recent transient tracer distributions in the Fram Strait: estimation of anthropogenic carbon content and transport

    Science.gov (United States)

    Stöven, T.; Tanhua, T.; Hoppema, M.; von Appen, W.-J.

    2015-09-01

    The storage of anthropogenic carbon in the ocean's interior is an important process which modulates the increasing carbon dioxide concentrations in the atmosphere. The polar regions are expected to be net sinks for anthropogenic carbon. Transport estimates of dissolved inorganic carbon and the anthropogenic offset can thus provide information about the magnitude of the corresponding storage processes. Here we present a transient tracer, dissolved inorganic carbon (DIC) and total alkalinity (TA) data set along 78°50' N sampled in the Fram Strait in 2012. A theory on tracer relationships is introduced which allows for an application of the Inverse Gaussian - Transit Time Distribution (IG-TTD) at high latitudes and the estimation of anthropogenic carbon concentrations. Current velocity measurements along the same section were used to estimate the net flux of DIC and anthropogenic carbon through the Fram Strait. The new theory explains the differences between the theoretical (IG-TTD based) tracer age relationship and the specific tracer age relationship of the field data by saturation effects during water mass formation and/or the deliberate release experiment of SF6 in the Greenland Sea in 1996 rather than by different mixing or ventilation processes. Based on this assumption, a maximum SF6 excess of 0.5-0.8 fmol kg-1 was determined in the Fram Strait at intermediate depths (500-1600 m). The anthropogenic carbon concentrations are 50-55 μmol kg-1 in the Atlantic Water/Recirculating Atlantic Water, 40-45 μmol kg-1 in the Polar Surface Water/warm Polar Surface Water and between 10-35 μmol kg-1 in the deeper water layers, with lowest concentrations in the bottom layer. The net DIC and anthropogenic carbon fluxes through the Fram Strait indicate a balanced exchange between the Arctic Ocean and the North Atlantic, although with high uncertainties.

  4. Using Metasynthesis to Develop Sensitising Concepts to Understand Torres Strait Islander Migration

    Directory of Open Access Journals (Sweden)

    Vinnitta Patricia Mosby

    2013-03-01

    Full Text Available Emerging research indicates that more and more Indigenous peoples will be forced to migrate due to climate change. Current responses focus on mitigation and adaptation strategies. One such group, Torres Strait Islander people are already moving for other reasons and existing vulnerabilities compound levels of disadvantage when moving. It will be important to understand Torres Strait Islander people’s experiences of contemporary movements in order to inform policy development and facilitate the process of migration and resettlement as movement increases. A synthesis of existing studies would allow the development of sensitising concepts that could inform future research in the Torres Strait Islander context. This article presents a metasynthesis of six qualitative studies of the experiences of different Indigenous and minority groups at various stages of migration, displacement and resettlement. Articles were selected on contemporary movements (2001-2011 and importantly the inclusion of first person voice. Reciprocal translation was used to synthesise common themes and a core construct. The overarching construct that became apparent from the metasynthesis was ‘continuity of being’ through staying connected to self, family and culture. Three themes emerged: ‘freedom to be’, ‘staying close’ and ‘forming anchor’. These were enacted through people valuing their personal, social, religious and political freedom and recognising the importance of maintaining or forming strong social and family networks. When researching the experiences of Torres Strait Islanders it will be necessary to focus on motivations for moving, and understand the processes for staying connected to kin and homeland in order to achieve the desired outcomes of successful resettlement under conditions of uncertainty.

  5. Riau vegetables for Singapore consumers: A collaborative knowledge transfer project across the Straits of Malacca

    OpenAIRE

    Menkhoff, Thomas; Loh, Patrick H. M.; Bin, Chua Sin; Evers, Hans-Dieter; Chay, Yue Wah

    2007-01-01

    The paper analyses a recent collaborative knowledge transfer project between the Republic of Singapore and the Republic of Indonesia across the Straits of Malacca. The initiative was aimed at supplying the city state at the southern tip of the Malay Peninsula with green vegetables from Riau, Indonesia, and to provide technical assistance to Riau farmers on protected cultivation and post-harvest technologies. We reconstruct the bilateral evolution of the vegetable project in the context of the...

  6. Observations on the Characteristics of the Exchange Flow in the Daranelles Strait

    Science.gov (United States)

    2012-11-09

    North Atlantic Treaty Organization (NATO) Under- sea Research Center ( NURC ) in collaboration with the Turkish Navy Office of Navigation, Hydrography...from the R/V Alliance (a NATO NURC research vessel) as a part of TSS08 ( NURC project) and “Exchange Processes in Ocean Straits” (EPOS, NRL project...research project “Exchange Processes in Ocean Straits (EPOS)” under Program Element 61153N. We would like to thank everyone from the NATO NURC and the

  7. Regional Stratification and Shear of the Various Streams Feeding the Philippine Straits - ESR Component

    Science.gov (United States)

    2016-06-13

    Regional Stratification and Shear of the Various Streams Feeding the Philippine Straits – ESR Component Amy Ffield Earth & Space Research , 290...N0001406C0578 http://www.esr.org LONG-TERM GOALS To determine the impact of the regional oceanographic and atmospheric mean and variable ...Surface Temperature: Analysis of the OI Infrared Satellite SST reveals that the SST in the Philippine Archipelago region has significant variability

  8. Options for managing the sustainable use of green turtles: Perceptions of Hammond Islanders in Torres Strait

    Directory of Open Access Journals (Sweden)

    Grayson Jillian

    2010-01-01

    Full Text Available One of the largest populations of green turtles (Chelonia mydas in the world spends at least part of its life cycle in the remote Torres Strait between Australia and Papua New Guinea. This population is subjected to traditional harvests from geographically dispersed communities including along the northern and eastern coasts of Australia, Indonesia and south-western Pacific nations. In Torres Strait, green turtle hunting is classed as a traditional fishery and is guaranteed by Australian legislation (Native Title Act 1993 and the Torres Strait Treaty between Australia and Papua New Guinea that aims to protect the traditional lifestyle of the region′s indigenous peoples. To investigate the Islanders′ thoughts and aspirations regarding marine turtle management, we interviewed hunters and Islander Elders from the Hammond Island community in the Kaurareg nation of Kaiwalagal. Although not the Traditional Owners of the Kaiwalagal sea country in which they live and hunt, Hammond Islanders wish to be involved in the management of resources on which they depend, including marine turtles. They considered community-based processes to be important, especially the application of (1 cultural norms to the development of tools to achieve compliance and enforcement within the community, and (2 consensus-based decision-making amongst hunters and elders within the community, with regard to the use of more formal rules. However, the need for co-operation with other communities and stakeholders across scales was also recognised, particularly with regard to enforcement. Our results suggest that co-management is likely to be a more appropriate approach for managing green turtles in Torres Strait than either community-based management or government-driven management.

  9. Enforcing Ship-Based Marine Pollution for Cleaner Sea in the Strait of Malacca

    Directory of Open Access Journals (Sweden)

    Sutarji Kasmin

    2010-01-01

    Full Text Available The Strait of Malacca is most susceptible to ship-based marine pollution such as oil and grease due to the heavy volume of shipping in the Strait. By nature, oil is toxic to marine life, especially the polycyclic aromatic hydrocarbons (PAHs, one of the main components in crude oil that is very difficult to clean up, and could remain for years in the sediment and marine environment. Marine species that are constantly exposed to PAHs can exhibit developmental problems and are more susceptible to diseases. The number of ships passing through the Strait in 2000 was 55,957 and increased to 62,621 ships 5 years later. In 2007, the traffic volume increased to 70,718 ships. During the five-year period from 2000 to 2005, there were 144 cases of oil spills into the sea. One hundred eight cases were due to illegal discharge of dirty oil. However, only 32 ships were charged and subsequently, 14 ships were found guilty. This paper analyses the challenges faced by the Malaysian maritime enforcement agencies in enforcing the Environmental Quality Act 1974 in the Strait of Malacca. Some of these challenges relate to the maritime enforcement agencies’ short-comings, nature of the Strait’s users and the legal processes to bring offenders to court. Based on the analyses, it was revealed that the responsible agencies are inadequately equipped and trained to deal with the illegal discharge of dirty oil into the sea. In order to overcome these weaknesses, several new initiatives are suggested.

  10. Population biology of coral trout species in eastern Torres Strait: Implications for fishery management

    Science.gov (United States)

    Williams, Ashley J.; Currey, Leanne M.; Begg, Gavin A.; Murchie, Cameron D.; Ballagh, Aaron C.

    2008-09-01

    Coral trout ( Plectropomus spp.) are the main target species for commercial fishers in the eastern Torres Strait Reef Line Fishery (ETS RLF). The four species of coral trout known to occur in Torres Strait: Plectropomus leopardus, Plectropomus maculatus, Plectropomus areolatus and Plectropomus laevis are currently managed as a single species in Torres Strait, as there is no species-specific biological information available for the region which could be used to assess whether species differ in their response to fishing pressure. The aim of our study was to determine whether it is appropriate (biologically) to manage coral trout in the ETS RLF as a single species group or whether different management arrangements are required for some species. We used catch data and biological data from samples collected by commercial fishers to examine the distribution within Torres Strait and estimate a range of biological parameters for P. leopardus, P. maculatus and P. areolatus. Insufficient P. laevis samples were collected to reliably examine this species. Results indicated that the population biology, particularly the reproductive biology, of P. areolatus was substantially different to both P. leopardus and P. maculatus. Although it is difficult to predict the response to fishing, P. areolatus may be more vulnerable to fishing than P. leopardus and P. maculatus, due to the larger size at sex change observed for this species and the very low proportion of males protected by the current minimum size limit. Therefore, while the common management arrangements for P. leopardus and P. maculatus appear to be adequate for these species, separate management arrangements are needed for the sustainable harvest of P. areolatus populations in the ETS. Specifically, we recommend the introduction of a maximum size limit for P. areolatus, in addition to the current minimum size limit, which may allow a proportion of males some protection from fishing.

  11. "Dancing with the stars" - astronomy and music in the Torres Strait

    CERN Document Server

    Hamacher, Duane W

    2016-01-01

    Song and dance are a traditional means of strengthening culture and passing knowledge to successive generations in the Torres Strait of northeastern Australia. Dances incorporate a range of apparatuses to enhance the performance, such as dance machines (Zamiyakal) and headdresses (Dhari). The dances, songs, headdresses and dance machines work together to transfer important knowledge about subsistence survival, social structure, and cultural continuity. This paper explores how celestial phenomena inspire and inform music and dance.

  12. Port and Waterway Safety Assessment: Haro Strait/Boundary Pass USA - Canada Workshop Report

    Science.gov (United States)

    2002-02-26

    Strait. Small vessel operator certifications are highly regulated by Transport Canada. USA tug operators are certified. Crew is STCW certificated...Deep-sea fleet is regulated by PSC. For Alaskan fishing vessels, 90% have STCW certificates on vessels of 200 gross tons and larger. All...Canadian tugboat deck officers are certified in accordance with STCW . In some cases, there are two pilots on 40,000 DWT tankers when transiting (Canada

  13. First time-series optical photometry from Antarctica

    CERN Document Server

    Strassmeier, K G; Granzer, T; Tosti, G; DiVarano, I; Savanov, I; Bagaglia, M; Castellini, S; Mancini, A; Nucciarelli, G; Straniero, O; Distefano, E; Messina, S; Cutispoto, G

    2008-01-01

    Beating the Earth's day-night cycle is mandatory for long and continuous time-series photometry and had been achieved with either large ground-based networks of observatories at different geographic longitudes or when conducted from space. A third possibility is offered by a polar location with astronomically-qualified site characteristics. Aims. In this paper, we present the first scientific stellar time-series optical photometry from Dome C in Antarctica and analyze approximately 13,000 CCD frames taken in July 2007. We conclude that high-precision CCD photometry with exceptional time coverage and cadence can be obtained at Dome C in Antarctica and be successfully used for time-series astrophysics.

  14. Synchronous climate changes in Antarctica and the North Atlantic

    Science.gov (United States)

    Steig, E.J.; Brook, E.J.; White, J.W.C.; Sucher, C.M.; Bender, M.L.; Lehman, S.J.; Morse, D.L.; Waddington, E.D.; Clow, G.D.

    1998-01-01

    Central Greenland ice cores provide evidence of abrupt changes in climate over the past 100,000 years. Many of these changes have also been identified in sedimentary and geochemical signatures in deep-sea sediment cores from the North Atlantic, confirming the link between millennial-scale climate variability and ocean thermohaline circulation. It is shown here that two of the most prominent North Atlantic events - the rapid warming that makes the end of the last glacial period and the Bolling/Allerod-Younger Dryas oscillation - are also recorded in an ice core from Taylor Dome, in the western Ross Sea sector of Antarctica. This result contrasts with evidence from ice cores in other regions of Antarctica, which show an asynchronous response between the Northern and Southern Hemispheres.

  15. The establishment of GPS network in Grove Mountains, East Antarctica

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The Grove Mountains are located in Princess Elizabeth Land, East Antarctica, extending from 72° to 73°S latitude and 73° to 76°E longitude, covering approximately 8000 km2 areas. During the 2002/2003 austral summer season, the 19th CHINARE (Chinese National Antarctic Research Expedition) carried out the third expedition in Grove Mountains, East Antarctica. The Geodetic network was established, which can provide ground control for the satellite image map for the multi-discipline expedition in the Grove Mountains where seven permanent GPS benchmarks were set up supported by the helicopter and snow vehicles. All GPS sites besides Z001 were observed at least for one hour using the dual frequencies Trimble 4000ssi GPS receivers. The data were processed by the comprehensive GPS analysis package-GAMIT/GLOBK and the precision is good enough to satisfy with the acquirement of satellite mapping in this area.

  16. Optimal estimation of zonal velocity and transport through Luzon Strait using variational data assimilation technique

    Institute of Scientific and Technical Information of China (English)

    LAN Jian; BAO Xianwen; GAO Guoping

    2004-01-01

    A P-vector method was optimized using variational data assimilation technique, with which the vertical structures and seasonal variations of zonal velocities and transports were investigated. The results showed that westward and eastward flowes occur in the Luzon Strait in the same period in a year. However the net volume transport is westward. In the upper level (0m - -500m),the westward flow exits in the middle and south of the Luzon Strait, and the eastward flow exits in the north. There are two centers of westward flow and one center of eastward flow. In the middle of the Luzon Strait, westward and eastward flowes appear alternately in vertical direction. The westward flow strengthens in winter and weakens in summer. The net volume transport is strong in winter (5.53 Sv) but weak in summer (0.29 Sv). Except in summer, the volume transport in the upper level accounts for more than half of the total volume transport (0m - bottom). In summer, the net volume transport in the upper level is eastward (1.01 Sv), but westward underneath.

  17. Development of a Hydrodynamic Model of Puget Sound and Northwest Straits

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Zhaoqing; Khangaonkar, Tarang P.

    2007-12-10

    The hydrodynamic model used in this study is the Finite Volume Coastal Ocean Model (FVCOM) developed by the University of Massachusetts at Dartmouth. The unstructured grid and finite volume framework, as well as the capability of wetting/drying simulation and baroclinic simulation, makes FVCOM a good fit to the modeling needs for nearshore restoration in Puget Sound. The model domain covers the entire Puget Sound, Strait of Juan de Fuca, San Juan Passages, and Georgia Strait at the United States-Canada Border. The model is driven by tide, freshwater discharge, and surface wind. Preliminary model validation was conducted for tides at various locations in the straits and Puget Sound using National Oceanic and Atmospheric Administration (NOAA) tide data. The hydrodynamic model was successfully linked to the NOAA oil spill model General NOAA Operational Modeling Environment model (GNOME) to predict particle trajectories at various locations in Puget Sound. Model results demonstrated that the Puget Sound GNOME model is a useful tool to obtain first-hand information for emergency response such as oil spill and fish migration pathways.

  18. Domesticating Hybridity: Straits Chinese Cultural Heritage Projects in Malaysia and Singapore

    Directory of Open Access Journals (Sweden)

    Karen M. Teoh

    2015-12-01

    Full Text Available This article examines the literal and figurative domestication of Straits Chinese, or Peranakan, history in selected heritage projects in late twentieth-century Malaysia and Singapore. These projects simultaneously foreground Straits Chinese history as a symbol of interracial harmony and marginalize it as a cultural artifact. Over the late nineteenth and twentieth centuries, the ethnoculturally hybrid Straits Chinese positioned themselves as “the King’s Chinese,” champions of a Confucian-values renaissance, and citizens of independent Malaysia and Singapore. Their adaptability helped them survive the upheaval of imperialism, decolonization, and nation building, but it was also controversial for its suggestion of political flexibility. Today, Southeast Asian governments and the Peranakan themselves depict the community as a uniquely local model of ethnic integration. Museums and historic homes emphasize portrayals and consumption of supposedly feminine aspects of Peranakan culture (e.g., fashion and cuisine, while downplaying purportedly masculine elements (e.g., the possession of multiple nationalities. By conflating femininity, tradition, and racial hybridity, this approach reifies stereotypes about gender and cultural identity, and replaces transgressive potential with politically anodyne nostalgia and commercialization. As anxieties about race, national history, and belonging continue to undergird the modern polity, transnationalism and transculturalism are acceptable as long as they are confined to the past.

  19. Social Exclusion/Inclusion for Urban Aboriginal and Torres Strait Islander People

    Directory of Open Access Journals (Sweden)

    Maggie Walter

    2016-02-01

    Full Text Available Social exclusion social inclusion are useful concepts for making sense of the deeply embedded socio-economic disadvantaged position of Aboriginal and Torres Islander people in Australian. The concepts not only describe exclusion from social and economic participation; but seek to understand the dynamic processes behind their creation and reproduction. Yet few Australian studies go beyond describing Aboriginal over-representation on social exclusion indicators. Neither do they address the translatability of the concepts from non-Indigenous to Indigenous contexts despite mainstream studies finding the pattern of social exclusion (and therefore what social inclusion might look like differs for Aboriginal and Torres Strait Islander people to that of other disadvantaged groups. This paper uses data from the Longitudinal Study of Indigenous children to explore patterns of social exclusion across social, economic, well-being and community dimensions for urban Aboriginal and Torres Strait families. The paper then develops a contextual understanding of the processes and patterns that create and sustain social exclusion and the opportunities and challenges of moving to greater social inclusion for urban Aboriginal and Torres Strait Islander people/s.

  20. Potential polyunsaturated aldehydes in the Strait of Gibraltar under two tidal regimes.

    Science.gov (United States)

    Morillo-García, Soledad; Valcárcel-Pérez, Nerea; Cózar, Andrés; Ortega, María J; Macías, Diego; Ramírez-Romero, Eduardo; García, Carlos M; Echevarría, Fidel; Bartual, Ana

    2014-03-13

    Diatoms, a major component of the large-sized phytoplankton, are able to produce and release polyunsaturated aldehydes after cell disruption (potential PUAs or pPUA). These organisms are dominant in the large phytoplankton fraction (>10 µm) in the Strait of Gibraltar, the only connection between the Mediterranean Sea and the Atlantic Ocean. In this area, the hydrodynamics exerts a strong control on the composition and physiological state of the phytoplankton. This environment offers a great opportunity to analyze and compare the little known distribution of larger sized PUA producers in nature and, moreover, to study how environmental variables could affect the ranges and potential distribution of these compounds. Our results showed that, at both tidal regimes studied (Spring and Neap tides), diatoms in the Strait of Gibraltar are able to produce three aldehydes: Heptadienal, Octadienal and Decadienal, with a significant dominance of Decadienal production. The PUA released by mechanical cell disruption of large-sized collected cells (pPUA) ranged from 0.01 to 12.3 pmol from cells in 1 L, and from 0.1 to 9.8 fmol cell⁻¹. Tidal regime affected the abundance, distribution and the level of physiological stress of diatoms in the Strait. During Spring tides, diatoms were more abundant, usually grouped nearer the coastal basin and showed less physiological stress than during Neap tides. Our results suggest a significant general increase in the pPUA productivity with increasing physiological stress for the cell also significantly associated to low nitrate availability.

  1. Probabilistic Hazard of Tsunamis Generated by Submarine Landslides in the Cook Strait Canyon (New Zealand)

    Science.gov (United States)

    Lane, Emily M.; Mountjoy, Joshu J.; Power, William L.; Mueller, Christof

    2016-12-01

    Cook Strait Canyon is a submarine canyon that lies within ten kilometres of Wellington, the capital city of New Zealand. The canyon walls are covered with scars from previous landslides which could have caused local tsunamis. Palaeotsunami evidence also points to past tsunamis in the Wellington region. Furthermore, the canyon's location in Cook Strait means that there is inhabited land in the path of both forward- and backward-propagating waves. Tsunamis induced by these submarine landslides pose hazard to coastal communities and infrastructure but major events are very uncommon and the historical record is not extensive enough to quantify this hazard. The combination of infrequent but potentially very consequential events makes realistic assessment of the hazard challenging. However, information on both magnitude and frequency is very important for land use planning and civil defence purposes. We use a multidisciplinary approach bringing together geological information with modelling to construct a Probabilistic Tsunami Hazard Assessment of submarine landslide-generated tsunami. Although there are many simplifying assumptions used in this assessment, it suggests that the Cook Strait open coast is exposed to considerable hazard due to submarine landslide-generated tsunamis. We emphasise the uncertainties involved and present opportunities for future research.

  2. VLF wave injection experiments from Siple Station, Antarctica

    OpenAIRE

    R.A., Helliwell

    1987-01-01

    The background of VLF wave-particle experiments from Siple Station, Antarctica, including wave-induced precipitation is briefly reviewed. Single frequency ducted signals that exceed a certain 'threshold' intensity are observed at the conjugate point (Roberval, Quebec) to be amplified 30-50dB, with temporal growth rates of 30-200dB/s. Following saturation, variable frequency emissions are triggered. When a second signal is added to the first, with a frequency spacing Df

  3. The conquest of Antarctica; A la conquista de la Antartida

    Energy Technology Data Exchange (ETDEWEB)

    Tristan, R. M.

    2015-07-01

    The information obtained in the more than 15 projects designed for the XXVIII campaign to Antarctica, and in the they involved a total of 80 researchers, will serve to learn more about terrestrial magnetism, changes occurring in the climate, the behavior of the volcanoes, the evolution of the glaciers, the rate of thaw, the weather variations, characteristics of the lichens, the progress of pollution... Even know the past that remains frozen under the ice to predict what might happen in the future. (Author)

  4. Victoria Land, Ross Sea, and Ross Ice Shelf, Antarctica

    Science.gov (United States)

    2002-01-01

    On December 19, 2001, MODIS acquired data that produced this image of Antarctica's Victoria Land, Ross Ice Shelf, and the Ross Sea. The coastline that runs up and down along the left side of the image denotes where Victoria Land (left) meets the Ross Ice Shelf (right). The Ross Ice Shelf is the world's largest floating body of ice, approximately the same size as France. Credit: Jacques Descloitres, MODIS Land Rapid Response Team, NASA/GSFC

  5. Transiting planet candidates with ASTEP 400 at Dome C, Antarctica

    Science.gov (United States)

    Mékarnia, D.; Guillot, T.; Rivet, J.-P.; Schmider, F.-X.; Abe, L.; Gonçalves, I.; Agabi, A.; Crouzet, N.; Fruth, T.; Barbieri, M.; Bayliss, D. D. R.; Zhou, G.; Aristidi, E.; Szulagyi, J.; Daban, J.-B.; Fanteï-Caujolle, Y.; Gouvret, C.; Erikson, A.; Rauer, H.; Bouchy, F.; Gerakis, J.; Bouchez, G.

    2016-11-01

    ASTEP 400, the main instrument of the ASTEP (Antarctica Search for Transiting ExoPlanets) programme, is a 40 cm telescope, designed to withstand the harsh conditions in Antarctica, achieving a photometric accuracy of a fraction of millimagnitude on hourly time-scales for planet-hosting southern bright (R ˜ 12 mag) stars. We review the performances of this instrument, describe its operating conditions, and present results from the analysis of observations obtained during its first three years (2010-2012) of operation, before its repatriation in 2014. During this time, we observed a total of 22 stellar fields (1° × 1° field of view). Each field, in which we measured stars up to magnitude R = 18 mag, was observed continuously during ˜7 to ˜30 d. More than 200 000 frames were recorded and 310 000 stars processed, using an implementation of the optimal image subtraction photometry algorithm. We found 43 planetary transit candidates. 20 of these candidates were observed using spectroscopic follow-ups including four targets classified as good planet candidates. Our results demonstrate that accurate near-continuous photometric observations are achievable from the Concordia station at Dome C in Antarctica, even if we were not able to reach the nominal photometric precision of the instrument. We conducted a correlation analysis between the rms noise and a large number of external parameters and found that source of the ˜1 mmag correlated noise is not obvious and does not depend on a single parameter. However, our analysis provided some hints and guidance to increase the photometric accuracy of the instrument. These improvements should equip any future telescope operating in Antarctica.

