The Gendered Shaping of University Leadership in Australia, South Africa and the United Kingdom

ERIC Educational Resources Information Center

White, Kate; Bagilhole, Barbara; Riordan, Sarah

2012-01-01

This article analyses career trajectories into university management in Australia, South Africa and the United Kingdom (UK), skills required to operate effectively and the power of vice-chancellors (VCs) and their impact on the gendered shaping of university leadership. It is based on qualitative research with 56 male and female senior managers.…

Petroleum system of the Gippsland Basin, Australia

USGS Publications Warehouse

Bishop, Michele G.

2000-01-01

The Gippsland Basin Province 3930, located on the southeastern coast of Australia, is formed from two successive failed rifts that developed into a passive margin during the Cretaceous. Formation of this basin is related to the break up of Gondwana, which resulted in the separation of Antarctica from Australia, and the separation of the New Zealand and Lord Howe Rise continental crust from Australia. Coals and coaly shales of Late Cretaceous through Eocene age are the source rocks for oil and gas that accumulated predominantly in anticlinal traps. The basin was Australia?s major producing basin until 1996 when daily oil/condensate production from the North West Shelf surpassed it.

Satellite Detection of Orographic Gravity-wave Activity in the Winter Subtropical Stratosphere over Australia and Africa

NASA Technical Reports Server (NTRS)

Eckermann, S. D.; Wu, D. L.

2012-01-01

Orographic gravity-wave (OGW) parameterizations in models produce waves over subtropical mountain ranges in Australia and Africa that propagate into the stratosphere during austral winter and deposit momentum, affecting weather and climate. Satellite sensors have measured stratospheric GWs for over a decade, yet find no evidence of these waves. So are parameterizations failing here? Here we argue that the short wavelengths of subtropical OGWs place them near or below the detection limits of satellite sensors. To test this hypothesis, we reanalyze nine years of stratospheric radiances from the Atmospheric Infrared Sounder (AIRS) on NASA's Aqua satellite during austral winter, applying new averaging techniques to maximize signal-to-noise and improve thresholds for OGW detection. Deep climatological enhancements in stratospheric OGW variance over specific mountain ranges in Australia and southern Africa are revealed for the first time, which exhibit temporal and vertical variations consistent with predicted OGW responses to varying background winds.

New Miocene Fossils and the History of Penguins in Australia.

PubMed

Park, Travis; Fitzgerald, Erich M G; Gallagher, Stephen J; Tomkins, Ellyn; Allan, Tony

2016-01-01

Australia has a fossil record of penguins reaching back to the Eocene, yet today is inhabited by just one breeding species, the little penguin Eudyptula minor. The description of recently collected penguin fossils from the re-dated upper Miocene Port Campbell Limestone of Portland (Victoria), in addition to reanalysis of previously described material, has allowed the Cenozoic history of penguins in Australia to be placed into a global context for the first time. Australian pre-Quaternary fossil penguins represent stem taxa phylogenetically disparate from each other and E. minor, implying multiple dispersals and extinctions. Late Eocene penguins from Australia are closest to contemporaneous taxa in Antarctica, New Zealand and South America. Given current material, the Miocene Australian fossil penguin fauna is apparently unique in harbouring 'giant penguins' after they went extinct elsewhere; and including stem taxa until at least 6 Ma, by which time crown penguins dominated elsewhere in the southern hemisphere. Separation of Australia from Antarctica during the Palaeogene, and its subsequent drift north, appears to have been a major event in Australian penguin biogeography. Increasing isolation through the Cenozoic may have limited penguin dispersal to Australia from outside the Australasian region, until intensification of the eastwards-flowing Antarctic Circumpolar Current in the mid-Miocene established a potential new dispersal vector to Australia.

Psychosocial Rehabilitation and Mental Illness: Views from Africa, India, Asia and Australia. Monograph Series, Number 49.

ERIC Educational Resources Information Center

Anthony, William A., Ed.; Wolkon, George H., Ed.

1990-01-01

This special journal "Theme" issue presents a collection of papers reflecting the psychiatric practices and community treatment for persons with severe psychiatric disabilities in Asia, Africa, Australia, and India. Some of the papers were presented at the 1988 meeting of the World Association of Psychosocial Rehabilitation (WAPR) in…

Global Scale Variation in the Salinity Sensitivity of Riverine Macroinvertebrates: Eastern Australia, France, Israel and South Africa

PubMed Central

Kefford, Ben J.; Hickey, Graeme L.; Gasith, Avital; Ben-David, Elad; Dunlop, Jason E.; Palmer, Carolyn G.; Allan, Kaylene; Choy, Satish C.; Piscart, Christophe

2012-01-01

Salinity is a key abiotic property of inland waters; it has a major influence on biotic communities and is affected by many natural and anthropogenic processes. Salinity of inland waters tends to increase with aridity, and biota of inland waters may have evolved greater salt tolerance in more arid regions. Here we compare the sensitivity of stream macroinvertebrate species to salinity from a relatively wet region in France (Lorraine and Brittany) to that in three relatively arid regions eastern Australia (Victoria, Queensland and Tasmania), South Africa (south-east of the Eastern Cape Province) and Israel using the identical experimental method in all locations. The species whose salinity tolerance was tested, were somewhat more salt tolerant in eastern Australia and South Africa than France, with those in Israel being intermediate. However, by far the greatest source of variation in species sensitivity was between taxonomic groups (Order and Class) and not between the regions. We used a Bayesian statistical model to estimate the species sensitivity distributions (SSDs) for salinity in eastern Australia and France adjusting for the assemblages of species in these regions. The assemblage in France was slightly more salinity sensitive than that in eastern Australia. We therefore suggest that regional salinity sensitivity is therefore likely to depend most on the taxonomic composition of respective macroinvertebrate assemblages. On this basis it would be possible to screen rivers globally for risk from salinisation. PMID:22567097

New Miocene Fossils and the History of Penguins in Australia

PubMed Central

Park, Travis; Fitzgerald, Erich M. G.; Gallagher, Stephen J.; Tomkins, Ellyn; Allan, Tony

2016-01-01

Australia has a fossil record of penguins reaching back to the Eocene, yet today is inhabited by just one breeding species, the little penguin Eudyptula minor. The description of recently collected penguin fossils from the re-dated upper Miocene Port Campbell Limestone of Portland (Victoria), in addition to reanalysis of previously described material, has allowed the Cenozoic history of penguins in Australia to be placed into a global context for the first time. Australian pre-Quaternary fossil penguins represent stem taxa phylogenetically disparate from each other and E. minor, implying multiple dispersals and extinctions. Late Eocene penguins from Australia are closest to contemporaneous taxa in Antarctica, New Zealand and South America. Given current material, the Miocene Australian fossil penguin fauna is apparently unique in harbouring ‘giant penguins’ after they went extinct elsewhere; and including stem taxa until at least 6 Ma, by which time crown penguins dominated elsewhere in the southern hemisphere. Separation of Australia from Antarctica during the Palaeogene, and its subsequent drift north, appears to have been a major event in Australian penguin biogeography. Increasing isolation through the Cenozoic may have limited penguin dispersal to Australia from outside the Australasian region, until intensification of the eastwards-flowing Antarctic Circumpolar Current in the mid-Miocene established a potential new dispersal vector to Australia. PMID:27115739

New Exploration of North Kerguelen Plateau Margins : Constraints for the Australia-Antarctica Separation

NASA Astrophysics Data System (ADS)

Courrèges, E.; Vially, R.; Roest, W. R.; Patriat, M.; Patriat, P.; Loubrieu, B.; Lecomte, J.-C.; Schaming, M.; Schmitz, J.; Maia, M.

2009-04-01

at a key period (Oligocene), helps us understand the setting up of the oceanic plateau and the kinematics reconstructions between Antarctica and Australia plates. We focused on the northeastern margin of the Kerguelen Plateau, from 77E30 up to the Amsterdam Saint-Paul fracture zone, where the South East Indian Ridge (SEIR) shows a large offset toward the Kerguelen Plateau. On a larger scale, the opening between Kerguelen Plateau and Broken Ridge has kept very morphologically homologous margins on each side of the SEIR: in the Southern Kerguelen Plateau, the magnetic anomalies are regular, parallel to the SEIR and also to the morphological boundary of the plateau. In contrast, the northeastern margin of the Northern Kerguelen Plateau is not much explored and its interpretation less obvious, because volcanic masses overlie discordantly the oceanic crust. We compiled the magnetic anomalies pickings, integrating data from recent Kergueplac surveys and previous studies, to identify with more confidence the oldest anomalies at the plateau margin. We used it for reconstructions at different stages (from a8o to initial opening), realised with rotation poles of Cande & Stocks (2004). These reconstructions confirm that kinematic in the whole SE Indian Ocean, and in particular in the Northern part of the Kerguelen Plateau, remains unresolved. In particular, we discuss both the fit between Kerguelen and Broken Ridge and the implication for the opening between Australia and Antarctica as well as the possible junctions along the Amsterdam fracture zone with the Crozet basin where the spreading rate was much faster before A18.

Maternity health care: The experiences of Sub-Saharan African women in Sub-Saharan Africa and Australia.

PubMed

Mohale, Hlengiwe; Sweet, Linda; Graham, Kristen

2017-08-01

Increasing global migration is resulting in a culturally diverse population in the receiving countries. In Australia, it is estimated that at least four thousand Sub-Saharan African women give birth each year. To respond appropriately to the needs of these women, it is important to understand their experiences of maternity care. The study aimed to examine the maternity experiences of Sub-Saharan African women who had given birth in both Sub-Saharan Africa and in Australia. Using a qualitative approach, 14 semi-structured interviews with Sub-Saharan African women now living in Australia were conducted. Data was analysed using Braun and Clark's approach to thematic analysis. Four themes were identified; access to services including health education; birth environment and support; pain management; and perceptions of care. The participants experienced issues with access to maternity care whether they were located in Sub-Saharan Africa or Australia. The study draws on an existing conceptual framework on access to care to discuss the findings on how these women experienced maternity care. The study provides an understanding of Sub-Saharan African women's experiences of maternity care across countries. The findings indicate that these women have maternity health needs shaped by their sociocultural norms and beliefs related to pregnancy and childbirth. It is therefore arguable that enhancing maternity care can be achieved by improving women's health literacy through health education, having an affordable health care system, providing respectful and high quality midwifery care, using effective communication, and showing cultural sensitivity including family support for labouring women. Copyright © 2016 Australian College of Midwives. Published by Elsevier Ltd. All rights reserved.

Compositions of Three Lunar Meteorites: Meteorite Hills 01210, Northeast Africa 001, and Northwest Africa 3136

NASA Technical Reports Server (NTRS)

Korotev, R. L.; Irving, A. J.

2005-01-01

We report on compositions obtained by instrumental neutron activation analysis on three new lunar meteorites, MET 01210 (Meteorite Hills, Antarctica; 23 g), NEA 001 (Northeast Africa, Sudan; 262 g), and NWA 3136 (Northwest Africa, Algeria or Morocco; 95 g). As in previous similar studies, we divided our samples into many (8-9) small (approximately 30 mg) subsamples prior to analysis.

Episodic behavior of Gondwanide deformation in eastern Australia: Insights from the Gympie Terrane

NASA Astrophysics Data System (ADS)

Hoy, Derek; Rosenbaum, Gideon

2017-08-01

The mechanisms that drove Permian-Triassic orogenesis in Australia and throughout the Cordilleran-type Gondwanan margin is a subject of debate. Here we present field-based results on the structural evolution of the Gympie Terrane (eastern Australia), with the aim of evaluating its possible role in triggering widespread orogenesis. We document several deformation events (D1-D3) in the Gympie Terrane and show that the earliest deformation, D1, occurred only during the final pulse of orogenesis (235-230 Ma) within the broader Gondwanide Orogeny. In addition, we found no evidence for a crustal suture, suggesting that terrane accretion was not the main mechanism behind deformation. Rather, the similar spatiotemporal evolution of Permian-Triassic orogenic belts in Australia, Antarctica, South Africa, and South America suggest that the Gondwanide Orogeny was more likely linked to large-scale tectonic processes such as plate reorganization. In the context of previous work, our results highlight a number of spatial and temporal variations in pulses of deformation in eastern Australia, suggesting that shorter cycles of deformation occurred at a regional scale within the broader episode of the Gondwanide Orogeny. Similarly to the Cenozoic evolution of the central and southern Andes, we suggest that plate coupling and orogenic cycles in the Late Paleozoic to Early Mesozoic Gondwanide Orogeny have resulted from the superposition of mechanisms acting at a range of scales, perhaps contributing to the observed variations in the intensity, timing, and duration of deformation phases within the orogenic belt.

GRACE Gravity Data Target Possible Mega-impact in North Central Wilkes Land, Antarctica

NASA Technical Reports Server (NTRS)

vonFrese, Ralph R. B.; Wells, Stuart B.; Potts. Laramie V.; Gaya-Pique, Luis R.; Golynsky, Alexander V.; Hernandez, Orlando; Kim, Jeong Woo; Kim, Hyung Rae; Hwang, Jong Sun; Taylor, Patrick T.

2005-01-01

A prominent positive GRACE satellite-measured free-air gravity anomaly over regionally depressed subglacial topography may identify a mascon centered on (70 deg S, 120 deg E) between the Gamburtsev and Transantarctic Mountains of East Antarctica. Being more than twice the size of the Chicxulub crater, the inferred Wilkes Land impact crater is a strong candidate for a Gondwana source of the greatest extinction of life at the end of the Permian. Its ring structure intersects the coastline and thus may have strongly influenced the Cenozoic rifting of East Antarctica from Australia that resulted in the enigmatic lack of crustal thinning on the conjugate Australian block.

The significance of Antarctica for studies of global geodynamics

USGS Publications Warehouse

Sutherland, R.

2007-01-01

Antarctica has geometric significance for global plate kinematic studies, because it links seafloor spreading systems of the African hemisphere (Indian and Atlantic Oceans) with those of the Pacific. Inferences of plate motions back to 44 Ma, around the onset of rapid spreading south of Australia and formation of a new boundary through New Zealand, are consistent with Antarctic rifting and formation of the Adare Basin during 44-26 Ma (i.e., no additional plate motions are required in the South Pacific). The time period 52-44 Ma represents a profound global and South Pacific tectonic change, and significant details remain unresolved. For 74 Ma a significant nonclosure of the South Pacific plate-motion circuit is identified if Antarctic motion is not included. Alternate inferences of motion through Antarctica during the interval 74-44 Ma imply significantly different subduction volumes and directions around the Pacific, and imply different relative motions between hotspots

IFLA General Conference 1988. Division of Regional Activities. Sections on: Asia and Oceania; Africa; Latin America and the Caribbean; Australia.

ERIC Educational Resources Information Center

International Federation of Library Associations, The Hague (Netherlands).

The eight papers in this collection focus on library activities in various geographical regions, e.g., Asia, Oceania, Africa, Latin America, the Caribbean, and Western Australia: (1) "Future Approaches and Prospects of Computerised Information Network among the Countries of South Asian Association for Regional Cooperation (SAARC)" (Abdullah…

Assessment of the Risk of Ebola Importation to Australia

PubMed Central

Cope, Robert C.; Cassey, Phillip; Hugo, Graeme J.; Ross, Joshua V.

2014-01-01

Objectives: To assess the risk of Ebola importation to Australia during the first six months of 2015, based upon the current outbreak in West Africa. Methodology: We assessed the risk under two distinct scenarios: (i) assuming that significant numbers of cases of Ebola remain confined to Guinea, Liberia and Sierra Leone, and using historic passenger arrival data into Australia; and, (ii) assuming potential secondary spread based upon international flight data. A model appropriate to each scenario is developed, and parameterised using passenger arrival card or international flight data, and World Health Organisation case data from West Africa. These models were constructed based on WHO Ebola outbreak data as at 17 October 2014 and 3 December 2014. An assessment of the risk under each scenario is reported. On 27 October 2014 the Australian Government announced a policy change, that visas from affected countries would be refused/cancelled, and the predicted effect of this policy change is reported. Results: The current probability of at least one case entering Australia by 1 July 2015, having travelled directly from West Africa with historic passenger arrival rates into Australia, is 0.34. Under the new Australian Government policy of restricting visas from affected countries (as of 27 October 2014), the probability of at least one case entering Australia by 1 July 2015 is reduced to 0.16. The probability of at least one case entering Australia by 1 July 2015 via an outbreak from a secondary source country is approximately 0.12. Conclusions: Our models suggest that if the transmission of Ebola remains unchanged, it is possible that a case will enter Australia within the first six months of 2015, either directly from West Africa (even when current visa restrictions are considered), or via secondary outbreaks elsewhere. Government and medical authorities should be prepared to respond to this eventuality. Control measures within West Africa over recent months have

Seismicity of the Earth 1900–2010 Australia plate and vicinity

USGS Publications Warehouse

Benz, Harley M.; Herman, Matthew; Tarr, Arthur C.; Hayes, Gavin P.; Furlong, Kevin P.; Villaseñor, Antonio; Dart, Richard L.; Rhea, Susan

2011-01-01

This map shows details of the Australia plate and vicinity not presented in Tarr and others (2010). The boundary of the Australia plate includes all fundamental plate boundary components: mid-ocean ridges, subduction zones, arc-continent collisions, and large-offset transform faults. Along the southern edge of the plate the mid-ocean ridge separates the Australia and Antarctica plates and its behavior is straightforward. In contrast, the other boundary segments that ring the Australia plate represent some of the most seismically active elements of the global plate boundary system, and some of the most rapidly evolving plate interactions. As a result, there are some very complex structures which host many large and great earthquakes

Polyphase Neoproterozoic orogenesis within the east Africa- Antarctica orogenic belt in central and northern Madagascar

USGS Publications Warehouse

Key, R.M.; Pitfield, P.E.J.; Thomas, Ronald J.; Goodenough, K.M.; Waele, D.; Schofield, D.I.; Bauer, W.; Horstwood, M.S.A.; Styles, M.T.; Conrad, J.; Encarnacion, J.; Lidke, D.J.; O'connor, E. A.; Potter, C.; Smith, R.A.; Walsh, G.J.; Ralison, A.V.; Randriamananjara, T.; Rafahatelo, J.-M.; Rabarimanana, M.

2011-01-01

Our recent geological survey of the basement of central and northern Madagascar allowed us to re-evaluate the evolution of this part of the East Africa-Antarctica Orogen (EAAO). Five crustal domains are recognized, characterized by distinctive lithologies and histories of sedimentation, magmatism, deformation and metamorphism, and separated by tectonic and/or unconformable contacts. Four consist largely of Archaean metamorphic rocks (Antongil, Masora and Antananarivo Cratons, Tsaratanana Complex). The fifth (Bemarivo Belt) comprises Proterozoic meta-igneous rocks. The older rocks were intruded by plutonic suites at c. 1000 Ma, 820-760 Ma, 630-595 Ma and 560-520 Ma. The evolution of the four Archaean domains and their boundaries remains contentious, with two end-member interpretations evaluated: (1) all five crustal domains are separate tectonic elements, juxtaposed along Neoproterozoic sutures and (2) the four Archaean domains are segments of an older Archaean craton, which was sutured against the Bemarivo Belt in the Neoproterozoic. Rodinia fragmented during the early Neoproterozoic with intracratonic rifts that sometimes developed into oceanic basins. Subsequent Mid- Neoproterozoic collision of smaller cratonic blocks was followed by renewed extension and magmatism. The global 'Terminal Pan-African' event (560-490 Ma) finally stitched together the Mid-Neoproterozoic cratons to form Gondwana. ?? The Geological Society of London 2011.

Crustal structure and evolution of the Mawson Sea, western Wilkes Land margin, East Antarctica

USGS Publications Warehouse

Leitchenkov, G.L.; Gandyukhin, V.V.; Guseva, Yu. B.; Kazankov, A. Yu

2007-01-01

3 to 11 mm/yr. Three major unconformities are identified in the sedimentary cover of the Mawson Sea and are interpreted to be caused by break-up between Australia and Antarctica at about 81 Ma ago (WL1), the first arrival of the ice sheet to the Mawson Sea (WL3) and continental scale glaciation at about 34 Ma ago (WL4).

New constraints on the Neogene plate kinematics of West and East Antarctica

NASA Astrophysics Data System (ADS)

Granot, R.; Dyment, J.; Szitkar, F.

2016-12-01

The motion between East and West Antarctic Plates during the last 26 million years (post-Adare seafloor spreading) is loosely constrained, and although it is often considered negligible, accumulating observations from along the rift system suggest that significant faulting and transtensional motion have occurred in that period. Part of the reason for this uncertainty is the complicated kinematic evolution of the oceanic crust found north of the Ross Sea and the lack of proper magnetic anomaly data at key tectonic locations. We have conducted a series of two cruises (TACT project) aboard M/V L'Astrolabe, the supply ship of Dumont d'Urville French Antarctic station, in February-March of 2012 and 2016 during which we have acquired total field magnetic profiles oriented along flowline direction and straddling the Tasman spreading corridor, located between Tasmania and the Balleny Islands and the Tasman and Balleny FZs. The new data allow us to refine the overall motion of the Macquarie Plate relative to Australia. After correction of this motion, the Tasman corridor, lying west of the Balleny FZ uncovers the Australia-East Antarctic plate motion, and the Balleny corridor, lying east of the FZ uncovers the Australia-West Antarctic plate motion, reveal a mismatched anomaly pattern that result from the Neogene relative plate motion between East and West Antarctica. We combine these new observations together with geological constraints from within the west Antarctic rift system to compute new rotation parameters that describe the relative plate motion between West and East Antarctica for the last 26 million years.

A North American and global survey of perfluoroalkyl substances in surface soils: Distribution patterns and mode of occurrence

EPA Science Inventory

The distribution of 32 per/polyfluoroalkyl substances (PFASs) in surface soils was determined at 62 locations representing all continents (North America n = 33, Europe n = 10, Asia n = 6, Africa n = 5, Australia n = 4, South America n = 3 and Antarctica n = 1) using ultra perform...

Classroom Antarctica

ERIC Educational Resources Information Center

Gozzard, David

2017-01-01

Australian company Antarctica Flights runs summer sightseeing trips out of Australian capital cities to tour the Antarctic coast. The Laby Foundation of the University of Melbourne, through its "Classroom Antarctica" program, sponsored Kent Street High School science teacher, Ms Suzy Urbaniak and 18 of her students to take the trip, to…

Before the freeze: otoliths from the Eocene of Seymour Island, Antarctica, reveal dominance of gadiform fishes (Teleostei)

PubMed Central

Schwarzhans, Werner; Mörs, Thomas; Engelbrecht, Andrea; Reguero, Marcelo; Kriwet, Jürgen

2017-01-01

The first record of fossil teleostean otoliths from Antarctica is reported. The fossils were obtained from late Early Eocene shell beds of the La Meseta Formation, Seymour Island that represent the last temperate marine climate phase in Antarctica prior to the onset of cooling and subsequent glaciation during the late Eocene. A total of 17 otolith-based teleost taxa are recognized, with 10 being identifiable to species level containing nine new species and one new genus: Argentina antarctica sp. nov., Diaphus? marambionis sp. nov., Macruronus eastmani sp. nov., Coelorinchus balushkini sp. nov., Coelorinchus nordenskjoeldi sp. nov., Palimphemus seymourensis sp. nov., Hoplobrotula? antipoda sp. nov., Notoberyx cionei gen. et sp. nov. and Cepola anderssoni sp. nov. Macruronus eastmani sp. nov. is also known from the late Eocene of Southern Australia, and Tripterophycis immutatus Schwarzhans, widespread in the southern oceans during the Eocene, has been recorded from New Zealand, southern Australia, and now Antarctica. The otolith assemblage shows a typical composition of temperate fishes dominated by gadiforms, very similar at genus and family levels to associations known from middle Eocene strata of New Zealand and the late Eocene of southern Australia, but also to the temperate Northern Hemisphere associations from the Paleocene of Denmark. The Seymour Island fauna bridges a gap in the record of global temperate marine teleost faunas during the early Eocene climate maximum. The dominant gadiforms are interpreted as the main temperate faunal component, as in the Paleocene of Denmark. Here they are represented by the families Moridae, Merlucciidae (Macruroninae), Macrouridae and Gadidae. Nowadays Gadidae are a chiefly Northern Hemisphere temperate family. Moridae, Macruroninae and Macrouridae live today on the lower shelf to deep-water or mesopelagically with Macruroninae being restricted to the Southern Ocean. The extant endemic Antarctic gadiform family

Before the freeze: otoliths from the Eocene of Seymour Island, Antarctica, reveal dominance of gadiform fishes (Teleostei).

PubMed

Schwarzhans, Werner; Mörs, Thomas; Engelbrecht, Andrea; Reguero, Marcelo; Kriwet, Jürgen

2017-01-01

The first record of fossil teleostean otoliths from Antarctica is reported. The fossils were obtained from late Early Eocene shell beds of the La Meseta Formation, Seymour Island that represent the last temperate marine climate phase in Antarctica prior to the onset of cooling and subsequent glaciation during the late Eocene. A total of 17 otolith-based teleost taxa are recognized, with 10 being identifiable to species level containing nine new species and one new genus: Argentina antarctica sp. nov., Diaphus? marambionis sp. nov., Macruronus eastmani sp. nov., Coelorinchus balushkini sp. nov., Coelorinchus nordenskjoeldi sp. nov., Palimphemus seymourensis sp. nov., Hoplobrotula? antipoda sp. nov., Notoberyx cionei gen. et sp. nov. and Cepola anderssoni sp. nov. Macruronus eastmani sp. nov. is also known from the late Eocene of Southern Australia, and Tripterophycis immutatus Schwarzhans, widespread in the southern oceans during the Eocene, has been recorded from New Zealand, southern Australia, and now Antarctica. The otolith assemblage shows a typical composition of temperate fishes dominated by gadiforms, very similar at genus and family levels to associations known from middle Eocene strata of New Zealand and the late Eocene of southern Australia, but also to the temperate Northern Hemisphere associations from the Paleocene of Denmark. The Seymour Island fauna bridges a gap in the record of global temperate marine teleost faunas during the early Eocene climate maximum. The dominant gadiforms are interpreted as the main temperate faunal component, as in the Paleocene of Denmark. Here they are represented by the families Moridae, Merlucciidae (Macruroninae), Macrouridae and Gadidae. Nowadays Gadidae are a chiefly Northern Hemisphere temperate family. Moridae, Macruroninae and Macrouridae live today on the lower shelf to deep-water or mesopelagically with Macruroninae being restricted to the Southern Ocean. The extant endemic Antarctic gadiform family

A New Absolute Plate Motion Model for Africa

NASA Astrophysics Data System (ADS)

Maher, S. M.; Wessel, P.; Müller, D.; Harada, Y.

2013-12-01

The India-Eurasia collision, a change in relative plate motion between Australia and Antarctica, and the coeval ages of the Hawaiian Emperor Bend (HEB) and Louisville Bend of ~Chron 22-21 all provide convincing evidence of a global tectonic plate reorganization at ~50 Ma. Yet if it were a truly global event, then there should be a contemporaneous change in Africa absolute plate motion (APM) reflected by physical evidence somewhere on the Africa plate. This evidence might be visible in the Reunion-Mascarene bend, which exhibits many HEB-like features such as a large angular change close to ~50 Ma. Recently, the Reunion hotpot trail has been interpreted as a continental feature with incidental hotspot volcanism. Here we propose the alternative hypothesis that the northern portion of the chain between Saya de Malha and the Seychelles (Mascarene Plateau) formed as the Reunion hotspot was situated on the Carlsberg Ridge, contemporaneously forming the Chagos-Laccadive Ridge on the India plate. We have created a 4-stage model that explores how a simple APM model fitting the Mascarene Plateau can also satisfy the age progressions and geometry of other hotspot trails on the Africa plate. This type of model could explain the apparent bifurcation of the Tristan hotspot chain, the age reversals seen along the Walvis Ridge and the diffuse nature of the St. Helena chain. To test this hypothesis we have made a new African APM model that goes back to ~80 Ma using a modified version of the Hybrid Polygonal Finite Rotation Method. This method uses seamount chains and their associated hotspots as geometric constraints for the model, and seamount age dates to determine its motion through time. The positions of the hotspots can be moved to get the best fit for the model and to explore the possibility that the ~50 Ma bend in the Reunion-Mascarene chain reflects Africa plate motion. We will examine how well this model can predict the key features reflecting Africa plate motion and

Lost Continents? Children's Understanding of the Location and Orientation of the Earth's Land Masses.

ERIC Educational Resources Information Center

Wiegand, Patrick; Stiell, Bernadette

1996-01-01

Presents the results of an experiment that asked 53 middle school children to identify continent shapes and to arrange them to form a map of the world. Australia, Europe, and Asia were the most recognized. Misidentified and misaligned most consistently were Africa and Antarctica. Discusses possible reasons and teachers' responses. (MJP)

Mineralogical maturity in dunefields of North America, Africa and Australia

USGS Publications Warehouse

Muhs, D.R.

2004-01-01

Studies of dunefields in central and western North America show that mineralogical maturity can provide new insights into the origin and evolution of aeolian sand bodies. Many of the world's great sand seas in Africa, Asia and Australia are quartz-dominated and thus can be considered to be mineralogically mature. The Algodones (California) and Parker (Arizona) dunes in the southwestern United States are also mature, but have inherited a high degree of mineralogical maturity from quartz-rich sedimentary rocks drained by the Colorado River. In Libya, sediments of the Zallaf sand sea, which are almost pure quartz, may have originated in a similar fashion. The Fort Morgan (Colorado) and Casper (Wyoming) dunefields in the central Great Plains of North America, and the Namib sand sea of southern Africa have an intermediate degree of mineralogical maturity because their sources are large rivers that drained both unweathered plutonic and metamorphic rocks and mature sedimentary rocks. Mojave Desert dunefields in the southwestern United States are quite immature because they are in basins adjacent to plutonic rocks that were their sources. Other dunefields in the Great Plains of North America (those in Nebraska and Texas) are more mature than any possible source sediments and therefore reflect mineralogical evolution over time. Such changes in composition can occur because of either of two opposing long-term states of the dunefield. In one state, dunes are stable for long periods of time and chemical weathering depletes feldspars and other weatherable minerals in the sediment body. In the other state, which is most likely for the Great Plains, abrasion and ballistic impacts deplete the carbonate minerals and feldspars because the dunes are active for longer periods than they are stable. ?? 2003 Elsevier B.V. All rights reserved.

The Cambrian Ross Orogeny in northern Victoria Land (Antarctica) and New Zealand: A synthesis

USGS Publications Warehouse

Federico, L.; Capponi, G.; Crispini, L.; Bradshaw, J.D.

2007-01-01

In the Cambrian, the paleo-Pacific margin of the Gondwana supercontinent included East Antarctica, Australia, Tasmania and New Zealand and was affected by themajor Ross-Delamerian Orogeny. In Antarctica, evidence suggests that this resulted from oblique subduction and that in northern Victoria Land it was accompanied by the opening and subsequent closure of a back-arc basin. Comparison of the type and timing of sedimentary, magmatic and metamorphic events in areas noted above shows strong similarities between northern Victoria Land and New Zealand. In both regions Middle Cambrian volcanites are interpreted as arc/back-arc assemblages produced by west-directed subduction; sediments interbedded with the volcanites show provenance both from the arc and from the Gondwana margin and therefore place the basin close to the continent. Back-arc closure in the Late Cambrian was likely accomplished through a second subduction system

Serum proteins in the leopard seal, Hydrurga leptonyx, in Prydz Bay, Eastern Antarctica and the coast of NSW, Australia.

PubMed

Gray, Rachael; Canfield, Paul; Rogers, Tracey

2005-09-01

Blood protein analysis including total serum protein and albumin by chemical methods, fibrinogen estimation and serum protein electrophoresis (SPE) was performed on the leopard seal, Hydrurga leptonyx. The most commonly observed SPE pattern was eight fractions designated albumin, alpha(1a), alpha(1b), alpha(2a), alpha(2b), beta(1), beta(2) and gamma-globulin. Significantly higher total serum protein and albumin concentrations, as determined by chemical methods, and significantly higher alpha(2)-globulin concentrations, determined by SPE, were seen in free-ranging male seals compared to females, whilst significantly higher beta-globulin concentrations were seen in female seals. Season of sampling influenced fibrinogen and beta(2)-globulin concentrations, whereas there were no significant differences in any protein concentrations with moult status. Qualitative comparison of SPE traces of leopard seals in Antarctica with "sick" individuals in NSW, Australia revealed obvious differences, as did quantitative comparison of protein concentrations where differences in alpha(1), alpha(2), beta(1), beta(2), and gamma-globulin concentrations were seen. These findings suggest that SPE is a useful tool for investigating serum proteins in the leopard seal, with applications for the investigation of "sick" individuals and the assessment of variation in homeostasis. This technique could also be used to identify the presence of environmental stressors, subclinical disease and physiological variation within specific seal populations.

Mantle dynamics of continent-wide tilting of Australia

NASA Astrophysics Data System (ADS)

Dicaprio, L.; Gurnis, M.; Muller, R. D.

2009-12-01

Australia is distinctive in that during the Cenozoic it experienced first order, broad-scale vertical motions unrelated to normal orogenic processes. The progressive continent-wide tilting down to the northeast is attributed to the horizontal motion of the continent over subducted slabs. We use plate tectonic reconstructions and a model of mantle convection to quantitatively link the geological evolution of the continent to mantle convection. The passage of slabs beneath the Southwest Pacific since 50 Ma is modeled numerically, and the results are compared to geologic observations of anomalous topography. Models show that Australia undergoes a 300 m northeast downward tilt as it approaches and overrides subducted slabs between Melanesia and the active margin along the Loyalty and proto-Tonga Kermadec subduction systems. This pattern of dynamic subsidence is consistent with observations of continent wide tilting and may indicate that during the Cenozoic Australia moved northward away from a relatively hot mantle anomaly presently located beneath Antarctica.

Intergenerational differences in acculturation experiences, food beliefs and perceived health risks among refugees from the Horn of Africa in Melbourne, Australia.

PubMed

Wilson, Alyce; Renzaho, Andre

2015-01-01

To investigate the differences in acculturation experiences between parent and adolescent refugees from the Horn of Africa in Melbourne, Australia and to explore food beliefs and perceived health risks from an intergenerational perspective. Qualitative cross-sectional study involving a combination of semi-structured one-on-one interviews and focus group discussions. North-West suburbs of Melbourne, Australia. Eritrean, Ethiopian, Somali and Sudanese refugees. Using a purposeful sampling technique, twelve semi-structured face-to-face interviews (nine adults and three adolescents) and four in-depth focus groups (two with adolescents each containing six participants and two with adults one containing six participants and the other ten participants) were carried out. Thus overall data were obtained on fifteen adolescents and twenty-five parents. Qualitative analysis identified differences between parents and adolescents in relation to lifestyle, diet and physical activity. Views regarding health consequences of their changed diets also differed. Parental feeding practices encompassed a variety of methods and were enforced in an attempt by parents to control their children's dietary behaviours and prevent their drift away from traditional eating habits. These findings call for more research to contextualise dietary acculturation among refugee youth and the impact of migration on parenting styles and feeding practices in communities from the Horn of Africa. Preventive health programmes with Horn of Africa refugees need to acknowledge the effect of acculturation on diet and physical activity levels and a socio-cultural framework needs to be developed with respect to the importance and influence of the family environment.

Antarctica and global paleogeography: from Rodinia, rhrough Gondwanaland and Pangea, to the birth of the Southern Ocean and the opening of gateways

USGS Publications Warehouse

Torsvik, T.H.; Gaina, C.; Redfield, T.F.

2007-01-01

Neoproterozoic Rodinia reconstructions associate East Antarctica (EANT) with cratonic Western Australia. By further linking EANT to both Gondwana and Pangea with relative plate circuits, a Synthetic Apparent Polar Wander (SAPW) path for EANT is calculated. This path predicts that EANT was located at tropical to subtropical southerly latitudes from ca. 1 Ga to 420 Ma. Around 400 Ma and again at 320 Ma, EANT underwent southward drift. Ca. 250 Ma Antarctica voyaged briefly north but headed south again ca. 200 Ma. Since 75 Ma EANT became surrounded by spreading centers and has remained extremely stable. Although paleomagnetic data of the blocks that embrace West Antarctica are sparse, we attempt to model their complex kinematics since the Mesozoic. Together with the SAPW path and a revised circum-Antarctic seafloor spreading history we construct a series of new paleogeographic maps.

Tectonic elements of the continental margin of East Antarctica, 38-164ºE

USGS Publications Warehouse

O'Brien, P.E.; Stagg, H.M.J.

2007-01-01

The East Antarctic continental margin from 38–164ºE is divided into western and eastern provinces that developed during the separation of India from Australia–Antarctica (Early Cretaceous) and Australia from Antarctica (Late Cretaceous). In the overlap between these provinces the geology is complex and bears the imprint of both extension/spreading episodes, with an overprinting of volcanism. The main rift-bounding faults appear to approximately coincide with the outer edge of the continental shelf. Inboard of these faults, the sedimentary cover thins above shallowing basement towards the coast where crystalline basement generally crops out. The continental slope and the landward flanks of the ocean basins, are blanketed by up to 9–10 km of mainly post-rift sediments in margin-parallel basins, except in the Bruce Rise area. Beneath this blanket, extensive rift basins are identified off Enderby and Wilkes Land/Terre Adélie; however, their extent and detailed structures are difficult to determine.

Bringing Antarctica Home

ERIC Educational Resources Information Center

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…

Phytoplankton bloom in Spencer Gulf, South Australia

NASA Technical Reports Server (NTRS)

2002-01-01

Summer in southern Australia is the dry season, and in this true-color MODIS image of South Australia and the Spencer Gulf from October 20,2001, the area's vegetation is losing much of the lushness it possessed in the winter rainy season (See image from September 19, 2001). In southern hemisphere summer, the high pressure systems that dominate the continent's weather move south, and block the rain-bearing westerly winds. The resulting changes in seasonal rainfall are extreme. Many of the rivers are impermanent, and flow into dry or impermanent salt lakes, such as Lake Torrens (long, thin lake bed, roughly in the center of the image), and Lake Eyre (pink and white lake bed to the northwest of Torrens). Between the Eyre Peninsula (lower left) and the Yorke Peninsula further east lies the Spencer Gulf, showing the blue-green swirls that indicate a phytoplankton bloom. Australia gets less rainfall than any continent except Antarctica, and the low and seasonal flows contribute to problems with salinity and algal blooms in the continent's surface waters.

Antarctica Day: An International Celebration

NASA Astrophysics Data System (ADS)

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

Living and Working in Antarctica.

ERIC Educational Resources Information Center

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…

Geoscience Australia Continuous Global Positioning System (CGPS) Station Field Campaign Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ruddick, R.; Twilley, B.

2016-03-01

This station formed part of the Australian Regional GPS Network (ARGN) and South Pacific Regional GPS Network (SPRGN), which is a network of continuous GPS stations operating within Australia and its Territories (including Antarctica) and the Pacific. These networks support a number of different science applications including maintenance of the Geospatial Reference Frame, both national and international, continental and tectonic plate motions, sea level rise, and global warming.

History and management of sirex wood wasp in Australia

Treesearch

Angus J. Carnegie

2007-01-01

This paper reviews the history and management of Sirex noctilio in Australia, including information from previous reviews as well as more recent data. The sirex wood wasp, Sirex noctilio, is one of the most important insect pests of Pinus radiata in Australia. Native to Europe, North Africa and Turkey, S...

Informal STEM Education in Antarctica

NASA Astrophysics Data System (ADS)

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.

Cenozoic motion between East and West Antarctica

PubMed

Cande; Stock; Muller; Ishihara

2000-03-09

The West Antarctic rift system is the result of late Mesozoic and Cenozoic extension between East and West Antarctica, and represents one of the largest active continental rift systems on Earth. But the timing and magnitude of the plate motions leading to the development of this rift system remain poorly known, because of a lack of magnetic anomaly and fracture zone constraints on seafloor spreading. Here we report on magnetic data, gravity data and swath bathymetry collected in several areas of the south Tasman Sea and northern Ross Sea. These results enable us to calculate mid-Cenozoic rotation parameters for East and West Antarctica. These rotations show that there was roughly 180 km of separation in the western Ross Sea embayment in Eocene and Oligocene time. This episode of extension provides a tectonic setting for several significant Cenozoic tectonic events in the Ross Sea embayment including the uplift of the Transantarctic Mountains and the deposition of large thicknesses of Oligocene sediments. Inclusion of this East-West Antarctic motion in the plate circuit linking the Australia, Antarctic and Pacific plates removes a puzzling gap between the Lord Howe rise and Campbell plateau found in previous early Tertiary reconstructions of the New Zealand region. Determination of this East-West Antarctic motion also resolves a long standing controversy regarding the contribution of deformation in this region to the global plate circuit linking the Pacific to the rest of the world.

Tectonics of Antarctica

USGS Publications Warehouse

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

A Review of Marine Geophysical Constraints on the Motion Between East and West Antarctica in the Cenozoic (Invited)

NASA Astrophysics Data System (ADS)

Cande, S. C.; Stock, J. M.

2010-12-01

Motion between East and West Antarctica in the Late Cretaceous and Cenozoic is derived by summing the plate circuit(s) linking East Antarctica to Australia to the Lord Howe Rise to the Pacific plate to West Antarctica (the Aus-Pac plate circuit). We discuss this motion in two parts: motion before and after 42 Ma. For the younger time interval, motion is directly constrained by magnetic anomalies in the Adare Basin, which opened by ultraslow seafloor spreading between 42 and 26 Ma (anomalies 18 to 9). The Adare Basin magnetic anomaly constraints can be combined with magnetic anomaly and fracture zone data from the SEIR (Aus-East Ant to the west of the Balleny FZ and Aus - West Ant to the east) to set up an Aus-East Ant - West Ant three-plate problem. The original solution of this three-plate configuration (Cande et al., 2000) only had data from a very short section of the Adare Basin and obtained an answer with very large uncertainties on the East-West Ant rotation. Better estimates of the East-West Ant rotation have been calculated by adding constraints based on seismically controlled estimates of extension in the Victoria Land Basin (Davey et al., 2006) and constraints from Damaske et al’s (2007) detailed aeromagnetic survey of the Adare Basin and adjacent Northern Basin (Granot et al., 2010). Currently, we are working on improving the accuracy of rotations for the post-42 Ma time interval by taking advantage of an unusual plate geometry that enables us to solve a five-boundary, four-plate configuration. Specifically, motion between the four plates (East Ant, West Ant, Aus and Pac) encompasses two related triple junction systems with five spreading ridge segments (Aus-East Ant, Aus-West Ant, Aus-Pac, Pac-West Ant and East Ant-West Ant) which can be combined and solved simultaneously. For the older, pre-42 Ma time interval, the only way to calculate motion between East and West Antarctica is via the long Aus-Pac plate circuit (although it is possible that

Antarctica

Atmospheric Science Data Center

2013-04-16

article title:  Twilight in Antarctica     View larger JPEG ... SpectroRadiometer (MISR) instrument on board Terra. The Ross Ice Shelf and Transantarctic Mountains are illuminated by low Sun. MISR was ...

Pulsating star research from Antarctica

NASA Astrophysics Data System (ADS)

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.

Sounding rockets in Antarctica

NASA Technical Reports Server (NTRS)

Alford, G. C.; Cooper, G. W.; Peterson, N. E.

1982-01-01

Sounding rockets are versatile tools for scientists studying the atmospheric region which is located above balloon altitudes but below orbital satellite altitudes. Three NASA Nike-Tomahawk sounding rockets were launched from Siple Station in Antarctica in an upper atmosphere physics experiment in the austral summer of 1980-81. The 110 kg payloads were carried to 200 km apogee altitudes in a coordinated project with Arcas rocket payloads and instrumented balloons. This Siple Station Expedition demonstrated the feasibility of launching large, near 1,000 kg, rocket systems from research stations in Antarctica. The remoteness of research stations in Antarctica and the severe environment are major considerations in planning rocket launching expeditions.

Strategies for Reforming University/State Relationships: Australia's Experience Sets Examples.

ERIC Educational Resources Information Center

McGuire, Harriet C.

1997-01-01

The World Bank's recommendations for higher education policy in Africa offer an appropriate framework for comparison with recent educational policy changes in Australia, particularly in the area of university financing. Australia provides a case study of how national policies have had a dramatic and rapid effect on education and have quickly…

A new French-Italian geomagnetic observatory in Dome C, Antarctica

NASA Astrophysics Data System (ADS)

Cafarella, L.; Zirizzotti, A.; di Mauro, D.; Schott, J. J.; Pèrès, A.; Cantin, J. M.

2003-04-01

Concordia is a scientific station located in the inner part of Antarctica (latitude 75° 06' S, longitude 123° 23' E, at about 3,200 m above sea level), about 950 km away from the coast. Near by the station a permanent Base is under construction and is expected to open in the year 2004. All this is the result of a join French Italian Antarctic Programs (IFRTP and PNRA respectively) effort to provide support to a growing number of scientific researches. The station is located 1.200 from Terra Nova Bay (Italy), 560 km away from Vostok Station (Russia), 1.100 Km from Dumont D'Urville (France) and Casey (Australia). During the 1998-1999 and 1999-2000 expeditions in Antarctica, some preliminary tests were carried out in order to evaluate the suitability of Dome C site for a permanent geomagnetic observatory. Two parallel data acquisition systems, each equipped with overhauser and flux-gate magnetometers were installed in two shelters at about 300 m from the Base camp. After some tests and checks, the site was considered a good site for geomagnetic investigations. The instrumentation is now in France and in Italy to prepare the instruments and the acquisition systems for the final installation that will take place during the 2004-2005 expedition.

Did clockwise rotation of Antarctica cause the break-up of Gondwanaland? An investigation in the 'deep-keeled cratons' frame for global dynamics

NASA Astrophysics Data System (ADS)

Osmaston, M. F.

2012-04-01

Introduction. The 'deep-keeled cratons' frame for global dynamics is the result of seeking Earth-behaviour answers to the following outside-the-box proposition:- "If cratons have tectospheric keels that reach or approach the 660 km discontinuity, AND the 660 level is an effective barrier to mantle circulation, then obviously (i) when two cratons separate, the upper mantle to put under the nascent ocean must arrive by a circuitous route and, conversely, (ii) if they approach one another, the mantle volume that was in between them must get extruded sideways." Surprisingly it has turned out [1 - 4] that Earth dynamical behaviour for at least the past 150 Ma provides persuasive affirmation of both these expectations and that there is a rational petrological explanation for the otherwise-unexpected immobility of subcratonic material to such depths [5 - 7]. Clockwise rotation of Antarctica? This contribution greatly amplifies my original plate dynamical arguments for suggesting [8] that such rotation is ongoing. Convection is unsuited to causing rotation about a pole within the plate so, as noted then, a gearwheel-like linkage to Africa at the SWIR would provide its clearly CCW (Biscay-Caucasus) relationship to the Mediterranean belt for the past 100 Ma, also seen in its separation from South America. Gearwheel-like linkage of motion requires the presence of some kind of E-W restraint further north. In that case it was the N Africa/Arabia involvement in the Alpide belt, but the earlier opening of the central Atlantic by the eastward motion of Africa, suggests its rigid Gondwanan attachment to Antarctica rotation at that time, with little constraint in the north. Further east, the seafloor data show that Australia-Antarctica separation involved no such opposite rotational linkage, so, with no E-W mechanical constraint in the north by Indonesia, they must have rotated together, as is recorded by Australia's eastward motion to generate the Mesozoic seafloor at its western

Landsat Image Mosaic of Antarctica (LIMA)

USGS Publications Warehouse

,

2007-01-01

For most of us, Antarctica was at best a distant acquaintance. Now, with the Landsat Image Mosaic of Antarctica (LIMA), we are on intimate terms. In stunning, up-close and personal detail, LIMA brings Antarctica to life. Explore this virtually cloudless, seamless, most geometrically accurate, and highest resolution satellite mosaic of Antarctica. A team of scientists from the U.S. Geological Survey, the British Antarctic Survey, and the National Aeronautics and Space Administration, with funding from the National Science Foundation, created LIMA in support of the International Polar Year (IPY; 2007?08). As the first major scientific outcome of the IPY, LIMA truly fulfills the IPY goals. LIMA is an international effort, supports current scientific polar research, encourages new projects, and helps the general public visualize Antarctica and changes happening in this southernmost environment. Researchers and the general public can download LIMA and all component Landsat scenes at no charge.

The genus Unixenus Jones, 1944 (Diplopoda, Penicillata, Polyxenida) in Australia

PubMed Central

Short, Megan; Huynh, Cuong

2011-01-01

Abstract The penicillate genus Unixenus Jones, 1944 is widespread, with species found in Africa, Madagascar, India and Australia. Each of the two Australian species was originally described from single samples from Western Australia. In this study, collections of Penicillata from museums in all states of Australia were examined to provide further details of the two described species, to revise the diagnoses for both the genus and the species, and to better understand the distribution of the two species in Australia. In addition, two new species Unixenus karajinensis sp. n. and Unixenus corticolus sp. n. are described. PMID:22303098

A high-precision digital astrogeodetic traverse in an area of steep geoid gradients close to the coast of Perth, Western Australia

NASA Astrophysics Data System (ADS)

Schack, P.; Hirt, C.; Hauk, M.; Featherstone, W. E.; Lyon, T. J.; Guillaume, S.

2018-01-01

We present results from a new vertical deflection (VD) traverse observed in Perth, Western Australia, which is the first of its kind in the Southern Hemisphere. A digital astrogeodetic QDaedalus instrument was deployed to measure VDs with {˜ } 0.2'' precision at 39 benchmarks with a {{˜ }}1 km spacing. For the conversion of VDs to quasigeoid height differences, the method of astronomical-topographical levelling was applied, based on topographical information from the Shuttle Radar Topography Mission. The astronomical quasigeoid heights are in 20-30 mm (RMS) agreement with three independent gravimetric quasigeoid models, and the astrogeodetic VDs agree to 0.2-0.3'' (north-south) and 0.6-0.9'' (east-west) RMS. Tilt-like biases of {˜ }1 mm over {˜ }1 km are present for all quasigeoid models within {˜ }20 km of the coastline, suggesting inconsistencies in the coastal zone gravity data. The VD campaign in Perth was designed as a low-cost effort, possibly allowing replication in other Southern Hemisphere countries (e.g., Asia, Africa, South America and Antarctica), where VD data are particularly scarce.

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

ERIC Educational Resources Information Center

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…

The tectonics of anorthosite massifs

NASA Technical Reports Server (NTRS)

Seyfert, C. K.

1981-01-01

Anorthosite massifs developed approximately 1.4 to 1.5 billion years ago along an arch which developed parallel to a zone of continental separation as a block which included North America, Europe, and probably Asia separated from a block which included parts of South America, Africa, India, and Australia. Anorthosite massifs also developed at the same time along a belt which runs through the continents which comprise Gondwanaland (South America), Africa, India, Australia, and Antarctica. This was a zone of continental separation which subsequently became a zone of continental collision about 1.2 billion years ago. The northern anorthosite belt also parallels an orogenic belt which was active between 1.8 and 1.7 billion years ago. Heat generated during this mountain building period helped in the formation of the anorthosites.

Aerogeophysical evidence for strike-slip faulting at the boundary between East and West Antarctica: implications for Jurassic magma emplacement and Gondwana breakup models

NASA Astrophysics Data System (ADS)

Jordan, Tom; Ferraccioli, Fausto

2014-05-01

Fragmentation of the Gondwana supercontinent began in the Jurassic and was the most significant reconfiguration of the continents of the southern hemisphere in the last 500 Ma. Jurassic continental rifting began adjacent to South Africa in the Weddell Sea region of Antarctica. This region is therefore critical for understanding the process that initiated supercontinent breakup, including the role of mantle plumes, magmatism, and major plate and microplate re-configurations. However, due to the remote location and blanketing ice sheets, the magmatic and tectonic evolution of the Weddell Sea sector of Antarctica has remained poorly understood and controversial. Our recent aeromagnetic and airborne gravity investigations reveal the inland extent of the Weddell Sea Rift system beneath the West Antarctic Ice Sheet, and indicate the presence of a major left-lateral strike slip fault system, separating the Ellsworth Whitmore block from East Antarctica (Jordan et al., 2013 Tectonophysics). In this study we use 3D inversion of magnetic data to investigate the geometry and emplacement mechanism of Jurassic granites both along the boundary and within the Ellsworth-Whitmore block. Our models demonstrate a high degree of structural control on Jurassic granite emplacement along the newly identified left-lateral Pagano Shear Zone that flanks the Ellsworth-Whitmore block. Other granitoids emplaced further west within the Ellsworth-Whtimore block itself do not appear to have the same structural control, suggesting that this possible microplate or block was relatively more rigid. Extensive and likely more rigid Precambrian basement of Grenvillian-age is clearly delineated from aeromagnetic signatures at the northern edge of the Ellsworth-Whitmore block, lending support to this interpretation. Most intriguing, it that the high amplitude anomalies over the northern margin of the Ellsworth-Whitmore block are remarkably similar to those previously mapped over the Shackleton Range in

Non-linear growth in tree ferns, Dicksonia antarctica and Cyathea australis

PubMed Central

Blair, David P.; Blanchard, Wade; Banks, Sam C.; Lindenmayer, David B.

2017-01-01

Tree ferns are an important structural component of forests in many countries. However, because their regeneration is often unrelated to major disturbances, their age is often difficult to determine. In addition, rates of growth may not be uniform, which further complicates attempts to determine their age. In this study, we measured 5 years of growth of Cyathea australis and Dicksonia antarctica after a large wildfire in 2009 in south-eastern Australia. We found growth rates of these two species were unaffected by aspect and elevation but slope had a minor effect with D. antarctica growing 0.3mm faster for each additional degree of slope. Geographic location influenced growth in both species by up to 12 – 14mm/yr. The most consistent factor influencing growth rate, however, was initial height at the time of the 2009 fire; a finding consistent in both species and all geographic locations. For both tree fern species, individuals that were taller at the commencement of the study had greater overall growth for the duration of the study. This effect did not decrease even among the tallest tree ferns in our study (up to 6 metres tall). Overall, Cyathea australis averaged 73 (± 22)mm/year of growth (± 1SD), with the rate increasing 5mm/yr per metre of additional height. Dicksonia antarctica averaged 33 (± 13)mm/year, increasing by 6mm/yr/m. Growth rates dependent on initial height were unexpected and we discuss possible reasons for this finding. Variable growth rates also suggest that common age estimation methods of dividing height by average growth rate are likely to underestimate the age of short tree ferns, while overestimating the age of tall tree ferns, particularly if they have been subject to a fire. PMID:28493884

Non-linear growth in tree ferns, Dicksonia antarctica and Cyathea australis.

PubMed

Blair, David P; Blanchard, Wade; Banks, Sam C; Lindenmayer, David B

2017-01-01

Tree ferns are an important structural component of forests in many countries. However, because their regeneration is often unrelated to major disturbances, their age is often difficult to determine. In addition, rates of growth may not be uniform, which further complicates attempts to determine their age. In this study, we measured 5 years of growth of Cyathea australis and Dicksonia antarctica after a large wildfire in 2009 in south-eastern Australia. We found growth rates of these two species were unaffected by aspect and elevation but slope had a minor effect with D. antarctica growing 0.3mm faster for each additional degree of slope. Geographic location influenced growth in both species by up to 12 - 14mm/yr. The most consistent factor influencing growth rate, however, was initial height at the time of the 2009 fire; a finding consistent in both species and all geographic locations. For both tree fern species, individuals that were taller at the commencement of the study had greater overall growth for the duration of the study. This effect did not decrease even among the tallest tree ferns in our study (up to 6 metres tall). Overall, Cyathea australis averaged 73 (± 22)mm/year of growth (± 1SD), with the rate increasing 5mm/yr per metre of additional height. Dicksonia antarctica averaged 33 (± 13)mm/year, increasing by 6mm/yr/m. Growth rates dependent on initial height were unexpected and we discuss possible reasons for this finding. Variable growth rates also suggest that common age estimation methods of dividing height by average growth rate are likely to underestimate the age of short tree ferns, while overestimating the age of tall tree ferns, particularly if they have been subject to a fire.

Solar Eclipses Observed from Antarctica

NASA Astrophysics Data System (ADS)

Pasachoff, Jay M.

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 eclipse of 2008 February 7, and will next occur on 2014 April 29. Partial phases as high as 87% coverage were visible and were imaged in Antarctica on 2011 November 25, and in addition to partial phases of the total and annular eclipses listed above, partial phases were visible in Antarctica on 2001 July 2011, 2002 December 4, 2004 April 19, 2006 September 22, 2007 September 11, and 2009 January 26, and will be visible on 2015 September 13, 2016 September 1, 2017 February 26, 2018 February 15, and 2020 December 14. On behalf of the Working Group on Solar Eclipses of the IAU, the poster showed the solar eclipses visible from Antarctica and this article shows a subset (see www.eclipses.info for the full set). A variety of investigations of the Sun and of the response of the terrestrial atmosphere and ionosphere to the abrupt solar cutoff can be carried out at the future eclipses, making the Antarctic observations scientifically useful.

Jovian Antarctica.

NASA Image and Video Library

2017-02-04

Cyclones swirl around the south pole, and white oval storms can be seen near the limb -- the apparent edge of the planet -- in this image of Jupiter's south polar region taken by the JunoCam imager aboard NASA's Juno spacecraft. The image was acquired on February 2, 2017, at 5:52 a.m. PST (8:52 a.m. EST) from an altitude of 47,600 miles (76,600 kilometers) above Jupiter's swirling cloud deck. Prior to the Feb. 2 flyby, the public was invited to vote for their favorite points of interest in the Jovian atmosphere for JunoCam to image. The point of interest captured here was titled "Jovian Antarctica" by a member of the public, in reference to Earth's Antarctica. http://photojournal.jpl.nasa.gov/catalog/PIA21380

A cryptic Gondwana-forming orogen located in Antarctica.

PubMed

Daczko, Nathan R; Halpin, Jacqueline A; Fitzsimons, Ian C W; Whittaker, Joanne M

2018-05-30

The most poorly exposed and least understood Gondwana-forming orogen lies largely hidden beneath ice in East Antarctica. Called the Kuunga orogen, its interpolation between scattered outcrops is speculative with differing and often contradictory trends proposed, and no consensus on the location of any sutures. While some discount a suture altogether, paleomagnetic data from Indo-Antarctica and Australo-Antarctica do require 3000-5000 km relative displacement during Ediacaran-Cambrian Gondwana amalgamation, suggesting that the Kuunga orogen sutured provinces of broadly Indian versus Australian affinity. Here we use compiled data from detrital zircons offshore of East Antarctica that fingerprint two coastal subglacial basement provinces between 60 and 130°E, one of Indian affinity with dominant ca. 980-900 Ma ages (Indo-Antarctica) and one of Australian affinity with dominant ca. 1190-1140 and ca. 1560 Ma ages (Australo-Antarctica). We combine this offshore compilation with existing and new onshore U-Pb geochronology and previous geophysical interpretations to delimit the Indo-Australo-Antarctic boundary at a prominent geophysical lineament which intersects the coast east of Mirny at ~94°E.

Combined Gravimetric-Seismic Crustal Model for Antarctica

NASA Astrophysics Data System (ADS)

Baranov, Alexey; Tenzer, Robert; Bagherbandi, Mohammad

2018-01-01

The latest seismic data and improved information about the subglacial bedrock relief are used in this study to estimate the sediment and crustal thickness under the Antarctic continent. Since large parts of Antarctica are not yet covered by seismic surveys, the gravity and crustal structure models are used to interpolate the Moho information where seismic data are missing. The gravity information is also extended offshore to detect the Moho under continental margins and neighboring oceanic crust. The processing strategy involves the solution to the Vening Meinesz-Moritz's inverse problem of isostasy constrained on seismic data. A comparison of our new results with existing studies indicates a substantial improvement in the sediment and crustal models. The seismic data analysis shows significant sediment accumulations in Antarctica, with broad sedimentary basins. According to our result, the maximum sediment thickness in Antarctica is about 15 km under Filchner-Ronne Ice Shelf. The Moho relief closely resembles major geological and tectonic features. A rather thick continental crust of East Antarctic Craton is separated from a complex geological/tectonic structure of West Antarctica by the Transantarctic Mountains. The average Moho depth of 34.1 km under the Antarctic continent slightly differs from previous estimates. A maximum Moho deepening of 58.2 km under the Gamburtsev Subglacial Mountains in East Antarctica confirmed the presence of deep and compact orogenic roots. Another large Moho depth in East Antarctica is detected under Dronning Maud Land with two orogenic roots under Wohlthat Massif (48-50 km) and the Kottas Mountains (48-50 km) that are separated by a relatively thin crust along Jutulstraumen Rift. The Moho depth under central parts of the Transantarctic Mountains reaches 46 km. The maximum Moho deepening (34-38 km) in West Antarctica is under the Antarctic Peninsula. The Moho depth minima in East Antarctica are found under the Lambert Trench (24

The Meteoritical Bulletin, No. 87, 2003 July

USGS Publications Warehouse

Russell, S.S.; Zipfel, J.; Folco, L.; Jones, R.; Grady, M.M.; McCoy, T.; Grossman, J.N.

2003-01-01

Meteoritical Bulletin No. 87 lists information for 1898 newly classified meteorites, comprising 1048 from Antarctica, 462 from Africa, 356 from Asia (355 of which are from Oman), 18 from North America, 5 from South America, 5 from Europe, and 3 from Australia. Information is provided for 10 falls (Beni M'hira, Elbert, Gasseltepaoua, Hiroshima, Kilabo, Neuschwanstein, Park Forest, Pe??, Pe??te??lkole??, and Thuathe). Two of these-Kilabo and Thuathe-fell on the same day. Orbital characteristics could be calculated for Neuschwanstein. Noteworthy specimens include 8 Martian meteorites (5 from Sahara, 2 from Oman and 1 from Antarctica), 13 lunar meteorites (all except one from Oman), 3 irons, 3 pallasites, and many carbonaceous chondrites and achondrites.

The Rapid Drift of the Indian Tectonic Plate

NASA Astrophysics Data System (ADS)

Kumar, P.; Yuan, X.; Kumar, R.; Kind, R.; Li, X.; Chadha, R.

2007-12-01

The breakup of the supercontinent Gondwanaland into Africa, Antarctica, Australia and India about 140 million years ago and consequently the opening of the Indian Ocean was caused by heating of the lithosphere from below by a large plume whose relicts are the Marion, Kerguelen and Reunion plumes. Plate reconstructions based on paleomagnetic data suggest that the Indian plate attained a very high speed (18-20 cm/yr during late Cretaceous) subsequent to its breakup from the Gondwanaland and slowed down to ~5 cm/yr since the continental collision with Asia during the last ~50 Ma. The Australian and African plates moved comparatively lesser distances and at much lesser speed of 2-4 cm/yr. Antarctica remained almost stationary. This super mobility makes India unique compared to the other fragments of Gondwanaland. We propose that when the parts of Gondwanaland were separated by the plume, the penetration of their lithospheric roots into the asthenosphere played an important role in determining their speed. We estimated the thickness of the lithospheric plates of the different parts of Gondwanaland around the Indian Ocean using the S-receiver function technique. We found that the part of Gondwanaland with clearly the thinnest lithosphere has travelled with the highest speed - India. The lithospheric root in South Africa, Australia and Antarctica is between 180 and 300 km deep. The Indian lithosphere is in contrast only about 100 km thick. Our interpretation is that the plume that partitioned Gondwanaland has also melted the lower half of the Indian lithosphere thus permitting faster motion due to the ridge push or slab pull.

Phaeosphaeria deschampsii (Ascomycota): A new parasite species of Deschampsia antarctica (Poaceae) described to Antarctica.

PubMed

Putzke, Jair; Pereira, Antonio B

2016-01-01

This study presents the description of Phaeosphaeria deschampsii, which was found in plant communities from Half Moon Island, South Shetland Archipelago, Antarctica, in February 2014. Many patches of Deschampsia antarctica (Poaceae), the only indigenous Poaceae specie in Antarctic, were found dead, parasitized by a fungi pathogen. Based on the shape of its perithecia, with oblique neck, erumpent in the grass tissues, ascospore form and septation, the specie was identified as new to science.

Total Solar Eclipse of 2002 December 04

NASA Technical Reports Server (NTRS)

Espenak, Fred; Anderson, Jay

2001-01-01

On 2002 December 04, a total eclipse of the Sun will be visible from within a narrow corridor which traverses the Southern Hemisphere. The path of the Moon's umbral shadow begins in the South Atlantic, crosses southern Africa and the Indian Ocean, and ends at sunset in southern Australia. A partial eclipse will be seen within the much broader path of the Moon's penumbral shadow, which includes the southern two thirds of Africa, Antarctica, Indian Ocean and Australia. Detailed predictions for this event are presented and include besselian elements, geographic coordinates of the path of totality, physical ephemeris of the umbra, topocentric limb profile corrections, local circumstances for approximately 400 cities, maps of the eclipse path, weather prospects, the lunar limb profile and the sky during totality. Information on safe eclipse viewing and eclipse photography is included.

