SEASONAL-VARIATIONS IN NA, K, MG AND CA AND CHARGE BALANCE IN MARINE BROWN-ALGAE FROM SAURASHTRA COAST (NW COAST OF INDIA)

Seasonal variation of Na, K, Mg and Ca were estimated in Cystoseira in dica, Sargassum tenerrimum and S. johnstonii. Abundance of these eleme nts were higher during the rapid growth stage but decreased subsequent ly. Monovalent cations (Na + K) strongly correlated with Cl content su ggesting that these cations were balanced by chloride ions. Divalent c ations (Ca + Mg) seem to be balanced by the anion sulphate. Ash conten t of the algae was accounted by these major cations and anions. Charge equivalent among these cations and anions was not balanced in the ash of the algae. The cations charge equivalence could be balanced by chl oride and sulphate in addition to the anions of C, N and P origin (OH- , RCOO(-) H2PO3- etc.). A significant correlation (P <0.001) between p er cent of negative ions deficit and per cent of excessive unbalanced cations was observed. Perhaps 9-32% (on large data base upto 60%) of t he organic matter participate in charge balance of cations. Intertidal position seemed to affect the osmoregulation process.