Brain Coral, Author Alexander Vasenin
Meandering hard coral, Author:Johnmartindavies
Plate coral (Mycedium sp) credit: James Oliver (http://www.reefbase.org)
A sandy lagoon dominated by soft corals credit: Mark V. Erdmann (http://www.reefbase.org)
The reef flat dominated by branching and table Acropora, credit: Mark V. Erdmann (http://www.reefbase.org)
Hubbard, D.K. (1997). Reefs as Dynamic Systems
These threats are in addition to natural stresses that have always existed on coral reefs such as storms, freshwater inundation and seismic and volcanic events.
Outbreaks of the corallivorous crown-of-thorns seastar Acanthaster planci (COTS) represent one of the greatest disturbances to coral reef ecosystems in the Indo-Pacific, affecting not only coral reefs but also the coastal communities which rely on their resources.
At normal population densities, COTS play essential roles in the food webs of coral reef ecosystems. However, when outbreaks occur and their population density greatly increases in relatively concentrated areas, COTS become a problem. - Moutardier et al., 2015