Journal articles on the topic 'Antarctic Ocean and Antarctica'
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1
Sirenko, B. I. "First finding of a widely distributed Antarctic chiton species (Mollusca: Polyplacophora) in the North Pacific." Ruthenica, Russian Malacological Journal 29, no. 1 (January 14, 2019): 71–74. http://dx.doi.org/10.35885/ruthenica.2019.29(1).3.
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For the first time, the widely spread Antarctic species Leptochiton antarcticus was found at the Emperor Seamounts in the North Pacific Ocean. In spite of a large distance between the Emperor Seamounts and Antarctica, the found specimen have very similar shell, girdle, radula and gill features to the type material. I propose that L. antarcticus spread to the North Pacific from the Antarctic via a deep-water current near the ocean floor, and perhaps it inhabits the slopes of islands and continents from the South Ocean to the Emperor Seamounts.
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Jun, Sang-Yoon, Joo-Hong Kim, Jung Choi, Seong-Joong Kim, Baek-Min Kim, and Soon-Il An. "The internal origin of the west-east asymmetry of Antarctic climate change." Science Advances 6, no. 24 (June 2020): eaaz1490. http://dx.doi.org/10.1126/sciadv.aaz1490.
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Recent Antarctic surface climate change has been characterized by greater warming trends in West Antarctica than in East Antarctica. Although this asymmetric feature is well recognized, its origin remains poorly understood. Here, by analyzing observation data and multimodel results, we show that a west-east asymmetric internal mode amplified in austral winter originates from the harmony of the atmosphere-ocean coupled feedback off West Antarctica and the Antarctic terrain. The warmer ocean temperature over the West Antarctic sector has positive feedback, with an anomalous upper-tropospheric anticyclonic circulation response centered over West Antarctica, in which the strength of the feedback is controlled by the Antarctic topographic layout and the annual cycle. The current west-east asymmetry of Antarctic surface climate change is undoubtedly of natural origin because no external factors (e.g., orbital or anthropogenic factors) contribute to the asymmetric mode.
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Jacka, Tim H., William F. Budd, and Andrew Holder. "A further assessment of surface temperature changes at stations in the Antarctic and Southern Ocean, 1949–2002." Annals of Glaciology 39 (2004): 331–38. http://dx.doi.org/10.3189/172756404781813907.
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AbstractStatistical analyses are carried out, of the annual mean surface air temperature at occupied stations and automatic weather stations in the Antarctic and Southern and Pacific Oceans. The data are studied in four groupings: coastal Antarctica (excluding the Antarctic Peninsula), inland Antarctica, the Antarctic Peninsula and the Southern Ocean/Pacific Ocean islands. We find that within each of these four groupings the average trend indicates warming. For coastal Antarctica the trend is ∼0.8°C(100 a)–1. Inland, the results are less clear, but the mean trend is to a warming of ∼1.0°C(100 a)–1. For the Peninsula stations it is ∼4.4°C(100 a)–1, and for the ocean stations the average trend is ∼0.8°C(100 a)–1. The results indicate a reduction in the warming trend since our last analysis 6 years ago. While the Pinatubo (Philippines) volcanic eruption may have had some influence on this reduction in the warming rate, examination of the interannual variations in the temperature record shows variability has continued high since the recovery from any such effect. There has been a further period of cooler temperatures in coastal and inland Antarctica in that time, yet a warmer period in the Peninsula and ocean islands.
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Lu, C. C., and R. Williams. "Contribution to the biology of squid in the Prydz Bay region, Antarctica." Antarctic Science 6, no. 2 (June 1994): 223–29. http://dx.doi.org/10.1017/s0954102094000349.
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The teuthoid fauna of the Prydz Bay region of the Southern Ocean (Indian Ocean sector) has been studied based on the material collected from 1981–1991 using a rectangular midwater trawl (RMT-8), pelagic trawl (IYGPT), and bottom trawl. Eight species of squid have been recognized: Brachioteuthis sp., Kondakovia longimana, Bathyteuthis abyssicola, Psychroteuthis glacialis, Alluroteuthis antarcticus, Mastigoteuthis psychrophila, Mesonychoteuthis hamiltoni and Galiteuthis glacialis. Size frequency distribution, geographical and vertical distributions of each species as well as diets of common species are analysed. There is no evidence of a diel vertical migration but ontogenetic descent appears to occur in P. glacialis and G. glacialis. Antarctic krill, Euphausia superba and the Antarctic silverfish, Pleuragramma antarcticum are important prey for most species with cannibalism occurring in P. glacialis, A. antarcticus and M. hamiltoni. Equations for calculating total weight from mantle length, and mantle length and total weight from upper and lower rostral length are provided for B. abyssicola, P. glacialis, A. antarcticus, M. psychrophila, and G. glacialis.
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Long, Douglas J. "Quaternary colonization or Paleogene persistence?: historical biogeography of skates (Chondrichthyes: Rajidae) in the Antarctic ichthyofauna." Paleobiology 20, no. 2 (1994): 215–28. http://dx.doi.org/10.1017/s0094837300012690.
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Seven endemic species of skates (Chondrichthyes: Rajidae) represent the only family of elasmobranchs currently known to live in Antarctic continental waters. Many previous authors believed skates colonized Antarctic waters from Patagonia during interglacial periods in the Quaternary. However, recent fossil material collected from the middle Eocene La Meseta Formation of Seymour Island, Antarctic Peninsula, indicates that they may have persisted in Antarctic waters since the Paleogene. Additionally, oceanographic barriers present in the Neogene and Quaternary would have prevented dispersal from southern continents to Antarctica. A revised dispersal scenario, based on skate fossils, biology, paleogeography, and present centers of skate diversity, suggests that skates evolved in the western Tethys and North Boreal seas of western Europe in the Late Cretaceous and early Paleogene and emigrated into Antarctica during the early to middle Eocene via a dispersal corridor along the continental margins of the western Atlantic Ocean. Skates probably populated the Pacific Basin by passing from this dispersal corridor through the Arctic Ocean. Vicariant events, such as opening of the Drake Passage, the development of the Circum-Antarctic Current, and formation of deep and wide basins around Antarctica in the late Paleogene, created barriers that isolated some species of skates in Antarctica and prevented movement of other species of skates into Antarctica from northern areas. Skates are the only group of fishes known to have survived the Oligocene cooling of Antarctica that killed or extirpated the Paleogene ichthyofauna; they persisted by a combination of cold-tolerance, generalized diet, and unspecialized bathymetric and habitat preferences.
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Kusahara, Kazuya, and Kay I. Ohshima. "Kelvin Waves around Antarctica." Journal of Physical Oceanography 44, no. 11 (November 1, 2014): 2909–20. http://dx.doi.org/10.1175/jpo-d-14-0051.1.
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Abstract The Southern Ocean allows circumpolar structure and the Antarctic coastline plays a role as a waveguide for oceanic Kelvin waves. Under the cyclic conditions, the horizontal wavenumbers and frequencies for circumpolarly propagating waves are quantized, with horizontal wavenumbers 1, 2, and 3, corresponding to periods of about 32, 16, and 11 h, respectively. At these frequencies, westward-propagating signals are detected in sea level variation observed at Antarctic coastal stations. The occurrence frequency of westward-propagating signals far exceeds the statistical significance, and the phase speed of the observed signal agrees well with the theoretical phase speed of external Kelvin waves. Therefore, this study concludes that the observed, westward-propagating sea level variability is a signal of the external Kelvin waves of wavenumbers 1, 2, and 3 around Antarctica. A series of numerical model experiments confirms that Kelvin waves around Antarctica are driven by surface air pressure and that these waves are excited not only by local forcing over the Southern Ocean, but also by remote forcing over the Pacific Ocean. Sea level variations generated over the Pacific Ocean can travel to the western side of the South American coast and cross over Drake Passage to the Antarctic continent, constituting a part of the Kelvin waves around Antarctica.
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Bell, Robin E., and Helene Seroussi. "History, mass loss, structure, and dynamic behavior of the Antarctic Ice Sheet." Science 367, no. 6484 (March 19, 2020): 1321–25. http://dx.doi.org/10.1126/science.aaz5489.
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Antarctica contains most of Earth’s fresh water stored in two large ice sheets. The more stable East Antarctic Ice Sheet is larger and older, rests on higher topography, and hides entire mountain ranges and ancient lakes. The less stable West Antarctic Ice Sheet is smaller and younger and was formed on what was once a shallow sea. Recent observations made with several independent satellite measurements demonstrate that several regions of Antarctica are losing mass, flowing faster, and retreating where ice is exposed to warm ocean waters. The Antarctic contribution to sea level rise has reached ~8 millimeters since 1992. In the future, if warming ocean waters and increased surface meltwater trigger faster ice flow, sea level rise will accelerate.
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MACKENSEN, ANDREAS. "Changing Southern Ocean palaeocirculation and effects on global climate." Antarctic Science 16, no. 4 (November 30, 2004): 369–86. http://dx.doi.org/10.1017/s0954102004002202.