Rapid diversification in Australia and two dispersals out of Australia in the globally distributed bee genus, Hylaeus (Colletidae: Hylaeinae).

PubMed

Kayaalp, Pelin; Schwarz, Michael P; Stevens, Mark I

2013-03-01

Hylaeus is the only globally distributed colletid bee genus, with subgeneric and species-level diversity highest in Australia. We used one mitochondrial and two nuclear genes to reconstruct a phylogeny using Bayesian analyses of this genus based on species from Australia, Asia, Africa, Europe, Hawai'i, the New World and New Zealand. Our results concord with a ca. 30Mya Hylaeus crown age inferred by earlier studies, and we show that Hylaeus originated in Australia. Our phylogeny indicates only two dispersal events out of Australia, both shortly after the initial diversification of extant taxa. One of these dispersals was into New Zealand with only a minor subsequent radiation, but the second dispersal out of Australia resulted in a world-wide distribution. This second dispersal and radiation event, combined with very extensive early radiation of Hyleaus in Australia, poses a conundrum: what kinds of biogeographical and ecological factors could simultaneously drive global dispersal, yet strongly constrain further successful migrations out of Australia when geographical barriers appear to be weak? We argue that for hylaeine bees movement into new niches and enemy-free spaces may have favoured initial dispersal events, but that subsequent dispersals would not have entailed the original benefits of new niche space. Copyright © 2012 Elsevier Inc. All rights reserved.

Paleomagnetic study of the northern Ford Ranges, western Marie Byrd Land, West Antarctica: Motion between West and East Antarctica

NASA Astrophysics Data System (ADS)

Luyendyk, Bruce; Cisowski, Stan; Smith, Christine; Richard, Steve; Kimbrough, David

1996-02-01

A paleomagnetic study of Paleozoic and Mesozoic crystalline rocks in the northern Ford Ranges of Marie Byrd Land, West Antarctica, has determined a middle Cretaceous (circa 100 Ma) paleomagnetic pole and provided constraints on possible clockwise rotation of these ranges and on the rifting of east Gondwana. The 40Ar/39Ar thermochronology data from the Fosdick Mountains record a period of rapid cooling from ˜700°C beginning at ˜100 Ma. We relate this to extension, intrusion, and uplift associated with the beginning of rifting between Campbell Plateau and Marie Byrd Land. All rocks from the Fosdick and Chester Mountains are normally polarized. We interpret thermochronology and paleomagnetic data to infer that the region was extensively remagnetized in middle Cretaceous time. Inclinations in samples from the Chester Mountains are less steep than those from the Fosdick Mountains, which we interpret as ˜25° of south tilting of the Chesters. We interpret cooling age data for the time of magnetization to infer that the tilting began after 105 Ma and ended prior to 103 Ma. We further interpret this as constraining the beginning of extension between the Campbell Plateau and western Marie Byrd Land to the interval 105 to 103 Ma. Virtual geomagnetic poles from samples of Early Carboniferous age granodiorite from the western Phillips Mountains lie on the late Paleozoic apparent polar wander path for Australia transferred to Antarctica. Directions from 29 sites in the central and eastern Phillips and Fosdick Mountains give a Middle Cretaceous paleomagnetic pole at 222.3° E, 70.5° S (A95 6.1°, KAPPA 20.0). This pole is indistinguishable from other Middle Cretaceous poles for studies further east in Marie Byrd Land. Combining middle Cretaceous poles determined for three other studies of the Antarctic Peninsula, Thurston Island, and the Ruppert-Hobbs coasts with ours gives a Pacific West Antarctic pole at 215.2° E, 73.5° S (A95 4.0°, KAPPA 528.9). This pole is

Paleomagnetic study of the northern Ford Ranges, western Marie Byrd Land, West Antarctica: Motion between West and East Antarctica

USGS Publications Warehouse

Luyendyk, B.; Cisowski, S.; Smith, C.; Richard, S.; Kimbrough, D.

1996-01-01

A paleomagnetic study of Paleozoic and Mesozoic crystalline rocks in the northern Ford Ranges of Marie Byrd Land, West Antarctica, has determined a middle Cretaceous (circa 100 Ma) paleomagnetic pole and provided constraints on possible clockwise rotation of these ranges and on the rifting of east Gondwana. The 40Ar/39Ar thermochronology data from the Fosdick Mountains record a period of rapid cooling from ???700??C beginning at ???100 Ma. We relate this to extension, intrusion, and uplift associated with the beginning of rifting between Campbell Plateau and Marie Byrd Land. All rocks from the Fosdick and Chester Mountains are normally polarized. We interpret thermochronology and paleomagnetic data to infer that the region was extensively remagnetized in middle Cretaceous time. Inclinations in samples from the Chester Mountains are less steep than those from the Fosdick Mountains, which we interpret as ???25?? of south tilting of the Chesters. We interpret cooling age data for the time of magnetization to infer that the tilting began after 105 Ma and ended prior to 103 Ma. We further interpret this as constraining the beginning of extension between the Campbell Plateau and western Marie Byrd Land to the interval 105 to 103 Ma. Virtual geomagnetic poles from samples of Early Carboniferous age granodiorite from the western Phillips Mountains lie on the late Paleozoic apparent polar wander path for Australia transferred to Antarctica. Directions from 29 sites in the central and eastern Phillips and Fosdick Mountains give a Middle Cretaceous paleomagnetic pole at 222.3?? E, 70.5?? S (A95 6.1??, KAPPA 20.0). This pole is indistinguishable from other Middle Cretaceous poles for studies further east in Marie Byrd Land. Combining middle Cretaceous poles determined for three other studies of the Antarctic Peninsula. Thurston Island, and the Ruppert-Hobbs coasts with ours gives a Pacific West Antarctic pole at 215.2?? E, 73.5?? S (A95 4.0??, KAPPA 528.9). This pole is

Space analogue studies in Antarctica

NASA Technical Reports Server (NTRS)

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.

Space analogue studies in Antarctica

NASA Astrophysics Data System (ADS)

Lugg, D.; Shepanek, M.

1999-09-01

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 mltogen 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.

Antarctica: Scientific Journeys from McMurdo to the Pole.

ERIC Educational Resources Information Center

Brand, Judith, Ed.

2002-01-01

This issue of Exploratorium Magazine focuses on Antarctica. Antarctica has one of the most extreme climates in the world with an untouched environment inviting researchers with great opportunities for study. This issue describes the journey of four Exploratorium staff members to frozen Antarctica. Chapters include: (1) "Life at the Bottom of…

Australia in German Geography Textbooks for Middle Schools

ERIC Educational Resources Information Center

Hamann, Berta

2007-01-01

German Geography textbooks are structured using the principle of "Systematic Geography based on a regional example" that is predominant in Germany. Compared to other macroregions such as Europe, North America, Africa, or Asia, however, Australia is presented less frequently in school textbooks. Those textbooks which deal with Australia…

A Battle Lost? Report on Two Centuries of Invasion and Management of Lantana camara L. in Australia, India and South Africa

PubMed Central

Bhagwat, Shonil A.; Breman, Elinor; Thekaekara, Tarsh; Thornton, Thomas F.; Willis, Katherine J.

2012-01-01

Recent discussion on invasive species has invigorated the debate on strategies to manage these species. Lantana camara L., a shrub native to the American tropics, has become one of the worst weeds in recorded history. In Australia, India and South Africa, Lantana has become very widespread occupying millions of hectares of land. Here, we examine historical records to reconstruct invasion and management of Lantana over two centuries and ask: Can we fight the spread of invasive species or do we need to develop strategies for their adaptive management? We carried out extensive research of historical records constituting over 75% of records on invasion and management of this species in the three countries. The records indicate that governments in Australia, India and South Africa have taken aggressive measures to eradicate Lantana over the last two centuries, but these efforts have been largely unsuccessful. We found that despite control measures, the invasion trajectory of Lantana has continued upwards and that post-war land-use change might have been a possible trigger for this spread. A large majority of studies on invasive species address timescales of less than one year; and even fewer address timescales of >10 years. An understanding of species invasions over long time-scales is of paramount importance. While archival records may give only a partial picture of the spread and management of invasive species, in the absence of any other long-term dataset on the ecology of Lantana, our study provides an important insight into its invasion, spread and management over two centuries and across three continents. While the established paradigm is to expend available resources on attempting to eradicate invasive species, our findings suggest that in the future, conservationists will need to develop strategies for their adaptive management rather than fighting a losing battle. PMID:22403653

The Meteoritical Bulletin, No. 97

NASA Astrophysics Data System (ADS)

Weisberg, Michael K.; Smith, Caroline; Benedix, Gretchen; Herd, Christopher D. K.; Righter, Kevin; Haack, Henning; Yamaguchi, Akira; Chennaoui Aoudjehane, Hasnaa; Grossman, Jeffrey N.

2010-03-01

In this edition of The Meteoritical Bulletin, a total of 506 newly approved meteorite names with their relevant data are reported. These include 354 from northwest Africa, 31 from the Americas, 15 from Antarctica (Koreamet), 85 from Asia, 20 from Australia, and 1 from Europe. Among these meteorites are 2 falls, Grimsby (Canada) and Santa Lucia (2008) (Argentina). Also described are a CM with low degree of alteration, new ungrouped chondrites and achondrites, and 4 Martian meteorites.

A genomic history of Aboriginal Australia.

PubMed

Malaspinas, Anna-Sapfo; Westaway, Michael C; Muller, Craig; Sousa, Vitor C; Lao, Oscar; Alves, Isabel; Bergström, Anders; Athanasiadis, Georgios; Cheng, Jade Y; Crawford, Jacob E; Heupink, Tim H; Macholdt, Enrico; Peischl, Stephan; Rasmussen, Simon; Schiffels, Stephan; Subramanian, Sankar; Wright, Joanne L; Albrechtsen, Anders; Barbieri, Chiara; Dupanloup, Isabelle; Eriksson, Anders; Margaryan, Ashot; Moltke, Ida; Pugach, Irina; Korneliussen, Thorfinn S; Levkivskyi, Ivan P; Moreno-Mayar, J Víctor; Ni, Shengyu; Racimo, Fernando; Sikora, Martin; Xue, Yali; Aghakhanian, Farhang A; Brucato, Nicolas; Brunak, Søren; Campos, Paula F; Clark, Warren; Ellingvåg, Sturla; Fourmile, Gudjugudju; Gerbault, Pascale; Injie, Darren; Koki, George; Leavesley, Matthew; Logan, Betty; Lynch, Aubrey; Matisoo-Smith, Elizabeth A; McAllister, Peter J; Mentzer, Alexander J; Metspalu, Mait; Migliano, Andrea B; Murgha, Les; Phipps, Maude E; Pomat, William; Reynolds, Doc; Ricaut, Francois-Xavier; Siba, Peter; Thomas, Mark G; Wales, Thomas; Wall, Colleen Ma'run; Oppenheimer, Stephen J; Tyler-Smith, Chris; Durbin, Richard; Dortch, Joe; Manica, Andrea; Schierup, Mikkel H; Foley, Robert A; Lahr, Marta Mirazón; Bowern, Claire; Wall, Jeffrey D; Mailund, Thomas; Stoneking, Mark; Nielsen, Rasmus; Sandhu, Manjinder S; Excoffier, Laurent; Lambert, David M; Willerslev, Eske

2016-10-13

The population history of Aboriginal Australians remains largely uncharacterized. Here we generate high-coverage genomes for 83 Aboriginal Australians (speakers of Pama-Nyungan languages) and 25 Papuans from the New Guinea Highlands. We find that Papuan and Aboriginal Australian ancestors diversified 25-40 thousand years ago (kya), suggesting pre-Holocene population structure in the ancient continent of Sahul (Australia, New Guinea and Tasmania). However, all of the studied Aboriginal Australians descend from a single founding population that differentiated ~10-32 kya. We infer a population expansion in northeast Australia during the Holocene epoch (past 10,000 years) associated with limited gene flow from this region to the rest of Australia, consistent with the spread of the Pama-Nyungan languages. We estimate that Aboriginal Australians and Papuans diverged from Eurasians 51-72 kya, following a single out-of-Africa dispersal, and subsequently admixed with archaic populations. Finally, we report evidence of selection in Aboriginal Australians potentially associated with living in the desert.

Major strike-slip faulting along the tectonic boundary between East and West Antarctica: implications for early Gondwana break-up and Jurassic granitic magma emplacement

NASA Astrophysics Data System (ADS)

Jordan, T. A.; Ferraccioli, F.; Anderson, L.; Ross, N.; Corr, H.; Leat, P. T.; Bingham, R.; Rippin, D. M.; Le Brocq, A. M.; Siegert, M. J.

2013-12-01

The fragmentation of the Gondwana supercontinent began with continental rifting between the Weddell Sea region of Antarctica and South Africa during the Jurassic. This initial Jurassic phase of continental rifting is critical for understanding the process that initiated supercontinent breakup and dispersal, including the role of mantle plumes and major intracrustal tectonic structures. However, due to the remote location and blanketing ice sheets, the tectonic and magmatic evolution of the Weddell Sea Sector of Antarctica has remained relatively poorly understood. Our recent aeromagnetic and airborne gravity investigations have revealed the inland extent of the Weddell Sea Rift system beneath the West Antarctic Ice Sheet, and indicate the presence of a major left-lateral strike slip fault system separating the Ellsworth Whitmore block (a possible exotic microcontinent derived from the Natal Embayment, or the Shackleton Range region of East Antarctica) from East Antarctica (Jordan et al., 2013 Tectonophysics). In this study we use GPlates plate-tectonic reconstruction software to start evaluating the influence of strike-slip faulting between East and West Antarctica on Gondwana breakup models. Specifically, we investigate the possibility of poly-phase motion along the fault system and explore scenarios involving more diffuse strike slip faulting extending into the interior of East Antarctica in the hinterland of the Transantarctic Mountains. Our preliminary models suggest that there may be a link between the prominent step in the flank of the later Cretaceous-Cenozoic West Antarctic Rift System (at the southern end of Ellsworth-Whitmore Block) and the earlier Jurassic Weddell Sea rift system. Additionally, we present preliminary joint 3D magnetic and gravity models to investigate the crustal architecture of the proposed strike-slip fault system and assess its influence on the emplacement of voluminous Jurassic granitic magmatism along the boundary of the Ellsworth

The rapid drift of the Indian tectonic plate.

PubMed

Kumar, Prakash; Yuan, Xiaohui; Kumar, M Ravi; Kind, Rainer; Li, Xueqing; Chadha, R K

2007-10-18

The breakup of the supercontinent Gondwanaland into Africa, Antarctica, Australia and India about 140 million years ago, and consequently the opening of the Indian Ocean, is thought to have been caused by heating of the lithosphere from below by a large plume whose relicts are now the Marion, Kerguelen and Réunion plumes. Plate reconstructions based on palaeomagnetic data suggest that the Indian plate attained a very high speed (18-20 cm yr(-1) during the late Cretaceous period) subsequent to its breakup from Gondwanaland, and then slowed to approximately 5 cm yr(-1) after the continental collision with Asia approximately 50 Myr ago. The Australian and African plates moved comparatively less distance and at much lower speeds of 2-4 cm yr(-1) (refs 3-5). Antarctica remained almost stationary. This mobility makes India unique among the fragments of Gondwanaland. Here we propose that when the fragments of Gondwanaland were separated by the plume, the penetration of their lithospheric roots into the asthenosphere were important in determining their speed. We estimated the thickness of the lithospheric plates of the different fragments of Gondwanaland around the Indian Ocean by using the shear-wave receiver function technique. We found that the fragment of Gondwanaland with clearly the thinnest lithosphere is India. The lithospheric roots in South Africa, Australia and Antarctica are between 180 and 300 km deep, whereas the Indian lithosphere extends only about 100 km deep. We infer that the plume that partitioned Gondwanaland may have also melted the lower half of the Indian lithosphere, thus permitting faster motion due to ridge push or slab pull.

One Dimensional Backstripping Results from IODP Expedition 318, Site U1356: Tectonic Implications for the Wilkes Land Margin of Antarctica

NASA Astrophysics Data System (ADS)

Hayden, T. G.; Kominz, M. A.; González, J. J.; Escutia, C.; Brinkhuis, H.; Scientific Party of IODP Expedition 318

2011-12-01

The Wilkes Land margin of Antarctica is the conjugate margin of the Great Australian Bight, which underwent extension, thinning and rifting from ~160 Ma until breakup at ~83 Ma. Both Wilkes Land and the Great Australian Bight are considered passive margins, and were thought to be tectonically inactive since breakup at 83 Ma. We have backstripped the U1356 Core recovered from the continental rise off Wilkes Land, Antarctica by IODP Expedition 318. Backstripping input included lithological and sedimentary analysis, paleo-environmental indicators, combined paleomagnetic and biostratigraphic chronologies, and physical properties measurements. Tectonic subsidence shows a major event between 50 and 33.6 Ma, a time represented by a hiatus in the U1356 core. The magnitude of subsidence requires it to be tectonic in origin, and the timing matches with a reorganization of plate motions that represents the transition from slow spreading to fast spreading between Antarctica and Australia, which occurred at approximately 43 Ma. Coupled with a regional seismic framework, and using other Expedition 318 site analyses, the Wilkes Land margin is shown to be far more complex then the simple passive margin currently assumed. We explore several possible mechanisms for the subsidence and erosion observed; including thermal uplift due to continental insulation of the asthenosphere and it's interaction with a recently rifted margin, asthenospheric convection, transtensional or transpressional basin development and loading, and edge-driven asthenospheric convection.

The seismic noise environment of Antarctica

DOE PAGES

Anthony, Robert E.; Aster, Richard C.; Wiens, Douglas; ...

2014-11-26

Seismographic coverage of Antarctica prior to 2007 consisted overwhelmingly of a handful of long running and sporadically deployed transient stations, many of which were principally collocated with scientific research stations. Thus, despite very cold temperatures, sunless winters, challenging logistics, and extreme storms, recent developments in polar instrumentation driven by new scientific objectives have opened up the entirety of Antarctica to year–round and continuous seismological observation (e.g., Nyblade et al., 2012).

Antarctica: Cooling or Warming?

NASA Astrophysics Data System (ADS)

Bunde, Armin; Ludescher, Josef; Franzke, Christian

2013-04-01

We consider the 14 longest instrumental monthly mean temperature records from the Antarctica and analyse their correlation properties by wavelet and detrended fluctuation analysis. We show that the stations in the western and the eastern part of the Antarctica show significant long-term memory governed by Hurst exponents close to 0.8 and 0.65, respectively. In contrast, the temperature records at the inner part of the continent (South Pole and Vostok), resemble white noise. We use linear regression to estimate the respective temperature differences in the records per decade (i) for the annual data, (ii) for the summer and (iii) for the winter season. Using a recent approach by Lennartz and Bunde [1] we estimate the respective probabilities that these temperature differences can be exceeded naturally without inferring an external (anthropogenic) trend. We find that the warming in the western part of the continent and the cooling at the South Pole is due to a gradually changes in the cold extremes. For the winter months, both cooling and warming are well outside the 95 percent confidence interval, pointing to an anthropogenic origin. In the eastern Antarctica, the temperature increases and decreases are modest and well within the 95 percent confidence interval. [1] S. Lennartz and A. Bunde, Phys. Rev. E 84, 021129 (2011)

Astronomy in Antarctica

NASA Astrophysics Data System (ADS)

Burton, Michael G.

2010-10-01

Antarctica provides a unique environment for astronomers to practice their trade. The cold, dry and stable air found above the high Antarctic plateau, as well as the pure ice below, offers new opportunities for the conduct of observational astronomy across both the photon and the particle spectrum. The summits of the Antarctic 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, at stations run by the USA, France/Italy, China, Japan and the USA, respectively. The astronomy conducted from Antarctica includes optical, infrared, terahertz and sub-millimetre astronomy, measurements of cosmic microwave background anisotropies, solar astronomy, as well as high energy astrophysics involving the 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 sites. In this article, we summarise the facets of Antarctica that are driving developments in astronomy there, and review the results of the site testing experiments undertaken to quantify those characteristics of the Antarctic plateau relevant for astronomical observation. We also outline the historical development of the astronomy on the continent, and then review the principal scientific results to have emerged over the past three decades of activity in the discipline. These range from determination of the dominant frequencies of the 5 min solar oscillation in 1979 to the highest angular scale measurements yet made of the power spectrum of the CMBR anisotropies in 2010. They span through infrared views of the galactic ecology in star

Byrd Glacier, Antarctica

NASA Image and Video Library

2008-11-17

Byrd Glacier is a major glacier in Antarctica; it drains an extensive area of the polar plateau and flows eastward between the Britannia Range and the Churchill Mountains to discharge into the Ross Ice Shelf. This image is from NASA Terra satellite.

Surface winds over West Antarctica

NASA Astrophysics Data System (ADS)

Bromwich, David

1993-07-01

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.

Psychrotolerant Anaerobes from Lake Podprudnoe, Antarctica and Penguin Spheniscus demersus Colony, South Africa

NASA Technical Reports Server (NTRS)

Guisler, Melissa; Pikuta, Elena V.; Townsend, Alisa; Hoover, Richard B.

2009-01-01

The study of a sample collected from a wind-made ice sculpture near Lake Podprudnoe, Antarctica led to the isolation of the psychrotolerant strain ISLP-3. Cells of the new isolate are vibrio-shaped that measure 0.5 x 1.0-3.0 micron in size. Growth occurs within the temperature range 5-35 C with the optimum at 22 C. Salinity range for growth is 0-2 % NaCl with the optimum at 0.25 %. The new isolate grows within a pH range from 6.0 to 9.5 with the optimum at 7.5. Strain ISLP-3 is saccharolytic, growing on the following substrates: D-glucose, D-ribose, D-fructose, D-arabinose, maltose, sucrose, D-trehalose, D-mannose, D-cellobiose, lactose, starch, chitin, triethylamine, N-acetylglucosamine, and urea. The best growth occurred on D-cellobiose. An environmental sample of pond water near a colony of the endemic species of African penguins, Spheniscus demersus, was collected in February 2008 and delivered directly to the Astrobiology laboratory at NSSTC. The microbiological study of this sample led to the isolation of two psychrotolerant strains ARHSd-7G and ARHSd-9G. Both strains are strictly anaerobic bacteria and are able to grow at high pH and low temperatures. The cells of strain ARHSd-7G are motile, vibrio-shaped, spore-forming cells. Optimal growth of this strain occurs at 30 C, 3 % NaCl, and pH 8.9. The isolate ARHSd-7G combines sugarlytic and proteolytic metabolisms, growing on some proteolysis products including peptone and yeast extract and a number of sugars. The second isolate, ARHSd-9G, exhibits thin, elongated rods that measure 0.4 x 3-5 micron. The cells are motile and spore-forming. Optimal growth of strain ARHSd-9G occurs at 30 C, 1.75 % NaCl, and pH 8.5. The strain ARHSd-9G is sugarlytic, growing well on substrates such as D-glucose, sucrose, D-cellobiose, maltose, fructose, D-mannose, and trehalose (the only exception is positive growth on yeast extract). In this report, the physiological and morphological characteristics of the novel psychrotolerant

From Extraction to Knowledge Reproduction: The Impact of Australia's Development Awards on Uganda and Mozambique

ERIC Educational Resources Information Center

Amazan, Rose C.; Negin, Joel; Howie, Leanne; Wood, Julian

2016-01-01

With the renewed emphasis on higher education as an agent for development and economic growth, Australia has joined other Western countries in contributing to increasing the intellectual workforce of Africa[1]. While Australia has provided scholarships to Africans for more than three decades, since 2005, the Australian Government has dramatically…

Married to Antarctica.

ERIC Educational Resources Information Center

Monastersky, Richard

1991-01-01

A novel theory about Earth's ancient history is presented. It is proposed that North America and Antarctica once lay side by side for perhaps as long as a billion years. The importance of these continental connections to geology and other disciplines is discussed. (KR)

Dry Valleys, Antarctica

NASA Image and Video Library

2009-11-02

The McMurdo Dry Valleys are a row of valleys west of McMurdo Sound, Antarctica. They are so named because of their extremely low humidity and lack of snow and ice cover. This image was acquired December 8, 2002 by NASA Terra spacecraft.

Glaciers of Antarctica

USGS Publications Warehouse

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

Galileo spacecraft solid-state imaging system view of Antarctica

NASA Technical Reports Server (NTRS)

1990-01-01

Galileo spacecraft solid-state imaging system view of Antarctica was taken during its first encounter with the Earth. This color picture of Antarctica is part of a mosaic of pictures covering the entire polar continent showing the Ross Ice Shelf and its border with the sea and mountains poking through the ice near the McMurdo Station. From top to bottom, the frame looks across about half of Antarctica. View provided by the Jet Propulsion Laboratory (JPL) with alternate number P-37297.

Complete genome sequence of Pseudomonas antarctica PAMC 27494, a bacteriocin-producing psychrophile isolated from Antarctica.

PubMed

Lee, Jaejin; Cho, Yong-Joon; Yang, Jae Young; Jung, You-Jung; Hong, Soon Gyu; Kim, Ok-Sun

2017-10-10

Antimicrobial-producing, cold-adapted microorganisms have great potential for biotechnological applications in food, pharmaceutical, and cosmetic industries. Pseudomonas antarctica PAMC 27494, a psychrophile exhibiting antimicrobial activity, was isolated from an Antarctic freshwater sample. Here we report the complete genome of P. antarctica PAMC 27494. The strain contains a gene cluster encoding microcin B which inhibits DNA regulations by targeting the DNA gyrase. PAMC 27494 may produce R-type pyocins and also contains a complete set of proteins for the biosynthesis of adenosylcobalamin and possibly induces plant growth by supplying pyrroloquinoline quionone molecules. Copyright © 2017 Elsevier B.V. All rights reserved.

The Dispersal of East Gondwana from Continental Breakup to the Start of the Cretaceous Quiet Zone

NASA Astrophysics Data System (ADS)

Davis, J. K.; Lawver, L. A.; Norton, I. O.; Gahagan, L.

2014-12-01

Existing plate models for the breakup of Africa and East Gondwana (Australia, East Antarctica, India, Madagascar, the Seychelles, and Sri Lanka) are problematic and require revision. Specific problems include the utilization of dubious Gondwana configurations, improbable plate motion, and/or a failure to satisfy the holistic marine magnetic anomaly data. I present here a new model for the breakup of East Gondwana. This new model begins from a constrained, pre-breakup, Gondwana configuration. Out of this initial "tight-fit" configuration, East Gondwana rifts from West Gondwana (Africa & South America) as a cohesive unit. During this breakup and subsequent seafloor spreading, East Gondwana is devoid of any internal compression or anomalous plate motion. The overall motion of East Gondwana is constrained by seafloor spreading in the coeval Somali Basin and Mozambique/Riiser Larsen Basins. Seafloor spreading in these basins is modeled using existing marine magnetic anomaly interpretations and satellite-derived gravity data. Our model is uniquely able to satisfy the magnetic anomaly observations in both of the aforementioned basins without invoking improbable plate motion or configurations. Additionally, our plate model provides valuable insight into the breakup of India and East Antarctica. In this model, we fix India to Madagascar from breakup to 90 Ma, thus eventual separation between India and East Antarctica is an output, not an input of our model. We suggest that this separation occurred diachronously from ~140 Ma in the east to ~120 Ma in the west. This modeled motion between India and East Antarctica agrees well with geophysical observations from the margin of East Antarctica and our preliminary analysis of margin character and variability.

Practical analysis of tide gauges records from Antarctica

NASA Astrophysics Data System (ADS)

Galassi, Gaia; Spada, Giorgio

2015-04-01

We have collected and analyzed in a basic way the currently available time series from tide gauges deployed along the coasts of Antarctica. The database of the Permanent Service for Mean Sea Level (PSMSL) holds relative sea level information for 17 stations, which are mostly concentrated in the Antarctic Peninsula (8 out of 17). For 7 of the PSMSL stations, Revised Local Reference (RLR) monthly and yearly observations are available, spanning from year 1957.79 (Almirante Brown) to 2013.95 (Argentine Islands). For the remaining 11 stations, only metric monthly data can be obtained during the time window 1957-2013. The record length of the available time series is not generally exceeding 20 years. Remarkable exceptions are the RLR station of Argentine Island, located in the Antarctic Peninsula (AP) (time span: 1958-2013, record length: 54 years, completeness=98%), and the metric station of Syowa in East Antarctica (1975-2012, 37 years, 92%). The general quality (geographical coverage and length of record) of the time series hinders a coherent geophysical interpretation of the relative sea-level data along the coasts of Antarctica. However, in an attempt to characterize the relative sea level signals available, we have stacked (i.e., averaged) the RLR time series for the AP and for the whole Antarctica. The so obtained time series have been analyzed using simple regression in order to estimate a trend and a possible sea-level acceleration. For the AP, the the trend is 1.8 ± 0.2 mm/yr and for the whole Antarctica it is 2.1 ± 0.1 mm/yr (both during 1957-2013). The modeled values of Glacial Isostatic Adjustment (GIA) obtained with ICE-5G(VM2) using program SELEN, range between -0.7 and -1.6 mm/yr, showing that the sea-level trend recorded by tide gauges is strongly influenced by GIA. Subtracting the average GIA contribution (-1.1 mm/yr) to observed sea-level trend from the two stacks, we obtain 3.2 and 2.9 mm/yr for Antarctica and AP respectively, which are interpreted

Rethinking the dispersal of Homo sapiens out of Africa.

PubMed

Groucutt, Huw S; Petraglia, Michael D; Bailey, Geoff; Scerri, Eleanor M L; Parton, Ash; Clark-Balzan, Laine; Jennings, Richard P; Lewis, Laura; Blinkhorn, James; Drake, Nick A; Breeze, Paul S; Inglis, Robyn H; Devès, Maud H; Meredith-Williams, Matthew; Boivin, Nicole; Thomas, Mark G; Scally, Aylwyn

2015-01-01

Current fossil, genetic, and archeological data indicate that Homo sapiens originated in Africa in the late Middle Pleistocene. By the end of the Late Pleistocene, our species was distributed across every continent except Antarctica, setting the foundations for the subsequent demographic and cultural changes of the Holocene. The intervening processes remain intensely debated and a key theme in hominin evolutionary studies. We review archeological, fossil, environmental, and genetic data to evaluate the current state of knowledge on the dispersal of Homo sapiens out of Africa. The emerging picture of the dispersal process suggests dynamic behavioral variability, complex interactions between populations, and an intricate genetic and cultural legacy. This evolutionary and historical complexity challenges simple narratives and suggests that hybrid models and the testing of explicit hypotheses are required to understand the expansion of Homo sapiens into Eurasia. © 2015 Wiley Periodicals, Inc.

Anthropogenic impacts on marine ecosystems in Antarctica.

PubMed

Aronson, Richard B; Thatje, Sven; McClintock, James B; Hughes, Kevin A

2011-03-01

Antarctica is the most isolated continent on Earth, but it has not escaped the negative impacts of human activity. The unique marine ecosystems of Antarctica and their endemic faunas are affected on local and regional scales by overharvesting, pollution, and the introduction of alien species. Global climate change is also having deleterious impacts: rising sea temperatures and ocean acidification already threaten benthic and pelagic food webs. The Antarctic Treaty System can address local- to regional-scale impacts, but it does not have purview over the global problems that impinge on Antarctica, such as emissions of greenhouse gases. Failure to address human impacts simultaneously at all scales will lead to the degradation of Antarctic marine ecosystems and the homogenization of their composition, structure, and processes with marine ecosystems elsewhere. © 2011 New York Academy of Sciences.

Intelsat TDMA and its implementation in Australia

NASA Astrophysics Data System (ADS)

Howe, Stuart

The developmental history and characteristics of the Intelsat digital communications network are surveyed, with a focus on the current implementation status in Australia. Topics addressed include the fundamental principles and advantages of a TDMA system, the hardware required for a TDMA traffic station, and the Intelsat Indian Ocean Primary satellite network. Detailed consideration is given to TDMA test equipment (burst-mode link analyzers, PCM DSI test sets, burst-power meters, burst negators, and reference burst generators), terminal integration with terrestrial and RF links (TWT sharing and equalization), equipment compatibility, and traffic. Plans call for 950 TDMA circuits by the end of 1990, representing about 36.5 percent of the traffic between Australia and Europe, Africa, India and Pakistan, and the Middle East.

Antarctica as a Martian model.

NASA Technical Reports Server (NTRS)

Vishniac, W. V.; Mainzer, S. E.

1973-01-01

Results of a survey of a variety of environments in the dry valleys of Antarctica, ranging from mountain crests to valley floors. The main purpose of the investigation was the determination of active microbial multiplication in the soil. A series of techniques was employed which permitted the detection of bacterial growth in situ. All evidence points to an active growth of micro-organisms in the Antarctic soil in all locations examined. The measurements were supported by electron micrographs of soil films which showed colonial growth covering soil particles. These findings suggest that Antarctica does not serve as a useful model for the Martian environment in evaluating quarantine standards.

Earth - Antarctica Mosaic

NASA Image and Video Library

1996-02-01

This color picture of the limb of the Earth, looking north past Antarctica, is a mosaic of 11 images taken during a ten-minute period near 5:45 p.m. PST Dec. 8, 1990, by NASA’s Galileo imaging system. http://photojournal.jpl.nasa.gov/catalog/PIA00116

Distributions of larval and juvenile/adult stages of the Antarctic myctophid fish, Electrona antarctica, off Wilkes Land in East Antarctica

NASA Astrophysics Data System (ADS)

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.

On the relation between SMMR 37-GHz polarization difference and the rainfall over Africa and Australia

NASA Technical Reports Server (NTRS)

Choudhury, Bhaskar J.; Digirolamo, Nicolo E.

1994-01-01

A major difficulty in interpreting coarse resolution satellite data in terms of land surface characteristics is unavailability of spatially and temporally representative ground observations. Under certain conditions rainfall has been found to provide a proxy measure for surface characteristics, and thus a relation between satellite observations and rainfall might provide an indirect approach for relating satellite data to these characteristics. Relationship between rainfall over Africa and Australia and 7-year average (1979-1985) polarization difference (PD) at 37 GHz from scanning multichannel microwave radiometer (SMMR) on board the Nimbus-7 satellite is studied in this paper. Quantitative methods have been used to screen (accept or reject) PD data considering antenna pattern, geolocation uncertainty, water contamination, surface roughness, and adverse effect of drought on the relation between rainfall and surface characteristics. The rainfall data used in the present analysis are climatologic averages and also 1979-1985 averages, and no screening has been applied to this data. The PD data has been screened considering only the location of rainfall stations, without any regard to rainfall amounts. The present analysis confirms a non-linear relation between rainfall and PD published previously.

A Novel Adenovirus in Chinstrap Penguins (Pygoscelis antarctica) in Antarctica

PubMed Central

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

2014-01-01

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. PMID:24811321

Petroleum and mineral resources of Antarctica

USGS Publications Warehouse

Kovar, Karel; Behrendt, John Charles

1983-01-01

No known petroleum or mineral resources occur in Antarctica. The data on these subjects have been collected, mainly since the IGY (International Geophysical Year), 1957-58, as a part of other research carried out by geologists and geophysicists from a number of countries. Specific resource-related studies have not been made. Wright and Williams (1974) summarized what was known of Antarctic mineral resources a decade ago.The U.S. Geological Survey has been actively pursuing various investigations in Antarctica since 194 7. In the course of this work and that of our colleagues elsewhere in the United States and in other countries, much information relevant to petroleum and mineral resources has been obtained. Since 1976, modern state-of-the-art multichannel seismic reflection and aeromagnetic surveys by several countries over the continental margin of Antarctica have indicated thick sedimentary basins. However, no offshore drilling beneath the continental shelf has taken place since the DSDP (Deep Sea Drilling Project) holes in the Ross Sea in 1973. Geologic field investigations begun at the turn of the twentieth century have been intensified in the past two decades; most rock outcrops have been visited and samples collected. Technology to exploit resources, particularly in the Arctic, has been developing at a rapid rate, and much of it could be applied to Antarctica. As a result of the petroleum price increases of the past decade, the attention of a number of countries has turned to Antarctica, but under the policy of "voluntary restraint" adopted by the Antarctic Treaty nations, no active petroleum or mineral exploration is taking place. The Antarctic treaty countries are in the process of negotiating an Antarctic mineral resources regime that is anticipated to be completed within the next several years. Therefore it seemed timely to us to readdress the question of petroleum and mineral resources. These reports review and summarize the available information. The

Epidemiologic and virologic assessment of the 2009 influenza A (H1N1) pandemic on selected temperate countries in the Southern Hemisphere: Argentina, Australia, Chile, New Zealand and South Africa

PubMed Central

Van Kerkhove, Maria D.; Mounts, Anthony W.; Mall, Sabine; Vandemaele, Katelijn A.H.; Chamberland, Mary; dos Santos, Thais; Fitzner, Julia; Widdowson, Marc‐Alain; Michalove, Jennifer; Bresee, Joseph; Olsen, Sonja J.; Quick, Linda; Baumeister, Elsa; Carlino, Luis O.; Savy, Vilma; Uez, Osvaldo; Owen, Rhonda; Ghani, Fatima; Paterson, Bev; Forde, Andrea; Fasce, Rodrigo; Torres, Graciela; Andrade, Winston; Bustos, Patricia; Mora, Judith; Gonzalez, Claudia; Olea, Andrea; Sotomayor, Viviana; Najera De Ferrari, Manuel; Burgos, Alejandra; Hunt, Darren; Huang, Q. Sue; Jennings, Lance C.; Macfarlane, Malcolm; Lopez, Liza D.; McArthur, Colin; Cohen, Cheryl; Archer, Brett; Blumberg, Lucille; Cengimbo, Ayanda; Makunga, Chuma; McAnerney, Jo; Msimang, Veerle; Naidoo, Dhamari; Puren, Adrian; Schoub, Barry; Thomas, Juno; Venter, Marietjie

2011-01-01

Please cite this paper as: Van Kerkhove et al. (2011) Epidemiologic and virologic assessment of the 2009 influenza A (H1N1) pandemic on selected temperate countries in the Southern Hemisphere: Argentina, Australia, Chile, New Zealand and South Africa. Influenza and Other Respiratory Viruses 5(6), e487–e498. Introduction and Setting  Our analysis compares the most comprehensive epidemiologic and virologic surveillance data compiled to date for laboratory‐confirmed H1N1pdm patients between 1 April 2009 ‐ 31 January 2010 from five temperate countries in the Southern Hemisphere–Argentina, Australia, Chile, New Zealand, and South Africa. Objective  We evaluate transmission dynamics, indicators of severity, and describe the co‐circulation of H1N1pdm with seasonal influenza viruses. Results  In the five countries, H1N1pdm became the predominant influenza strain within weeks of initial detection. South Africa was unique, first experiencing a seasonal H3N2 wave, followed by a distinct H1N1pdm wave. Compared with the 2007 and 2008 influenza seasons, the peak of influenza‐like illness (ILI) activity in four of the five countries was 3‐6 times higher with peak ILI consultation rates ranging from 35/1,000 consultations/week in Australia to 275/100,000 population/week in New Zealand. Transmission was similar in all countries with the reproductive rate ranging from 1.2–1.6. The median age of patients in all countries increased with increasing severity of disease, 4–14% of all hospitalized cases required critical care, and 26–68% of fatal patients were reported to have ≥1 chronic medical condition. Compared with seasonal influenza, there was a notable downward shift in age among severe cases with the highest population‐based hospitalization rates among children <5 years old. National population‐based mortality rates ranged from 0.8–1.5/100,000. Conclusions  The difficulty experienced in tracking the progress of the pandemic globally, estimating

Live from Antarctica: Then and now

NASA Astrophysics Data System (ADS)

This real-time educational video series, featuring Camille Jennings from Maryland Public Television, includes information from Antarctic scientists and interactive discussion between the scientists and school children from both Maryland and Hawaii. This is part of a 'Passport to Knowledge Special' series. In this part of the four part Antarctic series, the history of Antarctica from its founding to the present, its mammals, plants, and other life forms are shown and discussed. The importance of Antarctica as a research facility is explained, along with different experiments and research that the facilities there perform.

Live from Antarctica: Then and Now

NASA Technical Reports Server (NTRS)

1994-01-01

This real-time educational video series, featuring Camille Jennings from Maryland Public Television, includes information from Antarctic scientists and interactive discussion between the scientists and school children from both Maryland and Hawaii. This is part of a 'Passport to Knowledge Special' series. In this part of the four part Antarctic series, the history of Antarctica from its founding to the present, its mammals, plants, and other life forms are shown and discussed. The importance of Antarctica as a research facility is explained, along with different experiments and research that the facilities there perform.

Foreign-born aged care workers in Australia: A growing trend.

PubMed

Negin, Joel; Coffman, Jenna; Connell, John; Short, Stephanie

2016-12-01

To address Australian aged care workforce challenges, a deeper understanding of the current care workforce is needed especially given estimated increases in demand. We provide a national picture of the aged care workforce in Australia focusing on country of birth. Data from the 2006 and 2011 Australian censuses. The majority of care workers are Australia-born followed by those born in the United Kingdom, South-East Asia and South Asia. While the number of carers from all regions has grown, the increase from 2006 to 2011 has been highest for carers from South Asia (333% increase) and sub-Saharan Africa (145%). The state with the largest decrease in the proportion of Australian-born care workers is Western Australia where Australian-born workers dropped from 62% in 2006 to 49% in 2011. Understanding the migration patterns of the aged care workforce in Australia is critical to health workforce planning given increasing demand. © 2016 AJA Inc.

Psychrotolerant anaerobes from Lake Podprudnoye, Antarctica and penguin Spheniscus demersus colony, South Africa

NASA Astrophysics Data System (ADS)

Guisler, Melissa; Pikuta, Elena V.; Townsend, Alisa; Hoover, Richard B.

2009-08-01

The study of a sample collected from a wind-made ice sculpture near Lake Podprudnoe, Antarctica led to the isolation of the psychrotolerant strain ISLP-3. Cells of the new isolate are vibrio-shaped that measure 0.5 x 1.0-3.0 μm in size. Growth occurs within the temperature range 5-35ºC with the optimum at 22 °C. Salinity range for growth is 0-2 % NaCl with the optimum at 0.25 %. The new isolate grows within a pH range from 6.0 to 9.5 with the optimum at 7.5. Strain ISLP-3 is saccharolytic, growing on the following substrates: D-glucose, D-ribose, D-fructose, D-arabinose, maltose, sucrose, D-trehalose, D-mannose, D-cellobiose, lactose, starch, chitin, triethylamine, N-acetylglucosamine, and urea. The best growth occurred on D-cellobiose. An environmental sample of pond water near a colony of the endemic species of African penguins, Spheniscus demersus, was collected in February 2008 and delivered directly to the Astrobiology laboratory at NSSTC. The microbiological study of this sample led to the isolation of two psychrotolerant strains ARHSd-7G and ARHSd-9G. Both strains are strictly anaerobic bacteria and are able to grow at high pH and low temperatures. The cells of strain ARHSd-7G are motile, vibrio-shaped, spore-forming cells. Optimal growth of this strain occurs at 30 ºC, 3 % NaCl, and pH 8.9. The isolate ARHSd-7G combines sugarlytic and proteolytic metabolisms, growing on some proteolysis products including peptone and yeast extract and a number of sugars. The second isolate, ARHSd-9G, exhibits thin, elongated rods that measure 0.4 x 3-5 μm. The cells are motile and spore-forming. Optimal growth of strain ARHSd-9G occurs at 30 ºC, 1.75 % NaCl, and pH 8.5. The strain ARHSd-9G is sugarlytic, growing well on substrates such as D-glucose, sucrose, D-cellobiose, maltose, fructose, D-mannose, and trehalose (the only exception is positive growth on yeast extract). In this report, the physiological and morphological characteristics of the novel

New Genetic and Linguistic Analyses Show Ancient Human Influence on Baobab Evolution and Distribution in Australia

PubMed Central

Rangan, Haripriya; Bell, Karen L.; Baum, David A.; Fowler, Rachael; McConvell, Patrick; Saunders, Thomas; Spronck, Stef; Kull, Christian A.; Murphy, Daniel J.

2015-01-01

This study investigates the role of human agency in the gene flow and geographical distribution of the Australian baobab, Adansonia gregorii. The genus Adansonia is a charismatic tree endemic to Africa, Madagascar, and northwest Australia that has long been valued by humans for its multiple uses. The distribution of genetic variation in baobabs in Africa has been partially attributed to human-mediated dispersal over millennia, but this relationship has never been investigated for the Australian species. We combined genetic and linguistic data to analyse geographic patterns of gene flow and movement of word-forms for A. gregorii in the Aboriginal languages of northwest Australia. Comprehensive assessment of genetic diversity showed weak geographic structure and high gene flow. Of potential dispersal vectors, humans were identified as most likely to have enabled gene flow across biogeographic barriers in northwest Australia. Genetic-linguistic analysis demonstrated congruence of gene flow patterns and directional movement of Aboriginal loanwords for A. gregorii. These findings, along with previous archaeobotanical evidence from the Late Pleistocene and Holocene, suggest that ancient humans significantly influenced the geographic distribution of Adansonia in northwest Australia. PMID:25830225

Plate tectonics, seaways and climate in the historical biogeography of mammals.

PubMed

Cox, C B

2000-01-01

The marsupial and placental mammals originated at a time when the pattern of geographical barriers (oceans, shallow seas and mountains) was very different from that of today, and climates were warmer. The sequence of changes in these barriers, and their effects on the dispersal of the mammal families and on the faunas of mammals in the different continents, are reviewed. The mammal fauna of South America changed greatly in the Pliocene/Pleistocene, when the newly-complete Panama Isthmus allowed the North American fauna to enter the continent and replace most of the former South American mammal families. Marsupial, but not placental, mammals reached Australia via Antarctica before Australia became isolated, while rats and bats are the only placentals that dispersed naturally from Asia to Australia in the late Cenozoic. Little is known of the early history of the mammal fauna of India. A few mammal families reached Madagascar from Africa in the early Cenozoic over a chain of islands. Africa was isolated for much of the early Cenozoic, though some groups did succeed in entering from Europe. Before the climate cooled in the mid-Cenozoic, the mammal faunas of the Northern Hemisphere were much richer than those of today.

Livistona palms in Australia: ancient relics or opportunistic immigrants?

PubMed

Crisp, Michael D; Isagi, Yuji; Kato, Yohei; Cook, Lyn G; Bowman, David M J S

2010-02-01

Eighteen of the 34 species of the fan palm genus Livistona (Arecaceae) are restricted to Australia and southern New Guinea, east of Wallace's Line, an ancient biogeographic boundary between the former supercontinents Laurasia and Gondwana. The remaining species extend from SE Asia to Africa, west of Wallace's Line. Competing hypotheses contend that Livistona is (a) ancient, its current distribution a relict of the supercontinents, or (b) a Miocene immigrant from the north into Australia as it drifted towards Asia. We have tested these hypotheses using Bayesian and penalized likelihood molecular dating based on 4Kb of nuclear and chloroplast DNA sequences with multiple fossil calibration points. Ancestral areas and biomes were reconstructed using parsimony and maximum likelihood. We found strong support for the second hypothesis, that a single Livistona ancestor colonized Australia from the north about 10-17Ma. Spread and diversification of the genus within Australia was likely favoured by a transition from the aseasonal wet to monsoonal biome, to which it could have been preadapted by fire-tolerance. Copyright (c) 2009 Elsevier Inc. All rights reserved.

Antarctica, supercontinents and the palaeogeography of the Cambrian 'explosion'

NASA Astrophysics Data System (ADS)

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

Cryoconite and Ice-bubble Microbial Ecosystems in Antarctica

NASA Technical Reports Server (NTRS)

Hoover, Richard B.; Rose, M. Franklin (Technical Monitor)

2000-01-01

During the Antarctica 2000 Expedition samples of rocks and ice bubbles entrained in ice were collected from the blue ice fields near the Moulton Escarpment of the Thiel Mountains (85S, 94W) and the Morris Moraine of the Patriot Hills (80S, 8 1 W) Ellsworth Mountains of Antarctica. Investigation of the microbiota of these cryoconite and ice bubble ecosystems are now being conducted to help refine chemical and morphological biomarkers of potential significance to Astrobiology. The Antarctica 2000 Expedition will be discussed and the preliminary results of the studies of the ice bubble and cryoconite microbial ecosystems discussed. Recent ESEM images of the Antarctic microbiota will be presented a the relevance of ice ecosystems to Astrobiology will be discussed.

Sociocultural Influences on Psychosocial Adjustment in Antarctica

DTIC Science & Technology

1985-12-01

od-; SOCIOCULTURAL INFLUENCES ON PSYCHOSOCIAL ADJUSTMENT IN ANTARCTICA L. A. PALINKAS 00 00 ’n REPORT NO. 85-49 D I MAR ~3 11986 L) L O~flN STAnTEMN...A Apprtoved 6Wz PUbli reIl. NAVAL HEALTH RESEARCH CENTER P.O. BOX 85122 0 SAN DIEGO, CALIFORNIA 92138-9174 --j NAVAL MEDICAL RESEARCH AND DEVELOPMENT ...COMMAND LJ6. BETHESDA, MARYLAND SOCIOCULTURAL INFLUENCES ON PSYCHOSOCIAL ADJUSTMENT IN ANTARCTICA Lawrence A. Palinkas, Ph.D. Manager, Psychiatric

Seismic Constraints on the Mantle Viscosity Structure beneath Antarctica

NASA Astrophysics Data System (ADS)

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

Characteristics of atmospheric transport into the Antarctic troposphere

NASA Astrophysics Data System (ADS)

Stohl, A.; Sodemann, H.

2010-01-01

We have developed a 5.5 year climatology of atmospheric transport into the Antarctic troposphere, which uses the same data set and methods as described in a recent study for the Arctic. This allows direct comparisons of transport properties for the two polar regions. The climatology is based on a simulation with the Lagrangian particle dispersion model FLEXPART, where the model atmosphere was globally filled with particles. Transport characteristics as well as emission sensitivities were derived from 6 hourly particle positions. We found that the probability for near-surface air to originate from the stratosphere on a time scale of 10 days is an order of magnitude higher near the South Pole than near the North Pole, a result of higher topography and descent that partly compensates for the flow of air down the Antarctic Plateau with the katabatic winds. The stratospheric influence is largest in fall, which is opposite to the seasonality in the Arctic. Stratospheric influence is much smaller over the shelf ice regions and in a band around Antarctica. The average time for which air near the surface has been exposed to continuous darkness in July (continuous light in January) is longest over the Ronne Ice Shelf and Ross Ice Shelf at ˜11 days (20 days). We calculated how sensitive Antarctic air masses are to emission input up to 30 days before arriving in Antarctica if removal processes are ignored. The emission sensitivity shows strong meridional gradients and, as a result, is generally low over South America, Africa, and Australia. For a 10 day time scale, the largest emission sensitivities over these continents are 1-2 orders of magnitude smaller than over Eurasia for transport to the Arctic, showing that foreign continents have a much smaller potential to pollute the Antarctic than the Arctic troposphere. Emission sensitivities and derived black carbon (BC) source contributions over South America, Africa, and Australia are substantially (a factor 10 for Africa

In Situ Observational Constraints on GIA in Antarctica

NASA Astrophysics Data System (ADS)

Wilson, T. J.; Bevis, M. G.; Kendrick, E. C.; Konfal, S.; Dalziel, I. W.; Smalley, R.; Willis, M. J.; Wiens, D. A.; Heeszel, D. S.

2012-12-01

Geodetic and seismologic data sets have been acquired across a significant portion of Antarctica through deployment of autonomous, remote instrumentation by the Antarctic Network (ANET) project of the Polar Earth Observing Network (POLENET). Continuous GPS measurements of bedrock crustal motions are yielding a synoptic picture of vertical and horizontal crustal motion patterns from the Transantarctic Mountains to the Ellsworth-Whitmore Mountains and Marie Byrd Land regions. Vertical motion patterns are broadly compatible with predictions from current GIA models, but the magnitudes of the vertical motions are substantially lower than predicted. Slower rates of uplift due to GIA can be attributed to factors including errors in ice history, a superposed solid earth response to modern ice mass change, and/or the influence of laterally varying earth properties on the GIA response. Patterns of horizontal motions measured by ANET show that the role of laterally varying earth rheology is extremely important in Antarctica. Crustal motion vectors are closely aligned and document motion from East toward West Antarctica, in contradiction to ice sheet reconstructions placing maximum LGM ice mass loss in West Antarctica and GIA models that predict motions in the opposite direction. When compared to earth structure mapped by seismology, the horizontal crustal motions are consistently near-perpendicular to the very strong gradient in crust and mantle properties, perhaps the first confirmation of predictions from modeling studies that horizontal motions can be deflected or even reversed where such a lateral earth property exists. Accurate GIA models for Antarctica clearly require a laterally-varying earth model and tuning based on these new GPS and seismological constraints.

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

Code of Federal Regulations, 2010 CFR

2010-10-01

... 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. ...

Autumn Cooling of Western East Antarctica Linked to the Tropical Pacific

NASA Astrophysics Data System (ADS)

Clem, Kyle R.; Renwick, James A.; McGregor, James

2018-01-01

Over the past 60 years, the climate of East Antarctica cooled while portions of West Antarctica were among the most rapidly warming regions on the planet. The East Antarctic cooling is attributed to a positive trend in the Southern Annular Mode (SAM) and a strengthening of the westerlies, while West Antarctic warming is tied to zonally asymmetric circulation changes forced by the tropics. This study finds recent (post-1979) surface cooling of East Antarctica during austral autumn to also be tied to tropical forcing, namely, an increase in La Niña events. The recent increase in La Niña conditions forces a Rossby wave into the Southern Hemisphere that increases anticyclonic circulation over the South Atlantic. The South Atlantic anticyclone is associated with cold air advection, weakened northerlies, and increased sea ice concentrations across the western East Antarctic coast, which has increased the rate of cooling at Novolazarevskaya and Syowa stations after 1979. This enhanced cooling over western East Antarctica is tied more broadly to a zonally asymmetric temperature trend pattern across East Antarctica during autumn that is consistent with a tropically forced Rossby wave rather than a SAM pattern; the positive SAM pattern is associated with ubiquitous cooling across East Antarctica, which is not seen in temperature observations after 1979. We conclude that El Niño-Southern Oscillation-related circulation anomalies, particularly zonal asymmetries that locally enhance meridional wind, are an important component of East Antarctic climate variability during autumn, and future changes in tropical Pacific climate will likely have implications for East Antarctica.

The Meteoritical Bulletin, No. 96, September 2009

USGS Publications Warehouse

Weisberg, M.K.; Smith, C.; Benedix, G.; Herd, C.D.K.; Righter, K.; Haack, H.; Yamaguchi, A.; Chennaoui, Aoudjehane H.; Grossman, J.N.

2009-01-01

The Meteoritical Bulletin No. 96 contains a total of 1590 newly approved meteorite names with their relevant data. These include 12 from specific locations within Africa, 76 from northwest Africa, 9 from the Americas, 13 from Asia, 1 from Australia, 2 from Europe, 950 from Antarctica recovered by the Chinese Antarctic Research Expedition (CHINARE), and 527 from the American Antarctic program (ANSMET). Among these meteorites are 4 falls, Almahata Sitta (Sudan), Sulagiri (India), Ash Creek (United States), and Maribo (Denmark). Almahata Sitta is an anomalous ureilite and is debris from asteroid 2008 TC3 and Maribo is a CM2 chondrite. Other highlights include a lunar meteorite, a CM1 chondrite, and an anomalous IVA iron. ?? The Meteoritical Society, 2009.

Culturally Appropriate Mentoring for Horn of African Young People in Australia

ERIC Educational Resources Information Center

Griffiths, Megan; Sawrikar, Pooja; Muir, Kristy

2009-01-01

Little is known about how to appropriately adapt mentoring programs for young people from the Horn of Africa, even though they have been arriving in Australia in significantly increasing numbers. These young people face unique challenges as a result of their age, ethnicity, migration and direct/indirect trauma experiences. The results of this…

Antarctica: Discovery & Exploration.

ERIC Educational Resources Information Center

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)…

The Impact of Iron Limitation on Remote Sensing Reflectance in Phaeocystis antarctica

NASA Astrophysics Data System (ADS)

Tagliabue, A.; van Dijken, G. L.; Arrigo, K. R.

2006-12-01

The iron limited Southern Ocean is an important controller of the global carbon cycle and is predicted to be heavily impacted by future changes in climate. Such remote regions are heavily reliant on acquiring data from remotely sensed satellite observations of pigment concentrations, via algorithms that utilize bio-optical properties to estimate chlorophyll a concentrations. The haptophyte Phaeocystis antarctica is a key phytoplankton functional group across the Southern Ocean and dominates phytoplankton biomass in the highly productive southwestern Ross Sea. In this study, we examine absorption spectra obtained from laboratory cultures of P. antarctica grown under iron sufficient and deficient conditions. We then utilize a semi-analytical reflectance model, alongside data collected from the Ross Sea, to compare remote sensing reflectance (Rrs) derived from absorption spectra to chlorophyll a. We find that Rrs(490):Rrs(555) per unit chlorophyll a for iron sufficient P. antarctica is consistent with the existing Ross Sea algorithm. However, the increased chlorophyll specific absorption at 490 and 555 nm of iron deficient P. antarctica results in a reduction in Rrs(490):Rrs(555) per unit chlorophyll a. Therefore, remotely sensed chlorophyll a concentrations based on Rrs(490):Rrs(555) will be overestimated when waters dominated by P. antarctica experience iron stress. If remotely sensed chlorophyll a concentrations are erroneously high when P. antarctica is iron limited, then both the magnitude and duration of P. antarctica blooms might have been overestimated. We suggest that an in situ investigation of the P. antarctica Rrs to chlorophyll a relationship is necessary during the onset of iron limitation. The likely causes and broader implications of these conclusions will also be discussed.

The Ilgarijiri Project: A collaboration between Aboriginal communities and radio astronomers in the Murchison Region of Western Australia

NASA Astrophysics Data System (ADS)

Goldsmith, John

2014-07-01

The international radio astronomy initiative known as the Square Kilometre Array is a cutting-edge science project, aimed atdramatically expanding our vision and understanding of the Universe. The $2billion+ international project is being shared between Southern Africa and Australia. The Australian component, centred in the Murchison region of Western Australia, is based upon collaboration with Aboriginal communities. A collaborative project called "Ilgarijiri- Things Belonging to the Sky" shared scientific and Aboriginal knowledge of the night sky. Through a series of collaborative meetings and knowledge sharing, the Ilgarijiri project developed and showcased Aboriginal knowledge of the night sky, via an international touring Aboriginal art exhibition, in Australia, South Africa, the USA and Europe. The Aboriginal art exhibition presents Aboriginal stories relating to the night sky, which prominently feature the 'Seven Sisters' and the 'Emu', as well as the collaborative experience with radio astronomers. The success of the Ilgarijiri collaborative project is based upon several principles, which can help to inform and guide future cultural collaborative projects.

The mantle transition zone beneath Antarctica: Evidence for thermal upwellings and hydration

NASA Astrophysics Data System (ADS)

Nyblade, Andrew; Emry, Erica; Hansen, Samantha; Julia, Jordi; Anandakrishnan, Sridhar; Aster, Richard; Wiens, Douglas; Huerta, Audrey; Wilson, Terry

2015-04-01

West Antarctica has experienced abundant Cenozoic volcanism, and it is suspected that the region is influenced by upwelling thermal plumes from the lower mantle; however this has not yet been verified, because seismic tomography results are not well resolved at mantle transition zone (MTZ) depths. We use P-wave receiver functions (PRFs) from temporary and permanent arrays throughout Antarctica, including the Antarctic POLENET, TAMNET, TAMSEIS, and GAMSEIS arrays, to explore the characteristics of the MTZ beneath the continent. We obtained PRFs for earthquakes occurring at 30-90° with Mb>5.5 using a time-domain iterative deconvolution method filtered with a Gaussian-width of 0.5 and 1.0, corresponding to frequencies less than ~0.24 Hz and ~0.48 Hz, respectively. We combine P receiver functions as single-station and as common conversion point stacks and migrate them to depth using the ak135 1-d velocity model. Results from West Antarctica suggest that the thickness of the MTZ varies throughout the region with thinning beneath the Ruppert Coast of Marie Byrd Land and beneath the Bentley Subglacial Trench and Whitmore Mountains. Also, prominent negative peaks are detected above the transition zone beneath much of West Antarctica and may be evidence for water-induced partial melt above the MTZ. Preliminary results from single-station stacks for the mantle transition zone beneath East Antarctica suggests that one section of East Antarctica, off of the South Pole may have slightly thinned transition zone. Results are forthcoming from the mantle transition zone beneath Victoria Land and the Northern Transantarctics. We propose that the MTZ beneath parts of West Antarctica and possibly also beneath one region of East Antarctica, is hotter than average, possibly due to material upwelling from the lower mantle. Furthermore, we propose that the transition zone beneath much of West Antarctica is water-rich and that upward migration of hydrated material results in formation of

A reference model for crust and uppermost mantle beneath Antarctica

NASA Astrophysics Data System (ADS)

Shen, W.; Wiens, D.; Gerstoft, P.; Bromirski, P. D.; Stephen, R. A.; Aster, R. C.; Nyblade, A.; Winberry, J. P.; Huerta, A. D.; Anandakrishnan, S.; Hansen, S. E.; Wilson, T. J.; Heeszel, D.

2016-12-01

Since the last decade of the 20th Century, over 300 broad-band seismic stations have been deployed across the continent of Antarctica (e.g., temporary networks such as TAMSEIS, AGAP/GAMSEIS, POLENET/ANET, TAMNNET and RIS/DRIS by US geoscientists, as well as stations deployed by other countries). In this presentation, we discuss our recent effort that builds a reference crustal and uppermost mantle shear velocity (Vs) model for continental Antarctica based on those seismic arrays. The data analysis for this effort consists of four steps. First, we compute ambient noise cross-correlations between all possible station pairs and use them to construct Rayleigh wave phase and group velocity maps at a continental scale. Coherence of the new maps with maps generated from teleseismic earthquake data from an earlier study (Heeszel et al., 2016) confirms the high quality of both maps and the minor difference helps quantify the map uncertainties. Second, we compute P receiver function waveforms for each station in Antarctica. Third, we collect Rayleigh waves generated by teleseismic earthquakes and measure their horizontal to vertical (H/V) ratio at each station. Fourth and finally, by combing all seismic measurements from the first three steps together with the phase velocity maps by Heeszel et al.(2016) using a non-linear Monte Carlo (MC) inversion algorithm, we built a 3-D model for the crust and uppermost mantle beneath continental Antarctica and its periphery to a depth of 150 km. This high resolution model, together with associated uncertainty estimates from the MC inversion, serve as a starting point for further improvement and geological interpretation. A variety of tectonic features, including a slower but highly heterogeneous West Antarctica and a much faster East Antarctica, are present in the 3D model. A better image of these features from the 3D model helps further investigation of the thermal and dynamic state of Antarctica's lithosphere and underlying

Urinary excretion of adrenal steroids, catecholamines and electrolytes in man, before and after acclimatization to cold in Antarctica

PubMed Central

Budd, G. M.; Warhaft, N.

1970-01-01

1. Urine samples were collected from four men before and during test cold exposures in Melbourne, Australia, and Mawson, Antarctica. Changes in the response of body temperature to the test exposures showed that the men had acclimatized to cold at Mawson. 2. Excretion rates of 17-hydroxycorticosteroids and 17-ketosteroids were significantly greater at Mawson than in Melbourne, in both the pre-exposure and exposure periods. 3. Excretion rates of noradrenaline, adrenaline, sodium, potassium and creatinine did not differ significantly between Mawson and Melbourne, nor did urine flow rates. 4. During the cold exposure significant increases occurred, to the same extent at Mawson as in Melbourne, in urine flow rate and in all measured urinary constituents except creatinine. PMID:5501486

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

NASA Astrophysics Data System (ADS)

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.

The future of space - Space tomorrow: The Antarctica model

NASA Technical Reports Server (NTRS)

Beggs, J.

1983-01-01

The exploration and settling of Antarctica with permanent bases are used as illustrative points for establishing a permanent human presence in near-earth space. NASA activities since 1958 have spawned the computer science, solid-state electronics, medical electronics, and communications satellites industries, which are also rapidly expanding in other countries, as are space-faring capabilities. Antarctica is a paradigm for space exploration in that it is hard to reach, hostile to human life, and a great amount of planning is necessary to arrive at the destination and survive. Aircraft made permanent settlements possible on Antarctica, just as the Shuttle does for space. A space station would provide the remote base from which exploration of other planets and settling on the moon could proceed.

Pituitary-gonadal hormones during prolonged residency in Antarctica.

