EFFECT OF SALINITY ON THE GROWTH AND FATTY-ACID COMPOSITION OF ULVA-PERTUSA KJELLMAN (CHLOROPHYTA)

Changes in the specific growth rate and fatty acid composition of Ulva pertusa were observed at various salinities (20, 25, 30, 35 and 40 pa rts per thousand), in a completely randomized laboratory experiment. S pecific growth rates were highest at 30 and 35 parts per thousand. Moi sture content did not significantly vary between salinity treatments. Crude lipid contents of thalli at salinities above 30 parts per thousa nd were 30 - 70% higher than at lower salinities (e. g., at 30 parts p er thousand, crude lipid was 1.47% of fresh weight or 5.59% of dry wei ght; at 25 parts per thousand, crude lipid was 0.42% of fresh weight, or 1.93% of dry weight). High salinity increased the overall levels of the n-3 major polyunsaturated fatty acids (16 : 4n-3, 18 : 3n-3 and 1 8 : 4n-3), whereas, low salinity increased the levels of the fatty aci ds, 16 : 0, 18 : 1, 20 : 3 and the essential fatty acid 20 : 5.