  6. Tidal Energy Resource Assessment for McMurdo Station, Antarctica

    Science.gov (United States)

    2016-12-01

    unclear” (U.S. Antarctic Program Blue Ribbon Panel 2012). These studies have predominantly considered solar , wind, geother- mal, and waste wood and paper...tides are called spring tides (Figure 3). When the moon is at a right angle , perpen- dicular to the earth–sun connecting line, the lunar and solar ...capabilities at McMurdo Station, Antarctica, to reduce costs and emissions. Previous assessments considered wind, solar , and geothermal energy

  7. Direct gravimetric determination of aerosol mass concentration in central antarctica.

    Science.gov (United States)

    Annibaldi, Anna; Truzzi, Cristina; Illuminati, Silvia; Scarponi, Giuseppe

    2011-01-01

    In Antarctica, experimental difficulties due to extreme conditions have meant that aerosol mass has rarely been measured directly by gravimetry, and only in coastal areas where concentrations were in the range of 1-7 μg m(-3). The present work reports on a careful differential weighing methodology carried out for the first time on the plateau of central Antarctica (Dome C, East Antarctica). To solve problems of accurate aerosol mass measurements, a climatic room was used for conditioning and weighing filters. Measurements were carried out in long stages of several hours of readings with automatic recording of temperature/humidity and mass. This experimental scheme allowed us to sample from all the measurements (up to 2000) carried out before and after exposure, those which were recorded under the most stable humidity conditions and, even more importantly, as close to each other as possible. The automatic reading of the mass allowed us in any case to obtain hundreds of measurements from which to calculate average values with uncertainties sufficiently low to meet the requirements of the differential weighing procedure (±0.2 mg in filter weighing, between ±7% and ±16% both in aerosol mass and concentration measurements). The results show that the average summer aerosol mass concentration (aerodynamic size ≤10 μm) in central Antarctica is about 0.1 μg m(-3), i.e., about 1/10 of that of coastal Antarctic areas. The concentration increases by about 4-5 times at a site very close to the station.

  8. Ice crystal precipitation at Dome C site (East Antarctica)

    Science.gov (United States)

    Santachiara, G.; Belosi, F.; Prodi, F.

    2016-01-01

    For the first time, falling ice crystals were collected on glass slides covered with a thin layer of 2% formvar in chloroform at the Dome Concordia site (Dome C), Antarctica. Samplings were performed in the framework of the 27th Italian Antarctica expedition of the Italian National Program for Research in Antarctica in the period 21 February-6 August 2012. Events of clear-sky precipitations and precipitations from clouds were considered and the replicas obtained were examined under Scanning Electron Microscope (SEM). Several shapes of ice crystals were identified, including "diamond dust" (plates, pyramids, hollow and solid columns), and crystal aggregates varying in complexity. Single events often contained both small (10 μm to 50 μm) and large (hundreds of microns) crystals, suggesting that crystals can form simultaneously near the ground (height of a few hundred metres) and at higher layers (height of thousands of metres). Images of sampled crystal replicas showed that single bullets are not produced separately, but by the disintegration of combinations of bullets. Rimed ice crystals were absent in the Dome C samples, i.e. the only mode of crystal growth was water vapour diffusion. On considering the aerosol in the sampled crystals, we reached the conclusion that inertial impaction, interception and Brownian motion were insufficient to explain the scavenged aerosol. We therefore presume that phoretic forces play a role in scavenging during the crystal growth process.

  9. Antarctica's protected areas are inadequate, unrepresentative, and at risk.

    Science.gov (United States)

    Shaw, Justine D; Terauds, Aleks; Riddle, Martin J; Possingham, Hugh P; Chown, Steven L

    2014-06-01

    Antarctica is widely regarded as one of the planet's last true wildernesses, insulated from threat by its remoteness and declaration as a natural reserve dedicated to peace and science. However, rapidly growing human activity is accelerating threats to biodiversity. We determined how well the existing protected-area system represents terrestrial biodiversity and assessed the risk to protected areas from biological invasions, the region's most significant conservation threat. We found that Antarctica is one of the planet's least protected regions, with only 1.5% of its ice-free area formally designated as specially protected areas. Five of the distinct ice-free ecoregions have no specially designated areas for the protection of biodiversity. Every one of the 55 designated areas that protect Antarctica's biodiversity lies closer to sites of high human activity than expected by chance, and seven lie in high-risk areas for biological invasions. By any measure, including Aichi Target 11 under the Convention on Biological Diversity, Antarctic biodiversity is poorly protected by reserves, and those reserves are threatened.

  10. Antarctica's protected areas are inadequate, unrepresentative, and at risk.

    Directory of Open Access Journals (Sweden)

    Justine D Shaw

    2014-06-01

    Full Text Available Antarctica is widely regarded as one of the planet's last true wildernesses, insulated from threat by its remoteness and declaration as a natural reserve dedicated to peace and science. However, rapidly growing human activity is accelerating threats to biodiversity. We determined how well the existing protected-area system represents terrestrial biodiversity and assessed the risk to protected areas from biological invasions, the region's most significant conservation threat. We found that Antarctica is one of the planet's least protected regions, with only 1.5% of its ice-free area formally designated as specially protected areas. Five of the distinct ice-free ecoregions have no specially designated areas for the protection of biodiversity. Every one of the 55 designated areas that protect Antarctica's biodiversity lies closer to sites of high human activity than expected by chance, and seven lie in high-risk areas for biological invasions. By any measure, including Aichi Target 11 under the Convention on Biological Diversity, Antarctic biodiversity is poorly protected by reserves, and those reserves are threatened.

  11. Assessment of Radiation and Heavy Metals Risk due to the Dietary Intake of Marine Fishes (Rastrelliger kanagurta) from the Straits of Malacca

    National Research Council Canada - National Science Library

    Khandaker, M U; Asaduzzaman, Kh; Nawi, S M; Usman, A R; Amin, Y M; Daar, E; Bradley, D A; Ahmed, H; Okhunov, A A

    2015-01-01

    The environment of the Straits of Malacca receives pollution as a result of various industrial and anthropogenic sources, making systematic studies crucial in determining the prevailing water quality...

  12. Arctic Outflow West Of Greenland: Nine Years Of Volume And Freshwater Transports From Observations In Davis Strait

    Science.gov (United States)

    Curry, B.; Lee, C.; Petrie, B.; Moritz, R. E.; Kwok, R.

    2014-12-01

    Recent Arctic changes suggest alterations in the export of freshwater from the Arctic to the North Atlantic, with conceivable impacts on the Atlantic Meridional Overturning circulation. Approximately 50% of the Arctic outflow exits west of Greenland, traveling through the Canadian Arctic Archipelago (CAA) and into Baffin Bay before crossing Davis Strait. The CAA outflow contributes over 50% of the net southward freshwater outflow through Davis Strait. The remainder is deeper outflow from Baffin Bay, flow from the West Greenland Current and runoff from West Greenland and CAA glaciers. Since September 2004, an observational program in Davis Strait has quantified volume and freshwater transport variability. The year-round program includes velocity, temperature and salinity measurements from 15 moorings spanning the full width (330 km) of the strait accompanied by autonomous Seagliders surveys (average profile separation = 4 km) and autumn ship-based hydrographic sections. Over the shallow Baffin Island and West Greenland shelves, moored instrumentation provides temperature and salinity measurements near the ice-ocean interface. From 2004-2013, the average net volume and liquid freshwater transports are -1.6 ± 0.2 Sv, -94 ± 7 mSv, respectively (salinity referenced to 34.8 and negative indicates southward transport); sea ice contributes an additional -10 ± 1 mSv. Over this period, volume and liquid freshwater transports show significant interannual variability and no clear trends, but a comparison with reanalyzed 1987-90 data indicate a roughly 40% decrease in net southward liquid volume transport and a corresponding an almost 30% decrease in freshwater transport. Connections between the Arctic are also captured, e.g., a unique yearlong Davis Strait freshening event starting September 2009 that was likely driven by an earlier freshening (January 2009 - April/May 2010) in the Canadian Arctic. The Davis Strait autumn 2009 salinity minimum was fresher (by about 0

  13. Preliminary microphysical characterization of precipitation at ground over Antarctica coast

    Science.gov (United States)

    Roberto, Nicoletta; Adirosi, Elisa; Montopoli, Mario; Baldini, Luca; Dietrich, Stefano; Porcù, Federico

    2017-04-01

    The primary mass input of the Antarctic ice sheet is snow precipitation which is one of the most direct climatic indicators. Climatic model simulations of precipitations over Antarctica is an important task to assess the variation of ice sheet over long temporal scale. The main source of precipitation information in Antarctica regions derive from satellite observations. However, satellite measurements and products need to be calibrated and validated with observations from ground sensors. In spite of their key role, precipitation measurements at ground are scarce and not appropriate to provide the specific characteristic of precipitation particles that influence the scattering and absorption properties of ice particles. Recently, different stations in Antarctica (Princess Elizabeth, McMurdo, Mario Zucchelli) are equipping observatories for cloud and precipitation observations. The setup of the observatory at the Italian Station, Mario Zucchelli (MZ) plans to integrate the current instrumentation for weather measurements with other instruments specific for precipitation observations, in particular, a 24-GHz vertical pointing radar and a laser disdrometer Parsivel. The synergetic use of the set of instruments allows for characterizing precipitation and studying properties of Antarctic precipitation such as dimension, shapes, fall behavior, density of particles, particles size distribution, particles terminal velocity, reflectivity factor and including some information on their vertical extent. Last November, the OTT Parsivel disdrometer was installed on the roof of a logistic container (at 6 m of height) of the MZ station (Latitude 74° 41' 42" S; Longitude 164° 07' 23E") in the Terranova Bay. The disdrometer measures size and fall velocity of particles, passing through a laser matrix from which the Particle Size Distribution (PSD) is obtained. In addition, some products such as reflectivity factor, snow rate and snow accumulation can be inferred by properly

  14. STUDY OF CHLOROPHYLL-A DISTRIBUTIONS IN LOMBOK STRAIT USING BIOGEOCHEMICAL MODEL BASED ON REGIONAL OCEAN MODELLING SYSTEM (ROMS

    Directory of Open Access Journals (Sweden)

    KADEK ARY ANGGRAENI

    2015-06-01

    Full Text Available Regional Ocean Modelling System (ROMS has been intended to be a multi-purpose, multi-disciplinary oceanic modeling tool. The Biogeochemical model have coupled to ROMS consists of a system of seven coupled partial differential equations that include: nitrate, ammonium, small and large detritus, phytoplanJ..'ton, zooplankton, and a dynamic phytoplanJ..-ton carbon to chlorophyll ratio. The study of distribution patterns of chlorophyll-a in Lombok Strait (-7 °N - ·10 •sand 114 "E - 117 °E in 2006 was analyzed using the Biogeochemical model based on ROMS. The results show that low chlorophyll-a distributions (0.20 mgChl-a/m3 observed in Lombok Strait in ,January. Chlorophyll-a estimated around the southern part of Bali Strait and low chlorophyll-a distribution in upper layer of the Lomhok Strait. Chlorophyll-a of the booming (0.32 mgChl-a/m3 observed in August. The northeast current direction moves to the west and southern part of research area through Lombok Strait. The highest chlorophyll-a concentration estimated in the northern and southwestern part of Bali Tsland and also in the southern part of Lombok Island. During dry monsoon, southeasterly wind blow from Australia generates upwelling process (low temperature and nutrient-rich water near the surface also estimated from ROMS.

  15. Water exchange between Algeciras Bay and the Strait of Gibraltar: A study based on HF coastal radar

    Science.gov (United States)

    Chioua, J.; Dastis, C.; González, C. J.; Reyes, E.; Mañanes, R.; Ruiz, M. I.; Álvarez, E.; Yanguas, F.; Romero, J.; Álvarez, O.; Bruno, M.

    2017-09-01

    This study analyses the water mass exchanges at subinertial scale between Algeciras Bay and the adjacent Strait of Gibraltar. The mechanisms triggering this exchange process is investigated with the aid of recently-acquired data on surface currents obtained using a system of HF coastal radars deployed on the eastern side of the Strait, and remotely-sensed images of sea surface temperature (SST) and chlorophyll from the MODIS sensor of the Aqua satellite. HF radar data on surface currents are analyzed by the application of real empirical orthogonal function (EOF) decomposition, which produces three EOF modes explaining more than 70% of the variance of the surface currents at the mouth of the Bay (modes 2, 3, and 6). Mode 2 is related to the fluctuations of the Atlantic Jet in the central zone of the Strait, mainly due to a combined effect of the atmospheric pressure fluctuations in the Western Mediterranean Sea and local wind in the eastern side of the Strait; mode 3 is related to the coastal currents induced by zonal wind forcing on the north-western coast of the Strait and Alboran Sea; and mode 6 seems to be related to water transport induced by winds blowing with a significant north component into and out of the Bay.

  16. The Forest Pattern and Its Variation Characteristics in Economic Zone on the Western Coast of the Taiwan Straits

    Institute of Scientific and Technical Information of China (English)

    Juan; TAN; Qing; WANG; Min; WANG; Chenyan; SHA; Junjie; RUAN; Shenfa; HUANG

    2013-01-01

    Taking Economic Zone on the Western Coast of the Taiwan Straits as the study area,we use GIS,remote sensing,mathematical statistics and other methods,to analyze the forest pattern and its variation characteristics in Economic Zone on the Western Coast of the Taiwan Straits during the period 1992-2008;use canonical correspondence analysis(CCA)to examine the effects of environmental factors on changes in forest pattern.The results show that the forest resources are rich in Economic Zone on the Western Coast of the Taiwan Straits,accounting for 61.40% of the total area,but the geographical distribution is very uneven,with obvious regional and elevation gradient difference;since1992,the forest has been dwindling in Economic Zone on the Western Coast of the Taiwan Straits,from 89 300 km2 in 1992 to 88 300 km2 in 2008;in terms of changes in region and elevation gradient,there is obvious difference in the forest,and the central and western forest of Wuyi Mountain tends to decline obviously;the main environmental factors influencing changes in forest pattern in Economic Zone on the Western Coast of the Taiwan Straits include temperature,sunshine hours,GDP per capita and precipitation;evaporation,evaporation and population density have weak effects on changes in forest pattern.

  17. Observed Intraseasonal Oceanic Variations in the Eastern Equatorial Indian Ocean and in the Outflow Straits of the Indonesian Throughflow

    Directory of Open Access Journals (Sweden)

    Iskhaq Iskandar

    2010-09-01

    Full Text Available The observed currents in the eastern equatorial Indian Ocean and in the outflow straits of the Indonesian Throughflow (ITF are shown to have significant intraseasonal variations and coherency during January 2004 – November 2006. The wavelet analysis between the eastern equatorial Indian Ocean and the ITF straits demonstrates significant intraseasonal coherency for the observed current at 50m depth. At 150m depth, the intraseasonal coherency only occurs between the observed currents in the eastern equatorial Indian Ocean and in the Lombok and Ombai Straits. On the other hand, at 350m depth the intraseasonal coherency is only found between the eastern equatorial Indian Ocean and the Ombai Strait. This intraseasonal coherency is associated with the wind-forced equatorial Kelvin waves which propagate eastward along the equatorial and coastal wave guides. Near-surface intraseasonal variations are associated with the first baroclinic mode with typical phase speed of 2.91 ± 0.46 m s-1, while the deeper layer intraseasonal variations are associated with the second baroclinic mode with typical phase speed of 1.59 ± 0.18 m s-1. Moreover, the lag correlations between the zonal winds and the observed currents at the ITF straits further demonstrate the source of intraseasonal variations in the ITF.

  18. Influence of persistent wind scour on the surface mass balance of Antarctica

    NARCIS (Netherlands)

    Das, I.; Bell, R.E.; Lenaerts, J.T.M.; Broeke, M.R. van den

    2013-01-01

    Accurate quantification of surface snow accumulation over Antarctica is a key constraint for estimates of the Antarctic mass balance, as well as climatic interpretations of ice-core records1,2. Over Antarctica, near-surface winds accelerate down relatively steep surface slopes, eroding and sublimati

  19. Relative sea-level rise around East Antarctica during Oligocene glaciation

    NARCIS (Netherlands)

    Stocchi, P.; Escutia, C.; Houben, A.J.P.; Vermeersen, B.L.A.; Bijl, P.K.; Brinkhuis, H.; Deconto, R.M.; Galeotti, S.; Passchier, S.; Pollard, D.

    2013-01-01

    During the middle and late Eocene (∼ 48-34 Myr ago), the Earth's climate cooled and an ice sheet built up on Antarctica. The stepwise expansion of ice on Antarctica induced crustal deformation and gravitational perturbations around the continent. Close to the ice sheet, sea level rose despite an ove

  20. Relative sea-level rise around East Antarctica during Oligocene glaciation

    NARCIS (Netherlands)

    Stocchi, P.; Escutia, C.; Houben, A.J.P.; Vermeersen, B.L.A.; Bijl, P.K.; Brinkhuis, H.; DeConto , R.M.; Galeotti, S.; Passchier, S.; Pollard, D.; IODP Expedition 318 Scientists; Houben, A.J.P.

    2013-01-01

    During the middle and late Eocene (similar to 48-34 Myr ago), the Earth's climate cooled(1,2) and an ice sheet built up on Antarctica. The stepwise expansion of ice on Antarctica(3,4) induced crustal deformation and gravitational perturbations around the continent. Close to the ice sheet, sea level

  1. Relative sea-level rise around East Antarctica during Oligocene glaciation

    NARCIS (Netherlands)

    Stocchi, P.; Escutia, C.; Houben, A.J.P.; Vermeersen, B.L.A.; Bijl, P.K.; Brinkhuis, H.; Deconto, R.M.; Galeotti, S.; Passchier, S.; Pollard, D.

    2013-01-01

    During the middle and late Eocene (∼ 48-34 Myr ago), the Earth's climate cooled and an ice sheet built up on Antarctica. The stepwise expansion of ice on Antarctica induced crustal deformation and gravitational perturbations around the continent. Close to the ice sheet, sea level rose despite an ove

  2. Relative sea-level rise around East Antarctica during Oligocene glaciation

    NARCIS (Netherlands)

    Stocchi, P.; Escutia, C.; Houben, A.J.P.; Vermeersen, B.L.A.; Bijl, P.K.; Brinkhuis, H.; DeConto , R.M.; Galeotti, S.; Passchier, S.; Pollard, D.; IODP Expedition 318 Scientists; Houben, A.J.P.

    2013-01-01

    During the middle and late Eocene (similar to 48-34 Myr ago), the Earth's climate cooled(1,2) and an ice sheet built up on Antarctica. The stepwise expansion of ice on Antarctica(3,4) induced crustal deformation and gravitational perturbations around the continent. Close to the ice sheet, sea level

  3. Antibacterial, antifungal and antiprotozoal activities of fungal communities present in different substrates from Antarctica

    Science.gov (United States)

    Antarctica is a pristine and extreme environment that represents a unique opportunity for taxonomic, ecological and biotechnological studies of the microorganisms. In the present work, the fungal communities of rhizosphere soil of Deschampsia antarctica, soil, ornithogenic soil, marine and lake sedi...

  4. Antarctica: The Continuing Experiment. Foreign Policy Association Headline Series, No. 273.

    Science.gov (United States)

    Quigg, Philip W.

    One of a series of booklets on world issues examines the sharpened differences between those nations that have declared sovereignty over parts of Antarctica and those that have not; between those nations that have arbitrarily assumed responsibility for the administration of Antarctica and the smaller, more numerous nations that believe their…

  5. Influence of Persistent Wind Scour on the Surface Mass Balance of Antarctica

    Science.gov (United States)

    Das, Indrani; Bell, Robin E.; Scambos, Ted A.; Wolovick, Michael; Creyts, Timothy T.; Studinger, Michael; Fearson, Nicholas; Nicolas, Julien P.; Lenaerts, Jan T. M.; vandenBroeke, Michiel R.

    2013-01-01

    Accurate quantification of surface snow accumulation over Antarctica is a key constraint for estimates of the Antarctic mass balance, as well as climatic interpretations of ice-core records. Over Antarctica, near-surface winds accelerate down relatively steep surface slopes, eroding and sublimating the snow. This wind scour results in numerous localized regions (Antarctica. The scour zones are persistent because they are controlled by bedrock topography. On the basis of our Dome A observations, we develop an empirical model to predict wind-scour zones across the Antarctic continent and find that these zones are predominantly located in East Antarctica. We estimate that approx. 2.7-6.6% of the surface area of Antarctica has persistent negative net accumulation due to wind scour, which suggests that, across the continent, the snow mass input is overestimated by 11-36.5 Gt /yr in present surface-mass-balance calculations.

  6. U.S. Geological Survey Scientific Activities in the Exploration of Antarctica: Introduction to Antarctica (Including USGS Field Personnel: 1946-59)

    Science.gov (United States)

    Tony K. Meunier Edited by Williams, Richard S.; Ferrigno, Jane G.

    2007-01-01

    INTRODUCTION Antarctica is the planet's fifth largest continent [13.2 million km2 (5.1 million mi2)]; it contains the Earth's largest (of two) remaining ice sheets; it is considered to be one of the most important scientific laboratories on Earth. This report is the introduction to a series that covers 60 years of U.S. Geological Survey (USGS) scientific activity in Antarctica. It will concentrate primarily on three major topics:

  7. Special offer-7 days fly and drive Antarctica: The role of wilderness protection in deciding whether (semi) permanent tourist facilities in Antarctica should be prohibited

    Science.gov (United States)

    Kees Bastmeijer

    2007-01-01

    Antarctica is often described as one of the world’s last wildernesses. Since 1990, tourism to this wilderness is developing rapidly. In a period of 15 years, the number of tourists that make landings in Antarctica has increased from 2,500 (1990/91) to more than 23,000 (2004/05). The diversity of tourist activities is also increasing. The 1991 Protocol on Environmental...

  8. Liquid export of Arctic freshwater components through the Fram Strait 1998–2011

    Directory of Open Access Journals (Sweden)

    G. Kattner

    2013-01-01

    Full Text Available We estimated the magnitude and composition of southward liquid freshwater transports in the East Greenland Current near 79° N in the Western Fram Strait between 1998 and 2011. Previous studies have found this region to be an important pathway for liquid freshwater export from the Arctic Ocean to the Nordic Seas and the North Atlantic subpolar gyre. Our transport estimates are based on six hydrographic surveys between June and September and concurrent data from moored current meters. We combined concentrations of liquid freshwater, meteoric water (river water and precipitation, sea ice melt and brine from sea ice formation, and Pacific Water, presented in Dodd et al. (2012, with volume transport estimates from an inverse model. The average of the monthly snapshots of southward liquid freshwater transports between 10.6° W and 4° E is 100 ± 23 mSv (3160 ± 730 km3 yr−1, relative to a salinity of 34.9. This liquid freshwater transport consists of about 130% water from rivers and precipitation (meteoric water, 30% freshwater from the Pacific, and −60% (freshwater deficit due to a mixture of sea ice melt and brine from sea ice formation. Pacific Water transports showed the highest variation in time, effectively vanishing in some of the surveys. Comparison of our results to the literature indicates that this was due to atmospherically driven variability in the advection of Pacific Water along different pathways through the Arctic Ocean. Variations in most liquid freshwater component transports appear to have been most strongly influenced by changes in the advection of these water masses to the Fram Strait. However, the local dynamics represented by the volume transports influenced the liquid freshwater component transports in individual years, in particular those of sea ice melt and brine from sea ice formation. Our results show a similar ratio of the transports of meteoric water and net sea ice melt as previous studies. However, we observed a

  9. Reconstruction of the East Africa and Antarctica continental margins

    Science.gov (United States)

    Nguyen, Luan C.; Hall, Stuart A.; Bird, Dale E.; Ball, Philip J.

    2016-06-01

    The Early Jurassic separation of Antarctica from Africa plays an important role in our understanding of the dispersal of Gondwana and Pangea. Previous reconstruction models contain overlaps and gaps in the restored margins that reflect difficulties in accurately delineating the continent-ocean-boundary (COB) and determining the amount and distribution of extended continental crust. This study focuses on the evolution of the African margin adjacent to the Mozambique Basin and the conjugate Antarctic margin near the Riiser-Larsen Sea. Satellite-derived gravity data have been used to trace the orientations and landward limits of fracture zones. A 3-D gravity inversion has produced a crustal thickness model that reliably quantifies the extent and amount of stretched crust. Crustal thicknesses together with fracture zone terminations reveal COBs that are significantly closer to the African and Antarctic coasts than previously recognized. Correlation of fracture zone azimuths and identified COBs suggests Antarctica began drifting away from Africa at approximately 171 Ma in a roughly SSE direction. An areal-balancing method has been used to restore the crust to a uniform prerift thickness so as to perform a nonrigid reconstruction for both nonvolcanic and volcanic margins. Both margins reveal a trend of increasing extension from east to west. Our results suggest Africa underwent extension of 60-120 km, while Antarctic crust was stretched by 105-180 km. Various models tested to determine the direction of extension during rifting suggest that Antarctica moved away from Africa in a WNW-ESE direction during the period between 184 and 171 Ma prior to the onset of seafloor spreading.

  10. Seasonal features of black carbon measured at Syowa Station, Antarctica

    Science.gov (United States)

    Hara, K.; Osada, K.; Yabuki, M.; Shiobara, M.; Yamanouchi, T.

    2015-12-01

    Black carbon (BC) is one of important aerosol constituents because the strong light absorption ability. Low concentrations of aerosols and BC let BC make insignificant contribution to aerosol radiative forcing in the Antarctica at the moment. Because of less or negligible source strength of BC in the Antarctic circle, BC can be used as a tracer of transport from the mid-latitudes. This study aims to understand seasonal feature, transport pathway, and origins of black carbon in the Antarctic coats. Black carbon measurement has been made using 7-wavelength aethalometer at Syowa Station, Antarctica since February, 2005. Mass BC concentrations were estimated from light attenuation by Weingartner's correction procedure (Weingartner et al., 2003) in this study. Detection limit was 0.2 - 0.4 ng/m3 in our measurement conditions (2-hour resolution and flow rate of ca. 10LPM). BC concentrations ranged from near detection limit to 55.7 ng/m3 at Syowa Station, Antarctica during the measurements. No trend has been observed since February, 2005. High BC concentrations were coincident with poleward flow from the mid-latitudes under the storm conditions by cyclone approach, whereas low BC concentrations were found in transport from coastal regions and the Antarctic continent. Considering that outflow from South America and Southern Africa affect remarkably air quality in the Southern Ocean of Atlantic and Indian Ocean sectors, BC at Syowa Station might be originated from biomass burning and human activity on South America and Southern Africa. Seasonal features of BC at Syowa Station shows maximum in September - October and lower in December - April. Spring maximum in September - October was obtained at the other Antarctic stations (Neumayer, Halley, South pole, and Ferraz). Although second maximum was found in January at the other stations, the maximum was not observed at Syowa Station.