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Southern Ocean palaeocirculation is clearly related to the formation of a continental ice sheet on Antarctica and the opening of gateways between Antarctica and the Australian and South American continents. Palaeoenvironmental proxy records from Southern Ocean sediment cores suggest ice growth on Antarctica beginning by at least 40 million years (Ma) ago, and the opening of Tasmania–Antarctic and Drake Passages to deep-water flow around 34 and 31 ± 2 Ma, respectively. So, the Eocene/Oligocene transition appears to mark the initiation of the Antarctic Circumpolar Current and thus the onset of thermal isolation of Antarctica with a first major ice volume growth on East Antarctic. There is no evidence for a significant cooling of the deep ocean associated with this rapid (< 350 000 years) continental ice build-up. After a long phase with frequent ice sheets growing and decaying, in the middle Miocene at about 14 Ma, a re-establishment of an ice sheet on East Antarctica and the Pacific margin of West Antarctica was associated with an increased southern bottom water formation, and a slight cooling of the deep ocean, but with no permanent drop in atmospheric pCO2. During the late Pleistocene on orbital time scales a temporal correlation between changes in atmospheric pCO2 and proxy records of deep ocean temperatures, continental ice volume, sea ice extension, and deep-water nutrient contents is documented. I discuss hypotheses that call for a dominant control of glacial to interglacial atmospheric pCO2 variations by Southern Ocean circulation dynamics. Millennial to centennial climate variability is a global feature, but there is contrasting evidence from various palaeoclimate archives that indicate both interhemispheric synchrony and asynchrony. The role of the Southern Ocean, however, in triggering or modulating climate variability on these time scales only recently received some attention and is not yet adequately investigated.
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Chown, Steven L., and Cassandra M. Brooks. "The State and Future of Antarctic Environments in a Global Context." Annual Review of Environment and Resources 44, no. 1 (October 17, 2019): 1–30. http://dx.doi.org/10.1146/annurev-environ-101718-033236.
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Antarctica and the Southern Ocean comprise a critical part of the Earth System. Their environments are better understood than ever before, yet the region remains poorly considered among international agreements to improve the state of the global environment. In part the situation owes to isolated regional regulation within the Antarctic Treaty System, and in part to the dated notion that Antarctica and the Southern Ocean are well conserved and relatively free from human impact. Here we review growth in knowledge of Antarctic environments and anthropogenic pressures on them. We show that the region's unusual diversity is facing substantial local and globally mediated anthropogenic pressure, on a par with environments globally. Antarctic environmental management and regulation is being challenged to keep pace with the change. Much benefit can be derived from consideration of Antarctic environmental and resource management in the context of global agreements.
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Zhu, Jiangping, Aihong Xie, Xiang Qin, Bing Xu, and Yicheng Wang. "Assessment of Antarctic Amplification Based on a Reconstruction of Near-Surface Air Temperature." Atmosphere 14, no. 2 (January 20, 2023): 218. http://dx.doi.org/10.3390/atmos14020218.
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Polar amplification has been a research focus in climate research in recent decades. However, little attention has been paid to Antarctic amplification (AnA). We have examined the variations in annual and seasonal temperature over the Antarctic Ice Sheet and its amplification based on reconstruction covering the period 2002–2018. The results show the occurrence of annual and seasonal AnA, with an AnA index greater than 1.39 with seasonal differences, and that AnA is strong in the austral winter and spring. Moreover, AnA displays regional differences, with the greatest amplification occurring in East Antarctica, with an AnA index greater than 1.51, followed by West Antarctica. AnA is always absent in the Antarctic Peninsula. In addition, amplification in East Antarctica is most conspicuous in spring, which corresponds to the obvious warming in this season; and the spring amplification signal is weakest for West Antarctica. When considering the influence of the ocean, the AnA becomes obvious, compared to when only the land is considered. Southern Annular Mode (SAM), surface pressure and westerlies work together to affect the temperature change over Antarctica and AnA; and SAM and surface pressure are highly correlated with the temperature change over East Antarctica. The picture reflects the accelerated changes in Antarctic temperature.
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Storey, Bryan C., and Roi Granot. "Chapter 1.1 Tectonic history of Antarctica over the past 200 million years." Geological Society, London, Memoirs 55, no. 1 (2021): 9–17. http://dx.doi.org/10.1144/m55-2018-38.
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AbstractThe tectonic evolution of Antarctica in the Mesozoic and Cenozoic eras was marked by igneous activity that formed as a result of simultaneous continental rifting and subduction processes acting during the final stages of the southward drift of Gondwana towards the South Pole. For the most part, continental rifting resulted in the progressive disintegration of the Gondwana supercontinent from Middle Jurassic times to the final isolation of Antarctica at the South Pole following the Cenozoic opening of the surrounding ocean basins, and the separation of Antarctica from South America and Australia. The initial rifting into East and West Gondwana was proceeded by emplacement of large igneous provinces preserved in present-day South America, Africa and Antarctica. Continued rifting within Antarctica did not lead to continental separation but to the development of the West Antarctic Rift System, dividing the continent into the East and West Antarctic plates, and uplift of the Transantarctic Mountains. Motion between East and West Antarctica has been accommodated by a series of discrete rifting pulses with a westward shift and concentration of the motion throughout the Cenozoic leading to crustal thinning, subsidence, elevated heat flow conditions and rift-related magmatic activity. Contemporaneous with the disintegration of Gondwana and the isolation of Antarctica, subduction processes were active along the palaeo-Pacific margin of Antarctica recorded by magmatic arcs, accretionary complexes, and forearc and back-arc basin sequences. A low in magmatic activity between 156 and 142 Ma suggests that subduction may have ceased during this time. Today, following the gradual cessation of the Antarctic rifting and surrounding subduction, the Antarctic continent is situated close to the centre of a large Antarctic Plate which, with the exception of an active margin on the northern tip of the Antarctic Peninsula, is surrounded by active spreading ridges.
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Yu, Lejiang, Shiyuan Zhong, and Bo Sun. "The Climatology and Trend of Surface Wind Speed over Antarctica and the Southern Ocean and the Implication to Wind Energy Application." Atmosphere 11, no. 1 (January 16, 2020): 108. http://dx.doi.org/10.3390/atmos11010108.
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Surface wind trends and variability over Antarctica and the Southern Ocean and their implications to wind energy in the region are analyzed using the gridded ERA-Interim reanalysis data between 1979 and 2017 and the Self-Organizing Map (SOM) technique. In general, surface winds are stronger over the coastal regions of East Antarctica and the Transantarctic Mountains and weaker over the Ross and Ronne ice shelves and the Antarctic Peninsula; and stronger in winter and weaker in summer. Winds in the southern Indian and Pacific Oceans and along coastal regions exhibit a strong interannual variability that appears to be correlated to the Antarctic Oscillation (AAO) index. A significantly positive trend in surface wind speeds is found across most regions and about 20% and 17% of the austral autumn and summer wind trends, respectively, and less than 1% of the winter and spring wind trends may be explained by the trends in the AAO index. Except for the Antarctic Peninsula, Ronne and Ross ice shelves, and small areas in the interior East Antarctica, most of the continent is found to be suitable for the development of wind power.
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Ahn, In-Young, Francyne Elias-Piera, Sun-Yong Ha, Sergio Rossi, and Dong-U. Kim. "Seasonal Dietary Shifts of the Gammarid Amphipod Gondogeneia antarctica in a Rapidly Warming Fjord of the West Antarctic Peninsula." Journal of Marine Science and Engineering 9, no. 12 (December 17, 2021): 1447. http://dx.doi.org/10.3390/jmse9121447.
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The amphipod Gondogeneia antarctica is among the most abundant benthic organisms, and a key food web species along the rapidly warming West Antarctic Peninsula (WAP). However, little is known about its trophic strategy for dealing with the extreme seasonality of Antarctic marine primary production. This study, using trophic markers, for the first time investigated seasonal dietary shifts of G. antarctica in a WAP fjord. We analyzed δ13C and δ15N in G. antarctica and its potential food sources. The isotopic signatures revealed a substantial contribution of red algae to the amphipod diet and also indicated a significant contribution of benthic diatoms. The isotope results were further supported by fatty acid (FA) analysis, which showed high similarities in FA composition (64% spring–summer, 58% fall–winter) between G. antarctica and the red algal species. G. antarctica δ13C showed a small shift seasonally (−18.9 to −21.4‰), suggesting that the main diets do not change much year-round. However, the relatively high δ15N values as for primary consumers indicated additional dietary sources such as animal parts. Interestingly, G. antarctica and its potential food sources were significantly enriched with δ15N during the fall–winter season, presumably through a degradation process, suggesting that G. antarctica consumes a substantial portion of its diets in the form of detritus. Overall, the results revealed that G. antarctica relies primarily on food sources derived from benthic primary producers throughout much of the year. Thus, G. antarctica is unlikely very affected by seasonal Antarctic primary production, and this strategy seems to have allowed them to adapt to shallow Antarctic nearshore waters.
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Rubin, Jeff. "Train Oil and Snotters: Eating Antarctic Wild Foods." Gastronomica 3, no. 1 (2003): 37–57. http://dx.doi.org/10.1525/gfc.2003.3.1.37.
