Extensive colonization of volcanic ash by an unusual form of Peltigera didactyla at Deception Island, maritime Antarctic

2005 ◽  
Vol 37 (4) ◽  
pp. 367-368 ◽  
Author(s):  
Ronald I. Lewis-Smith
Keyword(s):  
Volcanic Ash ◽  
Deception Island ◽  
Maritime Antarctic ◽  
Cosmopolitan Distribution ◽  
Orkney Islands ◽  
Signy Island ◽  
Unusual Form ◽  
South Orkney Islands ◽  
The Antarctic

Peltigera didactyla (With.) J. R. Laundon has a cosmopolitan distribution, but in the Antarctic it is very restricted and is nowhere common or abundant, occurring at a number of sites in the northern maritime Antarctic extending to 65°S (Øvstedal & Lewis-Smith, 2001). Within its Antarctic distribution it appears to be most frequent on Signy Island, South Orkney Islands. Typically, this species grows as small colonies amongst mosses in relatively dry, gravelly, sheltered habitats, forming aggregations of lobed sorediate thalli up to c. 10–15 (rarely to c. 25) cm diameter.

The terrestrial invertebrate fauna of the Maritime Antarctic

1967 ◽  
Vol 252 (777) ◽  
pp. 261-278 ◽  
Keyword(s):  
Limiting Factor ◽  
Maritime Antarctic ◽  
Invertebrate Fauna ◽  
Orkney Islands ◽  
Signy Island ◽  
South Orkney Islands ◽  
Terrestrial Habitats ◽  
Community Variation ◽  
The Antarctic ◽  
Basic Similarity

During the period from 18 January to 31 M arch 1964 the author was able to visit certain islands on the Scotia Ridge and parts of the Antarctic Peninsula. Apart from South Georgia, all the areas lie within the Maritime Antarctic region (Holdgate 1964). At each locality an attempt was made to ascertain the composition of the meiofauna from as many terrestrial habitats as possible and, when time permitted, quantitative sampling was carried out. During the previous two years a similar but more detailed study was carried out at Signy Island, South Orkney Islands, but the bulk of these data will be presented elsewhere. Figure 32 shows all the areas visited with the month and number of quantitative samples taken. It was only possible to spend a few hours at certain localities. The Maritime Antarctic is, by definition (Holdgate 1964), a region bounded by isotherms and supporting a limited but typical vegetation. The types of plant communities have already been discussed (Longton, this Discussion, p. 213) and it is clear that whilst a considerable amount of species and community variation exists there is a basic similarity throughout the region. This general uniformity of climate and vegetation would together appear to offer a similar set of terrestrial habitat conditions. If dispersal were not a limiting factor, one would also expect the invertebrate fauna of such habitats to exhibit a uniform pattern. In fact it does not.

A fern cultured from Antarctic glacier detritus

2013 ◽  
Vol 26 (4) ◽  
pp. 341-344 ◽  
Author(s):  
R.I. Lewis Smith
Keyword(s):  
Maritime Antarctic ◽  
Orkney Islands ◽  
Ice Cap ◽  
Signy Island ◽  
South Orkney Islands ◽  
Mode Of Transport

AbstractA fem, Elaphoglossum hybridum (Bory) Brack., has been cultured from mineral sediment in cryoconite holes in the ice cap of Signy Island, South Orkney Islands. Its provenance, mode of transport to its Maritime Antarctic destination and the significance of viable exotic propagules as potential colonists are discussed.