PubMed

Sawhney, R C; Malhotra, A S; Prasad, R; Pal, K; Kumar, R; Bajaj, A C

1998-08-01

Plasma luteinizing hormone (LH), follicle stimulating hormone (FSH), prolactin (PRL) and testosterone levels were measured in nine eugonadal men in New Delhi and during the 1st week of different months of their stay at Dakshin Gangotri in Antarctica. During their 12-month stay in Antarctica, they were exposed to a severely cold climate, long polar nights and polar days, high wind velocity, increased amounts of solar and ultraviolet radiation and geomagnetism, as well as physical and social isolation. Plasma testosterone tended to increase in March, but a significant increase (P < 0.05) was not seen until April. The mean testosterone levels in May, June, September and November were also significantly higher than the March or New Delhi values. The absolute values of LH, FSH and PRL did not show any month-to-month changes in Antarctica. However, when the hormone levels were expressed as a percentage of the individual annual Antarctic mean, significant differences as a percentage of the individual annual Antarctic mean, significant differences were observed. The testosterone peak in April, May and June was associated with an increase in LH. The nadirs of testosterone, LH, FSH and PRL were seen in either July or August. FSH showed the highest values in March, whereas the highest PRL values were seen in November. These observations suggest the presence of circannual variations in gonadotropin, PRL and LH in Antarctica which are independent of polar days and polar nights. It appears that factors other than the duration of daylight might be involved in regulating these changes. The significance of maintenance of testosterone levels in the supra-physiological range in Antarctica remains unknown but may be important in acclimatization/habituation to the extreme polar cold by increasing basal metabolic rate, protein synthesis and erythropoiesis.

Airborne geophysical study in the pensacola mountains of antarctica

USGS Publications Warehouse

Behrendt, John C.; Meister, L.; Henderson, J.R.

1966-01-01

A seismic reflection, gravity, and aeromagnetic reconnaissance was made in the Pensacola Mountains, Antarctica, during the 1965-66 austral summer. Prominent ice streams located between the Neptune and Patuxent Ranges and east of the Forrestal Range overlie channels in the rock surface 2000 meters below sea level which are probably of glacial origin. Seismic reflections show that the Filchner Ice Shelf is 1270 meters thick near its southern margin. Along the boundary between West and East Antarctica, Bouguer anomalies decrease from +60 milligals in West Antarctica to -80 milligals in East Antarctica. An abrupt change in crustal structure across this boundary is required to explain the 2 milligals per kilometer gradient. This may indicate a fault extending through the crust into the mantle. Aeromagnetic profiles delineate anomalies up to 1800 ?? associated with the basic stratiform intrusion which comprises the Dufek and Forrestal ranges. A probable minimum area of 9500 square kilometers is calculated for the intrusive body on the basis of the magnetic anomalies, making it one of the largest bodies of its type. The extension of this magnetic anomaly across a fault forming the north border of the Pensacola Mountains probably precludes transcurrent movement.

Airborne geophysical study in the pensacola mountains of antarctica.

PubMed

Behrendt, J C; Meister, L; Henderson, J R

1966-09-16

A seismic reflection, gravity, and aeromagnetic reconnaissance was made in the Pensacola Mountains, Antarctica, during the 1965-66 austral summer. Prominent ice streams located between the Neptune and Patuxent Ranges and east of the Forrestal Range overlie channels in the rock surface 2000 meters below sea level which are probably of glacial origin. Seismic reflections show that the Filchner Ice Shelf is 1270 meters thick near its southern margin. Along the boundary between West and East Antarctica, Bouguer anomalies decrease from +60 milligals in West Antarctica to -80 milligals in East Antarctica. An abrupt change in crustal structure across this boundary is required to explainl the 2 milligals per kilometer gradient. This may indicate a fault extending through the crust into the mantle. Aeromagnetic profiles delineate anomalies up to 1800 gamma associated with the basic stratiform intrusion which comprises the Dufek and Forrestal ranges. A probable minimum area of 9500 square kilometers is calculated for the intrusive body on the basis of the magnetic anomalies, making it one of the largest bodies of its type. The extension of this magnetic anominaly across a fault forming the north border of the Pensacola Mountains probably precludes transcurrent movement.

The Meteoritical Bulletin, no. 85, 2001 September

USGS Publications Warehouse

Grossman, J.N.; Zipfel, J.

2001-01-01

Meteoritical Bulletin No. 85 lists information for 1376 newly classified meteorites, comprising 658 from Antarctica, 409 from Africa, 265 from Asia (262 of which are from Oman), 31 from North America, 7 from South America, 3 from Australia, and 3 from Europe. Information is provided for 11 falls (Dergaon, Dunbogan, Gujba, Independence, Itqiy, Mora??vka, Oued el Hadjar, Sayama, Sologne, Valera, and Worden). Noteworthy non-Antarctic specimens include 5 martian meteorites (Dar al Gani 876, Northwest Africa 480 and 817, and Sayh al Uhaymir 051 and 094); 6 lunar meteorites (Dhofar 081, 280, and 287, and Northwest Africa 479, 482, and 773); an ungrouped enstatite-rich meteorite (Itqiy); a Bencubbin-like meteorite (Gujba); 9 iron meteorites; and a wide variety of other interesting stony meteorites, including CH, CK, CM, CO, CR, CV, R, enstatite, and unequilibrated ordinary chondrites, primitive achondrites, HED achondrites, and ureilites.

Another bipolar deep-sea anemone: new species of Iosactis (Actiniaria, Endomyaria) from Antarctica

NASA Astrophysics Data System (ADS)

Rodríguez, Estefanía

2012-06-01

A new species of deep-sea burrowing sea anemone is described and illustrated from Antarctica. Iosactis antarctica sp. nov. is characterised by easily deciduous tentacles with sphincters in the base, smooth column, endodermal marginal sphincter, same mesenteries proximally and distally, 24 perfect mesenteries regularly arranged, diffuse retractor musculature and basilar muscles well developed. Iosactis antarctica sp. nov. is the second species of the deep-sea abyssal genus Iosactis; it differs from I. vagabunda in internal anatomy, cnidae and geographic distribution. The description of I. antarctica sp. nov. provides the opportunity to revaluate the morphology of the proximal end of this genus.

Are Deschampsia antarctica Desv. and Colobanthus quitensis (Kunth) Bartl. migratory relicts?

PubMed

Parnikoza, I Yu; Maidanuk, D N; Kozeretska, I A

2007-01-01

It remains unclear why there are only two vascular plant species in Antarctica, Deschampsia antarctica Desv. (Poaceae) and Colobanthus quitensis (Kunth) Bartl. (Caryophyllaceae). Despite progressing climate warming, there is also just one alien plant species found in the region, introduced by humans and spreading mainly in disturbed habitats. In the present article we try to interpret the data concerning the history of the biota and glaciations of the continent, proceeding from the assumption that both plants migrated to Antarctica during the Oligocene-Pliocene, when it was less isolated and the climate was more favorable for their naturalization. Genetic evidence was also taken into consideration. Our data allow suggesting secondary dispersal in the region, due to transfer by birds with regard of climate changes. With this in mind, we believe that D. antarctica and C. quitensis are migratory relicts.

Getting Antarctica down Cold!

ERIC Educational Resources Information Center

Sandmeier, Kay; Greeson, Linda

1990-01-01

Outlines learning activities for applying geography's five fundamental themes to studying Antarctica and points out the learning potential, for studying the economic, historical, and political geography of the continent. Groups activities for grades K-5, 6-8, and 8-12. Stresses cooperative learning in general, and includes a role play activity for…

Antarctica: a review of recent medical research.

PubMed

Olson, James J

2002-10-01

This article reviews recent developments and areas of research in Antarctic medical science. Nineteen nations are part of the Antarctic treaty and undertake research programmes in Antarctica. Medical science is a small but important part of these programmes. Areas that have been studied include aspects of cold physiology, ultraviolet light effects, endocrine changes (including polar T3 syndrome), alterations in immune function, chronobiology, psychology, microbiology, epidemiology and telemedicine. Antarctica has been recognized as the closest thing on Earth to a testing ground for aspects of space exploration and as such has been termed a space analogue.

Earth - Ross Ice Shelf, Antarctica

NASA Image and Video Library

1996-02-09

This color picture of Antarctica is one part of a mosaic of pictures covering the entire Antarctic continent taken during the hours following NASA's Galileo historic first encounter with its home planet. http://photojournal.jpl.nasa.gov/catalog/PIA00117

Live from Antarctica: the Coldest, Windiest Place on Earth

NASA Technical Reports Server (NTRS)

1994-01-01

In this first part of a four part 'Passport to Knowledge Special', hosted by Camille Jennings from Maryland Public Television, children from Maryland and Texas schools had the opportunity to directly interact with and ask questions of scientists and researchers in Antarctica live. The physical characteristics of Antarctica are featured, along with their effects on the human and microbiological organisms living in the region. The reasons behind the clothing worn in the Antarctic and the importance of the meteorological station are featured. Interviews with Professor Ian Dolziel (U of Texas) and Lt. commander John Joseph, NSFA (the head of the Navy Meteorology Center) occur with the school children, along with actual video footage of the surrounding geological features and geography. The 'Weatherops' is located at McMurdo Station, Antarctica.

Live from Antarctica: The coldest, windiest place on Earth

NASA Astrophysics Data System (ADS)

In this first part of a four part 'Passport to Knowledge Special', hosted by Camille Jennings from Maryland Public Television, children from Maryland and Texas schools had the opportunity to directly interact with and ask questions of scientists and researchers in Antarctica live. The physical characteristics of Antarctica are featured, along with their effects on the human and microbiological organisms living in the region. The reasons behind the clothing worn in the Antarctic and the importance of the meteorological station are featured. Interviews with Professor Ian Dolziel (U of Texas) and Lt. commander John Joseph, NSFA (the head of the Navy Meteorology Center) occur with the school children, along with actual video footage of the surrounding geological features and geography. The 'Weatherops' is located at McMurdo Station, Antarctica.

Colony Size of Phaeocystis Antarctica (Prymnesiophyceae) as Influenced by Zooplankton Grazers

EPA Science Inventory

The haptophyte Phaeocystis antarctica is a dominant phytoplankton species in the Ross Sea, Antarctica, and exists as solitary cells and mucilaginous colonies that differ by several orders of magnitude in size. Recent studies with P. globosa suggested that colony formation and enl...

Occurrence and diversity of marine yeasts in Antarctica environments

NASA Astrophysics Data System (ADS)

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.

Humus in some soils from Western Antarctica

NASA Astrophysics Data System (ADS)

Abakumov, E.

2009-04-01

Soils of Antarctica are well known as a thick profile soils with low amounts of humus concentrated in the upper layers - O or A horizons. Also there are specific soils of seashore landscapes which affected by penguins guano accumulation and, therefore characterized by high stocks of organic matter in solum. These two types of soils were studied during the Western Antarctica part of 53th Russian Antarctic Expedition in 2008 International Polar Year. These rote of expedition was on Polar stations "Russkaya", "Leningradskaya" and "Bellinsgausen" and also two places, not affected by polar men's - Lindsey Island and Hudson mountains (Ross Sea). Typical soils of "Russkaya" and "Leningradskaya" stations was a Cryosoils with low humus content (0,02 - 0,20 %) which was a product of lichens decaying and further humification. The humus profile was not deep and humic substances migration stopped on the 30 cm deeps maximally. Soils of Sub-Antarctica (Bellinsgausen station, King-George Island) show higher portions of humus which maximum was 3,00 % under the mosses. Humus distribution was more gradual through profile due to the higher thickness of active layer and longer period of biological activity. Soils under the penguin's beaches shows big portions of organic matter, in some cases more than 50 % to total soil mass. Humification starts in first years in cases of Sub-Antarctic guano soils and only after 3-7 years of leaching in seashore Antarctic guano-soils. Soils under the guano layers were extremely reached by nitrogen, and in some cases there were not any plants there due to toxicity of guano. This event was more typical for cold seashore soils of Antarctica. In all cases humus consists mostly of fulvic acids and low molecular non-specific organic acids. The CHA/CFA ratio in all cases were lesser than 1,0 and in more that 50 % of cases it was lesser than 0,5. The investigations conducted shows that the stocks of humus in soil of Antarctica are not estimated and till now we

Space weather effects on lower ionosphere: First investigation from Bharati station during 34th Indian scientific expedition to Antarctica

NASA Astrophysics Data System (ADS)

Guha, Anirban; Saha, Kumarjit; De, Barin Kumar; Subrahmanyam, Kandula Venkata; Shreedevi, P. R.

2017-04-01

We investigate the solar flare effects on the D-region of the ionosphere with the help of VLF (Very Low Frequency) radio waves using a portable E-field system from Antarctica during the summer period of 34th Indian scientific expedition. Two GPS time synchronized VLF receivers, one located at Bharati, Antarctica (geographical latitude 69.40°S, longitude 76.18°E) and another located at Tripura, India (geographical latitude 23.84°N, longitude 91.28°E) were operated simultaneously to infer common mode changes in the lower ionosphere for a number of solar flares events. The two systems constantly monitored the carrier amplitude and phase of the MSK (Minimum Shift Keying) modulated navy transmitter located in Australia (Callsign: NWC, 19.8 kHz, geographical latitude 21.88°S, longitude 114.13°E), around 5.6 Mm great circle distance from the two receivers. The results are interpreted in terms of Earth-ionosphere wave-guide characteristics. A Long Wave Propagation Capability (LWPC) model study is also performed to infer the changes in the daytime electron density in polar D-region ionosphere during the solar flares. The exponential fit of the modeled electron density change with average X-ray flux change shows an excellent correlation (R2 value 0.95). The exponential fit is utilized to infer the daytime electron density change in the polar ionosphere during solar flare events. The analyses indicate that small solar flares of class 'C' can be very effectively detected with the portable antenna system even if the receiver is located in polar coastal region compared to equatorial region. The expedition results also demonstrate the feasibility of using portable VLF receivers from the coastal stations for monitoring the polar lower ionosphere from Antarctica and open up new opportunities for long term exploration.

Potential methane reservoirs beneath Antarctica.

PubMed

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.

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

Code of Federal Regulations, 2011 CFR

2011-10-01

... 45 Public Welfare 3 2011-10-01 2011-10-01 false Restrictions on collection of meteorites in 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...

New Crustal Boundary Revealed Beneath the Ross Ice Shelf, Antarctica, through ROSETTA-Ice Integrated Aerogeophysics, Geology, and Ocean Research

NASA Astrophysics Data System (ADS)

Tinto, K. J.; Siddoway, C. S.; Bell, R. E.; Lockett, A.; Wilner, J.

2017-12-01

Now submerged within marine plateaus and rises bordering Antarctica, Australia and Zealandia, the East Gondwana accretionary margin was a belt of terranes and stitched by magmatic arcs, later stretched into continental ribbons separated by narrow elongate rifts. This crustal architecture is known from marine geophysical exploration and ocean drilling of the mid-latitude coastal plateaus and rises. A concealed sector of the former East Gondwana margin that underlies the Ross Ice Shelf (RIS), Antarctica, is the focus of ROSETTA-ICE, a new airborne data acquisition campaign that explores the crustal makeup, tectonic boundaries and seafloor bathymetry beneath RIS. Gravimeters and a magnetometer are deployed by LC130 aircraft surveying along E-W lines spaced at 10 km, and N-S tie lines at 55 km, connect 1970s points (RIGGS) for controls on ocean depth and gravity. The ROSETTA-ICE survey, 2/3 completed thus far, provides magnetic anomalies, Werner depth-to-basement solutions, a new gravity-based bathymetric model at 20-km resolution, and a new crustal density map tied to the 1970s data. Surprisingly, the data reveal that the major lithospheric boundary separating East and West Antarctica lies 300 km east of the Transantarctic Mountains, beneath the floating RIS. The East and West regions have contrasting geophysical characteristics and bathymetry, with relatively dense lithosphere, low amplitude magnetic anomalies, and deep bathymetry on the East Antarctica side, and high amplitude magnetic anomalies, lower overall density and shallower water depths on the West Antarctic side. The Central High, a basement structure cored at DSDP Site 270 and seismically imaged in the Ross Sea, continues beneath RIS as a faulted but coherent crustal ribbon coincident with the tectonic boundary. The continuity of Gondwana margin crustal architecture discovered beneath the West Antarctic Ice Sheet requires a revision of the existing tectonic framework. The sub-RIS narrow rift basins and

Distribution of calcretes and gypcretes in southwestern United States and their uranium favorability, based on a study of deposits in Western Australia and South West Africa (Namibia)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Carlisle, D.; Merifield, P.M.; Orme, A.R.

Calcrete, dolocrete, and gypcrete carnotite are abundant in western Australia and Namib Desert, although only a few are of ore grade. The geology of these deposits are described. A genetic classification of calcretes emphasizing uranium favorability was developed, based on the distinction between pedogenic and nonpedogenic processes. Similarities between western Australia and South West Africa give support for the conclusions that lateral transport of U in groundwater is essential to ore deposition and that bedrock barriers or constrictions which narrow the channel of subsurface flow or force the water close to the land surface, greatly favor the formation of uraniferousmore » calcretes. Criteria for uranium favorability deduced from the Australian and South West African studies were applied in a preliminary way to the southern Basin and Range Province of U.S. The procedure is to search for areas in which nonpedogenic calcrete or gypcrete may have developed. A caliche distribution map was compiled from soil survey and field data. Many areas were visited and some of the more interesting are described briefly, including parts of Clark County, Nevada, with occurrences of carnotite in calcrete. (DLC)« less

Can increasing CO2 cool Antarctica?

NASA Astrophysics Data System (ADS)

Schmithuesen, Holger; Notholt, Justus; König-Langlo, Gert; Lemke, Peter

2014-05-01

CO2 is the strongest anthropogenic forcing agent for climate change since pre-industrial times. Like other greenhouse gases, CO2 absorbs terrestrial surface radiation and causes emission from the atmosphere to space. As the surface is generally warmer than the atmosphere, the total long-wave emission to space is commonly less than the surface emission. However, this does not hold true for the high elevated areas of central Antarctica. Our investigations show, that for the high elevated areas of Antarctica the greenhouse effect (GHE) of CO2 is commonly around zero or even negative. This is based on the quantification of GHE as the difference between long-wave surface emission and top of atmosphere emission. We demonstrate this behaviour with the help of three models: a simple two-layer model, line-by-line calculations, and an ECMWF experiment. Additionally, in this region an increase in CO2 concentration leads to an instantaneous increased long-wave energy loss to space, which is a cooling effect on the earth-atmosphere system. However, short-wave warming by the weak absorption of solar radiation by CO2 are not taken into account here. The reason for this counter-intuitive behaviour is the fact that in the interior of Antarctica the surface is often colder than the stratosphere above. Radiation from the surface in the atmospheric window emitted to space is then relatively lower compared to radiation in the main CO2 band around 15 microns, which originates mostly from the stratosphere. Increasing CO2 concentration leads to increasing emission from the atmosphere to space, while blocking additional portions of surface emission. If the surface is colder than the stratosphere, this leads to additional long-wave energy loss to space for increasing CO2. Our findings for central Antarctica are in strong contrast to the generally known effect that increasing CO2 has on the long-wave emission to space, and hence on the Antarctic climate.

The Landsat Image Mosaic of Antarctica

NASA Astrophysics Data System (ADS)

Bindschadler, R.; Vornberger, P.; Fleming, A.; Fox, A.; Morin, P.

2008-12-01

The first-ever true-color, high-resolution digital mosaic of Antarctica has been produced from nearly 1100 Landsat-7 ETM+ images collected between 1999 and 2003. The Landsat Image Mosaic of Antarctica (LIMA) project was an early benchmark data set of the International Polar Year and represents a close and successful collaboration between NASA, USGS, the British Antarctic Survey and the National Science Foundation. The mosaic was successfully merged with lower resolution MODIS data south of Landsat coverage to produce a complete true-color data set of the entire continent. LIMA is being used as a platform for a variety of education and outreach activities. Central to this effort is the NASA website 'Faces of Antarctica' that offers the web visitor the opportunity to explore the data set and to learn how these data are used to support scientific research. Content is delivered through a set of mysteries designed to pique the user's interest and to motivate them to delve deeper into the website where there are various videos and scientific articles for downloading. Detailed lesson plans written by teachers are provided for classroom use and Java applets let the user track the motion of ice in sequential Landsat images. Web links take the user to other sites where they can roam over the imagery using standard pan and zoom functions, or search for any named feature in the Antarctic Geographic Names data base that returns to the user a centered true-color view of any named feature. LIMA also has appeared is a host of external presentations from museum exhibits, to postcards and large posters. It has attracted various value-added providers that increase LIMA's accessibility by allowing users to specify subsets of the very large data set for individual downloads. The ultimate goal of LIMA in the public and educational sector is to enable everyone to become more familiar with Antarctica.

33 CFR 151.79 - Operating requirements: Discharge of sewage within Antarctica.

Code of Federal Regulations, 2014 CFR

2014-07-01

... of sewage within Antarctica. 151.79 Section 151.79 Navigation and Navigable Waters COAST GUARD... Pollution and Sewage § 151.79 Operating requirements: Discharge of sewage within Antarctica. (a) A vessel... miles of Antarctic land or ice shelves; beyond such distance, sewage stored in a holding tank must not...

33 CFR 151.79 - Operating requirements: Discharge of sewage within Antarctica.

Code of Federal Regulations, 2010 CFR

2010-07-01

... of sewage within Antarctica. 151.79 Section 151.79 Navigation and Navigable Waters COAST GUARD... Pollution and Sewage § 151.79 Operating requirements: Discharge of sewage within Antarctica. (a) A vessel... miles of Antarctic land or ice shelves; beyond such distance, sewage stored in a holding tank must not...

33 CFR 151.79 - Operating requirements: Discharge of sewage within Antarctica.

Code of Federal Regulations, 2013 CFR

2013-07-01

... of sewage within Antarctica. 151.79 Section 151.79 Navigation and Navigable Waters COAST GUARD... Pollution and Sewage § 151.79 Operating requirements: Discharge of sewage within Antarctica. (a) A vessel... miles of Antarctic land or ice shelves; beyond such distance, sewage stored in a holding tank must not...

33 CFR 151.79 - Operating requirements: Discharge of sewage within Antarctica.

Code of Federal Regulations, 2012 CFR

2012-07-01

... of sewage within Antarctica. 151.79 Section 151.79 Navigation and Navigable Waters COAST GUARD... Pollution and Sewage § 151.79 Operating requirements: Discharge of sewage within Antarctica. (a) A vessel... miles of Antarctic land or ice shelves; beyond such distance, sewage stored in a holding tank must not...

33 CFR 151.79 - Operating requirements: Discharge of sewage within Antarctica.

Code of Federal Regulations, 2011 CFR

2011-07-01

... of sewage within Antarctica. 151.79 Section 151.79 Navigation and Navigable Waters COAST GUARD... Pollution and Sewage § 151.79 Operating requirements: Discharge of sewage within Antarctica. (a) A vessel... miles of Antarctic land or ice shelves; beyond such distance, sewage stored in a holding tank must not...

The Triassic dicynodont Kombuisia (Synapsida, Anomodontia) from Antarctica, a refuge from the terrestrial Permian-Triassic mass extinction.

PubMed

Fröbisch, Jörg; Angielczyk, Kenneth D; Sidor, Christian A

2010-02-01

Fossils from the central Transantarctic Mountains in Antarctica are referred to a new species of the Triassic genus Kombuisia, one of four dicynodont lineages known to survive the end-Permian mass extinction. The specimens show a unique combination of characters only present in this genus, but the new species can be distinguished from the type species of the genus, Kombuisia frerensis, by the presence of a reduced but slit-like pineal foramen and the lack of contact between the postorbitals. Although incomplete, the Antarctic specimens are significant because Kombuisia was previously known only from the South African Karoo Basin and the new specimens extend the taxon's biogeographic range to a wider portion of southern Pangaea. In addition, the new finds extend the known stratigraphic range of Kombuisia from the Middle Triassic subzone B of the Cynognathus Assemblage Zone into rocks that are equivalent in age to the Lower Triassic Lystrosaurus Assemblage Zone, shortening the proposed ghost lineage of this taxon. Most importantly, the occurrence of Kombuisia and Lystrosaurus mccaigi in the Lower Triassic of Antarctica suggests that this area served as a refuge from some of the effects of the end-Permian extinction. The composition of the lower Fremouw Formation fauna implies a community structure similar to that of the ecologically anomalous Lystrosaurus Assemblage Zone of South Africa, providing additional evidence for widespread ecological disturbance in the extinction's aftermath.

Finger blood flow in Antarctica

PubMed Central

Elkington, E. J.

1968-01-01

1. Finger blood flow was estimated, by strain-gauge plethysmography, before and during a 1 hr immersion in ice water, on twenty-five men throughout a year at Wilkes, Antarctica. A total of 121 satisfactory immersions were made. 2. Blood flow before and during immersion decreased significantly in the colder months of the year, and the increase caused by cold-induced vasodilatation (CIVD) became less as the year progressed. The time of onset, blood flow at onset, and frequency of the cycles of CIVD showed no significant relation to the coldness of the weather (as measured by mean monthly wind chill) or the time in months. Comparisons of blood flow before and after five field trips (average duration 42 days), on which cold exposure was more severe than at Wilkes station, gave similar results. 3. The results suggest that vasoconstrictor tone increased. This interpretation agrees with previous work on general acclimatization in Antarctica, but contrasts with work elsewhere on local acclimatization of the hands. PMID:5684034

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

ERIC Educational Resources Information Center

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…

Development of the Circum-Antarctic Current

USGS Publications Warehouse

Kennett, J.P.; Houtz, R.E.; Andrews, P.B.; Edwards, A.R.; Gostin, V.A.; Hajos, M.; Hampton, M.A.; Jenkins, D.G.; Margolis, S.V.; Ovenshine, A.T.; Perch-Nielsen, K.

1974-01-01

Deep-sea drilling in the Southern Ocean south of Australia and New Zealand shows that the Circum-Antarctic Current developed about 30 million years ago in the middle to late Oligocene when final separation occurred between Antarctica and the continental Soulth Tasman Rise. Australia had commenced drifting northward from Antarctica 20 million years before this.

Sedimentation patterns in the Barberton Mountain Land, South Africa, and the Pilbara Block, Australia: Evidence for Archean rifted continental margins

NASA Astrophysics Data System (ADS)

Eriksson, Kenneth A.

1982-01-01

Archean supracrustal sequences in the Barberton Mountain Land, South Africa, and the Pilbara Block, Australia, consist of lower volcanic and upper dominantly terrigenous clastic intervals. As evidenced by the paleoenvironments of intercalated sedimentary horizons, volcanism occurred mainly in shallow waters. The overlying ca 3.3 Ga sedimentary intervals contain various common as well as unique paleoenvironments, the understanding of which places significant constraints on Archean crustal models. Lateral and vertical associations of inferred paleoenvironments are used to interpret the geotectonic history of the Archean depositories. The early sedimentary history of the greenstone belts is characterized by terrestrial and subaqueous graben-fill associations of facies related to the initial rift stage of basin development. Continued rifting and initial spreading produced submarine grabens within which ironformations accumulated in response to waning volcanism. Source area uplift resulted in progradation of submarine fans across the basinal chemical sediments. The turbidites are gradational directly into braided alluvial sediments, in part of fan delta origin, suggesting that the continental to marine transition occurred along a narrow continental shelf. In the Barberton Mountain Land the steep-rift margin was succeeded by the development of a stable continental shelf or shelf rise margin through progradation of the turbidite wedge possibly in association with a eustatic rise in sea-level related to continued spreading. On this shelf extensive tidal, deltaic and barrier beach sediments accumulated. Sedimentation was terminated by closure of the passive margin oceans. The late-Archean Pongola Supergroup in South Africa is considered to be the late-orogenic molasse response to this closure and represents the completion of the Wilson cycle.

Results and Error Estimates from GRACE Forward Modeling over Antarctica

NASA Astrophysics Data System (ADS)

Bonin, Jennifer; Chambers, Don

2013-04-01

Forward modeling using a weighted least squares technique allows GRACE information to be projected onto a pre-determined collection of local basins. This decreases the impact of spatial leakage, allowing estimates of mass change to be better localized. The technique is especially valuable where models of current-day mass change are poor, such as over Antarctica. However when tested previously, the least squares technique has required constraints in the form of added process noise in order to be reliable. Poor choice of local basin layout has also adversely affected results, as has the choice of spatial smoothing used with GRACE. To develop design parameters which will result in correct high-resolution mass detection and to estimate the systematic errors of the method over Antarctica, we use a "truth" simulation of the Antarctic signal. We apply the optimal parameters found from the simulation to RL05 GRACE data across Antarctica and the surrounding ocean. We particularly focus on separating the Antarctic peninsula's mass signal from that of the rest of western Antarctica. Additionally, we characterize how well the technique works for removing land leakage signal from the nearby ocean, particularly that near the Drake Passage.

Survival and Recovery of Phaeocystis Antarctica (Prymnesiophyceae) from Prolonged Darkness and Freezing

EPA Science Inventory

The colony-forming haptophyte Phaeocystis antarctica is an important primary producer in the Ross Sea, and must survive long periods of darkness and freezing in this extreme environment. We conducted experiments on the responses of P. antarctica-dominated phytoplankton assemblage...

Antarctica--the Ultimate Summer Institute.

ERIC Educational Resources Information Center

Van Wey, Nate J.

1995-01-01

Describes personal experiences of a participant in the National Science Foundation program, Teachers Experiencing Antarctica. Uses the study of the temperature history of Taylor Dome to provide teachers with the experience of research and help other teachers recognize that there are opportunities outside the classroom for personal and professional…

Gondwanaland from 650-500 Ma assembly through 320 Ma merger in Pangea to 185-100 Ma breakup: supercontinental tectonics via stratigraphy and radiometric dating

NASA Astrophysics Data System (ADS)

Veevers, J. J.

2004-12-01

Gondwanaland lasted from the 650-500 Ma (late Neoproterozoic-Cambrian) amalgamation of African and South American terranes to Antarctica-Australia-India through 320 Ma (mid-Carboniferous) merging with Laurussia in Pangea to breakup from 185 to 100 Ma (Jurassic and Early Cretaceous). Gondwanaland straddled the equator at 540 Ma, lay wholly in the Southern Hemisphere by 350 Ma, and then rotated clockwise so that at 250 Ma Australia reached the S pole and Africa the equator. By initial breakup of Pangea at 185 Ma, Gondwanaland had moved northward such that North Africa reached 35°N. The first clear picture of Gondwanaland, in the Cambrian, shows the assembly of continents with later Laurentian, European and Asian terranes along the "northern" margin, and with a trench along the "western" and "southern" margins, reflected by a 10,000-km-long chain of 530-500 Ma granites. The interior was crossed by the Prydz-Leeuwin and Mozambique Orogenic Belts. The shoreline lapped the flanks of uplifts generated during this complex terminal Pan-Gondwanaland (650-500 Ma) deformation, which endowed Gondwanaland with a thick, buoyant crust and lithosphere and a nonmarine siliciclastic facies. During the Ordovician, terranes drifted from Africa as the first of many transfers of material to the "northern" continents. Central Australia was crossed by the sea, and the eastern margin and ocean floor were flooded by grains of quartz (and 600-500 Ma zircon) from Antarctica. Ice centres in North Africa and southern South America/Africa waxed and waned in the latest Ordovician, Early Silurian, latest Devonian, and Early Carboniferous. In the mid-Carboniferous, Laurussia and Gondwanaland merged in the composite called Pangea by definitive right-lateral contact along the Variscan suture, with collisional stress and subsequent uplift felt as far afield as Australia. Ice sheets developed on the tectonic uplands of Gondwanaland south of 30°S. In the Early Permian, the self-induced heat beneath

A web service framework for astronomical remote observation in Antarctica by using satellite link

NASA Astrophysics Data System (ADS)

Jia, M.-h.; Chen, Y.-q.; Zhang, G.-y.; Jiang, P.; Zhang, H.; Wang, J.

2018-07-01

Many telescopes are deployed in Antarctica as it offers excellent astronomical observation conditions. However, because Antarctica's environment is harsh to humans, remote operation of telescope is necessary for observation. Furthermore, communication to devices in Antarctica through satellite link with low bandwidth and high latency limits the effectiveness of remote observation. This paper introduces a web service framework for remote astronomical observation in Antarctica. The framework is based on Python Tornado. RTS2-HTTPD and REDIS are used as the access interface to the telescope control system in Antarctica. The web service provides real-time updates through WebSocket. To improve user experience and control effectiveness under the poor satellite link condition, an agent server is deployed in the mainland to synchronize the Antarctic server's data and send it to domestic users in China. The agent server will forward the request of domestic users to the Antarctic master server. The web service was deployed and tested on Bright Star Survey Telescope (BSST) in Antarctica. Results show that the service meets the demands of real-time, multiuser remote observation and domestic users have a better experience of remote operation.

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

Code of Federal Regulations, 2012 CFR

2012-10-01

... 45 Public Welfare 3 2012-10-01 2012-10-01 false Restrictions on collection of meteorites in 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...

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

Code of Federal Regulations, 2014 CFR

2014-10-01

... 45 Public Welfare 3 2014-10-01 2014-10-01 false Restrictions on collection of meteorites in 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...

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

Code of Federal Regulations, 2013 CFR

2013-10-01

... 45 Public Welfare 3 2013-10-01 2013-10-01 false Restrictions on collection of meteorites in 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...

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

PubMed

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

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

PubMed Central

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

It’s good to be big--- Phaeocystis antarctica colony size under the influence of zooplankton grazers

EPA Science Inventory

The haptophyte Phaeocystis antarctica forms extremely dense accumulations in the Ross Sea, Antarctica, and accounts for over 60% of the seasonal primary production. Similar to the Phaeocystis species in the northern hemisphere, P. antarctica exists as solitary cells and mucilagin...

IT’S GOOD TO BE BIG—PHAEOCYSTIS ANTARCTICA COLONY SIZE UNDER THE INFLUENCE OF ZOOPLANKTON GRAZERS

EPA Science Inventory

The haptophyte Phaeocystis antarctica forms extremely dense accumulations in the Ross Sea, Antarctica, and accounts for over 60% of the seasonal primary production. Similar to the Phaeocystis species in the northern hemisphere, P. antarctica exists as solitary cells and mucilagin...

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

Treesearch

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...

Declassified Intelligence Satellite Photography (DISP) Coverage of Antarctica

NASA Technical Reports Server (NTRS)

Bindschadler, Robert; Seider, Wendy

1998-01-01

This report summarizes the results of a nine-week summer project examining all Declassified Intelligence Satellite Photography (DISP) of Antarctica. It was discovered that the data were collected in three separate missions during 1962 and 1963. The first two missions covered only the coastal areas, while the third mission covered the entire continent. Many of the 1782 frames collected were cloudy. This is especially true of West Antarctica. An optimal set of photographs covering the entire Antarctic coastline is identified along with some examples that show changes in the coastline which have occurred since the early 1960s.

Novel Avulaviruses in Penguins, Antarctica.

PubMed

Neira, Víctor; Tapia, Rodrigo; Verdugo, Claudio; Barriga, Gonzalo; Mor, Sunil; Ng, Terry Fei Fan; García, Victoria; Del Río, José; Rodrigues, Pedro; Briceño, Cristóbal; Medina, Rafael A; González-Acuña, Daniel

2017-07-01

We identified 3 novel and distinct avulaviruses from Gentoo penguins sampled in Antarctica. We isolated these viruses and sequenced their complete genomes; serologic assays demonstrated that the viruses do not have cross-reactivity between them. Our findings suggest that these 3 new viruses represent members of 3 novel avulavirus species.

Organic carbon stocks in permafrost-affected soils from Admiralty Bay, Antarctica

USGS Publications Warehouse

Simas, F.N.B.; Schaefer, C.E.G.R.; Mendonça, E.S.; Silva, I.R.; Santana, R.M.; Ribeiro, A.S.S.

2007-01-01

Recent works show that organic matter accumulation in some soils from coastal Antarctica is higher than previously expected. The objective of the present work was to estimate the organic C stocks for soils from maritime Antarctica. Cryosols from subpolar desert landscapes presented the lowest organic C stocks. Ornithogenic soils are the most important C reservoirs in terrestrial ecosystems in this part of Antarctica. Although these soils correspond to only 2.5 % of the ice-free areas at Admiralty Bay, they contain approximately 20 % of the estimated C stock. Most of the organic C in the studied soils is stored in the active layer but in some cases the C is also stored in the permafrost.

Antarctica: As seismic as other plates

NASA Astrophysics Data System (ADS)

Richman, Barbara T.

Antarctica shakes, rattles, and rolls just as much as other slow-moving plates. Emile Okal, a Yale University seismologist, told colleagues at the AGU Fall Meeting that although the Antarctic plate is not moving across the earth as fast as other continents, it has a seismicity similar to other plates. His findings refute the claim that a ring of spreading ridges that surrounds the plate leaves Antarctica stress free.The small number of reports of plate seismicity, Okal explained, has been used to argue that the ridges that surround the plate are unable to transmit tectonic stresses and would make the Antarctic plate motionless and free of seismic stress. However, when Okal added up the total seismic energy released during the last 55 years, he found it similar to that of the African plate, which is comparable in size.

Where does CO2 in Antarctica cool the atmosphere ?

NASA Astrophysics Data System (ADS)

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.

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

NASA Technical Reports Server (NTRS)

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 (< or = 200 sq km) with reduced surface accumulation. Estimates of Antarctic surface mass balance rely on sparse point measurements or coarse atmospheric models that do not capture these local processes, and overestimate the net mass input in wind-scour zones. Here we combine airborne radar observations of unconformable stratigraphic layers with lidar-derived surface roughness measurements to identify extensive wind-scour zones over Dome A, in the interior of East 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.

Crust and Upper Mantle Structure of Antarctica from Rayleigh Wave Tomography

NASA Astrophysics Data System (ADS)

Wiens, D. A.; Heeszel, D. S.; Sun, X.; Chaput, J. A.; Aster, R. C.; Nyblade, A.; Anandakrishnan, S.; Wilson, T. J.; Huerta, A. D.

2012-12-01

We combine data from three temporary arrays of seismometers (AGAP/GAMSEIS 2007-2010, ANET/POLENET 2007-2012, TAMSEIS 2001-2003) deployed across Antarctica, along with permanent stations in the region, to produce a large scale shear velocity model of the continent extending from the Gamburtsev Subglacial Mountains (GSM) in East Antarctica, across the Transantarctic Mountains (TAM) and West Antarctic Rift System (WARS) to Marie Byrd Land (MBL) in West Antarctica. Our combined dataset consists of Rayleigh wave phase and amplitude measurements from 112 stations across the study region. We first invert for 2-D Rayleigh wave phase velocities using the two-plane wave method. These results are then inverted for shear velocity structure using crustal thicknesses derived from ambient noise tomography and teleseismic receiver functions. We refine our shear velocity model by performing a Monte Carlo simulation that explores the tradeoff between crustal thickness and upper mantle seismic velocities. The resulting model is higher resolution than previous studies (~150 km resolution length) and highlights significant differences in crustal and uppermost mantle structure between East and West Antarctica in greater detail than previously possible. East Antarctica is underlain by thick crust (reaching ~55 km beneath the GSM) and fast, cratonic lithosphere. West Antarctica is defined by thinner crust and slow upper mantle velocities indicative of its more recent tectonic activity. The observed boundary in crustal thickness closely follows the TAM front. MBL is underlain by a thicker lithosphere than that observed beneath the WARS, but slow mantle velocities persist to depths greater than 200 km, indicating a 'deep seated' (i.e. deeper than the deepest resolvable features of our model) thermal source for volcanism in the region. The slowest seismic velocities at shallow depths are observed in the Terror Rift region of the Ross Sea along an arc following the TAM front, where the most

All-year-round aerosol chemical composition at Dome C, Antarctica

NASA Astrophysics Data System (ADS)

Udisti, Roberto; Becagli, Silvia; Frosini, Daniele; Galli, Gaia; Ghedini, Costanza; Rugi, Francesco; Severi, Mirko; Traversi, Rita

2010-05-01

induced) controlling the MSA-H2SO4 ratio from DMS. Since, in summer, DMS in route toward central Antarctica is subjected to larger atmospheric concentrations of OH (and/or BrO) radical, lower temperatures and lower humidity, all conditions promoting the preferential H2SO4 formation, non-sea-salt sulphate is assumed to be the most reliable biogenic marker at Dome C. A further insight from ice-core stratigraphies is concerning the sea salt sodium (ssNa) content in snow precipitation as a reliable marker of sea-ice extent, via frost-flower formation at the pack-ice seasonal growth. This interpretation faces with the classical view that consider higher sea-spray production as caused by an increase in zonal wind intensity. Sea spray originated from frost flowers can be distinguished from sea spray coming from bulk sea-water by the lower sulphate/sodium ratio (caused by mirabilite - Na2SO4 10H20 - precipitation occurring when sea-ice temperature falls below -8°C). High resolution aerosol measurement can allow to identify different sea-spray sources and quantify frost flowers contribution to the annual ssNa budget. Finally, dust recorded in ice cores can be used as a valuable proxy for changes in hydrological cycles in the dust source areas and transport processes (pathways and scavenging). The geochemical characterization of dust in the present-day aerosol, compared with chemical composition of soils collected in South America and Australia, allows identifying the major dust source area (South America) and reconstructing pathways of atmospheric circulation. South America role in feeding dust aerosol at Dome C was supported also by comparing aerosol composition with satellite observations (dust plumes on the source sites) and back-trajectory analysis (air masses reaching Antarctica) during massive dust-storm events.

Crustal heat production and estimate of terrestrial heat flow in central East Antarctica, with implications for thermal input to the East Antarctic ice sheet

NASA Astrophysics Data System (ADS)

Goodge, John W.

2018-02-01

East Antarctica resembles that in the Proterozoic Arunta and Tennant Creek inliers of Australia but is dissimilar to other areas like the Central Australian Heat Flow Province that are characterized by anomalously high heat flow. Age variation within the sample suite indicates that central East Antarctic lithosphere is heterogeneous, yet the average heat production and heat flow of four age subgroups cluster around the group mean, indicating minor variation in the thermal contribution to the overlying ice sheet from upper crustal heat production. Despite these minor differences, ice-sheet models may favor a geologically realistic input of crustal heat flow represented by the distribution of ages and geothermal characteristics found in these glacial clasts.

Landscape evolution of Antarctica

USGS Publications Warehouse

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

2007-01-01

shelf before retreating to its present dimensions at ~13.5 Ma. Subsequent changes in ice extent have been forced mainly by sea-level change. Weathering rates of exposed bedrock have been remarkably slow at high elevations around the margin of East Antarctica under the hyperarid polar climate of the last ~13.5 Ma, offering potential for a long quantitative record of ice-sheet evolution with techniques such as cosmogenic isotope analysis

Origins of native vascular plants of Antarctica: comments from a historical phytogeography viewpoint.

PubMed

Mosyakin, S L; Bezusko, L G; Mosyakin, A S

2007-01-01

The article provides an overview of the problem of origin of the only native vascular plants of Antarctica, Deschampsia antartica (Poaceae) and Colobanthus quitensis (Caryophyllaceae), from the viewpoint of modern historical phytogeography and related fields of science. Some authors suggested the Tertiary relict status of these plants in Antarctica, while others favour their recent Holocene immigration. Direct data (fossil or molecular genetic ones) for solving this controversy is still lacking. However, there is no convincing evidence supporting the Tertiary relict status of these plants in Antarctica. Most probably D. antarctica and C. quitensis migrated to Antarctica in the Holocene or Late Pleistocene (last interglacial?) through bird-aided long-distance dispersal. It should be critically tested by (1) appropriate methods of molecular phylogeography, (2) molecular clock methods, if feasible, (3) direct paleobotanical studies, (4) paleoclimatic reconstructions, and (5) comparison with cases of taxa with similar distribution/dispersal patterns. The problem of the origin of Antarctic vascular plants is a perfect model for integration of modern methods of molecular phylogeography and phylogenetics, population biology, paleobiology and paleogeography for solving a long-standing enigma of historical plant geography and evolution.

Dynamic spatiotemporal trends of imported dengue fever in Australia

PubMed Central

Huang, Xiaodong; Yakob, Laith; Devine, Gregor; Frentiu, Francesca D.; Fu, Shiu-Yun; Hu, Wenbiao

2016-01-01

Dengue fever (DF) epidemics in Australia are caused by infected international travellers and confined to Northern Queensland where competent vectors exist. Recent analyses suggest that global trade and climate change could lead to the re-establishment of Ae. aegypti across the country and promote the spread of dengue nationally. This study aimed to describe the dynamic spatiotemporal trends of imported DF cases and their origins, identify the current and potential future high-risk regions and locate areas that might be at particular risk of dengue transmission should competent mosquito vectors expand their range. Our results showed that the geographical distribution of imported DF cases has significantly expanded in mainland Australia over the past decade. In recent years, the geographical distribution of source countries of DF has expanded from the Pacific region and Asia to include Africa and the Americas. Australia is now exposed to dengue importations from all of the regions involved in the current global pandemic. The public health implications of a range expansion of dengue mosquito vectors are severe. Enhanced mosquito surveillance in those areas that have high imported cases is called for to reduce emerging threats from this globally expanding pathogen. PMID:27460696

NASA Scientific Balloon in Antarctica

NASA Image and Video Library

2017-12-08

NASA image captured December 25, 2011 A NASA scientific balloon awaits launch in McMurdo, Antarctica. The balloon, carrying Indiana University's Cosmic Ray Electron Synchrotron Telescope (CREST), was launched on December 25. After a circum-navigational flight around the South Pole, the payload landed on January 5. The CREST payload is one of two scheduled as part of this seasons' annual NASA Antarctic balloon Campaign which is conducted in cooperation with the National Science Foundation's Office of Polar Programs. The campaign's second payload is the University of Arizona's Stratospheric Terahertz Observatory (STO). You can follow the flights at the Columbia Scientific Balloon Facility's web site at www.csbf.nasa.gov/antarctica/ice.htm Credit: NASA NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

Sleep and circadian rhythms in long duration space flight - Antarctica as an analogue environment

NASA Technical Reports Server (NTRS)

Gander, Philippa H.

1992-01-01

The feasibility of using Antarctica as an environment for studying the impact of unusual 24 h environmental cycles (zeitgebers) on the circadian system is discussed. Adaptation of circadian rhythms and sleep of three scientists travelling from New Zealand to Antarctica during summer (which is analogous to arrival at a lunar base during the lunar day) has been studied. Data obtained indicate that sleep occurred at the same clock time, but sleep quality was poorer in Antarctica, which can be explained by the fact that the circadian system delayed by about 2 h in Antarctica, as would be expected in a weaker zeitgeber environment. It is suggested that sleep could be improved by altering patterns of exposure to the available zeitgebers to increase their effective strength.

Southwest U. S. -East Antarctic (SWEAT) connection: A hypothesis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Moores, E.M.

A hypothesis for a late Precambrian fit of western North America with the Australia-Antarctic shield region permits the extension of many features through Antarctica and into other parts of Gondwana. Specifically, the Grenville orogen may extend around the coast of East Antarctica into India and Australia. The Wopmay orogen of northwest Canada may extend through eastern Australia into Antarctica and thence beneath the ice to connect with the Yavapai-Mazatzal orogens of the southwestern US. The ophiolitic belt of the latter may extend into East Antarctica. Counterparts of the Precambrian-Paleozoic sedimentary rocks along the US Cordilleran miogeocline may be present inmore » the Transantarctic Mountains. Orogenic belt boundaries provide useful piercing points for Precambrian continental reconstructions. The model implies that Gondwana and Laurentia rifted away from each other on one margin and collided some 300 m.y. later on their opposite margins to from the Appalachians.« less

Remote Triggering of Microseismicity in Antarctica

NASA Astrophysics Data System (ADS)

Ji, M.; Li, C.; Peng, Z.; Walter, J. I.

2017-12-01

It is well known that large distant earthquakes can trigger microearthquakes/tectonic tremors during or immediately following their surface waves. Globally, triggered seismicity is mostly found in active plate boundary regions. Recent studies have shown that icequakes in Antartica can also be triggered by teleseismic events. However, it is still not clear how widespread this phenomenon is and whether there are any connections between large earthquakes and subsequent glacial movements. In this study, we conduct a systematic search for remotely triggered activity in Antarctica following recent large earthquakes, including the 2004 Mw9.1 Sumatra, 2011 Mw9.1 Tohoku, 2012 Mw8.6 Indian Ocean and 2014-2015 Chile earthquakes. We download seismic data recorded at the POLENET (YT) and the Argentina Antarctica Network (AI) from the Incorporated Research Institutions for Seismology (IRIS) Data Management Center (DMC). We apply a 2-8 Hz band-pass-filter to the continuous waveforms and visually identify local events during and immediately after the large amplitude surface waves. Spectrograms are computed as additional tools to identify triggered seismicity and are further confirmed by comparing the signals before and after the distant mainshocks. So far we have identified possible triggered seismicity in both networks' area following the 2010 Chile and 2011 Tohoku earthquakes. Our next step is to apply a waveform matching method to automatically detect possible triggered seismicity and check through all the available networks in Antarctica for the last decades, which should help to better understand the potential interaction between large earthquakes and icequakes in this region.

Read--and Walk--to Antarctica

ERIC Educational Resources Information Center

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…

Accelerated thermokarst formation in the McMurdo Dry Valleys, Antarctica.

PubMed

Levy, Joseph S; Fountain, Andrew G; Dickson, James L; Head, James W; Okal, Marianne; Marchant, David R; Watters, Jaclyn

2013-01-01

Thermokarst is a land surface lowered and disrupted by melting ground ice. Thermokarst is a major driver of landscape change in the Arctic, but has been considered to be a minor process in Antarctica. Here, we use ground-based and airborne LiDAR coupled with timelapse imaging and meteorological data to show that 1) thermokarst formation has accelerated in Garwood Valley, Antarctica; 2) the rate of thermokarst erosion is presently ~ 10 times the average Holocene rate; and 3) the increased rate of thermokarst formation is driven most strongly by increasing insolation and sediment/albedo feedbacks. This suggests that sediment enhancement of insolation-driven melting may act similarly to expected increases in Antarctic air temperature (presently occurring along the Antarctic Peninsula), and may serve as a leading indicator of imminent landscape change in Antarctica that will generate thermokarst landforms similar to those in Arctic periglacial terrains.

Accelerated thermokarst formation in the McMurdo Dry Valleys, Antarctica

PubMed Central

Levy, Joseph S.; Fountain, Andrew G.; Dickson, James L.; Head, James W.; Okal, Marianne; Marchant, David R.; Watters, Jaclyn

2013-01-01

Thermokarst is a land surface lowered and disrupted by melting ground ice. Thermokarst is a major driver of landscape change in the Arctic, but has been considered to be a minor process in Antarctica. Here, we use ground-based and airborne LiDAR coupled with timelapse imaging and meteorological data to show that 1) thermokarst formation has accelerated in Garwood Valley, Antarctica; 2) the rate of thermokarst erosion is presently ~ 10 times the average Holocene rate; and 3) the increased rate of thermokarst formation is driven most strongly by increasing insolation and sediment/albedo feedbacks. This suggests that sediment enhancement of insolation-driven melting may act similarly to expected increases in Antarctic air temperature (presently occurring along the Antarctic Peninsula), and may serve as a leading indicator of imminent landscape change in Antarctica that will generate thermokarst landforms similar to those in Arctic periglacial terrains. PMID:23881292

Tufted hairgrass (Deschampsia caespitosa) exhibits a lower photosynthetic plasticity than Antarctic hairgrass (D. antarctica).

PubMed

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.

A Sled-Mounted Vibroseis Seismic Source for Geological Studies in Antarctica

NASA Astrophysics Data System (ADS)

Speece, M. A.; Luyendyk, B. P.; Harwood, D. M.; Powell, R. D.; Wilson, D. S.; Pekar, S. F.; Tulaczyk, S. M.; Rack, F. R.

2013-12-01

Given the success of recent vibrator seismic source (vibroseis) tests in Antarctica, we propose the purchase of a large vibroseis for dedicated use by United States Antarctic Program (USAP) projects in Antarctica. Long seismic reflection profiles across Antarctica can be accomplished efficiently by pulling a sled-mounted vibrator that in turn pulls a snow streamer of gimbaled geophones. A baseplate or pad in the center of the sled will be lowered to the ground and support most of the weight of the vibrator assembly while an actuator vibrates the ground at each source location. The vibroseis will be moved to remote locations using over-ice/snow traverses given the increased reliance on traversing for supplying remote sites in Antarctica. Total vibrator hold-down weight when fully assembled will be ~66,000 lbs. Other design features include a 475 HP Caterpillar C15 diesel engine for the hydraulic power unit. The new vibrator will use an INOVA P-wave vibrator system: new Model PLS-362 actuator with up to 60,000 lbs of peak force and frequency limit of 5 Hz to 250Hz. Antarctic research objectives that could be impacted by the use of a vibrator include: (1) mapping of sub-ice stratigraphic sequences for drilling for paleoclimate information, e.g. the deep sedimentary basins of West Antarctica (Ross and Ronne-Filchner Ice Shelves and related divides); (2) correlating offshore and onshore seismic data and complementing airborne geophysical surveys to help determine Antarctica's geologic history; (3) identifying ice-bedrock interface properties and exploring grounding-line processes for ice dynamics; (4) exploring subglacial lakes and water-routing systems; and, (5) investigating the physical properties of ice sheets. An Antarctic Vibroseis Advisory Committee (AVAC) will promote the use of the vibroseis capability among Antarctic geophysical, geological, glaciological and related scientists and groups by encouraging and facilitating the development and submission of

Mapping Antarctica using Landsat-8 - the preliminary results

NASA Astrophysics Data System (ADS)

Cheng, X.; Hui, F.; Qi, X.

2014-12-01

The first Landsat Image Mosaic of Antarctica (LIMA) was released in 2009, which was created by USGS, BAS, and NASA from more than 1,000 Landsat ETM+ scenes. As the first major scientific outcome of the IPY, LIMA supports current scientific polar research, encourages new projects, and helps the general public visualize Antarctica and changes happening to this southernmost environment. As the latest satellite of Landsat mission, the Landsat-8 images the entire Earth every 16 days in an 8-day offset from Landsat-7. Data collected by the instruments onboard the satellite are available to download at no charge within 24 hours of reception. The standard Landsat 8 products provided by the USGS EROS Center consist of quantized and calibrated scaled Digital Numbers (DN) in 16-bit unsigned integer format and can be rescaled to the Top Of Atmosphere (TOA) reflectance and/or radiance. With the support of USGS portal, we searched and downloaded more than 1600 scenes of Level 1 T- Terrain Corrected Landsat 8 image products covering Antarctica from late 2013 to early 2014. These data were converted to planetary radiance for further processing. Since the distribution of clouds in these images are random and much complicated, statistics on the distribution of clouds were performed and then help to decide masking those thicker cloud to keep more useful information left and avoid observation holes. A preliminary result of the Landsat-8 mosaic of Antarctica under the joint efforts of Beijing Normal University, NSIDC and University of Maryland will be released on this AGU fall meeting. Comparison between Landsat 7 and 8 mosaic products will also be done to find the difference or advantage of the two products.

The Landsat Image Mosaic of Antarctica

USGS Publications Warehouse

Bindschadler, Robert; Vornberger, P.; Fleming, A.; Fox, A.; Mullins, J.; Binnie, D.; Paulsen, S.J.; Granneman, Brian J.; 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.

Ice recrystallization inhibition proteins (IRIPs) and freeze tolerance in the cryophilic Antarctic hair grass Deschampsia antarctica E. Desv.

PubMed

John, Ulrik P; Polotnianka, Renatam M; Sivakumaran, Kailayapillai A; Chew, Orinda; Mackin, Leanne; Kuiper, Micheal J; Talbot, Jonathan P; Nugent, Gregory D; Mautord, Julie; Schrauf, Gustavo E; Spangenberg, German C

2009-04-01

Antarctic hair grass (Deschampsia antarctica E. Desv.), the only grass indigenous to Antarctica, has well-developed freezing tolerance, strongly induced by cold acclimation. Here, we show that in response to low temperatures, D. antarctica expresses potent recrystallization inhibition (RI) activity that, inhibits the growth of small ice crystals into potentially damaging large ones, is proteinaceous and localized to the apoplasm. A gene family from D. antarctica encoding putative homologs of an ice recrystallization inhibition protein (IRIP) has been isolated and characterized. IRIPs are apoplastically targeted proteins with two potential ice-binding motifs: 1-9 leucine-rich repeats (LRRs) and c. 16 'IRIP' repeats. IRIP genes appear to be confined to the grass subfamily Pooideae and their products, exhibit sequence similarity to phytosulphokine receptors and are predicted to adopt conformations with two ice-binding surfaces. D. antarctica IRIP (DaIRIP) transcript levels are greatly enhanced in leaf tissue following cold acclimation. Transgenic Arabidopsis thaliana expressing a DaIRIP has novel RI activity, and purified DaIRIP, when added back to extracts of leaves from non-acclimated D. antarctica, can reconstitute the activity found in acclimated plants. We propose that IRIP-mediated RI activity may contribute to the cryotolerance of D. antarctica, and thus to its unique ability to have colonized Antarctica.

A soil moisture index derived from thermal infrared sensor on-board geostationary satellites over Europe, Africa and Australia

NASA Astrophysics Data System (ADS)

Ghilain, Nicolas; Trigo, Isabel; Arboleda, Alirio; Barrios, Jose-Miguel; Batelaan, Okke; Gellens-Meulenberghs, Françoise

2017-04-01

Soil moisture plays a central role in the water cycle. In particular, it is a major component which variability controls the evapotranspiration process. Over the past years, there has been a large commitment of the remote sensing research community to develop satellites and retrieval algorithm for soil moisture monitoring over continents. Most of those rely on the observation in the microwave lengths, making use either of passive, active or both methods combined. However, the available derived products are given at a relatively low spatial resolution for applications at the kilometer scale over entire continents, and with a revisit time that may not be adequate for all applications, as for example agriculture. Thermal infrared observations from a combination of geostationary satellites offer a global view of continents every hour (or even at higher frequency) at a few kilometers resolution, which makes them attractive as another, and potentially complementary, source of information of surface soil moisture. In this study, the Copernicus LST and the LSA-SAF LST are used to derive soil moisture over entire continents (Europe, Africa, Australia). The derived soil moisture is validated against in-situ observations and compared to other available products from remote sensing (SMOS, ASCAT) and from numerical weather prediction (ECMWF). We will present the result of this validation, and will show how it could be used in continental scale evapotranspiration monitoring.

Suicide of first-generation immigrants in Australia, 1974-2006.

PubMed

Ide, Naoko; Kõlves, Kairi; Cassaniti, Maria; De Leo, Diego

2012-12-01

This study analysed suicide rates among first-generation immigrants in Australia from 1974 to 2006, and compared their suicide risks against the Australian-born population. It also examined the associations between the suicide rates of immigrants from 23 selected countries of birth during 2001-2006, and in their home countries. Age-standardised suicide rates (15+ years) and rate ratios, with a 95 % confidence interval, during 1974-2006 were calculated for country of birth (COB) groups. Spearman's rank correlation coefficient was calculated between COB-specific immigrant suicide rates during 2001-2006 in Australia and in their homelands. Suicide rates showed a decreasing time-trend among all COB groups for both genders in Australia. The lowest suicide rates were found during 2004-2006, compared to other year groups. Throughout the study period, males born in Eastern, Northern and Western Europe and New Zealand had the highest suicide rates in Australia. For females, the highest rates were among those born in Western Europe and the UK (including Ireland). Male and female migrants born in North Africa and the Middle East, Southern and Central Asia and South East Asia showed the lowest suicide rates. There was a significant correlation between male immigrant suicide rates by COB and the rates of their home countries. The patterns of suicide rates in immigrants were influenced by the social and cultural norms of their COB. The overall decrease in suicide risk among immigrants was particularly evident in males.

The crustal thickness of West Antarctica

NASA Astrophysics Data System (ADS)

Chaput, J.; Aster, R. C.; Huerta, A.; Sun, X.; Lloyd, A.; Wiens, D.; Nyblade, A.; Anandakrishnan, S.; Winberry, J. P.; Wilson, T.

2014-01-01

P-to-S receiver functions (PRFs) from the Polar Earth Observing Network (POLENET) GPS and seismic leg of POLENET spanning West Antarctica and the Transantarctic Mountains deployment of seismographic stations provide new estimates of crustal thickness across West Antarctica, including the West Antarctic Rift System (WARS), Marie Byrd Land (MBL) dome, and the Transantarctic Mountains (TAM) margin. We show that complications arising from ice sheet multiples can be effectively managed and further information concerning low-velocity subglacial sediment thickness may be determined, via top-down utilization of synthetic receiver function models. We combine shallow structure constraints with the response of deeper layers using a regularized Markov chain Monte Carlo methodology to constrain bulk crustal properties. Crustal thickness estimates range from 17.0±4 km at Fishtail Point in the western WARS to 45±5 km at Lonewolf Nunataks in the TAM. Symmetric regions of crustal thinning observed in a transect deployment across the West Antarctic Ice Sheet correlate with deep subice basins, consistent with pure shear crustal necking under past localized extension. Subglacial sediment deposit thicknesses generally correlate with trough/dome expectations, with the thickest inferred subice low-velocity sediment estimated as ˜0.4 km within the Bentley Subglacial Trench. Inverted PRFs from this study and other published crustal estimates are combined with ambient noise surface wave constraints to generate a crustal thickness map for West Antarctica south of 75°S. Observations are consistent with isostatic crustal compensation across the central WARS but indicate significant mantle compensation across the TAM, Ellsworth Block, MBL dome, and eastern and western sectors of thinnest WARS crust, consistent with low density and likely dynamic, low-viscosity high-temperature mantle.

Space weather activities in Australia

NASA Astrophysics Data System (ADS)

Cole, D.

Space Weather Plan Australia has a draft space weather plan to drive and focus appropriate research into services that meet future industry and social needs. The Plan has three main platforms, space weather monitoring and service delivery, support for priority research, and outreach to the community. The details of monitoring, service, research and outreach activities are summarised. A ground-based network of 14 monitoring stations from Antarctica to Papua New Guinea is operated by IPS, a government agency. These sites monitor ionospheric and geomagnetic characteristics, while two of them also monitor the sun at radio and optical wavelengths. Services provided through the Australian Space Forecast Centre (ASFC) include real-time information on the solar, space, ionospheric and geomagnetic environments. Data are gathered automatically from monitoring sites and integrated with data exchanged internationally to create snapshots of current space weather conditions and forecasts of conditions up to several days ahead. IPS also hosts the WDC for Solar-Terrestrial Science and specialises in ground-based solar, ionospheric, and geomagnetic data sets, although recent in-situ magnetospheric measurements are also included. Space weather activities A research consortium operates the Tasman International Geospace Environment Radar (TIGER), an HF southward pointing auroral radar operating from Hobart (Tasmania). A second cooperative radar (Unwin radar) is being constructed in the South Island of New Zealand. This will intersect with TIGER over the auroral zone and enhance the ability of the radar to image the surge of currents that herald space environment changes entering the Polar Regions. Launched in November 2002, the micro satellite FEDSAT, operated by the Cooperative Research Centre for Satellite Systems, has led to successful space science programs and data streams. FEDSAT is making measurements of the magnetic field over Australia and higher latitudes. It also carries a

Antarctotrechus balli sp. n. (Carabidae, Trechini): the first ground beetle from Antarctica

PubMed Central

Ashworth, Allan C; Erwin, Terry L.

2016-01-01

Abstract Fossil elytra of a small trechine carabid are reported from the Oliver Bluffs on the Beardmore Glacier at lat. 85°S. They were compared with counterparts from the extant genera Trechisibus, Tasmanorites, Oxytrechus and Pseudocnides. The fossils share some characters but are sufficiently different to be described as a new genus and species. We named the new species Antarctotrechus balli in honour of George E. Ball who made major contributions to the study of carabids through his own research and the training of students while at the University of Alberta, Edmonton, Alberta, Canada. The closest extant relatives to the extinct Antarctotrechus balli are species of Trechisibus, which inhabit South America, the Falkland Islands and South Georgia, and Tasmanorites, which inhabit Tasmania, Australia. Plant fossils associated with Antarctotrechus balli included Nothofagus (southern beech), Ranunculus (buttercup), moss mats and cushion plants that were part of a tundra biome. Collectively, the stratigraphic relationships and the growth characteristics of the fossil plants indicate that Antarctotrechus balli inhabited the sparsely-vegetated banks of a stream that was part of an outwash plain at the head of a fjord in the Transantarctic Mountains. Other insects represented by fossils in the tundra biome include a listroderine weevil and a cyclorrhaphan fly. The age of the fossils, based on comparison of associated pollen with 40Ar/39Ar dated pollen assemblages from the McMurdo Dry Valleys, is probably Early to Mid-Miocene in the range 14–20 Ma. The tundra biome, including Antarctotrechus balli, became extinct in the interior of Antarctica about 14 Ma and on the margins of the continent by 10–13 Ma. Antarctotrechus balli confirms that trechines were once widely distributed in Gondwana. For Antarctotrechus balli and other elements of the tundra biome it appears they continued to inhabit a warmer Antarctica for many millions of years after rifting of Tasmania (45 Ma

Avian cholera in Southern Great Petrel (Macronectes giganteus) from Antarctica

USGS Publications Warehouse

Leotta, G.A.; Rivas, M.; Chinen, I.; Vigo, G.B.; Moredo, F.A.; Coria, N.; Wolcott, M.J.

