Accumation rates of manganese in manganese nodules using total alpha activity

The manganese content of 4 manganese nodules was determined by atomic absorption. The decrease of total alpha activity was used to evaluate Mn accumulation. Because CaCO3 is a Mn-free diluent, the Mn concentration results and the nodules accumulation rate results are given on a carbonate-free basis. Nodule densities were assumed to be 2.5 g/cm³. The Mn accumulation rates are calculated per unit cross sectional area of the nodule rather than per unit surface area.