Phosphorus, iron, and manganese distribution in sediment cores of six Wisconsin lakes

Depositional patterns of iron, manganese, and phosphorus in one central and five northern Wisconsin lakes ranging from oligotrophic to eutrophic, primarily from natural causes, have been investigated. One-meter cores from one or more locations within each lake were analyzed. The historical pattern of iron and manganese deposition is closely related to the pattern of phosphorus deposition in most of the cores. Four of the nine cores show a strong positive correlation coefficient between P and Fe and seven between P and Mn. Manganese has more predictive value than iron for determining the concentration of phosphorus in a given core; however, the iron content appears to be the dominant factor in the phosphorus sorptive and retentive capacity of sediments.