2003-01-01

A southern giant petrel (Macronectes giganteus) was found dead at Potter Peninsula, King George Island, South Shetland, Antarctica. The adult male was discovered approximately 48 hr after death. Macroscopic and microscopic lesions were compatible with avian cholera and the bacterium Pasteurella multocida subsp. gallicida, serotype A1 was isolated from lung, heart, liver, pericardial sac, and air sacs. In addition, Escherichia coli was isolated from pericardial sac and air sacs. This is the first known report of avian cholera in a southern giant petrel in Antarctica.

Secular variation and fluctuation of GPS Total Electron Content over Antarctica

NASA Astrophysics Data System (ADS)

Jin, Rui; Jin, Shuanggen

2013-01-01

The total electron content (TEC) is an important parameters in the Earth's ionosphere, related to various space weather and solar activities. However, understanding of the complex ionospheric environments is still a challenge due to the lack of direct observations, particularly in the polar areas, e.g., Antarctica. Now the Global Positioning System (GPS) can be used to retrieve total electron content (TEC) from dual-frequency observations. The continuous GPS observations in Antarctica provide a good opportunity to investigate ionospheric climatology. In this paper, the long-term variations and fluctuations of TEC over Antarctica are investigated from CODE global ionospheric maps (GIM) with a resolution of 2.5°×5° every two hours since 1998. The analysis shows significant seasonal and secular variations in the GPS TEC. Furthermore, the effects of TEC fluctuations are discussed.

Calving of Talyor Glacier, Dry Valleys, Antarctica

NASA Astrophysics Data System (ADS)

Carmichael, J. D.; Pettit, E. C.; Creager, K. C.; Hallet, B.

2007-12-01

Calving of tide-water glaciers has received considerable attention, with seismic arrays in Alaska, Greenland, and Antarctica devoted to their observation. In these environments, ice cliffs are directly coupled to oceanic temperatures. The land-based polar glaciers of the McMurdo Dry Valleys in Antarctica represent a simpler environment unaffected directly by water contact where other factors can be isolated. In particular, summer calving events of Taylor Glacier are observed to consist of precursory activity including crack growth, cliff overhang, and active seismicity at least 1 hour before collapse. We propose that collapse occurs only after a stress threshold has been crossed, evident from 'pre-calving' of ice from the cliff base 1-3 days prior to the major event. We provide photographic, seismic, and temperature data to illustrate the thermal and stress landscape for land-based calving of polar glaciers.

The contents and distributions of cadmium, mercury, and lead in Usnea antarctica lichens from Solorina Valley, James Ross Island (Antarctica).

PubMed

Zvěřina, Ondřej; Coufalík, Pavel; Barták, Miloš; Petrov, Michal; Komárek, Josef

2017-12-11

Lichens are efficient and cost-effective biomonitors of the environment. Their geographic distribution together with their slow growth rate enable investigation of the deposition patterns of various elements and substances. In this research, levels of cadmium, lead, and mercury in Usnea antarctica lichens in the area of James Ross Island, Antarctica, were investigated. The lichens were microwave-digested, and the metals were determined by means of atomic absorption spectrometry with graphite furnace and a direct mercury analyzer. Median total contents of Cd, Hg, and Pb were 0.04, 0.47, and 1.6 mg/kg in whole lichens, respectively. The bottom-up distributions of these metals in the fruticose lichen thalli were investigated, and it was revealed that the accumulation patterns for mercury and lead were opposite to that for cadmium. The probable reason for this phenomenon may lie in the inner structure of thalli. The total contents of metals were comparable with those published for other unpolluted areas of maritime Antarctica. However, this finding was not expected for mercury, since the sampling locality was close to an area with some of the highest mercury contents published for Antarctic lichens. In short, lichens proved their usability as biological monitors, even in harsh conditions. However, the findings emphasize the need to take into account the distributions of elements both in the environment and in the lichen itself.

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

USDA-ARS?s Scientific Manuscript database

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...

Lithospheric Structure of Antarctica and Implications for Geological and Cryospheric Evolution

NASA Astrophysics Data System (ADS)

Wiens, Douglas; Heeszel, David; Sun, Xinlei; Lloyd, Andrew; Nyblade, Andrew; Anandakrishnan, Sridhar; Aster, Richard; Chaput, Julien; Huerta, Audrey; Hansen, Samantha; Wilson, Terry

2013-04-01

Recent broadband seismic deployments, including the AGAP/GAMSEIS array of 24 broadband seismographs over the Gamburtsev Subglacial Mountains (GSM) in East Antarctica and the POLENET/ANET deployment of 33 seismographs across much of West Antarctica, reveal the detailed crust and upper mantle structure of Antarctica for the first time. The seismographs operate year-around even in the coldest parts of Antarctica, due to novel insulated boxes, power systems, and modified instrumentation developed in collaboration with the IRIS PASSCAL Instrument Center. We analyze the data using several different techniques to develop high-resolution models of Antarctic seismic structure. We use Rayleigh wave phase velocities at periods of 20-180 s determined using a modified two-plane wave decomposition of teleseismic Rayleigh waves to invert for the three dimensional shear velocity structure. In addition, Rayleigh wave group and phase velocities obtained by ambient seismic noise correlation methods provide constraints at shorter periods and shallower depths. Receiver functions provide precise estimates of crustal structure beneath the stations, and P and S wave tomography provides models of upper mantle structure down to ~ 500 km depth along transects of greater seismic station density. The new seismic results show that the high elevations of the GSM are supported by thick crust (~ 55 km), and are underlain by thick Precambrian continental lithosphere that initially formed during Archean to mid-Proterozoic times. The absence of lithospheric thermal anomalies suggests that the mountains were formed by a compressional orogeny during the Paleozoic, thus providing a locus for ice sheet nucleation throughout a long period of geological time. Within West Antarctica, the crust and lithosphere are extremely thin near the Transantarctic Mountain Front and topographic lows such as the Bentley Trench and Byrd Basin, which represent currently inactive Cenozoic rift systems. Slow seismic

Genome reconstructions indicate the partitioning of ecological functions inside a phytoplankton bloom in the Amundsen Sea, Antarctica

PubMed Central

Delmont, Tom O.; Eren, A. Murat; Vineis, Joseph H.; Post, Anton F.

2015-01-01

Antarctica polynyas support intense phytoplankton blooms, impacting their environment by a substantial depletion of inorganic carbon and nutrients. These blooms are dominated by the colony-forming haptophyte Phaeocystis antarctica and they are accompanied by a distinct bacterial population. Yet, the ecological role these bacteria may play in P. antarctica blooms awaits elucidation of their functional gene pool and of the geochemical activities they support. Here, we report on a metagenome (~160 million reads) analysis of the microbial community associated with a P. antarctica bloom event in the Amundsen Sea polynya (West Antarctica). Genomes of the most abundant Bacteroidetes and Proteobacteria populations have been reconstructed and a network analysis indicates a strong functional partitioning of these bacterial taxa. Three of them (SAR92, and members of the Oceanospirillaceae and Cryomorphaceae) are found in close association with P. antarctica colonies. Distinct features of their carbohydrate, nitrogen, sulfur and iron metabolisms may serve to support mutualistic relationships with P. antarctica. The SAR92 genome indicates a specialization in the degradation of fatty acids and dimethylsulfoniopropionate (compounds released by P. antarctica) into dimethyl sulfide, an aerosol precursor. The Oceanospirillaceae genome carries genes that may enhance algal physiology (cobalamin synthesis). Finally, the Cryomorphaceae genome is enriched in genes that function in cell or colony invasion. A novel pico-eukaryote, Micromonas related genome (19.6 Mb, ~94% completion) was also recovered. It contains the gene for an anti-freeze protein, which is lacking in Micromonas at lower latitudes. These draft genomes are representative for abundant microbial taxa across the Southern Ocean surface. PMID:26579075

Imprints of a Pan-African transpressional orogen superimposed on an inferred Grenvillian accretionary belt in central East Antarctica

NASA Astrophysics Data System (ADS)

Ferraccioli, Fausto; Seddon, Samuel; Finn, Carol; Bell, Robin; Wu, Guochao; Jordan, Tom

2017-04-01

The Gamburtsev Subglacial Mountains in interior East Antarctica are underlain by 50-60 km thick crust imaged by gravity and seismic models (Ferraccioli et al., 2011; An et al., 2015). In contrast, the composite Archean to Mesoproterozoic Mawson craton that occupies the Wilkes and Terre Adelie sector of East Antarctica typically features only 40-45 km thick crust (Aitken et al., 2014). Over 200 km thick and seismically fast lithosphere underlies the Gamburtsev Province, as typically observed over Precambrian lithosphere that has not been substantially reworked during Phanerozoic subduction or collision. Satellite and airborne magnetic data indicate that the Gamburtev Province is sandwiched in between distinct Precambrian lithospheric blocks including the Ruker, Princess Elizabeth Land, Vostok, Nimrod (Goodge and Finn, 2010), South Pole and Recovery provinces. Ferraccioli et al., (2011) proposed that a segment of a stalled orogen (i.e. an orogen where widespread orogenic collapse and root delamination has not occurred) is preserved in the Gamburtsev Province and further hypothesised that its origin relates to widespread accretionary and subsequent collisional events at ca 1 Ga, linked to the assembly of the Rodinia supercontinent. However, recent passive seismic interpretations (An et al., 2015) indicate that crustal thickening may relate instead to Pan-African age assembly of Greater India, East Antarctica and Australia within Gondwana (at ca 550 Ma). Here we interpret a set of enhanced magnetic and gravity images, depth to magnetic and gravity sources and preliminary 2D and 3D forward and inverse models to characterise in detail the crustal architecture of the Gamburtsev Province. Enhanced aeromagnetic images reveal a system of subglacial faults that segment the Gamburtsev Province into three distinct geophysical domains, the northern, central and southern domains. Apparent offsets in high-frequency magnetic anomalies within the central domain are interpreted here

Topographic Steering of Enhanced Ice Flow at the Bottleneck Between East and West Antarctica

NASA Astrophysics Data System (ADS)

Winter, Kate; Ross, Neil; Ferraccioli, Fausto; Jordan, Tom A.; Corr, Hugh F. J.; Forsberg, René; Matsuoka, Kenichi; Olesen, Arne V.; Casal, Tania G.

2018-05-01

Hypothesized drawdown of the East Antarctic Ice Sheet through the "bottleneck" zone between East and West Antarctica would have significant impacts for a large proportion of the Antarctic Ice Sheet. Earth observation satellite orbits and a sparseness of radio echo sounding data have restricted investigations of basal boundary controls on ice flow in this region until now. New airborne radio echo sounding surveys reveal complex topography of high relief beneath the southernmost Weddell/Ross ice divide, with three subglacial troughs connecting interior Antarctica to the Foundation and Patuxent Ice Streams and Siple Coast ice streams. These troughs route enhanced ice flow through the interior of Antarctica but limit potential drawdown of the East Antarctic Ice Sheet through the bottleneck zone. In a thinning or retreating scenario, these topographically controlled corridors of enhanced flow could however drive ice divide migration and increase mass discharge from interior West Antarctica to the Southern Ocean.

CyberHunt: Head Off to Antarctica.

ERIC Educational Resources Information Center

Kloza, Brad

2001-01-01

Explains how to take an elementary class on a cyber visit to the continent of Antarctica, the highest, driest, and coldest continent on earth. A student reproducible page presents eight web sites to visit in this quest as well as questions to answer about each site. Answers to the questions are included. (SM)

Balloons on Ice: Launch # 2 takes flight in Antarctica

NASA Image and Video Library

2017-12-08

The second of three missions as part of NASA’s Antarctica Long Duration Balloon Flight Campaign was successfully launched at 8:10 a.m. EDT, Dec. 2. The Antarctic Impulsive Transient Antenna (ANITA) from the University of Hawaii at Manoa was launched from Antarctica’s Ross Ice Shelf near McMurdo Station with support from the National Science Foundation’s United States Antarctic Program. Scientists will use ANITA’s instruments to study the reactions in the core of stars and as they explode via the release of neutrinos that travel to Earth and interact with the Antarctica ice. More: go.nasa.gov/2ghR6Le

Low-frequency radar sounder over Glaciers in Alaska, Greenland and Antarctica

NASA Astrophysics Data System (ADS)

Mouginot, J.; Rignot, E. J.; Gim, Y.; Kirchner, D. L.; Merritt, S.; Robison, W. T.

2009-12-01

Ice-thickness and basal layer topography measurements are needed to calculate fluxes through fast-flowing outlet glaciers in Greenland, Alaska, Patagonia and Antarctica. However, relatively high attenuation of radio waves by dielectric absorption and volume scattering from englacial water restrains detection of the bed through warm deep ice. Using a low-frequency (1-5 MHz) airborne radar, we have sounded outlet fast glaciers over Greenland (Store, Upernavik, Hellheim, …), East Antarctica (David, Mertz, Dibble, Byrd, …) and Alaska (Bering, Maslapina, Bagley, …). We will show that we detected the bed through temperate ice up to 1000m thick over Bering and Maslapina Glaciers and also point out difficulty in detecting bed of other Alaska glaciers due to off-nadir returns. We will also make direct comparison of this radar and previous airborne measurements in Greenland and Antarctica in order to discuss a potential improvement of bedrock detectability in temperate ice.

Antarctica: What Shall We Do with It?

ERIC Educational Resources Information Center

Branson, Margaret S.; Long, Cathryn J.

1977-01-01

Describes a role playing exercise in which students act as delegates to a meeting at which they will revise the Antarctic Treaty. Background information is presented about Antarctica, the Antarctic Treaty, and positions of 19 nations with regard to the Treaty. (Author/DB)

Antarctica - Lessons for a Mars exploration program

NASA Technical Reports Server (NTRS)

Mckay, C. P.

1985-01-01

The history of exploration and the international system of control of Antarctica has often been cited as a paradigm for the exploration of space. The small isolated research stations have been used to model the psychological stresses of future space missions. In addition, the programmatic structure of the U.S. Antarctic Research Program provides several possible analogs to future Mars Programs presently under discussion. These are: (1) Continued presence; (2) Civilian, military and private sector involvement; (3) Scientific activities; (4) Risk assessment and logistical support; (5) Accessibility for non-specialists; (6) Political and strategic motivations; (7) International cooperation/competition. Survival in Antarctica is contingent on advanced technology and the active transport of supplies. The scientific exploration of this remote and barren expanse without, of course, the aid and guidance of indigenous people certainly provides one of the closest analogs available to future science activities on the Martian surface.

Widespread surface meltwater drainage in Antarctica

NASA Astrophysics Data System (ADS)

Kingslake, J.; Ely, J.; Das, I.; Bell, R. E.

2016-12-01

Surface meltwater is thought to cause ice-shelf disintegration, which accelerates the contribution of ice sheets to sea-level rise. Antarctic surface melting is predicted to increase and trigger further ice-shelf disintegration during this century. These climate-change impacts could be modulated by an active hydrological network analogous to the one in operation in Greenland. Despite some observations of Antarctic surface and sub-surface hydrological systems, large-scale active surface drainage in Antarctica has rarely been studied. We use satellite imagery and aerial photography to reveal widespread active hydrology on the surface of the Antarctic Ice Sheet as far south as 85o and as high as 1800 m a.s.l., often near mountain peaks that protrude through the ice (nunataks) and relatively low-albedo `blue-ice areas'. Despite predominantly sub-zero regional air temperatures, as simulated by a regional climate model, Antarctic active drainage has persisted for decades, transporting water through surface streams and feeding vast melt ponds up to 80 km long. Drainage networks (the largest are over 100 km in length) form on flat ice shelves, steep outlet glaciers and ice-sheet flanks across the West and East Antarctica Ice Sheets. Motivated by the proximity of many drainage systems to low-albedo rock and blue-ice areas, we hypothesize a positive feedback between exposed-rock extent, BIA formation, melting and ice-sheet thinning. This feedback relies on drainage moving water long distances from areas near exposed rock, across the grounding line onto and across ice shelves - a process we observe, but had previously thought to be unlikely in Antarctica. This work highlights previously-overlooked processes, not captured by current regional-scale models, which may accelerate the retreat of the Antarctic Ice Sheet.

Creole Languages and Educational Development. Linguistic Communications: Working Papers of the Linguistic Society of Australia, No. 13.

ERIC Educational Resources Information Center

Thompson, R.W.

An international conference on creole languages and educational development was held at the University of the West Indies, St. Augustine, Trinidad, from July 24-28, 1972. It was attended by scholars from Africa, Australia, Hawaii, the Caribbean region, the United Kingdom, the United States, and France. The papers presented were descriptions of a…

Gradients in seasonality and seawater oxygen isotopic composition along the early Permian Gondwanan coast, SE Australia

NASA Astrophysics Data System (ADS)

Beard, J. Andrew; Ivany, Linda C.; Runnegar, Bruce

2015-09-01

, suggesting comparatively lower salinity water or more O18-depleted glacial ice/runoff in the Permian Gondwanan high latitudes, perhaps augmented by more depleted (negative) global average seawater. Conditions in southeastern Australia during the largest of the Permian deglaciations were warmer than present-day Antarctica at similar latitudes, but may approximate those of early-mid Miocene Antarctica, with frozen winters but summers closer to 10 °C.

Crustal thickness of Antarctica estimated using data from gravimetric satellites

NASA Astrophysics Data System (ADS)

Llubes, Muriel; Seoane, Lucia; Bruinsma, Sean; Rémy, Frédérique

2018-04-01

Computing a better crustal thickness model is still a necessary improvement in Antarctica. In this remote continent where almost all the bedrock is covered by the ice sheet, seismic investigations do not reach a sufficient spatial resolution for geological and geophysical purposes. Here, we present a global map of Antarctic crustal thickness computed from space gravity observations. The DIR5 gravity field model, built from GOCE and GRACE gravimetric data, is inverted with the Parker-Oldenburg iterative algorithm. The BEDMAP products are used to estimate the gravity effect of the ice and the rocky surface. Our result is compared to crustal thickness calculated from seismological studies and the CRUST1.0 and AN1 models. Although the CRUST1.0 model shows a very good agreement with ours, its spatial resolution is larger than the one we obtain with gravimetric data. Finally, we compute a model in which the crust-mantle density contrast is adjusted to fit the Moho depth from the CRUST1.0 model. In East Antarctica, the resulting density contrast clearly shows higher values than in West Antarctica.

The Southern Cone and Antarctica. Strategies for the 1990’s.

DTIC Science & Technology

1986-01-01

and issued an executive decree on 6 November 1940 ( Decreto No. 1707). The decree laid out the Chilean claim as the lands and ice packs lying between 530...Atlantic (London: British Broadcasting Corp. Publications, 1985), p. 170 . 13Lovering, p. 195. 14Fred Parkinson, "Latin America and Antarctica: An...34Antarctica: A Case for the UN?" World Today 40 (April 1984): 170 -1. Jorge A. Fraga, Introducci6n a la geopolitica antirtica (Buenos Aires: Direcci6n

Direct gravimetric determination of aerosol mass concentration in central antarctica.

PubMed

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.

CSIRO GASLAB Network: Individual Flask Measurements of Atmospheric Trace Gases (April 2003)

DOE Data Explorer

Steele, L. P. [Commonwealth Scientific and Industrial Research Organisation (CSIRO), Aspendale, Victoria, Australia; Krummel, P. R. [Commonwealth Scientific and Industrial Research Organisation (CSIRO), Aspendale, Victoria, Australia; Langenfelds, R. L. [Commonwealth Scientific and Industrial Research Organisation (CSIRO), Aspendale, Victoria, Australia

2003-04-01

Data are available for four atmospheric trace gases at nine stationary sites and one moving platform (aircraft over Cape Grim, Tasmania, and Bass Strait, between the Australian continent and Tasmania). The trace gases are carbon dioxide (CO2), methane (CH4), carbon monoxide (CO), and hydrogen (H2). Measurements of δ13C from CO2 are also included in this database. The nine stationary sites are, from north to south: Alert, Canada; Shetland Islands, Scotland; Estevan Point, Canada; Mauna Loa, Hawaii; Cape Ferguson, Australia; Cape Grim, Australia (Tasmania); Macquarie Island, Australia; Mawson, Antarctica; and the South Pole station, Antarctica.

Bryan Coast, English Coast, Alexander Island, Fallieres Coast, and Bellingshausen Sea, Antarctica

NASA Technical Reports Server (NTRS)

2002-01-01

This image of Antarctica shows the Bryan Coast (lower left), the English Coast (lower central), Alexander Island (middle right), the Fallieres Coast (top right), and the Bellingshausen Sea. The entire continent has been dedicated to peaceful scientific investigation since 1961, with the signing of the Antarctic Treaty.The waters surrounding Antarctica are intensely cold. Salt water freezes at -2C, allowing sea ice to form. The middle left portion of the image shows quite a lot of sea ice in the Bellingshausen Sea. During the Antarctic winter, when data for this image was acquired, Antarctica doubles in size to about 28.5 million square km (or about 11 million square miles), and temperatures in the -60C range are common.This true-color image was compiled from MODIS data gathered March 29, 2002. Credit: Jacques Descloitres, MODIS Land Rapid Response Team, NASA/GSFC

Antarctica and Its Ice Sheet: Knowledge Gained During the IGY/IGC

NASA Astrophysics Data System (ADS)

Bentley, C. R.

2006-12-01

At the end of World War II, the interior of Antarctica, with the exception of the mountains south of the Ross Ice Shelf, was still terra incognita. It was described simply as a nearly continuous high plateau. Even less was known about the ice thickness; the eminent glacial geologist, Richard Foster Flint, believed it "unlikely that the ice thickness exceeds 2000 feet except very locally; probably its average thickness is considerably less." Then in the late 1940's and early 1950's, seismic sounding in Greenland by the Expéditions Polaires Françaises and in Queen Maud Land by the Norwegian-British-Swedish Antarctic Expedition, 1949-52, revealed that, inland of the coastal mountains, the beds in both regions lie close to sea level. This led to a reappraisal of the Antarctic ice sheet, such that the prescient glaciologist, Robert P. Sharp, could predict, on the eve of the IGY, that "between 3000 and 4000 meters of ice will be found" in East Antarctica and that "work during IGY will establish an average thickness for Antarctic inland ice in excess of 1600 m." Seismic and gravity soundings on oversnow traverses conducted by eight countries during the IGY and the succeeding IGC showed Sharp to be basically correct, but there were major surprises, such as the vast Gamburtsev Subglacial Mountains, completely hidden by the ice in central East Antarctica, and the equally vast Byrd Subglacial Basin beneath much of the West Antarctic ice sheet, so deep that roughly half the ice in the region lies below sea level. There were major discoveries on and above the surface too, such as the huge size of the Filchner/Ronne Ice Shelf, and the very existence of the Ellsworth and Pensacola Mountains, the former including the highest peak on the continent. Further, the fundamental difference between the crustal structures of East and West Antarctica became clear. A summary paper published in 1960, looking primarily at West Antarctica where the main U.S. activity lay, could conclude that

Recent Studies on the increase in Seismicity in the Antarctic Plate: Observations from BB Seismological Observatory (MAIT) at Maitri, Antarctica

NASA Astrophysics Data System (ADS)

N, R.; Ec, M.

2008-12-01

The permanent Seismological Observatory was established in 1997 at Maitri in Central Dronning Maud Land, East Antarctica (70 °45' South 11 °43' East) primarily to monitor the seismicity in and around Antarctica, the space and time distribution of earthquake occurrences and obtain hypocentral parameters, magnitudes of earthquakes, velocity inversion for underground structure and earthquake source mechanism. The observatory has been upgraded during 25th Indian Silver Jubilee Scientific Expedition to Antarctica (December 2005 to February 2007) and 26th Indian Antarctic Expedition (IAE) with the new generation Geotech KS-2000M Seismometer and Smart 24R digitizer. During the 27th IAE the Seismic Observatory was further upgraded by adding Reftek 130 seismic system. Uninterrupted good quality digital Broad Band Seismic data is continuously being acquired. The SEISAN 8.1 software was used for final processing and analysis of about 300 earthquakes recorded. During the year 2006 the tele-seismic events, and quite a number of regional earthquakes of the order of 4 to 6.0 magnitude within Antarctic Plate, 23 in South Sandwich Islands, 7 in Scotia Sea, 2 in Macqurie Islands and 23 in Mid Oceanic Ridges in the Indian Ocean were recorded. 48 earthquakes of the magnitude above 4.5 from the nearby South Indian Ocean, South of South Africa, Chile, Argentina, Bolivia and about 40 earthquakes of the magnitude above 5.0 from the Indonesian Region were analysed. An earthquake of magnitude Ms=7.3 from the seismically active region of South Sandwich Islands Δ =16.5 °, Mb=7.8 earthquake from Tonga Islands and Mb=7.2 earthquake from Java were the large earthquakes that were recorded. Along with this the MOHO depth beneath MAIT was also estimated to be about 40km using receiver function analysis. All the analysed monthly data was reported to the I.S.C., U.K.,Global Data Centre for the final processing and inclusion in the yearly ISC Seismic Bulletin. The increasing seismic activity in

Illicit Drug Use and Treatment in South Africa

PubMed Central

Peltzer, Karl; Ramlagan, Shandir; Johnson, Bruce D.; Phaswana-Mafuya, Nancy

2008-01-01

This review synthesizes available epidemiological data on current drug use and substance abuse treatment admissions in south africa since 1994, and how changes in the political, economic and social structures within south africa both before and after apartheid make the country more vulnerable to drug use. based on national surveys current use of cannabis ranged among adolescents from 2% to 9% and among adults 2%, cocaine/crack (0.3%), mandrax/sedatives (0.3%), club drugs/amphetamine-type stimulants (0.2%), opiates (0.1%) and hallucinogens (0.1%). The primary illicit substance at admission to South African drug treatment centers was cannabis 16.9%, methamphetamine (Tik) 12.8%, crack/cocaine 9.6%, cannabis and mandrax 3.4%, heroin/opiates 9.2%, and prescription and OTC 2.6%. An increase in substance abuse treatment admissions has occurred. While the prevalence of illicit drug use in South Africa is relatively low compared to the USA and Australia, prevention and intervention policies need to be designed to reduce these levels by targeting the more risky subpopulations identified from this review. PMID:21039113

Ellsworth mountains: Position in West Antarctica due to sea-floor spreading

USGS Publications Warehouse

Schopf, J.M.

1969-01-01

Similarities of middle and upper Paleozoic deposits of the Ellsworth Mountains with those of the Pensacola, Horlick, and other Transantarctic mountains indicate that all these ranges may have had a related geologic history. A tentative explanation is now suggested which involves sea-floor spreading and translocation of the Ellsworth crustal block from its original location adjacent to the East Antarctic Shield. Accordingly, the islands of West Antarctica may differ in origin and the Transantarctic Mountains of East Antarctica may represent one margin of an ancient rift.

Magnetic anomalies in the Cosmonauts Sea, off East Antarctica

NASA Astrophysics Data System (ADS)

Nogi, Y.; Hanyu, T.; Fujii, M.

2017-12-01

Identification of magnetic anomaly lineations and fracture zone trends in the Southern Indian Ocean, are vital to understanding the breakup of Gondwana. However, the magnetic spreading anomalies and fracture zones are not clear in the Southern Indian Ocean. Magnetic anomaly lineations in the Cosmonauts Sea, off East Antarctica, are key to elucidation of separation between Sri Lanka/India and Antarctica. No obvious magnetic anomaly lineations are observed from a Japanese/German aerogeophysical survey in the Cosmonauts Sea, and this area is considered to be created by seafloor spreading during the Cretaceous Normal Superchron. Vector magnetic anomaly measurements have been conducted on board the Icebreaker Shirase mainly to understand the process of Gondwana fragmentation in the Indian Ocean. Magnetic boundary strikes are derived from vector magnetic anomalies obtained in the Cosmonauts Sea. NE-SW trending magnetic boundary strikes are mainly observed along the several NW-SE oriented observation lines with magnetic anomaly amplitudes of about 200 nT. These NE-SW trending magnetic boundary strikes possibly indicate M-series magnetic anomalies that can not be detected from the aerogeophysical survey with nearly N-S observation lines. We will discuss the magnetic spreading anomalies and breakup process between Sri Lanka/India and Antarctica in the Cosmonauts Sea.

Planetary geomorphology field studies: Iceland and Antarctica

NASA Technical Reports Server (NTRS)

Malin, M. C.

1984-01-01

Field studies of terrestrial landforms and the processes that shape them provide new directions to the study of planetary features. These studies, conducted in Iceland and in Antarctica, investigated physical and chemical weathering mechanisms and rates, eolitan processes, mudflow phenomena, drainage development, and catastrophic fluvial and volcanic phenomena. Continuing investigations in Iceland fall in three main catagories: (1) catastrophic floods of the Jokulsa a Fjollum, (2) lahars associated with explosive volcanic eruptions of Askja caldera, and (3) rates of eolian abrasion in cold, volcanic deserts. The ice-free valleys of Antarctica, in particular those in South Victoria Land, have much is common with the surface of Mars. In addition to providing independent support for the application of the Iceland findings to consideration of the martian erosional system, the Antarctic observations also provide analogies to other martian phenomena. For example, a family of sand dunes in Victoria Valley are stabilized by the incorporation of snow as beds.

Ecological drivers of soil microbial diversity and soil biological networks in the Southern Hemisphere.

PubMed

Delgado-Baquerizo, Manuel; Reith, Frank; Dennis, Paul G; Hamonts, Kelly; Powell, Jeff R; Young, Andrew; Singh, Brajesh K; Bissett, Andrew

2018-03-01

The ecological drivers of soil biodiversity in the Southern Hemisphere remain underexplored. Here, in a continental survey comprising 647 sites, across 58 degrees of latitude between tropical Australia and Antarctica, we evaluated the major ecological patterns in soil biodiversity and relative abundance of ecological clusters within a co-occurrence network of soil bacteria, archaea and eukaryotes. Six major ecological clusters (modules) of co-occurring soil taxa were identified. These clusters exhibited strong shifts in their relative abundances with increasing distance from the equator. Temperature was the major environmental driver of the relative abundance of ecological clusters when Australia and Antarctica are analyzed together. Temperature, aridity, soil properties and vegetation types were the major drivers of the relative abundance of different ecological clusters within Australia. Our data supports significant reductions in the diversity of bacteria, archaea and eukaryotes in Antarctica vs. Australia linked to strong reductions in temperature. However, we only detected small latitudinal variations in soil biodiversity within Australia. Different environmental drivers regulate the diversity of soil archaea (temperature and soil carbon), bacteria (aridity, vegetation attributes and pH) and eukaryotes (vegetation type and soil carbon) across Australia. Together, our findings provide new insights into the mechanisms driving soil biodiversity in the Southern Hemisphere. © 2018 by the Ecological Society of America.

Terranes and the tectonic assembly of South America: The fifth Circum-Pacific terrane conference

NASA Astrophysics Data System (ADS)

Moore, G. W.

1994-10-01

A central theme of the 5th Circum-Pacific Terrane Conference held at Santiago, Chile, 11-14 November 1991, was the new theory that Australia and Antarctica separated from western North America during the Late Proterozoic, then crashed into Africa and South America to form Gondwana in the Late Cambrian. Particular interest centered on the Precordillera Terrane, which came from central North America and was accreted to Argentina during the Ordovician, and on the Avalon Terrane, derived from northern South American and accreted to Laurasia during the Taconic Orogeny. The mobility of plates and terranes has been so great that before the Mesozoic the Circum-Pacific and Circum-Atlantic regions were one and the same.

The Place of Transformative Learning in the Building of Learning Cities in Africa

ERIC Educational Resources Information Center

Biao, Idowu

2013-01-01

This article argues that the learning city concept, which is an international initiative devoted to the promotion of sustainable, healthy, green and economically viable cities by the means of lifelong learning, is currently operational in Europe, the Americas, Australia and Asia but absent in Africa. The main point made by the article is that the…

Estimating Antarctica land topography from GRACE gravity and ICESat altimetry data

NASA Astrophysics Data System (ADS)

Wu, I.; Chao, B. F.; Chen, Y.

2009-12-01

We propose a new method combining GRACE (Gravity Recovery and Climate Experiment) gravity and ICESat (Ice, Cloud, and land Elevation Satellite) altimetry data to estimate the land topography for Antarctica. Antarctica is the fifth-largest continent in the world and about 98% of Antarctica is covered by ice, where in-situ measurements are difficult. Some experimental airborne radar and ground-based radar data have revealed very limited land topography beneath heavy ice sheet. To estimate the land topography for the full coverage of Antarctica, we combine GRACE data that indicate the mass distribution, with data of ICESat laser altimetry that provide high-resolution mapping of ice topography. Our approach is actually based on some geological constraints: assuming uniform densities of the land and ice considering the Airy-type isostasy. In the beginning we construct an initial model for the ice thickness and land topography based on the BEDMAP ice thickness and ICESat data. Thereafter we forward compute the model’s gravity field and compare with the GRACE observed data. Our initial model undergoes the adjustments to improve the fit between modeled results and the observed data. Final examination is done by comparing our results with previous but sparse observations of ice thickness to reconfirm the reliability of our results. As the gravitational inversion problem is non-unique, our estimating result is just one of all possibilities constrained by available data in optimal way.

Challenges in protecting the wilderness of Antarctica

Treesearch

Tina Tin; Alan Hemmings

2011-01-01

Since 1998, the wilderness values of Antarctica have been among those given legal recognition under the Protocol on Environmental Protection to the Antarctic Treaty. Despite the legal obligation, on-the-ground implementation has attracted little interest. The term "wilderness" and its consequential operational implication, including the designation of...

An Evaluation of Antarctica as a Calibration Target for Passive Microwave Satellite Missions

NASA Technical Reports Server (NTRS)

Kim, Edward

2012-01-01

Passive microwave remote sensing at L-band (1.4 GHz) is sensitive to soil moisture and sea surface salinity, both important climate variables. Science studies involving these variables can now take advantage of new satellite L-band observations. The first mission with regular global passive microwave observations at L-band is the European Space Agency's Soil Moisture and Ocean Salinity (SMOS), launched November, 2009. A second mission, NASA's Aquarius, was launched June, 201l. A third mission, NASA's Soil Moisture Active Passive (SMAP) is scheduled to launch in 2014. Together, these three missions may provide a decade-long data record -- provided that they are intercalibrated. The intercalibration is best performed at the radiance (brightness temperature) level, and Antarctica is proving to be a key calibration target. However, Antarctica has thus far not been fully characterized as a potential target. This paper will present evaluations of Antarctica as a microwave calibration target for the above satellite missions. Preliminary analyses have identified likely target areas, such as the vicinity of Dome-C and larger areas within East Antarctica. Physical sources of temporal and spatial variability of polar firn are key to assessing calibration uncertainty. These sources include spatial variability of accumulation rate, compaction, surface characteristics (dunes, micro-topography), wind patterns, and vertical profiles of density and temperature. Using primarily SMOS data, variability is being empirically characterized and attempts are being made to attribute observed variability to physical sources. One expected outcome of these studies is the potential discovery of techniques for remotely sensing--over all of Antarctica--parameters such as surface temperature.

Transcriptomic response of the Antarctic pteropod Limacina helicina antarctica to ocean acidification.

PubMed

Johnson, Kevin M; Hofmann, Gretchen E

2017-10-23

Ocean acidification (OA), a change in ocean chemistry due to the absorption of atmospheric CO 2 into surface oceans, challenges biogenic calcification in many marine organisms. Ocean acidification is expected to rapidly progress in polar seas, with regions of the Southern Ocean expected to experience severe OA within decades. Biologically, the consequences of OA challenge calcification processes and impose an energetic cost. In order to better characterize the response of a polar calcifier to conditions of OA, we assessed differential gene expression in the Antarctic pteropod, Limacina helicina antarctica. Experimental levels of pCO 2 were chosen to create both contemporary pH conditions, and to mimic future pH expected in OA scenarios. Significant changes in the transcriptome were observed when juvenile L. h. antarctica were acclimated for 21 days to low-pH (7.71), mid-pH (7.9) or high-pH (8.13) conditions. Differential gene expression analysis of individuals maintained in the low-pH treatment identified down-regulation of genes involved in cytoskeletal structure, lipid transport, and metabolism. High pH exposure led to increased expression and enrichment for genes involved in shell formation, calcium ion binding, and DNA binding. Significant differential gene expression was observed in four major cellular and physiological processes: shell formation, the cellular stress response, metabolism, and neural function. Across these functional groups, exposure to conditions that mimic ocean acidification led to rapid suppression of gene expression. Results of this study demonstrated that the transcriptome of the juvenile pteropod, L. h. antarctica, was dynamic and changed in response to different levels of pCO 2 . In a global change context, exposure of L. h. antarctica to the low pH, high pCO 2 OA conditions resulted in a suppression of transcripts for genes involved in key physiological processes: calcification, metabolism, and the cellular stress response. The

Workshop on Extraterrestrial Materials from Cold and Hot Deserts

NASA Technical Reports Server (NTRS)

Schultz, Ludolf (Editor); Franchi, Ian A. (Editor); Reid, Arch M. (Editor); Zolensky, Michael E. (Editor)

1999-01-01

Since 1969 expeditions from Japan, the United States, and European countries have recovered more than 20,000 meteorite specimens from remote ice fields of Antarctica. They represent approximately 4000-6000 distinct falls, more than all non-Antarctic meteorite falls and finds combined. Recently many meteorite specimens of a new "population" have become available: meteorites from hot deserts. It turned out that suitable surfaces in hot deserts, like the Sahara in Africa, the Nullarbor Plain in Western and South Australia, or desert high plains of the U.S. (e.g., Roosevelt County, New Mexico), contain relatively high meteorite concentrations. For example, the 1985 Catalog of Meteorites of the British Museum lists 20 meteorites from Algeria and Libya. Today, 1246 meteorites finds from these two countries have been published in MetBase 4.0. Four workshops in 1982, 1985, 1988, and 1989 have discussed the connections between Antarctic glaciology and Antarctic meteorites, and the differences between Antarctic meteorites and modern falls. In 1995, a workshop addressed differences between meteorites from Antarctica, hot deserts, and modem falls, and the implications of possible different parent populations, infall rates, and weathering processes. Since 1995 many more meteorites have been recovered from new areas of Antarctica and hot deserts around the world. Among these finds are several unusual and interesting specimens like lunar meteorites or SNCs of probable martian origin. The Annual Meeting of the Meteoritical Society took place in 1999 in Johannesburg, South Africa. As most of the recent desert finds originate from the Sahara, a special workshop was planned prior to this meeting in Africa. Topics discussed included micrometeorites, which have been collected in polar regions as well as directly in the upper atmosphere. The title "Workshop on Extraterrestrial Materials from Cold and Hot Deserts" was chosen and the following points were emphasized: (1) weathering

Relative sea-level rise around East Antarctica during Oligocene glaciation

NASA Astrophysics Data System (ADS)

Stocchi, Paolo; Escutia, Carlota; Houben, Alexander J. P.; Vermeersen, Bert L. A.; Bijl, Peter K.; Brinkhuis, Henk; Deconto, Robert M.; Galeotti, Simone; Passchier, Sandra; Pollard, David; Brinkhuis, Henk; Escutia, Carlota; Klaus, Adam; Fehr, Annick; Williams, Trevor; Bendle, James A. P.; Bijl, Peter K.; Bohaty, Steven M.; Carr, Stephanie A.; Dunbar, Robert B.; Flores, Jose Abel; Gonzàlez, Jhon J.; Hayden, Travis G.; Iwai, Masao; Jimenez-Espejo, Francisco J.; Katsuki, Kota; Kong, Gee Soo; McKay, Robert M.; Nakai, Mutsumi; Olney, Matthew P.; Passchier, Sandra; Pekar, Stephen F.; Pross, Jörg; Riesselman, Christina; Röhl, Ursula; Sakai, Toyosaburo; Shrivastava, Prakash Kumar; Stickley, Catherine E.; Sugisaki, Saiko; Tauxe, Lisa; Tuo, Shouting; van de Flierdt, Tina; Welsh, Kevin; Yamane, Masako

2013-05-01

During the middle and late Eocene (~ 48-34Myr 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 overall reduction in the mass of the ocean caused by the transfer of water to the ice sheet. Here we identify the crustal response to ice-sheet growth by forcing a glacial-hydro isostatic adjustment model with an Antarctic ice-sheet model. We find that the shelf areas around East Antarctica first shoaled as upper mantle material upwelled and a peripheral forebulge developed. The inner shelf subsequently subsided as lithosphere flexure extended outwards from the ice-sheet margins. Consequently the coasts experienced a progressive relative sea-level rise. Our analysis of sediment cores from the vicinity of the Antarctic ice sheet are in agreement with the spatial patterns of relative sea-level change indicated by our simulations. Our results are consistent with the suggestion that near-field processes such as local sea-level change influence the equilibrium state obtained by an ice-sheet grounding line.

Continent-wide risk assessment for the establishment of nonindigenous species in Antarctica

PubMed Central

Chown, Steven L.; Huiskes, Ad H. L.; Gremmen, Niek J. M.; Lee, Jennifer E.; Terauds, Aleks; Crosbie, Kim; Frenot, Yves; Hughes, Kevin A.; Imura, Satoshi; Kiefer, Kate; Lebouvier, Marc; Raymond, Ben; Tsujimoto, Megumu; Ware, Chris; Van de Vijver, Bart; Bergstrom, Dana Michelle

2012-01-01

Invasive alien species are among the primary causes of biodiversity change globally, with the risks thereof broadly understood for most regions of the world. They are similarly thought to be among the most significant conservation threats to Antarctica, especially as climate change proceeds in the region. However, no comprehensive, continent-wide evaluation of the risks to Antarctica posed by such species has been undertaken. Here we do so by sampling, identifying, and mapping the vascular plant propagules carried by all categories of visitors to Antarctica during the International Polar Year's first season (2007–2008) and assessing propagule establishment likelihood based on their identity and origins and on spatial variation in Antarctica's climate. For an evaluation of the situation in 2100, we use modeled climates based on the Intergovernmental Panel on Climate Change's Special Report on Emissions Scenarios Scenario A1B [Nakićenović N, Swart R, eds (2000) Special Report on Emissions Scenarios: A Special Report of Working Group III of the Intergovernmental Panel on Climate Change (Cambridge University Press, Cambridge, UK)]. Visitors carrying seeds average 9.5 seeds per person, although as vectors, scientists carry greater propagule loads than tourists. Annual tourist numbers (∼33,054) are higher than those of scientists (∼7,085), thus tempering these differences in propagule load. Alien species establishment is currently most likely for the Western Antarctic Peninsula. Recent founder populations of several alien species in this area corroborate these findings. With climate change, risks will grow in the Antarctic Peninsula, Ross Sea, and East Antarctic coastal regions. Our evidence-based assessment demonstrates which parts of Antarctica are at growing risk from alien species that may become invasive and provides the means to mitigate this threat now and into the future as the continent's climate changes. PMID:22393003

Cloning and expression of phosphoglycerate mutase from the psychrophilic yeast, Glaciozyma antarctica PI12

NASA Astrophysics Data System (ADS)

Jaafar, Nardiah Rizwana; Bakar, Farah Diba Abu; Murad, Abdul Munir Abdul; Mahadi, Nor Muhammad

2015-09-01

The conversion of 3-phosphoglycerate to 2-phosphoglycerate during glycolysis and gluconeogenesis is catalyzed by phosphoglycerate mutase (PGM). Better understanding of metabolic reactions performed by this enzyme has been studied extensively in prokaryotes and eukaryotes. Here, we report a phosphoglycerate mutase from the psychrophilic yeast, Glaciozyma antarctica. cDNA encoding for PGM from G. antarctica PI12, a psychrophilic yeast isolated from sea ice at Casey Station, Antarctica was amplified. The gene was then cloned into a cloning vector and sequenced, which verified its identity as the gene putatively encoding for PGM. The recombinant protein was expressed in Escherichia coli BL21 (DE3) as inclusion bodies and this was confirmed by SDS-PAGE and Western blot.

Chemical classification of iron meteorites. XI. Multi-element studies of 38 new irons and the high abundance of ungrouped irons from Antarctica

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wasson, J.T.; Ouyang, Xinwei; Wang, Jianmin

1989-03-01

The authors report concentrations of 14 elements in the metal of 38 iron meteorites and a pallasite. The meteorites are classified based on these data and on structural observations. Three samples are paired with previously classified irons; thus, these additional 35 irons raise the number of well-classified, independent iron meteorites to 598. One Yamato iron contains 342 mg/g Ni, the second highest Ni content in an IAB iron after Oktibbeha County. Two small irons from Western Australia appear to be metal nodules from mesosiderites. Several of the new irons are from Antarctica. Of 24 independent irons from Antarctica, 8 aremore » ungrouped. The fraction, 0.333, is much higher than the fraction 0.161 among all 598 classified irons. Statistical tests show that it is highly improbably ({approximately}2.9% probability) that the Antarctic population is a random sample of the larger population. The difference is probably related to the fact that the median mass of Antarctic irons is about two orders of magnitude smaller than that of non-Antarctic irons. It is doubtful that the difference results from fragmentation patterns yielding different size distributions favoring smaller masses among ungrouped irons. More likely is the possibility that smaller meteoroids tend to sample a larger number of asteroidal source regions, perhaps because small meteoroids tend to have higher ejection velocities or because small meteoroids have random-walked a greater increment of orbital semimajor axis away from that of the parent body.« less

Dioszegia antarctica sp. nov. and Dioszegia cryoxerica sp. nov., psychrophilic basidiomycetous yeasts from polar desert soils in Antarctica

USGS Publications Warehouse

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.

From sea to land: assessment of the bio-transport of phosphorus by penguins in Antarctica

NASA Astrophysics Data System (ADS)

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.

Teaching Mixed-Mode: A Case Study in Remote Delivery of Computer Science in Africa

ERIC Educational Resources Information Center

Howell, Sheila; Harris, Michael; Wilkinson, Simon; Zuluaga, Catherine; Voutier, Paul

2004-01-01

In February 2003, RMIT University in Melbourne, Australia, commenced delivery of a Computer Science diploma and degree programme using mixed mode delivery to 250 university students in sub-Saharan Africa, through a World Bank funded project designed for the African Virtual University (AVU). The project is a unique experience made possible by…

Cultural innovation and megafauna interaction in the early settlement of arid Australia.

PubMed

Hamm, Giles; Mitchell, Peter; Arnold, Lee J; Prideaux, Gavin J; Questiaux, Daniele; Spooner, Nigel A; Levchenko, Vladimir A; Foley, Elizabeth C; Worthy, Trevor H; Stephenson, Birgitta; Coulthard, Vincent; Coulthard, Clifford; Wilton, Sophia; Johnston, Duncan

2016-11-10

Elucidating the material culture of early people in arid Australia and the nature of their environmental interactions is essential for understanding the adaptability of populations and the potential causes of megafaunal extinctions 50-40 thousand years ago (ka). Humans colonized the continent by 50 ka, but an apparent lack of cultural innovations compared to people in Europe and Africa has been deemed a barrier to early settlement in the extensive arid zone. Here we present evidence from Warratyi rock shelter in the southern interior that shows that humans occupied arid Australia by around 49 ka, 10 thousand years (kyr) earlier than previously reported. The site preserves the only reliably dated, stratified evidence of extinct Australian megafauna, including the giant marsupial Diprotodon optatum, alongside artefacts more than 46 kyr old. We also report on the earliest-known use of ochre in Australia and Southeast Asia (at or before 49-46 ka), gypsum pigment (40-33 ka), bone tools (40-38 ka), hafted tools (38-35 ka), and backed artefacts (30-24 ka), each up to 10 kyr older than any other known occurrence. Thus, our evidence shows that people not only settled in the arid interior within a few millennia of entering the continent, but also developed key technologies much earlier than previously recorded for Australia and Southeast Asia.

U.S. Geological Survey scientific activities in the exploration of Antarctica: 1995-96 field season

USGS Publications Warehouse

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

2007-01-01

The U.S. Geological Survey (USGS) mapping program in Antarctica is one of the longest continuously funded projects in the United States Antarctic Program (USAP). This is the 46th U.S. expedition to Antarctica in which USGS scientists have participated. The financial support from the National Science Foundation, which extends back to the time of the International Geophysical Year (IGY) in 1956-57, can be attributed to the need for accurate maps of specific field areas or regions where NSF-funded science projects were planned. The epoch of Antarctic exploration during the IGY was being driven by science and, in a spirit of peaceful cooperation, the international scientific community wanted to limit military activities on the continent to logistical support. The USGS, a Federal civilian science agency in the Department of the Interior, had, since its founding in 1879, carried out numerous field-based national (and some international) programs in biology, geology, hydrology, and mapping. Therefore, the USGS was the obvious choice for these tasks, because it already had a professional staff of experienced mapmakers and program managers with the foresight, dedication, and understanding of the need for accurate maps to support the science programs in Antarctica when asked to do so by the U.S. National Academy of Sciences. Public Laws 85-743 and 87-626, signed in August 1958 and in September 1962, respectively, authorized the Secretary, U.S. Department of the Interior, through the USGS, to support mapping and scientific work in Antarctica. The USGS mapping and science programs still play a significant role in the advancement of science in Antarctica today. Antarctica is the planet's 5th largest continent (13.2 million km2 (5.1 million mi2)), it contains the world's largest (of two) remaining ice sheet, and it is considered to be one of the most important scientific laboratories on Earth. This report provides documentation of USGS scientific activities in the exploration of

U.S. Geological Survey scientific activities in the exploration of Antarctica: 2002-03 field season

USGS Publications Warehouse

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

2007-01-01

The U.S. Geological Survey (USGS) mapping program in Antarctica is one of the longest continuously funded projects in the United States Antarctic Program (USAP). This is the 53rd U.S. expedition to Antarctica in which USGS scientists have participated. The financial support from the National Science Foundation, which extends back to the time of the International Geophysical Year (IGY) in 1956–57, can be attributed to the need for accurate maps of specific field areas or regions where NSF-funded science projects were planned. The epoch of Antarctic exploration during the IGY was being driven by science, and, in a spirit of peaceful cooperation, the international scientific community wanted to limit military activities on the continent to logistical support. The USGS, a Federal civilian science agency in the Department of the Interior, had, since its founding in 1879, carried out numerous field-based national (and some international) programs in biology, geology, hydrology, and mapping. Therefore, the USGS was the obvious choice for these tasks, because it already had a professional staff of experienced mapmakers and program managers with the foresight, dedication, and understanding of the need for accurate maps to support the science programs in Antarctica when asked to do so by the U.S. National Academy of Sciences. Public Laws 85-743 and 87-626, signed in August 1958 and in September 1962, respectively, authorized the Secretary, U.S. Department of the Interior, through the USGS, to support mapping and scientific work in Antarctica. The USGS mapping and science programs still play a significant role in the advancement of science in Antarctica today. Antarctica is the planet's 5th largest continent [13.2 million km2 (5.1 million mi2)], it contains the world's largest (of two) remaining ice sheets, and it is considered to be one of the most important scientific laboratories on Earth. This report provides documentation of USGS scientific activities in the

Field evidence of Eros-scale asteroids and impact-forcing of Precambrian geodynamic episodes, Kaapvaal (South Africa) and Pilbara (Western Australia) Cratons

NASA Astrophysics Data System (ADS)

Glikson, Andrew Y.

2008-03-01

The role of asteroid and comet impacts as triggers of mantle-crust processes poses one of the fundamental questions in Earth science. I present direct field evidence for close associations between impact ejecta/fallout units, major unconformities and lithostratigraphic boundaries in Archaean and early Proterozoic terrains, including abrupt changes in the composition of volcanic and sedimentary assemblages across stratigraphic impact boundaries, with implications for the nature and composition of their provenance terrains. As originally observed by D.R. Lowe and G.R. Byerly, in the Barberton Greenstone Belt, eastern Kaapvaal Craton, South Africa, 3.26-3.24 Ga asteroid mega-impact units are closely associated with the abrupt break between an underlying simatic mafic-ultramafic volcanic crust and an overlying association of turbidites, banded iron formations, felsic tuff and conglomerates of continental affinities. Contemporaneous stratigraphic relationships are identified in the Pilbara Craton, Western Australia. Evidence for enrichment of seawater in ferrous iron in the wake of major asteroid impacts reflects emergence of new source terrains, likely dominated by mafic compositions, attributed to impact-triggered oceanic volcanic activity. Relationships between impact and volcanic activity are supported by the onset of major mafic dyke systems associated with ~ 2.48 Ga and possibly the 2.56 Ga mega-impact events.

Onset of deglacial warming in West Antarctica driven by local orbital forcing.

PubMed

2013-08-22

The cause of warming in the Southern Hemisphere during the most recent deglaciation remains a matter of debate. Hypotheses for a Northern Hemisphere trigger, through oceanic redistributions of heat, are based in part on the abrupt onset of warming seen in East Antarctic ice cores and dated to 18,000 years ago, which is several thousand years after high-latitude Northern Hemisphere summer insolation intensity began increasing from its minimum, approximately 24,000 years ago. An alternative explanation is that local solar insolation changes cause the Southern Hemisphere to warm independently. Here we present results from a new, annually resolved ice-core record from West Antarctica that reconciles these two views. The records show that 18,000 years ago snow accumulation in West Antarctica began increasing, coincident with increasing carbon dioxide concentrations, warming in East Antarctica and cooling in the Northern Hemisphere associated with an abrupt decrease in Atlantic meridional overturning circulation. However, significant warming in West Antarctica began at least 2,000 years earlier. Circum-Antarctic sea-ice decline, driven by increasing local insolation, is the likely cause of this warming. The marine-influenced West Antarctic records suggest a more active role for the Southern Ocean in the onset of deglaciation than is inferred from ice cores in the East Antarctic interior, which are largely isolated from sea-ice changes.

Onset of deglacial warming in West Antarctica driven by local orbital forcing

USGS Publications Warehouse

WAIS Divide Project Members,; Fudge, T. J.; Steig, Eric J.; Markle, Bradley R.; Schoenemann, Spruce W.; Ding, Qinghua; Taylor, Kendrick C.; McConnell, Joseph R.; Brook, Edward J.; Sowers, Todd; White, James W. C.; Alley, Richard B.; Cheng, Hai; Clow, Gary D.; Cole-Dai, Jihong; Conway, Howard; Cuffey, Kurt M.; Edwards, Jon S.; Edwards, R. Lawrence; Edwards, Ross; Fegyveresi, John M.; Ferris, David; Fitzpatrick, Joan J.; Johnson, Jay; Hargreaves, Geoffrey; Lee, James E.; Maselli, Olivia J.; Mason, William; McGwire, Kenneth C.; Mitchell, Logan E.; Mortensen, Nicolai B.; Neff, Peter; Orsi, Anais J.; Popp, Trevor J.; Schauer, Andrew J.; Severinghaus, Jeffrey P.; Sigl, Michael; Spencer, Matthew K.; Vaughn, Bruce H.; Voigt, Donald E.; Waddington, Edwin D.; Wang, Xianfeng; Wong, Gifford J.

2013-01-01

The cause of warming in the Southern Hemisphere during the most recent deglaciation remains a matter of debate. Hypotheses for a Northern Hemisphere trigger, through oceanic redistributions of heat, are based in part on the abrupt onset of warming seen in East Antarctic ice cores and dated to 18,000 years ago, which is several thousand years after high-latitude Northern Hemisphere summer insolation intensity began increasing from its minimum, approximately 24,000 years ago. An alternative explanation is that local solar insolation changes cause the Southern Hemisphere to warm independently. Here we present results from a new, annually resolved ice-core record from West Antarctica that reconciles these two views. The records show that 18,000 years ago snow accumulation in West Antarctica began increasing, coincident with increasing carbon dioxide concentrations, warming in East Antarctica and cooling in the Northern Hemisphere associated with an abrupt decrease in Atlantic meridional overturning circulation. However, significant warming in West Antarctica began at least 2,000 years earlier. Circum-Antarctic sea-ice decline, driven by increasing local insolation, is the likely cause of this warming. The marine-influenced West Antarctic records suggest a more active role for the Southern Ocean in the onset of deglaciation than is inferred from ice cores in the East Antarctic interior, which are largely isolated from sea-ice changes.

Long-range transport of pollutants to the Falkland Islands and Antarctica: evidence from lake sediment fly ash particle records.

PubMed

Rose, Neil L; Jones, Vivienne J; Noon, Philippa E; Hodgson, Dominic A; Flower, Roger J; Appleby, Peter G

2012-09-18

(210)Pb-dated sediment cores taken from lakes on the Falkland Islands, the South Orkney Islands, and the Larsemann Hills in Antarctica were analyzed for fly ash particles to assess the temporal record of contamination from high temperature fossil-fuel combustion sources. Very low, but detectable, levels were observed in the Antarctic lakes. In the Falkland Island lakes, the record of fly ash extended back to the late-19th century and the scale of contamination was considerably higher. These data, in combination with meteorological, modeling, and fossil-fuel consumption data, indicate most likely sources are in South America, probably Chile and Brazil. Other southern hemisphere sources, notably from Australia, contribute to a background contamination and were more important historically. Comparing southern polar data with the equivalent from the northern hemisphere emphasizes the difference in contamination of the two circumpolar regions, with the Falkland Island sites only having a level of contamination similar to that of northern Svalbard.

Life on ice, Antarctica and Mars

NASA Technical Reports Server (NTRS)

Anderson, D. T.; Mckay, C. P.; Wharton, Robert A., Jr.; Sagan, C.; Squyres, S. W.; Simmons, G. M.

1991-01-01

The study of the origin of life and the prospects for human exploration of Mars are two themes developed in a new 57-minute film, Life on Ice, Antarctica, and Mars, produced by the InnerSpace Foundation and WHRO Television for broadcast by the Public Broadcasting System (PBS). A brief explanation of the film and how it relates to the future human exploration of space is presented.

Antarctica Meta-Analysis: Psychosocial Factors Related to Long Duration Isolation and Confinement

NASA Technical Reports Server (NTRS)

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.

Pine Island Glacier, Antarctica, MISR Multi-angle Composite

NASA Image and Video Library

2013-11-15

NASA Terra satellite passed over the Pine Island Glacier in Antarctica around Oct. 27, 2013, just days before iceberg B-31 broke completely free. B-31 is finally moving away from the coast, with open water between the iceberg and the glacier.

Deception Island, Antarctica, harbors a diverse assemblage of wood decay fungi.

PubMed

Held, Benjamin W; Blanchette, Robert A

2017-02-01

Very little is known about fungal diversity in Antarctica as compared to other biomes and how these important organisms function in this unusual ecosystem. Perhaps one of the most unusual ecosystems is that of Deception Island; an active volcanic island part of the South Shetland Islands of the Antarctic Peninsula. Here we describe the fungal diversity associated with historic wood from structures on the island, which reveals a diverse fungal assemblage of known wood decay fungi as well as the discovery of undescribed species. The major group of wood decay fungi identified were species of Cadophora and as shown in previous studies in other geographic regions of Antarctica, they caused a soft-rot type of decay in the introduced woods. Additionally, unlike other areas of Antarctica that have been studied, filamentous basidiomycetes (Hypochniciellum spp. and Pholiota spp.) were also identified that have different modes of degradation including brown and white rot. Matches of fungal sequences to known species in temperate regions likely introduced on building materials indicates human influences and volcanic activity have greatly impacted fungal diversity. Lahars (mudslides from volcanic activity) have partially buried many of the structures and the buried environment as well as the moist, warm soils provided conditions conducive for fungal growth that are not found in other regions of Antarctica. The diverse assemblage of decay fungi and different forms of wood decomposition add to the difficulty of conserving wooden structures at these important polar heritage sites. Copyright © 2016 British Mycological Society. Published by Elsevier Ltd. All rights reserved.

Microbial ecology of terrestrial Antarctica: Are microbial systems at risk from human activities?

DOE Office of Scientific and Technical Information (OSTI.GOV)

White, G.J.

1996-08-01

Many of the ecological systems found in continental Antarctica are comprised entirely of microbial species. Concerns have arisen that these microbial systems might be at risk either directly through the actions of humans or indirectly through increased competition from introduced species. Although protection of native biota is covered by the Protocol on Environmental Protection to the Antarctic Treaty, strict measures for preventing the introduction on non-native species or for protecting microbial habitats may be impractical. This report summarizes the research conducted to date on microbial ecosystems in continental Antarctica and discusses the need for protecting these ecosystems. The focus ismore » on communities inhabiting soil and rock surfaces in non-coastal areas of continental Antarctica. Although current polices regarding waste management and other operations in Antarctic research stations serve to reduce the introduction on non- native microbial species, importation cannot be eliminated entirely. Increased awareness of microbial habitats by field personnel and protection of certain unique habitats from physical destruction by humans may be necessary. At present, small-scale impacts from human activities are occurring in certain areas both in terms of introduced species and destruction of habitat. On a large scale, however, it is questionable whether the introduction of non-native microbial species to terrestrial Antarctica merits concern.« less

Occurrence of arbuscular mycorrhizal fungi on King George Island, South Shetland Islands, Antarctica.

PubMed

Barbosa, Marisângela V; Pereira, Elismara A; Cury, Juliano C; Carneiro, Marco A C

2017-01-01

Arbuscular mycorrhizal fungi make up an important ecological niche in ecosystems, and knowledge of their diversity in extreme environments is still incipient. The objective of this work was to evaluate the density and diversity of arbuscular mycorrhizal fungi in the soil of King George Island in the South Shetland Islands archipelago, Antarctica. For that, soil and roots of Deschampsia antarctica were collected at the brazilian research station in Antarctica. The spore density, species diversity and mycorrhizal colonization in the roots were evaluated. There was a low density of spores (27.4 ± 17.7) and root mycorrhizal colonization (6 ± 5.1%), which did not present statistical difference. Four species of arbuscular mycorrhizal fungi were identified, distributed in two genera: three species of the genus Glomus (Glomus sp1, Glomus sp2 and Glomus sp3) and one of the genus Acaulospora, which was identified at species level (Acaulospora mellea). Greater soil diversity was verified with pH 5.9 and phosphorus concentration of 111 mg dm-3, occurring two species of genus Glomus and A. mellea. Based on literature data, this may be the first record of this species of Acaulospora mellea in Antarctic soils, colonizing D. antarctica plants.

An outline of the palaeogeographic evolution of the Australasian region since the beginning of the Neoproterozoic

NASA Astrophysics Data System (ADS)

Li, Z. X.; Powell, C. McA.

2001-04-01

In the last 1000 million years, Australia has been part of two supercontinents: Palaeozoic Gondwanaland and Neoproterozoic Rodinia. Neoproterozoic Australia was covered by shallow epicontinental seas, and, in the late Neoproterozoic, by low-latitude glaciers. The breakup of Rodinia along the Tasman Line occurred at the end of the Sturtian glaciation (760 Ma) giving rise to the Palaeo-Pacific Ocean. Gondwanaland formed in the Early Cambrian, at the same time as the Tarim block broke away from northwestern Australia. Westward subduction of the Palaeo-Pacific Ocean along the eastern margin of Australia-Antarctica commenced during the Early Cambrian in northern Victoria Land and in the Middle Cambrian in South Australia, and culminated to the Late Cambrian-Early Ordovician Ross-Delamerian Mountains. In the Ordovician, the magmatic arc retreated from Australia's then-eastern continental margin, forming a marginal sea and offshore island arc. A shallow seaway across Australia in the Late Cambrian and Ordovician gradually gave way to desert-like conditions in Central Australia and the adjacent Canning Basin by Silurian time. The Silurian to mid-Devonian was an interval of rapidly changing palaeogeography in eastern Australia with deep volcanogenic troughs formed in a dextral transtensional tectonic setting. Widespread deformation in the Tasman orogenic zone in the Middle Devonian to Early Carboniferous, was accompanied by the development of an Andean-style magmatic arc along the Pacific continental margin of Australia. The most widespread Phanerozoic mountain-building stage in Central Australia occurred in the Late Devonian to mid-Carboniferous, as part of a world-wide Variscan orogenic episode associated with the collision of Gondwanaland with Laurussia to form Pangea. In the late Visean, Australia drifted rapidly southward from previous low latitudes to a near-polar position. Glacial conditions dominated the Late Carboniferous and earliest Permian. Transtensional basins

Southeastern Australia

Atmospheric Science Data Center

2013-04-16

article title:  Drought and Burn Scars in Southeastern Australia     ... related to the dry conditions (not related to the brown burn scars) are also indicated in the February 2003 panel, where many ... 14 and 17, 2002 Images:  Australia Burn Scars location:  Australia and New Zealand ...