  11. Study of the Relationship Between the Organizational Climate and the Campus Ethical Issues of Universities across the Taiwan Strait

    Institute of Scientific and Technical Information of China (English)

    WU Chen-fong

    2004-01-01

    The study applied the approach of empirical studies to select 176 teachers in 9 universities in Taiwan and Inland in China to deliver questionnaires. The study intended to explore the influence of organizational climate on campus ethics and its diversity between the universities across the Taiwan strait. The study explored that the organizational climate in the universities across the Strait was not ethically high. Yet, the universities in Inland emphasized more on campus restraint in teachers' behavior, job performance and their sense of belonging to the school.The study result demonstrated that improving leadership of the universities could enhance teachers' identification with their schools and could promote the level of campus across the Strait.

  12. Recent summer sea ice thickness surveys in the Fram Strait and associated volume fluxes

    Directory of Open Access Journals (Sweden)

    T. Krumpen

    2015-09-01

    Full Text Available Fram Strait is the main gateway for sea ice export out of the Arctic Ocean, and therefore observations there give insight into composition and properties of Arctic sea ice in general and how it varies over time. An extensive data set of ground-based and airborne electromagnetic ice thickness measurements collected between 2001 and 2012 is presented here, including long transects well into the southern part of the Transpolar Drift obtained using fixed-wing aircrafts. The source area for the surveyed ice is primarily the Laptev Sea, and the estimated age is consistent with a decreased from 3 to 2 years between 1990 and 2012. The data consistently also show a general thinning for the last decade, with a decrease in modal thickness of second year and multiyear ice, and a decrease in mean thickness and fraction of ice thicker than 3 m. Local melting in the strait was investigated in two surveys performed in the downstream direction, showing a decrease of 0.19 m degree−1 latitude south of 81° N probably driven by bottom melting from warm water of Atlantic origin. Further north variability in ice thickness is more related to differences in age and deformation. The thickness observations were combined with ice area export estimates to calculate summer volume fluxes of sea ice. This shows that it is possible to determine volume fluxes through Fram Strait during summer when satellite based sea ice thickness information is missing. While the ice area export based on satellite remote sensing shows positive trends since 2001, the mean fluxes during summer (July and August are small (18 km3, and long-term trends are uncertain due to the limited surveys available.

  13. Potential Polyunsaturated Aldehydes in the Strait of Gibraltar under Two Tidal Regimes

    Directory of Open Access Journals (Sweden)

    Soledad Morillo-García

    2014-03-01

    Full Text Available Diatoms, a major component of the large-sized phytoplankton, are able to produce and release polyunsaturated aldehydes after cell disruption (potential PUAs or pPUA. These organisms are dominant in the large phytoplankton fraction (>10 µm in the Strait of Gibraltar, the only connection between the Mediterranean Sea and the Atlantic Ocean. In this area, the hydrodynamics exerts a strong control on the composition and physiological state of the phytoplankton. This environment offers a great opportunity to analyze and compare the little known distribution of larger sized PUA producers in nature and, moreover, to study how environmental variables could affect the ranges and potential distribution of these compounds. Our results showed that, at both tidal regimes studied (Spring and Neap tides, diatoms in the Strait of Gibraltar are able to produce three aldehydes: Heptadienal, Octadienal and Decadienal, with a significant dominance of Decadienal production. The PUA released by mechanical cell disruption of large-sized collected cells (pPUA ranged from 0.01 to 12.3 pmol from cells in 1 L, and from 0.1 to 9.8 fmol cell−1. Tidal regime affected the abundance, distribution and the level of physiological stress of diatoms in the Strait. During Spring tides, diatoms were more abundant, usually grouped nearer the coastal basin and showed less physiological stress than during Neap tides. Our results suggest a significant general increase in the pPUA productivity with increasing physiological stress for the cell also significantly associated to low nitrate availability.

  14. Reconstruction of transports through the Strait of Gibraltar from limited observations

    Science.gov (United States)

    Jordà, G.; Sánchez-Román, A.; Gomis, D.

    2016-04-01

    Observing the water transports through the Strait of Gibraltar is a difficult task. Here we present a methodology aimed to obtain the inflow, outflow and net transport of water from the limited set of available observations, currently consisting of an upward looking ADCP deployed at Espartel sill, two tide gauges located at each side of the Strait and radars monitoring the surface velocities. More precisely, we reconstruct the velocity field over a vertical section across the Strait using a reduced order optimal interpolation technique fed with the spatial covariance patterns deduced from high resolution numerical simulations. As a first step we carry out some sensitivity experiments with synthetic data that demonstrate the high potential of the approach. The reconstruction methodology can reproduce very satisfactorily the variability of the transports with estimated correlations for the inflow, outflow and net over 0.9 in all the cases and estimated RMS errors of 0.03, 0.08 and 0.05 Sv, respectively. However, we have also found that the reconstruction is sensible to bias problems, mostly due to the sensitivity of the method to the differences between the statistics of the actual and modeled velocity profiles. The sensitivity experiments have been used to tune the parameters of the method and a reconstruction of actual monthly transports has been performed for the period 2004-2010 along with an estimate of the associated uncertainty. This reconstruction provides for the first time a multiannual time series of the inflow and the net transports solely based on in situ observations. Therefore it can be used as an independent estimate for the validation of numerical models and surface freshwater fluxes in the Mediterranean.

  15. Acoustic imaging of the Mediterranean water outflowing through the Strait of Gibraltar

    Science.gov (United States)

    Biescas Gorriz, Berta; Carniel, Sandro; Sallarès, Valentí; Rodriguez Ranero, Cesar

    2016-04-01

    Acoustic imaging of the Mediterranean water outflowing through the Strait of Gibraltar Berta Biescas (1), Sandro Carniel (2) , Valentí Sallarès (3) and Cesar R. Ranero(3) (1) Istituto di Scienze Marine, CNR, Bologna, Italy (2) Istituto di Scienze Marine, CNR, Venice, Italy (3) Institut de Ciències del Mar, CSIC, Barcelona, Spain Acoustic reflectivity acquired with multichannel seismic reflection (MCS) systems allow to detect and explore the thermohaline structure in the ocean with vertical and lateral resolutions in the order of 10 m, covering hundreds of kilometers in the lateral dimension and the full-depth water column. In this work we present a MCS 2D profile that crosses the Strait of Gibraltar, from the Alboran Sea to the internal Gulf of Cadiz (NE Atlantic Ocean). The MCS data was acquired during the Topomed-Gassis Cruise (European Science Foundation TopoEurope), which was carried out on board of the Spanish R/V Sarmiento de Gamboa in October 2011. The strong thermohaline contrast between the Mediterranean water and the Atlantic water, characterizes this area and allows to visualize, with unprecedented resolution, the acoustic reflectivity associated to the dense flow of the Mediterranean water outflowing through the prominent slope of the Strait of Gibraltar. During the first kilometers, the dense flow drops attached to the continental slope until it reaches the buoyancy depth at 700 m. Then, it detaches from the sea floor and continues flowing towards the Atlantic Ocean, occupying the layer at 700-1500 m deep and developing clear staircase layers. The reflectivity images display near seabed reflections that could well correspond to turbidity layers. The XBT data acquired coincident in time and space with the MCS data will help us in the interpretation and analysis of the acoustic data.

  16. Performance Evaluation of HYCOM-GOM for Hydrokinetic Resource Assessment in the Florida Strait

    Energy Technology Data Exchange (ETDEWEB)

    Neary, Vincent S [ORNL; Gunawan, Budi [ORNL; Ryou, Albert S [ORNL

    2012-06-01

    The U.S. Department of Energy (DoE) is assessing and mapping the potential off-shore ocean current hydrokinetic energy resources along the U.S. coastline, excluding tidal currents, to facilitate market penetration of water power technologies. This resource assessment includes information on the temporal and three-dimensional spatial distribution of the daily averaged power density, and the overall theoretical hydrokinetic energy production, based on modeled historical simulations spanning a 7-year period of record using HYCOM-GOM, an ocean current observation assimilation model that generates a spatially distributed three-dimensional representation of daily averaged horizontal current magnitude and direction time series from which power density time series and their statistics can be derived. This study ascertains the deviation of HYCOM-GOM outputs, including transport (flow) and power density, from outputs based on three independent observation sources to evaluate HYCOM-GOM performance. The three independent data sources include NOAA s submarine cable data of transport, ADCP data at a high power density location, and HF radar data in the high power density region of the Florida Strait. Comparisons with these three independent observation sets indicate discrepancies with HYCOM model outputs, but overall indicate that the HYCOM-GOM model can provide an adequate assessment of the ocean current hydrokinetic resource in high power density regions like the Florida Strait. Additional independent observational data, in particular stationary ADCP measurements, would be useful for expanding this model performance evaluation study. ADCP measurements are rare in ocean environments not influenced by tides, and limited to one location in the Florida Strait. HF radar data, although providing great spatial coverage, is limited to surface currents only.

  17. Population ecology of polar bears in Davis Strait, Canada and Greenland

    Science.gov (United States)

    Peacock, Elizabeth; Taylor, Mitchell K.; Laake, Jeffrey L.; Stirling, Ian

    2013-01-01

    Until recently, the sea ice habitat of polar bears was understood to be variable, but environmental variability was considered to be cyclic or random, rather than progressive. Harvested populations were believed to be at levels where density effects were considered not significant. However, because we now understand that polar bear demography can also be influenced by progressive change in the environment, and some populations have increased to greater densities than historically lower numbers, a broader suite of factors should be considered in demographic studies and management. We analyzed 35 years of capture and harvest data from the polar bear (Ursus maritimus) subpopulation in Davis Strait, including data from a new study (2005–2007), to quantify its current demography. We estimated the population size in 2007 to be 2,158 ± 180 (SE), a likely increase from the 1970s. We detected variation in survival, reproductive rates, and age-structure of polar bears from geographic sub-regions. Survival and reproduction of bears in southern Davis Strait was greater than in the north and tied to a concurrent dramatic increase in breeding harp seals (Pagophilus groenlandicus) in Labrador. The most supported survival models contained geographic and temporal variables. Harp seal abundance was significantly related to polar bear survival. Our estimates of declining harvest recovery rate, and increasing total survival, suggest that the rate of harvest declined over time. Low recruitment rates, average adult survival rates, and high population density, in an environment of high prey density, but deteriorating and variable ice conditions, currently characterize the Davis Strait polar bears. Low reproductive rates may reflect negative effects of greater densities or worsening ice conditions.

  18. Quantifying submarine landslide processes driven by active tectonic forcing: Cook Strait submarine canyon, New Zealand.

    Science.gov (United States)

    Mountjoy, J. J.; Barnes, P. M.; Pettinga, J. R.

    2006-12-01

    The Cook Strait submarine canyon system is a multi-branched, deeply incised and highly sinuous feature of New Zealand's active margin, covering some 1500km2 of sea floor between the North and South Islands and spanning water depths of between 50 and 2700m. The canyon occurs at the transition from the westward dipping oblique subduction zone adjacent to the SE North Island and the zone of continental transpression in NE South Island. The recent acquisition of high resolution (5-10m) SIMRAD EM300 bathymetric data allows active tectonic and geomorphic processes to be assessed and quantified at a level of detail previously not possible. While multiple active submarine fault traces have been identified in the Cook Strait by previous studies, quantitative information on their activity has been limited. Cook Strait is structurally characterized by westward dipping thrust faults and E-W trending dextral strike slip faults. The multiple large magnitude high frequency earthquake sources define zones of very high ground shaking expected to contribute to triggering of extensive submarine slope failures. Landslide activity within the canyon system is widespread and represents the dominant mass movement process affecting canyon heads and walls, redistributing material into valley fills. Complexes of large (km3) multi-stepped, deep-seated (100m) translational bedding plane failures represented by gently sloping (<3°) evacuated slide-scar areas with associated blocky valley fill deposits are numerous. Steep catchment heads, channel walls and the leading edges of asymmetric thrust-fault driven anticlines are dominated by gulley and rill systems with associated eroded and/or incipient slump features. Large (107m3+) slide blocks are recognized in discrete failures with quantifiable displacement vectors. Tsunamigenic landslides in this environment are inevitable. This study will provide quantification of landslide models including triggering mechanisms, discrete geometries and

  19. Delivery of eye and vision services in Aboriginal and Torres Strait Islander primary health care centres

    Directory of Open Access Journals (Sweden)

    Anthea M Burnett

    2016-12-01

    Full Text Available Background: Routine eye and vision assessments are vital for the detection and subsequent management of vision loss, which is particularly important for Aboriginal and Torres Strait Islander people, who face higher rates of vision loss than other Australians. In order to guide improvements, this paper will describe patterns, variations and gaps in these eye and vision assessments for Aboriginal and Torres Strait Islander people. Methods: Clinical audits from 124 primary health care centres (sample size 15,175 from five Australian States and Territories were conducted during 2005-2012. Main outcome measure was adherence to current guidelines for delivery of eye and vision assessments to adults with diabetes, those without a diagnosed major chronic disease and children attending primary health care centres. Results: Overall delivery of recommended eye and vision assessments varied widely between health centres. Of the adults with diabetes, 45% had a visual acuity assessment recorded within the previous 12 months (health centre range 0-88%, and 33% had a retinal examination recorded (health centre range 0-73%. Of the adults with no diagnosed major chronic disease, 31% had a visual acuity assessment recorded within the previous two years (health centre range 0-30%, and 13% had received an examination for trichiasis (health centre range 0-40%. In children, 49% had a record of a vision assessment (health centre range 0-97%, and 25% had a record of an examination for trachoma within the previous 12 months (health centre range 0-63%. Conclusions: There was considerable range, and variation in the recorded delivery of scheduled eye and vision assessments across health centres. Sharing the successful strategies of the better-performing health centres to support focused improvements in key areas of need may increase overall rates of eye examinations – important for the timely detection, referral and treatment of eye conditions affecting Aboriginal and

  20. Psychrotrophic ~Iydrolytic Bacteria from Antarctica &,Other I. Low Temperature Habitats

    Directory of Open Access Journals (Sweden)

    K.V. Ramana

    2000-04-01

    Full Text Available Samples of water, soil,llake sediments and blue-green algal mats from Antarctica were'processed for enumeration, isolation and screening of psychrotrophic hydrolytic bacteria. Amylolytic bacteria were preponderant (75 per cent in the blue-green algal htat samples. Protease, lipase, an1ylase and urerse producing/bacteria were also isolated from the samples. ,Biochemical characteristics indicated that the isolates ;mainly comprised Pseudomonas and Bacillus species. Proteases and lipases of antarctic bacterial strains preferably hydrolysed denatured protein substrate and water soluble monomeric synthetic lipid substrates, respectively.

  1. Meteorites from Grove Mountains, Antarctica:An overview

    Institute of Scientific and Technical Information of China (English)

    王道德; 林杨挺

    2003-01-01

    Thirty-two meteorites were collected in Grove Mountains area, Antarctica,by the 15th and 16th Chinese Antarctic Research Expeditions (CHINARE). Petrography and mineral chemistry of these meteorites are reviewed, among which there are one Martian lherzolite, one eucrite, one ungrouped iron meteorite, and six unequilibrated and twenty-three equilibrated ordinary chondrites. An equilibrated ordinary chondrite GRV 98004 (H5) has an unusually low cosmic-ray exposure age. Meteorite concentrating processes in Grove Mountains area are discussed. In addition, future studies on Grove Mountains (GRV) meteorites are proposed.

  2. An assessment of forward and inverse GIA solutions for Antarctica

    Science.gov (United States)

    Bamber, Jonathan L.; Martin, Alba; King, Matt; Zammit-Mangion, Andrew

    2016-04-01

    GIA has, until recently, been estimated using forward models that attempt to determine how the solid Earth responds to changes in ice-ocean loading through time. These models require knowledge of spatially-varying Earth rheology, including mantle viscosity, and ice load history, both of which have large uncertainties for Antarctica. Recent advances in GIA models include consideration of three-dimensional variations in Earth rheology and power-law rheologies. Such GIA models predict remarkably different patterns of uplift over Antarctica when compared to those using one-dimensional Earth models, such as a shift in the uplift maximum from the Ross to the Wedell Sea (van der Wal et al., 2015). However, large uncertainties still remain in the ice loading history models (A. et al 2014 and van der Wal et al., 2015) and substantial regional differences are found between Antarctic reconstructions. An alternative approach is to use observations of crustal motion from GPS, combined with mass trends from GRACE to invert for GIA. However, this is an undetermined problem which requires assumptions on the density profile of the ice column for which numerical models have been commonly used (Gunter el al., 2014). Here we present a novel solution to the inverse problem using state-of-the-art methods in statistical modelling of spatio-temporal processes. Specifically, we combine observational data, including satellite radar and laser altimetry, GRACE, GPS and InSAR, with prior information on the spatial and temporal smoothness of the underlying process to solve, simultaneously, for ice mass trends and GIA. This is achieved via a spatio-temporal Bayesian hierarchical model and the resulting solution is only dependent on length and smoothness properties obtained from numerical models, but is otherwise entirely data-driven. We compare the most recent forward and inverse GIA solutions for Antarctica with a set of 68 observed vertical velocities over the period 2009 -- 2014 from the GPS

  3. Advanced systems data for mapping Emperor Penguin habitats in Antarctica

    Science.gov (United States)

    Sanchez, Richard D.; Kooyman, Gerald L.

    2004-01-01

    Commercial orbital sensor systems combined with other resource data from the U.S. Geological Survey National Civil Applications Program (NCAP) may offer an effective way of mapping Emperor penguin habitats and their response to regional climate change in Antarctica. This project examined these resources to determine their applicability for mapping Emperor penguin habitats to support the National Science Foundation. This work is especially significant to investigate satellite-based imaging as an alternative to intrusive in-the-field enumeration of Emperor penguins and the potential of applying these procedures to support The National Map (TNP).

  4. Wind power in Antarctica - a feasibility study for Wasa

    Energy Technology Data Exchange (ETDEWEB)

    Lindquist, Anna [Uppsala Univ. (Sweden). Div. for Electricity and Lightning Research

    2004-07-01

    The Swedish Polar Research Secretariat maintains two research stations in Antarctica, Wasa and Svea. They are both small, summer-only stations that are manned a few months at a time during the regular expeditions to the continent. Recently, Swedish scientists asked for the possibility to make around-the-year measurements with automatic equipment at the two stations. Since Wasa and Svea are only manned occasionally, this request implies the need for a new power supply system. The demands imposed on this new, separate system are hard. The continent is the coldest, windiest and driest on earth and the power supply system must be designed to withstand the harsh conditions. Since there is no personnel present during the Antarctic winter, the system also has to be autonomous and very reliable. The environment in Antarctica is sensitive and protected by strict regulations that all members of the Antarctic Treaty are obliged to follow. More and more nations are revising their power supply systems in order to find substitutions for the conventional diesel generators, and wind power has been installed at several stations and has worked well in many cases. This master thesis project is a feasibility study aimed at investigating whether wind power is a convenient solution in a separate power supply system at Wasa. During the project, wind data from weather stations in Antarctica have been used to map the wind resources at the two research stations. Although more accurate wind measurements would be needed for a complete evaluation of the wind resources, it can be seen that the prerequisites for wind power are good at Wasa. The wind is very directional, the wind speeds are moderate and the temperatures not too low. A wind turbine modified for the climate in Antarctica should function well at Wasa, in combination with a battery bank with NiCd batteries. Two turbines that fulfil most of the demands imposed on them and that seem to perform well in the conditions at Wasa were found

  5. Accelerated sea-level rise from West Antarctica.

    OpenAIRE

    Thomas, R; Rignot, E.; Casassa, G; Kanagaratnam, P; Acuña, C; Akins, T; Brecher, H; E Frederick; Gogineni, P.; Krabill, W.; Manizade, S.; Ramamoorthy, H; Rivera, A.; Russell, R.; Sonntag, J

    2004-01-01

    Recent aircraft and satellite laser altimeter surveys of the Amundsen Sea sector of West Antarctica show that local glaciers are discharging about 250 cubic kilometers of ice per year to the ocean, almost 60% more than is accumulated within their catchment basins. This discharge is sufficient to raise sea level by more than 0.2 millimeters per year. Glacier thinning rates near the coast during 2002-2003 are much larger than those observed during the 1990s. Most of these glaciers flow into flo...

  6. GIS-ILA:THE GIS FOR ITALIAN LOGISTICS IN ANTARCTICA

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A geographic information system (GIS) is a hardware/software tool which is very effective in collecting,storing,searching,handling,and visualizing geographic data together with their descriptive attributes.Such a tool is very helpful to approach a wide range of situations,including many logistic problems.ENEA,as the agency having the task of implementing the Italian Antarctic Program (PNRA),has decided to use a GIS,in order to increase the efficiency in managing the huge amount of data collected in the course of Italian activity in Antarctica,which counts fifteen expeditions up to now.

  7. Detection of evolutionarily distinct avian influenza a viruses in antarctica.

    Science.gov (United States)

    Hurt, Aeron C; Vijaykrishna, Dhanasekaran; Butler, Jeffrey; Baas, Chantal; Maurer-Stroh, Sebastian; Silva-de-la-Fuente, M Carolina; Medina-Vogel, Gonzalo; Olsen, Bjorn; Kelso, Anne; Barr, Ian G; González-Acuña, Daniel

    2014-05-06

    ABSTRACT Distinct lineages of avian influenza viruses (AIVs) are harbored by spatially segregated birds, yet significant surveillance gaps exist around the globe. Virtually nothing is known from the Antarctic. Using virus culture, molecular analysis, full genome sequencing, and serology of samples from Adélie penguins in Antarctica, we confirmed infection by H11N2 subtype AIVs. Their genetic segments were distinct from all known contemporary influenza viruses, including South American AIVs, suggesting spatial separation from other lineages. Only in the matrix and polymerase acidic gene phylogenies did the Antarctic sequences form a sister relationship to South American AIVs, whereas distant phylogenetic relationships were evident in all other gene segments. Interestingly, their neuraminidase genes formed a distant relationship to all avian and human influenza lineages, and the polymerase basic 1 and polymerase acidic formed a sister relationship to the equine H3N8 influenza virus lineage that emerged during 1963 and whose avian origins were previously unknown. We also estimated that each gene segment had diverged for 49 to 80 years from its most closely related sequences, highlighting a significant gap in our AIV knowledge in the region. We also show that the receptor binding properties of the H11N2 viruses are predominantly avian and that they were unable to replicate efficiently in experimentally inoculated ferrets, suggesting their continuous evolution in avian hosts. These findings add substantially to our understanding of both the ecology and the intra- and intercontinental movement of Antarctic AIVs and highlight the potential risk of an incursion of highly pathogenic AIVs into this fragile environment. IMPORTANCE Avian influenza viruses (AIVs) are typically maintained and spread by migratory birds, resulting in the existence of distinctly different viruses around the world. However, AIVs have not previously been detected in Antarctica. In this study, we

  8. Summer weather characteristics on the Grove Mountain of East Antarctica

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The summer weather characteristics of the Grove Mountain, East Antarctica, are presented based on the data obtained by Chinese National Antarctic Expedition (CHINARE) in January 1999. The result shows that the pattern of daily variation of temperature and the prevailing wind direction in Grove is similar to that of Zhongshan Station. However, the daily range of temperature and strong wind frequency are much higher than those of Zhongshan Station. The change of wind direction is close to the weather system that impacted the Grove Mountain. The warm and wet air from northern parts often causes the precipitation. The clear weather appears when controlled by eastern winds in January.

  9. Triassic leech cocoon from Antarctica contains fossil bell animal

    DEFF Research Database (Denmark)

    Bomfleur, Benjamin; Kerp, Hans; Taylor, Thomas N.

    2012-01-01

    Our understanding of the evolution of life on Earth is limited by the imperfection of the fossil record. One reason for this imperfect record is that organisms without hard parts, such as bones, shells, and wood, have a very low potential to enter the fossil record. Occasionally, however......, exceptional fossil deposits that preserve soft-bodied organisms provide a rare glimpse of the true biodiversity during past periods of Earth history. We here present an extraordinary find of a fossil ciliate that is encased inside the wall layer of a more than 200 Ma leech cocoon from Antarctica...

  10. Application of chemometric studies to metal concentrations in molluscs from the Strait of Magellan (Chile).

    Science.gov (United States)

    España, M S Astorga; Rodríguez, E M Rodríguez; Romero, C Díaz

    2007-05-01

    Na, K, Ca, Mg, Fe, Cu, Zn, Mn, Se, Ni, and Cd concentrations were determined in 126 mollusc samples belonging to five different species (Mytilus chilensis, n = 47; Nacella deaurata, n = 65; Aulacomya ater, n = 4; Fissurella picta, n = 4; Acanthina monodon, n = 6) collected from the coasts of the Strait of Magellan. The metals analysed presented significant differences between the mean concentrations for the mollusc species considered. Factor and discriminant analyses made possible the differentiation of the mollusc species. In addition, when discriminant analysis was used, good classifications were obtained according to sampling zone and weight-to-length ratio of the organisms.

