Polyp bail-out induction
To induce the polyp bail-out response in Pocillopora acuta , a
hyperosmotic environment was established by gradual addition of
high-salinity seawater (48‰). In experiment I, seawater salinity
increased from 35‰ to ~43‰ after 12 h and to
~46‰ after 24 h in the treatment group. Morphologically,
no obvious signs of a stress response were seen at 12 h in the treatment
group. Polyp bail-out was observed at 24 h, at which 30 – 50% of the
polyps were found detached from the skeleton (Fig. 2). For the control
group (salinity change < 0.5‰), no sign of polyp bail-out or
other stress response was observed at any time during the experiment
(Fig. 2).