Phosphatase activity in Antarctica soil samples as a biosignature of extant life

NASA Astrophysics Data System (ADS)

Sato, Shuji; Itoh, Yuki; Takano, Yoshinori; Fukui, Manabu; Kaneko, Takeo; Kobayashi, Kensei

Microbial activities have been detected in such extreme terrestrial environments as deep lithosphere, a submarine hydrothermal systems, stratosphere, and Antarctica. Microorganisms have adapted to such harsh environments by evolving their biomolecules. Some of these biomolecules such as enzymes might have different characteristics from those of organisms in ordinary environments. Many biosignatures (or biomarkers) have been proposed to detect microbial activities in such extreme environments. A number of techniques are proposed to evaluate biological activities in extreme environments including cultivation methods, assay of metabolism, and analysis of bioorganic compounds like amino acids and DNA. Enzyme activities are useful signature of extant life in extreme environments. Among many enzymes, phosphatase could be a good indicator of biological activities, since phosphate esters are essential for all the living terrestrial organisms. In addition, alkaline phosphatase is known as a typical zinc-containing metalloenzyme and quite stable in environments. We analyzed phosphatase activities in Antarctica soil samples to see whether they can be used as biosignatures for extant life. In addition, we characterized phosphatases extracted from the Antarctica soil samples, and compared with those obtained from other types of environments. Antarctica surface environments are quite severe environments for life since it is extremely cold and dry and exposed to strong UV and cosmic rays. We tried to evaluate biological activities in Antarctica by measuring phosphatase activities. Surface soil samples are obtained at the Sites 1-8 near Showa Base in Antarctica during the 47th Japan Antarctic exploration mission in 2005-6. Activities of acid phosphatase (ACP) and alkaline phosphatase (ALP) are measured spectrophotometrically after mixing the powdered sample and p-nitrophenyl phosphate solution (pH 6.5 for ACP, pH 8.0 for ALP). ALP was characterized after extraction from soils with

First photometric properties of Dome C, Antarctica

NASA Astrophysics Data System (ADS)

Chadid, M.; Vernin, J.; Jeanneaux, F.; Mekarnia, D.; Trinquet, H.

2008-07-01

Here we present the first photometric extinction measurements in the visible range performed at Dome C in Antarctica, using PAIX photometer (Photometer AntarctIca eXtinction). It is made with "off the shelf" components, Audine camera at the focus of Blazhko telescope, a Meade M16 diaphragmed down to 15 cm. For an exposure time of 60 s without filter, a 10th V-magnitude star is measured with a precision of 1/100 mag. A first statistics over 16 nights in August 2007 leads to a 0.5 magnitude per air mass extinction, may be due to high altitude cirrus. This rather simple experiment shows that continuous observations can be performed at Dome C, allowing high frequency resolution on pulsation and asteroseismology studies. Light curves of one of RR Lyrae stars: SAra were established. They show the typical trend of a RRLyrae star. A recent sophisticated photometer, PAIX II, has been installed recently at Dome C during polar summer 2008, with a ST10 XME camera, automatic guiding, auto focusing and Johnson/Bessel UBVRI filter wheels.

Antarctica: Is It More Than Just Ice?

ERIC Educational Resources Information Center

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…

Using 'intimate citizenship' to make sense of the experiences of men with refugee backgrounds in Australia.

PubMed

Muchoki, Samuel

2015-01-01

This paper is based on a study exploring the experiences of men with refugee backgrounds from Sudan, Eritrea, Ethiopia and Somalia (herein referred to as the Horn of Africa countries) during migration and on settlement in Australia. During data analyses, Plummer's concept of 'intimate citizenship' became a useful theoretical framework for understanding participants' experiences. Many men had migrated from traditional societies where individuals pursue intimacies within a constrained framework of acceptability dictated by collective cultures. Ravaged by civil wars, they were forced to flee their homelands and seek asylum in neighbouring countries. Eventually, these men were resettled in Australia, a society that provides a social space for individuals to exercise more choices in their personal lives. On arrival in Australia, participants in this study had to adjust to these new ways of pursuing intimate relationships. Some men found this process overwhelmingly difficult while others saw it as an opportunity to organise their intimate lives beyond the confines of traditions and cultures as well as family and community influences. Intimate citizenship helped in construing the opportunities, conflicts, tensions and ambivalences that characterised participants' experiences in Australia.

Combined Analysis of the Chloroplast Genome and Transcriptome of the Antarctic Vascular Plant Deschampsia antarctica Desv

PubMed Central

Lee, Jungeun; Kang, Yoonjee; Shin, Seung Chul; Park, Hyun; Lee, Hyoungseok

2014-01-01

Background Antarctic hairgrass (Deschampsia antarctica Desv.) is the only natural grass species in the maritime Antarctic. It has been researched as an important ecological marker and as an extremophile plant for studies on stress tolerance. Despite its importance, little genomic information is available for D. antarctica. Here, we report the complete chloroplast genome, transcriptome profiles of the coding/noncoding genes, and the posttranscriptional processing by RNA editing in the chloroplast system. Results The complete chloroplast genome of D. antarctica is 135,362 bp in length with a typical quadripartite structure, including the large (LSC: 79,881 bp) and small (SSC: 12,519 bp) single-copy regions, separated by a pair of identical inverted repeats (IR: 21,481 bp). It contains 114 unique genes, including 81 unique protein-coding genes, 29 tRNA genes, and 4 rRNA genes. Sequence divergence analysis with other plastomes from the BEP clade of the grass family suggests a sister relationship between D. antarctica, Festuca arundinacea and Lolium perenne of the Poeae tribe, based on the whole plastome. In addition, we conducted high-resolution mapping of the chloroplast-derived transcripts. Thus, we created an expression profile for 81 protein-coding genes and identified ndhC, psbJ, rps19, psaJ, and psbA as the most highly expressed chloroplast genes. Small RNA-seq analysis identified 27 small noncoding RNAs of chloroplast origin that were preferentially located near the 5′- or 3′-ends of genes. We also found >30 RNA-editing sites in the D. antarctica chloroplast genome, with a dominance of C-to-U conversions. Conclusions We assembled and characterized the complete chloroplast genome sequence of D. antarctica and investigated the features of the plastid transcriptome. These data may contribute to a better understanding of the evolution of D. antarctica within the Poaceae family for use in molecular phylogenetic studies and may also help researchers understand the

Combined analysis of the chloroplast genome and transcriptome of the Antarctic vascular plant Deschampsia antarctica Desv.

PubMed

Lee, Jungeun; Kang, Yoonjee; Shin, Seung Chul; Park, Hyun; Lee, Hyoungseok

2014-01-01

Antarctic hairgrass (Deschampsia antarctica Desv.) is the only natural grass species in the maritime Antarctic. It has been researched as an important ecological marker and as an extremophile plant for studies on stress tolerance. Despite its importance, little genomic information is available for D. antarctica. Here, we report the complete chloroplast genome, transcriptome profiles of the coding/noncoding genes, and the posttranscriptional processing by RNA editing in the chloroplast system. The complete chloroplast genome of D. antarctica is 135,362 bp in length with a typical quadripartite structure, including the large (LSC: 79,881 bp) and small (SSC: 12,519 bp) single-copy regions, separated by a pair of identical inverted repeats (IR: 21,481 bp). It contains 114 unique genes, including 81 unique protein-coding genes, 29 tRNA genes, and 4 rRNA genes. Sequence divergence analysis with other plastomes from the BEP clade of the grass family suggests a sister relationship between D. antarctica, Festuca arundinacea and Lolium perenne of the Poeae tribe, based on the whole plastome. In addition, we conducted high-resolution mapping of the chloroplast-derived transcripts. Thus, we created an expression profile for 81 protein-coding genes and identified ndhC, psbJ, rps19, psaJ, and psbA as the most highly expressed chloroplast genes. Small RNA-seq analysis identified 27 small noncoding RNAs of chloroplast origin that were preferentially located near the 5'- or 3'-ends of genes. We also found >30 RNA-editing sites in the D. antarctica chloroplast genome, with a dominance of C-to-U conversions. We assembled and characterized the complete chloroplast genome sequence of D. antarctica and investigated the features of the plastid transcriptome. These data may contribute to a better understanding of the evolution of D. antarctica within the Poaceae family for use in molecular phylogenetic studies and may also help researchers understand the characteristics of the chloroplast

Transcriptome of the Antarctic amphipod Gondogeneia antarctica and its response to pollutant exposure.

PubMed

Kang, Seunghyun; Kim, Sanghee; Park, Hyun

2015-12-01

Gondogeneia antarctica is widely distributed off the western Antarctic Peninsula and is a key species in the Antarctic food web. In this study, we performed Illumina sequencing to produce a total of 4,599,079,601 (4.6Gb) nucleotides and a comprehensive transcript dataset for G. antarctica. Over 46 million total reads were assembled into 20,749 contigs, and 12,461 annotated genes were predicted by Blastx. The RNA-seq results after exposure to three pollutants showed that 658, 169 and 367 genes that were potential biomarkers of responses to pollutants for this species were specifically upregulated after exposure to PCBs (Polychlorinated biphenyls), PFOS (Perfluorooctanesulfonic acid) and PFOA (Perfluorooctanoic acid), respectively. These data represent the first transcriptome resource for the Antarctic amphipod G. antarctica and provide a useful resource for studying Antarctic marine species. Copyright © 2015 Elsevier B.V. All rights reserved.

Modelling of mineral dust for interglacial and glacial climate conditions with a focus on Antarctica

DOE PAGES

Sudarchikova, Natalia; Mikolajewicz, Uwe; Timmreck, C.; ...

2015-05-19

The mineral dust cycle responds to climate variations and plays an important role in the climate system by affecting the radiative balance of the atmosphere and modifying biogeochemistry. Polar ice cores provide unique information about deposition of aeolian dust particles transported over long distances. These cores are a palaeoclimate proxy archive of climate variability thousands of years ago. The current study is a first attempt to simulate past interglacial dust cycles with a global aerosol–climate model ECHAM5-HAM. The results are used to explain the dust deposition changes in Antarctica in terms of quantitative contribution of different processes, such as emission,more » atmospheric transport and precipitation, which will help to interpret palaeodata from Antarctic ice cores. The investigated periods include four interglacial time slices: the pre-industrial control (CTRL), mid-Holocene (6000 yr BP; hereafter referred to as \\"6 kyr\\"), last glacial inception (115 000 yr BP; hereafter \\"115 kyr\\") and Eemian (126 000 yr BP; hereafter \\"126 kyr\\"). One glacial time interval, the Last Glacial Maximum (LGM) (21 000 yr BP; hereafter \\"21 kyr\\"), was simulated as well to be a reference test for the model. Results suggest an increase in mineral dust deposition globally, and in Antarctica, in the past interglacial periods relative to the pre-industrial CTRL simulation. Approximately two-thirds of the increase in the mid-Holocene and Eemian is attributed to enhanced Southern Hemisphere dust emissions. Slightly strengthened transport efficiency causes the remaining one-third of the increase in dust deposition. The moderate change in dust deposition in Antarctica in the last glacial inception period is caused by the slightly stronger poleward atmospheric transport efficiency compared to the pre-industrial. Maximum dust deposition in Antarctica was simulated for the glacial period. LGM dust deposition in Antarctica is substantially increased due to 2.6 times

Phylogenomic Analysis Reveals an Asian Origin for African Burkholderia pseudomallei and Further Supports Melioidosis Endemicity in Africa.

PubMed

Sarovich, Derek S; Garin, Benoit; De Smet, Birgit; Kaestli, Mirjam; Mayo, Mark; Vandamme, Peter; Jacobs, Jan; Lompo, Palpouguini; Tahita, Marc C; Tinto, Halidou; Djaomalaza, Innocente; Currie, Bart J; Price, Erin P

2016-01-01

Burkholderia pseudomallei, an environmental bacterium that causes the deadly disease melioidosis, is endemic in northern Australia and Southeast Asia. An increasing number of melioidosis cases are being reported in other tropical regions, including Africa and the Indian Ocean islands. B. pseudomallei first emerged in Australia, with subsequent rare dissemination event(s) to Southeast Asia; however, its dispersal to other regions is not yet well understood. We used large-scale comparative genomics to investigate the origins of three B. pseudomallei isolates from Madagascar and two from Burkina Faso. Phylogenomic reconstruction demonstrates that these African B. pseudomallei isolates group into a single novel clade that resides within the more ancestral Asian clade. Intriguingly, South American strains reside within the African clade, suggesting more recent dissemination from West Africa to the Americas. Anthropogenic factors likely assisted in B. pseudomallei dissemination to Africa, possibly during migration of the Austronesian peoples from Indonesian Borneo to Madagascar ~2,000 years ago, with subsequent genetic diversity driven by mutation and recombination. Our study provides new insights into global patterns of B. pseudomallei dissemination and adds to the growing body of evidence of melioidosis endemicity in Africa. Our findings have important implications for melioidosis diagnosis and management in Africa. IMPORTANCE Sporadic melioidosis cases have been reported in the African mainland and Indian Ocean islands, but until recently, these regions were not considered areas where B. pseudomallei is endemic. Given the high mortality rate of melioidosis, it is crucial that this disease be recognized and suspected in all regions of endemicity. Previous work has shown that B. pseudomallei originated in Australia, with subsequent introduction into Asia; however, the precise origin of B. pseudomallei in other tropical regions remains poorly understood. Using

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

USGS Publications Warehouse

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

2007-01-01

3) significant changes that have occurred in Antarctic exploration and research since World War II will be discussed at the end of this report. Subsequent Open-File Reports will provide a year-by-year documentation of USGS scientific activities and accomplishments in Antarctica beginning with the post-IGY, 1959-60 research team. One Open-File Report is planned to be written for each field-based season. For an example of the series format, see Open-File Reports 2006-1113 (Meunier, 2007a) and 2006-1114 (Meunier, 2007b). This report is a companion document to Open-File Report 2006-1116 (Meunier, 2007c). The USGS mapping and science programs in Antarctica are among the longest continuously funded projects in the United States Antarctic Program (USAP). The 2005-06 field season is the 56th consecutive U.S. expedition in which USGS scientists have been participants, starting in 1946. USGS and the National Science Foundation (NSF) cooperation began with the establishment by NSF of the U.S. Antarctic (Research) Program [USA(R)P] in 1958-59 under Operation Deep Freeze IV (DF IV) and was given the responsibility for the principal coordination and management of all U.S. scientific activities in Antarctica in Deep Freeze 60 (DF 60) (1959-60). Financial support from NSF, mostly in the form of Memorandum of Understandings (MOUs) and Cooperative Agreements, extends back to this period and can be attributed to the need for accurate geologic, geophysical, and topographic base maps of specific field areas or regions where NSF-funded science projects were planned. The epoch of Antarctic exploration during the IGY was driven by science and, in a spirit of peaceful cooperation, the international scientific community wanted to limit military activities on the continent to logistical support (Meunier, 1979 [2007], p. 38). The USGS, a Federal civilian science agency in the Department of the Interior, has, since its founding in 1879, carried out numerous field-based national (and some

Ice crystal precipitation at Dome C site (East Antarctica)

NASA Astrophysics Data System (ADS)

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.

Icefall, Lambert Glacier, Antarctica

NASA Image and Video Library

2017-12-08

Image taken 12/2/2000: The Lambert Glacier in Antarctica, is the world's largest glacier. The focal point of this image is an icefall that feeds into the Lambert glacier from the vast ice sheet covering the polar plateau. Ice flows like water, albeit much more slowly. Cracks can be seen in this icefall as it bends and twists on its slow-motion descent 1300 feet (400 meters) to the glacier below. This Icefall can be found on Landsat 7 WRS Path 42 Row 133/134/135, center: -70.92, 69.15. To learn more about the Landsat satellite go to: landsat.gsfc.nasa.gov/

Detection and Analysis of Complex Patterns of Ice Dynamics in Antarctica from ICESat Laser Altimetry

NASA Astrophysics Data System (ADS)

Babonis, Gregory Scott

There remains much uncertainty in estimating the amount of Antarctic ice mass change, its dynamic component, and its spatial and temporal patterns. This work remedies the limitations of previous studies by generating the first detailed reconstruction of total and dynamic ice thickness and mass changes across Antarctica, from ICESat satellite altimetry observations in 2003-2009 using the Surface Elevation Reconstruction and Change Detection (SERAC) method. Ice sheet thickness changes are calculated with quantified error estimates for each time when ICESat flew over a ground-track crossover region, at approximately 110,000 locations across the Antarctic Ice Sheet. The time series are partitioned into changes due to surficial processes and ice dynamics. The new results markedly improve the spatial and temporal resolution of surface elevation, volume, and mass change rates for the AIS, and can be sampled at annual temporal resolutions. The results indicate a complex spatiotemporal pattern of dynamic mass loss in Antarctica, especially along individual outlet glaciers, and allow for the quantification of the annual contribution of Antarctic ice loss to sea level rise. Over 5000 individual locations exhibit either strong dynamic ice thickness change patterns, accounting for approximately 500 unique spatial clusters that identify regions likely influenced by subglacial hydrology. The spatial distribution and temporal behavior of these regions reveal the complexity and short-time scale variability in the subglacial hydrological system. From the 500 unique spatial clusters, over 370 represent newly identified, and not previously published, potential subglacial water bodies indicating an active subglacial hydrological system over a much larger region than previously observed. These numerous new observations of dynamic changes provide more than simply a larger set of data. Examination of both regional and local scale dynamic change patterns across Antarctica shows newly

Aeromagnetic and radio echo ice-sounding measurements show much greater area of the Dufek intrusion, Antarctica

USGS Publications Warehouse

Behrendt, John C.; Drewry, D.J.; Jankowski, E.; Grim, M.S.

1980-01-01

A combined aeromagnetic and radio echo ice-sounding survey made in 1978 in Antarctica over the Dufek layered mafic intrusion suggests a minimum area of the intrusion of about 50,000 square kilometers, making it comparable in size with the Bushveld Complex of Africa. Comparisons of the magnetic and subglacial topographic profiles illustrate the usefulness of this combination of methods in studying bedrock geology beneath ice-covered areas. Magnetic anomalies range in peak-to-trough amplitude from about 50 nanoteslas over the lowermost exposed portion of the section in the Dufek Massif to about 3600 nanoteslas over the uppermost part of the section in the Forrestal Range. Theoretical magnetic anomalies, computed from a model based on the subice topography fitted to the highest amplitude observed magnetic anomalies, required normal and reversed magnetizations ranging from 10-3 to 10-2 electromagnetic units per cubic centimeter. This result is interpreted as indicating that the Dufek intrusion cooled through the Curie isotherm during one or more reversals of the earth's magnetic field. Copyright ?? 1980 AAAS.

Geophysical investigations of the tectonic boundary between East and West Antarctica

USGS Publications Warehouse

ten Brink, Uri S.; Bannister, S.; Beaudoin, B.C.; Stern, T.A.

1993-01-01

The Transantarctic Mountains (TAM), which separate the West Antarctic rift system from the stable shield of East Antarctica, are the largest mountains developed adjacent to a rift. The cause of uplift of mountains bordering rifts is poorly understood. One notion based on observations of troughs next to many uplifted blocks is that isostatic rebound produces a coeval uplift and subsidence. The results of an over-snow seismic experiment in Antarctica do not show evidence for a trough next to the TAM but indicate the extension of rifted mantle lithosphere under the TAM. Furthermore, stretching preceded the initiation of uplift, which suggests thermal buoyancy as the cause for uplift.

Geodesy in Antarctica: A pilot study based on the TAMDEF GPS network, Victoria Land, Antarctica

NASA Astrophysics Data System (ADS)

Vazquez Becerra, Guadalupe Esteban

The objective of the research presented in this dissertation is a combination of practical and theoretical problems to investigate unique aspects of GPS (Global Positioning System) geodesy in Antarctica. This is derived from a complete analysis of a GPS network called TAMDEF (Trans Antarctic Mountains Deformation), located in Victoria Land, Antarctica. In order to permit access to the International Terrestrial Reference Frame (ITRF), the McMurdo (MCM4) IGS (The International GNSS Service for Geodynamics, formerly the International GPS Service) site was adopted as part of the TAMDEF network. The following scientific achievements obtained from the cited analysis will be discussed as follows: (1) The GPS data processing for the TAMDEF network relied on the PAGES (Program for Adjustment of GPS Ephemerides) software that uses the double-differenced iono-free linear combination, which helps removing a big partial of bias (mm level) in the final positioning. (2) To validate the use of different antenna types in TAMDEF, an antenna testing experiment was conducted using the National Geodetic Survey (NGS) antenna calibration data, appropriate for each antenna type. Sub-daily and daily results from the antenna testing are at the sub-millimeter level, based on the fact that 24-hour solutions were used to average any possible bias. (3) A potential contributor that might have an impact on the TAMDEF stations positioning is the pseudorange multipath effect; thus, the root mean squared variations were estimated and analyzed in order to identify the most and least affected sites. MCM4 was found to be the site with highest multipath, and this is not good at all, since MCM4 is the primary ITRF access point for this part of Antarctica. Additionally, results from the pseudorange multipath can be used for further data cleaning to improve positioning results. (4) The Ocean Tide Modeling relied on the use of two models: CATS02.01 (Circum Antarctic Tidal Simulation) and TPXO6.2 (TOPEX

Diamictite from Nimrod Glacier area, Antarctica: Possible Proterozoic glaciation on the seventh continent

NASA Astrophysics Data System (ADS)

Stump, Edmund; Miller, Julia M. G.; Korsch, Russell J.; Edgerton, David G.

1988-03-01

Late Proterozoic glacial deposits have been found on all continents except Antarctica. Here we describe four units of Late Proterozoic diamictite, with a total thickness of about 10m, from Panorama Point, Nimrod Glacier area, Antarctica, which have characteristics compatible with glaciogenic origin. The diamictite occurs within the Goldie Formation, a sequence of marine turbidites, and is associated with a unit of mafic pillow lavas. The diamictite is commonly structureless and in places laminated. Coarse clasts occur as scattered pebbles and cobbles and as pebbly pods and beds. No striated or faceted clasts were found. A few pebbles may pierce the laminae, but a drop-stone origin is uncertain. Deformation and metamorphism have obscured subtleties of original sedimentary structure. Outsize clasts in laminated sandy siltstone (now schistose) suggest a glaciogenic origin for these diamictites, but deposition by mass-flow processes cannot be ruled out. The discovery in Antarctica of possible Late Proterozoic glaciogenic deposits extends their geographic distribution to all of the major continental masses.

How increasing CO2 leads to an increased negative greenhouse effect in Antarctica

NASA Astrophysics Data System (ADS)

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

2015-12-01

CO2 is the strongest anthropogenic forcing agent for climate change since preindustrial times. Like other greenhouse gases, CO2 absorbs terrestrial surface radiation and causes emission from the atmosphere to space. As the surface is generally warmer than the atmosphere, the total long-wave emission to space is commonly less than the surface emission. However, this does not hold true for the high elevated areas of central Antarctica. For this region, the emission to space is higher than the surface emission; and the greenhouse effect of CO2 is around zero or even negative, which has not been discussed so far. We investigated this in detail and show that for central Antarctica an increase in CO2 concentration leads to an increased long-wave energy loss to space, which cools the Earth-atmosphere system. These findings for central Antarctica are in contrast to the general warming effect of increasing CO2.

Mezozooplankton Beneath the Summer Sea Ice in McMurdo Sound, Antarctica: Abundance, Species Composition, and DMSP content

EPA Science Inventory

The Ross Sea Phaeocystis antarctica bloom contributes to a summer increase in under-ice planton biomass in McMurdo Sound, Antarctica. Due to difficulties of under-ice sampling, information on the mesozooplankton in McMurdo Sound is limited. We measured the abundance of mesooopl...

Tectonic development of West Antarctica and its relation to East Antarctica

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dalziel, I.W.D.

1987-09-01

Over several years, the author has compiled data and conducted field research to gain an understanding of the relationship between East and West Antarctica through geologic time. The investigations have focused on the Scotia Arc and the region at the base of the Antarctic Peninsula extending to the Ellsworth, Thiel, and Whitmore mountains. During the 1983-1984 austral summer, US and British geologists began an intensive investigation in the Ellsworth Mountains and Martin Hills, at Mount Smart, and near Siple Station. Field work includes geology, paleomagnetism, geochronology, and geophysics, with radio-echo sounding and aeromagnetic surveys conducted by British geophysicists. This investigationmore » attempts to define the limits of the crustal blocks and determine the tectonic nature of the ice-covered area between them.« less

Tracking human footprints in Antarctica through passive sampling of polycyclic aromatic hydrocarbons in inland lakes.

PubMed

Yao, Yao; Meng, Xiang-Zhou; Wu, Chen-Chou; Bao, Lian-Jun; Wang, Feng; Wu, Feng-Chang; Zeng, Eddy Y

2016-06-01

Freely dissolved polycyclic aromatic hydrocarbons (PAHs) were monitored in seven inland lakes of Antarctica by a polyethylene (PE)-based passive sampling technique, with the objective of tracking human footprints. The measured concentrations of PAHs were in the range of 14-360 ng L(-1) with the highest values concentrated around the Russian Progress II Station, indicating the significance of human activities to the loading of PAHs in Antarctica. The concentrations of PAHs in the inland lakes were in the upper part of the PAHs levels in aquatic environments from remote and background regions across the globe. The composition profiles of PAHs indicated that PAHs in the inland lakes were derived mainly from local oil spills, which was corroborated by a large number of fuel spillage reports from ship and plane crash incidents in Antarctica during recent years. Clearly, local human activities, rather than long-range transport, are the dominant sources of PAH contamination to the inland lakes. Finally, the present study demonstrates the efficacy of PE-based passive samplers for investigating PAHs in the aquatic environment of Antarctica under complex field conditions. Copyright © 2016 Elsevier Ltd. All rights reserved.

Lichensphere: a protected natural microhabitat of the non-lichenised fungal communities living in extreme environments of Antarctica.

PubMed

Santiago, Iara F; Soares, Marco Aurélio; Rosa, Carlos A; Rosa, Luiz H

2015-11-01

We surveyed the diversity, distribution and ecology of non-lichenised fungal communities associated with the Antarctic lichens Usnea antarctica and Usnea aurantiaco-atra across Antarctica. The phylogenetic study of the 438 fungi isolates identified 74 taxa from 21 genera of Ascomycota, Basidiomycota and Zygomycota. The most abundant taxa were Pseudogymnoascus sp., Thelebolus sp., Antarctomyces psychrotrophicus and Cryptococcus victoriae, which are considered endemic and/or highly adapted to Antarctica. Thirty-five fungi may represent new and/or endemic species. The fungal communities displayed high diversity, richness and dominance indices; however, the similarity among the communities was variable. After discovering rich and diverse fungal communities composed of symbionts, decomposers, parasites and endemic and cold-adapted cosmopolitan taxa, we introduced the term "lichensphere". We hypothesised that the lichensphere may represent a protected natural microhabitat with favourable conditions able to help non-lichenised fungi and other Antarctic life forms survive and disperse in the extreme environments of Antarctica.

Airborne laser scanning for high-resolution mapping of Antarctica

NASA Astrophysics Data System (ADS)

Csatho, Bea; Schenk, Toni; Krabill, William; Wilson, Terry; Lyons, William; McKenzie, Garry; Hallam, Cheryl; Manizade, Serdar; Paulsen, Timothy

In order to evaluate the potential of airborne laser scanning for topographic mapping in Antarctica and to establish calibration/validation sites for NASA's Ice, Cloud and land Elevation Satellite (ICESat) altimeter mission, NASA, the U.S. National Science Foundation (NSF), and the U.S. Geological Survey (USGS) joined forces to collect high-resolution airborne laser scanning data.In a two-week campaign during the 2001-2002 austral summer, NASA's Airborne Topographic Mapper (ATM) system was used to collect data over several sites in the McMurdo Sound area of Antarctica (Figure 1a). From the recorded signals, NASA computed laser points and The Ohio State University (OSU) completed the elaborate computation/verification of high-resolution Digital Elevation Models (DEMs) in 2003. This article reports about the DEM generation and some exemplary results from scientists using the geomorphologic information from the DEMs during the 2003-2004 field season.

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

PubMed

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

The impact of lateral variations in lithospheric thickness on glacial isostatic adjustment in West Antarctica

NASA Astrophysics Data System (ADS)

Nield, Grace A.; Whitehouse, Pippa L.; van der Wal, Wouter; Blank, Bas; O'Donnell, John Paul; Stuart, Graham W.

2018-04-01

Differences in predictions of Glacial Isostatic Adjustment (GIA) for Antarctica persist due to uncertainties in deglacial history and Earth rheology. The Earth models adopted in many GIA studies are defined by parameters that vary in the radial direction only and represent a global average Earth structure (referred to as 1D Earth models). Over-simplifying actual Earth structure leads to bias in model predictions in regions where Earth parameters differ significantly from the global average, such as West Antarctica. We investigate the impact of lateral variations in lithospheric thickness on GIA in Antarctica by carrying out two experiments that use different rheological approaches to define 3D Earth models that include spatial variations in lithospheric thickness. The first experiment defines an elastic lithosphere with spatial variations in thickness inferred from seismic studies. We compare the results from this 3D model with results derived from a 1D Earth model that has a uniform lithospheric thickness defined as the average of the 3D lithospheric thickness. Irrespective of deglacial history and sub-lithospheric mantle viscosity, we find higher gradients of present-day uplift rates (i.e. higher amplitude and shorter wavelength) in West Antarctica when using the 3D models, due to the thinner-than-1D-average lithosphere prevalent in this region. The second experiment uses seismically-inferred temperature as input to a power-law rheology thereby allowing the lithosphere to have a viscosity structure. Modelling the lithosphere with a power-law rheology results in behaviour that is equivalent to a thinner-lithosphere model, and it leads to higher amplitude and shorter wavelength deformation compared with the first experiment. We conclude that neglecting spatial variations in lithospheric thickness in GIA models will result in predictions of peak uplift and subsidence that are biased low in West Antarctica. This has important implications for ice-sheet modelling

IPY: Engaging Antarctica: Bringing Antarctic Geoscience to the Public Through a NOVA Documentary and an Innovative Flexible Exhibit for Informal Science Education Venues

NASA Astrophysics Data System (ADS)

Rack, F.; Diamond, J.; Levy, R.; Berg, M.; Dahlman, L.; Jackson, J.

2006-12-01

IPY: Engaging Antarctica is an informal science education project designed to increase the general public's understanding of scientific research conducted in Antarctica. The project focuses specifically on the multi- national, NSF-funded Antarctic Drilling Project (ANDRILL). The ANDRILL project is the newest geological drilling program in an ongoing effort to recover stratigraphic records from Antarctica. ANDRILL's primary objectives are to investigate Antarctica's role in global environmental change over the past 65 million years and to better understand its future response to global changes. Additionally, through ANDRILL's Research Immersion for Science Educators program (ARISE), 12 science educators from four countries will work on science research teams in Antarctica and produce educational materials that feature Antarctic geoscience. The Engaging Antarctica project will produce both a NOVA television documentary and an innovative informal learning exhibit. The documentary, Antarctica's Icy Secrets, will provide a geological perspective on how Antarctica continues to play a major role in affecting global climate by altering ocean currents and sea levels. The learning exhibit, one that blends standards- and inquiry-based learning with the latest information technologies, is coined the Flexhibit. The Engaging Antarctica Flexhibit will provide a digital package of high resolution images for banners as well as learning activities and ideas for exhibit stations that can be implemented by youth groups. Flexhibit images will feature ANDRILL scientists at work, and audio files, available as podcasts, will tell scientists' stories in their own words, speaking directly to the public about the joys and challenges of Antarctic geological research.

Historic First Landing of NASA's P-3B in Antarctica

NASA Image and Video Library

2014-01-03

NASA's first ever historic P-3B landing in McMurdo Station, Antarctica on the sea ice runway, which occurred on Nov. 16, 2013. It took the craft 5 days to reach Antarctica from the NASA Wallops Flight Facility in Wallops Island, Virginia. You can see the IceBridge Team waiting to greet the flight crew as they taxied for the very first time right up to the IceBridge team tents. Credit: NASA/Justin Miller/Indiana University NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

ICE-VOLC Project: unravelling the dynamics of Antarctica volcanoes

NASA Astrophysics Data System (ADS)

Cannata, Andrea; Del Carlo, Paola; Giudice, Gaetano; Giuffrida, Giovanni; Larocca, Graziano; Liuzzo, Marco

2017-04-01

Melbourne and Rittmann volcanoes are located in the Victoria Land. Whilst Rittmann's last eruption dates probably to Pleistocene, Melbourne's most recent eruption between 1862 and 1922, testifying it is still active. At present, both volcanoes display fumarolic activity. Melbourne was discovered in 1841 by James Clark Ross, Rittmann during the 4th Italian Expedition (1988/1989). Our knowledge on both volcanoes is really little. The position of these volcanoes in the Antarctic region (characterised by absence of anthropic noise) and its proximity with the Italian Mario Zucchelli Station makes them ideal sites for studying volcano seismic sources, geothermal emissions, seismo-acoustic signals caused by cryosphere-hydrosphere-atmosphere dynamics, and volcanic gas impact on environment. Hence, the main aim of the ICE-VOLC ("multiparametrIC Experiment at antarctica VOLCanoes: data from volcano and cryosphere-ocean-atmosphere dynamics") project is the study of Melbourne and Rittmann, by acquisition, analysis and integration of multiparametric geophysical, geochemical and thermal data. Complementary objectives include investigation of the relationship between seismo-acoustic activity recorded in Antarctica and cryosphere-hydrosphere-atmosphere dynamics, evaluation of the impact of volcanic gas in atmosphere. This project involves 26 researchers, technologists and technicians from University of Perugia and from Istituto Nazionale di Geofisica e Vulcanologia of Catania, Palermo, Pisa and Rome. In this work, we show the preliminary results obtained after the first expedition in Antarctica, aiming to perform geochemical-thermal surveys in the volcano ice caves, as well as to collect ash samples and to install temporary seismic stations.

Deglacial temperature history of West Antarctica.

PubMed

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

2016-12-13

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 CO 2 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 [Formula: see text]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.

Receiver functions from west Antarctica; crust and mantle properties from POLENET

NASA Astrophysics Data System (ADS)

Aster, R. C.; Chaput, J. A.; Hansen, S. E.; Nyblade, A.; Wiens, D. A.; Huerta, A. D.; Wilson, T. J.; Anandakrishnan, S.

2011-12-01

We use receiver functions to extract crustal thickness and mantle transition zone depths across a wide extent of West Antarctica and the Transantarctic mountains using POLENET data, including recently recovered data from a 14-station West Antarctic Rift Zone transect. An adaptive approach for generating and analyzing P-receiver functions over ice sheets and sedimentary basins (similar to Winberry and Anandakrishnan, 2004) is applied using an extended time multitaper deconvolution algorithm and forward modeling synthetic seismogram fitting. We model P-S receiver functions via a layer stripping methodology (beginning with the ice sheet, if present), and fit increasingly longer sections of synthetic receiver functions to model the multiples observed in the data derived receiver functions. We additionally calculate S-P receiver functions, which provide complementary structural constraints, to generate consistent common conversion point stacks to image crustal and upper mantle discontinuities under West Antarctica. Crust throughout West Antarctica is generally thin (23-29 km; comparable to the U.S. Basin and Range) with relative thickening under the Marie Byrd Land volcanic province (to 32 km) and the Transantarctic Mountains. All constrained west Antarctic crust is substantially thicker than that in the vicinity of Ross Island, where crust as thin as 17 km is inferred in the Terror Rift region.

Pseudonotohymena antarctica n. g., n. sp. (Ciliophora, Hypotricha), a New Species from Antarctic Soil.

PubMed

Park, Kyung-Min; Jung, Jae-Ho; Min, Gi-Sik; Kim, Sanghee

2017-07-01

A new soil ciliate, Pseudonotohymena antarctica n. g., n. sp., from King George Island, Antarctica, is described based on live observation, protargol impregnation, and its 18S rRNA gene. The new genus Pseudonotohymena is morphologically similar to the genus Notohymena Blatterer and Foissner in the following characteristics: 18 fronto-ventral-transverse cirri, a flexible body, undulating membranes, dorsomarginal kineties, and the number of cirri in the marginal rows. However, Pseudonotohymena differs from Notohymena particularly in the dorsal ciliature, that is, in possessing a nonfragmented dorsal kinety (vs. fragmented). In addition, the molecular phylogenetic relationship of the new species differs from that of Notohymena species. On the basis of the morphological features, the genetic data, and morphogenesis, we establish P. antarctica n. g., n. sp. In addition, the cyst morphology of this species is described. © 2016 The Author(s) Journal of Eukaryotic Microbiology © 2016 International Society of Protistologists.

Modern benthic ostracodes from Lutzow-Holm Bay, East Antarctica: paleoceanographic, paleobiogeographic, and evolutionary significance

USGS Publications Warehouse

Yasuhara, Moriaki; Kato, Masako; Ikeya, Noriyuki; Seto, Koji

2007-01-01

Seventy-three ostracode species from 38 genera were recovered from the 55 surface sediment samples in Lützow-Holm Bay, northeastern Antarctica. We investigated bathymetric and geographic distributions of modern benthic ostracode species in the bay and compared this fauna with published modern and fossil ostracode data of Antarctic and southern South American regions. The results show: (1) Four biotopes and three sub-biotopes are recognized based on Q-mode cluster analysis, which suggest distributions of modern ostracodes are mainly controlled by water-mass structure, ice scouring, and light availability. (2) Comparison between the Lützow-Holm Bay fauna and other ostracode faunas from Antarctica and southern South America shows high endemism and homogeneity of Antarctic ostracode fauna, suggesting in situ evolution of most extant Antarctic species. (3) Most species are endemic to the Antarctica, a few species also inhabit South American waters.

Glacial isostatic crustal uplift in southern Victoria Land, Antarctica, from geologic and geodetic records

NASA Astrophysics Data System (ADS)

Konfal, S.; Wilson, T.; Bevis, M. G.; Kendrick, E. C.; Hall, B. L.

2011-12-01

Geologic records and geodetic measurements of glacial isostatic crustal motions are presented from the southern Victoria Land region of Antarctica. In much of the world, key records used for mapping and modeling glacial isostatic crustal motions come from raised paleoshorelines and beaches of ice-marginal lakes and seas. While such records are scarce in Antarctica, preserved paleoshorelines are present in the southern Victoria Land region of Antarctica. Light detection and ranging (LiDAR) data coverages of these features were acquired during the 2001-2002 austral summer field season by NASA's Airborne Topographic Mapper (ATM) system, resulting in 2 meter horizontal resolution digital elevation models (DEMs). This study utilizes these DEM data to derive crustal tilt values from observed changes in elevation along the length of the shorelines. Radiocarbon age data are correlated with the associated degree of shoreline tilt to derive a rate of crustal deformation since deglaciation. Modern rates of glacial isostatic crustal motion are derived from GPS stations in the same region. Campaign station occupation began in 1996-1997 under the TAMDEF (Transantarctic Mountain DEFormation Network) project, and continuous GPS data collected began in 1999 and continues under the ANET/POLENET (Antarctica Polar Earth Observing Network) project, enabling analysis of decadal scale time series. Integrated gradient curves from paleoshoreline records and GPS crustal velocities show exponential form and indicate tilting down to the east. Eastward tilt may be the result of substantial loss of East Antarctic ice, a collapsing forebulge linked to ice centers in the Ross Sea region or in interior West Antarctica, or differences in earth response due to laterally varying earth structure. Modeling of these new data, along with comparison of tilt directions to centers of ice mass loss, provide tests of these scenarios and yield new insights into earth models and ice history.

Ice-shelf melting around Antarctica

NASA Astrophysics Data System (ADS)

Rignot, E.; Jacobs, S.

2008-12-01

The traditional view on the mass balance of Antarctic ice shelves is that they loose mass principally from iceberg calving with bottom melting a much lower contributing factor. Because ice shelves are now known to play a fundamental role in ice sheet evolution, it is important to re-evaluate their wastage processes from a circumpolar perspective using a combination of remote sensing techniques. We present area average rates deduced from grounding line discharge, snow accumulation, firn depth correction and ice shelf topography. We find that ice shelf melting accounts for roughly half of ice-shelf ablation, with a total melt water production of 1027 Gt/yr. The attrition fraction due to in-situ melting varies from 9 to 90 percent around Antarctica. High melt producers include the Ronne, Ross, Getz, Totten, Amery, George VI, Pine Island, Abbot, Dotson/Crosson, Shackleton, Thwaites and Moscow University Ice Shelves. Low producers include the Larsen C, Princess Astrid and Ragnhild coast, Fimbul, Brunt and Filchner. Correlation between melt water production and grounding line discharge is low (R2 = 0.65). Correlation with thermal ocean forcing from the ocean are highest in the northern parts of West Antarctica where regressions yield R2 of 0.93-0.97. Melt rates in the Amundsen Sea exhibit a quadratic sensitivity to thermal ocean forcing. We conclude that ice shelf melting plays a dominant role in ice shelf mass balance, with a potential to change rapidly in response to altered ocean heat transport onto the Antarctic continental shelf.

Antarctica: Arena for South American Cooperation or Conflict.

ERIC Educational Resources Information Center

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.…

Antarctica as a testing ground for manned missions to the Moon and Mars

NASA Astrophysics Data System (ADS)

Demidov, N. E.; Lukin, V. V.

2017-03-01

This paper is concerned with the study of expedition activity in Antarctica as a part of the search for useful analogies and solutions which can be taken into account in planning manned missions to the Moon and Mars. The following is considered: natural analogies, human factors, station facilities, means of transportation, scientific programs, safety issues, and historical and political analogies. A rationalization is given for the idea of creating a testing ground in Antarctica (stations Vostok, Novolazarevskaya, Jetty Oasis) for ground-based simulation of functioning of a lunar and Martian base.

Concordia CCD - A Geoscope station in continental Antarctica

NASA Astrophysics Data System (ADS)

Maggi, A.; Lévêque, J.; Thoré, J.; Bes de Berc, M.; Bernard, A.; Danesi, S.; Morelli, A.; Delladio, A.; Sorrentino, D.; Stutzmann, E.; Geoscope Team

2010-12-01

Concordia (Dome C, Antarctica) has had a permanent seismic station since 2005. It is run by EOST and INGV in collaboration with the French and Italian polar institutes (IPEV and PNRA). It is installed in an ice-vault, at 12m depth, distant 1km from the permanent scientific base at Concordia. The temperature in the vault is a constant -55°C. The data quality at the station has improved continuously since its installation. In 2007, the station was declared at ISC as an open station with station code CCD (ConCorDia), with data available upon request. It is only the second permanent station in the Antarctic continent, after South Pole. In 2010, CCD was included in the Geoscope network. Data from CCD starting in 2007 are now freely available from the Geoscope Data Center and IRIS. We present an analysis of the data quality at CCD, and describe the technical difficulties of operating an observatory-quality seismic station in the extreme environmental conditons present in continental Antarctica.

ECC (Electrochemical Concentration Cell) ozonesonde observations at Mirny, Antarctica, during 1988

NASA Technical Reports Server (NTRS)

Komhyr, W. D.; Lathrop, J. A.; Arbuzova, V. N.; Khattatov, V. U.; Nureyev, P. G.; Rudakov, V. V.; Zamyshlayev, I. V.

1989-01-01

Atmospheric ozone vertical distributions, air temperatures, and wind speed and direction data are presented for 40 balloon electrochemical concentration cell ozone soundings made at Mirny, Antarctica, in 1988.

Blowing Snow Sublimation and Transport over Antarctica from 11 Years of CALIPSO Observations

NASA Technical Reports Server (NTRS)

Palm, Stephen P.; Kayetha, Vinay; Yang, Yuekui; Pauly, Rebecca

2017-01-01

Blowing snow processes commonly occur over the earth's ice sheets when the 10 mile wind speed exceeds a threshold value. These processes play a key role in the sublimation and redistribution of snow thereby influencing the surface mass balance. Prior field studies and modeling results have shown the importance of blowing snow sublimation and transport on the surface mass budget and hydrological cycle of high-latitude regions. For the first time, we present continent-wide estimates of blowing snow sublimation and transport over Antarctica for the period 2006-2016 based on direct observation of blowing snow events. We use an improved version of the blowing snow detection algorithm developed for previous work that uses atmospheric backscatter measurements obtained from the CALIOP (Cloud-Aerosol Lidar with Orthogonal Polarization) lidar aboard the CALIPSO (Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation) satellite. The blowing snow events identified by CALIPSO and meteorological fields from MERRA-2 are used to compute the blowing snow sublimation and transport rates. Our results show that maximum sublimation occurs along and slightly inland of the coastline. This is contrary to the observed maximum blowing snow frequency which occurs over the interior. The associated temperature and moisture reanalysis fields likely contribute to the spatial distribution of the maximum sublimation values. However, the spatial pattern of the sublimation rate over Antarctica is consistent with modeling studies and precipitation estimates. Overall, our results show that the 2006-2016 Antarctica average integrated blowing snow sublimation is about 393 +/- 196 Gt yr(exp -1), which is considerably larger than previous model-derived estimates. We find maximum blowing snow transport amount of 5 Mt km-1 yr(exp -1) over parts of East Antarctica and estimate that the average snow transport from continent to ocean is about 3.7 Gt yr(exp -1). These continent-wide estimates are the

Crustal architecture of the oblique-slip conjugate margins of George V Land and southeast Australia

USGS Publications Warehouse

Stagg, H.M.J.; Reading, A.M.

2007-01-01

A conceptual, lithospheric-scale cross-section of the conjugate, oblique-slip margins of George V Land, East Antarctica, and southeast Australia (Otway Basin) has been constructed based on the integration of seismic and sample data. This cross-section is characterised by asymmetry in width and thickness, and depth-dependent crustal extension at breakup in the latest Maastrichtian. The broad Antarctic margin (~360 km apparent rift width) developed on thick crust (~42 km) of the Antarctic craton, whereas the narrow Otway margin (~220 km) developed on the thinner crust (~31 km) of the Ross–Delamerian Orogen. The shallow basement (velocities ~5.5 km.s-1) and the deep continental crust (velocities >6.4 km.s-1) appear to be largely absent across the central rift, while the mid-crustal, probably granitic layer (velocities ~6 km.s-1) is preserved. Comparison with published numerical models suggests that the shallow basement and deep crust may have been removed by simple shear, whereas the mid-crust has been ductilely deformed.

New Perspectives on Blowing Snow Transport, Sublimation, and Layer Thermodynamic Structure over Antarctica

NASA Technical Reports Server (NTRS)

Palm, Steve; Kayetha, Vinay; Yang, Yuekui; Pauly, Rebecca M.

2017-01-01

Blowing snow over Antarctica is a widespread and frequent event. Satellite remote sensing using lidar has shown that blowing snow occurs over 70% of the time over large areas of Antarctica in winter. The transport and sublimation of blowing snow are important terms in the ice sheet mass balance equation and the latter is also an important part of the hydrological cycle. Until now the only way to estimate the magnitude of these processes was through model parameterization. We present a technique that uses direct satellite observations of blowing snow and model (MERRA-2) temperature and humidity fields to compute both transport and sublimation of blowing snow over Antarctica for the period 2006 to 2016. The results show a larger annual continent-wide integrated sublimation than current published estimates and a significant transport of snow from continent to ocean. The talk will also include the lidar backscatter structure of blowing snow layers that often reach heights of 200 to 300 m as well as the first dropsonde measurements of temperature, moisture and wind through blowing snow layers.

Cloning, expression and crystallisation of SGT1 co-chaperone protein from Glaciozyma antarctica

NASA Astrophysics Data System (ADS)

Yusof, Nur Athirah; Bakar, Farah Diba Abu; Beddoe, Travis; Murad, Abdul Munir Abdul

2013-11-01

Studies on psycrophiles are now in the limelight of today's post genomic era as they fascinate the research and development industries. The discovery from Glaciozyma antarctica, an extreme cold adapted yeast from Antarctica shows promising future to provide cost effective natural sustainable energy and create wider understanding of the property that permits this organisms to adapt to extreme temperature downshift. In plants and yeast, studies show the interaction between SGT1 and HSP90 are essential for disease resistance and heat stress by activating a number of resistance proteins. Here we report for the first time cloning, expression and crystallization of the recombinant SGT1 protein of G. antarctica (rGa_SGT1), a highly conserved eukaryotic protein that interacts with the molecular chaperones HSP90 (heat shock protein 90) apparently associated in a role of co-chaperone that may play important role in cold adaptation. The sequence analysis of rGa_SGT1 revealed the presence of all the characteristic features of SGT1 protein. In this study, we present the outlines and results of protein structural study of G. antarctica SGT1 protein. We validate this approach by starting with cloning the target insert into Ligation Independent Cloning system proceeded with expression using E. coli system, and crystallisation of the target rGA_SGT1 protein. The work is still on going with the target subunit of the complex proteins yielded crystals. These results, still ongoing, open a platform for better understanding of the uniqueness of this crucial molecular machine function in cold adaptation.

Seismic and thermal structure of the crust and uppermost mantle beneath Antarctica from inversion of multiple seismic datasets

NASA Astrophysics Data System (ADS)

Wiens, D.; Shen, W.; Anandakrishnan, S.; Aster, R. C.; Gerstoft, P.; Bromirski, P. D.; Dalziel, I.; Hansen, S. E.; Heeszel, D.; Huerta, A. D.; Nyblade, A.; Stephen, R. A.; Wilson, T. J.; Winberry, J. P.; Stern, T. A.

2017-12-01

Since the last decade of the 20th century, over 200 broadband seismic stations have been deployed across Antarctica (e.g., temporary networks such as TAMSEIS, AGAP/GAMSEIS, POLENET/ANET, TAMNNET and RIS/DRIS by U.S. geoscientists as well as stations deployed by Japan, Britain, China, Norway, and other countries). In this presentation, we discuss our recent efforts to build reference crustal and uppermost mantle shear velocity (Vs) and thermal models for continental Antarctica based on those seismic arrays. By combing the high resolution Rayleigh wave dispersion maps derived from both ambient noise and teleseismic earthquakes, together with P receiver function waveforms, we develop a 3-D Vs model for the crust and uppermost mantle beneath Central and West Antarctica to a depth of 200 km. Additionally, using this 3-D seismic model to constrain the crustal structure, we re-invert for the upper mantle thermal structure using the surface wave data within a thermodynamic framework and construct a 3-D thermal model for the Antarctic lithosphere. The final product, a high resolution thermal model together with associated uncertainty estimates from the Monte Carlo inversion, allows us to derive lithospheric thickness and surface heat flux maps for much of the continent. West Antarctica shows a much thinner lithosphere ( 50-90 km) than East Antarctica ( 130-230 km), with a sharp transition along the Transantarctic Mountains (TAM). A variety of geological features, including a slower/hotter but highly heterogeneous West Antarctica and a much faster/colder East Antarctic craton, are present in the 3-D seismic/thermal models. Notably, slow seismic velocities observed in the uppermost mantle beneath the southern TAM are interpreted as a signature of lithospheric foundering and replacement with hot asthenosphere. The high resolution image of these features from the 3-D models helps further investigation of the dynamic state of Antarctica's lithosphere and underlying asthenosphere

Upper mantle structure of central and West Antarctica from array analysis of Rayleigh wave phase velocities

NASA Astrophysics Data System (ADS)

Heeszel, David S.; Wiens, Douglas A.; Anandakrishnan, Sridhar; Aster, Richard C.; Dalziel, Ian W. D.; Huerta, Audrey D.; Nyblade, Andrew A.; Wilson, Terry J.; Winberry, J. Paul

2016-03-01

The seismic velocity structure of Antarctica is important, both as a constraint on the tectonic history of the continent and for understanding solid Earth interactions with the ice sheet. We use Rayleigh wave array analysis methods applied to teleseismic data from recent temporary broadband seismograph deployments to image the upper mantle structure of central and West Antarctica. Phase velocity maps are determined using a two-plane wave tomography method and are inverted for shear velocity using a Monte Carlo approach to estimate three-dimensional velocity structure. Results illuminate the structural dichotomy between the East Antarctic Craton and West Antarctica, with West Antarctica showing thinner crust and slower upper mantle velocity. West Antarctica is characterized by a 70-100 km thick lithosphere, underlain by a low-velocity zone to depths of at least 200 km. The slowest anomalies are beneath Ross Island and the Marie Byrd Land dome and are interpreted as upper mantle thermal anomalies possibly due to mantle plumes. The central Transantarctic Mountains are marked by an uppermost mantle slow-velocity anomaly, suggesting that the topography is thermally supported. The presence of thin, higher-velocity lithosphere to depths of about 70 km beneath the West Antarctic Rift System limits estimates of the regionally averaged heat flow to less than 90 mW/m2. The Ellsworth-Whitmore block is underlain by mantle with velocities that are intermediate between those of the West Antarctic Rift System and the East Antarctic Craton. We interpret this province as Precambrian continental lithosphere that has been altered by Phanerozoic tectonic and magmatic activity.

Tertiary Educators' Voices in Australia and South Africa: Experiencing and Engaging in African Music and Culture

ERIC Educational Resources Information Center

Joseph, Dawn

2015-01-01

Music tertiary educators can foster positive experiences that promote diversity, enhance intercultural and cross-cultural understanding through our teaching. Through findings of interview data of tertiary music educators' understandings of multicultural music practice at two South African universities and at an Australia university, I used…

Does Antarctic Glaciation Cause an Intensification of the Indo-Asian Monsoon Near the Eocene-Oligocene Transition?

NASA Astrophysics Data System (ADS)

Goldner, A. P.; Huber, M.; Caballero, R.

2011-12-01

High latitude ice volume changes has been suggested to have profound effects on the position of the Intertropical Convergence Zone (ITCZ). Here we simulate the atmospheric impacts that an Antarctica ice sheet of modern size has on the hydrologic cycle and atmospheric circulation using the community earth system model (CESM1.0) from the National Center for Atmospheric Research (NCAR) in Eocene simulations. Results show that the placement of an ice sheet in Antarctica in a late Eocene climate simulation cools the planet around ~2 Kelvin and causes a poleward displacement of the ITCZ in both hemispheres. Because the ITCZ is linked to the global monsoonal circulation. The shift results in an intensification of precipitation over prominent monsoon regions like Asia, Africa, and Australia. Aridification occurs in central Asia and western North America in agreement with many of the proxy records for the Eocene-Oligocene transition. The shift in atmospheric circulation and precipitation anomalies are robust in further sensitivity studies where we remove the ice sheet, but keep topography high over Antarctica and under different CO2 levels (560 and 1120 ppmv). We hypothesize that the height of the initial ice growth on Antarctica could be a significant factor in shifting the hydrologic cycle and matching proxy records over important regions like the Indo-Asian Monsoon region during the Eocene-Oligocene transition. These modeling results show that other factors besides declining atmospheric CO2, changes in orbital cycles, and the height of the Tibetan Plateau can have significant impacts on the tropical circulation and the global hydrologic cycle, especially the Indo-Asian Monsoon in past climate periods where significant changes in ice sheet growth occurred.

Intra-seasonal NDVI change projections in semi-arid Africa

USGS Publications Warehouse

Funk, Christopher C.; Brown, Molly E.

2006-01-01

Early warning systems (EWS) tend to focus on the identification of slow onset disasters such famine and epidemic disease. Since hazardous environmental conditions often precede disastrous outcomes by many months, effective monitoring via satellite and in situ observations can successfully guide mitigation activities. Accurate short term forecasts of NDVI could increase lead times, making early warning earlier. This paper presents a simple empirical model for making 1 to 4 month NDVI projections. These statistical projections are based on parameterized satellite rainfall estimates (RFE) and relative humidity demand (RHD). A quasi-global, 1 month ahead, 1° study demonstrates reasonable accuracies in many semi-arid regions. In Africa, a 0.1° cross-validated skill assessment quantifies the technique's applicability at 1 to 4 month forecast intervals. These results suggest that useful projections can be made over many semi-arid, food insecure regions of Africa, with plausible extensions to drought prone areas of Asia, Australia and South America.

Preliminary microphysical characterization of precipitation at ground over Antarctica coast

NASA Astrophysics Data System (ADS)

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

Annually-resolved temperature reconstructions of the past 2000 years from Dome-Fuji, East Antarctica

NASA Astrophysics Data System (ADS)

Motizuki, Yuko; Takahashi, Kazuya; Nakai, Yoichi; Motoyama, Hideaki

2016-04-01

We present annually-resolved temperature and SST reconstructions of the past 2000 years based on water (oxygen and deuterium) isotope measurement on a shallow ice core drilled in 2010 at Dome Fuji station, East Antarctica. These time series records will be an essential contribution to the PAGES 2k project from sparse data area in Antarctica. Dome Fuji station is located on a summit of Dronning Maud Land at an altitude of 3810 m a.s.l. (above sea level) (77o19'01'' S, 39o42'12'' E) in East Antarctica. The 10 m depth mean snow temperature at Dome Fuji is -57.3oC1). The inland area around Dome Fuji has been recognized to be especially unique: The snow and ice there contain much stratospheric information. The direct evidence for this comes from tritium contents originated from the nuclear bomb tests in the 1960s; the tritium fallout at the Dome Fuji site is outstandingly high among 16 snow pit samples widely collected over Antarctica2). To date the concerned Dome Fuji ice core, we applied volcanic signature matching to transfer the West Antarctic Ice Sheet (WAIS) Divide ice core chronology constructed by annual layer counting as used in the study by Sigl et al. (2014)3). In our presentation, we confine ourselves to discuss the oscillation periodicity that we observed in the oxygen isotope record in our data: The periods of approximately 10, 20, and 200 years were found. We will present the time series analyses for this in detail, and will discuss the origin of this periodicity. References: 1) Kameda, T., Motoyama, H., Fujita, S., and Takahashi, S.: "Past temporal and spatial variability of surface mass balance at Dome Fuji", East Antarctica, by the stake method from 1995 to 2006, J. Glaciol., 54, 107-116, 2008. 2) Fourre, E., Jean-Baptiste, P., Dapoigny, A., Baumier, D., Petit, J.-R., and Jouzel, J.: "Past and recent tritium levels in Arctic and Antarctic polar caps", Earth Planet. Sc. Lett., 245, 56-64, 2006. 3) Sigl, M., J. McConnell, M. Toohey, M. Curran, S. Das, R

Deglacial temperature history of West Antarctica

USGS Publications Warehouse

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.

2016-01-01

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∘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.

Deglacial temperature history of West Antarctica

PubMed Central

Clow, Gary D.; Steig, Eric J.; Buizert, Christo; Fudge, T. J.; Koutnik, Michelle; Waddington, Edwin D.; Alley, Richard B.

2016-01-01

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∘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. PMID:27911783

Illicit drug use and treatment in South Africa: a review.

PubMed

Peltzer, Karl; Ramlagan, Shandir; Johnson, Bruce D; Phaswana-Mafuya, Nancy

2010-11-01

This review synthesizes available epidemiological data on current drug use and substance user treatment admissions in South Africa since 1994, and how changes in the political, economic, and social structures within South Africa, both before and after Apartheid, has made the country more vulnerable to drug use. Based on national surveys, current use of cannabis ranged among adolescents from 2% to 9% and among adults it was 2%, cocaine/crack (0.3%), mandrax/sedatives (0.3%), club drugs/amphetamine-type stimulants (0.2%), opiates (0.1%), and hallucinogens (0.1%). The use of primary illicit substance at admission to South African drug user treatment centers was cannabis 16.9%, methamphetamine (tik) 12.8%, crack/cocaine 9.6%, cannabis and mandrax 3.4%, heroin/opiates 9.2%, and prescription and OTC drugs 2.6%. An increase in substance user treatment admissions has increased. While the prevalence of illicit drug use in South Africa is relatively low compared to the United States and Australia, prevention and intervention policies need to be designed to reduce these levels by targeting the more risky subpopulations identified from this review.

Young clades in an old family: major evolutionary transitions and diversification of the eucalypt-feeding pergid sawflies in Australia (Insecta, Hymenoptera, Pergidae).

PubMed

Schmidt, S; Walter, G H

2014-05-01

A calibrated phylogeny of the family Pergidae indicates that the major lineages within the family evolved during the fragmentation of the Gondwanan supercontinent. The split between the Pergidae and its sister group Argidae is estimated at about 153 Myr ago. No central dichotomous division between Australian and South American pergid sawflies was observed, showing that the major lineages within this group had already evolved by the time Australia had become completely isolated from Antarctica. The molecular dating analysis strongly indicates a co-radiation of Australian pergid sawflies with their Myrtaceae hosts and suggest that the two eucalypt-feeding clades, pergines and pterygophorines, colonised their eucalypt host plants independently during the Palaeocene, at the time when their hosts appear to have started radiating. The present analysis includes representatives of 13 of the 14 currently recognised subfamilies of Pergidae, almost all of which are supported by the molecular data presented here. Exceptions include the Euryinae (paraphyletic in respect to Perreyiinae), Acordulecerinae (paraphyletic to the Perginae), and the Australian Phylacteophaginae (placed within the Neotropical Acordulecerinae). The break-up of Gondwana and the timing of the subsequent climatic change in Australia, leading from vegetation adapted to a seasonal-wet conditions to the arid-adapted sclerophyll vegetation typical of Australia, suggest that the species-poor subfamilies occurring in rainforests represent remnants of more diverse groups that were decimated through loss of habitat or host species. Copyright © 2014 Elsevier Inc. All rights reserved.

How Important Is Research on Pollution Levels in Antarctica? Historical Approach, Difficulties and Current Trends.

PubMed

Szopińska, Małgorzata; Namieśnik, Jacek; Polkowska, Żaneta

Despite the fact that Antarctica is a continent notably free from large negative impact of human activities, literature data can be the basis for concluding that this is not an area free from anthropogenic pollutants. Pollutants, which are identified in various elements of the environment of Antarctica, are mostly connected with long-range atmospheric transport (LRAT) and deposition in this area. The study presents: a historical overview of research pertaining to the presence of pollutants in entire Antarctica; a description of the development of research on pollutants in various environmental samples conducted in this area since 1960; a detailed description of contemporary analytical research (2000-2014); information on concentration levels of a broad range of pollutants present in various elements of the environment. The data collected can provide grounds for concluding that pollutants present in this area can contribute to gradual degradation of Antarctic ecosystem.

Antarctica and global change research

NASA Astrophysics Data System (ADS)

Weller, Gunter; Lange, Manfred

1992-03-01

The Antarctic, including the continent and Southern Ocean with the subantarctic islands, is a critical area in the global change studies under the International Geosphere-Biosphere Program (IGBP) and the World Climate Research Program (WCRP). Major scientific problems include the impacts of climate warming, the ozone hole, and sea level changes. Large-scale interactions between the atmosphere, ice, ocean, and biota in the Antarctic affect the entire global system through feedbacks, biogeochemical cycles, deep-ocean circulation, atmospheric transport of heat, moisture, and pollutants, and changes in ice mass balances. Antarctica is also a rich repository of paleoenvironmental information in its ice sheet and its ocean and land sediments.

Wind profiler installed in Antarctica

NASA Astrophysics Data System (ADS)

Balsley, B. B.; Carey, J.; Woodman, R. F.; Sarango, M.; Urbina, J.; Rodriguez, R.; Ragaini, E.

A VHF (50 MHz) wind profiler was installed in Antarctica at the Peruvian Base “Machu Picchu” on King George Island from January 21 to 26. The wind profiler will provide a first look at atmospheric dynamics over the region.The profiler—the first of its kind in Antarctica—is a National Science Foundationsponsored cooperative project of the University of Colorado, the Geophysical Institute of Peru, the University of Piura (Peru), and the Peruvian Navy. This venture was also greatly facilitated by Peru's Comision Nacional de Asuntos Antartidos and Consejo Nacional de Ciencias y Tecnologia, with additional logis tics support provided by the Argentinean Navy and the Uruguayan Air Force.

The environmental impact of sewage and wastewater outfalls in Antarctica: An example from Davis station, East Antarctica.

PubMed

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 (<1.5 km), when sites were separated into groups of similar habitat types. Benthic community composition was also strongly related to habitat and 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

Earth Observations taken by the Expedition 16 Crew

NASA Image and Video Library

2008-01-15

ISS016-E-023196 (15 Jan. 2008) --- A portion of Mega-iceberg A53a in the South Atlantic Ocean is featured in this image photographed by an Expedition 16 crewmember on the International Space Station. At the time this image was taken in mid-January 2008, the entire iceberg measured close to 50 kilometers x 22 kilometers, about seven times the area of Manhattan Island. Icebergs of the Southern Atlantic Ocean contain rock material from Antarctica, eroded by the moving ice and also as wind-borne dust from deserts in Africa, South America and Australia. According to NASA scientists, the finest powdery rock material acts as nutrient for sea organisms. As icebergs melt, the surrounding seawater is enriched. The area of enrichment is significantly enlarged when a mega-iceberg disintegrates into many small pieces.

Earth Observations taken by the Expedition 16 Crew

NASA Image and Video Library

2008-01-15

ISS016-E-023197 (15 Jan. 2008) --- A portion of Mega-iceberg A53a in the South Atlantic Ocean is featured in this image photographed by an Expedition 16 crewmember on the International Space Station. At the time this image was taken in mid-January 2008, the entire iceberg measured close to 50 kilometers x 22 kilometers, about seven times the area of Manhattan Island. Icebergs of the Southern Atlantic Ocean contain rock material from Antarctica, eroded by the moving ice and also as wind-borne dust from deserts in Africa, South America and Australia. According to NASA scientists, the finest powdery rock material acts as nutrient for sea organisms. As icebergs melt, the surrounding seawater is enriched. The area of enrichment is significantly enlarged when a mega-iceberg disintegrates into many small pieces.