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People may no longer eat the wild foods of Antarctica, because the Antarctic Treaty's Protocol on Environmental Protection signed in 1991 prohibits even "disturbing" any wildlife, but there is a long history of living off the land in Antarctica and on the remote islands of the Southern Ocean. Visitors regularly ate seals, penguins and other seabirds, eggs, shellfish, and several unusual endemic plants. Fresh food was critical in avoiding scurvy, caused by a lack of Vitamin C. Local foods also occupied a prominent place on the table during Antarctic holidays such as Midwinter's Day.
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TAVARES, MARCOS, and GUSTAVO A. S. DE MELO. "Discovery of the first known benthic invasive species in the Southern Ocean: the North Atlantic spider crab Hyas araneus found in the Antarctic Peninsula." Antarctic Science 16, no. 2 (June 2004): 129–31. http://dx.doi.org/10.1017/s0954102004001877.
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The Southern Ocean around Antarctica is no longer free from invasive marine species. The North Atlantic spider crab Hyas araneus (Linnaeus, 1758) (Crustacea: Decapoda: Majidae) has been recorded for the first time from the Antarctic Peninsula. Isolated for at least 25 million years, the endemic Antarctic Southern Ocean marine fauna is now being exposed to human-mediated influx of exotic species. Invasive species and polar warming combined can foster the probability of arrival and colonization by non-indigenous species, with unpredictable consequences for the Antarctic marine biota.
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Bougamont, Marion, Elizabeth Hunke, and Slawek Tulaczyk. "Sensitivity of ocean circulation and sea-ice conditions to loss of West Antarctic ice shelves and ice sheet." Journal of Glaciology 53, no. 182 (2007): 490–98. http://dx.doi.org/10.3189/002214307783258440.
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AbstractWe use a global coupled ocean-sea ice model to test the hypothesis that the disintegration of the West Antarctic ice sheet (WAIS), or just its ice shelves, may modify ocean circulation and sea-ice conditions in the Southern Ocean. We compare the results of three model runs: (1) a control run with a standard (modern) configuration of landmask in West Antarctica, (2) a no-shelves run with West Antarctic ice shelves removed and (3) a no-WAIS run. In the latter two runs, up to a few million square kilometres of new sea surface area opens to sea-ice formation, causing the volume and extent of Antarctic sea-ice cover to increase compared with the control run. In general, near-surface waters are cooler around Antarctica in the no-shelves and no-WAIS model runs than in the control run, while warm intermediate and deep waters penetrate further south, increasing poleward heat transport. Varying regional responses to the imposed changes in landmask configuration are determined by the fact that Antarctic polynyas and fast ice develop in different parts of the model domain in each run. Model results suggest that changes in the extent of WAIS may modify oceanographic conditions in the Southern Ocean.
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Singh, Hansi K. A., Cecilia M. Bitz, and Dargan M. W. Frierson. "The Global Climate Response to Lowering Surface Orography of Antarctica and the Importance of Atmosphere–Ocean Coupling." Journal of Climate 29, no. 11 (May 20, 2016): 4137–53. http://dx.doi.org/10.1175/jcli-d-15-0442.1.
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Abstract A global climate model is used to study the effect of flattening the orography of the Antarctic Ice Sheet on climate. A general result is that the Antarctic continent and the atmosphere aloft warm, while there is modest cooling globally. The large local warming over Antarctica leads to increased outgoing longwave radiation, which drives anomalous southward energy transport toward the continent and cooling elsewhere. Atmosphere and ocean both anomalously transport energy southward in the Southern Hemisphere. Near Antarctica, poleward energy and momentum transport by baroclinic eddies strengthens. Anomalous southward cross-equatorial energy transport is associated with a northward shift in the intertropical convergence zone. In the ocean, anomalous southward energy transport arises from a slowdown of the upper cell of the oceanic meridional overturning circulation and a weakening of the horizontal ocean gyres, causing sea ice in the Northern Hemisphere to expand and the Arctic to cool. Comparison with a slab-ocean simulation confirms the importance of ocean dynamics in determining the climate system response to Antarctic orography. This paper concludes by briefly presenting a discussion of the relevance of these results to climates of the past and to future climate scenarios.
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Dixon, Daniel, Paul A. Mayewski, Susan Kaspari, Karl Kreutz, Gordon Hamilton, Kirk Maasch, Sharon B. Sneed, and Michael J. Handley. "A 200 year sulfate record from 16 Antarctic ice cores and associations with Southern Ocean sea-ice extent." Annals of Glaciology 41 (2005): 155–66. http://dx.doi.org/10.3189/172756405781813366.
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AbstractChemistry data from 16, 50–115m deep, sub-annually dated ice cores are used to investigate spatial and temporal concentration variability of sea-salt (ss) SO42– and excess (xs) SO42– over West Antarctica and the South Pole for the last 200 years. Low-elevation ice-core sites in western West Antarctica contain higher concentrations of SO42– as a result of cyclogenesis over the Ross Ice Shelf and proximity to the Ross Sea Polynya. Linear correlation analysis of 15 West Antarctic ice-core SO42– time series demonstrates that at several sites concentrations of ssSO42– are higher when sea-ice extent (SIE) is greater, and the inverse for xsSO42–. Concentrations of xsSO42– from the South Pole site (East Antarctica) are associated with SIE from the Weddell region, and West Antarctic xsSO42– concentrations are associated with SIE from the Bellingshausen–Amundsen–Ross region. The only notable rise of the last 200 years in xsSO42–, around 1940, is not related to SIE fluctuations and is most likely a result of increased xsSO42– production in the mid–low latitudes and/or an increase in transport efficiency from the mid–low latitudes to central West Antarctica. These high-resolution records show that the source types and source areas of ssSO42– and xsSO42– delivered to eastern and western West Antarctica and the South Pole differ from site to site but can best be resolved using records from spatial ice-core arrays such as the International Trans-Antarctic Scientific Expedition (ITASE).
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Wang, Hailong, Jeremy G. Fyke, Jan T. M. Lenaerts, Jesse M. Nusbaumer, Hansi Singh, David Noone, Philip J. Rasch, and Rudong Zhang. "Influence of sea-ice anomalies on Antarctic precipitation using source attribution in the Community Earth System Model." Cryosphere 14, no. 2 (February 4, 2020): 429–44. http://dx.doi.org/10.5194/tc-14-429-2020.
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Abstract. We conduct sensitivity experiments using a general circulation model that has an explicit water source tagging capability forced by prescribed composites of pre-industrial sea-ice concentrations (SICs) and corresponding sea surface temperatures (SSTs) to understand the impact of sea-ice anomalies on regional evaporation, moisture transport and source–receptor relationships for Antarctic precipitation in the absence of anthropogenic forcing. Surface sensible heat fluxes, evaporation and column-integrated water vapor are larger over Southern Ocean (SO) areas with lower SICs. Changes in Antarctic precipitation and its source attribution with SICs have a strong spatial variability. Among the tagged source regions, the Southern Ocean (south of 50∘ S) contributes the most (40 %) to the Antarctic total precipitation, followed by more northerly ocean basins, most notably the South Pacific Ocean (27%), southern Indian Ocean (16 %) and South Atlantic Ocean (11 %). Comparing two experiments prescribed with high and low pre-industrial SICs, respectively, the annual mean Antarctic precipitation is about 150 Gt yr−1 (or 6 %) more in the lower SIC case than in the higher SIC case. This difference is larger than the model-simulated interannual variability in Antarctic precipitation (99 Gt yr−1). The contrast in contribution from the Southern Ocean, 102 Gt yr−1, is even more significant compared to the interannual variability of 35 Gt yr−1 in Antarctic precipitation that originates from the Southern Ocean. The horizontal transport pathways from individual vapor source regions to Antarctica are largely determined by large-scale atmospheric circulation patterns. Vapor from lower-latitude source regions takes elevated pathways to Antarctica. In contrast, vapor from the Southern Ocean moves southward within the lower troposphere to the Antarctic continent along moist isentropes that are largely shaped by local ambient conditions and coastal topography. This study also highlights the importance of atmospheric dynamics in affecting the thermodynamic impact of sea-ice anomalies associated with natural variability on Antarctic precipitation. Our analyses of the seasonal contrast in changes of basin-scale evaporation, moisture flux and precipitation suggest that the impact of SIC anomalies on regional Antarctic precipitation depends on dynamic changes that arise from SIC–SST perturbations along with internal variability. The latter appears to have a more significant effect on the moisture transport in austral winter than in summer.
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Bengtson Nash, Susan Maria, Seanan Wild, Sara Broomhall, and Pernilla Bohlin-Nizzetto. "Brominated Flame Retardants in Antarctic Air in the Vicinity of Two All-Year Research Stations." Atmosphere 12, no. 6 (May 24, 2021): 668. http://dx.doi.org/10.3390/atmos12060668.