The cryptostigmatid mite Halozetes belgicae (Michael) in the maritime Antarctic

1991 ◽  
Vol 3 (1) ◽  
pp. 53-59 ◽  
Author(s):  
L.B. Minto ◽  
G.J. Shepherd ◽  
M.B. Usher
Keyword(s):  
South Shetland Islands ◽  
Maritime Antarctic ◽  
The South ◽  
Macquarie Island ◽  
Shetland Islands ◽  
Orkney Islands ◽  
South Orkney Islands ◽  
South Sandwich Islands ◽  
The Antarctic ◽  
Morphometrical Study

Halozetes belgicae is distributed widely in the Subantarctic and maritime Antarctic, with subspecies described from Macquarie Island and the South Sandwich Islands. A morphometrical study, based largely on the development of the setae, indicates that the nominate subspecies is confined to the Antarctic Peninsula and its offshore islands (including the South Shetland Islands), whilst specimens from the South Orkney Islands are probably consubspecific with individuals on the South Sandwich Islands. In comparison with other studies of the Acari, the results strengthen the case for the recognition of a South Orkadian biogeographical zone.

Taxonomic studies of Achnanthes (Bacillariophyta) in freshwater maritime antarctic lakes

1994 ◽  
Vol 72 (12) ◽  
pp. 1735-1748 ◽  
Author(s):  
D. R. Oppenheim
Keyword(s):  
Trophic Status ◽  
Maritime Antarctic ◽  
Widespread Occurrence ◽  
Orkney Islands ◽  
Signy Island ◽  
South Orkney Islands ◽  
Algal Material ◽  
Taxonomic Studies ◽  
One New Species ◽  
Eleven Species

Eleven species of Achnanthes from Signy Island, South Orkney Islands are described including one new species. Benthic algal material from a range of shallow lakes of varying trophic status was examined by light microscopy and scanning electron microscopy. Detail of morphology is provided with an overview of the taxonomic literature for each species. In all cases source descriptions are cited, and where possible holotype and lectotype material was examined. The variation between populations inhabiting different lakes is considered. An examination of the geographical distribution of Achnanthes in southern latitudes from the literature confirms numerous records of widespread occurrence in freshwater environments in sub-antarctic regions but not from higher latitudes. Key words: Achnanthes, Antarctic, taxonomy, benthic, phytogeography.

Antarctic Ecosystems The freshwater lakes of Signy Island and their fauna

1967 ◽  
Vol 252 (777) ◽  
pp. 347-362 ◽  
Keyword(s):  
Summer Season ◽  
Falkland Islands ◽  
Freshwater Lakes ◽  
Orkney Islands ◽  
Signy Island ◽  
Antarctic Expedition ◽  
South Orkney Islands ◽  
The Antarctic ◽  
Taxonomic Evaluation ◽  
British Sector

Prior to 1962 work on freshwater within the British Sector of the Antarctic had been confined to the collection of specimens and their subsequent taxonomic evaluation. Collections were made by such expeditions as the Scottish National Antarctic Expedition 1902- 04, the various Discover y Investigations in this region 1925-37, the British Graham Land Expedition 1934-37 and the Falkland Islands Dependencies Survey 1945-62. During the 1961/1962 summer season an ecological investigation of the freshwater lakes of Signy Island, South Orkney Islands, was started. This paper is an interim report on that work.

Chemistry of streams of Signy Island, maritime Antarctic: sources of major ions

1997 ◽  
Vol 9 (1) ◽  
pp. 3-11 ◽  
Author(s):  
A.P. Caulkett ◽  
J.C. Ellis-Evans
Keyword(s):  
Major Ions ◽  
Maritime Antarctic ◽  
General Study ◽  
Orkney Islands ◽  
Signy Island ◽  
South Orkney Islands ◽  
Dissolved Ions

A general study of the streams of Signy Island, South Orkney Islands, was undertaken to identify the effects of catchment, distance from source, and time on concentrations of dissolved ions. In the majority of cases catchment did not affect the chemistry of streams, although marine-derived ions were affected by distance from the sea. Na+, K+, Mg2+, Ca2+, Cl− and NH4+were derived from the thawing of the winter snowpack. NO3− was derived from areas of permanent ice. SiO44−, Ca2+, Mg2+ and CO2−3 were derived from crustal weathering. Although PO43− was also derived from crustal weathering, it was released as a pulse related to the thawing of the soil.

