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Registros recuperados: 3
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20th century fluctuations in the abundance of siliceous microorganisms preserved in the sediments of the Puyuhuapi Channel (44° S), Chile RChHN
REBOLLEDO,LORENA; LANGE,CARINA B.; FIGUEROA,DANTE; PANTOJA,SILVIO; MUÑOZ,PRÁXEDES; CASTRO,RODRIGO.
We present a 100-year reconstruction of siliceous export production from sediments of the Puyuhuapi Channel (44° S, 70° W) in the Chilean fjords. We use accumulation rates and concentrations of diatoms and silicoflagellates, organic carbon (Corg) and biogenic opal (SiOPAL) as proxies of export production, and fluctuations in the contribution of freshwater diatoms as proxies of rainfall in the hinterland and river runoff. Box core sediments collected at two sites within the Puyuhuapi Channel were analyzed: Station 35 (at the head of the fjord; 56 m water depth) and Station 40 (in the middle of the Channel; 270 m water depth). Surface sedimentation rates were 0.75 cm yr-1 at Station 35 and 0.25 cm yr-1 at Station 40. SiOPAL content averaged ~ 4 % at both...
Tipo: Journal article Palavras-chave: Siliceous microorganisms; Diatoms; Sediments; Export production; Puyuhuapi Channel; Chilean fjords.
Ano: 2005 URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-078X2005000300009
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Archaeal and bacterial assemblages in the Oxygen Minimum Zone of the upwelling ecosystem off Central Chile as determined by organic biomarkers Gayana
SRAIN,BENJAMÍN; SEPÚLVEDA,JULIO; PANTOJA,SILVIO; SUMMONS,ROGER E; QUIÑONES,RENATO A; LEVIPAN,HÉCTOR A.
Organic biomarkers were used to investigate the influence of seasonal changes in oxygenation and water chemistry on the distribution of archaea and bacteria in the water column and surface sediments of the continental shelf off central Chile (ca. 36°S), an area influenced by seasonal upwelling and the development of an oxygen minimum zone. We were interested in establishing if occurrence of archaea and bacteria responds to oxygenation and water chemistry for which we analyzed archaeal isoprenoid (i) and bacterial branched (br) glycerol dialkyl glycerol tetraethers (GDGTs). Our results combined with molecular data from a year round observational program at the same sampling site and depths indicatives the occurrence and dominance of the marine pelagic group...
Tipo: Journal article
Ano: 2015 URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-65382015000100005
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Sedimentos laminados de la Bahía Mejillones como registro de cambios temporales en la productividad fitoplanctónica de los últimos ~ 200 años RChHN
CANIUPÁN,MAGALY; VILLASEÑOR,TANIA; PANTOJA,SILVIO; LANGE,CARINA B; VARGAS,GABRIEL; MUÑOZ,PRÁXEDES; SALAMANCA,MARCO.
Con el objetivo de reconstruir los cambios temporales de la productividad fitoplanctónica durante el pasado reciente, se han analizado los contenidos de carbono orgánico total, ópalo biogénico, "chlorins" y alquenonas en un testigo de sedimentos laminados recuperado de la Bahía Mejillones. Adicionalmente, los parámetros físicos medidos (contenido de agua, densidad seca, susceptibilidad magnética, rayos-X y escala de grises) contribuyeron a la caracterización de los sedimentos. El testigo recuperado con un sacatestigo de caja (Testigo 3; 23°03' S, 70°27' W; 80 m de profundidad de la columna de agua) registró una tasa de sedimentación de 0,18 cm año-1 (basada en mediciones de 210Pb). La extrapolación de esta tasa de sedimentación a la base del testigo da...
Tipo: Journal article Palavras-chave: Sedimentos laminados; Carbono orgánico; Chlorins; Alquenonas; Ópalo biogénico.
Ano: 2009 URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-078X2009000100006
Registros recuperados: 3
Primeira ... 1 ... Última
 

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