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Continuous atmospheric sampling was conducted between 2010–2015 at Casey station in Wilkes Land, Antarctica, and throughout 2013 at Troll Station in Dronning Maud Land, Antarctica. Sample extracts were analyzed for polybrominated diphenyl ethers (PBDEs), and the naturally converted brominated compound, 2,4,6-Tribromoanisole, to explore regional profiles. This represents the first report of seasonal resolution of PBDEs in the Antarctic atmosphere, and we describe conspicuous differences in the ambient atmospheric concentrations of brominated compounds observed between the two stations. Notably, levels of BDE-47 detected at Troll station were higher than those previously detected in the Antarctic or Southern Ocean region, with a maximum concentration of 7800 fg/m3. Elevated levels of penta-formulation PBDE congeners at Troll coincided with local building activities and subsided in the months following completion of activities. The latter provides important information for managers of National Antarctic Programs for preventing the release of persistent, bioaccumulative, and toxic substances in Antarctica.
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Zhu, Chenyu, Jiaxu Zhang, Zhengyu Liu, Bette L. Otto-Bliesner, Chengfei He, Esther C. Brady, Robert Tomas, et al. "Antarctic Warming during Heinrich Stadial 1 in a Transient Isotope-Enabled Deglacial Simulation." Journal of Climate 35, no. 22 (November 15, 2022): 3753–65. http://dx.doi.org/10.1175/jcli-d-22-0094.1.
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Abstract Heinrich Stadial 1 (HS1) was the major climate event at the onset of the last deglaciation associated with rapid cooling in Greenland and lagged, slow warming in Antarctica. Although it is widely believed that temperature signals were triggered in the Northern Hemisphere and propagated southward associated with the Atlantic meridional overturning circulation (AMOC), understanding how these signals were able to cross the Antarctic Circumpolar Current (ACC) barrier and further warm up Antarctica has proven particularly challenging. In this study, we explore the physical processes that lead to the Antarctic warming during HS1 in a transient isotope-enabled deglacial simulation iTRACE, in which the interpolar phasing has been faithfully reproduced. We show that the increased meridional heat transport alone, first through the ocean and then through the atmosphere, can explain the Antarctic warming during the early stage of HS1 without notable changes in the strength and position of the Southern Hemisphere midlatitude westerlies. In particular, when a reduction of the AMOC causes ocean warming to the north of the ACC, increased southward ocean heat transport by mesoscale eddies is triggered by steeper isopycnals to warm up the ocean beyond the ACC, which further decreases the sea ice concentration and leads to more absorption of insolation. The increased atmospheric heat then releases to the Antarctic primarily by a strengthening zonal wavenumber-3 (ZW3) pattern. Sensitivity experiments further suggest that a ∼4°C warming caused by this mechanism superimposed on a comparable warming driven by the background atmospheric CO2 rise is able to explain the total simulated ∼8°C warming in the West Antarctica during HS1.
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Pedro, J. B., T. D. van Ommen, S. O. Rasmussen, V. I. Morgan, J. Chappellaz, A. D. Moy, V. Masson-Delmotte, and M. Delmotte. "The last deglaciation: timing the bipolar seesaw." Climate of the Past Discussions 7, no. 1 (January 26, 2011): 397–430. http://dx.doi.org/10.5194/cpd-7-397-2011.
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Abstract. Precise information on the relative timing of north-south climate variations is a key to resolving questions concerning the mechanisms that force and couple climate changes between the hemispheres. We present a new composite record made from five well-resolved Antarctic ice core records that robustly represents the timing of regional Antarctic climate change during the last deglaciation. Using fast variations in global methane gas concentrations as time markers, the Antarctic composite is directly compared to Greenland ice core records, allowing a detailed mapping of the inter-hemispheric sequence of climate changes. Consistent with prior studies the synchronized records show that warming (and cooling) trends in Antarctica closely match cold (and warm) periods in Greenland on millennial timescales. For the first time, we also identify a sub-millennial component to the inter-hemispheric coupling: within the Antarctic Cold Reversal the strongest Antarctic cooling occurs during the pronounced northern warmth of the Bølling; warming then resumes in Antarctica during the Intra-Allerød Cold Period i.e. prior to the Younger Dryas stadial. There is little-to-no time lag between climate transitions in Greenland and opposing changes in Antarctica. Our results lend support to fast acting inter-hemispheric coupling mechanisms including recently proposed bipolar atmospheric teleconnections and/or rapid bipolar ocean teleconnections.
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Halanych, Kenneth M., and Andrew R. Mahon. "Challenging Dogma Concerning Biogeographic Patterns of Antarctica and the Southern Ocean." Annual Review of Ecology, Evolution, and Systematics 49, no. 1 (November 2, 2018): 355–78. http://dx.doi.org/10.1146/annurev-ecolsys-121415-032139.
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Antarctica is enormous, cold, remote, and particularly sensitive to climate change. Most biological research below 60°S has focused on the isolated nature of the biota and how organisms have adapted to the cold and ice. However, biogeographic patterns in Antarctica and the Southern Ocean, and the processes explaining how those patterns came about, still await adequate explanation. Both terrestrial and marine organisms have been influenced by climatic change (e.g., glaciation), physical phenomena (e.g., oceanic currents), and/or potential barriers to gene flow (e.g., steep thermal gradients). Whereas the Antarctic region contains diverse and complex marine communities, terrestrial systems tend to be comparatively simple with limited diversity. Here, we challenge the current dogma used to explain the diversity and biogeographic patterns present in the Antarctic. We assert that relatively modern processes within the last few million years, rather than geo-logical events that occurred in the Eocene and Miocene, account for present patterns of biodiversity in the region. Additionally, reproductive life history stages appear to have little influence in structuring genetic patterns in the Antarctic, as currents and glacial patterns are noted to be more important drivers of organismal patterns of distribution. Finally, we highlight the need for additional sampling, high-throughput genomic approaches, and broad, multinational cooperation for addressing outstanding questions of Antarctic biogeography and biodiversity.
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Pugh, P. J. A. "Have mites (Acarina: Arachnida) colonised Antarctica and the islands of the Southern Ocean via air currents?" Polar Record 39, no. 3 (June 26, 2003): 239–44. http://dx.doi.org/10.1017/s0032247403003097.
Full textAbstract:
Mites (Acarina: Arachnida) have not colonised Antarctica and the sub-Antarctic islands by ballooning on air currents. All acarine records from Pacific and Southern Ocean aerial plankton represent dead coastal (hemi)-edaphic species or phoretics dislodged from their flying insect hosts. The few sub-Antarctic records of mites capable of ‘ballooning’ on air currents are all verified as being attributed to anthropogenic introductions.
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Heinrich, Katharina. "Biological Prospecting in Antarctica – A Solution-Based Approach to Regulating the Collection and Use of Antarctic Marine Biodiversity by Taking the BBNJ Process into Account." Yearbook of Polar Law Online 12, no. 1 (December 13, 2021): 41–60. http://dx.doi.org/10.1163/22116427_012010005.
Full textAbstract:
Areas beyond national jurisdiction (ABNJ) are covering nearly two-thirds of the world’s oceans and are rich in biological diversity. These also include the Polar Regions, where marine organisms adapted to extreme environments and led to increased scientific interest and activities, including bioprospecting activities. As a result, marine biodiversity is increasingly threatened. Thus, the Convention on Biodiversity (CBD) was established to ensure the conservation and sustainable use of biodiversity but left ABNJ and bioprospecting activities widely unregulated. In Antarctica, for instance, bioprospecting has raised concerns, and the matter has been discussed since 2002. As a result, the United Nations General Assembly (UNGA) Resolution 69/292 concluded the establishment of a new international legally binding instrument (ILBI) on the conservation and sustainable use of marine biological diversity for ABNJ. However, the inclusion of the Antarctic Treaty Area remains unclear. In light of the current BBNJ negotiations, the Antarctic Treaty Consultative Meeting (ATCM) only acknowledges the Antarctic Treaty System (ATS) as the appropriate framework to regulate these activities in Antarctica. Further, it seems to aim for regulation under the ATS, if at all. Therefore, this paper discusses a solution-based approach for possible regulation of the collection and use of Antarctic marine biodiversity. The negotiations and achievements of the current BBNJ process will be taken into account, as they might provide support for the regulation of these issues in Antarctica and the Southern Ocean.
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E. Davis. Jr., William. "Heard Island: Southern Ocean Sentinel." Pacific Conservation Biology 13, no. 2 (2007): 145. http://dx.doi.org/10.1071/pc070145.
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Heard Island is one of the most remote places on earth. It is of volcanic origin (and currently volcanically active) on the submarine Kerguelen Plateau in the Southern Ocean, roughly 4 000 km south-west of Australia, 1 500 km from Antarctica, 3 750 km from Africa, and 7 500 km from India. The island is 367 km2 in area at latitude 53�S, south of the Antarctic Polar Front (Antarctic Convergence), is 70% covered with glaciers, and has a geologic, biologic and human history of substantial interest. Because of its remoteness, relative recent discovery (1853), and infrequent human visitation, it is pristine with no human-introduced plants or mammals.