Earth Observations taken by the Expedition 16 Crew

NASA Image and Video Library

2008-01-15

ISS016-E-023198 (15 Jan. 2008) --- A portion of Mega-iceberg A53a in the South Atlantic Ocean is featured in this image photographed by an Expedition 16 crewmember on the International Space Station. At the time this image was taken in mid-January 2008, the entire iceberg measured close to 50 kilometers x 22 kilometers, about seven times the area of Manhattan Island. Icebergs of the Southern Atlantic Ocean contain rock material from Antarctica, eroded by the moving ice and also as wind-borne dust from deserts in Africa, South America and Australia. According to NASA scientists, the finest powdery rock material acts as nutrient for sea organisms. As icebergs melt, the surrounding seawater is enriched. The area of enrichment is significantly enlarged when a mega-iceberg disintegrates into many small pieces.

Continental magnetic anomaly constraints on continental reconstruction

NASA Technical Reports Server (NTRS)

Vonfrese, R. R. B.; Hinze, W. J.; Olivier, R.; Bentley, C. R.

1985-01-01

Crustal magnetic anomalies mapped by the MAGSAT satellite for North and South America, Europe, Africa, India, Australia and Antarctica and adjacent marine areas were adjusted to a common elevation of 400 km and differentially reduced to the radial pole of intensity 60,000 nT. These radially polarized anomalies are normalized for differential inclination, declination and intensity effects of the geomagnetic field, so that in principle they directly reflected the geometric and magnetic polarization attributes of sources which include regional petrologic variations of the crust and upper mantle, and crustal thickness and thermal perturbations. Continental anomalies demonstrate remarkably detailed correlation of regional magnetic sources across rifted margins when plotted on a reconstruction of Pangea. Accordingly, they suggest further fundamental constraints on the geologic evolution of the continents and their reconstructions.

Vocational Training and Lifelong Learning in Australia and Germany. Australia Centre Series.

ERIC Educational Resources Information Center

Burke, Gerald, Ed.; Reuling, Jochen, Ed.

This document contains 17 papers on vocational training and lifelong learning in Australia and Germany. The following papers are included: "Vocational Training and Lifelong Learning in Australia and Germany: Background" (Gerald Burke); "Vocational Training and Lifelong Learning in Australia: Observations and Conclusions from a…

Yeast activities involved in carbon and nitrogen cycles in Antarctica

USDA-ARS?s Scientific Manuscript database

Antarctica and sub Antarctic regions are characterized by extreme conditions for life such as low temperatures and nutrient availability, high solar radiation and dryness, however, microorganisms from the three domains of life have been found as common inhabitants of soils and waters from those zone...

Increased Ocean Access to Totten Glacier, East Antarctica

NASA Astrophysics Data System (ADS)

Blankenship, D. D.; Greenbaum, J. S.; Young, D. A.; Richter, T. G.; Roberts, J. L.; Aitken, A.; Legresy, B.; Warner, R. C.; van Ommen, T. D.; Siegert, M. J.

2015-12-01

The Totten Glacier is the largest ice sheet outlet in East Antarctica, draining 3.5 meters of eustatic sea level potential from the Aurora Subglacial Basin (ASB) into the Sabrina Coast. Recent work has shown that the ASB has drained and filled many times since largescale glaciation began including evidence that it collapsed during the Pliocene. Steady thinning rates observed near Totten Glacier's grounding line since the beginning of the satellite altimetry record are the largest in East Antarctica and the nature of the thinning suggests that it is driven by enhanced basal melting due to ocean processes. Warm Modified Circumpolar Deep Water (MCDW), which has been linked to glacier retreat in West Antarctica, has been observed in summer and winter on the Sabrina Coast continental shelf in the 400-500 m depth range. Using airborne geophysical data acquired over multiple years we delineate seafloor valleys connecting the inner continental shelf to the cavity beneath Totten Glacier that cut through a large sill centered along the ice shelf calving front. The sill shallows to depths of about 300 mbsl and was likely a grounding line pinning point during Holocene retreat, however, the two largest seafloor valleys are deeper than the observed range of thermocline depths. The deeper of the two valleys, a 4 km-wide trough, connects to the ice shelf cavity through an area of the coastline that was previously believed to be grounded but that our analysis demonstrates is floating, revealing a second, deeper entryway to ice shelf cavity. The previous coastline was charted using satellite-based mapping techniques that infer subglacial properties based on surface expression and behavior; the new geophysical analysis techniques we use enable inferences of subglacial characteristics using direct observations of the ice-water interface. The results indicate that Totten Glacier and, by extension, the Aurora Subglacial Basin are vulnerable to MCDW that has been observed on the nearby

Weathering process in Sør Rondane Mountains, East Antarctica

NASA Astrophysics Data System (ADS)

Kanamaru, T.; Suganuma, Y.; Oiwane, H.; Miura, M.; Okuno, J.; Hayakawa, H.

2016-12-01

Weathering process under the hyper-arid and hypothermal environment is a key to understand the geomorphogic process and landscape evolution in Antarctica and on Mars. A nunber of studies have focused on weathering process of basaltic rocks in Antarctica, however, the nature of the weathering process of plutonic type rock, a common rock type on the Earth, have been less focused and remain unclear. Here, we report the physical/chemical weathering process of the granitic rocks obtained from Dronning Maud Land in East Antarctica based on a multiplicity of petrological approaches. Loss on Ignition (LOI) and major element composition of the crust and core of the rock samples indicate that chemical weathering process in this area seems to be very limited. The microscopic observations and laser-Raman micro spectroscopy for thin sections from the crust and core indicate that goethite grains are formed mainly in the vein around the crust, which is consistent with the higher Fe3+/Fe2+ contrast from the core to crust. A negative correlation between the rock hardness and color strength index (CSI) values also indicate that crust of rock samples tend to less hard than core due to cracking of the rock samples and following goethite formation. On the other hand, EPMA analysis indicates that original Fe-Ti oxide grains in the core of rock samples are damaged by weathering, and altered to hematite, and to non-stoichiometric Fe-Ti compound associated with ilmenite grans in case of the higher relative height samples. These reveal that the weathering process of the plutonic rocks under the hyper-cold and hypothermal environment are mainly controlled by oxidation, including iron hydroxide formation in the veins formed by mechanical distraction, and Fe-Ti oxide alteration in rock interior.

Soils of the Galindez Island, Argentine archipelago, Western Antarctica

NASA Astrophysics Data System (ADS)

Abakumov, Evgeny; Parnikoza, Ivan

2015-04-01

Antarctic Peninsula is a part of Antarctica which is characterized by increased soil diversity, caused by specific of parent materials and diversity of non-vascular and vascular plants. Soils of Galindez Island have been investigated during the 18-th Ukranian Antarctic Expedition 2013/14. This Island situated in Argentine archipelago (coastal part of Antarctic Peninsula). Soils of Galindez Island presented by following types: Leptosols, Lithosols, Histic Lithosols and Leptosols and some Gleyic soils, located in lowlands and coastal parts. An average solum profile thickness is 3-19 cm which result from the small depth of debris's, underplayed by massive crystallic rocks. The permafrost layer is located within the massive rock, but not in coarse friable parent material. The soils with bird influence are widely spread both in coastal and central part of Island. In the coastal parts we can find typical Ornithosols in the penguin rockeries areas. The main aim of our investigation was characterization of soils formed under vegetation, exactly under Deschampsia antarctica Desv. localities. Argentine Islands is the central part of D. antarctica spreading area in region of Antarctic peninsula. Probably, these islands colonized by hairgrass mainly due to ornitogenic activity. So, coastal population appearance related with Larus dominicanus nest areas and feeding activity. Thus, we found typical post ornithogenic soils here. This kind of soils we also observed in population of hairgrass of Galindez mainland where it was connected with the other Antarctic bird - Catharacta maccormicki activity. Thus, the soil diversity and soil geochemistry of the Galindez Island are closely related to the activity of birds. The spatial pattern of soils, their chemistry and organic matter quality is discussed in relation with distribution of bird nesting and feeding activity.

Application of a Terrestrial LIDAR System for Elevation Mapping in Terra Nova Bay, Antarctica.

PubMed

Cho, Hyoungsig; Hong, Seunghwan; Kim, Sangmin; Park, Hyokeun; Park, Ilsuk; Sohn, Hong-Gyoo

2015-09-16

A terrestrial Light Detection and Ranging (LIDAR) system has high productivity and accuracy for topographic mapping, but the harsh conditions of Antarctica make LIDAR operation difficult. Low temperatures cause malfunctioning of the LIDAR system, and unpredictable strong winds can deteriorate data quality by irregularly shaking co-registration targets. For stable and efficient LIDAR operation in Antarctica, this study proposes and demonstrates the following practical solutions: (1) a lagging cover with a heating pack to maintain the temperature of the terrestrial LIDAR system; (2) co-registration using square planar targets and two-step point-merging methods based on extracted feature points and the Iterative Closest Point (ICP) algorithm; and (3) a georeferencing module consisting of an artificial target and a Global Navigation Satellite System (GNSS) receiver. The solutions were used to produce a topographic map for construction of the Jang Bogo Research Station in Terra Nova Bay, Antarctica. Co-registration and georeferencing precision reached 5 and 45 mm, respectively, and the accuracy of the Digital Elevation Model (DEM) generated from the LIDAR scanning data was ±27.7 cm.

Methods for Combination of GRACE Gravimetry and ICESat Altimetry over Antarctica on Monthly Timescales

NASA Astrophysics Data System (ADS)

Hardy, R. A.; Nerem, R. S.; Wiese, D. N.

2017-12-01

Gravity and surface elevation change data altimetry provide different perspectives on mass variability in Antarctica. In anticipation of the concurrent operation of the successors of GRACE and ICESat, GRACE Follow-On and ICESat-2, we approach the problem of combining these data for enhanced spatial resolution and disaggregation of Antarctica's major mass transport processes. Using elevation changes gathered from over 500 million overlapping ICESat laser shot pairs between 2003 and 2009, we construct gridded models of Antarctic elevation change for each ICESat operational period. Comparing these elevation grids with temporally registered JPL RL05M mascon solutions, we exploit the relationship between surface mass flux and elevation change to inform estimates of effective surface density. These density estimates enable solutions for glacial isostatic adjustment and monthly estimates of surface mass change. These are used alongside spatial statistics from both the data and models of surface mass balance to produce enhanced estimates of Antarctic mass balance. We validate our solutions by modeling the effects of elastic loading and GIA from these solutions on the vertical motion of Antarctica's GNSS sites.

The Age of Rift-Related Basalts in East Antarctica

NASA Astrophysics Data System (ADS)

Leitchenkov, G. L.; Belyatsky, B. V.; Kaminsky, V. D.

2018-01-01

The Lambert Rift, which is a large intracontinental rift zone in East Antarctica, developed over a long period of geological time, beginning from the Late Paleozoic, and its evolution was accompanied by magmatic activity. The latest manifestation of magmatism is eruption of alkaline olivine-leucite basalts on the western side of the Lambert Rift; Rb-Sr dating referred its time to the Middle Eocene, although its genesis remained vague. In order to solve this problem, we found geochronometer minerals in basaltic samples and 68 apatite grains appeared to be suitable for analysis. Their ages and ages of host basalts, determined by the U-Pb local method on the SIMS SHRIMP-II, were significantly different (323 ± 31 Ma) from those assumed earlier. This age corresponds to the earliest stage of crustal extension in East Antarctica and to most of Gondwana. The new data crucially change the ideas about the evolution of Lambert Rift and demonstrate the ambiguity of K-Ar dates of the alkali effusive formed under long-term rifting.

Upper mantle seismic structure beneath central East Antarctica from body wave tomography: Implications for the origin of the Gamburtsev Subglacial Mountains

NASA Astrophysics Data System (ADS)

Lloyd, Andrew J.; Nyblade, Andrew A.; Wiens, Douglas A.; Hansen, Samantha E.; Kanao, Masaki; Shore, Patrick J.; Zhao, Dapeng

2013-04-01

The Gamburtsev Subglacial Mountains (GSM), located near the center of East Antarctica, are the highest feature within the East Antarctic highlands and have been investigated seismically for the first time during the 2007/2008 International Polar Year by the Gamburtsev Mountains Seismic Experiment. Using data from a network of 26 broadband seismic stations and body wave tomography, the P and S wave velocity structure of the upper mantle beneath the GSM and adjacent regions has been examined. Tomographic images produced from teleseismic P and S phases reveal several large-scale, small amplitude anomalies (δVp = 1.0%, δVs = 2.0%) in the upper 250 km of the mantle. The lateral distributions of these large-scale anomalies are similar in both the P and S wave velocity models and resolution tests show that they are well resolved. Velocity anomalies indicate slower, thinner lithosphere beneath the likely Meso- or Neoproterozoic Polar Subglacial Basin and faster, thicker lithosphere beneath the likely Archean/Paleoproterozoic East Antarctic highlands. Within the region of faster, thicker lithosphere, a lower amplitude (δVp = 0.5%, δVs = 1.0%) slow to fast velocity pattern is observed beneath the western flank of the GSM, suggesting a suture between two lithospheric blocks possibly of similar age. These findings point to a Precambrian origin for the high topography of the GSM, corroborating other studies invoking a long-lived highland landscape in central East Antarctica, as opposed to uplift caused by Permian/Cretaceous rifting or Cenozoic magmatism. The longevity of the GSM makes them geologically unusual; however, plausible analogs exist, such as the 550 Ma Petermann Ranges in central Australia. Additional uplift may have occurred by the reactivation of pre-existing faults, for example, during the Carboniferous-Permian collision of Gondwana and Laurussia.

An interdecadal climate dipole between Northeast Asia and Antarctica over the past five centuries

NASA Astrophysics Data System (ADS)

Fang, Keyan; Chen, Deliang; Guo, Zhengtang; Zhao, Yan; Frank, David; He, Maosheng; Zhou, Feifei; Shi, Feng; Seppä, Heikki; Zhang, Peng; Neukom, Raphael

2018-03-01

Climate models emphasize the need to investigate inter-hemispheric climatic interactions. However, these models often underestimate the inter-hemispheric differences in climate change. With the wide application of reanalysis data since 1948, we identified a dipole pattern between the geopotential heights (GPHs) in Northeast Asia and Antarctica on the interdecadal scale in boreal summer. This Northeast Asia/Antarctica (NAA) dipole pattern is not conspicuous on the interannual scale, probably in that the interannual inter-hemispheric climate interaction is masked by strong interannual signals in the tropics associated with the El Niño-Southern Oscillation (ENSO). Unfortunately, the instrumental records are not sufficiently long-lasting to detect the interdecadal variability of the NAA. We thus reconstructed GPHs since 1565, making using the proxy records mostly from tree rings in Northeast Asia and ice cores from Antarctica. The strength of the NAA is time-varying and it is most conspicuous in the eighteenth century and after the late twentieth century. The strength of the NAA matches well with the variations of the solar radiation and tends to increase in along with its enhancement. In boreal summer, enhanced heating associated with high solar radiation in the Northern Hemisphere drives more air masses from the South to the North. This inter-hemispheric interaction is particularly strong in East Asia as a result of the Asian summer monsoon. Northeast Asia and Antarctica appear to be the key regions responsible for inter-hemispheric interactions on the interdecadal scale in boreal summer since they are respectively located at the front and the end of this inter-hemispheric trajectory.

Regional geology mapping using satellite-based remote sensing approach in Northern Victoria Land, Antarctica

NASA Astrophysics Data System (ADS)

Pour, Amin Beiranvand; Park, Yongcheol; Park, Tae-Yoon S.; Hong, Jong Kuk; Hashim, Mazlan; Woo, Jusun; Ayoobi, Iman

2018-06-01

Satellite remote sensing imagery is especially useful for geological investigations in Antarctica because of its remoteness and extreme environmental conditions that constrain direct geological survey. The highest percentage of exposed rocks and soils in Antarctica occurs in Northern Victoria Land (NVL). Exposed Rocks in NVL were part of the paleo-Pacific margin of East Gondwana during the Paleozoic time. This investigation provides a satellite-based remote sensing approach for regional geological mapping in the NVL, Antarctica. Landsat-8 and the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) datasets were used to extract lithological-structural and mineralogical information. Several spectral-band ratio indices were developed using Landsat-8 and ASTER bands and proposed for Antarctic environments to map spectral signatures of snow/ice, iron oxide/hydroxide minerals, Al-OH-bearing and Fe, Mg-OH and CO3 mineral zones, and quartz-rich felsic and mafic-to-ultramafic lithological units. The spectral-band ratio indices were tested and implemented to Level 1 terrain-corrected (L1T) products of Landsat-8 and ASTER datasets covering the NVL. The surface distribution of the mineral assemblages was mapped using the spectral-band ratio indices and verified by geological expeditions and laboratory analysis. Resultant image maps derived from spectral-band ratio indices that developed in this study are fairly accurate and correspond well with existing geological maps of the NVL. The spectral-band ratio indices developed in this study are especially useful for geological investigations in inaccessible locations and poorly exposed lithological units in Antarctica environments.

Nurses' supervisors, learning options and organisational commitment: Australia, Brazil and England.

PubMed

Brunetto, Yvonne; Shacklock, Kate; Teo, Stephen; Farr-Wharton, Rod; Nelson, Silvia

2015-11-01

To examine the relationships between leader-member exchange (LMX), workplace learning options (teamwork, training and development), empowerment and organisational commitment, for nurses in Australia, England and Brazil. The supervisor-employee relationship is fundamental to management theory and practice within the work context of Organisation for Economic Cooperation and Development (OECD) countries. Survey-based, self-report data were collected from 1350 nurses in 23 acute-care hospitals during 2011. Significant relationships were found between key Social Exchange Theory antecedents (LMX and teamwork) and outcomes (organisational commitment) for nurses in Australia and England, but not in Brazil. As expected, the path between teamwork and organisational commitment was significant in the three countries. The findings affirm the importance of LMX as a management tool affecting employee outcomes in OECD countries. In contrast, LMX cannot be assumed to play an important role within a context that operates a dual employment structure coupled with a culture accepting of 'Jeitinho' workplace relationships. Informal workplace relationships - 'Jeitinho' (similar to the Chinese 'guanxi') may be worthy of examination within BRICS (Brazil, Russia, India, China and South Africa) countries such as Brazil. © 2014 John Wiley & Sons Ltd.

Abrupt climate warming in East Antarctica during the early Holocene

NASA Astrophysics Data System (ADS)

Cremer, Holger; Heiri, Oliver; Wagner, Bernd; Wagner-Cremer, Friederike

2007-08-01

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 values around 8500 y ago reflecting relatively warm and ice-free conditions that led to well-ventilated conditions in the lake and considerable sedimentation of both autochthonous and allochthonous organic matter on the lake bottom. This abrupt warming event occurred concurrently with reported warm climatic conditions in the Southern Ocean while the climate in central East Antarctic remained cold. The comparison of the spatial and temporal variability of warm climatic periods documented in various terrestrial, marine, and glacial archives from East Antarctica elucidates the uniqueness of the centennial-scale warming event in the Amery Oasis. We also discuss a possible correlation of the Amery warming event with the abrupt climatic deterioration around 8200 cal BP on the Northern Hemisphere.

Lithospheric Shear Stresses Over And Around Africa

NASA Astrophysics Data System (ADS)

Greff-Lefftz, M.; Jean, B.; Vicente De Gouveia, S.

2017-12-01

We use a simple model for mantle dynamics combining contributions of subducted lithosphere, domes at the bottom of the mantle and upwelling plumes. A dominant feature of plate tectonics is the quasi permanence of a girdle of subductions around the Pacific ocean (or its ancestor), which creates large-wavelength positive topography anomaly within the ring they form. The superimposition of the resultant extension with the one induced by the dome leads to a permanent extensional regime over Africa and the future Indian ocean which creates faults with azimuth directions depending on the direction of the most active part of the ring of subductions. We thus obtain fractures with NW-SE azimuth during the period 275-165 Ma parallel to the strike of the subduction zone of the West South American active margin, which appears to be very active during this period. Between 155-95 Ma, subduction became more active along the Eastern Australian coast involving a change in the direction of the faults toward an E-W direction, in agreement with the observed fault systems between Africa and India, Antartica and Australia. During the Mesozoic and the Cenozoic, we correlate the permanent extensional regime over Africa and Indian ocean with the observed rift systems.Finally we emphasize the role of three primary hotspots as local additional contributors to the stress field imposed by our proposed subduction-doming system, which help in the opening of Indian and South Atlantic oceans.

Transcriptome of the Antarctic brooding gastropod mollusc Margarella antarctica.

PubMed

Clark, Melody S; Thorne, Michael A S

2015-12-01

454 RNA-Seq transcriptome data were generated from foot tissue of the Antarctic brooding gastropod mollusc Margarella antarctica. A total of 6195 contigs were assembled de novo, providing a useful resource for researchers with an interest in Antarctic marine species, phylogenetics and mollusc biology, especially shell production. Copyright © 2015 Elsevier B.V. All rights reserved.

Analysis of ICESat Data Using Kalman Filter and Kriging to Study Height Changes in East Antarctica

NASA Technical Reports Server (NTRS)

Herring, Thomas A.

2005-01-01

We analyze ICESat derived heights collected between Feb. 03-Nov. 04 using a kriging/Kalman filtering approach to investigate height changes in East Antarctica. The model's parameters are height change to an a priori static digital height model, seasonal signal expressed as an amplitude Beta and phase Theta, and height-change rate dh/dt for each (100 km)(exp 2) block. From the Kalman filter results, dh/dt has a mean of -0.06 m/yr in the flat interior of East Antarctica. Spatially correlated pointing errors in the current data releases give uncertainties in the range 0.06 m/yr, making height change detection unreliable at this time. Our test shows that when using all available data with pointing knowledge equivalent to that of Laser 2a, height change detection with an accuracy level 0.02 m/yr can be achieved over flat terrains in East Antarctica.

Recent geophysical and geological research in Antarctica related to the assessment of petroleum resources and potential environmental hazards to their development

USGS Publications Warehouse

Behrendt, John C.; Splettstoesser, John F.; Dreschoff, Gisela A. M.

1990-01-01

During the 6-year negotiation of and adoption of the Convention on the Regulation of Antarctic Mineral Resources Activities on June 2, 1988, various countries have increased their attention to the possibility of exploitation of Antarctica's petroleum resources, which are covered by this treaty. However, there are no known petroleum resources in Antarctica, and scientific information is lacking to adequately assess any undiscovered resources or the possible environmental hazards to their development. Scientific research carried out in Antarctica since the International Geophysical Year (1957-1958) has provided a great deal of information on the geological framework of this ice-covered continent and its margin and has found general indications of the types of hazards that must be considered. Antarctica covers a vast area, and likely supergiant oil fields of the type to be exploited would be tiny (e.g., a few tens of kilometers across) in comparison. Any petroleum resources located in Antarctica will be found by applying the knowledge, techniques, and experience gained developing oil fields in other parts of the world and would, therefore, be other examples of general cases; in contrast, the Antarctic environment and its associated hazards must be considered unique.

Does temperature structure phytoplankton community composition in the Ross Sea, Antarctica?

EPA Science Inventory

The Ross Sea polynya experiences one of the largest phytoplankton blooms in the Southern Ocean. Energy flow potential within the Ross Sea food web is primarily set by diatoms and prymnesiophytes, the latter dominated by Phaeocystis antarctica. We investigated physical, chemical,...

2001 Mars Odyssey Images Earth (Visible and Infrared)

NASA Technical Reports Server (NTRS)

2001-01-01

2001 Mars Odyssey's Thermal Emission Imaging System (THEMIS) acquired these images of the Earth using its visible and infrared cameras as it left the Earth. The visible image shows the thin crescent viewed from Odyssey's perspective. The infrared image was acquired at exactly the same time, but shows the entire Earth using the infrared's 'night-vision' capability. Invisible light the instrument sees only reflected sunlight and therefore sees nothing on the night side of the planet. In infrared light the camera observes the light emitted by all regions of the Earth. The coldest ground temperatures seen correspond to the nighttime regions of Antarctica; the warmest temperatures occur in Australia. The low temperature in Antarctica is minus 50 degrees Celsius (minus 58 degrees Fahrenheit); the high temperature at night in Australia 9 degrees Celsius(48.2 degrees Fahrenheit). These temperatures agree remarkably well with observed temperatures of minus 63 degrees Celsius at Vostok Station in Antarctica, and 10 degrees Celsius in Australia. The images were taken at a distance of 3,563,735 kilometers (more than 2 million miles) on April 19,2001 as the Odyssey spacecraft left Earth.

Australia, Shaded Relief and Colored Height

NASA Technical Reports Server (NTRS)

2004-01-01

Australia is the world's smallest, flattest, and (after Antarctica) driest continent, but at 7.7 million square kilometers (3.0 million square miles) it is also the sixth largest country. Its low average elevation (300 meters, or less than 1000 feet) is caused by its position near the center of a tectonic plate, where there are no volcanic or other geologic forces of the type that raise the topography of other continents. In fact Australia is the only continent without any current volcanic activity at all - the last eruption took place 1400 years ago at Mt. Gambier.

The Australian continent is also one of the oldest land masses, with some of its erosion-exposed bedrock age dated at more than 3 billion years. More than one-fifth of the land area is desert, with more than two-thirds being classified as arid or semi-arid and unsuitable for settlement. The coldest regions are in the highlands and tablelands of Tasmania and the Australian Alps at the southeastern corner of the continent, location of Australia's highest point, Mt. Kosciusko (2228 meters, or 7310 feet.)

Prominent features of Australia include the Lake Eyre basin, the darker green region visible in the center-right. At 16 meters (52 feet) below sea level this depression is one of the largest inland drainage systems in the world, covering more than 1.3 million square kilometers (500,000 square miles). The mountain range near the east coast is called the Great Dividing Range, forming a watershed between east and west flowing rivers. Erosion has created deep valleys, gorges and waterfalls in this range where rivers tumble over escarpments on their way to the sea.

The crescent shaped uniform green region in the south, just left of center, is the Nullarbor Plain, a low-lying limestone plateau which is so flat that the Trans-Australian Railway runs through it in a straight line for more than 483 kilometers (300 miles).

Two visualization methods were combined to produce this image

Low-level precipitation sublimation on the coasts of East Antarctica

NASA Astrophysics Data System (ADS)

Grazioli, Jacopo; Genthon, Christophe; Madeleine, Jean-Baptiste; Lemonnier, Florentin; Gallée, Hubert; Krinner, Gerhard; Berne, Alexis

2017-04-01

The weather of East Antarctica is affected by the peculiar morphology of this large continent and by its isolation from the surroundings. The high-elevation interior of the continent, very dry in absolute terms, originates winds that can reach the coastal areas with very high speed and persistence in time. The absence of topographic barriers and the near-ground temperature inversion allow these density-driven air movements to fall from the continent towards the coasts without excessive interaction and mixing with the atmosphere aloft. Thus, the air remains dry in absolute terms, and very dry in relative terms because of the higher temperatures near the coast and the adiabatic warming due to the descent. The coasts of Antarctica are less isolated and more exposed to incoming moist air masses than the rest of the continent, and precipitation in the form of snowfall more frequently occurs. Through its descent, however, snowfall encounters the layer of dry air coming from the continent and the deficit in humidity can lead to the partial or complete sublimation of the precipitating flux. This phenomenon is named here LPS (Low-level Precipitation Sublimation) and it has been observed by means of ground-based remote sensing instruments (weather radars) and atmospheric radio-sounding balloons records in the framework of the APRES3 campaign (Antarctic Precipitation: REmote Sensing from Surface and Space) in the coastal base of Dumont d' Urville (Terre Adélie), and then examined at the continental scale thanks to numerical weather models. LPS occurs over most of the coastal locations, where the total sublimated snowfall can be a significant percentage of the total snowfall. For example, in Dumont d' Urville the total yearly snowfall at 341 m height is less than 80% of the snowfall at 941 m height (the height of maximum yearly accumulation), and at shorter time scales complete sublimation (i.e. virga) often occurs. At the scale of individual precipitation events, LPS is

Basal melt rates of Filchner Ice Shelf, Antarctica

NASA Astrophysics Data System (ADS)

Humbert, A.; Nicholls, K. W.; Corr, H. F. J.; Steinhage, D.; Stewart, C.; Zeising, O.

2017-12-01

Thinning of ice shelves around Antarctica has been found to be partly driven by an increase in basal melt as a result of warmer waters entering the sub-ice shelf cavity. In-situ observations of basal melt rate are, however, sparse. A new robust and efficient phase sensitive radio echo sounder (pRES) allows to measure change in ice thickness and vertical strain at high accuracy, so that the contribution of basal melt to the change in thickness can be estimated. As modeling studies suggest that the cavity beneath Filchner Ice Shelf, Antarctica, might be prone to intrusion of warm water pulses within this century, we wished to derive a baseline dataset and an understanding of its present day spatial variability. Here we present results from pRES measurements over two field seasons, 2015/16-16/17, comprising 86 datasets over the southern Filchner Ice Shelf, covering an area of about 6500km2. The maximum melt rate is only slightly more than 1m/a, but the spatial distribution exhibits a complex pattern. For the purpose of testing variability of basal melt rates on small spatial scales, we performed 26 measurements over distances of about 1km, and show that the melt rates do not vary by more than 0.25m/a.

Design of a seismo-acoustic station for Antarctica.

PubMed

Contrafatto, Danilo; Fasone, Rosario; Ferro, Angelo; Larocca, Graziano; Laudani, Giuseppe; Rapisarda, Salvatore; Scuderi, Luciano; Zuccarello, Luciano; Privitera, Eugenio; Cannata, Andrea

2018-04-01

In recent years, seismological studies in Antarctica have contributed plenty of new knowledge in many fields of earth science. Moreover, acoustic investigations are now also considered a powerful tool that provides insights for many different objectives, such as analyses of regional climate-related changes and studies of volcanic degassing and explosive activities. However, installation and maintenance of scientific instrumentation in Antarctica can be really challenging. Indeed, the instruments have to face the most extreme climate on the planet. They must be tolerant of very low temperatures and robust enough to survive strong winds. Moreover, one of the most critical tasks is powering a remote system year-round at polar latitudes. In this work, we present a novel seismo-acoustic station designed to work reliably in polar regions. To enable year-round seismo-acoustic data collection in such a remote, extreme environment, a hybrid powering system is used, integrating solar panels, a wind generator, and batteries. A power management system was specifically developed to either charge the battery bank or divert energy surplus to warm the enclosure or release the excess energy to the outside environment. Finally, due to the prohibitive environmental conditions at most Antarctic installation sites, the station was designed to be deployed quickly.

Design of a seismo-acoustic station for Antarctica

NASA Astrophysics Data System (ADS)

Contrafatto, Danilo; Fasone, Rosario; Ferro, Angelo; Larocca, Graziano; Laudani, Giuseppe; Rapisarda, Salvatore; Scuderi, Luciano; Zuccarello, Luciano; Privitera, Eugenio; Cannata, Andrea

2018-04-01

In recent years, seismological studies in Antarctica have contributed plenty of new knowledge in many fields of earth science. Moreover, acoustic investigations are now also considered a powerful tool that provides insights for many different objectives, such as analyses of regional climate-related changes and studies of volcanic degassing and explosive activities. However, installation and maintenance of scientific instrumentation in Antarctica can be really challenging. Indeed, the instruments have to face the most extreme climate on the planet. They must be tolerant of very low temperatures and robust enough to survive strong winds. Moreover, one of the most critical tasks is powering a remote system year-round at polar latitudes. In this work, we present a novel seismo-acoustic station designed to work reliably in polar regions. To enable year-round seismo-acoustic data collection in such a remote, extreme environment, a hybrid powering system is used, integrating solar panels, a wind generator, and batteries. A power management system was specifically developed to either charge the battery bank or divert energy surplus to warm the enclosure or release the excess energy to the outside environment. Finally, due to the prohibitive environmental conditions at most Antarctic installation sites, the station was designed to be deployed quickly.

Ultimate Eocene (Priabonian) Chondrichthyans (Holocephali, Elasmobranchii) of Antarctica

PubMed Central

Kriwet, Jürgen; Engelbrecht, Andrea; Mörs, Thomas; Reguero, Marcelo; Pfaff, Cathrin

2017-01-01

The Eocene La Meseta Formation on Seymour Island, Antarctic Peninsula, is known for its remarkable wealth of fossil remains of chondrichthyans and teleosts. Chondrichthyans seemingly were dominant elements in the Antarctic Paleogene fish fauna, but decreased in abundance from middle to late Eocene, during which time remains of bony fishes increase. This decline of chondrichthyans at the end of the Eocene generally is related to sudden cooling of seawater, reduction in shelf area, and increasing shelf depth due to the onset of the Antarctic thermal isolation. The last chondrichthyan records known so far include a chimeroid tooth plate from TELM 6 (Lutetian) and a single pristiophorid rostral spine from TELM 7 (Priabonian). Here, we present new chondrichthyan records of Squalus, Squatina, Pristiophorus, Striatolamia, Palaeohypotodus, Carcharocles, and Ischyodus from the upper parts of TELM 7 (Priabonian), including the first record of Carcharocles sokolovi from Antarctica. This assemblage suggests that chondrichthyans persisted much longer in Antarctic waters despite rather cool sea surface temperatures of approximately 5°C. The final disappearance of chondrichthyans at the Eocene–Oligocene boundary concurs with abrupt ice sheet formation in Antarctica. Diversity patterns of chondrichthyans throughout the La Meseta Formation appear to be related to climatic conditions rather than plate tectonics. PMID:28298806

Ultimate Eocene (Priabonian) Chondrichthyans (Holocephali, Elasmobranchii) of Antarctica.

PubMed

Kriwet, Jürgen; Engelbrecht, Andrea; Mörs, Thomas; Reguero, Marcelo; Pfaff, Cathrin

2016-01-01

The Eocene La Meseta Formation on Seymour Island, Antarctic Peninsula, is known for its remarkable wealth of fossil remains of chondrichthyans and teleosts. Chondrichthyans seemingly were dominant elements in the Antarctic Paleogene fish fauna, but decreased in abundance from middle to late Eocene, during which time remains of bony fishes increase. This decline of chondrichthyans at the end of the Eocene generally is related to sudden cooling of seawater, reduction in shelf area, and increasing shelf depth due to the onset of the Antarctic thermal isolation. The last chondrichthyan records known so far include a chimeroid tooth plate from TELM 6 (Lutetian) and a single pristiophorid rostral spine from TELM 7 (Priabonian). Here, we present new chondrichthyan records of Squalus , Squatina , Pristiophorus , Striatolamia , Palaeohypotodus , Carcharocles , and Ischyodus from the upper parts of TELM 7 (Priabonian), including the first record of Carcharocles sokolovi from Antarctica. This assemblage suggests that chondrichthyans persisted much longer in Antarctic waters despite rather cool sea surface temperatures of approximately 5°C. The final disappearance of chondrichthyans at the Eocene-Oligocene boundary concurs with abrupt ice sheet formation in Antarctica. Diversity patterns of chondrichthyans throughout the La Meseta Formation appear to be related to climatic conditions rather than plate tectonics.

Pattern of passenger injury and illness on expedition cruise ships to Antarctica.

PubMed

Schutz, Lusana; Zak, Dan; Holmes, James F

2014-01-01

Expedition ships to Antarctica travel to remote areas with limited medical support. This study determines the rate and patterns of passenger illness and injuries among those traveling on expedition ships to Antarctica. We hypothesize that severe medical conditions are encountered that require physicians serving on these ships to be skilled enough to care for critically ill or injured patients. We performed a retrospective analysis of the medical records of all passengers who were provided medical care on 26 Antarctica voyages from October 2010 to March 2011 (four different expedition ships). A structured system was used to categorize the diagnoses from each patient encounter. The pattern of traumatic injuries was noted, including location of occurrence. Treatments rendered including patient evacuations were documented. The population is described with incidence rates. A total of 2,366 passengers traveled on 26 trips, for a total of 34,501 person-days. In all, 680 physician visits were done, including 150 consultations for motion sickness preventive care, leaving 530 visits (15.4 visits per 1,000 person-days) for active medical care. Median age was 50 (range 10-90) years and 51% were females. Incidence rates per 1,000 person-days for the most common processes include motion sickness (4.2), infections (3.5), and injury (2.0). Injuries were more likely to occur on the ship (66%, 95% CI: 54-77%) compared to off the ship (34%, 95% CI: 23-46%). Four subjects (0.12/1,000 person-days) were evacuated (three due to traumatic conditions and one due to medical complications) and one person died (medical complication). Passengers on expedition ships to Antarctica may experience significant illness and injury. Ship physicians should be aware of the patterns of injuries and illnesses that occur on expedition ships and should have appropriate training to treat various medical and traumatic conditions including life-threatening illnesses. © 2014 International Society of Travel

Climate Proxies: An Inquiry-Based Approach to Discovering Climate Change on Antarctica

NASA Astrophysics Data System (ADS)

Wishart, D. N.

2016-12-01

An attractive way to advance climate literacy in higher education is to emphasize its relevance while teaching climate change across the curriculum to science majors and non-science majors. An inquiry-based pedagogical approach was used to engage five groups of students on a "Polar Discovery Project" aimed at interpreting the paleoclimate history of ice cores from Antarctica. Learning objectives and student learning outcomes were clearly defined. Students were assigned several exercises ranging from examination of Antarctic topography to the application of physical and chemical measurements as proxies for climate change. Required materials included base and topographic maps of Antarctica; graph sheets for construction of topographic cross-sectional profiles from profile lines of the Western Antarctica Ice Sheet (WAIS) Divide and East Antarctica; high-resolution photographs of Antarctic ice cores; stratigraphic columns of ice cores; borehole and glaciochemical data (i.e. anions, actions, δ18O, δD etc.); and isotope data on greenhouse gases (CH4, O2, N2) extracted from gas bubbles in ice cores. The methodology was to engage students in (2) construction of topographic profiles; (2) suggest directions for ice flow based on simple physics; (3) formulate decisions on suitable locations for drilling ice cores; (4) visual ice stratigraphy including ice layer counting; (5) observation of any insoluble particles (i.e. meteoritic and volcanic material); (6) analysis of borehole temperature profiles; and (7) the interpretation of several datasets to derive a paleoclimate history of these areas of the continent. The overall goal of the project was to improve the students analytical and quantitative skills; their ability to evaluate relationships between physical and chemical properties in ice cores, and to advance the understanding the impending consequences of climate change while engaging science, technology, engineering and mathematics (STEM). Student learning outcomes

Atmospheric Boundary Layer Dynamics Near Ross Island and Over West Antarctica.

NASA Astrophysics Data System (ADS)

Liu, Zhong

The atmospheric boundary layer dynamics near Ross Island and over West Antarctica has been investigated. The study consists of two parts. The first part involved the use of data from ground-based remote sensing equipment (sodar and RASS), radiosondes, pilot balloons, automatic weather stations, and NOAA AVHRR satellite imagery. The second part involved the use of a high resolution boundary layer model coupled with a three-dimensional primitive equation mesoscale model to simulate the observed atmospheric boundary layer winds and temperatures. Turbulence parameters were simulated with an E-epsilon turbulence model driven by observed winds and temperatures. The observational analysis, for the first time, revealed that the airflow passing through the Ross Island area is supplied mainly by enhanced katabatic drainage from Byrd Glacier and secondarily drainage from Mulock and Skelton glaciers. The observed diurnal variation of the blocking effect near Ross Island is dominated by the changes in the upstream katabatic airflow. The synthesized analysis over West Antarctica found that the Siple Coast katabatic wind confluence zone consists of two superimposed katabatic airflows: a relatively warm and more buoyant katabatic flow from West Antarctica overlies a colder and less buoyant katabatic airflow from East Antarctica. The force balance analysis revealed that, inside the West Antarctic katabatic wind zone, the pressure gradient force associated with the blocked airflow against the Transantarctic Mountains dominates; inside the East Antarctic katabatic wind zone, the downslope buoyancy force due to the cold air overlying the sloping terrain is dominant. The analysis also shows that these forces are in geostrophic balance with the Coriolis force. An E-epsilon turbulence closure model is used to simulate the diurnal variation of sodar backscatter. The results show that the model is capable of qualitatively capturing the main features of the observed sodar backscatter. To

Meteorites and Microbes: Meteorite Collection and Ice Sampling at Patriot Hills, Thiel Mountains, and South Pole, Antarctica

NASA Technical Reports Server (NTRS)

Sipiera, Paul P.; Hoover, Richard B.; Rose, M. Franklin (Technical Monitor)

2000-01-01

During the Antarctica 2000 Expedition, sponsored by the Planetary Studies Foundation, meteorites and ice microbiota were collected from the Patriot Hills, and Thiel Mountains of Antarctica and snow samples were at the South Pole. Psychrophilic and psychrotrophic microbiota were obtained from blue ice, cryoconite and ice-bubble systems. Twenty frozen meteorites were collected using aseptic techniques from the blue ice fields near the Moulton Escarpment of the Thiel Mountains (85 S, 94 W) and from the Morris Moraine of the Patriot Hills (80 S, 81 W) Ellsworth Mountains. These ice and meteorite samples are of potential significance to Astrobiology. They may help refine chemical and morphological biomarkers and refine characteristics of microbial life in one of the harshest environments on Earth. We discuss the Antarctica 2000 Expedition and provide preliminary results of the investigation of the meteorites and ice microbiota recovered.

Women Astronomers: Australia: Women astronomers in Australia

NASA Astrophysics Data System (ADS)

Bhathal, Ragbir

2001-08-01

Ragbir Bhathal summarizes the role played by women astronomers in Australia's astronomy, now and in the past. Australia has a great tradition in astronomy, from the early observations of Aboriginal people through the colonial drive to explore and understand, culminating in the established excellence of research there today. Women have contributed to this achievement in no small way, yet their contribution has been unremarked, if not ignored. Here I summarize the historical and present state of affairs and look forward to a brighter and more equitable future.

A Combined Observational and Modeling Approach to Study Modern Dust Transport from the Patagonia Desert to East Antarctica

NASA Technical Reports Server (NTRS)

Gasso, S.; Stein, A.; Marino, F.; Castellano, E.; Udisti, R.; Ceratto, J.

2010-01-01

presence of dust at approx.1500 km SW of South Africa five days after, the limited capabilities of existing satellite platforms to differentiate between aerosol types do not permit a definitive conclusion. In addition, the model simulations show dust lifting to the free troposphere as it travels south but it could not be confirmed by the satellite observations due to cloudiness. This work demonstrates that complementary information from existing transport models, satellite and surface data can yield a consistent picture of the dust transport from the Patagonia desert to Antarctica. It also illustrates the limitation of using any of these approaches individually to characterize the transport of dust in a heavily cloudy area.

Phylogeography of microbial phototrophs in the dry valleys of the high Himalayas and Antarctica.

PubMed

Schmidt, S K; Lynch, R C; King, A J; Karki, D; Robeson, M S; Nagy, L; Williams, M W; Mitter, M S; Freeman, K R

2011-03-07

High-elevation valleys in dry areas of the Himalayas are among the most extreme, yet least explored environments on Earth. These barren, rocky valleys are subjected to year-round temperature fluctuations across the freezing point and very low availability of water and nutrients, causing previous workers to hypothesize that no photoautotrophic life (primary producers) exists in these locations. However, there has been no work using modern biogeochemical or culture-independent molecular methods to test the hypothesis that photoautotrophs are absent from high Himalayan soil systems. Here, we show that although microbial biomass levels are as low as those of the Dry Valleys of Antarctica, there are abundant microbial photoautotrophs, displaying unexpected phylogenetic diversity, in barren soils from just below the permanent ice line of the central Himalayas. Furthermore, we discovered that one of the dominant algal clades from the high Himalayas also contains the dominant algae in culture-independent surveys of both soil and ice samples from the Dry Valleys of Antarctica, revealing an unexpected link between these environmentally similar but geographically very distant systems. Phylogenetic and biogeographic analyses demonstrated that although this algal clade is globally distributed to other high-altitude and high-latitude soils, it shows significant genetic isolation by geographical distance patterns, indicating local adaptation and perhaps speciation in each region. Our results are the first to demonstrate the remarkable similarities of microbial life of arid soils of Antarctica and the high Himalayas. Our findings are a starting point for future comparative studies of the dry valleys of the Himalayas and Antarctica that will yield new insights into the cold and dry limits to life on Earth.

An Evaluation of Antarctica as a Calibration Target for Passive Microwave Satellite Missions with Climate Data Record Applications

NASA Technical Reports Server (NTRS)

Kim, Edward

2011-01-01

Passive microwave remote sensing at L-band (1.4 GHz) is sensitive to soil moisture and sea surface salinity, both important climate variables. Science studies involving these variables can now take advantage of new satellite L-band observations. The first mission with regular global passive microwave observations at L-band is the European Space Agency's Soil Moisture and Ocean Salinity (SMOS), launched November, 2009. A second mission, NASA's Aquarius, was launched June, 201 I. A third mission, NASA's Soil Moisture Active Passive (SMAP) is scheduled to launch in 2014. Together, these three missions may provide a decade-long data record-provided that they are intercalibrated. The intercalibration is best performed at the radiance (brightness temperature) level, and Antarctica is proving to be a key calibration target. However, Antarctica has thus far not been fully characterized as a potential target. This paper will present evaluations of Antarctica as a microwave calibration target for the above satellite missions. Preliminary analyses have identified likely target areas, such as the vicinity of Dome-C and larger areas within East Antarctica. Physical sources of temporal and spatial variability of polar firn are key to assessing calibration uncertainty. These sources include spatial variability of accumulation rate, compaction, surface characteristics (dunes, micro-topography), wind patterns, and vertical profiles of density and temperature. Using primarily SMOS data, variability is being empirically characterized and attempts are being made to attribute observed variability to physical sources. One expected outcome of these studies is the potential discovery of techniques for remotely sensing--over all of Antarctica-parameters such as surface temperature.

Microbial taxonomic diversity and adaptation mechanisms in lithic ecosystems of the northern Victoria Land, Antarctica

NASA Astrophysics Data System (ADS)

Kim, O. S.; Lee, J.; Cho, J. H.; Kwon, M.; Cho, A.; Kim, M.; Woo, J.; Hong, S. G.; Lee, J.

2016-12-01

Rock is one of the best habitat for microorganisms in Antarctica, providing the good condition to avoid strong sunlight and wind. Furthermore, geochemistry in rock can provide as nutrients for microorganisms. Barren rock can be considered as an ecosystem by fouling, which is defined as the settlement of organisms and their growth. These life forms have the specialized mechanism to adapt the harsh environmental conditions such as a below subzero temperature, a unique annual light/dark cycle, wind chill and limited water availability and nutrient supply. However, little is known about the microbial communities and their adaptation mechanisms in this harsh environments. In this study, we focus on the microbial ecology in order to understand what kind of microorganisms are present based on culture-dependent and -independent methods collected barren rock samples from the northern Victoria Land, Antarctica. Additionally, we present the complete genome sequence of Cryobacterium arcticum PAMC 27867, one of the isolates from these rock samples, in order to understand the microbial adaptation strategies in lithic ecosystems, Antarctica.

Incorporating palaeoclimate data into water security planning and decision making - a case study from southeast Queensland, Australia

NASA Astrophysics Data System (ADS)

Kiem, Anthony; Vance, Tessa; Tozer, Carly; Roberts, Jason

2017-04-01

Decision makers in the water sector need to deal with existing hydroclimatic variability and uncertainty about future changes to climate and catchment conditions. Identifying solutions for hydroclimatic risk adaptation strategies that are both optimal and robust in the presence of variability and uncertainty presents a difficult challenge. A major reason for this challenge is the fact that the instrumental record in Australia is short ( 60-130 years) and fails to encompass enough climate variability to allow the calculation of robust statistics around the baseline risk of extreme events (e.g. multi-year droughts, decadal periods with clustering of major flood events). This climate variability is documented pre-1900 in palaeoclimate records from sources such as corals, tree-rings, freshwater and marine sediments. Despite being remote from Queensland, a high resolution and highly correlated palaeoclimate record from the Law Dome ice cores in Antarctica (Vance et al. 2015) is also now available and has identified eight mega-droughts (lasting from 5-39 years) during 1000-2009 AD. Most importantly, the palaeoclimate information confirms that the post-1900 instrumental period (i.e. the period on which all water resources infrastructure, policy, operation rules and strategies is based) does not capture the full range of variability that has occurred. Other work also clearly shows that, out to 2050 at least, impacts associated with natural variability significantly exceed even the worst-case climate change scenarios (i.e. obtained from Global Climate Models run under the highest emission scenarios). This presentation will demonstrate how the Law Dome ice cores from Antarctica have been used to produce a highly accurate, 1000 year, annual and seasonal resolution, hydroclimate reconstruction (i.e. precipitation and streamflow) for the southeast Queensland region of Australia. We will then show how the palaeoclimate data has been incorporated into the South East Queensland

Deglacial temperature history of West Antarctica

NASA Astrophysics Data System (ADS)

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.

The origin of platyrrhines: An evaluation of the Antarctic scenario and the floating island model.

PubMed

Houle, A

1999-08-01

This paper evaluates whether 1) protoplatyrrhines could have migrated to South America via Antarctica, and 2) the floating island model is a plausible transoceanic mode of dispersal for land vertebrates like protoplatyrrhines. Results show that Eocene Antarctica and Australia supported large and dense forests, and that the Antarctic fauna was comprised of many species of vertebrates, including placental and marsupial land mammals. However, no primate remains have ever been reported from these continents. Antarctica and South America were connected until the Middle Eocene (i.e., after the oldest Asian anthropoids), but two major water barriers existed between Antarctica and Asia since the Early Eocene. The Eocene and Oligocene water gap separating Africa and Antarctica was excessively large. Thus, all scenarios involving an Antarctic route have been rejected. The African scenario is difficult to falsify because only one water barrier existed, both paleowinds and paleocurrents were favorable, and Paleogene African anthropoids show phylogenetic affinities to platyrrhines. I tested whether a journey on a hypothetical floating island over the Paleogene Atlantic Ocean exceeds the survival limit of a genetically viable group of animals such as protoplatyrrhines. Studies of water deprivation suggest that they could have been able, with a body weight averaging 1 kg, to survive without water for at least 13 days. I have used the present Atlantic Ocean as a model for the velocity of Paleogene paleowinds and paleocurrents. Considering winds as the key accelerating force of floating islands, the Paleogene Atlantic water barrier could have been crossed, in the most conservative scenario, in 8 days at 50 Mya, 11 days at 40 Mya, and 15 days at 30 Mya. In order to survive a transoceanic journey, however, protoplatyrrhines had to be preadapted to strong seasonal variations in water availability in their original (African) environment. Once on the sea, their brains would have

Solar Activity and Motions in the Solar Chromosphere and Corona at the 2012 and 2013 Total and Annular Eclipses in the U.S., Australia, and Africa

NASA Astrophysics Data System (ADS)

Pasachoff, Jay M.; Babcock, B. A.; Davis, A. B.; Demianski, M.; Lucas, R.; Lu, M.; Dantowitz, R.; Rusin, V.; Saniga, M.; Seaton, D. B.; Gaintatzis, P.; Voulgaris, A.; Seiradakis, J. H.; Gary, D. E.; Shaik, S. B.

2014-01-01

Our studies of the solar chromosphere and corona at the 2012 and 2013 eclipses shortly after cycle maximum 24 (2011/2012) of solar activity (see: http://www.swpc.noaa.gov/SolarCycle/) involved radio observations of the 2012 annular eclipse with the Jansky Very Large Array, optical observations of the 2012 total eclipse from Australia, optical observations of the 2013 annular eclipse from Tennant Creek, Australia, and the 3 November 2013 total solar eclipse from Gabon. Our observations are coordinated with those from solar spacecraft: Solar Dynamics Observatory AIA and HMI, Hinode XRT and SOT, SOHO LASCO and EIT, PROBA2 SWAP, and STEREO SECCHI. Our 2012 totality observations include a CME whose motion was observed with a 37-minute interval. We include first results from the expedition to Gabon for the 3 November 2013 eclipse, a summary of eclipse results from along the path of totality across Africa, and a summary of the concomitant spacecraft observations. The Williams College 2012 expeditions were supported in part by NSF grant AGS-1047726 from Solar Terrestrial Research/NSF AGS, and by the Rob Spring Fund and Science Center funds at Williams. The JVLA is supported by the NSF. The Williams College 2013 total-eclipse expedition was supported in part by grant 9327-13 from the Committee for Research and Exploration of the National Geographic Society. ML was also supported in part by a Grant-In-Aid of Research from the National Academy of Sciences, administered by Sigma Xi, The Scientific Research Society (Grant ID: G20120315159311). VR and MS acknowledge support for 2012 from projects VEGA 2/0003/13 and NGS-3139-12 of the National Geographic Society. We are grateful to K. Shiota (Japan) for kindly providing us with some of his 2012 eclipse coronal images. We thank Alec Engell (Montana State U) for assistance on site, and Terry Cuttle (Queensland Amateur Astronomers) for help with site arrangements. We thank Aram Friedman (Ansible Technologies), Michael Kentrianakis

Antarctica and Global Environmental Change - Lessons from the Past Inform Climate Change Policy Today

NASA Astrophysics Data System (ADS)

Dunbar, R. B.; Scientific Team Of Odp Drilling Leg 318; Andrill Science Team

2011-12-01

Antarctic's continental ice, sea ice, and the broader Southern Ocean form a coupled and complex climate system that interacts in important yet poorly understood ways with the low and mid-latitudes. Because of its unusual sovereignty status and the fact that there is no indigenous human population, information about climate change in Antarctica penetrates the policy world less readily than findings from other regions. Yet, Antarctica's potential to impact climate change globally is disproportionately large. Vulnerable portions of the ice sheet may contribute up to 3 to 5 meters of sea level rise in the coming centuries, including significant amounts within the next 50 years. Loss of sea ice and other changes in the Southern Ocean may reduce oceanic uptake of excess atmospheric carbon dioxide, exacerbating global warming worldwide. Antarctica's impact on the Southern Hemisphere wind field is now well-established, contributing to ongoing decadal-scale perturbations in continental precipitation as well as major reorganizations of Southern Ocean food chains. Recent scientific drilling programs in the Ross Sea and off Wilkes Land, Antarctica, provide valuable insights into past climatic and biogeochemical change in Antarctica, insights of great relevance to international and national climate change policy. In this paper, we discuss polar amplification, sea level variability coupled to Antarctic ice volume, and response timescales as seen through the lens of past climate change. One key result emerging from multiple drilling programs is recognition of unanticipated dynamism in the Antarctic ice sheet during portions of the Pliocene (at a time with pCO2 levels equivalent to those anticipated late this century) as well as during "super-interglacials" of the Pleistocene. Evidence for substantially warmer ocean temperatures and reduced sea ice cover at these times suggests that polar amplification of natural climate variability, even under scenarios of relative small amounts

Coastal-change and glaciological map of the Bakutis Coast, Antarctica

USGS Publications Warehouse

Swithinbank, Charles; Williams, Richard S.; Ferrigno, Jane G.; Seekins, B.A.; Lucchita, B.K.; Rosanova, Christine E.

1997-01-01

Changes in the area and volume of the polar ice sheets are intricately linked to changes in global climate, and the resulting changes in sea level may severely impact the densely populated coastal regions on Earth. Loss of the West Antarctic part of the Antarctic ice sheet alone could cause a sea-level rise of approximately 6 m. The potential sea-level rise after melting of the entire Antarctic ice sheet is estimated to be 65 m to 73 m. In spite of its importance, the mass balance (the net volumetric gain or loss) of the Antarctic ice sheet is poorly known; it is not known whether the ice sheet is growing or shrinking. As a result, measurement of changes in the Antarctic ice sheet was given a very high priority in recommendations by the Polar Research Board of the National Research Council (1986), by the Scientific Committee on Antarctic Research (SCAR) (1989), and by the National Science Foundation's (1990) Division of Polar Programs. An archive of early 1970's Landsat 1, 2, and 3 Multispectral Scanner (MSS) images of Antarctica and the fact that the repeat coverage with satellite images provided an excellent means of documenting changes in the coastline of Antarctica provided the impetus for carrying out a comprehensive analysis of the glaciological features of the coastal regions and changes in ice fronts of Antarctica. The project was later modified to include Landsat 4 and 5 MSS and Thematic Mapper (TM) and RADARSAT images to compare changes over a 20- to 25- year time interval and to prepare a series of 24 1:1,000,000-scale and 1 1:5,000,000-scale U.S. Geological Survey Geologic Investigations Series Maps ('I-Maps') (Williams and others, 1995; Williams and Ferrigno, 1998; and Ferrigno and others, 2002) in both paper and digital format.

The 1994 EUROMET collection of micrometeorites at Cap-Prudhomme, Antarctica

NASA Astrophysics Data System (ADS)

Maurette, M.; Immel, G.; Engrand, C.; Kurat, G.; Pillinger, C. T.

1994-07-01

Advance funding from IFRTP (Institut Francais pour la Recherche et pour la Technique Polaire) for micrometeorite collection at Cap-Prudhomme has allowed construction of a new micrometeorite 'factory,' conceived to greatly reduce contamination of the ultraclean ice by our activities. The potential problems include fly ash, rust grains, fuel spills 'sticking to the shoes,' and trace elements from the plasticizers used in plastic tubing. In the new factory, intended to produce and then cycle 10-15 tons of melt ice water per day, all parts exposed to water were replaced by either stainless steel or teflon. After examination with a microscope and their transfer into teflon and or glass vials, all samples were frozen the day of their collection. The factory operated from December 15, 1993, through February 6, 1994. Problems included injuries as well as very bad weather conditions, characterized by both the heaviest snow falls observed and unexpected gusts from a blizzard. Also, several new components of the factory did not function properly under the extreme conditions of Antarctica. Our major objective was to obtain the 'cleanest' and 'purest' 25-50 microns micrometeorites ever collected in Antarctica, for comparison with stratospheric Interplanetary Dust Particles (IDPs). We could not fulfill this premise, but we recovered the best 100-400-micron-size fraction of 'giant' micrometeorites ever collected on Earth. Our 26 daily collections are listed,refering to an 'index of quality.' Aliquots of these daily collections will be distributed to major institutions in Austria, England, the U.S.A., and Japan, to be preserved for future generations. The Antarctica ice sheet is truly a gigantic, ultraclean, and inexhaustible micrometeorite collector, but it is very tricky to recover 'ultraclean' micrometeorites from it.

The International Geophysical Year in Antarctica: Uncommon Collaborations, Unprecedented Results

ERIC Educational Resources Information Center

Belanger, Dian Olson

2004-01-01

When 1 July 1957 ''dawned'' in the dark of the south polar night, Americans at seven scientific stations scattered across Antarctica officially began systematic, synoptic observations of the air above and ice below. Joining scientists from 11 other countries on the polar continent, they were part of the International Geophysical Year, an 18-month…

Photochemical production of O3 in biomass burning plumes in the boundary layer over northern Australia

NASA Astrophysics Data System (ADS)

Takegawa, N.; Kondo, Y.; Ko, M.; Koike, M.; Kita, K.; Blake, D. R.; Hu, W.; Scott, C.; Kawakami, S.; Miyazaki, Y.; Russell-Smith, J.; Ogawa, T.

2003-05-01

In situ aircraft measurements of ozone (O3) and its precursors were made over northern Australia in August-September 1999 during the Biomass Burning and Lightning Experiment Phase B (BIBLE-B). A clear positive correlation of O3 with carbon monoxide (CO) was found in biomass burning plumes in the boundary layer (<3 km). The ΔO3/ΔCO ratio (linear regression slope of O3-CO correlation) is found to be 0.12 ppbv/ppbv, which is comparable to the ratio of 0.15 ppbv/ppbv observed at 0-4 km over the Amazon and Africa in previous studies. The net flux of O3 exported from northern Australia during BIBLE-B is estimated to be 0.3 Gmol O3/day. In the biomass burning region, large enhancements of O3 were coincident with the locations of biomass burning hot spots, suggesting that major O3 production occurred near fires (horizontal scale <50 km).

Regional magnetic anomaly constraints on continental rifting

NASA Technical Reports Server (NTRS)

Vonfrese, R. R. B.; Hinze, W. J.; Olivier, R.; Bentley, C. R.

1985-01-01

Radially polarized MAGSAT anomalies of North and South America, Europe, Africa, India, Australia and Antarctica demonstrate remarkably detailed correlation of regional magnetic lithospheric sources across rifted margins when plotted on a reconstruction of Pangea. These major magnetic features apparently preserve their integrity until a superimposed metamorphoric event alters the magnitude and pattern of the anomalies. The longevity of continental scale magnetic anomalies contrasts markedly with that of regional gravity anomalies which tend to reflect predominantly isostatic adjustments associated with neo-tectonism. First observed as a result of NASA's magnetic satellite programs, these anomalies provide new and fundamental constraints on the geologic evolution and dynamics of the continents and oceans. Accordingly, satellite magnetic observations provide a further tool for investigating continental drift to compliment other lines of evidence in paleoclimatology, paleontology, paleomagnetism, and studies of the radiometric ages and geometric fit of the continents.

Mesoscale cyclogenesis dynamics over the southwestern Ross Sea, Antarctica

NASA Astrophysics Data System (ADS)

Carrasco, Jorge F.; Bromwich, David H.

1993-07-01

Previous work has shown that frequent mesoscale cyclogenesis adjacent to Franklin Island is linked to the strong and persistent katabatic winds from East Antarctica which funnel into Terra Nova Bay and then blow out over the southwestern Ross Sea. Four mesoscale cyclones that formed near Terra Nova Bay between February 16 and 20, 1988 are examined to more clearly define the governing mechanisms. These events are investigated using all available observations, including automatic weather station data, high-resolution satellite images, satellite soundings, and hemispheric synoptic analyses. The first two cyclones formed on low-level baroclinic zones established by the synoptic scale advection of warm moist air toward the cold continental air blowing gently from East Antarctica. In the second case, baroclinic instability of this small-scale cold front was apparently triggered by the enhanced upward vertical motion associated with the approach of a midtropospheric trough. The third mesocyclone formed shortly after on a baroclinic zone over the polar plateau; the second vortex completely disrupted the usual katabatic drainage over the plateau and forced warm moist air over the coastal slopes. All three cyclones moved to the north in the prevailing cyclonic flow, but the plateau vortex lasted for only 6 hours. The fourth mesoscale low formed in conjunction with an abrupt and intense surge of katabatic air from Terra Nova Bay which resharpened the coastal baroclinic zone. At the same time a transiting midtropospheric trough probably associated with lower tropospheric upward vertical motion apparently accelerated the katabatic winds and triggered the vortex formation. A similar katabatic wind-forced mesocyclone formed near Byrd Glacier. The two vortices moved to the east-southeast and northeast, respectively, apparently being steered by the generating katabatic airstreams, and merged just to the north of the Ross Ice Shelf. The combined vortex reintensified as another

The Bess-Polar II Long Duration Flight Above Antarctica

NASA Technical Reports Server (NTRS)

Sasaki, Makoto; Yamamoto, Akira; Yoshimura, Koji; Makida, Yasuhiro; Matsuda, Shinya; Hasegawa, Masaya; Horikoshi, Atsushi; Tanaka, Ken-ichi; Suzuki, Junichi; Nishimura, Jun;

Aeromagnetic evidence for a major strike-slip fault zone along the boundary between the Weddell Sea Rift and East Antarctica

NASA Astrophysics Data System (ADS)

Jordan, T. A.; Ferraccioli, F.; Ross, N.; Siegert, M. J.; Corr, H.; Leat, P. T.; Bingham, R. G.; Rippin, D. M.; le Brocq, A.

2012-04-01

The >500 km wide Weddell Sea Rift was a major focus for Jurassic extension and magmatism during the early stages of Gondwana break-up, and underlies the Weddell Sea Embayment, which separates East Antarctica from a collage of crustal blocks in West Antarctica. Here we present new aeromagnetic data combined with airborne radar and gravity data collected during the 2010-11 field season over the Institute and Moeller ice stream in West Antarctica. Our interpretations identify the major tectonic boundaries between the Weddell Sea Rift, the Ellsworth-Whitmore Mountains block and East Antarctica. Digitally enhanced aeromagnetic data and gravity anomalies indicate the extent of Proterozoic basement, Middle Cambrian rift-related volcanic rocks, Jurassic granites, and post Jurassic sedimentary infill. Two new joint magnetic and gravity models were constructed, constrained by 2D and 3D magnetic depth-to-source estimates to assess the extent of Proterozoic basement and the thickness of major Jurassic intrusions and post-Jurassic sedimentary infill. The Jurassic granites are modelled as 5-8 km thick and emplaced at the transition between the thicker crust of the Ellsworth-Whitmore Mountains block and the thinner crust of the Weddell Sea Rift, and within the Pagano Fault Zone, a newly identified ~75 km wide left-lateral strike-slip fault system that we interpret as a major tectonic boundary between East and West Antarctica. We also suggest a possible analogy between the Pagano Fault Zone and the Dead Sea transform. In this scenario the Jurassic Pagano Fault Zone is the kinematic link between extension in the Weddell Sea Rift and convergence across the Pacific margin of West Antarctica, as the Dead Sea transform links Red Sea extension to compression within the Zagros Mountains.

