Coral Fluorescence and other attributes

Coral Workshop in Semakau (25 Dec 2007)
(Kindly provide correct ID of coral if named wrongly. Much appreciated)
For the rest of the pictures please follow this link http://www.flickr.com/photos/tan-tc

As the workshop was held in the evening, the first few coral that we came across was fluorescing in a beautiful green glow! Eventually we will get to see other corals and even Peacock Anemone glowing in the dusk light.


Picture 1 - Favia sp.

The phenomenon of FLUORESCENCE is when matter of higher energy is being absorbed by a substance, and in term being released by that same substance at a lower energy level. For CORAL FLUORESCENCE, the higher light energy (blue colour) is being absorbed by the Coral, and released in a lower light energy (green or red colour). Thus coral that may appear dull in the daytime, may emit myriad of colours during the dusk period.

Jani (our workshop instructor) explained that this is the normal reaction of such coral during certain time of the day as a form of “sun block” to reduce the animals from receiving harmful ray (ie. UV light which is at the other end of the visible light spectrum).
It is also known that younger Coral (Coral Recruit) tends to radiate more than the older ones. Takeing advantage of this behaviour, scientist has used this behaviour when they are out looking for recruit for their research. Of course, in the aquarium trade, to make their coral exhibits more interesting, the tanks will always be bathed with UV light.

Dr Charles Mazel - a leading investigator into Coral Fluorescence, said that it is possible for coral to fluorescence without any known reasons. The phenomena of Coral Fluorescence is still full of mystery. Is it an indicator the health of the coral; for spawning reason; ward off predators. Scientists are still wondering!

Picture 2 - Brain Coral (Symphyllia sp.)

Picture 3 - Turbinaria

In this picture below, it can be clearly seen that those polyps that are out of the water, the glow tends to center in the center of the Calyx (the calcium cup that the polyp lives), but those in the water has a more brilliant glow. The reason is that only the lived part of the coral (polyp) is the one that glow, and not the Calyx.

Picture 4 - Closed Up of the Favia sp.

Picture 5 - Carnation Coral (Pectinia). Totally submerged in water, the polyps are out and fluorescing.

We came across these two corals, with one of them “bald” on the left side. I took a compass bearing, and interestingly it pointed to the East. This is co-incidental or maybe this specimen does not like the harsh morning ray, but then how many low tide coincide with the Sun rise, and in this spot.

Picture 6 - Faviidae

Referring to BALDING of Coral, usually the balding occurs at the top of a coral mass. The primary reasons are
· Settling of Sedimentation
· More prone to physical contacts with other floating objects
· Direct Sunlight when exposed during low tide

Picture 7 - Faviidae

An interesting observation was pointed out by Jani, and that is to infer the wave energy of the shore by observing the type of Corals that grow in that region. Boulder like Corals (eg. Porites, Montipora) tend to indicate higher wave energy shore, and more so if there is an absence of the Branching types of Corals (eg Acropora)

Estimating the age of coral, is by looking at the size of the coral and estimating the thickness of the coral from an imaginary centre point of the coral mass. As coral grows about 1 to 2 cm a year, then the coral below is about 15 years old. Some of the bigger ones are older than you and I!

Pictue 8 - Symphyllia sp.

Beside the Coral that was Flourescing, this uprooted Peacock Anemone was also radiating in bright orange.

Semakau is blessed with all these types of corals and more. And we are blessed to have Semakau. And all the more we have to be mindful of our heritage, as these once lost will be hard to replace.

(Special thanks to Jani for her keeness to teach us, and Luan Keng for organising)