Eat. Floreto et S. Teshima, THE FATTY-ACID COMPOSITION OF SEAWEEDS EXPOSED TO DIFFERENT LEVELS OFLIGHT-INTENSITY AND SALINITY, Botanica marina, 41(5), 1998, pp. 467-481
Three seaweeds Ulva pertusa (Chlorophyta), Grateloupia sparsa (Rhodoph
yta) and Sargassum piluliferum (Phaeophyta) were exposed to combinatio
ns of 2 light intensities (15 and 60 mu E m(-2) s(-1)) and 3 salinitie
s (10, 35 and 50 parts per thousand) in a 2 x 3 factorial experiment t
o examine the effects on their fatty acid (FA) profiles. In Ulva, expo
sure to the high light intensity and low salinity combination resulted
in huge decreases in the quantitative (mgg(-1) dry weight) total FA c
ontent. High light intensity increased the quantitative levels of most
saturated FAs (14:0, 15:0, 16:0 and iso-17:0). In Grateloupia, low an
d high salinity exposure resulted in significant increases in the tota
l FA content, total polyunsaturated FAs, total saturates and total mon
oenes compared to normal salinity (35 parts per thousand) exposure. Hi
gh light intensity increased the quantitative levels of 14:0, 18:1 n-9
, 18:1 n-7, 20:5 n-3 and total n-3. In Sargassum, high light intensity
resulted in a decrease in the quantitative levels of almost all FAs.
A trend of increasing levels of 18:4 n-3, 20:4 n-6, 20:5 n-3, total n-
3 and total n-6 FAs were observed with increasing salinity. Exposure t
o high salinity in Ulva and Sargassum, and low and high salinities in
Grateloupia resulted in significantly higher levels of total FAs compa
red to unexposed fresh seaweeds. Changes in the quantitative FA conten
t of Ulva were a consequence of light and/or salinity-controlled growt
h rates.