1. In the culture of Porphyra in the sea water supplemented with metals, the uptakes of Mn and Cd were relatively high and increased in proportion to culture time when the metal concentration in water was high.
2. Fe distributed evenly in all the three parts of fronds. Mn was concentrated in surface and middle layer, while Cd was accumulated mainly in the middle layer and a little in the surface layer. In general the uptake was high in the middle layer.
3. In the uptake of Mn there was a clear distinction between light and dark conditions, that is, Mn was absorbed only during light period. While, Cd was absorbed regardless of light and dark periods.