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Facts about Coral Reef Bommies
In marine ecosystems, a coral reef bommie refers to an isolated rocky outcrop or small pinnacle that rises up from the ocean floor.
Originating from the Australian term 'bombora', coral bommies are usually seen as separate submerged structures that have developed some distance away from sprawling reef systems.
Reef Bommies Can Be Hard or Soft Corals
Coral reef bommies can either be formed by hard stony corals (genus Porites), or they can be made of soft corals (gorgonin).
In addition, they can either be a cluster of corals or they can be a large single coral head.
The biggest coral reef bommies exist in Australia (especially the Great Barrier Reef) and some of them even break the surface.
Nonetheless, they all grow vertically from the sandy bottom and most of them are only a few metres high.
The primary reason that coral bommies are important is because they attract tropical fish and other marine life. Thus, a single bommie can create a safe habitat, shelter from predators, and a diverse mini ecosystem standing alone as a mound, column, or pillar.
Coral Reef Bommies and Scuba Diving
Most of the best bommie structures are found in areas with warm water and an abundance of strong sunlight, such as the dive sites in Australia and Southeast Asia.
These popular diving destinations feature an assortment of hard and soft coral bommies, even though the sensitive species often thrive better on the current-swept sides where they can filter food.
Bommies create interesting diving locations for scuba divers, freedivers, and snorkelers, because:
- A large, individual structure is very often easier to swim around.
- Coral bommies can be used as reference points during a dive.
- They attract cleaner fish, big shoals of fish families (e.g. schooling bannerfish), reef sharks, and sea turtles.
- Vertical pillars and pinnacles are ideal subjects for taking underwater photographs because they create a 360° tower of coral with radiant sunlight.
Where are Some Awesome Underwater Bommies?
Hard coral structures are formed by stony corals that secrete a calcium carbonate skeleton. After many years, the skeletons create some of the most amazing massive structures underwater - such as the bommies found at Ningaloo Reef off the west coast of Australia.
Soft coral bommies are not formed from a rigid skeleton. Instead, they are created by flexible fan-like formations (somewhat tree-like) made of gorgonin (a protein-based material.
Some of the prominent soft coral bommie structures grow well in places like Rainbow Reef (in the Somosomo Strait) and Komodo National Park within the Lesser Sunda Islands, in Indonesia.
Fun Fact: Even though it was recently discovered on the Great Barrier Reef (GBR), "Muga dhambi" is considered as being the largest coral bommie in the world. This enormous Porites coral structure measures over ten (10) metres wide and more than five (5) metres tall. Scientific estimates suggest that this massive bommie is more than four hundred (400) years old.