Defining the ecologically relevant mixed-layer depth for Antarctica's coastal seas

NASA Astrophysics Data System (ADS)

Carvalho, Filipa; Kohut, Josh; Oliver, Matthew J.; Schofield, Oscar

2017-01-01

Mixed-layer depth (MLD) has been widely linked to phytoplankton dynamics in Antarctica's coastal regions; however, inconsistent definitions have made intercomparisons among region-specific studies difficult. Using a data set with over 20,000 water column profiles corresponding to 32 Slocum glider deployments in three coastal Antarctic regions (Ross Sea, Amundsen Sea, and West Antarctic Peninsula), we evaluated the relationship between MLD and phytoplankton vertical distribution. Comparisons of these MLD estimates to an applied definition of phytoplankton bloom depth, as defined by the deepest inflection point in the chlorophyll profile, show that the maximum of buoyancy frequency is a good proxy for an ecologically relevant MLD. A quality index is used to filter profiles where MLD is not determined. Despite the different regional physical settings, we found that the MLD definition based on the maximum of buoyancy frequency best describes the depth to which phytoplankton can be mixed in Antarctica's coastal seas.

High Resolution Spatial Mapping of Human Footprint across Antarctica and Its Implications for the Strategic Conservation of Avifauna.

PubMed

Pertierra, Luis R; Hughes, Kevin A; Vega, Greta C; Olalla-Tárraga, Miguel Á

2017-01-01

Human footprint models allow visualization of human spatial pressure across the globe. Up until now, Antarctica has been omitted from global footprint models, due possibly to the lack of a permanent human population and poor accessibility to necessary datasets. Yet Antarctic ecosystems face increasing cumulative impacts from the expanding tourism industry and national Antarctic operator activities, the management of which could be improved with footprint assessment tools. Moreover, Antarctic ecosystem dynamics could be modelled to incorporate human drivers. Here we present the first model of estimated human footprint across predominantly ice-free areas of Antarctica. To facilitate integration into global models, the Antarctic model was created using methodologies applied elsewhere with land use, density and accessibility features incorporated. Results showed that human pressure is clustered predominantly in the Antarctic Peninsula, southern Victoria Land and several areas of East Antarctica. To demonstrate the practical application of the footprint model, it was used to investigate the potential threat to Antarctica's avifauna by local human activities. Relative footprint values were recorded for all 204 of Antarctica's Important Bird Areas (IBAs) identified by BirdLife International and the Scientific Committee on Antarctic Research (SCAR). Results indicated that formal protection of avifauna under the Antarctic Treaty System has been unsystematic and is lacking for penguin and flying bird species in some of the IBAs most vulnerable to human activity and impact. More generally, it is hoped that use of this human footprint model may help Antarctic Treaty Consultative Meeting policy makers in their decision making concerning avifauna protection and other issues including cumulative impacts, environmental monitoring, non-native species and terrestrial area protection.

Culturable bacterial diversity at the Princess Elisabeth Station (Utsteinen, Sør Rondane Mountains, East Antarctica) harbours many new taxa.

PubMed

Peeters, Karolien; Ertz, Damien; Willems, Anne

2011-07-01

We studied the culturable heterotrophic bacterial diversity present at the site of the new Princess Elisabeth Station at Utsteinen (Dronning Maud Land, East Antarctica) before construction. About 800 isolates were picked from two terrestrial microbial mat samples after incubation on several growth media at different temperatures. They were grouped using rep-PCR fingerprinting and partial 16S rRNA gene sequencing. Phylogenetic analysis of the complete 16S rRNA gene sequences of 93 representatives showed that the isolates belonged to five major phyla: Actinobacteria, Bacteroidetes, Proteobacteria, Firmicutes and Deinococcus-Thermus. Isolates related to the genus Arthrobacter were the most prevalent whereas the genera Hymenobacter, Deinococcus, Cryobacterium and Sphingomonas were also recovered in high numbers in both samples. A total of 35 different genera were found, the majority of which has previously been reported from Antarctica. For the genera Aeromicrobium, Aurantimonas, Rothia, Subtercola, Tessaracoccus and Xylophilus, this is the first report in Antarctica. In addition, numerous potential new species and new genera were recovered; many of them currently restricted to Antarctica, particularly in the phyla Bacteroidetes and Deinococcus-Thermus. Copyright © 2011 Elsevier GmbH. All rights reserved.

Algae Reefs in Shark Bay, Western Australia, Australia

NASA Technical Reports Server (NTRS)

1990-01-01

Numerous algae reefs are seen in Shark Bay, Western Australia, Australia (26.0S, 113.5E) especially in the southern portions of the bay. The south end is more saline because tidal flow in and out of the bay is restricted by sediment deposited at the north and central end of the bay opposite the mouth of the Wooramel River. This extremely arid region produces little sediment runoff so that the waters are very clear, saline and rich in algae.

Australia's contribution to global immunisation.

PubMed

Ruff, Tilman A; Taylor, Kate; Nolan, Terry

2012-12-01

To review Australian contributions to global immunisation. We summarise Australian scientific and program contributions to vaccines and global immunisation, describe key developments and strengths in Australia's national immunisation program, and outline how both of these can link with Australia's increasing international development budget to build Australia's future contribution to global immunisation. Australian contributions to vaccines and immunisation have been substantial, and Australia offers a range of good practices in its domestic and development approaches. There are major opportunities to build on this strong track record. These include committing to help roll out important new life-saving vaccines against pneumococcal disease, rotavirus and human papilloma virus (HPV) to the children who need them most, but whose communities can least afford them. Australia is one of a few countries expanding their aid budgets towards 0.7% development assistance and other development commitments. Given the importance of immunisation to health gains, Australia is well placed to expand its investment in immunisation within its development portfolio. The GAVI Alliance is the best-established global mechanism to do this. Additionally, however, Australia could harness other national and regional mechanisms to support low and middle-income countries, thereby complementing GAVI's focus and global needs. © 2012 The Authors. ANZJPH © 2012 Public Health Association of Australia.

Chemical characterization of microbial-dominated soil organic matter in the Garwood Valley, Antarctica

NASA Astrophysics Data System (ADS)

Feng, Xiaojuan; Simpson, André J.; Gregorich, Edward G.; Elberling, Bo; Hopkins, David W.; Sparrow, Ashley D.; Novis, Philip M.; Greenfield, Lawrence G.; Simpson, Myrna J.

2010-11-01

Despite its harsh environmental conditions, terrestrial Antarctica contains a relatively large microbial biomass. Natural abundance carbon and nitrogen stable isotope signatures of organic materials in the dry valleys indicate mixed provenance of the soil organic matter (SOM) with varying proportions of contributions from lichens, mosses, lake-derived algae and cyanobacteria. Here we employed two complementary analytical techniques, biomarker measurements by gas chromatography/mass spectrometry and solution-state 1H nuclear magnetic resonance spectroscopy, to provide further information at a molecular-level about the composition and possible source of SOM in the Garwood Valley, Antarctica. The predominance of branched alkanes and short-chain lipids in the solvent extracts indicates that the primary contribution to the SOM was microbial-derived. Chemical structures in the NaOH extracts from soils were also dominated by amide, peptides, and a CH 3-dominating aliphatic region that were characteristic of microbial signatures. Furthermore, the SOM in the Garwood Valley contained compounds that were different from those in the cyanobacteria-dominated mat from a nearby lake (including monoethyl alkanes and enriched side-chain protons). This observation suggests that easily degradable carbon sources from the nearby lake did not dominate the SOM, which is consistent with a fast turnover of the mat-derived organic matter found in the valley. This study highlights the important role of native soil microbes in the carbon transformation and biogeochemistry in terrestrial Antarctica.

Antarctica Cloud Cover for October 2003 from GLAS Satellite Lidar Profiling

NASA Technical Reports Server (NTRS)

Spinhirne, J. D.; Palm, S. P.; Hart, W. D.

2005-01-01

Seeing clouds in polar regions has been a problem for the imagers used on satellites. Both clouds and snow and ice are white, which makes clouds over snow hard to see. And for thermal infrared imaging both the surface and the clouds cold. The Geoscience Laser Altimeter System (GLAS) launched in 2003 gives an entirely new way to see clouds from space. Pulses of laser light scatter from clouds giving a signal that is separated in time from the signal from the surface. The scattering from clouds is thus a sensitive and direct measure of the presence and height of clouds. The GLAS instrument orbits over Antarctica 16 times a day. All of the cloud observations for October 2003 were summarized and compared to the results from the MODIS imager for the same month. There are two basic cloud types that are observed, low stratus with tops below 3 km and high cirrus form clouds with cloud top altitude and thickness tending at 12 km and 1.3 km respectively. The average cloud cover varies from over 93 % for ocean and coastal regions to an average of 40% over the East Antarctic plateau and 60-90% over West Antarctica. When the GLAS monthly average cloud fractions are compared to the MODIS cloud fraction data product, differences in the amount of cloud cover are as much as 40% over the continent. The results will be used to improve the way clouds are detected from the imager observations. These measurements give a much improved understanding of distribution of clouds over Antarctica and may show how they are changing as a result of global warming.

Reliability Analysis of Main-axis Control System of the Equatorial Antarctica Astronomical Telescope Based on Fault Tree

NASA Astrophysics Data System (ADS)

LI, Y.; Yang, S. H.

2017-05-01

The Antarctica astronomical telescopes work chronically on the top of the unattended South Pole, and they have only one chance to maintain every year. Due to the complexity of the optical, mechanical, and electrical systems, the telescopes are hard to be maintained and need multi-tasker expedition teams, which means an excessive awareness is essential for the reliability of the Antarctica telescopes. Based on the fault mechanism and fault mode of the main-axis control system for the equatorial Antarctica astronomical telescope AST3-3 (Antarctic Schmidt Telescopes 3-3), the method of fault tree analysis is introduced in this article, and we obtains the importance degree of the top event from the importance degree of the bottom event structure. From the above results, the hidden problems and weak links can be effectively found out, which will indicate the direction for promoting the stability of the system and optimizing the design of the system.

The subglacial roughness of Antarctica: Analogs, interpretation and implications for ice thickness uncertainities

NASA Astrophysics Data System (ADS)

Young, D. A.; Grima, C.; Greenbaum, J. S.; Beem, L.; Cavitte, M. G.; Quartini, E.; Kempf, S. D.; Roberts, J. L.; Siegert, M. J.; Ritz, C.; Blankenship, D. D.

2017-12-01

Over the last twenty five years, extensive ice penetrating radar (IPR) coverage of Antarctica has been obtained, at lines spacings down to 1 km in some cases. However, many glacial processes occur at finer scales, so infering likely landscape parameters is required for a useful interpolation between lines. Profile roughness is also important for understanding the uncertainties inherent in IPR observations. Subglacial roughness has also been used to infer large scale bed rock properties and history. Similar work has been conducted on a regional basis with complilations of data from the 1970's and more recent local studies. Here we present a compilation of IPR-derived profile roughness data covering three great basins of Antarctica: the Byrd Subglacial Basin in West Antarctica, and the Wilkes Subglacial Basin and Aurora Subglacial Basins in East Antarctica; and treat these data using root mean squared deviation (RMSD). Coverage is provied by a range of IPR systems with varying vintages with differing instrument and processing parameters; we present approaches to account for the differences between these systems. We use RMSD, a tool commonly used in planetary investigations, to investigate the self-affine behaviour of the bed at kilometer scales and extract fractal parameters from the data to predict roughness and uncertainties in ice thickness measurement. Lastly, we apply a sensor model to a range of bare-earth terrestrial digital elevation models to futher understand the impact of the sensor model on the inference of subglacial topography and roughness, and to the first order analogies for the lithology of the substrate. This map of roughness, at scales between the pulse limited radar footprint and typical line spacings, provides an understanding of the distribution of Paleogene subglacial sediments, insight in to the distribution of uncertainties and a potential basal properties mask for ice sheet models. A particular goal of this map is to provide insight into

Morphological evidence and direct estimates of rapid melting beneath Totten Glacier Ice Shelf, East Antarctica

NASA Astrophysics Data System (ADS)

Greenbaum, Jamin; Schroeder, Dustin; Grima, Cyril; Habbal, Feras; Dow, Christine; Roberts, Jason; Gwyther, David; van Ommen, Tas; Siegert, Martin; Blankenship, Donald

2017-04-01

Totten Glacier drains at least 3.5 meters of eustatic sea level potential from marine-based ice in the Aurora Subglacial Basin (ASB) in East Antarctica, more than the combined total of all glaciers in West Antarctica. Totten Glacier has been the most rapidly thinning glacier in East Antarctica since satellite altimetry time series began and the nature of the thinning suggests that it is driven by enhanced basal melting due to ocean processes. While grounded ice thinning rates have been steady, recent work has shown that Totten's floating ice shelf may not have the same thinning behavior; as a result, it is critical to observe ice shelf and cavity boundary conditions and basal processes to understand this apparent discrepancy. Warm Modified Circumpolar Deep Water (MCDW), which has been linked to glacier retreat in West Antarctica, has been observed in summer and winter on the nearby Sabrina Coast continental shelf and deep depressions in the seafloor provide access for MCDW to reach the ice shelf cavity. Given its northern latitude, numerical ice sheet modeling indicates that Totten Glacier may be prone to retreat caused by hydrofracture in a warming climate, so it is important to understand how intruding MCDW is affecting thinning of Totten Glacier's ice shelf. Here we use post-processed, focused airborne radar observations of the Totten Glacier Ice Shelf to delineate multi-km wide basal channels and flat basal terraces associated with high basal reflectivity and specularity (flatness) anomalies and correspondingly large ice surface depressions that indicate active basal melting. Using a simple temperature-attenuation model, and basal roughness corrections, we present basal melt rates associated with the radar reflection and specularity anomalies and compare them to those derived from numerical ocean circulation modeling and an ice flow divergence calculation. Sub-ice shelf ocean circulation modeling and under-ice robotic observations of Pine Island Glacier Ice

NASA Satellite View of Antarctica

NASA Image and Video Library

2017-12-08

NASA image acquired November 2, 2011 The Moderate Resolution Imaging Spectroradiometer (MODIS) instrument on NASA's Terra satellite captured this image of the Knox, Budd Law Dome, and Sabrina Coasts, Antarctica on November 2, 2011 at 01:40 UTC (Nov. 1 at 9:40 p.m. EDT). Operation Ice Bridge is exploring Antarctic ice, and more information can be found at www.nasa.gov/icebridge. Image Credit: NASA Goddard MODIS Rapid Response Team NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

Ice-Shelf Melting Around Antarctica

NASA Astrophysics Data System (ADS)

Rignot, E.; Jacobs, S.; Mouginot, J.; Scheuchl, B.

2013-07-01

We compare the volume flux divergence of Antarctic ice shelves in 2007 and 2008 with 1979 to 2010 surface accumulation and 2003 to 2008 thinning to determine their rates of melting and mass balance. Basal melt of 1325 ± 235 gigatons per year (Gt/year) exceeds a calving flux of 1089 ± 139 Gt/year, making ice-shelf melting the largest ablation process in Antarctica. The giant cold-cavity Ross, Filchner, and Ronne ice shelves covering two-thirds of the total ice-shelf area account for only 15% of net melting. Half of the meltwater comes from 10 small, warm-cavity Southeast Pacific ice shelves occupying 8% of the area. A similar high melt/area ratio is found for six East Antarctic ice shelves, implying undocumented strong ocean thermal forcing on their deep grounding lines.

Revised model of the East Gondwana Break-up and formation of the Gateway between India and Antarctica

NASA Astrophysics Data System (ADS)

Leitchenkov, German; Guseva, Julia; Ivanov, Sergey; Golynsky, Alexander

2017-04-01

The history of break-up and sea-floor spreading between India and Antarctica long remained vague mainly because of the data scarcity off both continents. Geophysical studies carried out recently in the Enderby Basin (Southern Indian Ocean) provided new information and advanced our knowledge on this problem. Magnetic surveys discovered there a prominent linear high-amplitude bipolar magnetic anomaly (HBMA), which stretched more than 1000 km westward from the southern Kerguelen Plateau. This anomaly was interpreted by many as the contact between stretched continental crust and oceanic crust. Gaina et al. (1987) suggested the existence of an abandoned spreading centre in the eastern Enderby Basin and inferred that the Elan Bank (established as a microcontinent) was isolated from the India margin by a ridge jump at about M0 chron (c. 120 Ma). South of an abandoned spreading centre, they identified a series of magnetic anomalies from M2 to M9. New magnetic data collected in the western Enderby Basin and revision of all available geophysical data gives a new notion on the geodynamics of the East Gondwana break-up and separation of India from Antarctica. According to a new model, the HBMA corresponds to M34o chrone and its increased intensity can be explained by the emplacement of the Kerguelen Hotspot and thickening of the oceanic (magmatic) crust at that time. A relationship between hot-spots and appearance of high-amplitude magnetic anomalies is observed elsewhere in the World Ocean. In our model, the continent-ocean boundary is located about 150 km landward of the HBMA, and anomalies from M4 to M0 are identified between these features. The ridge jump (which isolated the Elan Bank) occurred about 110 Ma ago when the Kerguelen Hotspot moved toward the India margin. This model is consistent with the interpretation of sea-floor spreading history off Western Australia. An earlier (around 120 Ma) ridge jump probably occurred in the area of the southern Kerguelen Plateau

Geochemical markers of soil anthropogenic contaminants in polar scientific stations nearby (Antarctica, King George Island).

PubMed

Prus, Wojciech; Fabiańska, Monika J; Łabno, Radosław

2015-06-15

The organic contamination of Antarctic soils and terrestrial sediments from nearby of five polar scientific stations on King George Island (Antarctica) was investigated. Gas chromatography-mass spectrometry (GC-MS) was applied to find composition of dichloromethane extracts of soil and terrestrial sediments. The presence of geochemical markers, such as n-alkanes, steranes, pentacyclic triterpenoids, and alkyl PAHs, their distribution types, and values of their ratios indicates the predominating source of organic fossil fuels and products of their refining rather than from the natural Antarctic environment. Fossil fuel-originated compounds well survived in conditions of Antarctic climate over long times thus enabling to characterize geochemical features of source fossil fuel identified as petroleum expelled from kerogen II of algal/bacterial origins deposited in sub-oxic conditions and being in the middle of catagenesis. Both microbial activity and water leaching play an important role in degradation of terrestrial oil spills in the Antarctica climate, and petroleum alteration occurs lowly over long periods of time. Synthetic anthropogenic compounds found in terrestrial Antarctica sediments included diisopropylnaphthalenes, products of their sulfonates degradation in paper combustion, and organophosporus compounds used as retardants and plasticizers. Copyright © 2015 Elsevier B.V. All rights reserved.

Reasons for medical consultation among members of the Indian Scientific Expeditions to Antarctica

PubMed Central

Bhatia, Abhijeet; Malhotra, Pradip; Agarwal, Ashok Kumar

2013-01-01

The article attempts to analyze the disease burden in a healthy, pre-screened population subjected to prolonged residence in the hostile environment of Antarctica. This retrospective epidemiological study was conducted utilizing data from medical consultation room on board the Indian Antarctic expedition vessels and at Indian Antarctic station, Maitri from seven Indian Scientific Expeditions to Antarctica (ISEA). The study group (n=327) consisted of 325 men and two women. The total number of medical room consultations was 1989. Maximum consultations were for injuries (27.25%); 14.68% were musculoskeletal and 10.31% were bruises and lacerations. Disturbances of gastrointestinal tract (19.66%) were the second most common disorders. Psychological disturbances accounted for 2.66% consultations. Cold injuries constituted 2.01% consultations and photophthalmia accounted for 1.06% consultations. PMID:23423959

My IGY in Antarctica

NASA Technical Reports Server (NTRS)

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.

Glycerol acyl-transfer kinetics of a circular permutated Candida antarctica Lipase B

USDA-ARS?s Scientific Manuscript database

Triacylglycerols containing a high abundance of unusual fatty acids, such as y-linolenic acid, or novel arylaliphatic acids, such as ferulic acid, are useful in pharmaceutical and cosmeceutical applications. Candida antarctica lipase B (CALB) is quite often used for non-aqueous synthesis, although ...

The Psychology of Isolated and Confined Environments: Understanding Human Behavior in Antarctica.

ERIC Educational Resources Information Center

Palinkas, Lawrence A.

2003-01-01

Reviews lessons learned from research in Antarctica with relevance to understanding human behavior in other isolated and confined environments. Outlines four distinct characteristics of psychosocial adaptation to such environments and discusses some of the benefits for individuals seeking challenging experiences. (Contains references.) (SLD)

Evaluation of solar flares and electron precipitation by nitrate distribution in Antarctica

NASA Astrophysics Data System (ADS)

Dreschhoff, Gisela A.; Zeller, Edward J.

1991-10-01

Most of the time devoted to project research was spent in Antarctica. A firm core was drilled by hand to a depth of 29 meters at Windless Bight on the Ross Ice Shelf. The main result is that all of the major peaks identified as resulting from ionization caused by SPEs that were found in the 1988-89 core could also be identified in the analytical sequence from the 1990-91 core. Following the Antarctic field season, a set of snow samples were obtained that had been collected by the International Trans-Antarctica Expedition. The analysis of these samples showed nitrate flux that correlates closely with known spatial distribution of electron precipitation in the south polar region. A new apparatus has been build for field analysis on a continuous basis of nitrate and conductivity in a melt derived from the vertical melting of ice cores.

Complete Genome and Methylome Analysis of Psychrotrophic Bacterial Isolates from Lake Untersee in Antarctica.

PubMed

Fomenkov, Alexey; Akimov, Vladimir N; Vasilyeva, Lina V; Andersen, Dale T; Vincze, Tamas; Roberts, Richard J

2017-03-16

This paper describes the complete genome sequences and methylome analysis of six psychrotrophic strains isolated from perennially ice-covered Lake Untersee in Antarctica. Copyright © 2017 Fomenkov et al.

Epilithic lichens in the Beacon sandstone formation, Victoria Land, Antarctica

NASA Technical Reports Server (NTRS)

Hale, M. E.; Friedmann, E. I. (Principal Investigator)

1987-01-01

The epilithic lichen flora on the Beacon sandstone formation in Victoria Land consists of seven species: Acarospora gwynnii Dodge & Rudolph, Buellia grisea Dodge & Baker, B. pallida Dodge & Baker, Carbonea capsulata (Dodge & Baker) Hale comb. nov., Lecanora fuscobrunnea Dodge & Baker, Lecidea cancriformis Dodge & Baker, and L. siplei Dodge & Baker. The typification of the species is given along with descriptions and distribution in Antarctica.

The far reach of ice-shelf thinning in Antarctica

NASA Astrophysics Data System (ADS)

Reese, R.; Gudmundsson, G. H.; Levermann, A.; Winkelmann, R.

2018-01-01

Floating ice shelves, which fringe most of Antarctica's coastline, regulate ice flow into the Southern Ocean1-3. Their thinning4-7 or disintegration8,9 can cause upstream acceleration of grounded ice and raise global sea levels. So far the effect has not been quantified in a comprehensive and spatially explicit manner. Here, using a finite-element model, we diagnose the immediate, continent-wide flux response to different spatial patterns of ice-shelf mass loss. We show that highly localized ice-shelf thinning can reach across the entire shelf and accelerate ice flow in regions far from the initial perturbation. As an example, this `tele-buttressing' enhances outflow from Bindschadler Ice Stream in response to thinning near Ross Island more than 900 km away. We further find that the integrated flux response across all grounding lines is highly dependent on the location of imposed changes: the strongest response is caused not only near ice streams and ice rises, but also by thinning, for instance, well-within the Filchner-Ronne and Ross Ice Shelves. The most critical regions in all major ice shelves are often located in regions easily accessible to the intrusion of warm ocean waters10-12, stressing Antarctica's vulnerability to changes in its surrounding ocean.

Algae Reefs in Shark Bay, Western Australia, Australia

NASA Image and Video Library

1990-12-10

STS035-81-040 (2-10 Dec 1990) --- Numerous algae reefs are seen in Shark Bay, Western Australia, Australia (26.0S, 113.5E) especially in the southern portions of the bay. The south end is more saline because tidal flow in and out of the bay is restricted by sediment deposited at the north and central end of the bay opposite the mouth of the Wooramel River. This extremely arid region produces little sediment runoff so that the waters are very clear, saline and rich in algae.

Handbook on Australia.

ERIC Educational Resources Information Center

Texas Education Agency, Austin.

A study unit on Australia for secondary students is divided into eight sections. Section 1 introduces students to the states, territories, and capitals of the country. Section two, land and people, discusses the size, location, geology, climate, flora and fauna, and population of Australia. Sections 3 and 4 outline Australian history and include…

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

NASA Technical Reports Server (NTRS)

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

Data report for the Siple Coast (Antarctica) project

NASA Technical Reports Server (NTRS)

Bindschadler, R. A.; Stephenson, S. N.; Roberts, E. P.; Macayeal, D. R.; Lindstrom, D. R.

1988-01-01

This report presents data collected during three field seasons of glaciological studies in the Antarctica and describes the methods employed. The region investigated covers the mouths of Ice Streams B and C (the Siple Coast) and Crary Ice Rise on the Ross Ice Shelf. Measurements included in the report are as follows: surface velocity and deformation from repeated satellite geoceiver positions; surface topography from optical levelling; radar sounding of ice thickness; accumulation rates; near-surface densities and temperature profiles; and mapping from aerial photography.

Ocean mixing beneath Pine Island Glacier ice shelf, West Antarctica

NASA Astrophysics Data System (ADS)

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.

Accuracy Assessment of Recent Global Ocean Tide Models around Antarctica

NASA Astrophysics Data System (ADS)

Lei, J.; Li, F.; Zhang, S.; Ke, H.; Zhang, Q.; Li, W.

2017-09-01

Due to the coverage limitation of T/P-series altimeters, the lack of bathymetric data under large ice shelves, and the inaccurate definitions of coastlines and grounding lines, the accuracy of ocean tide models around Antarctica is poorer than those in deep oceans. Using tidal measurements from tide gauges, gravimetric data and GPS records, the accuracy of seven state-of-the-art global ocean tide models (DTU10, EOT11a, GOT4.8, FES2012, FES2014, HAMTIDE12, TPXO8) is assessed, as well as the most widely-used conventional model FES2004. Four regions (Antarctic Peninsula region, Amery ice shelf region, Filchner-Ronne ice shelf region and Ross ice shelf region) are separately reported. The standard deviations of eight main constituents between the selected models are large in polar regions, especially under the big ice shelves, suggesting that the uncertainty in these regions remain large. Comparisons with in situ tidal measurements show that the most accurate model is TPXO8, and all models show worst performance in Weddell sea and Filchner-Ronne ice shelf regions. The accuracy of tidal predictions around Antarctica is gradually improving.

Atmospheric Change in Antarctica since the 1957--1958 International Geophysical Year

NASA Astrophysics Data System (ADS)

Nicolas, Julien Pierre

The Antarctic Ice Sheet holds a volume of ice and snow equivalent to 55 meters of sea level. The melting of only a relatively small fraction of this volume could have dramatic consequences for populations around the world. With this in mind, the research presented here focuses on two atmospheric variables that are key controls of the state of the ice sheet: its surface mass balance (or net snowfall) and its near-surface air temperature. The analysis aims to understand how these two parameters have changed (if at all) since the 1957-1958 International Geophysical Year (IGY), the start of the instrumental era in Antarctica. Particular attention is given to the part of the continent known as West Antarctica, the most vulnerable to atmospheric and oceanic warming, and the one where rapid glacial change is currently taking place. The research is divided into three parts. The first part uses a set of seven global reanalyses to investigate the changes in Antarctic surface mass balance and Southern Ocean precipitation since 1979 (start of the reanalyses). This investigation is also intended to shed light on the reliability of these reanalyses, which often contained artifacts caused by changes in the observing system, particularly in high southern latitudes. Spurious changes in precipitation are found to various degrees in all data sets but with varying characteristics and origins. According to the two reanalyses deemed most reliable, neither Antarctic surface mass balance nor Southern Ocean precipitation have changed significantly over the past three decades. The second part consists of a multifaceted investigation of the near-surface temperature record from Byrd Station, in central West Antarctica. As the only meteorological record in this region to extend back to the IGY, it is a critical data set, but also one with a complicated history and substantial data gaps. A comprehensive revision of the record is undertaken and a novel approach is used to estimate the missing

Transcriptome sequencing of the Antarctic vascular plant Deschampsia antarctica Desv. under abiotic stress.

PubMed

Lee, Jungeun; Noh, Eun Kyeung; Choi, Hyung-Seok; Shin, Seung Chul; Park, Hyun; Lee, Hyoungseok

2013-03-01

Antarctic hairgrass (Deschampsia antarctica Desv.) is the only natural grass species in the maritime Antarctic. It has been studied as an extremophile that has successfully adapted to marginal land with the harshest environment for terrestrial plants. However, limited genetic research has focused on this species due to the lack of genomic resources. Here, we present the first de novo assembly of its transcriptome by massive parallel sequencing and its expression profile using D. antarctica grown under various stress conditions. Total sequence reads generated by pyrosequencing were assembled into 60,765 unigenes (28,177 contigs and 32,588 singletons). A total of 29,173 unique protein-coding genes were identified based on sequence similarities to known proteins. The combined results from all three stress conditions indicated differential expression of 3,110 genes. Quantitative reverse transcription polymerase chain reaction showed that several well-known stress-responsive genes encoding late embryogenesis abundant protein, dehydrin 1, and ice recrystallization inhibition protein were induced dramatically and that genes encoding U-box-domain-containing protein, electron transfer flavoprotein-ubiquinone, and F-box-containing protein were induced by abiotic stressors in a manner conserved with other plant species. We identified more than 2,000 simple sequence repeats that can be developed as functional molecular markers. This dataset is the most comprehensive transcriptome resource currently available for D. antarctica and is therefore expected to be an important foundation for future genetic studies of grasses and extremophiles.

Mid-Miocene cooling and the extinction of tundra in continental Antarctica

PubMed Central

Lewis, Adam R.; Marchant, David R.; Ashworth, Allan C.; Hedenäs, Lars; Hemming, Sidney R.; Johnson, Jesse V.; Leng, Melanie J.; Machlus, Malka L.; Newton, Angela E.; Raine, J. Ian; Willenbring, Jane K.; Williams, Mark; Wolfe, Alexander P.

2008-01-01

A major obstacle in understanding the evolution of Cenozoic climate has been the lack of well dated terrestrial evidence from high-latitude, glaciated regions. Here, we report the discovery of exceptionally well preserved fossils of lacustrine and terrestrial organisms from the McMurdo Dry Valleys sector of the Transantarctic Mountains for which we have established a precise radiometric chronology. The fossils, which include diatoms, palynomorphs, mosses, ostracodes, and insects, represent the last vestige of a tundra community that inhabited the mountains before stepped cooling that first brought a full polar climate to Antarctica. Paleoecological analyses, 40Ar/39Ar analyses of associated ash fall, and climate inferences from glaciological modeling together suggest that mean summer temperatures in the region cooled by at least 8°C between 14.07 ± 0.05 Ma and 13.85 ± 0.03 Ma. These results provide novel constraints for the timing and amplitude of middle-Miocene cooling in Antarctica and reveal the ecological legacy of this global climate transition. PMID:18678903

Teaching about Australia. ERIC Digest.

ERIC Educational Resources Information Center

Prior, Warren R.

Many reasons can be offered for teaching about Australia. The field of Australian studies offers many opportunities for U.S. teachers and students to critically analyze aspects of their own culture, for there are many experiences in the history of Australia that parallel the U.S. experience. Australia and the United States have strong ongoing…

A CCD experimental platform for large telescope in Antarctica based on FPGA

NASA Astrophysics Data System (ADS)

Zhu, Yuhua; Qi, Yongjun

2014-07-01

The CCD , as a detector , is one of the important components of astronomical telescopes. For a large telescope in Antarctica, a set of CCD detector system with large size, high sensitivity and low noise is indispensable. Because of the extremely low temperatures and unattended, system maintenance and software and hardware upgrade become hard problems. This paper introduces a general CCD controller experiment platform, using Field programmable gate array FPGA, which is, in fact, a large-scale field reconfigurable array. Taking the advantage of convenience to modify the system, construction of driving circuit, digital signal processing module, network communication interface, control algorithm validation, and remote reconfigurable module may realize. With the concept of integrated hardware and software, the paper discusses the key technology of building scientific CCD system suitable for the special work environment in Antarctica, focusing on the method of remote reconfiguration for controller via network and then offering a feasible hardware and software solution.

Seasonal variation of seismic ambient noise level at King Sejong Station, Antarctica

NASA Astrophysics Data System (ADS)

Lee, W.; Sheen, D.; Seo, K.; Yun, S.

2009-12-01

The generation of the secondary- or double-frequency (DF) microseisms with dominant frequencies between 0.1 and 0.5 Hz has been explained by nonlinear second-order pressure perturbations on the ocean bottom due to the interference of two ocean waves of equal wavelengths traveling in opposite directions. Korea Polar Research Institute (KOPRI) has been operating a broadband seismic station (KSJ1) at King George Island (KGI), Antarctica, since 2001. Examining the ambient seismic noise level for the period from 2006 to 2008 at KSJ1, we found a significant seasonal variation in the frequency range 0.1-0.5 Hz. Correlation of the DF peaks with significant ocean wave height and peak wave period models indicates that the oceanic infragravity waves in the Drake Passage is a possible source to excite the DF microseisms at KGI. Location of King Sejong Station, Antarctica Seasonal variations of DF peak, significant wave height, and peak wave period

Anaerobic Psychrophiles from Lake Zub and Lake Untersee, Antarctica

NASA Technical Reports Server (NTRS)

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

Macroalgae Extracts From Antarctica Have Antimicrobial and Anticancer Potential

PubMed Central

Martins, Rosiane M.; Nedel, Fernanda; Guimarães, Victoria B. S.; da Silva, Adriana F.; Colepicolo, Pio; de Pereira, Claudio M. P.; Lund, Rafael G.

2018-01-01

Background: Macroalgae are sources of bioactive compounds due to the large number of secondary metabolites they synthesize. The Antarctica region is characterized by extreme weather conditions and abundant aggregations of macroalgae. However, current knowledge on their biodiversity and their potential for bio-prospecting is still fledging. This study evaluates the antimicrobial and cytotoxic activity of different extracts of four macroalgae (Cystosphaera jacquinotii, Iridaea cordata, Himantothallus grandifolius, and Pyropia endiviifolia) from the Antarctic region against cancer and non-cancer cell lines. Methods: The antimicrobial activity of macroalgae was evaluated by the broth microdilution method. Extracts were assessed against Staphylococcus aureus ATCC 19095, Enterococcus faecalis ATCC 4083, Escherichia coli ATCC29214, Pseudomonas aeruginosa ATCC 9027, Candida albicans ATCC 62342, and the clinical isolates from the human oral cavity, namely, C. albicans (3), C. parapsilosis, C. glabrata, C. lipolytica, and C. famata. Cytotoxicity against human epidermoid carcinoma (A-431) and mouse embryonic fibroblast (NIH/3T3) cell lines was evaluated with MTT colorimetric assay. Results: An ethyl acetate extract of H. grandifolius showed noticeable antifungal activity against all fungal strains tested, including fluconazole-resistant samples. Cytotoxicity investigation with a cancer cell line revealed that the ethyl acetate extract of I. cordata was highly cytotoxic against A-431 cancer cell line, increasing the inhibitory ratio to 91.1 and 95.6% after 24 and 48 h exposure, respectively, for a concentration of 500 μg mL−1. Most of the algal extracts tested showed little or no cytotoxicity against fibroblasts. Conclusion: Data suggest that macroalgae extracts from Antarctica may represent a source of therapeutic agents. HIGHLIGHTS Different macroalgae samples from Antarctica were collected and the lyophilized biomass of each macroalgae was extracted sequentially with

Antarctica: Teaching and Learning about. A Teacher's Guide.

ERIC Educational Resources Information Center

Kiernan, Jan; Brewer, Warren

In 1980 the members of the Pacific Circle Consortium (Australia, New Zealand, the United States, Japan, and Canada) considered a proposal from the Tasmanian Education Department for a project to develop a curriculum framework and teaching materials about the Antarctic. The outcome was the Antarctic Project conducted jointly by Australia and New…

The Ross Orogen and Lachlan Fold Belt in Marie Byrd Land, Northern Victoria Land and New Zealand: implication for the tectonic setting of the Lachlan Fold Belt in Antarctica

USGS Publications Warehouse

Bradshaw, J.D.

2007-01-01

Correlation of the Cambrian Delamerian Orogen of Australia and Ross Orogen of the Transantarctic Mountains widely accepted but the extension of the adjacent Lachlan Orogen into Antarctica is controversial. Outside the main Ross-Delamerian belt, evidence of this orogeny is preserved at Mt Murphy in Marie Byrd Land and the in Takaka Terrane of New Zealand. In all pre-break- configurations of the SW Pacific, these two areas are far removed from the Ross-Delamerian belt. Evidence from conglomerates in the Takaka Terrane, however, shows that in Late Cambrian times it was adjacent to the Ross Orogen. This indicates major tectonic displacements within Gondwana after the Cambrian and before break-up. The Lachlan Orogen formed in an extensional belt in a supra-subduction zone setting and the Cambrian rocks of Marie Byrd Land and New Zealand are interpreted as parts of a rifted continental ribbon on the outboard side of the Lachlan belt.

Effects of temperature and water availability on light energy utilization in photosynthetic processes of Deschampsia antarctica.

PubMed

Sáez, Patricia L; Rivera, Betsy K; Ramírez, Constanza F; Vallejos, Valentina; Cavieres, Lohengrin A; Corcuera, Luis J; Bravo, León A

2018-03-30

Regional climate change in Antarctica would favor the carbon assimilation of Antarctic vascular plants, because rising temperatures are approaching their photosynthetic optimum (10-19°C). This could be detrimental for photoprotection mechanisms, mainly those associated with thermal dissipation, making plants more susceptible to eventual drought predicted by climate change models. With the purpose to study the effect of temperature and water availability on light energy utilization and putative adjustments in photoprotective mechanisms of Deschampsia antarctica Desv., plants were collected from two Antarctic provenances: King George Island and Lagotellerie Island. Plants were cultivated at 5°, 10° and 16°C under well-watered (WW) and water-deficit (WD, at 35% of the field capacity) conditions. Chlorophyll fluorescence, pigment content, and de-epoxidation state were evaluated. Regardless of provenances, D. antarctica showed similar morphological, biochemical, and functional responses to growth temperature. Higher temperature triggered an increase in photochemical activity (i.e. ETR, and photochemical quenching), and a decrease in thermal dissipation capacity (i.e. lower xanthophyll pool, Chl a/b, and β carotene/neoxanthin ratios). LMA was reduced at higher temperature, and was only affected in plants exposed to WD at 16°C and exhibiting lower ETR and chlorophylls. D. antarctica is adapted to frequent freezing events, which may induce a form of physiological water stress. Photoprotective responses observed under WD contribute to maintain a stable photochemical activity. Thus, it is possible that short-term temperature increases could favor the photochemical activity of this species. However, long-term effects will depend on the magnitude of changes and the plant's ability to adjust to new growth temperature. This article is protected by copyright. All rights reserved.

Insight to forcing of late Quaternary climate change from aeolian dust archives in eastern Australia

NASA Astrophysics Data System (ADS)

McGowan, H. A.; Marx, S.; Soderholm, J.; Denholm, J.; Petherick, L.

2010-12-01

Australia the effect on the hydroclimate is incorporated into the design of water allocation policy and infrastructure, and the management of environmental systems. Comparison with ice core records from Greenland and Antarctica indicate both synchronicity of global climate variability and the impact of forcings originating from the North Hemisphere. These results highlight the potential for adverse impacts on the climate of Australia by disturbance to North Atlantic Ocean circulation. References Marx, S. K., et al. 2005: Provenance of long travelled dust determined with ultra trace element composition: A pilot study with samples from New Zealand glaciers. Earth Surf. Processes Landforms, 30, 699-716. McGowan, H.A., et al. 2008: An ultra-high resolution record of aeolian sedimentation during the late Quaternary from eastern Australia. Palaeogeogr. Palaeoclimatol. Palaeoecol., 265(3-4), 171-181. McGowan, H. A., et al. 2010: Evidence of solar and tropical ocean forcing of hydroclimate cycles in southeastern Australia for the past 6500 years. Geophys. Res. Lett., 37, L10705, doi:10.1029/2010GL042918.

Contact tracing of in-flight measles exposures: lessons from an outbreak investigation and case series, Australia, 2010

PubMed Central

Franklin, Lucinda; Donohue, Steven; Moran, Rodney; Lambert, Stephen; Maloney, Marion; Humphreys, Jan; Rotty, Jessica; Martin, Nicolee; Lyon, Michael; Tran, Thomas; Selvey, Christine

2011-01-01

Objective To describe a 2010 outbreak of nine cases of measles in Australia possibly linked to an index case who travelled on an international flight from South Africa while infectious. Methods Three Australian state health departments, Victoria, Queensland and New South Wales, were responsible for the investigation and management of this outbreak, following Australian public health guidelines. Results An outbreak of measles occurred in Australia after an infectious case arrived on a 12-hour flight from South Africa. Only one of four cases in the first generation exposed to the index case en route was sitting within the two rows recommended for contact tracing in Australian and other guidelines. The remaining four cases in subsequent generations, including two health care workers, were acquired in health care settings. Seven cases were young adults. Delays in diagnosis and notification hampered disease control and contact tracing efforts. Conclusion Review of current contact tracing guidelines following in-flight exposure to an infectious measles case is required. Alternative strategies could include expanding routine contact tracing beyond the two rows on either side of the case’s row or expansion on a case-by-case basis depending on cabin layout and case and contact movements in flight. Releasing information about the incident by press release or providing generic information to everyone on the flight using e-mail or text messaging information obtained from the relevant airline, may also be worthy of consideration. Disease importation, inadequately vaccinated young adults and health care-related transmission remain challenges for measles control in an elimination era. PMID:23908891

It Happened in Antarctica. A Collection of Observations Requiring Scientific Explanations.

ERIC Educational Resources Information Center

Yaxley, Murray

There are many reasons for studying Antarctica. It is the key element in the world's climate. Some of the secrets of the earth's past are locked beneath its icecap. It has a fascinating physical environment and a unique and fragile ecosystem. It is a frontier of scientific research and technological development. Its history is an important and…

Early human occupation of a maritime desert, Barrow Island, North-West Australia

NASA Astrophysics Data System (ADS)

Veth, Peter; Ward, Ingrid; Manne, Tiina; Ulm, Sean; Ditchfield, Kane; Dortch, Joe; Hook, Fiona; Petchey, Fiona; Hogg, Alan; Questiaux, Daniele; Demuro, Martina; Arnold, Lee; Spooner, Nigel; Levchenko, Vladimir; Skippington, Jane; Byrne, Chae; Basgall, Mark; Zeanah, David; Belton, David; Helmholz, Petra; Bajkan, Szilvia; Bailey, Richard; Placzek, Christa; Kendrick, Peter

2017-07-01

Archaeological deposits from Boodie Cave on Barrow Island, northwest Australia, reveal some of the oldest evidence for Aboriginal occupation of Australia, as well as illustrating the early use of marine resources by modern peoples outside of Africa. Barrow Island is a large (202 km2) limestone continental island located on the North-West Shelf of Australia, optimally located to sample past use of both the Pleistocene coastline and extensive arid coastal plains. An interdisciplinary team forming the Barrow Island Archaeology Project (BIAP) has addressed questions focusing on the antiquity of occupation of coastal deserts by hunter-gatherers; the use and distribution of marine resources from the coast to the interior; and the productivity of the marine zone with changing sea levels. Boodie Cave is the largest of 20 stratified deposits identified on Barrow Island with 20 m3 of cultural deposits excavated between 2013 and 2015. In this first major synthesis we focus on the dating and sedimentology of Boodie Cave to establish the framework for ongoing analysis of cultural materials. We present new data on these cultural assemblages - including charcoal, faunal remains and lithics - integrated with micromorphology, sedimentary history and dating by four independent laboratories. First occupation occurs between 51.1 and 46.2 ka, overlapping with the earliest dates for occupation of Australia. Marine resources are incorporated into dietary assemblages by 42.5 ka and continue to be transported to the cave through all periods of occupation, despite fluctuating sea levels and dramatic extensions of the coastal plain. The changing quantities of marine fauna through time reflect the varying distance of the cave from the contemporaneous shoreline. The dietary breadth of both arid zone terrestrial fauna and marine species increases after the Last Glacial Maximum and significantly so by the mid-Holocene. The cave is abandoned by 6.8 ka when the island becomes increasingly distant

Construction, maintenance, and operation of a glacial runway : McMurdo Station, Antarctica

DOT National Transportation Integrated Search

1998-03-01

On February 7, 1994, a C-141 departed Christchurch, New Zealand, and landed on the 3050-m (10,000-ft) Pegasus glacial ice runway, located on the Ross Ice Shelf 13 km (8 mi) south of McMurdo, Antarctica. This event marked the final test for a five-yea...

Book review: The future of Antarctica

USGS Publications Warehouse

Behrendt, John C.

1991-01-01

A conference on Antarctica: an Exploitable Resource too Valuable to Develop? took place at the Sir Robert Menzies Centre for Australian studies at the University of London in either late 1989 or early 1990. The papers were compiled into this small book (only 104 pages of text exclusive of useful appendices containing maps, texts of the Antarctic treaty and the Convention on the regulation of Antarctic Mineral Resource Activity [CRAMRA]) which addresses the hottest issues confronting the Antarctic Treaty Consultative Parties in the early 1990’s. Some of the discussion is being overtaken by events, but fortunately, the general quality and broadness of the coverage will make the book useful to diplomats, historians, international lawyers, scientists and other environmentalists for some time to come.

Late Neogene changes in North America and Antarctica absolute plate motions inferred from the Mid-Atlantic and Southwest Indian Ridges spreading histories

NASA Astrophysics Data System (ADS)

Iaffaldano, Giampiero; DeMets, Charles

2017-04-01

Reconstructions of absolute plate motions underpin our understanding of the plate torque balance, but are challenging due to difficulties in inferring well-dated rates and directions of plate movements from hot spot tracks. Useful information about plate dynamics can be inferred from rapid absolute plate motion changes, as these are linked only to the torque(s) that changed. Here we infer late Neogene changes in the absolute motions of North America and possibly Antarctica from changes in the easier-to-determine relative plate motions recorded along the Arctic, northern Mid-Atlantic and Southwest Indian Ridges. We show that Eurasia/North America and Nubia/North America motions changed by the same amount between 8 and 5 Ma, as may have Nubia/Antarctica and Somalia/Antarctica plate motions. By considering additional, independent constraints on Somalia/India plate motion, we argue that a scenario in which North America and Antarctica absolute motions changed is the simplest one that explains the observed changes in relative motions. We speculate that these changes are linked to the late Neogene dynamics of the Pacific plate.

Late Neogene changes in North America and Antarctica absolute plate motions inferred from the Mid-Atlantic and Southwest Indian Ridges spreading histories

NASA Astrophysics Data System (ADS)

Iaffaldano, G.; DeMets, C.

2016-08-01

Reconstructions of absolute plate motions underpin our understanding of the plate torque balance, but are challenging due to difficulties in inferring well-dated rates and directions of plate movements from hot spot tracks. Useful information about plate dynamics can be inferred from rapid absolute plate motion changes, as these are linked only to the torque(s) that changed. Here we infer late Neogene changes in the absolute motions of North America and possibly Antarctica from changes in the easier-to-determine relative plate motions recorded along the Arctic, northern Mid-Atlantic and Southwest Indian Ridges. We show that Eurasia/North America and Nubia/North America motions changed by the same amount between 8 and 5 Ma, as may have Nubia/Antarctica and Somalia/Antarctica plate motions. By considering additional, independent constraints on Somalia/India plate motion, we argue that a scenario in which North America and Antarctica absolute motions changed is the simplest one that explains the observed changes in relative motions. We speculate that these changes are linked to the late Neogene dynamics of the Pacific plate.

Towards evidence-based health promotion and service provision for new migrants to Australia.

PubMed

Kelaher, M; Williams, G; Manderson, L

1999-11-01

To examine patterns of health utilization and health information dissemination among immigrants to Australia in the first 6 months of immigration using data from the Longitudinal Study of Immigrants to Australia (LSIA). The population for the LSIA consists of 5178 principal applicants making their first arrival to Australia on a migrant visa between 1 September 1993 and 31 August 1995, inclusive, and who are aged 15 years or over at the time (96% of all principal applicants). The influence of immigration category, country of birth, health status and age on the likelihood of receiving information about health, sources of health information and use of general practitioners were explored using separate logistic regressions for men and women. Women who received health information were older and less likely to have a chronic illness than women who did not. Men who received health information were older and more likely to be in the Business visa category. Younger women, those in Preferential Family visa categories and bilingual women were more likely than other women to have received health information from an NGO. For men, the only significant predictor of source of health information was being in the Independent visa category. Women who used health services were younger, more likely to have a chronic illness, be proficient in English and less likely to be in the Independent visa category than women who did not. Men who used health services were older, more likely to have a chronic condition and have limited English than men who did not. Men who used health services were more likely to be in the Humanitarian visa class and less likely to be in the Concessional Family or Business visa categories than men who did not use health services. They were also more likely to have been born in Oceania, Middle East and North Africa and Africa. The results of this study indicate that there are important differentials in knowledge of and use of the health system and these differences

Wood-Destroying Soft Rot Fungi in the Historic Expedition Huts of Antarctica

PubMed Central

Blanchette, Robert A.; Held, Benjamin W.; Jurgens, Joel A.; McNew, Douglas L.; Harrington, Thomas C.; Duncan, Shona M.; Farrell, Roberta L.

2004-01-01

Three expedition huts in the Ross Sea region of Antarctica, built between 1901 and 1911 by Robert F. Scott and Ernest Shackleton, sheltered and stored the supplies for up to 48 men for 3 years during their explorations and scientific investigation in the South Pole region. The huts, built with wood taken to Antarctica by the early explorers, have deteriorated over the past decades. Although Antarctica has one of the coldest and driest environments on earth, microbes have colonized the wood and limited decay has occurred. Some wood in contact with the ground contained distinct microscopic cavities within secondary cell walls caused by soft rot fungi. Cadophora spp. could be cultured from decayed wood and other woods sampled from the huts and artifacts and were commonly associated with the soft rot attack. By using internal transcribed spacer sequences of ribosomal DNA and morphological characteristics, several species of Cadophora were identified, including C. malorum, C. luteo-olivacea, and C. fastigiata. Several previously undescribed Cadophora spp. also were found. At the Cape Evans and Cape Royds huts, Cadophora spp. commonly were isolated from wood in contact with the ground but were not always associated with soft rot decay. Pure cultures of Cadophora used in laboratory decay studies caused dark staining of all woods tested and extensive soft rot in Betula and Populus wood. The presence of Cadophora species, but only limited decay, suggests there is no immediate threat to the structural integrity of the huts. These fungi, however, are widely found in wood from the historic huts and have the capacity to cause extensive soft rot if conditions that are more conducive to decay become common. PMID:15006750

Magnetic anomalies in East Antarctica: a window on major tectonic provinces and their boundaries

USGS Publications Warehouse

Golynsky, A.V.

2007-01-01

An analysis of aeromagnetic data compiled within the Antarctic Digital Magnetic Anomaly Project (ADMAP) yields significant new insight into major tectonic provinces of East Antarctica. Several previously unknown crustal blocks are imaged in the deep interior of the continent, which are interpreted as cratonic nuclei. These cratons are fringed by a large and continuous orogenic belt between Coats Land and Princess Elizabeth Land, with possible branches in the deeper interior of East Antarctica. Most of the crustal provinces and boundaries identified in this study are only in part exposed. More detailed analyses of these crustal provinces and their tectonic boundaries would require systematic acquisition of additional high-resolution magnetic data, because at present the ADMAP database is largely inadequate to address many remaining questions regarding Antarctica’s tectonic evolution.

Measurement Of Solar Radiation at New Delhi, High Altitude Observatory, Hanle and Maitri Antarctica

NASA Astrophysics Data System (ADS)

Jain, S. L.; Arya, B. C.

The measurement of solar radiation plays an important role in climate and environmental change studies. The enhanced UV-B radiations at the ground level has the potential to cause adverse biological and environmental impacts. The amount of UV-B radiation at ground level depends on various temporal, spatial and meteorological factors such as time of the day, season, altitude, clouds, surface albedo, ozone, aerosols, etc. The risks for the human health, plant, animals and material are growing because of high exposition of the solar radiation which is caused by ozone depletion and other anthropogenic activities. A limited measurements have been made at high altitudes and Antarctica which are very crucial to inhabitants of these locations. In view of the above, measurements of solar radiation along with other parameters were carried out at Leh (34°77' N, 77°36' E), 3311 meter above mean sea level as well as at Indian Astronomical Observatory , Leh / Hanle ( Indian Institute of Astrophysics, Bangalore), Hanle (Mount Saraswati), Jammu and Kashmir (India) (32°43' N, 77°34' E), 4467 meter above mean sea level during July 13-31, 1999, June 2000 and July 2003 in a campaign mode. These measurements are first of its kind at a unique location well deep inside the troposphere as it happens to be one of the highest observatory in the world. The regular measurements are also being carried out at NPL, New Delhi(280 65^' N, 770 21^' E) and Maitri, Antarctica(70.440 S, 11.450 E). Also the data were collected during our voyage to Antarctica to cover latitudinal distribution of these parameters from Goa, India (15.240 N, 73.420 E) to Maitri, Antarctica (70.440 S, 11.450 E) using a highly sophisticated and microprocessor based compact hand held sun photometer consisting of five filter channels at 300, 305, 312, 940 and 1020 nm to measure solar radiation at all the sites. The measurements were used to derive total column ozone, water vapour and aerosol optical depth etc. The solar

Opening a new window on the southern stars for less money: PAIX the first Antarctica polar mission photometer

NASA Astrophysics Data System (ADS)

Chadid, Merieme; Vernin, Jean; Abe, Lyu; Agabi, Karim; Jumper, George; Preston, George W.; Sneden, Chris; Liu, Liyong; Yao, Yongqiang; Wang, H.-S.; Aristidi, Éric; Rivet, J.-P.; Carbillet, Marcel; Giordano, Ch.; Bondoux, E.; Moggio, L.; Trinquet, H.

2016-08-01

In this invited paper, we implement a new way to study the stellar oscillations, pulsations and their evolutionary properties with long uninterrupted and continuous precision observations over 150 days from the ground, and without the regular interruptions imposed by the earth rotation. PAIX-First Robotic Antarctica Polar Mission- gives a new insight to cope with unresolved stellar enigma and stellar oscillation challenges and offers a great opportunity to benefit from an access to the best astronomical site on Earth -DomeC-. The project is made of low cost commercial components, and achieves astrophysical measurement time-series of stellar physics fields, challenging photometry from space that shows large gaps in terms of flexibility during the observing runs, the choice of targets, the repair of failures and the inexorable high costs. PAIX has yet more advantages than space missions in observing in UBV RI bands and then collecting unprecedented simultaneous multicolor light curves of several targets. We give a brief history of the Astronomy in Antarctica and describe the first polar robotized mission PAIX and the outcome of stellar physics from the heart of Antarctica during several polar nights. We briefly discuss our first results and perspectives on the pulsating stars and its evolution from Antarctica, especially the connection between temporal hydrodynamic phenomena and cyclic modulations. Finally, we highlight the impact of PAIX on the stellar physics study and the remaining challenges to successfully accomplish the Universe explorations under extreme conditions.

Improved estimate of accelerated Antarctica ice mass loses from GRACE, Altimetry and surface mass balance from regional climate model output

NASA Astrophysics Data System (ADS)

Velicogna, I.; Sutterley, T. C.; A, G.; van den Broeke, M. R.; Ivins, E. R.

2016-12-01

We use Gravity Recovery and Climate Experiment (GRACE) monthly gravity fields to determine the regional acceleration in ice mass loss in Antarctica for 2002-2016. We find that the total mass loss is controlled by only a few regions. In Antarctica, the Amundsen Sea (AS) sector and the Antarctic Peninsula account for 65% and 18%, respectively, of the total loss (186 ± 10 Gt/yr) mainly from ice dynamics. The AS sector contributes most of the acceleration in loss (9 ± 1 Gt/yr2 ), and Queen Maud Land, East Antarctica, is the only sector with a significant mass gain due to a local increase in SMB (57 ± 5 Gt/yr). We compare GRACE regional mass balance estimates with independent estimates from ICESat-1 and Operation IceBridge laser altimetry, CryoSat-2 radar altimetry, and surface mass balance outputs from RACMO2.3. In the Amundsen Sea Embayment of West Antarctica, an area experiencing rapid retreat and mass loss to the sea, we find good agreement between GRACE and altimetry estimates. Comparison of GRACE with these independent techniques in East Antarctic shows that GIA estimates from the new regional ice deglaciation models underestimate the GIA correction in the EAIS interior, which implies larger losses of the Antarctica ice sheet by about 70 Gt/yr. Sectors where we are observing the largest losses are closest to warm circumpolar water, and with polar constriction of the westerlies enhanced by climate warming, we expect these sectors to contribute more and more to sea level as the ice shelves that protect these glaciers will melt faster in contact with more heat from the surrounding oc

Coastal-change and glaciological map of the Saunders Coast area, Antarctica: 1972-97

USGS Publications Warehouse

Ferrigno, J.G.; Williams, R.S.; Foley, K.M.

2005-01-01

Satellite images from 1972 to 1997 have been used to prepare a map showing glaciological features of the Saunders Coast area, Antarctica. Analysis of the imagery shows a trend toward ice-front retreat that may be a result of changing environmental conditions.

Diversity and bioprospection of fungal community present in oligotrophic soil of continental Antarctica

USDA-ARS?s Scientific Manuscript database

The diversity of fungal communities from different substrates in Antarctica were studied and their capability to produce bioactive compounds. A one hundred and one fungal isolates were identified by molecular analysis in 35 different fungal taxa from 20 genera. Pseudogymnoascus sp. 3, Pseudogymnoasc...

Macrofossil evidence for a rapid and severe Cretaceous-Paleogene mass extinction in Antarctica.

PubMed

Witts, James D; Whittle, Rowan J; Wignall, Paul B; Crame, J Alistair; Francis, Jane E; Newton, Robert J; Bowman, Vanessa C

2016-05-26

Debate continues about the nature of the Cretaceous-Paleogene (K-Pg) mass extinction event. An abrupt crisis triggered by a bolide impact contrasts with ideas of a more gradual extinction involving flood volcanism or climatic changes. Evidence from high latitudes has also been used to suggest that the severity of the extinction decreased from low latitudes towards the poles. Here we present a record of the K-Pg extinction based on extensive assemblages of marine macrofossils (primarily new data from benthic molluscs) from a highly expanded Cretaceous-Paleogene succession: the López de Bertodano Formation of Seymour Island, Antarctica. We show that the extinction was rapid and severe in Antarctica, with no significant biotic decline during the latest Cretaceous, contrary to previous studies. These data are consistent with a catastrophic driver for the extinction, such as bolide impact, rather than a significant contribution from Deccan Traps volcanism during the late Maastrichtian.

Macrofossil evidence for a rapid and severe Cretaceous-Paleogene mass extinction in Antarctica

NASA Astrophysics Data System (ADS)

Witts, James D.; Whittle, Rowan J.; Wignall, Paul B.; Crame, J. Alistair; Francis, Jane E.; Newton, Robert J.; Bowman, Vanessa C.

2016-05-01

Debate continues about the nature of the Cretaceous-Paleogene (K-Pg) mass extinction event. An abrupt crisis triggered by a bolide impact contrasts with ideas of a more gradual extinction involving flood volcanism or climatic changes. Evidence from high latitudes has also been used to suggest that the severity of the extinction decreased from low latitudes towards the poles. Here we present a record of the K-Pg extinction based on extensive assemblages of marine macrofossils (primarily new data from benthic molluscs) from a highly expanded Cretaceous-Paleogene succession: the López de Bertodano Formation of Seymour Island, Antarctica. We show that the extinction was rapid and severe in Antarctica, with no significant biotic decline during the latest Cretaceous, contrary to previous studies. These data are consistent with a catastrophic driver for the extinction, such as bolide impact, rather than a significant contribution from Deccan Traps volcanism during the late Maastrichtian.

U.S. Geological Survey scientific activities in the exploration of Antarctica: 1946-2006 record of personnel in Antarctica and their postal cachets: U.S. Navy (1946-48, 1954-60), International Geophysical Year (1957-58), and USGS (1960-2006)

USGS Publications Warehouse

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

2007-01-01

Antarctica, a vast region encompassing 13.2 million km2 (5.1 million mi2), is considered to be one of the most important scientific laboratories on Earth. During the past 60 years, the USGS, in collaboration and with logistical support from the National Science Foundation's Office of Polar Programs, has sent 325 USGS scientists to Antarctica to work on a wide range of projects: 169 personnel from the NMD (mostly aerial photography, surveying, and geodesy, primarily used for the modern mapping of Antarctica), 138 personnel from the GD (mostly geophysical and geological studies onshore and offshore), 15 personnel from the WRD (mostly hydrological/glaciological studies in the McMurdo Dry Valleys), 2 personnel from the BRD (microbiological studies in the McMurdo Dry Valleys), and 1 person from the Director's Office (P. Patrick Leahy, Acting Director, 2005–06 austral field season). Three GD scientists and three NMD scientists have carried out field work in Antarctica 9 or more times: John C. Behrendt (15), who started in 1956–57 and published two memoirs (Behrendt, 1998, 2005), Arthur B. Ford (10), who started in 1960–61, and Gary D. Clow (9), who started in 1985–86; Larry D. Hothem (12), who began as a winter-over geodesist at Mawson Station in 1968–69, and Jerry L. Mullins (12), who started in 1982–83 and followed in the legendary footsteps of his NMD predecessor, William R. MacDonald (9), who started in 1960–61 and supervised the acquisition of more than 1,000,000 square miles of aerial photography of Antarctica. This report provides a record as complete as possible, of USGS and non-USGS collaborating personnel in Antarctica from 1946–2006, the geographic locations of their work, and their scientific/engineering disciplines represented. Postal cachets for each year follow the table of personnel and scientific activities in the exploration of Antarctica during those 60 years. To commemorate special events and projects in Antarctica, it became an

Trace metals in Antarctica related to climate change and increasing human impact.

PubMed

Bargagli, R

2000-01-01

Metals are natural constituents of the abiotic and biotic components of all ecosystems, and under natural conditions they are cycled within and between the geochemical spheres--the atmosphere, lithosphere, hydrosphere, and biosphere--at quite steady fluxes. In the second half of the twentieth century, the huge increase in energy and mineral consumption determined anthropogenic emissions of several metals exceeding those from natural sources, e.g., volcanoes and windborne soil particles. In the Northern Hemisphere, the biogeochemical cycles of Pb, Cd, Zn, Cu, and other metals were significantly altered, even in Arctic regions. On the contrary, available data on trace metal concentrations in abiotic matrices from continental Antarctica, summarized in this review, suggest that the biogeochemical cycle of Pb is probably the only one that has been significantly altered by anthropogenic emissions in Antarctica and elsewhere in the Southern Hemisphere, especially in the period 1950-1975. Environmental contamination by other metals from anthropogenic sources in Antarctica itself can generally only be detected in snow samples taken within a range of a few kilometers or several hundred meters from scientific stations. Local metal pollution from human activities in Antarctica may compromise studies aimed at assessing the biogeochemical cycle of trace elements and the effects of global climate change. Thus, this review focuses on concentrations of metals in atmospheric particulate, snow, surface soils, and freshwater from the Antarctic continent and surface sediments and seawater from the Southern Ocean, which can plausibly be regarded as global background values of trace elements. These baselines are also necessary in view of the construction of new stations, the expansion of existing facilities to support research, and the growth of tourism and fisheries. Despite difficulties in making comparisons with data from other remote areas of the world, concentrations of trace metals

Airborne gravimetry for geoid, geopotential models and GOCE - Himalaya and Antarctica cases (Invited)

NASA Astrophysics Data System (ADS)

Forsberg, R.; Olesen, A. V.

2013-12-01

DTU-Space has since many years carried out large area airborne surveys over both polar, tropical and temperate regions, especially for geoid determination and global geopotential models. Recently we have started flying two gravimeters (LCR and Chekan-AM) side by side for increased reliability and redundancy. Typical gravity results are at the 2 mGal rms level, translating into 5-10 cm accuracy in geoid. However, in rough mountainous areas results can be more noisy, mainly due to long-period mountain waves and turbulence. In the paper we outline results of recent challenging campaigns in Nepal (2010) and Antarctica (Antarctic Peninsula and East Antarctica, 2010-13). The latest Antarctic campaign 2012/13, carried out in cooperation with the British Antarctic Survey, Norwegian Polar Institute, and the Argentine Antarctic Institute, involved air drops of fuel to a remote field camp in the Recovery Lakes region, one of the least explored region of deep interior Antarctica. The airborne data collected are validated by cross-over comparisons and comparisons to independent data (IceBridge), and serve at the same time as an independent validation of GOCE satellite gravity data, confirming the satellite data to contain information at half-wavelengths down to 80 km. With no bias between the airborne data and GOCE, airborne gravimetry is perfectly suited to cover the GOCE data gap south of 83 S. We recommend an international, coordinated airborne gravity effort should be carried out over the south polar gap as soon as possible, to ensure a uniform global accuracy of GOCE heritage future geopotential models.

