The carbohydrate, lipid, and protein composition of coral tissue
and zooxanthellae were compared in Hawaiian Pocillopora damicornis (Linnaeus)
colonies kept at different ammonium levels. Corals were maintained at
two levels of ammonium enrichment (20 uM and 50 uM), in locally drawn
seawater with < 1 uM ammonium, and in water stripped of ammonium by
running over a flume with macroalgae. No significant differences due to the
treatment were found in the biochemical composition of the coral tissue. The
values from control corals were 900, 275, and 170 ug/cm2 for protein, carbohydrates,
and lipids, respectively. Under all treatments the carbohydrate levels of
zooxanthellae were inconsistent, but did not differ much from the control value
of about 650 pg per cell. Lipid content in the control of nonenriched algae
remained at ca. 140 pg per cell. However, in the 20-uM treatment algal lipid
content increased to about 200 pg per cell during the second and fourth weeks,
decreased slightly at 6 weeks, and remained at 164 pg per cell after 8 weeks. In
the 50-uM ammonium treatment, there was a decrease to levels of about 40 pg
lipids per cell for the entire period. Protein content increased from a control
value of 590 pg per cell to ca. 950 pg per cell after 2 and 4 weeks of 20-uM
ammonium enrichment and then after 6 weeks dropped back to the control
level. At 50-uM ammonium the algal protein content increased after 2 weeks
and remained at about 900 pg per cell after 6 and 8 weeks. The preliminary
nature of this study is emphasized
