Orogenic Growth of the Fuegian Andes (52–56°) and Their Relation to Tectonics of the Scotia Arc

2015 ◽  
pp. 241-267 ◽  
Author(s):  
Matías C. Ghiglione
Keyword(s):  
Scotia Arc

Corrigendum to ‘The global relevance of the Scotia Arc: An introduction’

2015 ◽  
Vol 133 ◽  
pp. 378
Author(s):  
Andrés Maldonado ◽  
Ian W.D. Dalziel ◽  
Philip T. Leat
Keyword(s):  
Scotia Arc

scholarly journals Biodiversity of echinoids and their epibionts around the Scotia Arc, Antarctica

2008 ◽  
Vol 20 (3) ◽  
pp. 227-244 ◽  
Author(s):  
Katrin Linse ◽  
Lisa J. Walker ◽  
David K.A. Barnes
Keyword(s):  
Southern Ocean ◽  
Current Knowledge ◽  
Sea Urchins ◽  
Marine Biodiversity ◽  
Current View ◽  
Depth Range ◽  
Tissue Mass ◽  
Scotia Arc ◽  
Biodiversity Changes ◽  
Study Species

AbstractThe Scotia Arc, linking the Magellan region with the Antarctic Peninsula, comprises young and old islands both near continents and isolated, and is the only semi-continuous link between cool temperate and Antarctic environments. It is an ideal region for studies on how marine biodiversity changes across an extended transition zone. Echinoids (sea urchins) and their associated epibionts were found across depths from 91–1045 m, with 19 species from shelf and four from slope depths. The 23 species from 38 trawls represent 31% of all echinoid species known from the Southern Ocean and 38% of the shelf/upper slope echinoids. The specimens collected comprise representatives of the five families Cidaridae, Echinidae, Temnopleuridae, Schizasteridae and Pourtalesiidae. Echinoids are probably a good model for how well we know Antarctic shelf and slope megabenthos; none of the species we report are new to science but we found nine (39%) of our study species present at new localities, some thousands of kilometres from previous findings. New biogeographic ranges are illustrated forCtenocidaris gigantea,C. nutrix,C. spinosa,Abatus curvidens,A. ingens,A. shackletoni,Amphineustes rostratus,Tripylaster philippiandPourtalesia aurorae. Southern Ocean echinoids show eurybathy as the mean depth range of our study species was 1241 m and only one was at less than 500 m. The current view of echinoid dominance of super-abundance in the shallows seems to be not transferable to shelf and slope depths as only one of 38 trawls was dominated by echinoids. Current knowledge on maximum sizes in Antarctic echinoids seems to be good as our morphometric measurements were mainly within known size ranges. Regular echinoids increased predictably in mass with increasing test length, apart fromCtenocidaris spinosa. Tissue mass of cidaroid species was ~17%, but across irregular species varied from 17.7–8.9%. No epibionts were found on irregular echinoids or Echinidae but 70 cidaroids examined carried 51 species representing ten classes. Many of these species are reported as cidaroid epibionts for the first time. Cidaroids and their epibionts constituted > 38% of the total macrofaunal richness in the trawls they were present in. Echinoids and their epibionts clearly contribute significantly to Southern Ocean biodiversity but are minor components of biomass except in the shallows.

Polychaete diversity in the Scotia Arc benthic realm: Are polychaetes tracers for faunal exchange?

Polar Biology ◽  
2015 ◽  
Vol 39 (7) ◽  
pp. 1233-1244
Author(s):  
Américo Montiel ◽  
Eduardo Quiroga ◽  
Dieter Gerdes ◽  
Brigitte Ebbe
Keyword(s):  
Scotia Arc

Aspects of the Geology of the Scotia Arc

1959 ◽  
Vol 96 (6) ◽  
pp. 425-441 ◽  
Author(s):  
D. H. Matthews
Keyword(s):  
Crustal Structure ◽  
Scotia Sea ◽  
Scotia Arc ◽  
The Caribbean ◽  
Sea Area

AbstractA review is given of the geology of the islands of the Scotia Arc. The provenance of the sedimentary materials is considered and it is concluded that the islands probably represent areas with a crustal structure of a continental type. The crustal structure of the Scotia Sea area is briefly compared with that of the Caribbean.

