Iron reactivity in anoxic sediments in the Ría de Vigo (NW Spain)

摘要: Abstract The high sedimentation rates and organic matter contents in the sediments of Ria de Vigo (NW Spain) promote development anoxic conditions, determining dynamics elements like Fe conditioning his speciation reactivity. Four gravity cores were retrieved November 2012. In order to understand behavior these complex environments different fractions reactive iron analyzed. decrease highly sulfide with depth showed relationship between sulfur cycle middle outer zones ria. inner zone, apparition shallow methane gas may cause slower contents. without methane, sediment layers enriched iron −with a reactivity higher than other samples− observed. An increase was observed dithionite total from zone ria, according depth. Furthermore, (III)-bearing minerals zones, but not innermost area where is shallow. contents, mainly indicate that most (II) FeS. Moreover, pH values (6.86–7.98) could contribute formation stable pyrite along Vigo.