1988 Volume 49 Issue 3 Pages 149-156
Vertical profiles of dissolved manganese were measured in the anoxic hypolimnion of Lake Fukami-ike, from May to June 1987. The dissolved manganese in the hypolimnion water was specified by ultrafiltration and by XAD-2 resin. Percentages of dissolved manganese in four molecular weight fractions were 21 to 75% (M.W. <1, 000), 25 to 55% (M.W. 1, 000-50, 000). 2 to 7% (M.W. 50, 000-200, 000) and 3 to 30% (M.W. > 200, 000), respectively. The amounts of dissolved manganese adsorbed by XAD-2 resin at neutral pH were nearly equal to those measured by ultrafiltration in the latter three high molecular weight fractions. These results indicate that about 40% of total dissolved manganese was present as organic forms, mainly having a molecular weight of 1, 000 to 50, 000, in the hypolimnion of Lake Fukami ike.
