B. Butow et al., THE SYNERGISTIC EFFECT OF CARBON CONCENTRATION AND HIGH-TEMPERATURE ON LIPID-PEROXIDATION IN PERIDINIUM GATUNENSE, Journal of plankton research, 20(2), 1998, pp. 355-369
Lipid peroxidation in Peridinium samples taken from two different dept
hs in Lake Kinneret fluctuated throughout the spring with an overall i
ncreasing trend. Samples from 0.5 and 5 m showed a similar peroxidatio
n pattern, which was maximal after the fall off in algal biomass. The
rapid decline in Peridinium biomass coincided with ambient lake temper
atures of 21-23 degrees C. Fatty acid composition profiles were simila
r at both depths, although after the peak of the bloom, a significant
increase in polyunsaturated fatty acids and oleic acid was only found
at 0.5 m, together with a decrease in the percentage of polyunsaturate
d fatty acids. These effects were related to ambient light stress rath
er than a result of lipid peroxidation. Lake samples taken at differen
t periods of the bloom and incubated at various temperatures showed di
fferential peroxidation. Higher temperatures caused increased lipid pe
roxidation, but this appeared to be dependent on the sampling period.
Samples withdrawn from the lake at the beginning of the bloom showed l
ittle peroxidation after a 5 day incubation at 14 degrees C, room temp
erature (25 degrees C) or ambient lake temperature (16 degrees C) comp
ared to mid-bloom samples in which there was a significant increase in
peroxidation when they were incubated at room temperature (25 degrees
C) or ambient lake temperature (22 degrees C). Incubation at 14 degre
es C inhibited peroxidation; however, samples from mid-bloom again sho
wed enhanced peroxidation compared with those from the beginning of th
e bloom. These in situ results suggested a relationship between temper
ature, another environmental variable during the bloom and lipid perox
idation in Peridinium. As total dissolved inorganic carbon (DIG) conce
ntrations fall significantly during the progress of the bloom and repr
esent an important source of environmental stress, laboratory experime
nts were established to investigate the synergistic effect of temperat
ure and carbon nutrition on lipid peroxidation in Peridinium cultures.
Increased temperature alone caused a slight increase in lipid peroxid
ation, but this was greatly augmented by carbon limitation. Although c
arbon limitation induced increased catalase activity, at higher temper
atures activity declined after 48 h, allowing for the substantial incr
ease in lipid peroxidation.