  11. On the Mechanisms of Episodic Salinity Outflow Events in the Strait of Hormuz

    Science.gov (United States)

    2008-12-18

    ronmental Model (GDEM3) seasonally varying clima - tology with an {’-folding time scale of 1-76 days. The monthly river inflow into the basin is...noted that in all simulations sea sur- face salinity is restored to the GDEM3 monthly clima - tology with a time scale of ~30 days. As a result, the...strait at the southern part of the channel joins the inflow from the Gulf of Oman. The eastern extent of this returning flow shows high temporal vari

  12. Water mass distribution in Fram Strait and over the Yermak Plateau in summer 1997

    Directory of Open Access Journals (Sweden)

    B. Rudels

    Full Text Available The water mass distribution in northern Fram Strait and over the Yermak Plateau in summer 1997 is described using CTD data from two cruises in the area. The West Spitsbergen Current was found to split, one part recirculated towards the west, while the other part, on entering the Arctic Ocean separated into two branches. The main inflow of Atlantic Water followed the Svalbard continental slope eastward, while a second, narrower, branch stayed west and north of the Yermak Plateau. The water column above the southeastern flank of the Yermak Plateau was distinctly colder and less saline than the two inflow branches. Immediately west of the outer inflow branch comparatively high temperatures in the Atlantic Layer suggested that a part of the extraordinarily warm Atlantic Water, observed in the boundary current in the Eurasian Basin in the early 1990s, was now returning, within the Eurasian Basin, toward Fram Strait. The upper layer west of the Yermak Plateau was cold, deep and comparably saline, similar to what has recently been observed in the interior Eurasian Basin. Closer to the Greenland continental slope the salinity of the upper layer became much lower, and the temperature maximum of the Atlantic Layer was occasionally below 
    0.5 °C, indicating water masses mainly derived from the Canadian Basin. This implies that the warm pulse of Atlantic Water had not yet made a complete circuit around the Arctic Ocean. The Atlantic Water of the West Spitsbergen Current recirculating within the strait did not extend as far towards Greenland as in the 1980s, leaving a broader passage for waters from the Atlantic and intermediate layers, exiting the Arctic Ocean. A possible interpretation is that the circulation pattern alternates between a strong recirculation of the West Spitsbergen Current in the strait, and a larger exchange of Atlantic Water between the Nordic Seas and the inner parts of the Arctic Ocean.

    Key words: Oceanography: general

  13. Gibraltar Experiment: A Plan for Dynamic and Kinematic Investigations of Strait Mixing, Exchange and Turbulence

    Science.gov (United States)

    1985-08-01

    Garcia, M2 J. Garcia Objetivos . - 1) Anfilisis armo’nico de mareas registradas en Ceuta, Tarifa, Tra- falgar y Pta. Carnero, 2). Correlaci 6 n entre...pr-ograma ha sido financiado por SECEG. L -~ f. o; soP j!", 58 M~AREAS EN GIBRALTAR Jos6 W~ Garcia Mor-6n, Jos6 L. L6pez Objetivos . - A) Estudio de...Gibraltar Strait. HIDROGRAFIA Gregoria Parrilla, Rafael Molina 6 Objetivos . - Las medidas hechas con el CTD servir n para los siguientes obje- tivos

  14. Sensitivity of the Denmark Strait Overflow to various parameterizations in a z-coordinate numerical model

    Science.gov (United States)

    Colombo, Pedro; Barnier, Bernard; Penduff, Thierry; Molines, Jean-Marc

    2016-04-01

    Overflows play a key role in the climate system by ventilating deep waters, feeding boundary currents and determining the stratification of the deep ocean. Their correct representation is still an open issue in geopotential-coordinate global ocean models, and leads to misrepresentations of deep and bottom water masses. In this work we quantify the sensitivity of a realistic Denmark Strait regional configuration of the NEMO OGCM at 1/12° horizontal resolution to various parameters: partial vs full cells, use of a bottom boundary layer parameterization, and vertical resolution. We also provide a quantification of the spurious dyapicnal mixing present in the overflow through a passive tracer online release experiment.

  15. Transient tracer distributions in the Fram Strait in 2012 and inferred anthropogenic carbon content and transport

    Science.gov (United States)

    Stöven, Tim; Tanhua, Toste; Hoppema, Mario; von Appen, Wilken-Jon

    2016-02-01

    The storage of anthropogenic carbon in the ocean's interior is an important process which modulates the increasing carbon dioxide concentrations in the atmosphere. The polar regions are expected to be net sinks for anthropogenic carbon. Transport estimates of dissolved inorganic carbon and the anthropogenic offset can thus provide information about the magnitude of the corresponding storage processes. Here we present a transient tracer, dissolved inorganic carbon (DIC) and total alkalinity (TA) data set along 78°50' N sampled in the Fram Strait in 2012. A theory on tracer relationships is introduced, which allows for an application of the inverse-Gaussian-transit-time distribution (IG-TTD) at high latitudes and the estimation of anthropogenic carbon concentrations. Mean current velocity measurements along the same section from 2002-2010 were used to estimate the net flux of DIC and anthropogenic carbon by the boundary currents above 840 m through the Fram Strait. The new theory explains the differences between the theoretical (IG-TTD-based) tracer age relationship and the specific tracer age relationship of the field data, by saturation effects during water mass formation and/or the deliberate release experiment of SF6 in the Greenland Sea in 1996, rather than by different mixing or ventilation processes. Based on this assumption, a maximum SF6 excess of 0.5-0.8 fmol kg-1 was determined in the Fram Strait at intermediate depths (500-1600 m). The anthropogenic carbon concentrations are 50-55 µmol kg-1 in the Atlantic Water/Recirculating Atlantic Water, 40-45 µmol kg-1 in the Polar Surface Water/warm Polar Surface Water and between 10 and 35 µmol kg-1 in the deeper water layers, with lowest concentrations in the bottom layer. The net fluxes through the Fram Strait indicate a net outflow of ˜ 0.4 DIC and ˜ 0.01 PgC yr-1 anthropogenic carbon from the Arctic Ocean into the North Atlantic, albeit with high uncertainties.

  16. A Fram Strait Experiment: Sensing Sea Ice Conditions using Shipborne GNSS Reflectometry

    Science.gov (United States)

    Semmling, Maximilian; Rösel, Anja; Ludwig, Marcel; Bratrein, Marius; Gerland, Sebastian; Wickert, Jens

    2017-04-01

    Cruises of the Norwegian research vessel (R/V) Lance provide regular in-situ measurements of ocean and sea ice properties in Fram Strait, at the major link between the Arctic and the Atlantic Ocean. A GNSS reflectometry (GNSS-R) setup has been installed aboard R/V Lance to investigate sea ice remote sensing opportunities during the Fram Strait 2016 cruise. The experiment is based on previous coastal investigations, which demonstrated the ocean altimetric potential of GNSS-R and its sensitivity to the sea ice cover. The presence of sea ice can be detected by the reduced sea surface roughness that affects the coherence of the GNSS-R carrier phase. Differential phase observations of the reflected signal relative to the direct signal are considered here. The objective of this study is the retrieval of the coherent differential phase resolving the altimetric effect of changes in the sea ice thickness. Grazing reflections with satellite elevations GNSS signals introduces significant biases in the differential phase especially at grazing elevations. The shipborne setup with antenna heights of 24 m above sea level allows to study grazing reflections disregarding the atmospheric bias. The setup slightly differs from common shipborne GNSS equipment. It consists of a GORS (GNSS Occultation Reflectometry Scatterometry) receiver, based on commercial JAVAD hardware. Two antenna links are starbord-looking with right- and left-handed circular polarization to detect the reflected signal. One right-handed antenna is up-looking for reference to the direct signal. In-phase and quadrature (I,Q) samples from the three antenna links were recorded during the entire Fram Strait cruise, between 25 August and 13 September 2016. The ship's track on its main section went from Svalbard at 10° E roughly along 79° N to the Eastern Greenland coast at 13° W and back. Different ice conditions were encountered: open water with a rough sea surface close to Svalbard, a dense coverage of multiyear

  17. On the origin and propagation of Denmark Strait Overflow Water Anomalies in the Irminger Basin

    Science.gov (United States)

    Jochumsen, Kerstin; Quadfasel, Detlef; Köllner, Manuela; Dye, Stephen; Rudels, Bert; Valdimarsson, Hedinn

    2015-04-01

    Denmark Strait Overflow Water (DSOW) supplies the densest contribution to North Atlantic Deep Water and is monitored at several locations in the subpolar North Atlantic. We present an analysis of observed hydrographic (temperature and salinity) and velocity time series from three multiple-mooring arrays to quantify the variability and to track anomalies of DSOW: (1) at the Denmark Strait sill, (2) at 180 km downstream (south of Dohrn Bank) and (3) at a further 320 km downstream on the east Greenland continental slope near Tasiilaq (formerly Angmagssalik). The aim of the combined arrays is to cover the overflow plume and its modifications due to its descent and mixing with ambient waters from the sill of Denmark Strait to approx. 2000 m depth in the northern Irminger Basin. Eddy variability dominates the high frequency variations in all DSOW records. Variability on time scales from interannual to weekly is present at all moorings, but no long term trends are detected in the time series. The seasonal cycle is of no importance for the properties measured at the sill, but its significance increases with downstream distance. A low pass filter (cut-off at 20 days) is applied to the time series in order to remove synoptic scale variations: single eddies are likely not traceable and probably merge with each other or fade along the descending pathway of the DSOW plume. The hydrographic time series from different moorings within each mooring array show coherent signals, while the velocity fluctuations are only weakly correlated. Lagged correlations of anomalies between the arrays reveal propagation from the sill of Denmark Strait to the Angmagssalik array in potential temperature with an average propagation time of 16 days. Despite a difference of 1.5°C between the mean temperatures at both arrays, which are about 500 km away from each other, temperature anomalies can be traced along the DSOW pathway. In contrast, the correlations in salinity are low and only significant

  18. High risk alcohol-related trauma among the Aboriginal and Torres Strait Islanders in the Northern Territory.

    Science.gov (United States)

    Jayaraj, Rama; Thomas, Mahiban; Thomson, Valerie; Griffin, Carolyn; Mayo, Luke; Whitty, Megan; d'Abbs, Peter; Nagel, Tricia

    2012-08-03

    High risk drinking is linked with high rates of physical harm. The reported incidence of alcohol - related trauma among Aboriginal and Torres Strait Islander people in the Northern Territory is the highest in the world. Facial fractures are common among young Aboriginal and Torres Strait Islanders. They are often linked with misuse of alcohol in the Northern Territory and are frequently secondary to assault. This review focuses on alcohol-related trauma in the Territory and draws attention to an urgent need for preventative health approach to address this critical issue.

  19. On the variability of Florida Straits and wind driven transports at 26° N in the Atlantic Ocean

    Directory of Open Access Journals (Sweden)

    T. Kanzow

    2010-04-01

    Full Text Available Since April 2004 the RAPID array has made continuous measurements of the Atlantic Meridional Overturning Circulation (AMOC at 26° N. Two key components of this system are Ekman transport zonally integrated across 26° N and western boundary current transport in the Florida Straits. Whilst measurements of the AMOC as a whole are somewhat in their infancy, this study investigates what useful information can be extracted on the variability of the Ekman and Florida Straits transports using the decadal timeseries already available. Analysis is also presented for Sverdrup transports zonally integrated across 26° N. The seasonal cycles of Florida Straits, Ekman and Sverdrup transports are quantified at 26° N using harmonic analysis of annual and semi-annual constituents. Whilst Sverdrup transport shows clear semi-annual periodicity, calculations of seasonal Florida Straits and Ekman transports show substantial interannual variability due to variability at non-seasonal frequencies; the mean seasonal cycle for these transports only emerges from decadal length observations. The Florida Straits and Ekman mean seasonal cycles project on the AMOC with a combined peak-to-peak seasonal range of 3.5 Sv. The combined seasonal range for heat transport is 0.40 PW. The Florida Straits seasonal cycle possesses a smooth annual periodicity in contrast with previous studies suggesting a more asymmetric structure. No clear evidence is found to support significant changes in the Florida Straits seasonal cycle at sub-decadal periods. Whilst evidence of wind driven Florida Straits transport variability is seen at sub-seasonal and annual periods, model runs from the 1/4° eddy-permitting ocean model NEMO are used to identify an important contribution from internal oceanic variability at sub-annual and interannual periods. The Ekman transport seasonal cycle possesses less symmetric structure, due in part to different seasonal transport regimes east and west of 50 to 60

  20. Measurements of spectral snow albedo at Neumayer, Antarctica

    Directory of Open Access Journals (Sweden)

    S. Wuttke

    2006-03-01

    Full Text Available Spectral albedo in high resolution, from 290 to 1050 nm, has been measured at Neumayer, Antarctica, (70°39' S, 8°15' W during the austral summer 2003/2004. At 500 nm, the spectral albedo nearly reaches unity, with slightly lower values below and above 500 nm. Above 600 nm, the spectral albedo decreases to values between 0.45 and 0.75 at 1000 nm. For one cloudless case an albedo up to 1.01 at 500 nm could be determined. This can be explained by the larger directional component of the snow reflectivity for direct incidence, combined with a slightly mislevelled sensor and the snow surface not being perfectly horizontal. A possible explanation for an observed decline in albedo is an increase in snow grain size. The theoretically predicted increase in albedo with increasing solar zenith angle (SZA could not be observed. This is explained by the small range of SZA during albedo measurements, combined with the effect of changing snow conditions outweighing the effect of changing SZA. The measured spectral albedo serves as input for radiative transfer models, describing radiation conditions in Antarctica.

  1. Chemical composition of the sediment from Lake 20 (Antarctica

    Directory of Open Access Journals (Sweden)

    Daria ROSSI

    2000-02-01

    Full Text Available Lake 20 (19,000 m2 is located on the coast of the Ross Sea, in the North-Central part of Victoria Land, and its surface is ice-free between the end of December and early February. Within the framework of the Italian National Research Programme in Antarctica, a study was made of the chemical composition of sediments from the lake, with the intention of using this information to contribute to a better understanding of the processes involved in the long range transport of pollutants and their role in global changes. A sediment core from Lake 20 (Antarctica, 18 cm long, was collected in 1994, sliced into 2 cm sections and analysed using X Ray fluorescence spectrometry for 17 elements (Si, Al, Ca, K, Fe, Mg, Ti, S, P, Pb, Zn, Cu, Ni, Mn, Cr, Na, Cl, by CHN Elemental Analyser for C and N, by Flameless Atomic Absorption Spectrometry for As, and by Cold Vapour Atomic Absorption Spectrometry for Hg. The chemical composition of the sediments is consistent with the known geochemical characteristics of the drainage basin. While the chemical analyses reveal that sedimentation in Lake 20 has changed through time, the variations along the core are most probably related to the climatic evolution of the area, to the consequent changes in weathering processes, and possibly to an increase in the primary productivity of the lake, rather than to anthropogenic influences on the biogeochemical cycles of the elements.

  2. Surface and snowdrift sublimation at Princess Elisabeth station, East Antarctica

    Directory of Open Access Journals (Sweden)

    W. Thiery

    2012-04-01

    Full Text Available In the near-coastal regions of Antarctica, a significant fraction of the snow precipitating onto the surface is removed again through sublimation – either directly from the surface or from drifting snow particles. Meteorological observations from an Automatic Weather Station (AWS near the Belgian research station Princess Elisabeth in Dronning Maud Land, East-Antarctica, are used to study surface and snowdrift sublimation and to assess their impacts on both the surface mass balance and the surface energy balance. Comparison to three other AWSs in Dronning Maud Land shows that sublimation has a significant influence on the surface mass balance at katabatic locations by removing 10–23 % of their total precipitation, but at the same time reveals anomalously low surface and snowdrift sublimation rates at Princess Elisabeth (18 mm w.e. yr–1 compared to 42 mm w.e. yr–1 at Svea Cross and 52 mm w.e. yr–1 at Wasa/Aboa. This anomaly is attributed to local topography, which shields the station from strong katabatic influence, and therefore on the one hand allows for a strong surface inversion to persist throughout most of the year and on the other hand causes a lower probability of occurrence of intermediately strong winds. These wind speed classes turn out to contribute most to the total snowdrift sublimation mass flux, given their ability to lift a high number of particles while still allowing for considerable undersaturation.

  3. Deep Drilling with the ANDRILL Program in Antarctica

    Directory of Open Access Journals (Sweden)

    Alex Pyne

    2006-09-01

    Full Text Available ANDRILL (ANtarctic geological DRILLing is a new international, multi-disciplinary drilling program that targets geological records that lie hidden beneath the icy blanket of Antarctica. The primary objective is to investigate Antarctica’s role in global environmental change over the past sixty-fi ve million years, at various scales of age resolution, and thereby enhance our understanding of Antarctica’s potential response to future global changes. Efforts to understand the infl uence of Antarctica on global climate change require a fundamental knowledge of how the Antarctic cryosphere (ice sheets, ice shelves, and sea ice has evolved, not only in recent times but also during earlier geological periods when global temperature and atmospheric CO2 levels were similar to what might be reached by the end of this century. ANDRILL’s integrated science approach willuse stratigraphic drilling, coring, and multi-proxy core analysis combined with geophysical surveys and numerical modeling to study the Cenozoic history of Antarctic climate and ice sheets, the evolution of polar biota, Antarctic tectonism, and Antarctica’s role in the evolution of Earth’s ocean–climate system.

  4. Chemical composition of fresh snowfalls at Palmer Station, Antarctica

    Science.gov (United States)

    DeFelice, T. P.

    A first time investigation was performed to establish a chemical baseline for snowfall at Palmer Station Antarctica (64°46'S, 64°05'W) since there was no such record. A chemical baseline for snow could be use to validate climate change studies based on ice core analyses. The snow samples contained (from high to low mass concentration) total organic carbon, chloride, inorganic carbon, sodium, sulfate, magnesium, calcium, potassium, fluoride, ammonium, and nitrate, excluding hydrogen and hydroxide. The pH of these samples ranged between 4.0-6.2. The relatively low nitrate and relatively high sulfate concentrations found in our samples are consistent with the results of other studies for this region of Antarctica. The ions and pH do not appear to favor a particular wind direction during this period. The total deposition of sulfate and flouride via snowfall between 10 January and 10 February is conservatively estimated to be 4.78 and 1.3 kg km -2, respectively.

  5. Ocean mixing beneath Pine Island Glacier ice shelf, West Antarctica

    Science.gov (United States)

    Kimura, Satoshi; Jenkins, Adrian; Dutrieux, Pierre; Forryan, Alexander; Naveira Garabato, Alberto C.; Firing, Yvonne

    2016-12-01

    Ice shelves around Antarctica are vulnerable to an increase in ocean-driven melting, with the melt rate depending on ocean temperature and the strength of flow inside the ice-shelf cavities. We present measurements of velocity, temperature, salinity, turbulent kinetic energy dissipation rate, and thermal variance dissipation rate beneath Pine Island Glacier ice shelf, West Antarctica. These measurements were obtained by CTD, ADCP, and turbulence sensors mounted on an Autonomous Underwater Vehicle (AUV). The highest turbulent kinetic energy dissipation rate is found near the grounding line. The thermal variance dissipation rate increases closer to the ice-shelf base, with a maximum value found ˜0.5 m away from the ice. The measurements of turbulent kinetic energy dissipation rate near the ice are used to estimate basal melting of the ice shelf. The dissipation-rate-based melt rate estimates is sensitive to the stability correction parameter in the linear approximation of universal function of the Monin-Obukhov similarity theory for stratified boundary layers. We argue that our estimates of basal melting from dissipation rates are within a range of previous estimates of basal melting.

  6. Properties of soils in Grove Mountains, East Antarctica

    Institute of Scientific and Technical Information of China (English)

    LI; Xiaoli(李潇丽); LIU; Xiaohan(刘小汉); JU; Yitai(琚宜太); HUANG; Feixin(黄费新)

    2003-01-01

    Three cold desert soil sites were first found in the southern Mount Harding, GroveMountains, East Antarctica. The soils are characteristics of the widespread occurrence of surfacedesert pavement, abundant water-soluble salts, strongly stained upper portion of soil profile,slightly acid and negligible organic matter content. A 1:5 soil-water extracts analysis indicates thatthe dominant cations are Mg2+ and Na+, followed by Ca2+ and K+, and the main anion is SO42-, thenCl- and NO-3. The accumulation of water-soluble salts indicates ion transportation in the frigid andarid Antarctica environment. The distribution of the salts is related to the maximum content ofmoisture and clay mineral. Clay fraction migration occurs in the soils, which is different from that ofother cold desert soils. The upper horizons of some profiles are generally stained, namely rubifica-tion, primarily because of the weathering of iron-bearing minerals. The reddish hues of cold desertsoils have been attributed to relatively high concentrations of dithionite-extractable Fe (Fed). Theweathering features of soils suggest that the soil age of this area is 0.5-3.5 Ma. No remnants ofglaciations were found on the soil sites of Mount Harding, which suggests that the Antarctic glaci-ations have not reached the soil sites since at least 0.5 Ma, even during the Last Glacial Maxi-mum.

  7. The larval alimentary canal of the Antarctic insect, Belgica antarctica.

    Science.gov (United States)

    Nardi, James B; Miller, Lou Ann; Bee, Charles Mark; Lee, Richard E; Denlinger, David L

    2009-09-01

    On the Antarctica continent the wingless midge, Belgica antarctica (Diptera, Chironomidae) occurs further south than any other insect. The digestive tract of the larval stage of Belgica that inhabits this extreme environment and feeds in detritus of penguin rookeries has been described for the first time. Ingested food passes through a foregut lumen and into a stomodeal valve representing an intussusception of the foregut into the midgut. A sharp discontinuity in microvillar length occurs at an interface separating relatively long microvilli of the stomodeal midgut region, the site where peritrophic membrane originates, from the midgut epithelium lying posterior to this stomodeal region. Although shapes of cells along the length of this non-stomodeal midgut epithelium are similar, the lengths of their microvilli increase over two orders of magnitude from anterior midgut to posterior midgut. Infoldings of the basal membranes also account for a greatly expanded interface between midgut cells and the hemocoel. The epithelial cells of the hindgut seem to be specialized for exchange of water with their environment, with the anterior two-thirds of the hindgut showing highly convoluted luminal membranes and the posterior third having a highly convoluted basal surface. The lumen of the middle third of the hindgut has a dense population of resident bacteria. Regenerative cells are scattered throughout the larval midgut epithelium. These presumably represent stem cells for the adult midgut, while a ring of cells, marked by a discontinuity in nuclear size at the midgut-hindgut interface, presumably represents stem cells for the adult hindgut.

  8. Transit Search from Antarctica and Chile - Comparison and Combination

    CERN Document Server

    Fruth, T; Csizmadia, Sz; Dreyer, C; Eigmüller, P; Erikson, A; Kabath, P; Pasternacki, T; Rauer, H; Titz-Weider, R; Abe, L; Agabi, A; Gonçalves, I; Guillot, T; Mékarnia, D; Rivet, J -P; Crouzet, N; Chini, R; Lemke, R; Murphy, M

    2014-01-01

    Observing sites at the East-Antarctic plateau are considered to provide exceptional conditions for astronomy. The aim of this work is to assess its potential for detecting transiting extrasolar planets through a comparison and combination of photometric data from Antarctica with time series from a midlatitude site. During 2010, the two small aperture telescopes ASTEP 400 (Dome C) and BEST II (Chile) together performed an observing campaign of two target fields and the transiting planet WASP-18b. For the latter, a bright star, Dome C appears to yield an advantageous signal-to-noise ratio. For field surveys, both Dome C and Chile appear to be of comparable photometric quality. However, within two weeks, observations at Dome C yield a transit detection efficiency that typically requires a whole observing season in Chile. For the first time, data from Antarctica and Chile have been combined to extent the observational duty cycle. This approach is both feasible in practice and favorable for transit search, as it i...

  9. Reactive chlorine chemistry in the boundary layer of coastal Antarctica

    Science.gov (United States)

    Zielcke, Johannes; Poehler, Denis; Friess, Udo; Hay, Tim; Eger, Philipp; Kreher, Karin; Platt, Ulrich

    2015-04-01

    A unique feature of the polar troposphere is the strong impact of halogen photochemistry, in which reactive halogen species are responsible for ozone depletion as well as the oxidation of elemental mercury and dimethyl sulphide. The source, however, as well as release and recycling mechanisms of these halogen species - for some species even abundances - are far from being completely known, especially of chlorine and iodine compounds. Here we present active long-path differential optical absorption spectroscopy (LP-DOAS) measurements conducted during austral spring 2012 at Ross Island, Antarctica, observing several species (BrO, O3, NO2, IO, ClO, OBrO, OClO, OIO, I2, CHOCHO, HCHO, HONO). For the first time, ClO was detected and quantified in the marine boundary layer of coastal Antarctica, with typical mixing ratios around 20 pptv and maxima around 50 pptv. Meteorological controls on the mixing ratio of ClO as well as the interplay with other halogen compounds will be discussed, such as the lack of observed OClO (< 1 pptv). The results seem to reflect previously in chamber studies observed dependences on ozone levels and solar irradiance.