ET nursing education in Australia.

PubMed

Thompson, J M; English, E

1996-05-01

Australia is comparable in size to the United States, but its population is far smaller, approximately 17 million. Australia is technologically advanced and has a high standard of health care, in which ET nursing has always been considered a specialist nursing role. Although Australia is historically linked with England, formation of closer ties with geographic neighbors, such as Southeast Asia, New Zealand, and the Pacific nations, is ongoing. This article describes some relevant aspects of the Australian context and considers the past, present, and expected future trends for ET nurse education in Australia, from the first program in 1971 to current World Council of Enterostomal Therapy-recognized programs teaching students from as far away as Japan, Israel, Singapore, Malaysia, New Zealand, China, Russia, and New Guinea. The content of the programs has progressively broadened in recognition of the expanded scope of practice, and this trend will undoubtedly continue. ET nursing should remain, however, a distinct nursing specialty practice in Australia.

MOBILESAT: Australia's own

NASA Technical Reports Server (NTRS)

Wagg, Michael

1990-01-01

Australia will be introducing a dedicated Mobile Satellite Communications System following the launch of the AUSSAT-B satellites late in 1991. The Mobile Satellite System, MOBILESAT, will provide circuit switched voice/data services and packet-switched data services for land, aeronautical and maritime users. Here, an overview is given of the development program being undertaken within Australia to enable a fully commercial service to be introduced in 1992.

A big blank white canvas? Mapping and modeling human impact in Antarctica

Treesearch

Steve Carver; Tina Tin

2015-01-01

Antarctica is certainly what most people would consider being the world's last great wilderness; largely untouched and undeveloped by humans. Yet it is not inviolate - there are scientific bases, tourist operations, expeditions, airstrips and even roads. Although these impacts are by and large limited in extent, their very presence in an otherwise "blank...

From Beacon Valley, Antarctica to Mars: Bringing the PolarTREC Teacher Research Experience to the Classroom

NASA Astrophysics Data System (ADS)

Hams, J. E.; Marchant, D. R.

2009-12-01

PolarTREC is an educational research experience in which K-14 teachers participate in polar research with scientists as a pathway to improving science education. The program is funded by the National Science Foundation and managed by the Arctic Research Consortium of the United States. Teachers share their experiences with scientists, educators, communities, and students around the world during the expeditions through online journals, and translate the experience to the classroom by developing curricula based on the research expedition. A 2008 PolarTREC teacher research experience involved drilling through buried ice beneath glaciers in one of the Dry Valleys located in the cold-polar desert region of Antarctica. PolarTREC teacher Jacquelyn Hams accompanied Boston University researchers Dr. David Marchant and Sean Mackay to Beacon Valley, Antarctica. Beacon Valley is significant because the ice beneath it is estimated to be over several million years in age, making it the oldest ice known on this planet and it is one of the most Mars-like climatic environments and landscapes on Earth. In order to translate this unique environment to the classroom, lesson plans were created for students to study the topography, glacial landforms, and wind patterns of Beacon Valley. Students also examine the same imagery that scientists use to study the processes that operate in the extreme environments of Antarctica and Mars. The topographic maps and aerial images of Beacon Valley were obtained from the NASA LIMA (Landsat Image Mosaic of Antarctica) website and Mars imagery was obtained from the University of Arizona HiRISE (Hi Resolution Imaging Science Experiment) website. Wind data was downloaded from an anemometer in Beacon Valley and provided courtesy of Sean Mackay of Boston University. The lesson plans are available through the PolarTREC website or by contacting Jacquelyn Hams at hamsje@lavc.edu.

Hervey virus: Study on co-circulation with Henipaviruses in Pteropid bats within their distribution range from Australia to Africa.

PubMed

Kohl, Claudia; Tachedjian, Mary; Todd, Shawn; Monaghan, Paul; Boyd, Victoria; Marsh, Glenn A; Crameri, Gary; Field, Hume; Kurth, Andreas; Smith, Ina; Wang, Lin-Fa

2018-01-01

In 2011, an unusually large number of independent Hendra virus outbreaks were recorded on horse properties in Queensland and New South Wales, Australia. Urine from bat colonies adjacent to the outbreak sites were sampled and screened for Hendra and other viruses. Several novel paramyxoviruses were also isolated at different locations. Here one of the novel viruses, named Hervey virus (HerPV), is fully characterized by genome sequencing, annotation, phylogeny and in vitro host range, and its serological cross-reactivity and neutralization patterns are examined. HerPV may have ecological and spatial and temporal patterns similar to Hendra virus and could serve as a sentinel virus for the surveillance of this highly pathogenic virus. The suitability of HerPV as potential sentinel virus is further assessed by determining the serological prevalence of HerPV antibodies in fruit-eating bats from Australia, Indonesia, Papua New Guinea, Tanzania and the Gulf of Guinea, indicating the presence of similar viruses in regions beyond the Australian border.

The infauna of three widely distributed sponge species (Hexactinellida and Demospongiae) from the deep Ekström Shelf in the Weddell Sea, Antarctica

NASA Astrophysics Data System (ADS)

Kersken, Daniel; Göcke, Christian; Brandt, Angelika; Lejzerowicz, Franck; Schwabe, Enrico; Anna Seefeldt, Meike; Veit-Köhler, Gritta; Janussen, Dorte

2014-10-01

Due to their high abundance and large body size sponges have a central position in Antarctic zoobenthos, where they form the most extensive sponge grounds of the world. Though research on Antarctic benthos communities is quite established, research on sponge-associated infauna communities is scarce. We analyzed associated infauna of fifteen individuals of the sponge species Mycale (Oxymycale) acerata Kirkpatrick, 1907 (Demospongiae: Mycalina), Rossella antarctica Carter, 1872 and R. racovitzae Topsent, 1901 (both Hexactinellida: Lyssacinosida). Samples were collected from the deep Ekström Shelf at 602 m in the South-Eastern Weddell Sea, Antarctica, during the ANT XXIV-2 (SYSTCO I) expedition of RV Polarstern. The number of species, α- and β-diversity and the significantly different species composition of infauna communities related to sponge species were calculated, the latter via cluster analysis. The sponge-associated infauna consisted of five phyla: Foraminifera, Nematoda, Polychaeta, Mollusca and Arthropoda. In total 11,463 infaunal specimens were extracted and we found at least 76 associated species. Highest values of α-diversity were calculated for a sample of R. antarctica with a Shannon-Index of 1.84 and Simpson-Index of 0.72 respectively. Our results of the cluster-analysis show significant differences between infauna communities and a unique species composition for single sponge species. Polychaetes of the genus Syllis Lamarck, 1818 were numerous in M. acerata and genera like Pionosyllis Malmgren, 1867 and Cirratulus Lamarck, 1801 were numerous in R. antarctica. Individuals of the amphipod species Seba cf. dubia Schellenberg, 1926 were often found in R. antarctica and R. racovitzae while Colomastix fissilingua Schellenberg, 1926 was frequent in samples of M. acerata. Molluscs were present in M. acerata and R. antarctica but absent in R. racovitzae.

Estimating Past Temperature Change in Antarctica Based on Ice Core Stable Water Isotope Diffusion

NASA Astrophysics Data System (ADS)

Kahle, E. C.; Markle, B. R.; Holme, C.; Jones, T. R.; Steig, E. J.

2017-12-01

The magnitude of the last glacial-interglacial transition is a key target for constraining climate sensitivity on long timescales. Ice core proxy records and general circulation models (GCMs) both provide insight on the magnitude of climate change through the last glacial-interglacial transition, but appear to provide different answers. In particular, the magnitude of the glacial-interglacial temperature change reconstructed from East Antarctic ice-core water-isotope records is greater ( 9 degrees C) than that from most GCM simulations ( 6 degrees C). A possible source of this difference is error in the linear-scaling of water isotopes to temperature. We employ a novel, nonlinear temperature-reconstruction technique using the physics of water-isotope diffusion to infer past temperature. Based on new, ice-core data from the South Pole, this diffusion technique suggests East Antarctic temperature change was smaller than previously thought. We are able to confirm this result using a simple, water-isotope fractionation model to nonlinearly reconstruct temperature change at ice core locations across Antarctica based on combined oxygen and hydrogen isotope ratios. Both methods produce a temperature change of 6 degrees C for South Pole, agreeing with GCM results for East Antarctica. Furthermore, both produce much larger changes in West Antarctica, also in agreement with GCM results and independent borehole thermometry. These results support the fidelity of GCMs in simulating last glacial maximum climate, and contradict the idea, based on previous work, that the climate sensitivity of current GCMs is too low.

Global Plate Velocities from the Global Positioning System

NASA Technical Reports Server (NTRS)

Larson, Kristine M.; Freymueller, Jeffrey T.; Philipsen, Steven

1997-01-01

We have analyzed 204 days of Global Positioning System (GPS) data from the global GPS network spanning January 1991 through March 1996. On the basis of these GPS coordinate solutions, we have estimated velocities for 38 sites, mostly located on the interiors of the Africa, Antarctica, Australia, Eurasia, Nazca, North America, Pacific, and South America plates. The uncertainties of the horizontal velocity components range from 1.2 to 5.0 mm/yr. With the exception of sites on the Pacific and Nazca plates, the GPS velocities agree with absolute plate model predictions within 95% confidence. For most of the sites in North America, Antarctica, and Eurasia, the agreement is better than 2 mm/yr. We find no persuasive evidence for significant vertical motions (less than 3 standard deviations), except at four sites. Three of these four were sites constrained to geodetic reference frame velocities. The GPS velocities were then used to estimate angular velocities for eight tectonic plates. Absolute angular velocities derived from the GPS data agree with the no net rotation (NNR) NUVEL-1A model within 95% confidence except for the Pacific plate. Our pole of rotation for the Pacific plate lies 11.5 deg west of the NNR NUVEL-1A pole, with an angular speed 10% faster. Our relative angular velocities agree with NUVEL-1A except for some involving the Pacific plate. While our Pacific-North America angular velocity differs significantly from NUVEL-1A, our model and NUVEL-1A predict very small differences in relative motion along the Pacific-North America plate boundary itself. Our Pacific-Australia and Pacific- Eurasia angular velocities are significantly faster than NUVEL-1A, predicting more rapid convergence at these two plate boundaries. Along the East Pacific Pise, our Pacific-Nazca angular velocity agrees in both rate and azimuth with NUVFL-1A.

Australian shelf sediments reveal shifts in Miocene Southern Hemisphere westerlies

PubMed Central

Groeneveld, Jeroen; Henderiks, Jorijntje; Renema, Willem; McHugh, Cecilia M.; De Vleeschouwer, David; Christensen, Beth A.; Fulthorpe, Craig S.; Reuning, Lars; Gallagher, Stephen J.; Bogus, Kara; Auer, Gerald; Ishiwa, Takeshige

2017-01-01

Global climate underwent a major reorganization when the Antarctic ice sheet expanded ~14 million years ago (Ma) (1). This event affected global atmospheric circulation, including the strength and position of the westerlies and the Intertropical Convergence Zone (ITCZ), and, therefore, precipitation patterns (2–5). We present new shallow-marine sediment records from the continental shelf of Australia (International Ocean Discovery Program Sites U1459 and U1464) providing the first empirical evidence linking high-latitude cooling around Antarctica to climate change in the (sub)tropics during the Miocene. We show that Western Australia was arid during most of the Middle Miocene. Southwest Australia became wetter during the Late Miocene, creating a climate gradient with the arid interior, whereas northwest Australia remained arid throughout. Precipitation and river runoff in southwest Australia gradually increased from 12 to 8 Ma, which we relate to a northward migration or intensification of the westerlies possibly due to increased sea ice in the Southern Ocean (5). Abrupt aridification indicates that the westerlies shifted back to a position south of Australia after 8 Ma. Our midlatitude Southern Hemisphere data are consistent with the inference that expansion of sea ice around Antarctica resulted in a northward movement of the westerlies. In turn, this may have pushed tropical atmospheric circulation and the ITCZ northward, shifting the main precipitation belt over large parts of Southeast Asia (4). PMID:28508066

Application of a quantitative histological health index for Antarctic rock cod (Trematomus bernacchii) from Davis Station, East Antarctica.

PubMed

Corbett, Patricia A; King, Catherine K; Mondon, Julie A

2015-08-01

A quantitative Histological Health Index (HHI) was applied to Antarctic rock cod (Trematomus bernacchii) using gill, liver, spleen, kidney and gonad to assess the impact of wastewater effluent from Davis Station, East Antarctica. A total of 120 fish were collected from 6 sites in the Prydz Bay region of East Antarctica at varying distances from the wastewater outfall. The HHI revealed a greater severity of alteration in fish at the wastewater outfall, which decreased stepwise with distance. Gill and liver displayed the greatest severity of alteration in fish occurring in close proximity to the wastewater outfall, showing severe and pronounced alteration respectively. Findings of the HHI add to a growing weight of evidence indicating that the current level of wastewater treatment at Davis Station is insufficient to prevent impact to the surrounding environment. The HHI for T. bernacchii developed in this study is recommended as a useful risk assessment tool for assessing in situ, sub-lethal impacts from station-derived contamination in coastal regions throughout Antarctica. Copyright © 2015 Elsevier Ltd. All rights reserved.

The Potential for Astronomy in Antarctica

NASA Astrophysics Data System (ADS)

Burton, Michael G.

The extremely dry cold and tenuous air of the Antarctic plateau makes it the premier site on the earth for a wide range of astronomical observations especially at infrared and millimetre wavelengths. Background sky emission is one to two order of magnitudes less in intensity and new windows in the atmosphere are opened for viewing through. The high geomagnetic latitudes also make it particularly suitable for measurement of cosmic ray fluxes especially at low energy. The vast quantities of pure transparent ice provide for unparalled conditions for the measurement of neutrino fluxes. This talk will overview the potential of Antarctica for a wide range of astronomical observations conditions that surpass any other ground- based location in most circumstances. It will be an introductory lecture to the field designed for the non-specialist in Antarctic astronomy.

Geological setting of the Concordia Trench-Lake system in East Antarctica

NASA Astrophysics Data System (ADS)

Cianfarra, P.; Forieri, A.; Salvini, F.; Tabacco, I. E.; Zirizotti, A.

2009-06-01

This study presents the interpretation of radio echo-sounding (RES) data collected during the 2003 geophysical campaign of PNRA (Italian National Research Project in Antarctica), which focused on the exploration of the Concordia Trench-Lake system in East Antarctica. The data allow us to identify a new lake (ITL-28) at the southern edge of the Concordia Trench and a series of N-S trending subglacial troughs cutting through the Belgica Highlands. We have mapped the bedrock morphology at 3 km resolution, which led to an improved geographical and geomorphological characterization of the Concordia Trench, Concordia Ridge, Concordia Lake and South Hills. Improved knowledge of the Concordia Trench allowed us to model the 3-D geometry of the Concordia fault, suggesting that it played a role in governing the morpho-tectonic evolution of the bedrock in the Dome C region, and to propose a Cenozoic age for its activity. We recognize the importance of catchment basin morphology in hosting subglacial lakes, and discuss the role played by tectonics, glacial scouring and volcanism in the origin of the trench lakes, basin lakes and relief lakes, respectively.

Durophagous Predation by King Crabs on the Continental Slope off Antarctica

NASA Astrophysics Data System (ADS)

Smith, K.; Aronson, R. B.; Steffel, B. V.; McClintock, J. B.; Amsler, M.; Thatje, S.

2016-02-01

For perhaps tens of millions of years, marine communities in Antarctica have been essentially devoid of durophagous (shell-crushing) predators, which have been excluded by low temperatures. In their absence, the resident species have evolved in isolation and are slow-moving with limited defenses. Rapidly rising sea temperatures around Antarctica are now relaxing the cold-thermal barrier and appear to be allowing deep-water king crabs (Lithodidae) to move up the continental slope, into shallower water. Their potential to emerge on the continental shelf could drastically restructure the endemic communities that live there; in other areas of the world, lithodids are typically generalist predators of invertebrates. Their diet in Antarctic waters remains unknown and it has been speculated that they are opportunistic scavengers. We report the findings of a trapping study conducted in deep water off the western Antarctic Peninsula in 2015. Stomach contents were analyzed for 18 adult Paralomis birsteini trapped on the continental slope. P. birsteini feed primarily on invertebrates such as echinoderms, gastropods and polychaetes. By understanding the prey species targeted by slope-dwelling lithodids, we can begin to project the future impact of an expansion of king crabs onto the Antarctic continental shelf.

On site remediation of a fuel spill and soil reuse in Antarctica.

PubMed

McWatters, R S; Wilkins, D; Spedding, T; Hince, G; Raymond, B; Lagerewskij, G; Terry, D; Wise, L; Snape, I

2016-11-15

The first large-scale remediation of fuel contamination in Antarctica treated 10000L of diesel dispersed in 1700t of soil, and demonstrated the efficacy of on-site bioremediation. The project progressed through initial site assessment and natural attenuation, passive groundwater management, then active remediation and the managed reuse of soil. Monitoring natural attenuation for the first 12years showed contaminant levels in surface soil remained elevated, averaging 5000mg/kg. By contrast, in five years of active remediation (excavation and biopile treatment) contaminant levels decreased by a factor of four. Chemical indicators showed hydrocarbon loss was apportioned to both biodegradation and evaporative processes. Hydrocarbon degradation rates were assessed against biopile soil temperatures, showing a phase of rapid degradation (first 100days above soil temperature threshold of 0°C) followed by slower degradation (beyond 100days above threshold). The biopiles operated successfully within constraints typical of harsh climates and remote sites, including limitations on resources, no external energy inputs and short field seasons. Non-native microorganisms (e.g. inoculations) and other organic materials (e.g. bulking agents) are prohibited in Antarctica making this cold region more challenging for remediation than the Arctic. Biopile operations included an initial fertiliser application, biannual mechanical turning of the soil and minimal leachate recirculation. The biopiles are a practical approach to remediate large quantities of contaminated soil in the Antarctic and already 370t have been reused in a building foundation. The findings presented demonstrate that bioremediation is a viable strategy for Antarctica and other cold regions. Operators can potentially use the modelled relationship between days above 0°C (threshold temperature) and the change in degradation rates to estimate how long it would take to remediate other sites using the biopile technology

Coastal-change and glaciological map of the Bakutis Coast, Antarctica: 1972-2002

USGS Publications Warehouse

Swithinbank, Charles; Williams, Richard S.; Ferrigno, Jane G.; Foley, Kevin M.; Rosanova, Christine E.

2003-01-01

Changes in the area and volume of the polar ice sheets are intricately linked to changes in global climate, and the resulting changes in sea level may severely impact the densely populated coastal regions on Earth. Loss of the West Antarctic part of the Antarctic ice sheet alone could cause a sea-level rise of approximately 6 m. The potential sea-level rise after melting of the entire Antarctic ice sheet is estimated to be 65 m to 73 m. In spite of its importance, the mass balance (the net volumetric gain or loss) of the Antarctic ice sheet is poorly known; it is not known whether the ice sheet is growing or shrinking. As a result, measurement of changes in the Antarctic ice sheet was given a very high priority in recommendations by the Polar Research Board of the National Research Council (1986), by the Scientific Committee on Antarctic Research (SCAR) (1989), and by the National Science Foundation's (1990) Division of Polar Programs. An archive of early 1970's Landsat 1, 2, and 3 Multispectral Scanner (MSS) images of Antarctica and the fact that the repeat coverage with satellite images provided an excellent means of documenting changes in the coastline of Antarctica provided the impetus for carrying out a comprehensive analysis of the glaciological features of the coastal regions and changes in ice fronts of Antarctica. The project was later modified to include Landsat 4 and 5 MSS and Thematic Mapper (TM) and RADARSAT images to compare changes over a 20- to 25- year time interval and to prepare a series of 24 1:1,000,000-scale and 1 1:5,000,000-scale U.S. Geological Survey Geologic Investigations Series Maps ('I-Maps') (Williams and others, 1995; Williams and Ferrigno, 1998; and Ferrigno and others, 2002) in both paper and digital format.

Transport of Biomass Burning Emissions from Southern Africa

NASA Technical Reports Server (NTRS)

Sinha, Parikhit; Jaegle,Lyatt; Hobbs, Peter V.; Liang, Qing

2004-01-01

The transport of biomass burning emissions from southern Africa to the neighboring Atlantic and Indian Oceans during the dry season (May-October) of 2000 is characterized using ground, ozonesonde, and aircraft measurements of carbon monoxide (CO) and ozone (O3) in and around southern Africa, together with the GEOS-CHEM global model of tropospheric chemistry. The model shows a positive bias of approximately 20% for CO and a negative bias of approximately 10-25% for O3 at oceanic sites downwind of fire emissions. Near areas of active fire emissions the model shows a negative bias of approximately 60% and approximately 30% for CO and O3, respectively, likely due to the coarse spatial (2 deg. x 2.5 deg.) and temporal (monthly) resolution of the model compared to that of active fires. On average, from 1994 to 2000, approximately 60 Tg of carbon monoxide (CO) from biomass burning in southern Africa was transported eastward to the Indian Ocean across the latitude band 0 deg. -60 S during the 6 months of the dry season. Over the same time period, approximately 40 Tg of CO from southern African biomass burning was transported westward to the Atlantic Ocean over the latitudes 0 deg. -20 S during the 6-month dry season, but most of that amount was transported back eastward over higher latitudes to the south (21 deg. -60 S). Eastward transport of biomass burning emissions from southern Africa enhances CO concentrations by approximately 4- 13 ppbv per month over the southern subtropical Indian Ocean during the dry season, with peak enhancements in September. Carbon monoxide from southern African and South American biomass burning is seen in the model simulations as far away as Australia, contributing approximately 8 ppbv and approximately 12-15 ppbv CO, respectively, and thus explaining the approximately 20- 25 ppbv observed enhancement of CO over Melbourne in mid-September 2000.

Status of DORIS stations in Antarctica for precise geodesy

NASA Technical Reports Server (NTRS)

Willis, P.; Amalvict, M.; Shibuya, K.

2005-01-01

In Antarctica, besides the quite numerous GPS stations, four DORIS stations are permanently operating. In addition to the permanent DORIS stations, episodic campaigns took place at DomeC/Conccordia and on Sorsdal and Lambert glaciers. In this paper, we first collect general information concerning the stations and the campaigns (location, start of measurements, etc). We then present the results of observations of the permanent stations keeping in mind that we are primarily interested here in the vertical component, which is the most uncertain component.

Macrofossil evidence for a rapid and severe Cretaceous–Paleogene mass extinction in Antarctica

PubMed Central

Witts, James D.; Whittle, Rowan J.; Wignall, Paul B.; Crame, J. Alistair; Francis, Jane E.; Newton, Robert J.; Bowman, Vanessa C.

2016-01-01

Debate continues about the nature of the Cretaceous–Paleogene (K–Pg) mass extinction event. An abrupt crisis triggered by a bolide impact contrasts with ideas of a more gradual extinction involving flood volcanism or climatic changes. Evidence from high latitudes has also been used to suggest that the severity of the extinction decreased from low latitudes towards the poles. Here we present a record of the K–Pg extinction based on extensive assemblages of marine macrofossils (primarily new data from benthic molluscs) from a highly expanded Cretaceous–Paleogene succession: the López de Bertodano Formation of Seymour Island, Antarctica. We show that the extinction was rapid and severe in Antarctica, with no significant biotic decline during the latest Cretaceous, contrary to previous studies. These data are consistent with a catastrophic driver for the extinction, such as bolide impact, rather than a significant contribution from Deccan Traps volcanism during the late Maastrichtian. PMID:27226414

New Antarctic Gravity Anomaly Grid for Enhanced Geodetic and Geophysical Studies in Antarctica

PubMed Central

Scheinert, M.; Ferraccioli, F.; Schwabe, J.; Bell, R.; Studinger, M.; Damaske, D.; Jokat, W.; Aleshkova, N.; Jordan, T.; Leitchenkov, G.; Blankenship, D. D.; Damiani, T. M.; Young, D.; Cochran, J. R.; Richter, T. D.

2018-01-01

Gravity surveying is challenging in Antarctica because of its hostile environment and inaccessibility. Nevertheless, many ground-based, airborne and shipborne gravity campaigns have been completed by the geophysical and geodetic communities since the 1980s. We present the first modern Antarctic-wide gravity data compilation derived from 13 million data points covering an area of 10 million km2, which corresponds to 73% coverage of the continent. The remove-compute-restore technique was applied for gridding, which facilitated levelling of the different gravity datasets with respect to an Earth Gravity Model derived from satellite data alone. The resulting free-air and Bouguer gravity anomaly grids of 10 km resolution are publicly available. These grids will enable new high-resolution combined Earth Gravity Models to be derived and represent a major step forward towards solving the geodetic polar data gap problem. They provide a new tool to investigate continental-scale lithospheric structure and geological evolution of Antarctica. PMID:29326484

New Antarctic Gravity Anomaly Grid for Enhanced Geodetic and Geophysical Studies in Antarctica

NASA Technical Reports Server (NTRS)

Scheinert, M.; Ferraccioli, F.; Schwabe, J.; Bell, R.; Studinger, M.; Damaske, D.; Jokat, W.; Aleshkova, N.; Jordan, T.; Leitchenkov, G.;

New Antarctic Gravity Anomaly Grid for Enhanced Geodetic and Geophysical Studies in Antarctica.

PubMed

Scheinert, M; Ferraccioli, F; Schwabe, J; Bell, R; Studinger, M; Damaske, D; Jokat, W; Aleshkova, N; Jordan, T; Leitchenkov, G; Blankenship, D D; Damiani, T M; Young, D; Cochran, J R; Richter, T D

2016-01-28

Gravity surveying is challenging in Antarctica because of its hostile environment and inaccessibility. Nevertheless, many ground-based, airborne and shipborne gravity campaigns have been completed by the geophysical and geodetic communities since the 1980s. We present the first modern Antarctic-wide gravity data compilation derived from 13 million data points covering an area of 10 million km 2 , which corresponds to 73% coverage of the continent. The remove-compute-restore technique was applied for gridding, which facilitated levelling of the different gravity datasets with respect to an Earth Gravity Model derived from satellite data alone. The resulting free-air and Bouguer gravity anomaly grids of 10 km resolution are publicly available. These grids will enable new high-resolution combined Earth Gravity Models to be derived and represent a major step forward towards solving the geodetic polar data gap problem. They provide a new tool to investigate continental-scale lithospheric structure and geological evolution of Antarctica.

Research of remote control for Chinese Antarctica Telescope based on iridium satellite communication

NASA Astrophysics Data System (ADS)

Xu, Lingzhe; Yang, Shihai

2010-07-01

Astronomers are ever dreaming of sites with best seeing on the Earth surface for celestial observation, and the Antarctica is one of a few such sites only left owing to the global air pollution. However, Antarctica region is largely unaccessible for human being due to lacking of fundamental living conditions, travel facilities and effective ways of communication. Worst of all, the popular internet source as a general way of communication scarcely exists there. Facing such a dilemma and as a solution remote control and data transmission for telescopes through iridium satellite communication has been put forward for the Chinese network Antarctic Schmidt Telescopes 3 (AST3), which is currently under all round research and development. This paper presents iridium satellite-based remote control application adapted to telescope control. The pioneer work in China involves hardware and software configuration utilizing techniques for reliable and secure communication, which is outlined in the paper too.

Antarctica and the strategic plan for biodiversity

PubMed Central

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

Absolute plate motion of Africa around Hawaii-Emperor bend time

NASA Astrophysics Data System (ADS)

Maher, S. M.; Wessel, P.; Müller, R. D.; Williams, S. E.; Harada, Y.

2015-06-01

Numerous regional plate reorganizations and the coeval ages of the Hawaiian Emperor bend (HEB) and Louisville bend of 50-47 Ma have been interpreted as a possible global tectonic plate reorganization at ˜chron 21 (47.9 Ma). Yet for a truly global event we would expect a contemporaneous change in Africa absolute plate motion (APM) reflected by physical evidence distributed on the Africa Plate. This evidence has been postulated to take the form of the Réunion-Mascarene bend which exhibits many HEB-like features, such as a large angular change close to ˜chron 21. However, the Réunion hotspot trail has recently been interpreted as a sequence of continental fragments with incidental hotspot volcanism. Here we show that the alternative Réunion-Mascarene Plateau trail can also satisfy the age progressions and geometry of other hotspot trails on the Africa Plate. The implied motion, suggesting a pivoting of Africa from 67 to 50 Ma, could explain the apparent bifurcation of the Tristan hotspot chain, the age reversals seen along the Walvis Ridge, the sharp curve of the Canary trail, and the diffuse nature of the St. Helena chain. To test this hypothesis further we made a new Africa APM model that extends back to ˜80 Ma using a modified version of the Hybrid Polygonal Finite Rotation Method. This method uses seamount chains and their associated hotspots as geometric constraints for the model, and seamount age dates to determine APM through time. While this model successfully explains many of the volcanic features, it implies an unrealistically fast global lithospheric net rotation, as well as improbable APM trajectories for many other plates, including the Americas, Eurasia and Australia. We contrast this speculative model with a more conventional model in which the Mascarene Plateau is excluded in favour of the Chagos-Laccadive Ridge rotated into the Africa reference frame. This second model implies more realistic net lithospheric rotation and far-field APMs, but

Antarctica obtained from a mosaic of 11 images taken by Galileo spacecraft

NASA Technical Reports Server (NTRS)

1990-01-01

Galileo spacecraft image of the Earth recorded after completing its first Earth Gravity Assist. This image of Antarctica was obtained from a mosaic of 11 images taken during a ten minute period near 5:45 pm Pacific Standard Time (PST) 12-08-90 by the Galileo spacecraft imaging system. Red, green, and violet filters were used. The picture spans about 1,600 miles across the south polar latitudes of our planet. The morning day/night terminator is toward the right. The South Pole is out of sight below the picture; the visible areas of Antarctica are those lying generally south of South America. The violet-blue envelope of Earth's atmosphere is prominent along the limb to the left. At lower left, the dark blue Amundsen Sea lies to the left of the Walgreen and Bakutis Coasts. Beyond it, Peter Island reacts with the winds to produce a striking pattern of atmospheric waves. Photo provided by the Jet Propulsion Laboratory (JPL) with alternate number P-37340, 12-19-90.

Active-site titration analysis of surface influence on immobilized Candida antarctica Lipase B activity

USDA-ARS?s Scientific Manuscript database

Matrix morphology and surface polarity effects were investigated for Candida antarctica lipase B immobilization. Measurements of the amount of lipase immobilized (bicinchoninic acid method) and the catalyst’s tributyrin hydrolysis activity, coupled with a determination of the lipase’s functional fr...

Australia: Population.

PubMed

The Australian Bureau of Census and Statistics reported on 27 August 1979 that Australia's total population was 14,376,400 at the end of the first quarter of 1979. Net immigration gain during the same period was 12,700. Natural increase was 32,100--births were 57,100 and deaths were 25,000. In January 1979, Australia introduced a new immigration scheme to improve methods of selecting immigrants. Points are awarded on the basis of personal qualities and employability; an applicant must score 60 out of 100. This scheme supersedes the earlier system under which immigrants were selected on the family reunion criterion and employability. Migrants from Britain and Ireland made up the bulk of the new comers, but their proportion has dropped from 50% in the mid-1960s to 30% in early 1979. In contrast, Asian immigrants have risen from 2% to 22% over the same period. Asian immigration began in the mid-1960s with the relaxation of the "White Australia" policy which barred non-European migrants, and increased when the ban was abolished by Prime Minister Gough Whitlam in 1973.

Leishmanicidal and antitumoral activities of endophytic fungi associated with the Antarctic angiosperms Deschampsia antarctica Desv. and Colobanthus quitensis (Kunth) Bartl.

PubMed

Santiago, Iara F; Alves, Tânia M A; Rabello, Ana; Sales Junior, Policarpo A; Romanha, Alvaro J; Zani, Carlos L; Rosa, Carlos A; Rosa, Luiz H

2012-01-01

A total of 564 isolates of endophytic fungi were recovered from the plants Deschampsia antarctica and Colobanthus quitensis collected from Antarctica. The isolates were screened against parasites Leishmania amazonensis and Trypanosoma cruzi and against the human tumour cell lines. Of the 313 fungal isolates obtained from D. antarctica and 251 from C. quitensis, 25 displayed biological activity. Nineteen extracts displayed leishmanicidal activity, and six inhibited the growth of at least one tumour cell line. These fungi belong to 19 taxa of the genera Alternaria, Antarctomyces, Cadophora, Davidiella, Helgardia, Herpotrichia, Microdochium, Oculimacula, Phaeosphaeria and one unidentified fungus. Extracts of 12 fungal isolates inhibited the proliferation of L. amazonesis at a low IC(50) of between 0.2 and 12.5 μg ml(-1). The fungus Phaeosphaeria herpotrichoides displayed only leishmanicidal activity with an IC(50) of 0.2 μg ml(-1), which is equivalent to the inhibitory value of amphotericin B. The extract of Microdochium phragmitis displayed specific cytotoxic activity against the UACC-62 cell line with an IC(50) value of 12.5 μg ml(-1). Our results indicate that the unique angiosperms living in Antarctica shelter an interesting bioactive fungal community that is able to produce antiprotozoal and antitumoral molecules. These molecules may be used to develop new leishmanicidal and anticancer drugs.

Community Music in Australia

ERIC Educational Resources Information Center

Harrison, Gillian

2010-01-01

This paper presents a historical perspective to the development of community music in Australia. Finding political support in Australia's progressive arts policies of the late 1970s, community music is discussed as embracing the principles of access and equity and supporting the development of musical skills in the context of social change and…

Online Training in Australia

ERIC Educational Resources Information Center

Kuzic, Joze

2013-01-01

On-line training is becoming an interesting phenomenon in Australia and has attracted a lot of interest across many industries and businesses (Chan and Ngai, 2007). The research reported here looks at the use of online training in corporations in Australia. It focuses on two aspects of online training, the factors that "warrant" its…

Breathing new life into old collections - revitalising Geoscience Australia Microscope Slide Based collections through the use of Citizen Science

NASA Astrophysics Data System (ADS)

Bastrakova, I.; Pring, J.; Blewett, R.; Champion, D. C.; Poignand, B.; Raymond, O.; Evans, N.; Stewart, A.; Butler, P.

2017-12-01

Since soon after the federation of Australia in 1901 Geoscience Australia, and its predecessors organisations, have gathered a significant collection of microscope slide based items (including: thin sections of rock, micro and nano fossils) from across Australia, Antarctica, Papua New Guinea, the Asia Pacific region and beyond. The samples from which the microscope slides were produced have been gathered via extensive geological mapping programs, work conducted for major Commonwealth building initiatives such as the Snowy Mountain Scheme and science expeditions. The cost of recreating this collection, if at all possible, would be measured in the $100Ms (AUS) even assuming that it was still possible to source the relevant samples. While access to these microscope slides is open to industry, educational institutions and the public it has not been easy to locate specific slides due to the management system. The management of this collection was based largely on an aged card catalogue and ledger system. The fragmented nature of the management system with the increasing potential for the deterioration of physical media and the loss of access to even some of the original contributors meant that rescue work was (and still is) needed urgently. Achieving progress on making the microscope slides discoverable and accessible in the current fiscally constrained environment dictated a departure from what might be considered a traditional approach to the project and saw the extensive use of a citizen science approach. Through the use of a citizen science approach the proof of concept project has seen the transcription of some 35,000 sample metadata and data records (2.5 times our current electronic holdings) from a variety of hardcopy sources by a diverse group of volunteers. The availability of this data has allowed for the electronic discovery of both the microscope slides and their parent samples, and will hopefully lead to a greater utilisation of this valuable resource and

EHDI Africa: advocating for infants with hearing loss in Africa.

PubMed

Swanepoel, DeWet; Störbeck, Claudine

2008-01-01

Children with hearing loss who happen to reside in Africa deserve the chance to develop according to their potential as much as their peers living in more affluent regions. This leaves a moral obligation to pursue ways of initiating, developing,and growing early hearing detection and intervention services in Africa. For these reasons, the first EHDI Africa international conference was held in Johannesburg, South Africa, in 2007 (13-14 August). The theme was 'Building bridges in Africa: Early childhood development for children with hearing loss'. This special issue contains several reports from the EHDI Africa conference.

Soil-landform-plant communities relationships of a periglacial landscape at Potter Peninsula, Maritime Antarctica

NASA Astrophysics Data System (ADS)

Poelking, E. L.; Schaefer, C. E. R.; Fernandes Filho, E. I.; de Andrade, A. M.; Spielmann, A. A.

2014-08-01

Integrated studies on the interplay between soils, periglacial geomorphology and plant communities are crucial for the understanding of climate change effects on terrestrial ecosystems of Maritime Antarctica, one of the most sensitive areas to global warming. Knowledge on physical environmental factors that influence plant communities can greatly benefit studies on monitoring climate change in Maritime Antarctica, where new ice-free areas are being constantly exposed, allowing plant growth and organic carbon inputs. The relationship between topography, plant communities and soils was investigated in Potter Peninsula, King George Island, Maritime Antarctica. We mapped the occurrence and distribution of plant communities and identified soil-landform-vegetation relationships. The vegetation map was obtained by classification of a Quickbird image, coupled with detailed landform and characterization of 18 soil profiles. The sub-formations were identified and classified, and we also determined the total elemental composition of lichens, mosses and grasses. Plant communities at Potter Peninsula occupy 23% of the ice-free area, at different landscape positions, showing decreasing diversity and biomass from the coastal zone to inland areas where sub-desert conditions prevail. There is a clear dependency between landform and vegetated soils. Soils with greater moisture or poorly drained, and acid to neutral pH, are favourable for mosses subformations. Saline, organic-matter rich ornithogenic soils of former penguin rookeries have greater biomass and diversity, with mixed associations of mosses and grasses, while stable felseenmeers and flat rocky cryoplanation surfaces are the preferred sites for Usnea and Himantormia lugubris lichens, at the highest surface. Lichens subformations cover the largest vegetated area, showing varying associations with mosses.

Scientific Experiences Using Argentinean Sounding Rockets in Antarctica

NASA Astrophysics Data System (ADS)

Sánchez-Peña, Miguel

2000-07-01

Argentina in the sixties and seventies, had experience for developing and for using sounding rockets and payloads to perform scientific space experiments. Besides they have several bases in Antarctica with adequate premises and installations, also duly equipped aircrafts and trained crews to flight to the white continent. In February 1965, scientists and technical people from the "Instituto de Investigacion Aeronáutica y Espacial" (I.I.A.E.) with the cooperation of the Air Force and the Tucuman University, conducted the "Matienzo Operation" to measure X radiation and temperature in the upper atmosphere, using the Gamma Centauro rocket and also using big balloons. The people involved in the experience, the launcher, other material and equipment flew from the south tip of Argentina to the Matienzo base in Antarctica, in a C-47 aircraft equipped with skies an additional jet engine Marbore 2-C. Other experience was performed in 1975 in the "Marambio" Antartic Base, using the two stages solid propellent sounding rocket Castor, developed in Argentina. The payload was developed in cooperation with the Max Planck Institute of Germany. It consist of a special mixture including a shape charge to form a ionized cloud producing a jet of electrons travelling from Marambio base to the conjugate point in the Northern hemisphere. The cloud was observed by several ground stations in Argentina and also by a NASA aircraft with TV cameras, flying at East of New York. The objective of this experience was to study the electric and magnetic fields in altitude, the neutral points, the temperature and electrons profile. The objectives of both experiments were accomplished satisfactorily.

Coastal-change and glaciological maps of Antarctica

USGS Publications Warehouse

Williams, Richard S.

2004-01-01

Changes in the area and volume of polar ice sheets are intricately linked to changes in global climate, and the resulting changes in sea level may severely impact the densely populated coastal regions on Earth. Melting of the West Antarctic part alone of the Antarctic ice sheet could cause a sea-level rise of approximately 6 meters (m). The potential sea-level rise after melting of the entire Antarctic ice sheet is estimated to be 65 m (Lythe and others, 2001) to 73 m (Williams and Hall, 1993). In spite of its importance, the mass balance (the net volumetric gain or loss) of the Antarctic ice sheet is poorly known; it is not known for certain whether the ice sheet is growing or shrinking. In a review paper, Rignot and Thomas (2002) concluded that the West Antarctic part of the Antarctic ice sheet is probably becoming thinner overall; although the western part is thickening, the northern part is thinning. Joughin and Tulaczyk (2002), based on analysis of ice-flow velocities derived from synthetic aperture radar, concluded that most of the Ross ice streams (ice streams on the east side of the Ross Ice Shelf) have a positive mass balance. The mass balance of the East Antarctic is unknown, but thought to be in near equilibrium. Measurement of changes in area and mass balance of the Antarctic ice sheet was given a very high priority in recommendations by the Polar Research Board of the National Research Council (1986), in subsequent recommendations by the Scientific Committee on Antarctic Research (SCAR) (1989, 1993), and by the National Science Foundation's (1990) Division of Polar Programs. On the basis of these recommendations, the U.S. Geological Survey (USGS) decided that the archive of early 1970s Landsat 1, 2, and 3 Multispectral Scanner (MSS) images of Antarctica and the subsequent repeat coverage made possible with Landsat and other satellite images provided an excellent means of documenting changes in the coastline of Antarctica (Ferrigno and Gould, 1987). The

Space Radar Image of Weddell Sea, Antarctica

NASA Image and Video Library

1999-05-01

This Spaceborne Imaging Radar-C/X-band Synthetic Aperture Radar color composite shows a portion of the Weddell Sea, which is adjacent to the continent of Antarctica. The image shows extensive coverage of first-year sea ice mixtures and patches of open water inside the ice margin. The image covers a 100 kilometer by 30 kilometer (62 mile by 18.5 mile) region of the southern ocean, centered at approximately 57 degrees south latitude and 3 degrees east longitude, which was acquired on October 3, 1994. Data used to create this image were obtained using the L-band (horizontally transmitted and vertically received) in red; the L-band (horizontally transmitted and received) in green; and the C-band (horizontally transmitted and received) in blue. The sea ice, which appears rust-brown in the image, is composed of loosely packed floes from approximately 1 meter to 2 meters (3 feet to 6.5 feet) thick and ranging from 1 meter to 20 meters (3 feet to 65.5 feet) in diameter. Large patches of open water, shown as turquoise blue, are scattered throughout the area, which is typical for ice margins experiencing off-ice winds. The thin, well-organized lines clearly visible in the ice pack are caused by radar energy reflected by floes riding the crest of ocean swells. The wispy, black features seen throughout the image represent areas where new ice is forming. Sea ice, because it acts as an insulator, reduces the loss of heat between the relatively warm ocean and cold atmosphere. This interaction is an important component of the global climate system. Because of the unique combination of winds, currents and temperatures found in this region, ice can extend many hundreds of kilometers north of Antarctica each winter, which classifies the Weddell Sea as one of nature's greatest ice-making engines. During the formation of sea ice, great quantities of salt are expelled from the frozen water. The salt increases the density of the upper layer of sea water, which then sinks to great depths

Flooding in Rockhampton, Queensland, Australia

NASA Image and Video Library

2011-01-07

On Jan. 7, 2011, NASA Terra spacecraft captured this image of the inundated city of Rockhampton, Queensland, Australia. Torrential rains in NE Australia caused the Fitzroy River to overflow its banks and flood much of the city.

Changes in heavy metals in Antarctic snow from Coats Land since the mid-19th to the late-20th century

NASA Astrophysics Data System (ADS)

Planchon, Frédéric A. M.; Boutron, Claude F.; Barbante, Carlo; Cozzi, Giulio; Gaspari, Vania; Wolff, Eric W.; Ferrari, Christophe P.; Cescon, Paolo

2002-06-01

V, Cr, Mn, Cu, Zn, Co, Ag, Cd, Ba, Pb, Bi and U have been measured in a series of dated snow samples, covering the period from 1834 to 1990, collected at remote, low accumulation sites in Coats Land, Antarctica. They were determined by ultrasensitive inductively coupled sector field mass spectrometry in ultraclean conditions. Concentrations are found to be extremely low, down to 3×10 -15 g/g, for most metals, then confirming the high purity of Antarctic snow. The results show contrasting time trends for the different metals. For Mn, Co, Ba, and possibly V and Cd, no clear time trends are observed. For Cr, Cu, Zn, Ag, Pb, Bi and U, on the other hand, pronounced enhancements are observed during the recent decades. They are attributed to emissions of heavy metals to the atmosphere from human activities in Southern America, Southern Africa and Australia, especially non-ferrous metal mining and smelting in Chile, Peru, Zaire, Zambia and Australia. It shows that atmospheric pollution for heavy metals in the remote Antarctic continent is not limited to Pb and Cu, as previously thought, but also affects several other metals. It is a further indication that atmospheric pollution for heavy metals is really global.

The End of the Cold Loneliness: 3D Comparison between Doto antarctica and a New Sympatric Species of Doto (Heterobranchia: Nudibranchia).

PubMed

Moles, Juan; Wägele, Heike; Ballesteros, Manuel; Pujals, Álvaro; Uhl, Gabriele; Avila, Conxita

2016-01-01

Although several studies are devoted to determining the diversity of Antarctic heterobranch sea slugs, new species are still being discovered. Among nudibranchs, Doto antarctica Eliot, 1907 is the single species of this genus described from Antarctica hitherto, the type locality being the Ross Sea. Doto antarctica was described mainly using external features. During our Antarctic research on marine benthic invertebrates, we found D. antarctica in the Weddell Sea and Bouvet Island, suggesting a circumpolar distribution. Species affiliation is herein supported by molecular analyses using cytochrome c oxidase subunit I, 16S rRNA, and histone H3 markers. We redescribe D. antarctica using histology, micro-computed tomography (micro-CT), and 3D-reconstruction of the internal organs. Moreover, we describe a new, sympatric species, namely D. carinova Moles, Avila & Wägele n. sp., and provide an anatomical comparison between the two Antarctic Doto species. Egg masses in both species are also described here for the first time. We demonstrate that micro-CT is a useful tool for non-destructive anatomical description of valuable specimens. Furthermore, our high resolution micro-CT data reveal that the central nervous system of both Doto species possesses numerous accessory giant cells, suggested to be neurons herein. In addition, the phylogenetic tree of all Doto species sequenced to date suggests a scenario for the evolution of the reproductive system in this genus: bursa copulatrix seems to have been reduced and the acquisition of a distal connection of the oviduct to the nidamental glands is a synapomorphy of the Antarctic Doto species. Overall, the combination of thorough morphological and anatomical description and molecular analyses provides a comprehensive means to characterize and delineate species, thus suggesting evolutionary scenarios.

The End of the Cold Loneliness: 3D Comparison between Doto antarctica and a New Sympatric Species of Doto (Heterobranchia: Nudibranchia)

PubMed Central

Wägele, Heike; Ballesteros, Manuel; Pujals, Álvaro; Uhl, Gabriele; Avila, Conxita

2016-01-01

Although several studies are devoted to determining the diversity of Antarctic heterobranch sea slugs, new species are still being discovered. Among nudibranchs, Doto antarctica Eliot, 1907 is the single species of this genus described from Antarctica hitherto, the type locality being the Ross Sea. Doto antarctica was described mainly using external features. During our Antarctic research on marine benthic invertebrates, we found D. antarctica in the Weddell Sea and Bouvet Island, suggesting a circumpolar distribution. Species affiliation is herein supported by molecular analyses using cytochrome c oxidase subunit I, 16S rRNA, and histone H3 markers. We redescribe D. antarctica using histology, micro-computed tomography (micro-CT), and 3D-reconstruction of the internal organs. Moreover, we describe a new, sympatric species, namely D. carinova Moles, Avila & Wägele n. sp., and provide an anatomical comparison between the two Antarctic Doto species. Egg masses in both species are also described here for the first time. We demonstrate that micro-CT is a useful tool for non-destructive anatomical description of valuable specimens. Furthermore, our high resolution micro-CT data reveal that the central nervous system of both Doto species possesses numerous accessory giant cells, suggested to be neurons herein. In addition, the phylogenetic tree of all Doto species sequenced to date suggests a scenario for the evolution of the reproductive system in this genus: bursa copulatrix seems to have been reduced and the acquisition of a distal connection of the oviduct to the nidamental glands is a synapomorphy of the Antarctic Doto species. Overall, the combination of thorough morphological and anatomical description and molecular analyses provides a comprehensive means to characterize and delineate species, thus suggesting evolutionary scenarios. PMID:27411060

Changing profile of couples seeking genetic counseling for consanguinity in Australia.

PubMed

Port, Katrina E; Mountain, Helen; Nelson, John; Bittles, Alan H

2005-01-15

Consanguineous marriage is rare in most Western countries and, for example, in the USA it may be subject to regulation by both civil legislation and religious prescription. This is not the case in many regions of Asia and Africa where marriage within the family is strongly favored. Since the 1970s there has been widespread migration to North America, Western Europe, and Australasia from communities which encourage consanguineous marriage. To assess the effect of this trend on a genetic counseling program, the records of 302 couples referred to Genetic Services of Western Australia for consanguinity counseling were abstracted for the period 1975-2001. Overall, a family history of genetic disease or a previously affected child was reported in 28.8% of cases. Premarital or prepregnancy counseling on grounds of consanguinity was sought by 41.0% of couples, and a further 18.2% of consanguineous couples had been referred because of a consanguineous pregnancy. In 7.6% of cases a relationship closer than first cousin was involved. Through time there was a significant increase in the numbers of consanguineous consultants, and their patterns of religious affiliation and ethnic origin widened markedly. Although effectively excluded from entry to Australia prior to 1975, couples of Asian origin accounted for 25.5% of all consanguineous consultants. With ongoing migration, changes in the ethnic profiles and the specific counseling requirements of consanguineous couples can be expected to continue and probably accelerate.

How does ice sheet loading affect ocean flow around Antarctica?

NASA Astrophysics Data System (ADS)

Dijkstra, H. A.; Rugenstein, M. A.; Stocchi, P.; von der Heydt, A. S.

2012-12-01

Interactions and dynamical feedbacks between ocean circulation, heat and atmospheric moisture transport, ice sheet evolution, and Glacial Isostatic Adjustment (GIA) are overlooked issues in paleoclimatology. Here we will present first results on how ocean flows were possibly affected by the glaciation of Antarctica across the Eocene-Oligocene Transition (~ 34 Ma) through GIA and bathymetry variations. GIA-induced gravitationally self-consistent bathymetry variations are determined by solving the Sea Level Equation (SLE), which describes the time dependent shape of (i) the solid Earth and (ii) the equipotential surface of gravity. Since the ocean circulation equations are defined relative to the equipotential surface of gravity, only bathymetry variations can influence ocean flows, although the sea surface slope will also change through time due to gravitational attraction. We use the Hallberg Isopycnal Model under late Eocene conditions to calculate equilibrium ocean flows in a domain in which the bathymetry evolves under ice loading according to the SLE. The bathymetric effects of the glaciation of Antarctica lead to substantial spatial changes in ocean flows, and close to the coast, the flow even reverses direction. Volume transports through the Drake Passage and Tasman Seaway adjust to the new bathymetry. The results indicate that GIA-induced ocean flow variations alone may have had an impact on sedimentation and erosion patterns, the repositioning of fronts, ocean heat transport and grounding line and ice sheet stability.

A transcriptome resource for the Antarctic pteropod Limacina helicina antarctica.

PubMed

Johnson, Kevin M; Hofmann, Gretchen E

2016-08-01

The pteropod Limacina helicina antarctica is a dominant member of the zooplankton assemblage in the Antarctic marine ecosystem, and is part of a relatively simple food web in nearshore marine Antarctic waters. As a shelled pteropod, Limacina has been suggested as a candidate sentinel organism for the impacts of ocean acidification, due to the potential for shell dissolution in undersaturated waters. In this study, our goal was to develop a transcriptomic resource for Limacina that would support mechanistic studies to explore the physiological response of Limacina to abiotic stressors such as ocean acidification and ocean warming. To this end, RNA sequencing libraries were prepared from Limacina that had been exposed to a range of pH levels and an elevated temperature to maximize the diversity of expressed genes. RNA sequencing (RNA-seq) was conducted on an Illumina NextSeq500 which produced 339,000,000 150bp paired-end reads. The de novo transcriptome was produced using Trinity and annotation of the assembled transcriptome resulted in the identification of 81,229 transcripts in 137 KEGG pathways. This RNA-seq effort resulted in a transcriptome for the Antarctic pteropod, Limacina helicina antarctica, that is a major resource for an international marine science research community studying these pelagic molluscs in a global change context. Copyright © 2016 Elsevier B.V. All rights reserved.

Influence of cosolvents on the hydrophobic surface immobilization topography of Candida antarctica lipase B

USDA-ARS?s Scientific Manuscript database

The presence of cosolvents and co-solutes during the immobilization of lipases on hydrophobic supports may influence the extent of lipase immobilization and the long-term catalytic stability of the biocatalyst. Candida antarctica B lipase immobilization was examined on a hydrophobic surface, i.e., ...

Remote sensing and skywave digital communication from antarctica.

PubMed

Bergadà, Pau; Deumal, Marc; Vilella, Carles; Regué, Joan R; Altadill, David; Marsal, Santi

2009-01-01

This paper presents an overview of the research activities undertaken by La Salle and the Ebro Observatory in the field of remote sensing. On 2003 we started a research project with two main objectives: implement a long-haul oblique ionospheric sounder and transmit the data from remote sensors located at the Spanish Antarctic station Juan Carlos I to Spain. The paper focuses on a study of feasibility of two possible physical layer candidates for the skywave link between both points. A DS-SS based solution and an OFDM based solution are considered to achieve a reliable low-power low-rate communication system between Antarctica and Spain.

Remote Sensing and Skywave Digital Communication from Antarctica

PubMed Central

Bergadà, Pau; Deumal, Marc; Vilella, Carles; Regué, Joan R.; Altadill, David; Marsal, Santi

2009-01-01

This paper presents an overview of the research activities undertaken by La Salle and the Ebro Observatory in the field of remote sensing. On 2003 we started a research project with two main objectives: implement a long-haul oblique ionospheric sounder and transmit the data from remote sensors located at the Spanish Antarctic station Juan Carlos I to Spain. The paper focuses on a study of feasibility of two possible physical layer candidates for the skywave link between both points. A DS-SS based solution and an OFDM based solution are considered to achieve a reliable low-power low-rate communication system between Antarctica and Spain. PMID:22303166

Splendid and Seldom Isolated: The Paleobiogeography of Patagonia

NASA Astrophysics Data System (ADS)

Wilf, Peter; Cúneo, N. Rubén; Escapa, Ignacio H.; Pol, Diego; Woodburne, Michael O.

2013-05-01

The idea that South America was an island continent over most of the Cenozoic, during which its unusual mammalian faunas evolved in isolation, is outstandingly influential in biogeography. Although large numbers of recent fossil discoveries and related advances require that the original isolation concept be significantly modified, it is still repeated in much current literature. The persistence of the idea inspired us to present here an integrated paleobiogeographic account of mammals, reptiles, and plants from the Jurassic to the Paleogene of Patagonia, which has by far the richest fossil record on the continent. All three groups show distribution patterns that are broadly consistent with South America's long separation history, first from Laurasia by the Late Jurassic, then from Africa and India-Madagascar during the late Early Cretaceous, and finally from Antarctica and Australia during the early-middle Eocene, after which “isolation” finally commenced. We highlight areas of promising future research and provide an updated view of South American isolation.

Spatial Variability of Perchlorate along a Traverse Route from Zhongshan Station to Dome A, East Antarctica

NASA Astrophysics Data System (ADS)

Jiang, S.; Cole-Dai, J.; Li, Y.; An, C.

2016-12-01

Snow deposition and accumulation on the Antarctic ice sheet preserve records of climatic change, as well as those of chemical characteristics of the environment. Chemical composition of snow and ice cores can be used to track the sources of important substances including pollutants and to investigate relationships between atmospheric chemistry and climatic conditions. Recent development in analytical methodology has enabled the determination of ultra-trace levels of perchlorate in polar snow. We have measured perchlorate concentrations in surface snow samples collected along a traverse route from Zhongshan Station to Dome A in East Antarctica to determine the level of atmospheric perchlorate in East Antarctica and to assess the spatial variability of perchlorate along the traverse route. Results show that the perchlorate concentrations vary between 32 and 200 ng kg-1, with an average of 104.3 ng kg-1. And perchlorate concentration profile presents regional variation patterns along the traverse route. In the coastal region, perchlorate concentration displays an apparent decreasing relationship with increasing distance inland; it exhibits no apparent trend in the intermediate region from 200 to 1000 km. The inland region from 1000 to 1244 km presents a generally increasing trend of perchlorate concentration approaching the dome. Different rates of atmospheric production, dilution by snow accumulation and re-deposition of snow-emitted perchlorate (post-depositional change) are the three possible factors influencing the spatial variability of perchlorate over Antarctica.

NASA-ISRO synthetic aperture radar (NISAR) for temporal tracking of iceberg calving events in the Antarctica

NASA Astrophysics Data System (ADS)

Jawak, S. D.; Luis, A. J.

2017-12-01

Estimating mass loss of the Antarctic ice sheet caused by iceberg calving is a challenging job. Antarctica is surrounded by a variety of large, medium and small sized ice shelves, glacier tongues and coastal areas without offshore floating ice masses. It is possible to monitor surface structures on the continental ice and the ice shelves as well as calved icebergs using NASA-ISRO synthetic aperture radar (NISAR) satellite images in future. The NISAR, which is planned to be launched in 2020, can be used as an all-weather and all-season system to classify the coastline of Antarctica to map patterns of surface structures close to the calving front. Additionally, classifying patterns and density of surface structures distributed over the ice shelves and ice tongues can be a challenging research where NISAR can be of a great advantage. So this work explores use of NISAR to map surface structures visible on ice shelves which can provide advisories to field teams. The ice shelf fronts has been categorized into various classes based on surface structures relative to the calving front within a 30 km-wide seaward strip. The resulting map of the classified calving fronts around Antarctica and their description would provide a detailed representation of crevasse formation and dominant iceberg in the southern ocean which pose a threat to navigation of Antarctic bound ships.

Perennially ice-covered Lake Hoare, Antarctica: physical environment, biology and sedimentation

NASA Technical Reports Server (NTRS)

Wharton, R. A. Jr; Simmons, G. M. Jr; McKay, C. P.; Wharton RA, J. r. (Principal Investigator)

1989-01-01

Lake Hoare (77 degrees 38' S, 162 degrees 53' E) is a perennially ice-covered lake at the eastern end of Taylor Valley in southern Victoria Land, Antarctica. The environment of this lake is controlled by the relatively thick ice cover (3-5 m) which eliminates wind generated currents, restricts gas exchange and sediment deposition, and reduces light penetration. The ice cover is in turn largely controlled by the extreme seasonality of Antarctica and local climate. Lake Hoare and other dry valley lakes may be sensitive indicators of short term (< 100 yr) climatic and/or anthropogenic changes in the dry valleys since the onset of intensive exploration over 30 years ago. The time constants for turnover of the water column and lake ice are 50 and 10 years, respectively. The turnover time for atmospheric gases in the lake is 30-60 years. Therefore, the lake environment responds to changes on a 10-100 year timescale. Because the ice cover has a controlling influence on the lake (e.g. light penetration, gas content of water, and sediment deposition), it is probable that small changes in ice ablation, sediment loading on the ice cover, or glacial meltwater (or groundwater) inflow will affect ice cover dynamics and will have a major impact on the lake environment and biota.

22 CFR 120.35 - Australia Implementing Arrangement.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 22 Foreign Relations 1 2014-04-01 2014-04-01 false Australia Implementing Arrangement. 120.35 Section 120.35 Foreign Relations DEPARTMENT OF STATE INTERNATIONAL TRAFFIC IN ARMS REGULATIONS PURPOSE AND DEFINITIONS § 120.35 Australia Implementing Arrangement. Australia Implementing Arrangement means the...

Tectonic and erosion-driven uplift in the Gamburtsev Subglacial Mountains of East Antarctica

NASA Astrophysics Data System (ADS)

Ferraccioli, Fausto; Jordan, Tom; Watts, Tony; Bell, Robin; Jamieson, Stewart; Finn, Carol; Damaske, Detlef

2014-05-01

Understanding the mechanisms leading to intraplate mountain building remains a significant challenge in Earth Sciences compared to ranges formed along plate margins. The most enigmatic intraplate mountain range on Earth is the Gamburtsev Subglacial Mountains (GSM) located in the middle of the Precambrian East Antarctic Craton. During the International Polar Year, the AGAP project acquired 120,000 line km of new airborne geophysical data (Bell et al., 2011, Science) and seismological observations (Hansen et al., 2010, EPSL) across central East Antarctica. Models derived from these datasets provide new geophysical perspectives on crustal architecture and possible uplift mechanisms for the enigmatic GSM (Ferraccioli et al., 2011, Nature). The geophysical data define a 2,500-km-long Paleozoic to Mesozoic rift system in East Antarctica surrounding the GSM. A thick high-density lower crustal root is partially preserved beneath the range and has been interpreted as formed during the Proterozoic assembly of East Antarctica. Rifting could have triggered phase/density changes at deep crustal levels, perhaps restoring some of the latent root buoyancy, as well as causing rift-flank uplift. Permian rifting is well-established in the adjacent Lambert Rift, and was followed by Cretaceous strike-slip faulting and transtension associated with Gondwana break-up; this phase may have provided a more recent tectonic trigger for the initial uplift of the modern GSM. The Cretaceous rift-flank uplift model for the Gamburtsevs is appealing because it relates the initiation of intraplate mountain-building to large-scale geodynamic processes that led to the separation of Greater India from East Antarctica. It is also consistent with several geological and geophysical interpretations within the Lambert Rift. However, recent detrital thermochrology results from Oligocene-Quaternary sediments in Prydz Bay (Tochlin et al., 2012, G3) argue against the requirement for major Cretaceous rift

Recombinant protein secretion in Pseudozyma flocculosa and Pseudozyma antarctica with a novel signal peptide.

PubMed

Cheng, Yali; Avis, Tyler J; Bolduc, Sébastien; Zhao, Yingyi; Anguenot, Raphaël; Neveu, Bertrand; Labbé, Caroline; Belzile, François; Bélanger, Richard R

2008-12-01

Secretion of recombinant proteins aims to reproduce the correct posttranslational modifications of the expressed protein while simplifying its recovery. In this study, secretion signal sequences from an abundantly secreted 34-kDa protein (P34) from Pseudozyma flocculosa were cloned. The efficiency of these sequences in the secretion of recombinant green fluorescent protein (GFP) was investigated in two Pseudozyma species and compared with other secretion signal sequences, from S. cerevisiae and Pseudozyma spp. The results indicate that various secretion signal sequences were functional and that the P34 signal peptide was the most effective secretion signal sequence in both P. flocculosa and P. antarctica. The cells correctly processed the secretion signal sequences, including P34 signal peptide, and mature GFP was recovered from the culture medium. This is the first report of functional secretion signal sequences in P. flocculosa. These sequences can be used to test the secretion of other recombinant proteins and for studying the secretion pathway in P. flocculosa and P. antarctica.

Assessing the effectiveness of specially protected areas for conservation of Antarctica's botanical diversity.

PubMed

Hughes, Kevin A; Ireland, Louise C; Convey, Peter; Fleming, Andrew H

2016-02-01

Vegetation is sparsely distributed over Antarctica's ice-free ground, and distinct plant communities are present in each of the continent's 15 recently identified Antarctic Conservation Biogeographic Regions (ACBRs). With rapidly increasing human activity in Antarctica, terrestrial plant communities are at risk of damage or destruction by trampling, overland transport, and infrastructure construction and from the impacts of anthropogenically introduced species, as well as uncontrollable pressures such as fur seal (Arctocephalus gazella) activity and climate change. Under the Protocol on Environmental Protection to the Antarctic Treaty, the conservation of plant communities can be enacted and facilitated through the designation of Antarctic Specially Protected Areas (ASPAs). We examined the distribution within the 15 ACBRs of the 33 ASPAs whose explicit purpose includes protecting macroscopic terrestrial flora. We completed the first survey using normalized difference vegetation index (NDVI) satellite remote sensing to provide baseline data on the extent of vegetation cover in all ASPAs designated for plant protection in Antarctica. Large omissions in the protection of Antarctic botanical diversity were found. There was no protection of plant communities in 6 ACBRs, and in another 6, <0.4% of the ACBR area was included in an ASPA that protected vegetation. Protected vegetation cover within the 33 ASPAs totaled 16.1 km(2) for the entire Antarctic continent; over half was within a single protected area. Over 96% of the protected vegetation was contained in 2 ACBRs, which together contributed only 7.8% of the continent's ice-free ground. We conclude that Antarctic botanical diversity is clearly inadequately protected and call for systematic designation of ASPAs protecting plant communities by the Antarctic Treaty Consultative Parties, the members of the governing body of the continent. © 2015 The Authors. Conservation Biology published by Wiley Periodicals, Inc. on