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Kennicutt, M. C., S. L. Chown, J. J. Cassano, D. Liggett, L. S. Peck, R. Massom, S. R. Rintoul, et al. "A roadmap for Antarctic and Southern Ocean science for the next two decades and beyond." Antarctic Science 27, no. 1 (September 18, 2014): 3–18. http://dx.doi.org/10.1017/s0954102014000674.
Full textAbstract:
AbstractAntarctic and Southern Ocean science is vital to understanding natural variability, the processes that govern global change and the role of humans in the Earth and climate system. The potential for new knowledge to be gained from future Antarctic science is substantial. Therefore, the international Antarctic community came together to ‘scan the horizon’ to identify the highest priority scientific questions that researchers should aspire to answer in the next two decades and beyond. Wide consultation was a fundamental principle for the development of a collective, international view of the most important future directions in Antarctic science. From the many possibilities, the horizon scan identified 80 key scientific questions through structured debate, discussion, revision and voting. Questions were clustered into seven topics: i) Antarctic atmosphere and global connections, ii) Southern Ocean and sea ice in a warming world, iii) ice sheet and sea level, iv) the dynamic Earth, v) life on the precipice, vi) near-Earth space and beyond, and vii) human presence in Antarctica. Answering the questions identified by the horizon scan will require innovative experimental designs, novel applications of technology, invention of next-generation field and laboratory approaches, and expanded observing systems and networks. Unbiased, non-contaminating procedures will be required to retrieve the requisite air, biota, sediment, rock, ice and water samples. Sustained year-round access to Antarctica and the Southern Ocean will be essential to increase winter-time measurements. Improved models are needed that represent Antarctica and the Southern Ocean in the Earth System, and provide predictions at spatial and temporal resolutions useful for decision making. A co-ordinated portfolio of cross-disciplinary science, based on new models of international collaboration, will be essential as no scientist, programme or nation can realize these aspirations alone.
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Li, Xichen, David M. Holland, Edwin P. Gerber, and Changhyun Yoo. "Rossby Waves Mediate Impacts of Tropical Oceans on West Antarctic Atmospheric Circulation in Austral Winter." Journal of Climate 28, no. 20 (October 13, 2015): 8151–64. http://dx.doi.org/10.1175/jcli-d-15-0113.1.
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Abstract Recent studies link climate change around Antarctica to the sea surface temperature of tropical oceans, with teleconnections from the Pacific, Atlantic, and Indian Oceans making different contributions to Antarctic climate. In this study, the impacts of each ocean basin on the wintertime Southern Hemisphere circulation are identified by comparing simulation results using a comprehensive atmospheric model, an idealized dynamical core model, and a theoretical Rossby wave model. The results herein show that tropical Atlantic Ocean warming, Indian Ocean warming, and eastern Pacific cooling are all able to deepen the Amundsen Sea low located adjacent to West Antarctica, while western Pacific warming increases the pressure to the west of the international date line, encompassing the Ross Sea and regions south of the Tasman Sea. In austral winter, these tropical ocean basins work together linearly to modulate the atmospheric circulation around West Antarctica. Further analyses indicate that these teleconnections critically depend on stationary Rossby wave dynamics and are thus sensitive to the background flow, particularly the subtropical/midlatitude jet. Near these jets, wind shear is amplified, which strengthens the generation of Rossby waves. On the other hand, near the edges of the jets the meridional gradient of the absolute vorticity is also enhanced. As a consequence of the Rossby wave dispersion relationship, the jet edge may reflect stationary Rossby wave trains, serving as a waveguide. The simulation results not only identify the relative roles of each of the tropical ocean basins in the tropical–Antarctica teleconnection, but also suggest that a deeper understanding of teleconnections requires a better estimation of the atmospheric jet structures.
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Kriwoken, Lorne K., and John W. Williamson. "Hobart, Tasmania: Antarctic and Southern Ocean connections." Polar Record 29, no. 169 (April 1993): 93–102. http://dx.doi.org/10.1017/s0032247400023548.
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abstractThis paper describes the historical and contemporary associations between Hobart (Tasmania, Australia) and Antarctica and the Southern Ocean. This association is traced from the sealing and whaling industry, through early exploration and scientific expeditions, to contemporary issues of institutional and educational development and tourism. I is argued that this polar link has placed Hobart at the centre of some important Antarctic and Southern Ocean developments.
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Lavery, Charne. "Antarctica and Africa: Narrating alternate futures." Polar Record 55, no. 5 (September 2019): 347–50. http://dx.doi.org/10.1017/s0032247419000743.
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AbstractAfrica has been marginalised in the history of Antarctica, a politics of exclusion (with the exception of Apartheid South Africa) reflected unsurprisingly by a dearth of imaginative, cultural and literary engagement. But, in addition to paleontological and geophysical links, Antarctica has increasing interrelationship with Africa’s climactic future. Africa is widely predicted to be the continent worst affected by climate change, and Antarctica and its surrounding Southern Ocean are uniquely implicated as crucial mediators for changing global climate and currents, rainfall patterns, and sea level rise. This paper proposes that there are in fact several ways of imagining the far South from Africa in literary and cultural terms. One is to read against the grain for southern-directed perspectives in existing African literature and the arts, from southern coastlines looking south; another is to reexamine both familiar and new, speculative narratives of African weather – drought, flood and change – for their Antarctic entanglements. In the context of ongoing work on postcolonial Antarctica and calls to decolonise Antarctic studies – such readings can begin to bridge the Antarctica–Africa divide.
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Massé, Guillaume, Simon T. Belt, Xavier Crosta, Sabine Schmidt, Ian Snape, David N. Thomas, and Steven J. Rowland. "Highly branched isoprenoids as proxies for variable sea ice conditions in the Southern Ocean." Antarctic Science 23, no. 5 (June 27, 2011): 487–98. http://dx.doi.org/10.1017/s0954102011000381.
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AbstractConcentrations of a highly branched isoprenoid (HBI) diene determined in over 200 sediment samples from the Arctic co-vary with those of an HBI monoene (IP25) shown previously to be a sedimentary sea ice proxy for the Arctic. The same diene, but not monoene IP25, occurred in nine sea ice samples collected from various locations around Antarctica. The diene has been reported previously in Antarctic sea ice diatoms and the 13C isotopic compositions of the diene determined in two Antarctic sea ice samples were also consistent with an origin from sea ice diatoms (δ13C -5.7 to -8.5‰). In contrast, HBIs found in two Antarctic phytoplankton samples did not include the diene but comprised a number of tri- to pentaenes. In sediment samples collected near Adélie Land, East Antarctica, both the diene and the tri- to pentaenes often co-occurred. 13C isotopic compositions of the tri- to pentaenes in three sediment samples ranged from -35 to -42‰ whereas that of the diene in a sediment sample was -18‰. We propose the presence of this isotopically 13C enriched HBI diene in Antarctic sediments to be a useful proxy indicator for contributions of organic matter derived from sea ice diatoms. A ratio of the concentrations of diene/trienes might reflect the relative contributions of sea ice to phytoplanktonic inputs of organic matter to Antarctic sediments.
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SOLOVYOV, V. D., and V. G. BAKHMUTOV. "Marine geophysical research in the first Ukrainian Antarctic expeditions: historical outline and some results." Geology and Mineral Resources of World Ocean 18, no. 3 (2022): 44–62. http://dx.doi.org/10.15407/gpimo2022.03.044.
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The article is devoted of the 25th anniversary of the First Ukrainian Marine Antarctic Expedition (1997). The short history of development the marine geophysical study of the deep structures of the World Ocean and Antarctica in the S. I. Subbotin Institute of Geophysics (National Academy of sciences of Ukraine) is presented. Main focus is on the results obtained during the implementation of the «State research programs in Antarctica». The main patterns of geophysical anomalies and their spatiotemporal distributions in West Antarctica were investigated. The lithosphere deep structured geophysical models well corresponds with the evolution processes of the continental margin of the West Antarctica. The built-depth sections record the large-scale processes of the formation of the Drake Passage and the western part of the Scotia Sea as a result of the primary crust fragments’ transformation and the geodynamic evolution of the region located between South America and West Antarctica. Some results for the assessment of mineral resources and hydrocarbon potential of the continental margin structures of the NW area of the Antarctic Peninsula are presented.
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Pedro, J. B., T. D. van Ommen, S. O. Rasmussen, V. I. Morgan, J. Chappellaz, A. D. Moy, V. Masson-Delmotte, and M. Delmotte. "The last deglaciation: timing the bipolar seesaw." Climate of the Past 7, no. 2 (June 24, 2011): 671–83. http://dx.doi.org/10.5194/cp-7-671-2011.
Full textAbstract:
Abstract. Precise information on the relative timing of north-south climate variations is a key to resolving questions concerning the mechanisms that force and couple climate changes between the hemispheres. We present a new composite record made from five well-resolved Antarctic ice core records that robustly represents the timing of regional Antarctic climate change during the last deglaciation. Using fast variations in global methane gas concentrations as time markers, the Antarctic composite is directly compared to Greenland ice core records, allowing a detailed mapping of the inter-hemispheric sequence of climate changes. Consistent with prior studies the synchronized records show that warming (and cooling) trends in Antarctica closely match cold (and warm) periods in Greenland on millennial timescales. For the first time, we also identify a sub-millennial component to the inter-hemispheric coupling. Within the Antarctic Cold Reversal the strongest Antarctic cooling occurs during the pronounced northern warmth of the Bølling. Warming then resumes in Antarctica, potentially as early as the Intra-Allerød Cold Period, but with dating uncertainty that could place it as late as the onset of the Younger Dryas stadial. There is little-to-no time lag between climate transitions in Greenland and opposing changes in Antarctica. Our results lend support to fast acting inter-hemispheric coupling mechanisms, including recently proposed bipolar atmospheric teleconnections and/or rapid bipolar ocean teleconnections.
