l. Trace metals in Porphyra were recovered for more than 95% by the treatment of the alga with HNO3 -HClO4 -HCl.
2. Ten to 20% of the standard deviations were obtained by the analyses of the alga.
3. The trace metals in Porphyra could be divided into two groups according to their tendencies of seasonal and regional variations, one is the group of Fe, Zn, Mn, and Cu and the other group is Pb and Cd.
4. The variation of chlorophyll a content was quite similar to that of Fe.
5. The content of metals was different in Porphyra collected from regions other than the fixed stations.