  10. A numerical study of the South China Sea deep circulation and its relation to the Luzon Strait transport

    Institute of Scientific and Technical Information of China (English)

    袁东亮

    2002-01-01

    A fine-resolution MOM code is used to study the South China Sea basin-scale circulation and its relation to the mass transport through the Luzon Strait. The modal domain includes the South China Sea, part of the East China Sea, and part of the Philippine Sea so that the currents in the vicinity of the Luzon Strait are free to evolve. In addition, all channels between the South China ,Sea and the Indonesian seas are closed so that the focus is on the Luzon Strait transport. The model is driven by specified Philippine Sea currents and by surface heat and salt flux conditions. For simplicity, no windstress is applied at the surface.The simulated Luzon Strait transport and the South China Sea circulation feature a sandwich vertical structure from the surface to the bottom. The Philippine Sea water is simulated to enter the South China Sea at the surface and in the deep ocean and is carried to the southern basin by western boundary currents. At the intermediate depth, the net Luzon Strait transport is out of the South China Sea and is fed by a western boundary current flowing to the north at the base of the thermocline. Corresponding to the western boundary currents, the basin circulation of the South China Sea is cyclonic gyres at the surface and in the abyss but an anti-cyclonic gyre at the intermediate depth. The vorticity balance of the gyre circulation is between the vortex stretching and the meridional change of the planetary vorticity.Based on these facts, it is hypothesized that the Luzon Strait transports are determined by the diapycnal mixing inside the entire South China Sea. The South China Sea plays the role of a "mixing mill" that mixes the surface and deep waters to return them to the Luzon Strait at the intermediate depth. The gyre structures are consistent with the Stommel and Arons theory (1960), which suggests that the mixlng-induced circulation inside the South China Sea should be cyclonic gyres at the surface and at the bottom but an anti

  11. Coastal Erosion Along the West Coast of the Taiwan Strait and It's Influencing Factors

    Institute of Scientific and Technical Information of China (English)

    LIU Jianhui; CAI Feng; QI Hongshuai; LEI Gang; CAO Lihua

    2011-01-01

    Based on the field surveys and repeated cross-profile observations combined with the comparison of many years' topographic maps, this study shows the spatial variability and varying patterns of coastal erosion along the west coast of the Taiwan Strait. Regional differentiation in the Meso-Cenozoic coastal tectonics determined the irregular coastline and geological background for large-scale coastal erosion distribution. The intensity of coastal erosion on the west side of the Taiwan Strait is mild in the northern region, severe in the central region and modest in the southern region. The beaches along the coast are mainly backed by dunes, seawalls or cliffs. The dunes and beaches show periodic erosion and recovery along the coast adjacent to river mouths, while persistent retreat of frontal dunes and beaches tends to occur in other areas. The beach erosion occurs mainly in front of seawalls. Due to the low strength of the unconsolidated sediment the soft cliffs suffer the severest coastline recession. Sea level rise and river sediment discharge reduction are main causes of coastal erosion. Storm surge is common in the studied area and plays an important role in the progress of coastal erosion. Human activities including coastal constructions and sand mining also tend to interfere strongly with the balance of sediment budget in some coastal cells.

  12. Small-scale variability of the current in the Strait of Bonifacio

    Science.gov (United States)

    Gérigny, Olivia; Coudray, Sylvain; Lapucci, Chiara; Tomasino, Corinne; Bisgambiglia, Paul-Antoine; Galgani, François

    2015-08-01

    Current dynamics in the Strait of Bonifacio (south Corsica) were investigated at a small scale during the STELLAMARE1 multidisciplinary cruise in summer 2012, using in situ measurements and modeling data. The Strait of Bonifacio is a particularly sensitive marine area in which specific conservation measures have been taken to preserve the natural environment and wild species. Good knowledge of the hydrodynamics in this area is essential to optimize the Marine Protected Area's management rules. Therefore, we used a high-resolution model (400 m) based on the MARS3D code to investigate the main flux exchanges and to formulate certain hypotheses about the formation of possible eddy structures. The aim of the present paper is first to synthetize the results obtained by combining Acoustic Doppler Current Profiler data, hydrological parameters, Lagrangian drifter data, and satellite observations such as MODIS OC5 chlorophyll a data or Metop-A AVHRR Sea Surface Temperature (SST) data. These elements are then used to validate the presence of the mesoscale eddies simulated by the model and their recurrence outside the cruise period. To complete the analysis, the response of the 3D hydrodynamical model was evaluated under two opposing wind systems and certain biases were detected. Strong velocities up to 1 m s-1 were recorded in the east part due to the Venturi effect; a complementary system of vortices governed by Coriolis effect and west wind was observed in the west part, and horizontal stratification in the central part has been identified under typical wind condition.

  13. Recent observations of seasonal variability of the Mediterranean outflow in the Strait of Gibraltar

    Science.gov (United States)

    GarcíA Lafuente, J.; SáNchez RomáN, A.; DíAz Del RíO, G.; Sannino, G.; SáNchez Garrido, J. C.

    2007-10-01

    Recent observations of the outflowing Mediterranean water collected near the bottom in key points of the Strait of Gibraltar show the existence of a seasonal cycle with warmer and lighter waters leaving the Mediterranean Sea in winter and cooler and denser waters in spring early summer. The amplitude of the signal is around 5 10-2 °C for potential temperature and 1.5 10-2 for potential density, salinity hardly showing seasonal fluctuations. The outflow also shows a seasonal cycle with maximum volume transport in April, in coincidence with the minimum of the signal of potential temperature. A simple analysis of the composition of the outflow in terms of the main water masses of the western Mediterranean basin and its comparison with climate indicators suggests that the seasonal cycle follows the annual process of the Western Mediterranean Deep Water formation that replenish the deep portion of the basin by the end of winter and rises the level of the deep water reservoir, facilitating the suction of cooler and denser water from the Mediterranean over the sills of the Strait. From this time onwards, the data show a smooth warming that would be explained by the progressive fall of the level of the Western Mediterranean Deep Water as it is drained out the Mediterranean, which would leave warmer water available for suction. The process is asymmetric in the sense that the transition from high to low temperature is completed in a short period while the progressive warming spans a longer period.

  14. Assessment of pollution aerosols sources above the Straits of Dover using lead isotope geochemistry.

    Science.gov (United States)

    Deboudt, K; Flament, P; Weis, D; Mennessier, J P; Maquinghen, P

    1999-09-15

    We assess the capability of lead isotopes to study the transport of pollution aerosols above the Straits of Dover by collecting atmospheric aerosols above the Eastern Channel and the Southern Bight of the North Sea. During the same period, we characterized the lead isotopic signature of the main industrial sources on the French coast near the Straits of Dover. Urban and automobile-derived aerosols were also collected. Due to the phasing out of lead in gasoline, the urban isotopic composition (206Pb/207Pb = 1.158 +/- 0.003) has become more radiogenic, although it is highly variable. On a regional scale, major industrial emissions have a well-defined isotopic composition (1.13 isotopic compositions, it can be shown that lead aerosols originating from eastern Europe have an isotopic signature (1.145 isotopic composition of west-European lead aerosols (1.111 < 206Pb/207Pb < 1.142). The influence of remote North American sources is suggested, with caution, due to uncertainties in meteorological calculations.

  15. Sound speed as a proxy variable to temperature in Fram Strait.

    Science.gov (United States)

    Dushaw, Brian D; Sagen, Hanne; Beszczynska-Möller, Agnieszka

    2016-07-01

    The application of ocean acoustic tomography in Fram Strait requires a careful assessment of the accuracy to which estimates of sound speed from tomography can be converted to estimates of temperature. The Fram Strait environment is turbulent, with warm, salty, northward-flowing North Atlantic water interacting with cold, fresh, southward-flowing Arctic water. The nature of this environment suggests that salinity could play an important role with respect to sound speed. The properties of sound speed with respect to temperature and salinity in this environment were examined using climatological and in situ glider data. In cold water, a factor of about 4.5 m s(-1) °C(-1) can be used to scale between sound speed and temperature. In situ data obtained by gliders were used to determine the ambiguities between temperature, salinity, and sound speed. Tomography provides a depth-averaging measurement. While errors in the sound speed-temperature conversion at particular depths may be 0.2 °C or larger, particularly within 50 m of the surface, such errors are suppressed when the depth is averaged. Using a simple scale factor to compute temperature from sound speed introduced an error of about 20 m °C for depth-averaged temperature, a value less than formal uncertainties estimated from acoustic tomography.

  16. Surface circulation at the Strait of Gibraltar: A combined HF radar and high resolution model study

    Science.gov (United States)

    Soto-Navarro, Javier; Lorente, Pablo; Álvarez Fanjul, Enrique; Carlos Sánchez-Garrido, Jose; García-Lafuente, Jesús

    2016-03-01

    Observations from a high frequency radar system and outputs from a high resolution operational ocean model working at the Strait of Gibraltar have been analyzed and compared during the period February 2013 to September 2014 in order to evaluate their capability to resolve the surface circulation of the region. The description of the mean circulation patterns has been statistically assessed, showing good agreement, particularly in the central region of the strait corresponding with the Atlantic Jet (AJ) stream, although some short scale features are not reproduced by the model. In the frequency domain very high concordance is observed. Tidal maps of diurnal and semidiurnal constituents are in good agreement with previous observations. The analysis of the model and radar response to the wind forcing reveals that the low resolution of the model wind-forcing field and its deeper superficial level smoothes the wind effect on the simulated currents. The first three EOF modes account for the 86% of model and radar variances. The coincidence between the observed and simulated patterns is very significant for the first two modes, which account for the mean velocity field and the latitudinal shifting of the AJ consequence of the flow-topography interaction. The third mode captures the wind-induced circulation, and greater discrepancies are found in this case. Results underline the complementary character of both systems: radar observations improve the model description, resolving short scale processes, while the model completes the radar information when the time or spatial coverage is poorer.

  17. Mesoscale mixing of the Denmark Strait Overflow in the Irminger Basin

    Science.gov (United States)

    Koszalka, Inga M.; Haine, Thomas W. N.; Magaldi, Marcello G.

    2017-04-01

    The Denmark Strait Overflow (DSO) is a major export route for dense waters from the Nordic Seas forming the lower limb of the Atlantic Meridional Overturning Circulation, an important element of the climate system. Mixing processes along the DSO pathway influence its volume transport and properties contributing to the variability of the deep overturning circulation. They are poorly sampled by observations, however, which hinders development of a proper DSO representation in global circulation models. We employ a high resolution regional ocean model of the Irminger Basin to quantify impact of the mesoscale flows on DSO mixing focusing on geographical localization and the time-modulation of water property changes. The model reproduces the observed bulk warming of the DSO plume 100-200 km downstream of the Denmark Strait sill. It also reveals that mesoscale variability of the overflow ('DSO-eddies', of 20-30 km extent and a time scale of 2-5 day) modulates water property changes and turbulent mixing, diagnosed with the vertical shear of horizontal velocity and the eddy heat flux divergence. The space-time localization of the DSO mixing and warming and the role of coherent mesoscale structures should be explored by turbulence measurements and factored into the coarse circulation models.

  18. Tsunamigenic potential of a newly discovered active fault zone in the outer Messina Strait, Southern Italy

    Science.gov (United States)

    Fu, Lili; Heidarzadeh, Mohammad; Cukur, Deniz; Chiocci, Francesco L.; Ridente, Domenico; Gross, Felix; Bialas, Jörg; Krastel, Sebastian

    2017-03-01

    The 1908 Messina tsunami was the most catastrophic tsunami hitting the coastline of Southern Italy in the younger past. The source of this tsunami, however, is still heavily debated, and both rupture along a fault and a slope failure have been postulated as potential origin of the tsunami. Here we report a newly discovered active Fiumefreddo-Melito di Porto Salvo Fault Zone (F-MPS_FZ), which is located in the outer Messina Strait in a proposed landslide source area of the 1908 Messina tsunami. Tsunami modeling showed that this fault zone would produce devastating tsunamis by assuming slip amounts of ≥5 m. An assumed slip of up to 17 m could even generate a tsunami comparable to the 1908 Messina tsunami, but we do not consider the F-MPS_FZ as a source for the 1908 Messina tsunami because its E-W strike contradicts seismological observations of the 1908 Messina earthquake. Future researches on the F-MPS_FZ, however, may contribute to the tsunami risk assessment in the Messina Strait.

  19. Filament generation off the Strait of Gibraltar in response to Gap winds

    Science.gov (United States)

    Peliz, Álvaro; Teles-Machado, Ana; Marchesiello, Patrick; Dubert, Jesus; Lafuente, Jesus Garcia

    2009-01-01

    We present a case study of the generation of a cold filament rooted off the southwestern edge of the Strait of Gibraltar (Atlantic side) during the summer of 2000. The event is successfully simulated using high-resolution atmospheric and oceanic numerical models. It is shown that a sharp filament may develop oceanwards with little modification of the Atlantic inflow into the Mediterranean, contrary to usual expectations. The filament is essentially driven by the surface layer response to Gap winds occurring during Levanter conditions. The easterly wind funnelling in the Strait generates a strong wind jet and intense wind curl which impacts the oceanic surface layer through Ekman pumping and mixing processes. The generation and fate of the filament is very similar to the Gulf of Tehuantepec case, where strong Gap wind events produce asymmetric deformation and erosion of the thermocline that tends to favour anticyclonic mesoscale circulations. Our observations and model results from both realistic and idealized experiments suggest that similar phenomena are present in the Gulf of Cadiz, but they are altered by the persisting Atlantic inflow, so that the response to Gap winds is not as dramatic.

  20. Trace metals in surface sediments of the Taiwan Strait: geochemical characteristics and environmental indication.

    Science.gov (United States)

    Gao, Xuelu; Zhou, Fengxia; Lui, Hon-Kit; Lou, Jiann-Yuh; Chen, Chen-Tung Arthur; Zhuang, Wen

    2016-06-01

    The concentration and geochemical fractionation of six trace metals related with environmental quality assessment, namely Cd, Cr, Cu, Ni, Pb, and Zn, in 30 surface sediments from both inshore and offshore areas of the Taiwan Strait were measured to investigate their distribution characteristics, evaluate their potential mobility, and assess their pollution status. The geoaccumulation index results indicated that, on average, the studied metals presented an order of Cd > Pb > Ni > Zn > Cu > Cr and were practically in uncontaminated status except Cd. The results of the sequential extraction analysis indicated that, on average, the studied metals were mostly accumulated in residual fraction except Cd whose concentration was the highest in the acid soluble fraction presenting a high risk to the environment, and their mobility decreased in the sequence of Cd > Pb > Ni > Cu > Zn > Cr. Based on the mean probable effect level quotients, the combination of the studied metals had an 8 % probability of being toxic at two sampling sites and had a 21 % probability of being toxic at the rest of sites. The spatial distribution of the studied metals in total concentrations and different geochemical fractions corroborated the previous findings about the possible sediment transportation routes in and around the Taiwan Strait.

  1. PM10 retrieval over the water surface of Penang Straits from Landsat TM5 data

    Science.gov (United States)

    Lim, H. S.; MatJafri, M. Z.; Abdullah, K.; Saleh, N. Mohd.; Hashim, S. A.

    2007-04-01

    In this study, we used the Landsat TM data captured on 9 March 2006 for the retrieval of PM10 over the water surface of Penang Straits, Malaysia. PM10 measurements were collected using a handheld DustTrak TM meter simultaneously with the remotely sensed data acquisition. The PCI Geomatica version 9.1 digital image processing software was used in all image-processing analysis. An algorithm was developed based on the atmospheric optical characteristic. The digital numbers were extracted corresponding to the ground-truth locations for each band and then converted into radiance and reflectance values. The reflectance measured from the satellite [reflectance at the top of atmospheric, ρ(TOA)] was subtracted by the amount given by the surface reflectance to obtain the atmospheric reflectance. Then the atmospheric reflectance was related to the PM10 using regression analysis. These atmospheric reflectance values were used for calibration of the PM10 algorithm. The developed algorithm was used to correlate the digital signal and the PM10 concentration. The proposed algorithm produced a high correlation coefficient (R) and low root-mean-square error (RMS). The PM10 concentration was generated using this algorithm over the water surface of Penang straits.

  2. Linkages between atmospheric blocking, sea ice export through Fram Strait and the Atlantic Meridional Overturning Circulation

    Science.gov (United States)

    Ionita, M.; Scholz, P.; Lohmann, G.; Dima, M.; Prange, M.

    2016-09-01

    As a key persistent component of the atmospheric dynamics, the North Atlantic blocking activity has been linked to extreme climatic phenomena in the European sector. It has also been linked to Atlantic multidecadal ocean variability, but its potential links to rapid oceanic changes have not been investigated. Using a global ocean-sea ice model forced with atmospheric reanalysis data, here it is shown that the 1962–1966 period of enhanced blocking activity over Greenland resulted in anomalous sea ice accumulation in the Arctic and ended with a sea ice flush from the Arctic into the North Atlantic Ocean through Fram Strait. This event induced a significant decrease of Labrador Sea water surface salinity and an abrupt weakening of the Atlantic Meridional Overturning Circulation (AMOC) during the 1970s. These results have implications for the prediction of rapid AMOC changes and indicate that an important part of the atmosphere-ocean dynamics at mid- and high latitudes requires a proper representation of the Fram Strait sea ice transport and of the synoptic scale variability such as atmospheric blocking, which is a challenge for current coupled climate models.

  3. [The possible causes of the tragedy of "Port Famine" in the Strait of Magellan].

    Science.gov (United States)

    Espinoza G, Juan Pablo; Espinoza G, Ricardo

    2010-11-01

    The attempts to colonize the Strait of Magellan soon followed the discovery of this route. PeDro Sarmiento de Gamboa, a Spanish sailor, established human settlements to fortify those lands and control the transit of vessels, especially those of English corsairs, which devastated Chilean and Peruvian coasts. During the summer of 1584, approximately 500 soldiers, artisans, priests, women and children established two villages called "Nombre de Jesús" and "Rey Don Felipe". From the beginning, these settlers had leadership and communication problems and difficulties to obtain food. After three winters only 17 to 18 people survived according to the testimony of one of the survivors, that was rescued by an English sailor named Cavendish, which renamed the village "Rey Don Felipe" as "Port Famine". When he observed the scenes of abandonment and death, he supposed that the settlers died due to lack of food. Other factors that facilitated the desolation were hypothermia, execution, anthropophagy and lesions caused by natives. There is also a possibility that intoxication by red tide (harmful algal bloom) could explain in part the finding of unburied corpses in the strait beaches.

  4. Closing the Mass Budget between Bering Strait and the Arctic Basin: The Chukchi Slope Current

    Science.gov (United States)

    Corlett, W. B.; Pickart, R. S.

    2016-02-01

    After passing through Bering Strait, Pacific-origin water flows across the Chukchi Sea in different branches that ultimately exit the shelf and provide heat, freshwater, and nutrients to the interior basin. It is important, therefore, to understand where and by what mechanisms the water is fluxed offshore. We have compiled all known shipboard hydrographic sections occupied across the Chukchi shelfbreak and slope that include direct velocity measurements (shipboard ADCP or lowered ADCP). In all, there are 46 sections occupied during the months of May-October from 2002 to 2014, spanning the region from Barrow Canyon to approximately 168°W. The data reveal the presence of a surface-intensified, westward-flowing current over the continental slope, situated offshore of the eastward-flowing shelfbreak jet. We call this feature the Chukchi slope current, which exists under all wind conditions. Using these data plus previously published transport values in Bering Strait and the Beaufort shelfbreak jet, we attempt to close the mass budget of the Chukchi shelf. The mean heat transport of the Chukchi slope current during the summer months is estimated, which has the potential to melt a substantial amount of pack-ice in the Canada Basin and influence the geographical distribution of the ice melt.

  5. Genome and transcriptome analysis of the basidiomycetous yeast Pseudozyma antarctica producing extracellular glycolipids, mannosylerythritol lipids.

    Directory of Open Access Journals (Sweden)

    Tomotake Morita

    Full Text Available Pseudozyma antarctica is a non-pathogenic phyllosphere yeast known as an excellent producer of mannosylerythritol lipids (MELs, multi-functional extracellular glycolipids, from vegetable oils. To clarify the genetic characteristics of P. antarctica, we analyzed the 18 Mb genome of P. antarctica T-34. On the basis of KOG analysis, the number of genes (219 genes categorized into lipid transport and metabolism classification in P. antarctica was one and a half times larger than that of yeast Saccharomyces cerevisiae (140 genes. The gene encoding an ATP/citrate lyase (ACL related to acetyl-CoA synthesis conserved in oleaginous strains was found in P. antarctica genome: the single ACL gene possesses the four domains identical to that of the human gene, whereas the other oleaginous ascomycetous species have the two genes covering the four domains. P. antarctica genome exhibited a remarkable degree of synteny to U. maydis genome, however, the comparison of the gene expression profiles under the culture on the two carbon sources, glucose and soybean oil, by the DNA microarray method revealed that transcriptomes between the two species were significantly different. In P. antarctica, expression of the gene sets relating fatty acid metabolism were markedly up-regulated under the oily conditions compared with glucose. Additionally, MEL biosynthesis cluster of P. antarctica was highly expressed regardless of the carbon source as compared to U. maydis. These results strongly indicate that P. antarctica has an oleaginous nature which is relevant to its non-pathogenic and MEL-overproducing characteristics. The analysis and dataset contribute to stimulate the development of improved strains with customized properties for high yield production of functional bio-based materials.

  6. Physical oceanographic mooring data (temperature, salinity, velocity including ADCP ice tracking) collected from Bering Strait Moorings A2,A4, A3 in Bering Strait from 2013-07-05 to 2014-07-02 (NCEI Accession 0156230)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This is an archive of data from moorings deployed in Bering Strait from summer 2013 to summer 2014. Mooring deployments were funded by the ONR award N00014-13-1-0468...

  7. Vertical Temperature Simulation of Pegasus Runway, McMurdo Station, Antarctica

    Science.gov (United States)

    2015-01-01

    Runway, McMurdo Station, Antarctica Co ld R eg io ns R es ea rc h an d En gi ne er in g La bo ra to ry Steven F. Daly, Robert Haehnel...Vertical Temperature Simulation of Pegasus Runway, McMurdo Station, Antarctica Steven F. Daly, Robert Haehnel, and Christopher Hiemstra Cold Regions...Engineering Support, Continuation” ERDC/CRREL TR-15-2 ii Abstract Pegasus Runway, located 13 km south of McMurdo Station, Antarctica , on the

  8. Dioszegia antarctica sp. nov. and Dioszegia cryoxerica sp. nov., psychrophilic basidiomycetous yeasts from polar desert soils in Antarctica

    Science.gov (United States)

    Rodriguez, Russell J.; Connell, L.; Redman, R.; Barrett, A.; Iszard, M.; Fonseca, A.

    2010-01-01

    During a survey of the culturable soil fungal population in samples collected in Taylor Valley, South Victoria Land, Antarctica, 13 basidiomycetous yeast strains with orange-coloured colonies were isolated. Phylogenetic analyses of internal transcribed spacer (ITS) and partial LSU rRNA gene sequences showed that the strains belong to the Dioszegia clade of the Tremellales (Tremellomycetes, Agaricomycotina), but did not correspond to any of the hitherto recognized species. Two novel species, Dioszegia antarctica sp. nov. (type strain ANT-03-116T =CBS 10920T =PYCC 5970T) and Dioszegia cryoxerica sp. nov. (type strain ANT-03-071T =CBS 10919T =PYCC 5967T), are described to accommodate ten and three of these strains, respectively. Analysis of ITS sequences demonstrated intrastrain sequence heterogeneity in D. cryoxerica. The latter species is also notable for producing true hyphae with clamp connections and haustoria. However, no sexual structures were observed. The two novel species can be considered obligate psychrophiles, since they failed to grow above 20 °C and grew best between 10 and 15 °C.

  9. Mobile Devices for Tertiary Study--Philosophy Meets Pragmatics for Remote Aboriginal and Torres Strait Islander Women

    Science.gov (United States)

    Townsend, Philip

    2015-01-01

    This paper outlines PhD research which suggests mobile learning fits the cultural philosophies and roles of Aboriginal and Torres Strait Islander women who are preservice teachers in the very remote Australian communities where the research was conducted. The problem which the research addresses is the low completion rates for two community-based…

  10. The Fallacy of the Bolted Horse: Changing Our Thinking about Mature-Age Aboriginal and Torres Strait Islander University Students

    Science.gov (United States)

    Plater, Suzanne; Mooney-Somers, Julie; Lander, Jo

    2015-01-01

    The aim of this article is to critically review and analyse the public representations of mature-age university students in developed and some developing nations and how they compare to the public representations of mature-age Aboriginal and Torres Strait Islander university students in Australia ("students" also refers to graduates…

  11. Residual flow and tidal asymmetry in the Singapore Strait, with implications for resuspension and residual transport of sediment

    NARCIS (Netherlands)

    Van Maren, D.S.; Gerritsen, H.

    2012-01-01

    The Singapore Strait connects the South China Sea, where tides are dominantly diurnal, to the dominantly semidiurnal Indian Ocean. At this transition, the tidal water level oscillations are observed to be semidiurnal while the tidal current oscillations are mixed, diurnal to fully diurnal. Due to

  12. The 1908 Messina Earthquake and the Messina Straits Seismicity as Shallow Expression of Wide Depth-Range Regional Geodynamic Processes

    Science.gov (United States)

    Neri, G.; Orecchio, B.; Presti, D.

    2008-12-01

    New tomographic results in the Calabro-Peloritan Arc region show that the Messina Straits area delineates the transition between the only sector where the Ionian slab is in-depth continuous and therefore still capable to retreat (Southern Calabria) and the south-western boundary of the subduction system now interested by continental collision (central-western Sicily). This geodynamic framework produces the seismogenic stress field detected in the Straits crustal structure, characterised by ESE-oriented extension and by minor strike- slip component. Stress field and seismicity analyses performed in the area reveal that the 1908 earthquake source is characterised by normal faulting, is located in the Straits and it strikes about NNE-SSW with the top below Sicilian shoreline and dip toward east. Also, in spite of the very low seismicity levels recorded since the installation of local seismic network (late '70s), the analysis performed on historical catalogue data (CPTI, http://emidius.mi.ingv.it/CPTI/) for the period 1780-2002 highlights that the Messina Straits is one of the most active areas in Italy, also excluding phases of maximum destructive capability.

  13. Hearing the Voice of Remote Aboriginal and Torres Strait Islander Training Stakeholders Using Research Methodologies and Theoretical Frames of Reference

    Science.gov (United States)

    Guenther, John; Osborne, Sam; Arnott, Allan; McRae-Williams, Eva

    2017-01-01

    Researchers in remote Aboriginal and Torres Strait Islander contexts within Australia are frequently faced with the challenges of working in an intercultural space where channels of communication are garbled with interference created by the complexities of misunderstood worldviews, languages, values and expectations. A concern of many researchers…

  14. Liquid freshwater transport estimates from the East Greenland Current based on continuous measurements north of Denmark Strait

    NARCIS (Netherlands)

    de Steur, L.; Pickart, R.S.; Macrander, A.; Våge, K.; Harden, B.; Jónsson, S.; Østerhus, S.; Valdimarsson, H.

