Foraminíferos bentónicos de canales australes: canal Kirke, Golfo Almirante Montt y Seno Úlitma Esperanza, XII Región, Magallanes y Antártica chilena
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1995
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Para el presente trabajo se analizaron seis muestras de sedimentos marinos colectadas en canal Kirke, golfo Almirante Montt y seno Ultima Esperanza (51°S) en la XIIa Región chilena. El material fue extraído durante el crucero CIMAR-FIORDO II organizado por el Comité Oceanógrafico Nacional (CONA) a bordo del buque de la Armada chilena AGOR VIDAL GORMAZ, siendo su objetivo el estudio de los foraminíferos. Se describe e ilustra 51 especies de foraminíferos bentónicos, pertenecientes a 19 familias y 31 géneros y se informa sobre su abundancia relativa. Sólo una estación (N°56) brindó abundante microfauna dominando la muestra: Globocassidulina crassa (43,8%), G. subglobosa (4,6%), Angulogerina angulosa (35,0%), Buccella peruviana (6,7%) y Pullenia subcarinata (3,2%). La escasa microfauna encontrada al interior del seno Ultima Esperanza se atribuye a la presencia de una barrera natural conformada por la diferencia de profundidad entre este seno y el canal Kirke, a un posible ambiente hiposalino y a la intervención humana en el sector la que estaría generando un
proceso de eutroficación del seno. La gran similitud de la microfauna encontrada con los foraminíferos descritos para el Pacífico sudoriental, sugiere un aporte constante de masas de agua de características subantárticas desde el océano hasta la entrada occidental del Canal Kirke, las que penetrarían con dificultad al seno Ultima Esperanza.
The benthonic foraminifers collected in six samples of marine sediments from Kirke chanel, Almirante Montt gulf and seno Ultima Esperanza, (51°S), XIIa Region, Magallanes y Antartica Chilena, were studied. This material was obtained during the "CIMAR-FIORDO II" expedition organized by National Oceanographic Commitee (CONA), dredged by AGOR VIDAL GORMAZ, Chilean Navy. Fifty one species were found (19 families and 31 genera). Only one sample (N° 56) was plenty of foraminifers, the dominant species were: Globocassidulina crassa (43,8%), G. subglobosa (4,6%), Angulogerina angulosa (35,0%), Buccella peruviana (6,7%) y Pullenia subcarinata (3,2%). This association was only found at Kirke Channel entrance suggesting a natural barrier between Kirke and Ultima Esperanza, probably salinity and depth was the principal environmental factor to the fauna distribution. Another factor posible could be the human presence in the area. The fauna was tipically subantartic and common in the Southeastern Pacific, then a mass water comming fron this area, arrive to the Kirke Channel entrance, but they can not go on to the Seno Ultima Esperanza.
The benthonic foraminifers collected in six samples of marine sediments from Kirke chanel, Almirante Montt gulf and seno Ultima Esperanza, (51°S), XIIa Region, Magallanes y Antartica Chilena, were studied. This material was obtained during the "CIMAR-FIORDO II" expedition organized by National Oceanographic Commitee (CONA), dredged by AGOR VIDAL GORMAZ, Chilean Navy. Fifty one species were found (19 families and 31 genera). Only one sample (N° 56) was plenty of foraminifers, the dominant species were: Globocassidulina crassa (43,8%), G. subglobosa (4,6%), Angulogerina angulosa (35,0%), Buccella peruviana (6,7%) y Pullenia subcarinata (3,2%). This association was only found at Kirke Channel entrance suggesting a natural barrier between Kirke and Ultima Esperanza, probably salinity and depth was the principal environmental factor to the fauna distribution. Another factor posible could be the human presence in the area. The fauna was tipically subantartic and common in the Southeastern Pacific, then a mass water comming fron this area, arrive to the Kirke Channel entrance, but they can not go on to the Seno Ultima Esperanza.
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Foraminíferos bentónicos, Canal Kirke, Golfo Almirante Montt, Seno Última Esperanza
Citación
Anales del Instituto de la Patagonia, Vol. 27, pp. 91-104, 1995