SULFATE-MEDIATED IRON LIMITATION AND EUTROPHICATION IN AQUATIC ECOSYSTEMS

In large parts of the peaty lowlands of The Netherlands, alkaline, sul phate-enriched river water poor in iron is let in to compensate for de creased ground water levels. As a result, iron input rates decrease wh ile sulphate reduction rates in the anaerobic sediment increase. Iron sulphide precipitation and decreased iron input result in iron exhaust ion, sulphide accumulation and increased phosphate mobilization in the anaerobic sediments. Futhermore, iron shortage and sulphide toxicity can occur in aquatic species while disturbance of the iron cycle resul ts in increased phosphate levels in the water layer.