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Smith, Ben, Helen A. Fricker, Alex S. Gardner, Brooke Medley, Johan Nilsson, Fernando S. Paolo, Nicholas Holschuh, et al. "Pervasive ice sheet mass loss reflects competing ocean and atmosphere processes." Science 368, no. 6496 (April 30, 2020): 1239–42. http://dx.doi.org/10.1126/science.aaz5845.
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Quantifying changes in Earth’s ice sheets and identifying the climate drivers are central to improving sea level projections. We provide unified estimates of grounded and floating ice mass change from 2003 to 2019 using NASA’s Ice, Cloud and land Elevation Satellite (ICESat) and ICESat-2 satellite laser altimetry. Our data reveal patterns likely linked to competing climate processes: Ice loss from coastal Greenland (increased surface melt), Antarctic ice shelves (increased ocean melting), and Greenland and Antarctic outlet glaciers (dynamic response to ocean melting) was partially compensated by mass gains over ice sheet interiors (increased snow accumulation). Losses outpaced gains, with grounded-ice loss from Greenland (200 billion tonnes per year) and Antarctica (118 billion tonnes per year) contributing 14 millimeters to sea level. Mass lost from West Antarctica’s ice shelves accounted for more than 30% of that region’s total.
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Rignot, Eric. "Changes in ice dynamics and mass balance of the Antarctic ice sheet." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 364, no. 1844 (May 26, 2006): 1637–55. http://dx.doi.org/10.1098/rsta.2006.1793.
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The concept that the Antarctic ice sheet changes with eternal slowness has been challenged by recent observations from satellites. Pronounced regional warming in the Antarctic Peninsula triggered ice shelf collapse, which led to a 10-fold increase in glacier flow and rapid ice sheet retreat. This chain of events illustrated the vulnerability of ice shelves to climate warming and their buffering role on the mass balance of Antarctica. In West Antarctica, the Pine Island Bay sector is draining far more ice into the ocean than is stored upstream from snow accumulation. This sector could raise sea level by 1 m and trigger widespread retreat of ice in West Antarctica. Pine Island Glacier accelerated 38% since 1975, and most of the speed up took place over the last decade. Its neighbour Thwaites Glacier is widening up and may double its width when its weakened eastern ice shelf breaks up. Widespread acceleration in this sector may be caused by glacier ungrounding from ice shelf melting by an ocean that has recently warmed by 0.3 °C. In contrast, glaciers buffered from oceanic change by large ice shelves have only small contributions to sea level. In East Antarctica, many glaciers are close to a state of mass balance, but sectors grounded well below sea level, such as Cook Ice Shelf, Ninnis/Mertz, Frost and Totten glaciers, are thinning and losing mass. Hence, East Antarctica is not immune to changes.
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Delord, K., A. Kato, A. Tarroux, F. Orgeret, C. Cotté, Y. Ropert-Coudert, Y. Cherel, and S. Descamps. "Antarctic petrels ‘on the ice rocks’: wintering strategy of an Antarctic seabird." Royal Society Open Science 7, no. 4 (April 2020): 191429. http://dx.doi.org/10.1098/rsos.191429.
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There is a paucity of information on the foraging ecology, especially individual use of sea-ice features and icebergs, over the non-breeding season in many seabird species. Using geolocators and stable isotopes, we defined the movements, distribution and diet of adult Antarctic petrels Thalassoica antarctica from the largest known breeding colony, the inland Svarthamaren, Antarctica. More specifically, we examined how sea-ice concentration and free-drifting icebergs affect the distribution of Antarctic petrels. After breeding, birds moved north to the marginal ice zone (MIZ) in the Weddell sector of the Southern Ocean, following its northward extension during freeze-up in April, and they wintered there in April–August. There, the birds stayed predominantly out of the water (60–80% of the time) suggesting they use icebergs as platforms to stand on and/or to rest. Feather δ 15 N values encompassed one full trophic level, indicating that birds fed on various proportions of crustaceans and fish/squid, most likely Antarctic krill Euphausia superba and the myctophid fish Electrona antarctica and/or the squid Psychroteuthis glacialis . Birds showed strong affinity for the open waters of the northern boundary of the MIZ, an important iceberg transit area, which offers roosting opportunities and rich prey fields. The strong association of Antarctic petrels with sea-ice cycle and icebergs suggests the species can serve, year-round, as a sentinel of environmental changes for this remote region.
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Wang, Caixin, and Aike Beckmann. "Investigation of the impact of Antarctic ice-shelf melting in a global ice–ocean model (ORCA2-LIM)." Annals of Glaciology 46 (2007): 78–82. http://dx.doi.org/10.3189/172756407782871602.
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AbstractIce-shelf melting (ISM) removes heat from and injects fresh water into the adjacent ocean and contributes significantly to the freshwater balance and water mass formation in the Antarctic marginal seas. The thermodynamic interaction between ocean and ice shelf is a complicated process and usually not adequately included in the ocean–ice climate models. In this paper, the ISM from all major ice-shelf areas around Antarctica is added to a global coupled ice–ocean model ORCA2-LIM following the parameterization proposed by Beckmann and Goosse (2003). Using interannual forcing data from 1958 through 2000, the impact of ISM on Southern Ocean hydrography and sea-ice distribution is investigated. The model also shows global signatures of the Antarctic ISM.
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Kennicutt, M. C., Y. D. Kim, M. Rogan-Finnemore, S. Anandakrishnan, S. L. Chown, S. Colwell, D. Cowan, et al. "Delivering 21st century Antarctic and Southern Ocean science." Antarctic Science 28, no. 6 (October 21, 2016): 407–23. http://dx.doi.org/10.1017/s0954102016000481.
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AbstractThe Antarctic Roadmap Challenges (ARC) project identified critical requirements to deliver high priority Antarctic research in the 21st century. The ARC project addressed the challenges of enabling technologies, facilitating access, providing logistics and infrastructure, and capitalizing on international co-operation. Technological requirements include: i) innovative automated in situ observing systems, sensors and interoperable platforms (including power demands), ii) realistic and holistic numerical models, iii) enhanced remote sensing and sensors, iv) expanded sample collection and retrieval technologies, and v) greater cyber-infrastructure to process ‘big data’ collection, transmission and analyses while promoting data accessibility. These technologies must be widely available, performance and reliability must be improved and technologies used elsewhere must be applied to the Antarctic. Considerable Antarctic research is field-based, making access to vital geographical targets essential. Future research will require continent- and ocean-wide environmentally responsible access to coastal and interior Antarctica and the Southern Ocean. Year-round access is indispensable. The cost of future Antarctic science is great but there are opportunities for all to participate commensurate with national resources, expertise and interests. The scope of future Antarctic research will necessitate enhanced and inventive interdisciplinary and international collaborations. The full promise of Antarctic science will only be realized if nations act together.
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Turney, Chris S. M., Christopher J. Fogwill, Nicholas R. Golledge, Nicholas P. McKay, Erik van Sebille, Richard T. Jones, David Etheridge, et al. "Early Last Interglacial ocean warming drove substantial ice mass loss from Antarctica." Proceedings of the National Academy of Sciences 117, no. 8 (February 11, 2020): 3996–4006. http://dx.doi.org/10.1073/pnas.1902469117.
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The future response of the Antarctic ice sheet to rising temperatures remains highly uncertain. A useful period for assessing the sensitivity of Antarctica to warming is the Last Interglacial (LIG) (129 to 116 ky), which experienced warmer polar temperatures and higher global mean sea level (GMSL) (+6 to 9 m) relative to present day. LIG sea level cannot be fully explained by Greenland Ice Sheet melt (∼2 m), ocean thermal expansion, and melting mountain glaciers (∼1 m), suggesting substantial Antarctic mass loss was initiated by warming of Southern Ocean waters, resulting from a weakening Atlantic meridional overturning circulation in response to North Atlantic surface freshening. Here, we report a blue-ice record of ice sheet and environmental change from the Weddell Sea Embayment at the periphery of the marine-based West Antarctic Ice Sheet (WAIS), which is underlain by major methane hydrate reserves. Constrained by a widespread volcanic horizon and supported by ancient microbial DNA analyses, we provide evidence for substantial mass loss across the Weddell Sea Embayment during the LIG, most likely driven by ocean warming and associated with destabilization of subglacial hydrates. Ice sheet modeling supports this interpretation and suggests that millennial-scale warming of the Southern Ocean could have triggered a multimeter rise in global sea levels. Our data indicate that Antarctica is highly vulnerable to projected increases in ocean temperatures and may drive ice–climate feedbacks that further amplify warming.
