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Colección de artículos en temáticas antárticas publicados por investigadores de la Universidad de Magallanes en diferentes fuentes, acorde a las políticas del editor.
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Browsing Artículos by Subject "Biogeografía"
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Item Flora marina bentónica de la región austral de sudamérica y la antártica(Universidad de Magallanes, 2010) Ramírez, María ElianaEl conocimiento taxonómico de la flora marina bentónica de la región austral de Sudamérica, incluida la Antártica, está basado fundamentalmente en los registros de las expediciones europeas que recorrieron los mares australes durante los siglos XVIII, XIX y principios del siglo XX. Debido a la lejanía de estos territorios y a las dificultades logísticas para la realización de nuevas recolecciones en el área, poco se ha avanzado en la revisión crítica de los taxa publicados en la literatura hasta la fecha. El presente trabajo da a conocer un listado actualizado de esta flora marina, en base a las publicaciones y exploraciones recientes en el área. Adicionalmente y en base a este listado, se presenta un análisis biogeográfico con el objeto de establecer las relaciones entre la flora marina de la región austral de Sudamérica y aquélla de la región antártica.Item On the biogeography and ecology of the Southern Ocean decapod fauna(Institut de Ciències del Mar, CSIC, 1999) Gorny, MatthiasThe biogeography and ecology of decapod crustaceans was described for the higher latitudes of the Southern Ocean. The analyzed area included the transitional or antiboreal region of the South American continental shelves (south of about 42°30’S), the Antarctic continental shelves, the Subantarctic islands of the Scotia and the Kerguelen Arcs, the deep sea south of about 42°S and the pelagic realm between the Subtropical Convergence and the Antarctic continent. A broad base of own data and a review of the literature revealed the presence of 98 benthic decapod species in the entire area, with 92 species on the continental shelves and around the Subantarctic islands, and 6 species in the deep sea. A total of 34 decapod species live in the pelagic system south of the Subtropical Convergence. About 50 % of the benthic species, nearly all deep-sea species, but only one pelagic decapod are endemic in the analyzed sectors of the Southern Ocean. Eualus kinzeri (Caridea: Hippolytidae) is the only endemic decapod of the Antarctic continental shelves. By means of a multivariate cluster analysis the antiboreal decapod fauna of South America was separated from the species living around Antarctica and the Subantarctic islands of the Scotia and Kerguelen Arc. In contrast to earlier studies the northern distribution limit of the Antarctic decapod fauna was set at approximately 55°30’S, and includes species which are distributed on the southern tip of South America. The species number in the antiboreal region of South America is 79, and higher than known before. The caridean shrimps are the most numerous group within the entire area, and together with the anomuran crabs, the palinuran and astacuran lobsters they demonstrate a high degree of eurybathy compared to the Brachyura. The restriction of the Brachyura to shallow-water zones is discussed as one reason, that caused the absence of this group on the Antarctic continental shelves after the successive elimination of the shallow-water fauna during glaciation of the southern hemisphere.Item Patrones de diversidad y estructura genética en especies antárticas y subantárticas de Nacella (Nacellidae)(Universidad de Magallanes, 2016) González-Wevar, Claudio A.; Hüne, Mathias; Rosenfeld, Sebastián; Gérard, Karin; Mansilla, Andrés; Poulin, ElieLa biogeografía del Océano Austral es el resultado de la compleja interacción de distintas fuerzas macroevolutivas sobre su particular biota en el tiempo y en el espacio. Los procesos de tectónica de placas que derivaron en la separación de los continentes junto al establecimiento de la Corriente Circumpolar Antártica y el enfriamiento paulatino de la región desde el Eoceno se han asociado directamente a la composición, abundancia y distribución de su fauna marina bentónica. Más recientemente, los procesos glaciales del Cuaternario impactaron fuertemente la distribución de la variación genética intraespecífica en una variedad de taxones. El género Nacella (Patellogastropoda: Nacellidae) incluye 11 especies nominales que se distribuyen en distintas provincias del Océano Austral. En este estudio se compararon los patrones de diversidad y estructura genética a nivel del DNA mitocondrial de cuatro especies de Nacella provenientes de Antártica marítima (Nacella concinna), Sudamérica (Nacella magellanica) y de dos islas ubicadas en el sector Índico del Océano Austral: Kerguelén (Nacella edgari) y Marión (Nacella delesserti). Bajos niveles de diversidad genética y ausencia de estructura caracterizan a cada una de las especies analizadas lo que muestra el tremendo impacto del avance y retroceso de los hielos sobre la demografía de todas ellas. Baja diversidad haplotípica, genealogías cortas y las demografías específicas sugieren la ocurrencia de efectos poblacionales más severos en Antártica marítima e Isla Marión que en el resto de las regiones subantárticas.Item Polychaetes from Aysén Fjord, Chile: distribution, abundance and biogeographical comparison with the shallow soft-bottom polychaete fauna from Antarctica and the Magellan Province(Institut de Ciències del Mar, CSIC, 1999) Cañete, Juan I.; Leighton, G.L.; Aguilera, F.F.This paper analyzes the composition, abundance and biogeographical relationship of the benthic polychaetes collected in three shallow subtidal locations (mouth of Cuervo and Condor rivers and Acantilada Bay) from Aysen Fjord, AF, Chile (45ºS, 73ºW), and provides a comparison with data on shallow soft-bottom polychaetes from Antarctica and other locations of the Magellan Province: Dalcahue Channel, DC (42º22’S, 73º39’W), Puerto Cisnes, Puyuhuapi Channel, PC (44º43’S, 72º42’W) and Magellan Straits, MS. AF polychaete fauna comprises 38 species, the macrobenthic taxon being most representative in terms of abundance and species richness. The importance of polychaetes seems to be higher in fjords than in channels. Low numbers of common species were detected among DC, PC, MS and AF, indicating differences along the influence area of the Cape Horn Current or along the Magellan Province. The polychaetes from AF show low affinities with Antarctica; maximum number of common species was observed with the Antarctic Peninsula, whereas the lowest values were recorded from locations in the Ross and Weddell Seas. Coincidence in some ecological attributes between AF and Antarctica indicate that polychaetes may play an important and similar ecological role in both environments.Item The macrobenthic ecology of the straits of magellan and the beagle channel(Universidad de Magallanes, 2009) Thatje, Sven; Brown, AlistairThe macrobenthic community of the Straits of Magellan and the Beagle Channel was investigated using a Reineck box corer at 22 stations during the Chilean “Cimar Fiordo 3” expedition in 1997. A total of 173 taxa represented by 2188 individuals were identified and are reported for the investigated area. Clear exponential relationships with depth were revealed by analysis of abundance, biomass, species richness, and evenness. These patterns coincide with posited theories of pelagic-benthic coupling and the source-sink hypothesis of colonisation-extinction dynamics. Polychaeta dominated macrobenthic community abundance and biomass, 67% and 38% respectively, therefore consideration of biogeographic affinities concentrated on this taxon. 13 species of polychaetes observed in the study area co-occur in Antarctica suggesting biogeographic or evolutionary affinities between these adjacent regions.