The Coral Corral

Posted in Under the Sea on March 16th, 2010 by MadDog
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Sometimes I get tired of chasing fish around. As a rule, I don’t do that, but we all know that rules are made to be broken. It happens most often at the end of a dive, when I should be moving in an orderly fashion toward the surface and I see that fish,  of which I have no image. Oh, yeah. It’s decision time. Check my air – okay; I always have plenty left at the end of a dive. I breathe mostly with my gills. That fish  is inevitably going down.  You are not supposed to end up your dive deeper than your last few minutes. That’s called a reverse-profile dive. It can build up too much nitrogen in your body and make your blood fizz like a freshly pulled Guinness.

So, what I usually do is say adios  to that fish  and slide up to five metres for my safety stop. Coral, however, requires no chasing at all, since it does not move. It may wave around, if it’s limber, but it stays firmly fixed to the reef and poses very nicely.

Therefore, today I’ll show you a pretty selection of corals that I corralled on our dive at Magic Passage last Saturday. I believe that you’ve seen all of these species here before, but these are much prettier pictures. The Canon G11 is making it so easy to get great shots that I’ll soon have to find new challenges. Hmmm. . . underwater fashion photography . . .

This young Divericate Tree Coral (Dendronephthya roxasia)  stands out nicely against the dark background:If you look carefully, you can see a diver in the distance.

I really like photographing D. roxasia  because there are so many beautiful colours available and they look completely different when the lighting changes. Sometimes they seem to glow as if lit from inside: The shot above accentuates the crispness of the coral image because the foreground and background are out of focus. It is a nice technique for “framing” your subject.

I am heavily into patterns. Something about them calms me. Corals make great subjects. This Diploastrea heliopora  is a good example:The individual polyps are about 1 cm in diameter.

Here is a shot of another specimen differing in colour and with a little more acute angle of the light:All of these images are more interesting if you click to enlarge. These regular patterns make mesmerising desktop backgrounds. Maybe a little too much so.

Here is one of the many wildly differing Leather Corals. This one is a species of Lobophytum:There are so many different leather corals that it’s difficult to identify a specimen from a single reference. I have only one book. It takes far too much time to dig into the web for a species name. That’s why many shots here give only the genus. I could not identify the species.

Here’s another one that is a mystery. It’s a coral of the Sea Whip mob, some species of the genus Ctenocella:They are very pretty and add a little action to the scene, waving around like wheat in a summer breeze. These are about as tall as full-grown wheat.

This outlandishly red coral is of the genus Lobophyllia:They are easy to spot, since they are about the reddest items on the reef.

Here is an interesting shot of the coral Goniopora djiboutiensis:I’m not sure what’s going on here. The white polyps appear to be the same species as the brownish ones in the background – the normal colour. I do not understand why this particular bunch of polyps on these old reef knobs are snow white. Maybe someone can explain. UPDATE: My Facebook friend Roshan Abeywickrama suggests that this may be G. lobata,  which I agree is a good possibility. I’m certainly no expert.

Finally, I give you one that I have been trying to photograph properly for years. It is very difficult to get the green to look natural. If you use flash, you have no chance. The colour is a combination of the pigments in the slimy coating of the very hard, brittle tree and the spectrum of light at that depth. The Tubastraea micrantha  has caused me much aggravation:I think that I’ve just about got it figured out. This is as close as I’ve come to reproducing the exquisite deep green colour that I see in this coral with my eyes at about twenty-five metres.

I’m almost there.

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Hold Your Nose – We’re Going Under!

Posted in Under the Sea on September 26th, 2009 by MadDog
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We’re going diving, but first I have to get this out of my brain:  How smart can Google be?

I Googled this (without the quotes) “how many people are killed by falling coconuts each year?” Out of the ten hits at the top, nearly all claimed that 150 are killed in an average year by falling coconuts. This is, you understand, of no little importance to me. I spend a lot of time out in my garden, which is lined with 25 metre coconut trees. I’m quite certain that a konk on the head with a coconut from that height would spoil my entire day.

Interestingly there was one hit from THE ISLOMANIAC ™ (islomaniac: īl-o-mā’nē-āk’ [noun] One with a passion or craze for islands) which claims that the number is purely mythological. And, as you’d expect, there was a rebutting comment exposing an obscure journal article as evidence supporting the quantity.

So, never mind that Google pointed me to pertinent information on the first hit, I’m nevertheless no more informed than I was before.

Still unsatisfied that Google is trusworthy to point me to useful information, I tried the classic: “how many angels can dance on the point of a pin?” Again, Google pointed me to some interesting pages, but failed to answer the fundamental question for me. It seems that nobody knows for certain where the question originated (though it is a very obvious  query and of huge significance), but Wikipedia has an interesting, if brief, history of it.

The most informative hit was number nine from the Journal of Improbable Research.  It’s titled Quantum Gravity Treatment of the Angel Density Problem  and, though it still fails to quantify the exact number of angels, it does set some handy upper and lower bounds. I was especially amused to be brought to the realisiation that, if angels are small enough, and are not massless, an angel sock-hop of sufficient popularity could produce a black hole!

Okay, enough philosphy. Let’s get wet.

Here’s how the fan coral looked without the flash:

Sea fan - natural light

Here’s how it looks with the flash:

Sea Fan - flash exposureFakey, fakey, fakey. Okay, that is the end of my nearly daily protestations of using artificial light for UW photographs. You must  be getting bored with that.

This is an interesting coral that we see on nearly every dive. It’s Lobophyllia hemprichii.  We call it, “That bright red stuff.” It is, indeed, red. You can see it glowing from a great distance:

Coral (Lobophyllia hemprichii)

Here is a thick branch of Staghorn Coral with an encrusting sponge (Echinochalina sp.)  eating it from the bottom up:

Encrusting sponge (Echinochalina sp. ?) growing on Staghorn Coral

You wouldn’t think sponges could be that viscious.

This critter is a Leopard Sea Cucumber, a kind of bech-de-mere (Bohadschia argus).  You can see some little bits of seaweed and coral sticking to it. They sometimes cover themselves completely with camouflage material. They are rather beautiful, if squishy, creatures with an astounding defensive weapon. The stickiest, nastiest substance on the planet.

Sea Cucumber ( Bohadschia argus)

I don’t have an image of my own to show you, so I’m filching (with attribution) this from OceanwideImages.com. The image is by Gary Bell:

Leopard Sea Cucumber by Gary Bell / OceanwideImages.com

If you poke (a no, no) or otherwise bother the Leopard Sea Cucumber, it will emit these seemingly innocuous white filaments. You could not be more wrong if you think that they are no bother. Pity any critter who gets stuck on these. They don’t sting, but they are nearly impossible to get off. You have to let the dry (and STINK) until they flake off.

Winding down now, I have one more shot for you. This is a perfectly ordinary coral (Goniopora djiboutiensis)  on the left. That’s not the interesting item in the image:

Coral (Goniopora djiboutiensis) on the left with a crayfish hiding on the right under the ledge

What is amusing it the lobster hiding under the ledge on the right. Sometimes it is easy to fixate on a particular specemine and miss something 30 cm away. I could have had a good chance for an image of a critter not yet in my collection, if I’d only noticed it.

Maybe next time.

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