The role of fish in the Antarctic marine food web: differences between inshore and offshore waters in the southern Scotia Arc and west Antarctic Peninsula

2002 ◽  
Vol 14 (4) ◽  
pp. 293-309 ◽  
Author(s):  
ESTEBAN BARRERA-ORO
Keyword(s):  
Food Web ◽  
Antarctic Peninsula ◽  
Demersal Fish ◽  
Pelagic Fish ◽  
West Antarctic ◽  
Antarctic Marine ◽  
Scotia Arc ◽  
West Antarctic Peninsula ◽  
The Antarctic

The role of fish in the Antarctic food web in inshore and offshore waters is analysed, taking as an example the coastal marine communities of the southern Scotia Arc (South Orkney Islands and South Shetland Islands) and the west Antarctic Peninsula. Inshore, the ecological role of demersal fish is more important than that of krill. There, demersal fish are major consumers of benthos and also feed on zooplankton (mainly krill in summer). They are links between lower and upper levels of the food web and are common prey of other fish, birds and seals. Offshore, demersal fish depend less on benthos and feed more on zooplankton (mainly krill) and nekton, and are less accessible as prey of birds and seals. There, pelagic fish (especially lantern fish) are more abundant than inshore and play an important role in the energy flow from macrozooplankton to higher trophic levels (seabirds and seals). Through the higher fish predators, energy is transferred to land in the form of fish remains, pellets (birds), regurgitation and faeces (birds and seals). However, in the general context of the Antarctic marine ecosystem, krill (Euphausia superba) plays the central role in the food web because it is the main food source in terms of biomass for most of the high level predators from demersal fish up to whales. This has no obvious equivalent in other marine ecosystems. In Antarctic offshore coastal and oceanic waters the greatest proportion of energy from the ecosystem is transferred to land directly through krill consumers, such as flying birds, penguins, and seals. Beside krill, the populations of fish in the Antarctic Ocean are the second most important element for higher predators, in particular the energy-rich pelagic Myctophidae in open waters and the pelagic Antarctic silver fish (Pleuragramma antarcticum) in the high Antarctic zone. Although the occurrence of these pelagic fish inshore has been poorly documented, their abundance in neritic waters could be higher than previously believed.

scholarly journals Population structure and phylogeography of the Gentoo Penguin (Pygoscelis papua) across the Scotia Arc

2016 ◽  
Vol 6 (6) ◽  
pp. 1834-1853 ◽  
Author(s):  
Hila Levy ◽  
Gemma V. Clucas ◽  
Alex D. Rogers ◽  
Adam D. Leaché ◽  
Kate L. Ciborowski ◽  
...  
Keyword(s):  
Population Structure ◽  
Gentoo Penguin ◽  
Pygoscelis Papua ◽  
Scotia Arc

scholarly journals A newly discovered radiation of endoparasitic gastropods and their coevolution with asteroid hosts in Antarctica

2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Kara K. S. Layton ◽  
Greg W. Rouse ◽  
Nerida G. Wilson
Keyword(s):  
Marine Invertebrates ◽  
Global Scale ◽  
Morphological Data ◽  
Sea Stars ◽  
Single Host ◽  
Scotia Arc ◽  
Event Based ◽  
Genus One ◽  
Future Work ◽  
The Antarctic

Abstract Background Marine invertebrates are abundant and diverse on the continental shelf in Antarctica, but little is known about their parasitic counterparts. Endoparasites are especially understudied because they often possess highly modified body plans that pose problems for their identification. Asterophila, a genus of endoparasitic gastropod in the family Eulimidae, forms cysts in the arms and central discs of asteroid sea stars. There are currently four known species in this genus, one of which has been described from the Antarctic Peninsula (A. perknasteri). This study employs molecular and morphological data to investigate the diversity of Asterophila in Antarctica and explore cophylogenetic patterns between host and parasite. Results A maximum-likelihood phylogeny of Asterophila and subsequent species-delimitation analysis uncovered nine well-supported putative species, eight of which are new to science. Most Asterophila species were found on a single host species, but four species were found on multiple hosts from one or two closely related genera, showing phylogenetic conservatism of host use. Both distance-based and event-based cophylogenetic analyses uncovered a strong signal of coevolution in this system, but most associations were explained by non-cospeciation events. Discussion The prevalence of duplication and host-switching events in Asterophila and its asteroid hosts suggests that synchronous evolution may be rare even in obligate endoparasitic systems. The apparent restricted distribution of Asterophila from around the Scotia Arc may be an artefact of concentrated sampling in the area and a low obvious prevalence of infection. Given the richness of parasites on a global scale, their role in promoting host diversification, and the threat of their loss through coextinction, future work should continue to investigate parasite diversity and coevolution in vulnerable ecosystems.

