Pigmentation encroached from the periphery of the
bleached area in flow treated samples. Chlorophyll a increased in flow-treated colonies throughout the
study and changed little in still treatments. Chlorophyll
c2, however, increased slightly in flow treatments
in the last 2 wk of the experimental period. Notably,
there were no differences in total chlorophyll c2 concentration
between still and flow controls (Fig. 2). The
flow treatment also showed a strong positive (logarithmic)
relationship between the number of zooxanthellae
per unit area and chlorophyll a concentration per
unit area (Fig. 3). Chlorophyll a per zooxanthella increased
only in flow treatments during the first 3 wk,
and then declined, while chlorophyll a per zooxanthella
declined over time in still treatments (Fig. 4). Chlorophyll
c2 per zooxanthella showed declines over time in
both still and flow treatments (Fig. 4). Fig. 5 shows that
there was little change in chlorophyll a:c2 in still conditions,
while flow conditions induced a rapid increase in
a:c2 during the first 5 wk, followed by a decline.