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Jonkers, H. A. "Stratigraphy of Antarctic late Cenozoic pectinid-bearing deposits." Antarctic Science 10, no. 2 (June 1998): 161–70. http://dx.doi.org/10.1017/s0954102098000212.
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Antarctic late Cenozoic pectinid-bearing sedimentary strata are chiefly confined to localities in the northern part of the Antarctic Peninsula, in the McMurdo Sound area, and Marine Plain, East Antarctica. Ages of these deposits range from Oligocene to Holocene. Chlamys-like scallops, which are absent from today's Southern Ocean, thrived in Antarctic waters during both glacial and interglacial episodes, but disappeared during the Late Pliocene. Their extinction is believed to result from the combined effects of increased carbonate solubility, habitat loss and limitations in food availability, associated with major cooling.
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Chaturvedi, Sanjay. "Antarctica and the United Nations." India Quarterly: A Journal of International Affairs 42, no. 1 (January 1986): 1–26. http://dx.doi.org/10.1177/097492848604200101.
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During the 200-odd years, since the circumnavigation of the Antarctica by-Captain James Cook (1772–1775), international interest in the continent has grown to such an extent that the frozen Antarctica is now at the centre of a heated political debate. The prophecy of Captain Cook that the world would derive no profit out of it, seems to be proving wrong. Antarctica has now ceased to be merely the most significant ‘natural laboratory’ and the site of important scientific experiments, it has become, under the Antarctic Treaty of 1959, a subject of ‘innovative political experiment’ in multilateral administration.1 The surrounding oceans, where seals and whales were once-recklessly exploited, today harbour a new and fast growing fishery of immense potential,2 while the prospect of offshore oil and gas exploitation lies on the horizon. With the tantalising speculations regarding the existence of more than hundred onland minerals in Antarctica (including gold, copper, lithium and uranium), it is only natural that an increasing number of states should' take interest in this so far unnoticed mine.3 Divergence of national interests, perceptions and positions within the-Antarctica Treaty System in regard to who owns the Antarctic audits: resources—particularly between the Antarctica claimants and the non-claimants—has always led to tensions, latent as well as manifest, within the Treaty System; recently a series of new developments like the United Nations' involvement in the Antarctic question have added to the complexity of the Antarctic political scenario. They have serious future implications for the delicate political equilibrium so far maintained on the continent under the Antarctic Treaty. The questions asked today are: Who owns the Antarctic and how significant are the benefits To be derived out of it? Who is to profit from them? and To what extent the possible uses of Antarctica are-compatible with each other? The essay purports to critically examine, in a historical perspective, the nature, scope and implications of the interaction between the United Nations and the Antarctic Treaty System. While taking note of the earlier attempts made to make possible a UN control of Antarctica, the Antarctic Treaty of 1959 and the functioning thereof during the ‘sixties’ and ‘seventies’, we shall focus our attention on the recent endeavour of some countries to involve the United Nations in the Antarctic Question. The study would include, of course, the nature and scope of the United Nations study of theQuestion of Antarctica ( November 1984) and the ensuing discussions. Thus we shall examine the perceptions of various states, and of the desirability and extent of the role UN might play in Antarctica. We shall also take a special note of India's stand in this regard.
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Davis, W. Jackson, Peter J. Taylor, and W. Barton Davis. "The Origin and Propagation of the Antarctic Centennial Oscillation." Climate 7, no. 9 (September 17, 2019): 112. http://dx.doi.org/10.3390/cli7090112.
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The Antarctic Centennial Oscillation (ACO) is a paleoclimate temperature cycle that originates in the Southern Hemisphere, is the presumptive evolutionary precursor of the contemporary Antarctic Oscillation (AAO), and teleconnects to the Northern Hemisphere to influence global temperature. In this study we investigate the internal climate dynamics of the ACO over the last 21 millennia using stable water isotopes frozen in ice cores from 11 Antarctic drill sites as temperature proxies. Spectral and time series analyses reveal that ACOs occurred at all 11 sites over all time periods evaluated, suggesting that the ACO encompasses all of Antarctica. From the Last Glacial Maximum through the Last Glacial Termination (LGT), ACO cycles propagated on a multicentennial time scale from the East Antarctic coastline clockwise around Antarctica in the streamline of the Antarctic Circumpolar Current (ACC). The velocity of teleconnection (VT) is correlated with the geophysical characteristics of drill sites, including distance from the ocean and temperature. During the LGT, the VT to coastal sites doubled while the VT to inland sites decreased fourfold, correlated with increasing solar insolation at 65°N. These results implicate two interdependent mechanisms of teleconnection, oceanic and atmospheric, and suggest possible physical mechanisms for each. During the warmer Holocene, ACOs arrived synchronously at all drill sites examined, suggesting that the VT increased with temperature. Backward extrapolation of ACO propagation direction and velocity places its estimated geographic origin in the Southern Ocean east of Antarctica, in the region of the strongest sustained surface wind stress over any body of ocean water on Earth. ACO period is correlated with all major cycle parameters except cycle symmetry, consistent with a forced, undamped oscillation in which the driving energy affects all major cycle metrics. Cycle period and symmetry are not discernibly different for the ACO and AAO over the same time periods, suggesting that they are the same climate cycle. We postulate that the ACO/AAO is generated by relaxation oscillation of Westerly Wind velocity forced by the equator-to-pole temperature gradient and propagated regionally by identified air-sea-ice interactions.
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Dahe, Qin, Paul A. Mayewski, Ren Jiawen, Xiao Cunde, and Sun Junying. "The Weddell Sea region: an important precipitation channel to the interior of the Antarctic ice sheet as revealed by glaciochemical investigation of surface snow along the longest trans-Antarctic route." Annals of Glaciology 29 (1999): 55–60. http://dx.doi.org/10.3189/172756499781821012.
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AbstractGlaciochemical analysis of surface snow samples, collected along a profile crossing the Antarctic ice sheet from the Larsen Ice Shelf, Antarctic Peninsula, via the Antarctic Plateau through South Pole, Vostok and Komsomolskaya to Mirny station (at the east margin of East Antarctica), shows that the Weddell Sea region is an important channel for air masses to the high plateau of the Antarctic ice sheet (>2000 m a.s.l.). This opinion is supported by the following. (1) The fluxes of sea-salt ions such as Na+, Mg2 + and CF display a decreasing trend from the west to the east of interior Antarctica. In |eneral, as sea-salt aerosols are injected into the atmosphere over the Antarctic ice sheet from the Weddell Sea, large aerosols tend to decrease. For the inland plateau, few large particles of sea-salt aerosol reach the area, and the sea-salt concentration levels are low (2) The high altitude of the East Antarctic plateau, as well as the polar cold high-pressure system, obstruct the intrusive air masses mainly from the South Indian Ocean sector. (3) For the coastal regions of the East Antarctic ice sheet, the elevation rises to 2000 m over a distance from several to several tens of km. High concentrations of sea salt exist in snow in East Antarctica but are limited to a narrow coastal zone. (4) Fluxes of calcium and non-sea-salt sulfate in snow from the interior plateau do not display an eastward-decreasing trend. Since calcium is mainly derived from crustal sources, and nssSO42- is a secondary aerosol, this again confirms that the eastward-declining tendency of sea-salt ions indicates the transfer direction of precipitation vapor.
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Marshall, John, Kyle C. Armour, Jeffery R. Scott, Yavor Kostov, Ute Hausmann, David Ferreira, Theodore G. Shepherd, and Cecilia M. Bitz. "The ocean's role in polar climate change: asymmetric Arctic and Antarctic responses to greenhouse gas and ozone forcing." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 372, no. 2019 (July 13, 2014): 20130040. http://dx.doi.org/10.1098/rsta.2013.0040.
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In recent decades, the Arctic has been warming and sea ice disappearing. By contrast, the Southern Ocean around Antarctica has been (mainly) cooling and sea-ice extent growing. We argue here that interhemispheric asymmetries in the mean ocean circulation, with sinking in the northern North Atlantic and upwelling around Antarctica, strongly influence the sea-surface temperature (SST) response to anthropogenic greenhouse gas (GHG) forcing, accelerating warming in the Arctic while delaying it in the Antarctic. Furthermore, while the amplitude of GHG forcing has been similar at the poles, significant ozone depletion only occurs over Antarctica. We suggest that the initial response of SST around Antarctica to ozone depletion is one of cooling and only later adds to the GHG-induced warming trend as upwelling of sub-surface warm water associated with stronger surface westerlies impacts surface properties. We organize our discussion around ‘climate response functions’ (CRFs), i.e. the response of the climate to ‘step’ changes in anthropogenic forcing in which GHG and/or ozone-hole forcing is abruptly turned on and the transient response of the climate revealed and studied. Convolutions of known or postulated GHG and ozone-hole forcing functions with their respective CRFs then yield the transient forced SST response (implied by linear response theory), providing a context for discussion of the differing warming/cooling trends in the Arctic and Antarctic. We speculate that the period through which we are now passing may be one in which the delayed warming of SST associated with GHG forcing around Antarctica is largely cancelled by the cooling effects associated with the ozone hole. By mid-century, however, ozone-hole effects may instead be adding to GHG warming around Antarctica but with diminished amplitude as the ozone hole heals. The Arctic, meanwhile, responding to GHG forcing but in a manner amplified by ocean heat transport, may continue to warm at an accelerating rate.