    2017-01-01

    Liquid freshwater transports of the shelfbreak East Greenland Current (EGC) and the separated EGC are determined from mooring records from the Kögur section north of Denmark Strait between August 2011 and July 2012. The 11 month mean freshwater transport (FWT), relative to a salinity of 34.8, was 65

  15. Modeling Evaluation of Tidal Stream Energy and the Impacts of Energy Extraction on Hydrodynamics in the Taiwan Strait

    Directory of Open Access Journals (Sweden)

    Ming-Hsi Hsu

    2013-04-01

    Full Text Available Tidal stream speeds in straits are accelerated because of geographic and bathymetric features. For instance, narrow channels and shallows can cause high tidal stream energy. In this study, water level and tidal current were simulated using a three-dimensional semi-implicit Eulerian-Lagrangian finite-element model to investigate the complex tidal characteristics in the Taiwan Strait and to determine potential locations for harnessing tidal stream energy. The model was driven by nine tidal components (M2, S2, N2, K2, K1, O1, P1, Q1, and M4 at open boundaries. The modeling results were validated with the measured data, including water level and tidal current. Through the model simulations, we found that the highest tidal currents occurred at the Penghu Channel in the Taiwan Strait. The Penghu Channel is an appropriate location for the deployment of a tidal turbine array because of its deep and flat bathymetry. The impacts of energy extraction on hydrodynamics were assessed by considering the momentum sink approach. The simulated results indicate that only minimal impacts would occur on water level and tidal current in the Taiwan Strait if a turbine array (55 turbines was installed in the Penghu Channel.

  16. New Approaches to Cross-Strait Integration and Its Impacts on Taiwan’s Domestic Economy: An Emerging “Chaiwan”?

    Directory of Open Access Journals (Sweden)

    Gordon C. K. Cheung

    2010-04-01

    Full Text Available Taiwan’s Legislative Yuan and Presidential elections in January and March 2008 respectively re-orientated cross-Strait relations from hostility to co-operation. On 4 November 2008, Chen Yunlin, head of the Association for Relations Across the Taiwan Straits (ARATS, and Chiang Pin-kun (Jiang Bingkun, chairman of Taiwan’s Straits Exchange Foundation (SEF, meeting in the Second Chiang-Chen Talks in Taiwan, took a historical step in the further development of cross-Strait relations. Agreements were signed on direct air and sea transport, postal services and food-safety security. On 22 December 2009, the Fourth Chiang- Chen Talks took place in Taizhong and more substantial and technical agreements were signed on agriculture, inspection/ accreditation and fisheries. It seems that continuous integration between China and Taiwan is inevitable. To address the implications of this process for Taiwan’s domestic economy, four dimensions of the current cross-Strait relationship are scrutinized: guanxi, plutocracy, legalism and the idea of a Chinese Common Market. It is argued that in order to intensify economic co-operation across the Taiwan Strait, more institutionalization of the cross-Strait relationship must be brought about.

  17. Environmental and climate changes in Antarctica in the Geological Past

    Directory of Open Access Journals (Sweden)

    G. L. Leitchenkov

    2014-01-01

    Full Text Available In the Cretaceous time, Antarctica was characterized by subtropical and tropical climate. The Early Eocene was warmest in the Antarctic history but this Climatic Optimum terminated with a long-term cooling trend that culminated in continental-scale glaciation of Antarctica at about 34 Ma ago. There is indirect evidence that small ice caps developed within central Antarctica in the Late Eocene (42−34 Ma. From the Early Oligocene to the Middle Miocene (34−13 Ma ice sheet was wet-based and fluctuated considerably in volume, but about 14 m.y. ago it became dry-based and more stable.  Seismic data collected on the East Antarctic margin give valuable information on dynamics of the past ice sheets. These data shows that the sedimentary cover of the western Wilkes Land margin includes a giant (c. 200 000 km2 deep-water fan which formed between c. 43 and 34 Ma ago. The average rate of sedimentation in the central part of fan was 230–250 m/m.y. Active input of terrigenous sediments into deep-water denotes high-energy fluvial system within the Wilkes Land. Emergence of this fluvial system evidences earliest glaciation in the Antarctic interior which fed full-flowing rivers. The thickness of strata deposited during post-Early Oligocene glaciations on the Antarctic margin generally reflects the averaged energy of depositional environments. The thickest sediments (up to 2.0 km, i.e. almost twice more than in other parts of East Antarctic margin and inferred highest energy are seen in the central Cooperation Sea, on the central Wilkes Land margin and in the D'Urville Sea. The areas with the thickest post-Early Oligocene strata correlate with places where present-day ice discharge is highest, such as via the Lambert, Totten and Mertz/Ninnis Glaciers. The correlation points to high ice (and sediment flux in the same areas since the Early Oligocene.

  18. Crustal structure across the Filchner Ronne Shelf, Antarctica

    Science.gov (United States)

    Herter, U.; Jokat, W.

    2012-04-01

    Crustal structure across the Filchner Ronne Shelf, Antarctica U. Herter, W. Jokat One large gap in understanding the tectonic evolution of Antarctica beside the few rock outcrops on the continent is the missing information on crustal thickness along its margins but also in its interior. E.g., the few marine deep seismic lines are located mainly along the Antarctic Peninsula/Pacific margin, but for most of the East Antarctic margins such information is not available. In this contribution we concentrate on one of the most remote areas in Antarctica, the Filchner Ronne Shelf (FRS). The area is underlain by approximately 12 km of sediments, but its crustal fabric is questionable. Thus, some existing deep seismic sounding data were modeled and reinterpreted. Especially, data gathered in 1995 have been analyzed, and a more detailed 2D P-wave velocity model has been calculated. For the profiles in total 12 RefTek stations each with nine geophone chains were placed on the ice shelf and 3175 airgun shots along a 480 km transect were fired by two 32 l BOLT-Airguns each 60 s. Signals were recorded up to distances of 180 km. Due to the ice coverage it was not possible to acquire the data without gaps or along straight lines, which caused some difficulties in the modeling process. Furthermore, in the new model all data from older experiments of the AWI and Soviet Antarctic expeditions acquired with dynamite sources were incorporated. The model shows a sedimentary basin with a thickness up to 12 km and a large velocity inversion in a deeper sediment unit. The crustal thickness varies from 40 km beneath the Antarctic Peninsula, and 14 km of basement in the center part of the profile. Towards Berkner Island the crust thickens again, but the top of the basement is still 11 km deep. The lower crustal velocities range between 6.8 and 7.2 km/s. We interpret the crustal structure as clear evidence for the presence of a failed rift. The initial stretching of the continental crust

  19. Anaerobic psychrophiles from Lake Zub and Lake Untersee, Antarctica

    Science.gov (United States)

    Townsend, Alisa; Pikuta, Elena V.; Guisler, Melissa; Stahl, Sarah; Hoover, Richard B.

    2009-08-01

    The study of samples from Antarctica 2008 and 2009 expeditions organized and successfully conducted by Richard Hoover led to the isolation of diverse anaerobic strains with psychrotolerant and psychrophilic physiology. Due to the fact that Lake Untersee has never been subject to microbiological study, this work with the samples has significant and pioneering impact to the knowledge about the biology of this unique ecosystem. Also, the astrobiological significance for the study of these ecosystems is based on new findings of ice covered water systems on other bodies of our solar system. Anaerobic psychrotolerant strain LZ-22 was isolated from a frozen sample of green moss with soils around the rhizosphere collected near Lake Zub in Antarctica. Morphology of strain LZ-22 was observed to be motile, rod shaped and spore-forming cells with sizes 1 x 5-10 μm. This new isolate is a mesophile with the maximum temperature of growth at 40°C. Strain LZ-22 is able to live on media without NaCl and in media with up to 7 % (w/v) NaCl. It is catalase negative and grows only on sugars with the best growth rate being on lactose. The strain is a neutrophile and grows between pH 5 and 9.0 with the optimum at 7.8. Another two strains UL7-96mG and LU-96m7P were isolated from deep water samples of Lake Untersee. Proteolytic strain LU-96m7P had a truly psychrophilic nature and refused to grow at room temperature. Sugarlytic strain UL7-96mG was found to be psychrotolerant, but its rate of growth at 3°C was very high compared with other mesophiles. Two homoacetogenic psychrophilic strains A7AC-96m and AC-DS7 were isolated and purified from samples of Lake Untersee; both of them are able to grow chemolithotrophically on H2+CO2. In the presence of lactate, these strains are able to grow only at 0-18 °C, and growth at 22 °C was observed only with yeast extract stimulation. In this paper, physiological and morphological characteristics of novel psychrophilic and psychrotolerant isolates

  20. Antarctica, supercontinents and the palaeogeography of the Cambrian 'explosion'

    Science.gov (United States)

    Dalziel, Ian

    2014-05-01

    Laurentia is bordered by latest Precambrian-Cambrian rifted margins and must therefore have been located within a Precambrian supercontinent. Geochronologic and geochemical evidence indicates that it was attached to parts of the East Antarctic craton within the Rodinian supercontinent in the late Mesoproterozoic. The Mawson craton of Antarctica rifted from the proto-Pacific margin of Laurentia during the Neooproterozoic, colliding with the present 'southern cone' of Laurentia at ~600 Ma along the Shackleton Range suture zone as Gondwana and Laurentia amalgamated to form the ephemeral Pannotia supercontinental assembly at the end of the Precambrian. The abrupt appearance of almost all animal phyla in the fossil record is often colloquially referred to as the Cambrian 'explosion' of life on Earth. It is also named 'Darwin's dilemma,' as he appreciated that this seemingly mysterious event posed a major problem for his theory of evolution by natural selection. It coincided with a time of major marine transgression over all the continents. Although the metazoan 'explosion' is now seen as more protracted than formerly recognized, it is still regarded one of the most critical events in the history of the biosphere. One of the most striking aspects of the earliest Cambrian fossils is geographic differentiation. In particular, the first benthic trilobite faunas on Laurentia, ancestral North America, and the newly amalgamated southern supercontinent of Gondwana are distinctly different. This has led to the suggestion of an unknown vicariant event intervening between an ancestral trilobite clade and higher members that are represented in the fossil record, possibly one related to the breakup of a supercontinent. Igneous rocks along the Panthalassic margin of Gondwana, including South America, southernmost Africa and the Ellsworth-Whitmore crustal block of Antarctica, and along the proto-Appalachian margin of Laurentia indicate that final separation of Laurentia from

  1. New Views of East Antarctica- from Columbia to Gondwana

    Science.gov (United States)

    Ferraccioli, F.; Forsberg, R.; Aitken, A.; Young, D. A.; Blankenship, D. D.; Bell, R. E.; Finn, C.; Martos, Y. M.; Armadillo, E.; Jacobs, J.; Ebbing, J.; Eagles, G.; Jokat, W.; Jordan, T. A.; Ruppel, A.; Läufer, A.; Dalziel, I. W. D.

    2015-12-01

    East Antarctica is a keystone in the Gondwana, Rodinia and the Columbia supercontinents. Recent aerogeophysical research, augmented by satellite magnetic, gravity and seismological data is unveiling the crustal architecture of the continent. This is helping comprehend the impact of supercontinental processes such as subduction, accretion, rifting and intraplate tectonics on its evolution. A mosaic of Precambrian basement provinces is apparent in interior East Antarctica (Ferraccioli et al., 2011, Nature). A major suture separates the Archean-Neoproterozoic Ruker Province from an inferred Grenvillian-age orogenic Gamburtsev Province with remarkably thick crust (up to 60 km thick) and thick lithosphere (over 200 km thick). The age of the suturing and its linkages with supercontinental assembly is debated with both Rodinia and Gondwana candidates being proposed. Further east, magnetic highs delineate a Paleo to Mesoproterozoic Nimrod-South Pole igneous province (Goodge and Finn, 2010 JGR) that flanks a composite Mawson Continent- including the Gawler Craton of South Australia (Aitken et al., 2014 GRL). An over 1,900 km long magnetic and gravity lineament is imaged along the western flank of the Wilkes Subglacial Basin and is interpreted here as a major Paleoproterozoic suture zone linked to the collision of Laurentia and East Antarctica within Columbia. The proposed suture played a pivotal role helping localise Neoproterozoic Rodinia rifted margin evolution and forming a backstop for the Ross-Delamerian cycle of Gondwana amalgamation. Aeromagnetic and gravity imaging help determine the extent of a Keweenawan-age (ca 1.1 Ga) large igneous province in the Coats Land Block -isotopically tied with the Mid-Continent Rift System of Laurentia (Loewy et al., 2011 Geology). Imprints of Grenvillian magmatic arc accretion link together the Namaqua-Natal and Maud belts in South Africa and Dronning Maud Land within Rodinia. The aeromagnetically distinct Southeast Dronning Maud

  2. Anaerobic Psychrophiles from Lake Zub and Lake Untersee, Antarctica

    Science.gov (United States)

    Townsend, Alisa; Pikuta, Elena V.; Guisler, Melissa; Stahl, Sarah; Hoover, Richard B.

    2009-01-01

    The study of samples from Antarctica 2008 and 2009 expeditions organized and successfully conducted by Richard Hoover led to the isolation of diverse anaerobic strains with psychrotolerant and psychrophilic physiology. Due to the fact that Lake Untersee has never been subject to microbiological study, this work with the samples has significant and pioneering impact to the knowledge about the biology of this unique ecosystem. Also, the astrobiological significance for the study of these ecosystems is based on new findings of ice covered water systems on other bodies of our solar system. Anaerobic psychrotolerant strain LZ-22 was isolated from a frozen sample of green moss with soils around the rhizosphere collected near Lake Zub in Antarctica. Morphology of strain LZ-22 was observed to be motile, rod shaped and spore-forming cells with sizes 1 x 5-10 micron. This new isolate is a mesophile with the maximum temperature of growth at 40C. Strain LZ-22 is able to live on media without NaCl and in media with up to 7% (w/v) NaCl. It is catalase negative and grows only on sugars with the best growth rate being on lactose. The strain is a neutrophile and grows between pH 5 and 9.0 with the optimum at 7.8. Another two strains UL7-96mG and LU-96m7P were isolated from deep water samples of Lake Untersee. Proteolytic strain LU-96m7P had a truly psychrophilic nature and refused to grow at room temperature. Sugarlytic strain UL7-96mG was found to be psychrotolerant, but its rate of growth at 3C was very high compared with other mesophiles. Two homoacetogenic psychrophilic strains A7AC-96m and AC-DS7 were isolated and purified from samples of Lake Untersee; both of them are able to grow chemolithotrophically on H2+CO2. In the presence of lactate, these strains are able to grow only at 0-18C, and growth at 22C was observed only with yeast extract stimulation. In this paper, physiological and morphological characteristics of novel psychrophilic and psychrotolerant isolates from

  3. Distributions of larval and juvenile/adult stages of the Antarctic myctophid fish, Electrona antarctica, off Wilkes Land in East Antarctica

    Science.gov (United States)

    Moteki, Masato; Fujii, Kentaro; Amakasu, Kazuo; Shimada, Keishi; Tanimura, Atsushi; Odate, Tsuneo

    2017-06-01

    Myctophid fish are an important component of the Southern Ocean food web because of their very high biomass. This study investigated the spatial distributions of larval and juvenile/adult stages of the Antarctic myctophid Electrona antarctica. Fish were sampled in January 2011 and 2012 on a transect along 140°E and in January 2013 along 110°E using two different opening/closing net systems. In total, 1075 specimens of E. antarctica were collected: 948 larvae, 127 juveniles/adults, and 2 in the transformation stage. Most larvae were collected at 5-200 m depth, with diel vertical migration (DVM) not apparent. Larvae were mainly distributed in the Modified Circumpolar Deep Water (-1.5 °C-2.0 °C). By contrast, an analysis of the echogram at 38 kHz and discrete depth samples implied that juveniles/adults undertook DVM except in the continental slope area (65.5°S). As the distribution of krill is limited to the cold water mass (<-1.5 °C) along the continental slope, E. antarctica and krill populations are spatially separated off Wilkes Land during summer. According to the previously estimated larval period of 30-47 days, E. antarctica may spawn in late November to December in the marginal ice zone or near the sea ice edge. This study suggests that the environment related to sea ice provides a nursery ground for early stage larvae of E. antarctica.

  4. Splitting of Atlantic water transport towards the Arctic Ocean into the Fram Strait and Barents Sea Branches - mechanisms and consequences

    Science.gov (United States)

    Beszczynska-Möller, Agnieszka; Skagseth, Øystein; von Appen, Wilken-Jon; Walczowski, Waldemar; Lien, Vidar

    2016-04-01

    The heat content in the Arctic Ocean is to a large extent determined by oceanic advection from the south. During the last two decades the extraordinary warm Atlantic water (AW) inflow has been reported to progress through the Nordic Seas into the Arctic Ocean. Warm anomalies can result from higher air temperatures (smaller heat loss) in the Nordic Seas, and/or from an increased oceanic advection. But the ultimate fate of warm anomalies of Atlantic origin depends strongly on their two possible pathways towards the Arctic Ocean. The AW temperature changes from 7-10°C at the entrance to the Nordic Seas, to 6-6.5°C in the Barents Sea opening and 3-3.5°C as the AW leaving Fram Strait enters the Arctic Ocean. When AW passes through the shallow Barents Sea, nearly all its heat is lost due to atmospheric cooling and AW looses its signature. In the deep Fram Strait the upper part of Atlantic water becomes transformed into a less saline and colder surface layer and thus AW preserves its warm core. A significant warming and high variability of AW volume transport was observed in two recent decades in the West Spitsbergen Current, representing the Fram Strait Branch of Atlantic inflow. The AW inflow through Fram Strait carries between 26 and 50 TW of heat into the Arctic Ocean. While the oceanic heat influx to the Barents Sea is of a similar order, the heat leaving it through the northern exit into the Arctic Ocean is negligible. The relative strength of two Atlantic water branches through Fram Strait and the Barents Sea governs the oceanic heat transport into the Arctic Ocean. According to recently proposed mechanism, the Atlantic water flow in the Barents Sea Branch is controlled by the strength of atmospheric low over the northern Barents Sea, acting through a wind-induced Ekman divergence, which intensifies eastward AW flow. The Atlantic water transport in the Fram Strait Branch is mainly forced by the large-scale low-pressure system over the eastern Norwegian and

  5. Assessment of circulation and inter-basin transport in the Salish Sea including Johnstone Strait and Discovery Islands pathways

    Science.gov (United States)

    Khangaonkar, Tarang; Long, Wen; Xu, Wenwei

    2017-01-01

    The Salish Sea consisting of Puget Sound and Georgia Basin in U.S and Canadian waters has been the subject of several independent data collection and modeling studies. However, these interconnected basins and their hydrodynamic interactions have not received attention as a contiguous unit. The Strait of Juan de Fuca is the primary pathway through which Pacific Ocean water enters the Salish Sea but the role played by Johnstone Strait and the complex channels northeast of Vancouver Island, connecting the Salish Sea and the Pacific Ocean, on overall Salish Sea circulation has not been characterized. In this paper we present a modeling-based assessment of the two-layer circulation and transport through the multiple interconnected sub-basins within the Salish Sea including the effect of exchange via Johnstone Strait and Discovery Islands. The Salish Sea Model previously developed using the finite volume community ocean model (FVCOM) was expanded over the continental shelf for this assessment encircling Vancouver Island, including Discovery Islands, Johnstone Strait, Broughton Archipelago and the associated waterways. A computational technique was developed to allow summation of volume fluxes across arbitrary transects through unstructured finite volume cells. Tidally averaged volume fluxes were computed at multiple transects. The results were used to validate the classic model of Circulation in Embracing Sills for Puget Sound and to provide quantitative estimates of the lateral distribution of tidally averaged transport through the system. Sensitivity tests with and without exchanges through Johnstone Strait demonstrate that it is a pathway for Georgia Basin runoff and Fraser River water to exit the Salish Sea and for Pacific Ocean inflow. However the relative impact of this exchange on circulation and flushing in Puget Sound Basin is small.

  6. Assessment of circulation and inter-basin transport in the Salish Sea including Johnstone Strait and Discovery Islands pathways

    Energy Technology Data Exchange (ETDEWEB)

    Khangaonkar, Tarang; Long, Wen; Xu, Wenwei

    2017-01-01

    The Salish Sea consisting of Puget Sound and Georgia Basin in U.S and Canadian waters has been the subject of several independent data collection and modeling studies. However, these interconnected basins and their hydrodynamic interactions have not received attention as a contiguous unit. The Strait of Juan de Fuca is the primary pathway through which Pacific Ocean water enters the Salish Sea but the role played by Johnstone Strait and the complex channels northeast of Vancouver Island, connecting the Salish Sea and the Pacific Ocean, on overall Salish Sea circulation has not been characterized. In this paper we present a modeling-based assessment of the two-layer circulation and transport through the multiple interconnected sub-basins within the Salish Sea including the effect of exchange via Johnstone Strait and Discovery Islands. The Salish Sea Model previously developed using the finite volume community ocean model (FVCOM) was expanded over the continental shelf for this assessment encircling Vancouver Island, including Discovery Islands, Johnstone Strait, Broughton Archipelago and the associated waterways. A computational technique was developed to allow summation of volume fluxes across arbitrary transects through unstructured finite volume cells. Tidally averaged volume fluxes were computed at multiple transects. The results were used to validate the classic model of Circulation in Embracing Sills for Puget Sound and to provide quantitative estimates of the lateral distribution of tidally averaged transport through the system. Sensitivity tests with and without exchanges through Johnstone Strait demonstrate that it is a pathway for Georgia Basin runoff and Fraser River water to exit the Salish Sea and for Pacific Ocean inflow. However the relative impact of this exchange on circulation and flushing in Puget Sound Basin is small.

  7. Measuring emotional and social wellbeing in Aboriginal and Torres Strait Islander populations: an analysis of a Negative Life Events Scale

    Directory of Open Access Journals (Sweden)

    Gunthorpe Wendy

    2007-11-01

    Full Text Available Abstract Aboriginal and Torres Strait Islander Australians experience widespread socioeconomic disadvantage and health inequality. In an attempt to make Indigenous health research more culturally-appropriate, Aboriginal and Torres Strait Islander Australians have called for more attention to the concept of emotional and social wellbeing (ESWB. Although it has been widely recognised that ESWB is of crucial importance to the health of Aboriginal and Torres Strait Islander peoples, there is little consensus on how to measure in Indigenous populations, hampering efforts to better understand and improve the psychosocial determinants of health. This paper explores the policy and political context to this situation, and suggests ways to move forward. The second part of the paper explores how scales can be evaluated in a health research setting, including assessments of endorsement, discrimination, internal and external reliability. We then evaluate the use of a measure of stressful life events, the Negative Life Events Scale (NLES, in two samples of Aboriginal people living in remote communities in the Northern Territory of Australia. We argue that the Negative Life Events Scale is a promising assessment of psychosocial wellbeing in Aboriginal and Torres Strait Islander populations. Evaluation of the scale and its performance in other samples of Aboriginal and Torres Strait Islander populations is imperative if we hope to develop better, rather than more, scales for measuring ESWB among Indigenous Australians. Only then will it be possible to establish standardized methods of measuring ESWB and develop a body of comparable literature that can guide both a better understanding of ESWB, and evaluation of interventions designed to improve the psychosocial health of Indigenous populations and decrease health inequalities.

  8. Aboriginal and Torres Strait Islander Worldviews and Cultural Safety Transforming Sexual Assault Service Provision for Children and Young People

    Directory of Open Access Journals (Sweden)

    Leticia Funston

    2013-08-01

    Full Text Available Child Sexual Assault (CSA in Aboriginal and Torres Strait Islander communities is a complex issue that cannot be understood in isolation from the ongoing impacts of colonial invasion, genocide, assimilation, institutionalised racism and severe socio-economic deprivation. Service responses to CSA are often experienced as racist, culturally, financially and/or geographically inaccessible. A two-day forum, National Yarn Up: Sharing the Wisdoms and Challenges of Young People and Sexual Abuse, was convened by sexual assault services to identify the main practice and policy concerns regarding working with Aboriginal and Torres Strait Islander children and young people (C&YP, families and communities in the context of CSA. The forum also aimed to explore how services can become more accountable and better engaged with the communities they are designed to support. The forum was attended by eighty invited Aboriginal and Torres Strait Islander and non-Aboriginal youth sexual assault managers and workers representing both “victim” and “those who sexually harm others” services. In keeping with Aboriginal Community-Based Research methods forum participants largely directed discussions and contributed to the analysis of key themes and recommendations reported in this article. The need for sexual assault services to prioritise cultural safety by meaningfully integrating Aboriginal and Torres Strait Islander Worldviews emerged as a key recommendation. It was also identified that collaboration between “victims” and “those who sexually harm” services are essential given Aboriginal and Torres Strait Islander C&YP who sexually harm others may have also been victims of sexual assault or physical violence and intergenerational trauma. By working with the whole family and community, a collaborative approach is more likely than the current service model to develop cultural safety and thus increase the accessibility of sexual assault services.

  9. Isotopic and geochemical signatures of Late Quaternary sediments in the Fram Strait area

    Science.gov (United States)

    Maccali, J.; Hillaire-Marcel, C.; Carignan, J.; Reisberg, L. C.

