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 parts per thousand), in a completely randomized laboratory experiment. Specific growth rates were highest at 30 and 35 parts per thousand. Moisture content did not significantly vary between salinity treatments. Crude lipid contents of thalli at salinities above 30 parts per thousand were 30 - 70% higher than at lower salinities (e. g., at 30 parts per thousand, crude lipid was 1.47% of fresh weight or 5.59% of dry weight; 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 18 : 4n-3), whereas, low salinity increased the levels of the fatty acids, 16 : 0, 18 : 1, 20 : 3 and the essential fatty acid 20 : 5.