Sorry Glen, only just seen this.
Old joke... What did the doggy say when it sat on the sandpaper ?
shrimper wrote:Ruff.
Does your Alan know how to regenerate corals and other marine organisms that form rocky ridges just below the surface of the sea?
The corals can regenerate themselves provided the conditions revert to the optimum. It is the hard
(stony) corals that create the reefs. To see this in action go to
https://www.youtube.com/watch?v=0UlnRnHWFqUfrom about 1m 40 sec in.
When you go to some tropical paradise (further than Hest Bank) the sand on the beach has been
created by Parrotfish which browse on the stony corals and pass out the waste as coral sand.
http://www.sandatlas.org/parrotfish-makes-sand/Hope this helps !