    2010-12-01

    Arctic freshwater/sea-ice export through Fram Strait contributes to the Atlantic Meridional Overturning Circulation (AMOC) and acts as a trigger or feedback mechanism in the climate/ocean system. Here, geochemical and isotopic analyses of cores raised along a transect through the Strait are used to document changes in sediment sources and sea-ice transport since the LGM. Radiogenic isotope and elemental data in leachable fractions vs residues are used as proxies for water mass vs sediment source signatures, respectively. Unequivocal linkage between leachates and water-mass properties are illustrated by the anthropogenic-lead overprint in leachates from core-top sediments. Below this polluted layer, leachates and residues from late Holocene sediments carry distinct geochemical signatures E and W of the Strait. Eastward, below the North Atlantic Water (NAW) mass flowing northward, Th/Zr and Th/Pb concentration ratios ranging 0.040-0.041 and 0.85-0.90, respectively, label GIN seas and western Spitzbergen sediment-sources. Westward, below outflowing Arctic waters and sea-ice routes, these ratios range 0.032-0.035 and 0.72-0.75, respectively, and label NE Greenland and Arctic sediment sources. Pb-isotopes exhibit a similar pattern with sediment carrying a mixed Variscan-Pan-African signature below the NAW route, and a mixture of less radiogenic sources in sediments deposited below the outflowing Arctic waters and sea-ice route. Back in time, divergent trends in some radiogenic isotope values are recorded westward, below the outflowing Arctic waters and sea-ice route. Whereas isotopic properties of residues suggest sedimentary supplies originating from the Canadian Arctic and/or the NW Greenland margin, lead data from leachates bear an "Arctic Ocean" signature illustrating variable relative contributions from the Russian vs Canadian ice-margins and/or rivers. During deglacial times, a significant change in sedimentary supplies is recorded at ~ 14 ka along with some

  10. Physical characteristic of brown algae (Phaeophyta from madura strait as irreversible hydrocolloid impression material

    Directory of Open Access Journals (Sweden)

    Prihartini Widiyanti

    2012-09-01

    Full Text Available Background: Brown algae is a raw material for producing natrium alginates. One type of brown algae is Sargassum sp, a member of Phaeophyta division. Sargassum sp could be found in Madura strait Indonesia. Natrium alginate can be extracted from Sargassum sp. The demand of alginate in Indonesia is mainly fulfilled from abroad, meanwhile Sargassum sp is abundantly available. Purpose: The purpose of study were to explore the potency of brown alga Sargassum sp from Madura strait as hydrocolloid impression material and to examine its physical characteristic. Methods: The methods of research including extraction natrium alginate from Sargassum sp, synthesis of dental impression material and the test of porosity, density, viscosity, and water content of impression material which fulfilled the standard of material used in clinical application in dentistry. Results: Extraction result of Sargassum sp was natrium alginate powder with cream colour, odorless, and water soluble. The water content of natrium alginate was 21.64% and the viscosity was 0.7 cPs. The best porosity result in the sample with the addition of trinatrium phosphate 4% was 3.61%. Density value of impression material was 3 gr/cm3. Conclusion: The research suggested that brown algae Sargassum sp from Madura strait is potential as hydrocolloid impression material, due to its physical properties which close to dental impression material, but still need further research to optimize the physical characteristic.Latar belakang: Alga coklat adalah sumber bahan baku material natrium alginat. Salah satu jenis alga coklat adalah Sargassum sp yang merupakan anggota divisi Phaeophyta. Sargassum sp dapat ditemukan di Selat Madura Indonesia. Natrium alginat dapat diekstraksi dari Sargassum sp. Kebutuhan akan bahan ini di Indonesia sebagian besar dipenuhi dari impor, padahal ketersediaan Sargassum sp di Indonesia sangat melimpah. Tujuan: Penelitian ini bertujuan untuk mengeksplorasi potensi alga coklat

  11. Upper-crustal structure beneath the strait of Georgia, Southwest British Columbia

    Science.gov (United States)

    Dash, R.K.; Spence, G.D.; Riedel, M.; Hyndman, R.D.; Brocher, T.M.

    2007-01-01

    We present a new three-dimensional (3-D) P-wave velocity model for the upper-crustal structure beneath the Strait of Georgia, southwestern British Columbia based on non-linear tomographic inversion of wide-angle seismic refraction data. Our study, part of the Georgia Basin Geohazards Initiative (GBGI) is primarily aimed at mapping the depth of the Cenozoic sedimentary basin and delineating the near-surface crustal faults associated with recent seismic activities (e.g. M = 4.6 in 1997 and M = 5.0 in 1975) in the region. Joint inversion of first-arrival traveltimes from the 1998 Seismic Hazards Investigation in Puget Sound (SHIPS) and the 2002 Georgia Basin experiment provides a high-resolution velocity model of the subsurface to a depth of ???7 km. In the southcentral Georgia Basin, sedimentary rocks of the Cretaceous Nanaimo Group and early Tertiary rocks have seismic velocities between 3.0 and 5.5 km s-1. The basin thickness increases from north to south with a maximum thickness of 7 (??1) km (depth to velocities of 5.5 km s-1) at the southeast end of the strait. The underlying basement rocks, probably representing the Wrangellia terrane, have velocities of 5.5-6.5 km-1 with considerable lateral variation. Our tomographic model reveals that the Strait of Georgia is underlain by a fault-bounded block within the central Georgia Basin. It also shows a correlation between microearthquakes and areas of rapid change in basin thickness. The 1997/1975 earthquakes are located near a northeast-trending hinge line where the thicknesses of sedimentary rocks increase rapidly to the southeast. Given its association with instrumentally recorded, moderate sized earthquakes, we infer that the hinge region is cored by an active fault that we informally name the Gabriola Island fault. A northwest-trending, southwest dipping velocity discontinuity along the eastern side of Vancouver Island correlates spatially with the surface expression of the Outer Island fault. The Outer Island

  12. Antarctic Single Frames = Frame Level Records of Antarctica Photos: 1946 - 2000

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Aerial photographs of Antarctica from the United States Antarctic Resource Center (USARC) and the British Antarctic Survey (BAS) are maintained in this collection....

  13. Greenland and Antarctica Ice Sheet Mass Changes and Effects on Global Sea Level

    DEFF Research Database (Denmark)

    Forsberg, René; Sørensen, Louise Sandberg; Simonsen, Sebastian Bjerregaard

    2017-01-01

    Thirteen years of GRACE data provide an excellent picture of the current mass changes of Greenland and Antarctica, with mass loss in the GRACE period 2002–2015 amounting to 265 ± 25 GT/year for Greenland (including peripheral ice caps), and 95 ± 50 GT/year for Antarctica, corresponding to 0.......72 and 0.26 mm/year average global sea level change. A significant acceleration in mass loss rate is found, especially for Antarctica, while Greenland mass loss, after a corresponding acceleration period, and a record mass loss in the summer of 2012, has seen a slight decrease in short-term mass loss trend....... The yearly mass balance estimates, based on point mass inversion methods, have relatively large errors, both due to uncertainties in the glacial isostatic adjustment processes, especially for Antarctica, leakage from unmodelled ocean mass changes, and (for Greenland) difficulties in separating mass signals...

  14. Radiocarbon-dates of snow petrel regurgitations can reveal exposure periods for nunataks in Antarctica

    CSIR Research Space (South Africa)

    Ryan, PG

    1992-11-01

    Full Text Available There are several problems associated with determining radiocarbon dates, particularly for organic material from Antarctica. However, this study attempts to find accurate measure of the length of time these radiocarbon dates have been established...

  15. Characteristics of macrobenthic assemblage from sub-littoral sediment off the Lazarev Sea, East Antarctica

    Digital Repository Service at National Institute of Oceanography (India)

    Ingole, B.S.

    Comparative account of the occurrence and abundance of benthic macro-organisms collected from the Lazarev Sea in Queen Maud Land, (east Antarctica), during austral summer of 1984-85 and 1992-93 (fourth and twelfth Indian Antarctic expeditions...

  16. From sea to land: assessment of the bio-transport of phosphorus by penguins in Antarctica

    Science.gov (United States)

    Qin, Xianyan; Sun, Liguang; Blais, Jules M.; Wang, Yuhong; Huang, Tao; Huang, Wen; Xie, Zhouqing

    2014-01-01

    In Antarctica, the marine ecosystem is dynamically interrelated with the terrestrial ecosystem. An example of the link between these two ecosystems is the biogeochemical cycle of phosphorus. Biovectors, such as penguins, transport phosphorus from sea to land, play a key role in this cycle. In this paper, we selected three colonies of penguins, the most important seabirds in Antarctica, and computed the annual quantity of phosphorus transferred from sea to land by these birds. Our results show that adult penguins from colonies at Ardley Island, the Vestfold Hills, and Ross Island could transfer phosphorus in the form of guano at up to 12 349, 167 036, and 97 841 kg/a, respectively, over their breeding period. These quantities are equivalent to an annual input of 3.96×109-1.63×1010 kg of seawater to the land of Antarctica. Finally, we discuss the impact of phosphorus on the ice-free areas of the Antarctica.

  17. Ecobiological assessment of a freshwater lake at Schirmacher Oasis, East Antarctica, with reference to human activities

    Digital Repository Service at National Institute of Oceanography (India)

    Ingole, B.S.; Dhargalkar, V.K.

    The scale and magnitude of probable impact of human activities over a decade (1983-1994) on the freshwater lake Priyadarshini, at Schirmacher Oasis, East Antarctica, was assessed through an ecological study conducted over an annual cycle during...

  18. Mineral dust variability in central West Antarctica associated with ozone depletion

    Directory of Open Access Journals (Sweden)

    M. Cataldo

    2012-05-01

    Full Text Available Here we show that mineral dust retrieved from an ice core in the central West Antarctic sector, spanning the last five decades, provides evidence that northerly air mass incursions into Antarctica, tracked by dust microparticles, have slightly declined. This result contrasts with dust in ice core records reported in West/coastal Antarctica, which show significant increases to the present day. We attribute that difference, in part, to changes in the regional climate regime triggered by the ozone depletion and its consequences for the polar vortex intensity. The vortex maintains the Antarctic central region relatively isolated from mid-latitude air mass incursions with implications to the intensification of the Westerlies and to a persistent positive phase of the Southern Annular Mode. We also show that variability of the diameter of insoluble microparticles in central West Antarctica can be modeled by linear/quadratic functions of both cyclone depth (energy and wind intensity around Antarctica.

  19. Cloning and molecular genetics analyses of Deschampsia antarctica Desv. chloroplast and mitochondrial DNA sequence

    Directory of Open Access Journals (Sweden)

    O.P. Savchuk

    2012-03-01

    Full Text Available Chloroplast and mitochondrial DNA sequences of Deschampsia antarctica were studied. We had made comparison analysis with completely sequenced genomes of other temperateness plants to find homology.

  20. Short term variation in particulate matter in the shelf waters of the Princess Astrid Coast, Antarctica

    Digital Repository Service at National Institute of Oceanography (India)

    Dhargalkar, V.K.; Bhosle, N.B.

    Particulate matter collected at a single station in the shelf waters of Princess Astrid coast (70 degrees S, 11 degrees E) Antarctica, during the austral summer (Jan.-Feb. 1986) was analysed for phytoplankton biomass (Chl @ia@@), living carbon (ATP...

  1. Formation, topography and reactivity of Candida antarctica lipase B immobilized on silicon surface

    NARCIS (Netherlands)

    Miletic, Nemanja; Fahriansyah, [No Value; Nguyen, Le-Thu T.; Loos, Katja; Miletić, Nemanja

    2010-01-01

    Candida antarctica lipase B (CaLB) was immobilized on silicon wafers previously modified with aminopropyltriethoxysilane (APTES) and activated with glutaraldehyde (GLA). The various steps of immobilization were characterized using transmission FTIR, AFM, contact angle measurements and XPS. Furthermo

  2. Antarctic Flight Line Maps = Map-Line Indexes of Antarctica Aerial Photos: Pre 1950

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The Antarctic Fight Line Maps collection is comprised of 1:250,000 scale topographic maps over Antarctica with original hand-drawn flight lines for aerial...

  3. Don Juan Basin, Wright Valley, Antarctica: Model for Surface Processes on Mars

    Science.gov (United States)

    Englert, P.; Bishop, J. L.; Gibson, E. K.; Patel, S.; Koeberl, C.

    2014-09-01

    Mineral, chemical, and soluble salt composition of drill core samples from Don Juan Basin, Wright Valley, Antarctica, indicate that the formation of the most saline terrestrial pond may include groundwater discharge and near surface flow processes.

  4. Antarctic Flight Line Maps = Map-Line Indexes of Antarctica Aerial Photos: Pre 1950

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The Antarctic Fight Line Maps collection is comprised of 1:250,000 scale topographic maps over Antarctica with original hand-drawn flight lines for aerial...

  5. Geodetic and geophysical observations in Antarctica an overview in the IPY perspective

    CERN Document Server

    Capra, Alessandro

    2008-01-01

    This book is a collection of papers on various aspects of the geodetic and geophysical investigation and observation techniques. It includes material from the Arctic and Antarctica, as well as covering work from both temporary and permanent observatories.

  6. Formation, topography and reactivity of Candida antarctica lipase B immobilized on silicon surface

    NARCIS (Netherlands)

    Miletic, Nemanja; Fahriansyah, [No Value; Nguyen, Le-Thu T.; Loos, Katja; Miletić, Nemanja

    2010-01-01

    Candida antarctica lipase B (CaLB) was immobilized on silicon wafers previously modified with aminopropyltriethoxysilane (APTES) and activated with glutaraldehyde (GLA). The various steps of immobilization were characterized using transmission FTIR, AFM, contact angle measurements and XPS.

  7. Extraction of intracellular protein from Glaciozyma antarctica for proteomics analysis

    Science.gov (United States)

    Faizura, S. Nor; Farahayu, K.; Faizal, A. B. Mohd; Asmahani, A. A. S.; Amir, R.; Nazalan, N.; Diba, A. B. Farah; Muhammad, M. Nor; Munir, A. M. Abdul

    2013-11-01

    Two preparation methods of crude extracts of psychrophilic yeast Glaciozyma antarctica were compared in order to obtain a good recovery of intracellular proteins. Extraction with mechanical procedures using sonication was found to be more effective for obtaining good yield compare to alkaline treatment method. The procedure is simple, rapid, and produce better yield. A total of 52 proteins were identified by combining both extraction methods. Most of the proteins identified in this study involves in the metabolic process including glycolysis pathway, pentose phosphate pathway, pyruyate decarboxylation and also urea cyle. Several chaperons were identified including probable cpr1-cyclophilin (peptidylprolyl isomerase), macrolide-binding protein fkbp12 and heat shock proteins which were postulate to accelerate proper protein folding. Characteristic of the fundamental cellular processes inferred from the expressed-proteome highlight the evolutionary and functional complexity existing in this domain of life.

  8. The Landsat Image Mosaic of the Antarctica Web Portal

    Directory of Open Access Journals (Sweden)

    Christopher J Rusanowski

    2007-06-01

    Full Text Available People believe what they can see. The Poles exist as a frozen dream to most people. The International Polar Year wants to break the ice (so to speak, open up the Poles to the general public, support current polar research, and encourage new research projects.  The IPY officially begins in March, 2007. As part of this effort, the U.S. Geological Survey (USGS and the British Antarctic Survey (BAS, with funding from the National Science Foundation (NSF, are developing three Landsat mosaics of Antarctica and an Antarctic Web Portal with a Community site and an online map viewer. When scientists are able to view the entire scope of polar research, they will be better able to collaborate and locate the resources they need. When the general public more readily sees what is happening in the polar environments, they will understand how changes to the polar areas affect everyone.

  9. An unusual, structurally preserved ovule from the Permian of Antarctica.

    Science.gov (United States)

    Klavins, S D.; Taylor, E L.; Krings, M; Taylor, T N.

    2001-06-01

    Anatomically preserved ovules are described from silicified peat of Late Permian age collected from Skaar Ridge in the central Transantarctic Mountains, Antarctica. The small ovules are significant in possessing fleshy apical appendages and a funnel-shaped micropylar extension formed by the sarcotestal layer of the integument, by which they differ from all other Permian ovules described to date. The apical modifications may have functioned in pollination and/or seed dispersal. Similarity with the apical organization of earlier Paleozoic ovules is shown to be superficial, since the analogous structures are developmentally derived from different tissues. Although the ovules occur in rocks in which glossopterids are the only gymnosperms represented, there is insufficient evidence to assign them to a taxonomic group. These ovules are of particular importance because there are so few anatomically preserved gymnosperm reproductive structures known from the Permian and thus provide new data on the diversity of late Paleozoic gymnosperms.

  10. The landsat image mosaic of the Antarctica Web Portal

    Science.gov (United States)

    Rusanowski, C.J.

    2007-01-01

    People believe what they can see. The Poles exist as a frozen dream to most people. The International Polar Year wants to break the ice (so to speak), open up the Poles to the general public, support current polar research, and encourage new research projects. The IPY officially begins in March, 2007. As part of this effort, the U.S. Geological Survey (USGS) and the British Antarctic Survey (BAS), with funding from the National Science Foundation (NSF), are developing three Landsat mosaics of Antarctica and an Antarctic Web Portal with a Community site and an online map viewer. When scientists are able to view the entire scope of polar research, they will be better able to collaborate and locate the resources they need. When the general public more readily sees what is happening in the polar environments, they will understand how changes to the polar areas affect everyone.

  11. Aerobiology over Antarctica – a new initiative for atmospheric ecology

    Directory of Open Access Journals (Sweden)

    David Anthony Pearce

    2016-02-01

    Full Text Available The role of aerial dispersal in shaping patterns of biodiversity remains poorly understood, mainly due to a lack of coordinated efforts in gathering data at appropriate temporal and spatial scales. It has been long known that the rate of dispersal to an ecosystem can significantly influence ecosystem dynamics, and that aerial transport has been identified as an important source of biological input to remote locations. With the considerable effort devoted in recent decades to understanding atmospheric circulation in the south polar region, a unique opportunity has emerged to investigate the atmospheric ecology of Antarctica, from local to continental scales. This concept note identifies key questions in Antarctic microbial biogeography and the need for standardized sampling and analysis protocols to address such questions. A consortium of polar aerobiologists is established to bring together researchers with a common interest in the airborne dispersion of microbes and other propagules in the Antarctic, with opportunities for comparative studies in the Arctic.

  12. Surface and snowdrift sublimation at Princess Elisabeth station, East Antarctica

    Directory of Open Access Journals (Sweden)

    W. Thiery

    2012-08-01

    Full Text Available In the near-coastal regions of Antarctica, a significant fraction of the snow precipitating onto the surface is removed again through sublimation – either directly from the surface or from drifting snow particles. Meteorological observations from an Automatic Weather Station (AWS near the Belgian research station Princess Elisabeth in Dronning Maud Land, East-Antarctica, are used to study surface and snowdrift sublimation and to assess their impacts on both the surface mass balance and the surface energy balance during 2009 and 2010. Comparison to three other AWSs in Dronning Maud Land with 11 to 13 yr of observations shows that sublimation has a significant influence on the surface mass balance at katabatic locations by removing 10–23% of their total precipitation, but at the same time reveals anomalously low surface and snowdrift sublimation rates at Princess Elisabeth (17 mm w.e. yr−1 compared to 42 mm w.e. yr−1 at Svea Cross and 52 mm w.e. yr−1 at Wasa/Aboa. This anomaly is attributed to local topography, which shields the station from strong katabatic influence, and, therefore, on the one hand allows for a strong surface inversion to persist throughout most of the year and on the other hand causes a lower probability of occurrence of intermediately strong winds. This wind speed class turns out to contribute most to the total snowdrift sublimation mass flux, given its ability to lift a high number of particles while still allowing for considerable undersaturation.

  13. Uncovering the footprint of former ice streams off Antarctica

    Science.gov (United States)

    COHIMAR/SEDANO Scientific Party

    Antarctic ice sheets and ice caps have been expanding and contracting following global climatic cycles. The last time the Antarctic ice cover peaked, at least in Western Antarctica, was ca. 21 ky ago during the Last Glacial Maximum (LGM). The strong warming (nearly 2.8°C) over the past 50 years, and the yearly recent collapse of limited portions (hundreds to a few thousands of square miles per event) of ice shelves around the Antarctic Peninsula have brought to the headlines the debate about the potential collapse of the West Antarctic Ice Sheet (WAIS) in the near future under the influence of global warming.Such a catastrophe would substantially contribute to global sea level rise (a resulting 5 m increase is expected); alter water mass conditions, circulation, and productivity around Antarctica and in the world ocean; and modify the Earth's climate.The economic,social, and ecological impacts of these changes would depend greatly on the rate at which they might take place [Bindschadler, 1998” . A detailed knowledge of the past extent of ice sheets and the timing of their advances and retreats thus becomes essential to quantify the rates of change and to properly assess the future stability of the WAIS and nearby ice caps. The stability of ice sheets is largely dependent on ice drainage, which mostly occurs via ice streaming along glacial troughs. Ice streams are thus a key element to solve the puzzle linking ice sheet stability, sea level rise, and climate change at a global scale.

  14. Electrical structure beneath Schirmacher Oasis, East Antarctica: a magnetotelluric study

    Directory of Open Access Journals (Sweden)

    D.N. Murthy

    2013-11-01

    Full Text Available Maitri Station (70.76°S; 11.73°E is located in Schirmacher Oasis, a coastal nunatak in north-central Dronning Maud Land covering an area of 35 km2. Here, we report results from the first magnetotelluric experiments and delineate the deep electrical conductivity structure under Schirmacher Oasis using the data acquired during the 24th Indian Antarctic Scientific Expedition. The magnetotelluric method has the advantage of shallow to deeper level coverage as the data acquisition covers a wide frequency band of 10−3–103 Hz, permitting different penetration depths depending on the frequency and conductivity of the layer under investigation. The modelling results indicate the presence of a highly resistive (8000–10 000 ohm m upper crust, which shows a lateral variation in thickness from 20 km (below site 6 in the east to 10 km (between sites 1 and 2 in the west. It is underlain by a less resistive (500–600 ohm m lower crust. The highly resistive upper crustal structure supports the existing notion that western Dronning Maud Land is a stable, cratonic platform. Results of free-air gravity, seismic, geomagnetic and surface wave dispersion investigations in East Antarctica also indicate a cratonic-type crust. The results of our study allow us to identify a westward thinning of the upper crust with a marked boundary between sites 1 and 2. We also find evidence for the continuity of the Mozambique mobile belt in East Antarctica on the western side of Schirmacher Oasis.

  15. Microzooplankton herbivory and community structure in the Amundsen Sea, Antarctica

    Science.gov (United States)

    Yang, Eun Jin; Jiang, Yong; Lee, SangHoon

    2016-01-01

    We examined microzooplankton abundance, community structure, and grazing impact on phytoplankton in the Amundsen Sea, Western Antarctica, during the early austral summer from December 2010 to January 2011. Our study area was divided into three regions based on topography, hydrographic properties, and trophic conditions: (1) the Oceanic Zone (OZ), with free sea ice and low phytoplankton biomass dominated by diatoms; (2) the Sea Ice Zone (SIZ), covered by heavy sea ice with colder water, lower salinity, and dominated by diatoms; and (3) the Amundsen Sea Polynya (ASP), with high phytoplankton biomass dominated by Phaeocystis antarctica. Microzooplankton biomass and communities associated with phytoplankton biomass and composition varied among regions. Heterotrophic dinoflagellates (HDF) were the most significant grazers in the ASP and OZ, whereas ciliates co-dominated with HDF in the SIZ. Microzooplankton grazing impact is significant in our study area, particularly in the ASP, and consumed 55.4-107.6% of phytoplankton production (average 77.3%), with grazing impact increasing with prey and grazer biomass. This result implies that a significant proportion of the phytoplankton production is not removed by sinking or other grazers but grazed by microzooplankton. Compared with diatom-based systems, Phaeocystis-based production would be largely remineralized and/or channeled through the microbial food web through microzooplankton grazing. In these waters the major herbivorous fate of phytoplankton is likely mediated by the microzooplankton population. Our study confirms the importance of herbivorous protists in the planktonic ecosystems of high latitudes. In conclusion, microzooplankton herbivory may be a driving force controlling phytoplankton growth in early summer in the Amundsen Sea, particularly in the ASP.

  16. Hydrological Controls on Ecosystem Dynamics in Lake Fryxell, Antarctica.

    Directory of Open Access Journals (Sweden)

    Radu Herbei

    Full Text Available The McMurdo Dry Valleys constitute the largest ice free area of Antarctica. The area is a polar desert with an annual precipitation of ∼ 3 cm water equivalent, but contains several lakes fed by glacial melt water streams that flow from four to twelve weeks of the year. Over the past ∼20 years, data have been collected on the lakes located in Taylor Valley, Antarctica as part of the McMurdo Dry Valley Long-Term Ecological Research program (MCM-LTER. This work aims to understand the impact of climate variations on the biological processes in all the ecosystem types within Taylor Valley, including the lakes. These lakes are stratified, closed-basin systems and are perennially covered with ice. Each lake contains a variety of planktonic and benthic algae that require nutrients for photosynthesis and growth. The work presented here focuses on Lake Fryxell, one of the three main lakes of Taylor Valley; it is fed by thirteen melt-water streams. We use a functional regression approach to link the physical, chemical, and biological processes within the stream-lake system to evaluate the input of water and nutrients on the biological processes in the lakes. The technique has been shown previously to provide important insights into these Antarctic lacustrine systems where data acquisition is not temporally coherent. We use data on primary production (PPR and chlorophyll-A (CHLfrom Lake Fryxell as well as discharge observations from two streams flowing into the lake. Our findings show an association between both PPR, CHL and stream input.

  17. The environmental impact of sewage and wastewater outfalls in Antarctica: An example from Davis station, East Antarctica.

