Friday, December 28, 2007

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

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)


ria said...

Wow, wonderful facts and photos! Thanks for sharing!

Would be great to get a positive ID on the coral you marked as Favia. This flourescing coral is quite commonly seen on many of our sourthern shores.

My notes indicate Favia has intratentacular division: parent polyp generally divides into two equal sized daughter polyps forming a figure eight, and these are equally spaced throughout the colony. I'm guessing, closeups of this feature would help confirm?

The coral marked as Symphyllia sp. is probably indeed a mussid (Family Mussidae) but I still don't have a clear idea of how to distinguish Lobophyllia from Symphyllia. Would be good to get some idea of this and a confirmation of your id as this coral too, is regularly seen on our southern shores.

The coral marked as Trachyphyllia geoffroyi is probably a member of Family Pectinidae.

Trachyphyllia geoffroyi is a single polyp with many folds. While Pectinidae have many smaller polyps with walls forming a meandering, maze-like pattern. A closeup of the actual skeleton structure will probably help in the id.

I have only seen Trachyphyllia geoffroyi on Beting Bronok. Members of Family Pectinidae, however, are regularly seen on bigger reefs like Semakau, Hantu and Sisters.

ria said...

Oops, I missed the Diploastrea id. This might not be Diploastrea.

I saw one that looked like Diploastrea on Pulau Jong and Jeffrey Low helped confirm that it might be right. Diploastrea is quite distinct, especially if you have a closeup of the skeleton structure.

A photo of this coral was posted on wildfilms

And a higher res photo is on flickr

Mountain & Sea said...

Thanks Ria. I missed my Classroom lessons due to overseas assignment, and jumped into the field. I certainly missed alot of important points. Will update the blog. Have another assignment to complete for this Coral Workshop.

SJ said...

From what I gathered from a book (Corals of Aistralia and the Indo-Pacific by Veron), Symphyllia seems to have a grove along the top of the 'walls'. Lobophyllia doesn't seems to have that. Correct me if I'm wrong.

ria said...

Thanks SJ! Yes, I do have that feature in my notes too, more specifically: Symphyllia USUALLY has a groove along the top of the walls.

I'm looking at Veron "Corals of the World Vol 3" and Lobophyllia hataii seems to have a groove along the top of the walls and looks very similar to Symphyllia radians. Photos of both these corals look like what TC has on this blog.

Both species are recorded for Singapore from "A First Look at Biodiversity in Singapore".

The best thing would be to get a more definitive id from Jani. And perhaps some additional features that help us distinguish between the two, at least for those found in our waters.

Mountain & Sea said...

Thanks to Ria and SJ. Similarly, I was looking at the middle ridges of my photos, but with limited literature, the specimen seems to look like Symphillia than the Lobophyllia. Notwithstanding, have written to Jani for assistance in the IDs.

ria said...

Oh no. I looked some more at the books and there are some Platygyra that look similar, with a groove along the walls as well. Sigh.

Yes, it's best we ask the expert for help in this.

Thanks TC for sorting this out.

Fried Tempeh said...

Hey TC,

Great blog! I love the fluorescent photos! They turned out so pretty!! Great job! BTW, I went thru the photos on your Flickr account. Do take a look, I left a number of comments!

Hmm yes, Picture 5 is not Trachyphyllia but Pectinia. Trachyphyllia has very large mantle (the fleshy polyp bit) and the skeletal structure I find resembles more closely to a Mussid but without the exert septal teeth. Pectinia, on the other hand, the SKELETON is very jagged looking and has very irregular high structures formed by the septo costae. They're the coral I mentioned during the classroom session (I know u missed it unfortunately!) that produces a lot of mucus so if u gently touch it it's highly slimy. Picture 7 is not Diploastrea. It is a Faviid but I can't tell what it is from the photo (my guess would be either Favia or Montastrea).

OK, Lobophyllia vs. Symphillia. Yes, these 2 genus can be hard to tell apart...Simple way to tell the difference is that for Symphillia, when u trace the ridges, it never really meets up...whereas Lobophyllia if you trace the ridges it will close up & form loops and there are gaps between the loops of ridges. Hmm, I hope you get what I mean. i.e. Lobophyllia have SEPERATE WALLS whereas Symphyllia have FUSED WALLS.

Hope this helps!


Mountain & Sea said...

Thanks Jani for your patience and guidance.
What can I said after all these, is that I definitely know my coral better.
TC Tan