Coexisting Manganese Species in Surface Water of the Ukraine and Their Significance for Aquatic Ecosystems

The results of long-term research on the concentrations and coexisting manganese species in different-type water bodies of the Ukraine (rivers, reservoirs, estuaries, small lakes, and ponds) are summarized. High manganese concentrations are characteristic, as a rule, of the hypolimnion zone. The ratio of particulate and dissolved manganese species depends on the type of the water body and their transformation processes in this specific water body. The concentrations of dissolved manganese in reservoirs, lakes, and estuaries much increase in conditions of oxygen deficiency and anaerobic deep water. The weight fraction of labile forms is large, which is characteristic of manganese. In water bodies rich in humic substances a large fraction of dissolved manganese is incorporated in complex compounds. In small lake and pond systems, carbohydrates play an essential role in binding of Mn(II).