    Science.gov (United States)

    Stark, Jonathan S; Corbett, Patricia A; Dunshea, Glenn; Johnstone, Glenn; King, Catherine; Mondon, Julie A; Power, Michelle L; Samuel, Angelingifta; Snape, Ian; Riddle, Martin

    2016-11-15

    We present a comprehensive scientific assessment of the environmental impacts of an Antarctic wastewater ocean outfall, at Davis station in East Antarctica. We assessed the effectiveness of current wastewater treatment and disposal requirements under the Protocol on Environmental Protection to the Antarctic Treaty. Macerated wastewater has been discharged from an outfall at Davis since the failure of the secondary treatment plant in 2005. Water, sediment and wildlife were tested for presence of human enteric bacteria and antibiotic resistance mechanisms. Epibiotic and sediment macrofaunal communities were tested for differences between sites near the outfall and controls. Local fish were examined for evidence of histopathological abnormalities. Sediments, fish and gastropods were tested for uptake of sewage as measured by stable isotopes of N and C. Escherichia coli carrying antibiotic resistance determinants were found in water, sediments and wildlife (the filter feeding bivalve Laternula eliptica). Fish (Trematomus bernacchii) within close proximity to the outfall had significantly more severe and greater occurrences of histopathological abnormalities than at controls, consistent with exposure to sewage. There was significant enrichment of (15)N in T. bernacchii and the predatory gastropod Neobuccinum eatoni around the outfall, providing evidence of uptake of sewage. There were significant differences between epibiotic and sediment macrofaunal communities at control and outfall sites (environmental drivers such as sea ice. The combined evidence indicated that the discharge of wastewater from the Davis outfall is causing environmental impacts. These findings suggest that conditions in Antarctic coastal locations, such as Davis, are unlikely to be conducive to initial dilution and rapid dispersal of wastewater as required under the Protocol on Environmental Protection to the Antarctic Treaty. Current minimum requirements for wastewater treatment and disposal in

  18. Antarctica Meta-Analysis: Psychosocial Factors Related to Long Duration Isolation and Confinement

    Science.gov (United States)

    Leveton, Lauren; Shea, Camille; Slack, Kelley J.; Keeton, Kathryn E.; Palinkas, Lawrence A.

    2009-01-01

    This meta-analysis is examining the psychological effects of wintering-over in Antarctica. As an isolated, confined, and extreme (ICE) environment, Antarctica provides invaluable opportunities to experience stressors more common to spaceflight than to the average person s everyday life. Increased prevalence of psychological symptoms, syndromes, and psychiatric disorders, as well as positive effects, are expected to be associated with various demographic and environmental factors. Implications for spaceflight are discussed. Findings from statistical review of the Antarctic articles will be shared.

  19. Characterization of Ionosphere Waveguide Propagation by Monitoring HAARP HF Transmissions in Antarctica

    Science.gov (United States)

    2015-04-17

    AFRL-AFOSR-UK-TR-2015-0024 CHARACTERIZATION OF IONOSPHERE WAVEGUIDE PROPAGATION BY MONITORING HAARP HF TRANSMISSIONS IN ANTARCTICA *Yuri M...31 December 2014 4. TITLE AND SUBTITLE CHARACTERIZATION OF IONOSPHERE WAVEGUIDE PROPAGATION BY MONITORING HAARP HF TRANSMISSIONS IN ANTARCTICA 5a...investigating the possibility of exciting the ionospheric interlayer duct channel using powerful radiation from the heaters HAARP (Alaska, USA) and EISCAT

  20. Digital filter technology and its application to geomagnetic pulsations in Antarctica

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Digital filter technology is an important method in study of geomagnetic pulsations in Antarctica. The signals received by pulsation magnetometer on the ground include various types of magnetic pulsations. Some types of pulsations or some frequency hands of pulsations can be extracted from the signals by means of digital filter technology because types of pulsations are defined according to their frequency range. In this paper usual digital filter technology is provided for study of magnetic pulsations in Antarctica and some examples are introduced.

  1. Tufted hairgrass (Deschampsia caespitosa) exhibits a lower photosynthetic plasticity than Antarctic hairgrass (D. antarctica).

    Science.gov (United States)

    Bystrzejewska-Piotrowska, Grazyna; Urban, Pawel L

    2009-06-01

    The aim of our work was to assess photosynthetic plasticity of two hairgrass species with different ecological origins (a temperate zone species, Deschampsia caespitosa (L.) Beauv. and an Antarctic species, D. antarctica) and to consider how the anticipated climate change may affect vitality of these plants. Measurements of chlorophyll fluorescence showed that the photosystem II (PSII) quantum efficiency of D. caespitosa decreased during 4 d of incubation at 4 degrees C but it remained stable in D. antarctica. The fluorescence half-rise times were almost always lower in D. caespitosa than in D. antarctica, irrespective of the incubation temperature. These results indicate that the photosynthetic apparatus of D. caespitosa has poorer performance in these conditions. D. caespitosa reached the maximum photosynthesis rate at a higher temperature than D. antarctica although the values obtained at 8 degrees C were similar in both species. The photosynthetic water-use efficiency (photosynthesis-to-transpiration ratio, P/E) emerges as an important factor demonstrating presence of mechanisms which facilitate functioning of a plant in non-optimal conditions. Comparison of the P/E values, which were higher in D. antarctica than in D. caespitosa at low and medium temperatures, confirms a high degree of adjustability of the photosynthetic apparatus in D. antarctica and unveils the lack of such a feature in D. caespitosa.

  2. Tufted Hairgrass (Deschampsia caespitosa) Exhibits a Lower Photosynthetic Plasticity than Antarctic Hairgrass (D. Antarctica)

    Institute of Scientific and Technical Information of China (English)

    Gra(z)yna Bystrzejewska-Piotrowska; Pawel L. Urban

    2009-01-01

    The aim of our work was to assess photosynthetic plasticity of two hairgrass species with different ecological origins (a temperate zone species, Deschampsia caespitosa (L.) Beauv. and an Antarctic species, D. antarctica) and to consider how the anticipated climate change may affect vitality of these plants. Measurements of chlorophyll fluorescence showed that the photosystem Ⅱ (PSII) quantum efficiency of D. caespitosa decreased during 4 d of incubation at 4℃ but it remained stable in D. antarctica. The fluorescence half-rise times were almost always lower in D. caespitosa than in D. antarctica,irrespective of the incubation temperature. These results indicate that the photosynthetic apparatus of D. caespitosa has poorer performance in these conditions. D. caespitosa reached the maximum photosynthesis rate at a higher temperature than D. antarctica although the values obtained at 8℃ were similar in both species. The photosynthetic water-use efficiency (photosynthesis-to-transpiration ratio, P/E) emerges as an important factor demonstrating presence of mechanisms which facilitate functioning of a plant in non-optimal conditions. Comparison of the P/E values, which were higher in D. antarctica than in D. caespitosa at low and medium temperatures, confirms a high degree of adjustability of the photosynthetic apparatus in D. antarctica and unveils the lack of such a feature in D. caespitosa.

  3. Parasites of the hard clam Meretrix meretrix Linnaeus from Western Johor Straits, Malaysian

    Science.gov (United States)

    Azmi, Nur Fauzana; Ghaffar, Mazlan Abd.; Cob, Zaidi Che

    2014-09-01

    This study describes the apicomplexa as well as other parasites infecting organs/tissues of the hard clam Meretrix meretrix Linnaeus, from Merambong Shoal, Western Johor Straits, Malaysia. Samples were collected randomly by hand picking, in November and December 2013. Histological techniques were performed, stained using Masson's Trichrome protocol and observed under light microscope. The results showed that gonad and gill were the most infected organs followed by digestive gland, intestine and adductor muscle. No pathology condition was observed in the mantle. Histophatological examination showed that the gregarine, Nematopsis, unidentified coccidian and Perkinsus were found in the gill and gonad, and also in the numerous hemocytes. Other pathological conditions such as bacteria-like inclusion and intracellular bacteria were also observed in the same organs. Further investigations are needed particularly on other molluscs present at the study area. Understanding the morphology and pathology of parasites infecting mollusks are very important for management of the resources.

  4. The Straits Chinese Contribution to Malaysian Literary Heritage: Focus on Chinese Stories Translated into Baba Malay

    Directory of Open Access Journals (Sweden)

    S.K. Yoong

    2004-12-01

    Full Text Available The Chinese born in the Straits Settlements of Peninsula Malaya (Penang, Singapore, Malacca are called Babas to distinguish them from those born in China. The Babas are rooted from three different races, Chinese, Malay and English and as such their lifestyles show a mixed blend of the Chinese, Malay and European cultures. Because of this cultural background, the Babas exhibited a unique cultural mix in the clothes they wear, their culinary skills, architectural styles, language and literature. The paper describes the characteristics of 68 Baba translated works published between 1889 and 1950; focusing on the publication trends between the period under study, the persons involved in the creative output, the publishers and printers involved, the contents of the translated works, the physical make-up of the works and the libraries where these works are held.

  5. Appropriate Health Promotion for Australian Aboriginal and Torres Strait Islander Communities

    DEFF Research Database (Denmark)

    Demaio, Alessandro Rhyll; Drysdale, Marlene; de Courten, Maximilian

    2012-01-01

    Health promotion for Australian Aboriginal and Torres Strait Islander communities and their people has generally had limited efficacy and poor sustainability. It has largely failed to recognise and appreciate the importance of local cultures and continues to have minimal emphasis on capacity...... building, community empowerment and local ownership. Culturally-Appropriate Health Promotion is a framework of principles developed in 2008 with the World Health Organization (Geneva) and Global Alliance for Health Promotion. It guides community-focused health promotion practice built on and shaped...... by the respect, understanding and utilisation of local knowledge and culture. Culturally-Appropriate Health Promotion is not about ‘targeting’, ‘intervening’ or ‘responding’. Rather, it results in health program planners and policy-makers understanding, respecting, empowering and collaborating with communities...

  6. Plastic debris and microplastics along the beaches of the Strait of Hormuz, Persian Gulf.

    Science.gov (United States)

    Naji, Abolfazl; Esmaili, Zinat; Khan, Farhan R

    2017-01-30

    Currently little is known about the prevalence of plastics and microplastics (MPs) in the Persian Gulf. Five sampling stations were selected along the Strait of Hormuz (Iran) that exhibited different levels of industrialization and urbanization, and included a marine protected area. Debris was observed and sediments were collected for MPs extraction via fluidization/floatation methodology. The order of MP abundance (par/kg) generally reflected the level of anthropogenic activity: Bostanu (1258±291)>Gorsozan (122±23)>Khor-e-Yekshabeh (26±6)>Suru (14±4)>Khor-e-Azini (2±1). Across all sites fibers dominated (83%, 11% film, 6% fragments). FT-IR analysis showed polyethylene (PE), nylon, and PET (polyethylene terephthalate) were the commonly recovered polymers. Likely sources include beach debris, discarded fishing gear, and urban and industrial outflows that contain fibers from clothes. This study provides a 'snapshot' of MP pollution and longitudinal studies are required to fully understand plastic contamination in the region.

  7. Mitochondrial DNA haplotyping of Testudo graeca on both continental sides of the Straits of Gibraltar.

    Science.gov (United States)

    Alvarez, Y; Mateo, J A; Andreu, A C; Díaz-Paniagua, C; Diez, A; Bautista, J M

    2000-01-01

    Testudo graeca is an endangered species of tortoise that inhabits Mediterranean areas of Africa, Asia, and Europe. Western populations are found on both sides of the Straits of Gibraltar. The effects of geographical isolation on genetic divergence were assessed by the sequence analysis of two mitochondrial DNA regions of the 12S rRNA and cytochrome b genes. Four different haplotypes were identified. A single haplotype was shared by all Spanish and some east Moroccan specimens. Two haplotypes were unique to the west Moroccan T. graeca populations and allowed the clear discrimination between individual specimens found west of the Moulouya River. Phylogenetic analysis based on the estimation of nucleotide sequence distances of the haplotypes suggests an African origin for the Spanish populations and a subspecies status for the west Moroccan pool.

  8. Meteorologically-driven circulation and flushing times of the Bay of Algeciras, Strait of Gibraltar.

    Science.gov (United States)

    Sánchez-Garrido, José C; Lafuente, Jesús García; Sammartino, Simone; Naranjo, Cristina; de los Santos, Francisco J; Álvarez Fanjul, Enrique

    2014-03-15

    A primitive-equation model has been used to investigate the meteorologically-driven circulation of the Bay of Algeciras. It is shown that the mean circulation of Atlantic Water (AW) is characterized by an anticyclonic cell, while Mediterranean Water (MW) follows a preferred cyclonic pathway. Meteorological forcing distorts substantially the AW mean circulation pattern, and only modulates that of the MW. Winds drive a vertical circulation cell in the Atlantic layer consistent with Ekman dynamics, whereas the horizontal circulation pattern is markedly dependent on the swift Atlantic jet entering the Mediterranean and changes from clearly anticyclonic to cyclonic as the jet separates or approaches the strait's northern shoreline. This occurs through atmospheric pressure-driven acceleration/deceleration of the jet, in agreement with internal hydraulics theory predictions. It is also found that the renewal of AW is largely modulated by tides, with meteorological forcing playing a secondary role. The opposite applies to the renewal of MW.

  9. Test of numerical prediction of sea water temperature in the Taiwan Strait

    Institute of Scientific and Technical Information of China (English)

    Wang Xiuqin; Huang Huowang; Dong Jian; Qian Chengchun

    2001-01-01

    A dynamic numerical prediction model of sea water temperature for limited sea area is used to predict the sea water temperature at the sea area near Fujian. Essential adjustments have been made in accordance with the characteristics of this region. Two tests have been made. One is in summer (3 d) and the other is in winter (10 d). In the summer test, a typhoon is just passing by and the calculated current field well responds to typhoon. In the winter test, variation tendency of the predicted sea water temperature field agrees with that of the observation basically, the absolute mean error in the whole sea area is 0.6 ℃. The variation of the sea water temperature is mostly affected by entrainment and pumping, which is related to the topography of the strait.

  10. Statistical analysis of strait time index and a simple model for trend and trend reversal

    Science.gov (United States)

    Chen, Kan; Jayaprakash, C.

    2003-06-01

    We analyze the daily closing prices of the Strait Time Index (STI) as well as the individual stocks traded in Singapore's stock market from 1988 to 2001. We find that the Hurst exponent is approximately 0.6 for both the STI and individual stocks, while the normal correlation functions show the random walk exponent of 0.5. We also investigate the conditional average of the price change in an interval of length T given the price change in the previous interval. We find strong correlations for price changes larger than a threshold value proportional to T; this indicates that there is no uniform crossover to Gaussian behavior. A simple model based on short-time trend and trend reversal is constructed. We show that the model exhibits statistical properties and market swings similar to those of the real market.

  11. Large-scale, realistic laboratory modeling of M2 internal tide generation at the Luzon Strait

    CERN Document Server

    Mercier, Matthieu J; Helfrich, Karl; Sommeria, Joël; Viboud, Samuel; Didelle, Henri; Saidi, Sasan; Dauxois, Thierry; Peacock, Thomas

    2015-01-01

    The complex double-ridge system in the Luzon Strait in the South China Sea (SCS) is one of the strongest sources of internal tides in the oceans, associated with which are some of the largest amplitude internal solitary waves on record. An issue of debate, however, has been the specific nature of their generation mechanism. To provide insight, we present the results of a large-scale laboratory experiment performed at the Coriolis platform. The experiment was carefully designed so that the relevant dimensionless parameters, which include the excursion parameter, criticality, Rossby, and Froude numbers, closely matched the ocean scenario. The results advocate that a broad and coherent weakly nonlinear, three-dimensional, M2 internal tide that is shaped by the overall geometry of the double-ridge system is radiated into the South China Sea and subsequently steepens, as opposed to being generated by a particular feature or localized region within the ridge system.

  12. On extreme atmospheric and marine nitrogen fluxes and chlorophyll-a levels in the Kattegat Strait

    DEFF Research Database (Denmark)

    Hasager, C.B.; Carstensen, J.; Ellermann, T.

    2003-01-01

    A retrospective analysis is carried out to investigate the importance of the vertical fluxes of nitrogen to the marine sea surface layer in which high chlorophyll a levels may cause blooms of harmful algae and subsequent turn over and oxygen depletion at the bottom of the sea. Typically nitrogen...... are calculated by the periodic maximum method and the results are successfully compared to a map of chlorophyll return periods based on in-situ observations. The one-year return of extreme atmospheric wet deposition is around 60 mg N m(-2) day(-1) and 30 mg N m(-2) day(-1) for deep-water entrainment. Atmospheric......-water entrainment forced by high winds greatly exceeds the atmospheric pool of nitrogen washed out by precipitation. At the frontal zone of the Kattegat Strait and Skagerrak, the nitrogen deep-water entrainment is very high and this explains the high 10-year return chlorophyll level at 8 mg m(-3) in the Kattegat...

  13. Probability Models for the Distribution of Copepods in Different Coastal Ecosystems Along the Straits of Malacca

    Science.gov (United States)

    Matias-Peralta, Hazel Monica; Ghodsi, Alireza; Shitan, Mahendran; Yusoff, Fatimah Md.

    Copepods are the most abundant microcrustaceans in the marine waters and are the major food resource for many commercial fish species. In addition, changes in the distribution and population composition of copepods may also serve as an indicator of global climate changes. Therefore, it is important to model the copepod distribution in different ecosystems. Copepod samples were collected from three different ecosystems (seagrass area, cage aquaculture area and coastal waters off shrimp aquaculture farm) along the coastal waters of the Malacca Straits over a one year period. In this study the major statistical analysis consisted of fitting different probability models. This paper highlights the fitting of probability distributions and discusses the adequateness of the fitted models. The usefulness of these fitted models would enable one to make probability statements about the distribution of copepods in three different ecosystems.

  14. The Application of Fucus vesiculosus as a Bioindicator of 60Co Concentrations in the Danish Straits

    DEFF Research Database (Denmark)

    Boelskifte, S.

    1985-01-01

    The occurrence of 60Co in the Danish Straits is investigated by applying the seaweed Fucus vesiculosus as a bioindicator. In order to describe different dispersion situations, three areas have been studied separately: the North Sea, where it is possible to measure 60Co from sources in France and....../or the UK; the Kattegat, where the sources are the Swedish nuclear power plants Ringhals and Barsebäck; and the Sound, where the initial mixing of the release from Barsebäck takes place. A power function can be estimated for the Kattegat and the Sound describing the content of 60Co in Fucus as a function...... of distance from Barsebäck. Problems of uncertainty related to differences in environmental parameters are discussed and new investigations to improve the use of Fucus as a bioindicator are suggested....

  15. A shark in the stars: astronomy and culture in the Torres Strait

    CERN Document Server

    Hamacher, Duane W

    2014-01-01

    Technology has, without doubt, expanded our understanding of space. The Voyager 1 space probe is on the brink of leaving our solar system. Massive telescopes have discovered blasts of fast radio bursts from 10 billion light years away. And after a decade on Mars, a Rover recently found evidence for an early ocean on the Red Planet. But with every new advance, it's also important to remember the science of astronomy has existed for thousands of years and forms a vital part of Indigenous Australian culture, even today. As an example, let's explore the astronomy of the Torres Strait Islanders, an Indigenous Australian people living between the tip of Cape York and Papua New Guinea.

  16. Occurrence of polycyclic aromatic hydrocarbons (PAHs) in seawater from the Western Taiwan Strait, China.

    Science.gov (United States)

    Wu, Yu-Ling; Wang, Xin-Hong; Li, Yong-Yu; Hong, Hua-Sheng

    2011-01-01

    Seawater samples (including surface water and bottom water) were collected from the Western Taiwan Strait (WTS) during June 24-25, 2009; polycyclic aromatic hydrocarbons (PAHs) in dissolved phase and particulate phase were analyzed, respectively. The results showed that the total concentrations of PAHs in the dissolved phase and particulate phase were ranged from 12.3 to 58.0 ng L(-1), and 10.3-45.5 ng L(-1), which showed a low-middle contamination level in the China Seas. The spatial variability of PAHs may be related to the complicated currents of WTS, especially the Min-Zhe coastal current. PAHs diagnostic ratios suggested that PAHs mainly originated from the inputs of pyrolytic (combustion) sources, which might be contributed to land-based atmospheric deposition. The particle-water partition coefficients of individual PAH showed that partitions were not correlated with suspended particulate matter content, dissolved organic carbon or salinity, similar to the Yangtze coastal area.

  17. Manganese, nickel, selenium and cadmium in molluscs from the Magellan Strait, Chile.

    Science.gov (United States)

    Astorga España, M S; Rodríguez Rodríguez, E M; Díaz Romero, C

    2004-08-01

    The concentrations of manganese, selenium, nickel and cadmium were determined in 112 samples of molluscs belonging to mussels (Mytilus chilensis, n = 47) and limpets (Nacella deaurata, n = 65), which were collected from the coastline of the Magellan Strait, Chile. Four (6.2%) samples of limpets exceeded the maximum limits for cadmium established in Europe. Limpets showed higher mean manganese, nickel and cadmium concentrations than mussels, whilst the mean selenium concentration in mussels was higher. The consumption of one serving (100 g) of molluscs represents a considerable contribution to the dietary daily intake of selenium, and limpets make a significant contribution to the manganese and cadmium intakes. The sampling zone influenced the trace element concentrations, and different uptakes were observed between the mollusc species.

  18. Tectonic activity and the evolution of submarine canyons: The Cook Strait Canyon system, New Zealand

    Science.gov (United States)

    Micallef, Aaron; Mountjoy, Joshu; Barnes, Philip; Canals, Miquel; Lastras, Galderic

    2016-04-01

    Submarine canyons are Earth's most dramatic erosional features, comprising steep-walled valleys that originate in the continental shelf and slope. They play a key role in the evolution of continental margins by transferring sediments into deep water settings and are considered important biodiversity hotspots, pathways for nutrients and pollutants, and analogues of hydrocarbon reservoirs. Although comprising only one third of continental margins worldwide, active margins host more than half of global submarine canyons. We still lack of thorough understanding of the coupling between active tectonics and submarine canyon processes, which is necessary to improve the modelling of canyon evolution in active margins and derive tectonic information from canyon morphology. The objectives of this study are to: (i) understand how tectonic activity influences submarine canyon morphology, processes, and evolution in an active margin, and (2) formulate a generalised model of canyon development in response to tectonic forcing based on morphometric parameters. We fulfil these objectives by analysing high resolution geophysical data and imagery from Cook Strait Canyon system, offshore New Zealand. Using these data, we demonstrate that tectonic activity, in the form of major faults and structurally-generated tectonic ridges, leaves a clear topographic signature on submarine canyon location and morphology, in particular their dendritic and sinuous planform shapes, steep and linear longitudinal profiles, and cross-sectional asymmetry and width. We also report breaks/changes in canyon longitudinal slope gradient, relief and slope-area regression models at the intersection with faults. Tectonic activity gives rise to two types of knickpoints in the Cook Strait Canyon. The first type consists of low slope gradient, rounded and diffusive knickpoints forming as a result of short wavelength folds or fault break outs and being restored to an equilibrium profile by upstream erosion and

  19. FCJ-140 Radio Feeds, Satellite Feeds, Network Feeds: Subjectivity Across the Straits of Gibraltar.

    Directory of Open Access Journals (Sweden)

    Nicholas Knouf

    2012-07-01

    Full Text Available This paper engages with the practices surrounding the two fadaiat encounters that took place simultaneously in Spain and Morocco in the summers of 2004 and 2005 (see http://fadaiat.net/ .  The fadaiat project focused on the question of immigration to Europe, specifically from northern Africa, and the ‘Fortress Europe’ responses by European Union governments.  Participants in fadaiat included academic scholars, free software developers, artists, and activists, forming a meta-network that created bridges across disparate communities and practices.  In particular, the participation of the Spanish collective hackitectura was key; they describe themselves as a ‘posse of architects, hackers and social activists experimenting in the merging territories of recombining spatial cyborgs composed by physical spaces, ICT networks and bodies’.  hackitectura led the development of both a temporary civil, non-commercial wireless link across the straits of Gibraltar between Tarifa, Spain and Tangier, Morocco, as well as an entirely free software audio/video streaming system, that enabled participants on both sides to come together independently of the restrictions normally placed on such movement by immigration laws.The importance of free software for fadaiat extends beyond its purely instrumental use as an agent for disrupting state control.  Indeed, the imagery of computation and free software – networks, links, patches, nodes, penguins – pervades the documentation of the project.  Rave parties simulcast across the straits are as important as the discussions and software produced.  I suggest that this can be understood as developing new forms of subjectivity, in the sense given by Felix Guattari, and therefore link the fadaiat project to earlier pirate radio practices, especially Radio Alice in Bologna, Italy, in which Guattari was involved.

  20. The Strait of Gibraltar as a major biogeographic barrier in Mediterranean conifers: a comparative phylogeographic survey.

    Science.gov (United States)

    Jaramillo-Correa, J P; Grivet, D; Terrab, A; Kurt, Y; De-Lucas, A I; Wahid, N; Vendramin, G G; González-Martínez, S C

    2010-12-01

    The Strait of Gibraltar (SG) is reputed for being both a bridge and a geographic barrier to biological exchanges between Europe and Africa. Major genetic breaks associated with this strait have been identified in various taxa, but it is unknown whether these disjunctions have been produced simultaneously or by independent biogeographic processes. Here, the genetic structure of five conifers distributed on both sides of the SG was investigated using mitochondrial (nad1 b/c, nad5-1, nad5-4 and nad7-1) and chloroplast (Pt1254, Pt15169, Pt30204, Pt36480, Pt71936 and Pt87268) DNA markers. The distribution of genetic variation was partially congruent between types of markers within the same species. Across taxa, there was a significant overlapping between the SG and the genetic breaks detected, especially for the four Tertiary species surveyed (Abies pinsapo complex, Pinus nigra, Pinus pinaster and Taxus baccata). For most of these taxa, the divergence of populations across the SG could date back to long before the Pleistocene glaciations. However, their strongly different cpDNA G(ST) and R(ST) values point out that they have had dissimilar population histories, which might include contrasting amounts of pollen-driven gene flow since their initial establishment in the region. The fifth species, Pinus halepensis, was genetically depauperated and homogenous on both sides of the SG. A further analysis of nuclear DNA sequences with coalescent-based isolation with migration models suggests a Pleistocene divergence of P. halepensis populations across the SG, which is in sharp contrast with the pre-Pleistocene divergence dates obtained for P. pinaster. Altogether, these results indicate that the genetic breaks observed across this putative biogeographical barrier have been produced by independent evolutionary processes related to the biological history of each individual species instead of a common vicariant phenomenon.