Here's some good reading.....
The Silent Sentinels - the Demise of Tropical Coral Reefs
http://www.sbg.ac.at/ipk/avstudio/pierofun/reefs/ch2.htm#fig2-3
The Silent Sentinels - the Demise of Tropical Coral Reefs
http://www.sbg.ac.at/ipk/avstudio/pierofun/reefs/ch2.htm#fig2-3