Green Acropora

Green Acropora from Blane Peruns TheSea
Photograph by Dan Rigle

Green Acropora – General Description and the Reason behind Their Coloring

When viewing the various shades of intense color associated with most green Acropora coral colonies, many would simply focus on the beauty of these complex life forms; however, the significance of the green color of these coral reef species goes well beyond appearance, playing a major role in their survival, reproduction and healthy growth.

Green Acropora Coral Species

There are about 368 different documented species of Acropora currently in existence, their colors ranging from bright pink to dark blue and purple. Green seems to be predominant in a number of corals that thrive near the surface of the water (at about 5-20 meters in depth, although this is not an extremely strict rule).
Green species of Acropora can range between wide variety of different shades of green, from the less intense color of Acropora Nasuta – a small sized, colonial coral that grows in clumps with branches of up to 0.5 inches in diameter – to the rich, vivid color of Elkhorn coral (or Acropora Palmata), an endangered species that predominantly inhabits the areas around Florida, Puerto Rico and the Bahamas.
The significance of the color can depend on multiple factors, including the depth at which the species thrives best and the amount of sunlight it usually benefits from in that particular region in order to enhance the photosynthesis process which allows it to survive.
Depending on the specific green Acropora species in question, some corals can change their color to adapt to their environment or grow tips and branches of other colors – such as blue, purple or brown – depending on the species’ particular needs.

The Significance of Green in Acropora Species

Researchers have determined that most colors play a major role in protecting Acropora corals from intense UV radiation coming from the sun. Also, coral colors are widely responsible for attracting mates, being a sign of the coral’s health.
The most important reason behind green colored Acropora, however, is due to the allowance of zooxanthellae cells of converting light to chlorophyll and inducing the process that allows the coral to manufacture its necessary supply of oxygen.
Depending on the amount of light needed for this process, Acropora species have developed distinct color patterns to absorb precisely the amount of light required and protect their populations from excess light that would, for instance, be absorbed through the use of darker color pigmentation.
The chemical structure of the pigment used by green Acropora corals is what gives them their own distinct shades, and while their existence can in some cases still be prolonged without excessive amounts of their green pigment, the bleaching effect that results from various environmental unbalances can often lead to the degradation and death of that specific coral.