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Tepper, Rohan, and Marcus Haward. "The development of Malaysia's position on Antarctica: 1982 to 2004." Polar Record 41, no. 2 (April 2005): 113–24. http://dx.doi.org/10.1017/s0032247405004262.
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This paper examines the development of Malaysia's position on the ‘Question of Antarctica’ and its relationship to the Antarctic Treaty System (ATS). Malaysia's challenges to, and criticisms of, the Antarctic Treaty Consultative Parties (ATCPs) are mapped from 1982 to 2004, indicating a shift from challenging the ATS to engagement with the ATCPs. The paper highlights how Malaysia's position on the ‘Question of Antarctica’ reflected a mix between domestic political concerns and its international and regional interests. The mix between domestic and international interests is reflected in the ongoing involvement of Malaysian Prime Minister Mahathir bin Mohamad, including his retirement in 2003, in shaping Malaysia's position, from initiating the challenge to the ATS in 1982 to recommending that Malaysia join the ATS in 2004. Mahathir's domestic agenda, most notably through Malaysia's ‘Vision 2020’ development program is identified as providing an impetus for change, increasing Malaysian scientific interest in Antarctica and the Southern Ocean.
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Basher, Zeenatul, and Mark J. Costello. "The past, present and future distribution of a deep-sea shrimp in the Southern Ocean." PeerJ 4 (February 23, 2016): e1713. http://dx.doi.org/10.7717/peerj.1713.
Full textAbstract:
Shrimps have a widespread distribution across the shelf, slope and seamount regions of the Southern Ocean. Studies of Antarctic organisms have shown that individual species and higher taxa display different degrees of sensitivity and adaptability in response to environmental change. We use species distribution models to predict changes in the geographic range of the deep-sea Antarctic shrimpNematocarcinus lanceopesunder changing climatic conditions from the Last Glacial Maximum to the present and to the year 2100. The present distribution range indicates a pole-ward shift of the shrimp population since the last glaciation. This occurred by colonization of slopes from nearby refugia located around the northern part of Scotia Arc, southern tip of South America, South Georgia, Bouvet Island, southern tip of the Campbell plateau and Kerguelen plateau. By 2100, the shrimp are likely to expand their distribution in east Antarctica but have a continued pole-ward contraction in west Antarctica. The range extension and contraction process followed by the deep-sea shrimp provide a geographic context of how other deep-sea Antarctic species may have survived during the last glaciation and may endure with projected changing climatic conditions in the future.
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BELLAN-SANTINI, DENISE, and JEAN-CLAUDE DAUVIN. "Haploops antarctica n. sp. (Crustacea: Gammaridea: Ampeliscidae): the first species of the genus Haploops from the Southern Antarctic Ocean." Zootaxa 1961, no. 1 (December 10, 2008): 26–36. http://dx.doi.org/10.11646/zootaxa.1961.1.3.
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Haploops antarctica n. sp. is described based on an female adult collected in the Antarctic peninsula (Bellingshausen Sea). This is the first species in the genus Haploops, which is a genus of generally deep boreal amphipods, to be found in the Southern Antarctic Ocean. Morphological characteristics that distinguish this new species from its congeners are the antenna formula A1>pedA2, the A1 and A2 < body length, the lobe of pereopod 7 expanded and densely setose, and the presence of one apical spine and one seta on the telson. In this paper, the new species is fully described and compared with related species; the relationship between H. antarctica and the geographical distribution of the genus is discussed; and a complete key of the 18 valid species in the genus Haploops is given.
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Romanov, P. Yu, and N. A. Romanova. "SEA-LEVEL PRESSURE TRENDS IN THE SOUTHERN OCEAN AND ANTARCTICA FROM REANALYSIS AND IN SITU DATA." Journal of Oceanological Research 49, no. 4 (December 30, 2021): 63–85. http://dx.doi.org/10.29006/1564-2291.jor-2021.49(4).3.
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Trends in the mean sea-level pressure (SLP) in Antarctica in the last four decades (1980– 2020) have been examined using in situ observations and reanalysis data. The analysis involved time series of monthly mean, season-mean and yearly-mean values of the SLP derived from four reanalysis datasets, NCEP/NCAR, ERA5, JRA55, MERRA2, and from surface observations acquired from the Reference Antarctic Data for Environmental Research (READER) dataset. With this data we have evaluated the trends, characterized their seasonal peculiarities and variation across the high-latitude region of the Southern Hemisphere. The results of the analysis confirmed the dominance of decreasing trends in the annual mean SLP in Antarctica. Larger negative trends were found in the Western Antarctica with the most pronounced pressure drop in the South Pacific. The long-term decrease in the annual mean SLP in Antarctica was due to strong negative pressure trends in the austral summer and fall season whereas in winter and in spring the trends turn to mixed and mostly positive. The comparison of multiyear time series of SLP reanalysis data with in situ observations at Antarctic stations revealed a considerable overestimate of negative SLP trends in the NCEP/NCAR dataset. Among the four examined reanalysis datasets, ERA5 provided the best agreement with the station data on the annual mean and monthly mean SLP trend values.
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Mayewski, Paul A., Kirk A. Maasch, James W. C. White, Eric J. Steig, Eric Meyerson, Ian Goodwin, Vin I. Morgan, et al. "A 700 year record of Southern Hemisphere extratropical climate variability." Annals of Glaciology 39 (2004): 127–32. http://dx.doi.org/10.3189/172756404781814249.
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AbstractAnnually dated ice cores from West and East Antarctica provide proxies for past changes in atmospheric circulation over Antarctica and portions of the Southern Ocean, temperature in coastal West and East Antarctica, and the frequency of South Polar penetration of El Niño events. During the period AD 1700–1850, atmospheric circulation over the Antarctic and at least portions of the Southern Hemisphere underwent a mode switch departing from the out-of-phase alternation of multi-decadal long phases of EOF1 and EOF2 modes of the 850 hPa field over the Southern Hemisphere (as defined in the recent record by Thompson and Wallace, 2000; Thompson and Solomon, 2002) that characterizes the remainder of the 700 year long record. From AD 1700 to 1850, lower-tropospheric circulation was replaced by in-phase behavior of the Amundsen Sea Low component of EOF2 and the East Antarctic High component of EOF1. During the first phase of the mode switch, both West and East Antarctic temperatures declined, potentially in response to the increased extent of sea ice surrounding both regions. At the end of the mode switch, West Antarctic coastal temperatures rose and East Antarctic coastal temperatures fell, respectively, to their second highest and lowest of the record. Polar penetration of El Niño events increased during the mode switch. The onset of the AD 1700–1850 mode switch coincides with the extreme state of the Maunder Minimum in solar variability. Late 20th-century West Antarctic coastal temperatures are the highest in the record period, and East Antarctic coastal temperatures close to the lowest. Since AD 1700, extratropical regions of the Southern Hemisphere have experienced significant climate variability coincident with changes in both solar variability and greenhouse gases.
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Shemesh, A., L. H. Burckle, and P. N. Froelich. "Dissolution and Preservation of Antarctic Diatoms and the Effect on Sediment Thanatocoenoses." Quaternary Research 31, no. 2 (March 1989): 288–308. http://dx.doi.org/10.1016/0033-5894(89)90010-0.
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AbstractComparison of Southern Ocean diatom populations from (i) surface ocean production, (ii) underlying Antarctic sediments, and (iii) laboratory dissolution experiments demonstrates that dissolution can account for the temporal and spatial variations in sedimentary diatom assemblages observed in Southern Ocean sediments. Increasing dissolution causes relative depletions in N. kerguelensis (K), enrichments in T. lentiginosa (L), and slight enrichments in E. antarctica (A). This reflects the relative susceptibility to dissolution of the three species that dominate Antarctic sediments. We have devised a preservation index for the Southern Ocean based on the ratio K/(K + L) to estimate relative extents of dissolution and applied it to natural assemblages. Holocene Southern Ocean sediments display increasing opal preservation toward higher latitudes, but south of the Antarctic Polar Front preservation decreases in the order: well preserved = SE Indian > S. Atlantic ∼ SW Indian > SE Pacific = poorly preserved. Dissolution also accounts for the pattern of diatom assemblages in the last glacial maximum (LGM) sediments of the Indian and Pacific sectors, but in the Atlantic, increased E. antarctica abundances at LGM must have resulted from an increase in surface ocean production of this species. Holocene and LGM diatoms in Atlantic and Pacific sector sediments are equally well preserved, but in the Indian sectors, Holocene sediments are better preserved than those of LGM age. Paleoceanographic and paleoclimatic transfer functions derived from factor analyses of variations in the sedimentary abundances of these three diatoms have ignored the effects of differential dissolution on thanatocoenosis and thus should be interpreted with caution.