scholarly journals Conservation implications of spatial genetic structure in two species of oribatid mites from the Antarctic Peninsula and the Scotia Arc

2018 ◽  
Vol 30 (2) ◽  
pp. 105-114 ◽  
Author(s):  
Bettine Jansen van Vuuren ◽  
Jennifer E. Lee ◽  
Peter Convey ◽  
Steven L. Chown
Keyword(s):  
Genetic Structure ◽  
Antarctic Peninsula ◽  
Sequence Data ◽  
Spatial Genetic Structure ◽  
Complex Structure ◽  
Regional Scale ◽  
Terrestrial Invertebrates ◽  
Conservation Implications ◽  
Scotia Arc ◽  
The Antarctic

AbstractMitochondrial and nuclear sequence data from two Antarctic ameronothroid mites, Halozetes belgicae and Alaskozetes antarcticus, were used to address three key questions important for understanding both the evolution of biodiversity and its future conservation in the Antarctic Peninsula Region: i) Do populations of mites across the Antarctic Peninsula and Scotia Arc constitute distinct genetic lineages? ii) What implications does the spatial genetic structure in these species have for current understanding of the region’s glacial history? iii) What are the conservation implications of these findings? Our results indicate that both mite species have been present in the Antarctic since at least the Pliocene. At the regional scale, both species are comprised of a number of divergent, but sympatric, lineages that are genetically as distinct as some species within the genera Halozetes and Alaskozetes. At the local scale, complex structure suggests limited and stochastic post-Holocene dispersal. For both species, considerable spatial genetic structure exists across the region, similar to that found in other terrestrial invertebrates. These results support the implementation of stringent biosecurity measures for moving between the Scotia Arc islands and the Antarctic Peninsula, and throughout the latter, to conserve both evolutionary history and future evolutionary trajectories.

scholarly journals Mesozoic tectonic evolution of the South Orkney Microcontinent, Scotia arc, Antarctica

1997 ◽  
Vol 134 (3) ◽  
pp. 383-401 ◽  
Author(s):  
R. A. J. TROUW ◽  
C. W. PASSCHIER ◽  
L. S. A. SIMÕES ◽  
R. R. ANDREIS ◽  
C. M. VALERIANO
Keyword(s):  
Upper Jurassic ◽  
Accretionary Wedge ◽  
The South ◽  
Orkney Islands ◽  
The Pacific ◽  
Exposed Part ◽  
Pacific Margin ◽  
Scotia Arc ◽  
Extensional Faulting ◽  
Five Phases

The South Orkney Islands are the exposed part of a continental fragment on the southern limb of the Scotia arc. The islands are to a large extent composed of metapelites and metagreywackes of probable Triassic sedimentary age. Deformation related to an accretionary wedge setting, with associated metamorphism from anchizone to the greenschist facies, are of Jurassic age (176–200 Ma). On Powell Island, in the centre of the archipelago, five phases of deformation are recognized. The first three, associated with the main metamorphism, are tentatively correlated with early Jurassic subduction along the Pacific margin of Gondwana. D4 is a phase of middle to late Jurassic crustal extension associated with uplift. This extension phase may be related to opening of the Rocas Verdes basin in southern Chile, associated with the breakup of Gondwanaland. Upper Jurassic conglomerates cover the metamorphic rocks unconformably. D5 is a phase of brittle extensional faulting probably associated with Cenozoic opening of the Powell basin west of the archipelago, and with development of the Scotia arc.

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