Some Results of the British Antarctic Expedition, 1907-9

Shackleton, Ernest

doi:10.2307/1777278

Cited by 8 publications

(3 citation statements)

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“…Farther downstream, snow-covered crevasses are rotated to downstream-pointing directions and experience compression orthogonal to their trace. The first direct measurement of ice shelf motion was made in this area, when members of Shackletons’ Nimrod Expedition remeasured the position of ‘depot A’, left by the 1901–1904 British National Antarctic Expedition and found it to have moved about 500 yards a –1 (457 m a –1 ) over the 6.5-year interval (Shackleton, 1909; Debenham, 1948). The measurement was made by triangulation using the depot's original alignment with two peaks on the bluff.…”

Section: Province Map Of the Rismentioning

confidence: 99%

Structural provinces of the Ross Ice Shelf, Antarctica

et al. 2017

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ABSTRACT. The surface of the Ross Ice Shelf (RIS) is textured by flow stripes, crevasses and other features related to ice flow and deformation. Here, moderate resolution optical satellite images are used to map and classify regions of the RIS characterized by different surface textures. Because the textures arise from ice deformation, the map is used to identify structural provinces with common deformation history. We classify four province types: regions associated with large outlet glaciers, shear zones, extension downstream of obstacles and suture zones between provinces with different upstream sources. Adjacent provinces with contrasting histories are in some locations deforming at different rates, suggesting that our province map is also an ice fabric map. Structural provinces have more complicated shapes in the part of the ice shelf fed by West Antarctic ice streams than in the part fed by outlet glaciers from the Transantarctic Mountains. The map may be used to infer past variations in stress conditions and flow events that cannot be inferred from flow traces alone.

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Section: Province Map Of the Rismentioning

confidence: 99%

Structural provinces of the Ross Ice Shelf, Antarctica

et al. 2017

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“…Bdelloids were among the first microscopic animals found and studied in Antarctica (Murray, 1910); even Shackleton noted their ability to withstand the harsh environmental conditions (Shackleton, 1909). Yet, desiccation and freezing tolerance, allowing passive dispersal in bdelloids, are not unique to Antarctic species (Kaczmarek et al, 2019).…”

Section: Introductionmentioning

confidence: 99%

Comparative phylogeography reveals consistently shallow genetic diversity in a mitochondrial marker in Antarctic bdelloid rotifers

Cakil

Garlasché

Iakovenko

et al. 2021

Journal of Biogeography

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Aim The long history of isolation of the Antarctic continent, coupled with the harsh ecological conditions of freezing temperatures, could affect the patterns of genetic diversity in the organisms living there. We aim (a) to test whether such pattern can be seen in a mitochondrial marker of bdelloid rotifers, a group of microscopic aquatic and limno‐terrestrial animals and (b) to speculate on the potential mechanisms driving the pattern. Location Focus on Antarctica. Taxon Rotifera Bdelloidea. Methods We analysed different metrics of genetic diversity, also spatially explicit ones, including number of haplotypes, accumulation curves, genetic distances, time to the most recent common ancestor, number of independently evolving units from DNA taxonomy, strength of the correlation between geographical and genetic distances, population genetics neutrality and differentiation indices, potential historical processes, obtained from an extensive sample of cytochrome oxidase subunit I (COI) sequences obtained from bdelloid rotifers. We included 2242 individuals from 23 species in a comparison between Antarctic and non‐Antarctic taxa, correcting for sample size directly in the analyses and then by confirming the results also using only a restricted dataset of nine well‐sampled species. Results Antarctic species had consistently lower genetic diversity and potential younger relative age than non‐Antarctic species, even if they were similar in sample size, geographical extent, neutrality and differentiation indices, and correlation between genetic and geographical distances. Main conclusions The extensive survey of genetic diversity in one mitochondrial marker in Antarctic bdelloids supports previous suggestions from other organisms that the origin and maintenance of terrestrial Antarctic fauna are different from those of other continents. Such differences could be speculated to be due, in the case of bdelloid rotifers, to the more recent origin of the species living there in comparison to non‐Antarctic species.

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“…The early maps of Scott (1905) and Shackleton (1909) indicate that Cape Chocolate and the island berg were connected and that the edge of the Ross Ice Shelf was located at or just north of Cape Chocolate during their explorations (Fig. 1).…”

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confidence: 99%

Observations on Submerged Glacial Ice in McMurdo Sound, Antarctica

1978

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Several large submerged ice masses are described from along western McMurdo Sound, Antarctica. The most important discovery is that Cape Chocolate and the adjacent island that form Salmon Bay are large, grounded ice masses mounted with morainal sediment. Both features are probably remnants of a past expansion of the Ross Ice Shelf. As such, their strata and potential temporal markers may help to unravel the glacial geological chronology of McMurdo Sound. The island was connected to Cape Chocolate during the early British Antarctic expeditions and split away between 1908 and 1956. Large sections of the Ross Ice Shelf have broken out along western McMurdo Sound several times since 1908. Ice walls grounded in shallow water were only observed near large receding ice masses. The location of these walls also corresponds to the recent calving pattern of the Ross Ice Shelf.

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Some Results of the British Antarctic Expedition, 1907-9

Cited by 8 publications

References 0 publications

Structural provinces of the Ross Ice Shelf, Antarctica

Structural provinces of the Ross Ice Shelf, Antarctica

Comparative phylogeography reveals consistently shallow genetic diversity in a mitochondrial marker in Antarctic bdelloid rotifers

Observations on Submerged Glacial Ice in McMurdo Sound, Antarctica

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