scholarly journals Ocean currents as a potential dispersal pathway for Antarctica’s most persistent non-native terrestrial insect

Polar Biology ◽  
2021 ◽  
Author(s):  
Jesamine C. Bartlett ◽  
P. Convey ◽  
K. A. Hughes ◽  
S. E. Thorpe ◽  
S. A. L. Hayward
Keyword(s):  
Antarctic Peninsula ◽  
Native Species ◽  
Sea Water ◽  
Ocean Current ◽  
The South ◽  
Near Surface ◽  
Orkney Islands ◽  
Signy Island ◽  
South Orkney Islands ◽  
The Antarctic

AbstractThe non-native midge Eretmoptera murphyi is Antarctica’s most persistent non-native insect and is known to impact the terrestrial ecosystems. It inhabits by considerably increasing litter turnover and availability of soil nutrients. The midge was introduced to Signy Island, South Orkney Islands, from its native South Georgia, and routes of dispersal to date have been aided by human activities, with little known about non-human-assisted methods of dispersal. This study is the first to determine the potential for dispersal of a terrestrial invertebrate species in Antarctica by combining physiological sea water tolerance data with quantitative assessments of ocean current journey times. Fourth instar larvae tolerated sea water submergence for up to 21 days, but submerged egg sacs had significantly reduced hatching success. Using near-surface drifter data, we conclude that ocean current dispersal from Signy Island would not present a risk of species transfer beyond the South Orkney Islands on the tested timescales. However, if E. murphyi were to be introduced to the South Shetlands Islands or Adelaide Island, which are located offshore of the Antarctic Peninsula, there would be a risk of successful oceanic dispersal to neighbouring islands and the Antarctic Peninsula mainland. This study emphasises the need for effective biosecurity measures and demonstrates the role that currently undocumented pathways may have in dispersing non-native species.

Reproduction and larval growth of Harpagifer antarcticus Nybelin (Pisces, Notothenioidei)

1992 ◽  
Vol 4 (4) ◽  
pp. 421-430 ◽  
Author(s):  
M. G. White ◽  
P. J. Burren
Keyword(s):  
Larval Growth ◽  
Closely Related Species ◽  
Antarctic Species ◽  
Male And Female ◽  
Orkney Islands ◽  
Signy Island ◽  
South Orkney Islands ◽  
Scotia Arc ◽  
The Antarctic ◽  
Demersal Species

The spiny plunder-fish, Harpagifer antarcticus, is a common shallow-water demersal species distributed along the southern limb of the Scotia Arc. A year round study was made of its reproductive biology at Signy Island, South Orkney Islands, for comparison with populations from the Antarctic Peninsula and with H. georgianus at South Georgia. Adult H. antarcticus inhabit rubble substrata and spawn 300–1500 eggs into a nest during May/July. The nest is guarded by both male and female fish during an incubation period of up to 150 days. After hatching during November/December the larvae grow at a rate of 0.082 mm d−1 (summer), 0.049 mm d−1 (winter) and 0.067 mm d−1 (annual), calculated from a time-series of samples collected from the field. This rate of growth is slow even among Antarctic species but is similar to the closely related species H. georgianus. Adult male and female H. antarcticus at the South Orkney Islands attain a maximum standard length of 88 mm and 85 mm respectively.

scholarly journals Evidence of strong small‐scale population structure in the Antarctic freshwater copepod Boeckella poppei in lakes on Signy Island, South Orkney Islands

2020 ◽  
Vol 65 (9) ◽  
pp. 2024-2040 ◽  
Author(s):  
Claudia S. Maturana ◽  
Nicolás I. Segovia ◽  
Claudio A. González‐Wevar ◽  
Angie Díaz ◽  
Sebastián Rosenfeld ◽  
...  
Keyword(s):  
Population Structure ◽  
Small Scale ◽  
Orkney Islands ◽  
Signy Island ◽  
South Orkney Islands ◽  
Scale Population ◽  
The Antarctic
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