Cienc. Tecnol. Mar, 29 (1): 15-23, 2006
DISTRIBUCIÓN DE HIERRO Y MANGANESO REDUCIDO EN AGUAS INTERSTICIALES ENTRE
BOCA DEL GUAFO (44o S) Y GOLFO ELEFANTES (46,5o S), CHILE AUSTRAL*
DISTRIBUTION OF REDUCED IRON AND MANGANESE IN POREWATERS BETWEEN BOCA DEL GUAFO (44o S) AND GOLFO ELEFANTES (46,5o S) IN SOUTHERN CHILE*
LUIS PINTO 1 CECILIA RIVERA 2
1 Departamento de Oceanografía, Universidad de Concepción. Casilla 160 C, Concepción. E-mail: luispinto@udec.cl 2 Programa de Oceanografía Física y Clima, Universidad de Concepción, Concepción.
Recepción: 21 de noviembre de 2004 - Versión corregida aceptada: 21 de marzo de 2006.
ABSTRACT
Organic matter degradation in coastal sediments is an important process during early diagenesis affecting directly the redox condition of the sedimentary strata. Availability of different terminal electron acceptors, such as iron and manganese oxides, could play an important role during the remineralization of organic carbon. The first measurements of reduced iron and manganese in pore waters between boca del Guafo and golfo Elefantes in southern Chile were carried out during the CIMAR 4 Fiordos oceanographic cruise. Atomic absorption spectrometry was used to determine the concentrations of Fe(II) and Mn(II). Concentrations of up to 3 mM of Fe(II) were found in surface sediments near the head of the most populated fjord of the region.
These results allow us to establish a trend with increasing concentrations in porewater from the most oceanically influenced station toward the head of fjords with an important presence of freshwater. This observation is more notorious at the head of Aysén fjord, which is influenced by estuarine and anthropogenic conditions, more than the other studied fjords.
Key words: Reduced iron, reduced manganese, pore water, fjord, recent sediments, Chile.