Patch reefs on the Great Barrier Reef, Australia

Clown fish staying close to their home, a stinging sea anemone for protection from predators.

Spur and Groove formations in the coral reef, GBR, Austral

Most people have heard of the GBR but very few know the geographic features that are unique to barrier reefs. A true barrier reef has 4 basic zones: back reef; rubble zone; reef crest; and fore reef. The back reef is an area of low energy, as it is protected from ocean swells by the reef crest. There is often a network of small patch reefs here that eventually give way to seagrass beds the farther away from the reef crest you go.  The rubble zone is also behind (landward of) the crest but experiences much more turbulence from the waves breaking over the reef crest. This area often appears barren as the bottom as it is completely covered with broken off pieces of dead coral.  The reef crest is the high energy zone of the reef. Fast growing branching corals such as Acropora sp. thrive in this area and are the main suppliers of the "rubble" in the back reef.The fore reef is built upon the drowned remnants of previous reef crests that formed when sea levels were lower. The most striking feature of the fore reef is its characteristic