The level of water on the reef top decreases dramatically,getting ever shallower,and going from a stable environment,to ever changing hostile one.

It's almost as though some mighty force has lifted the reef right out of the water,these are extreme conditions.As the exposed corals start to heat up ,the tiny polyps retract inside their stony skelectons for protection,then they secrete mucouscan,it acts as sunscreen, and there is no skimping on quantity,am area no larger than the size of a coffee table can produce five meters of the stuff.As the tides retreat to the edge of the reef,it cuts off pools of water,for most animals like the sea cucumboers and starfish,the best way to stay alive is by taking refuge in these rock pools.