The early diagenesis of iron in pelagic sediments: a multidisciplinary approach

Abstract

Biogeochemical reactions of iron within pelagic sediments from the eastern and western equatorial Atlantic are investigated by means of pore water chemistry, chemical leaching experiments and total elemental determinatins, color reflectance spectroscopy, rock magnetic measurements and TEM observations of the magnetic fraction. Results indicate that in the presence of nitrate, ascorbate (a weak reducing agent) leachable iron decreased with depth from the sediment surface. Within this upper sediment region, iron assimilation by bacteria is indicated as magnetosomes were found by TEM observations throughout the whole core. Extractions with a strong reducing agent (dithionite), representing iron..