I just got back from vacation. While there, I did a lot of snorkeling. Swam with the turtles, fish, sea cucumbers, octopus, and lots of other creatures!

I've always wondered something - the coral out on the coral reefs are always vibrant, brilliant colors. You see reds, oranges, greens, blues,.... But, when the same coral washes up on the beach, it's always white. Occasionally, you may see a tinge of pink on a piece or two, but it's mainly white. Why is this? I decided to find out. And, I thought I'd also share my findings with all of you.

The following is from a person at the Coral Alliance (what sounds like a wonderful organization that's dedicated to keeping the Earth's coral reefs alive - look at the website listed below):

quote:

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Hi Linda,
I don¹t know if you've already found your answer by looking on our website, but just in case you haven't, I thought I'd reply.

What gives corals their beautiful colors are zooxanthellae...little algae that co-exist inside the coral polyps. For more details on how and why, please see http://www.coralreef.org/coralreefinfo

What you are finding on the shore are the dead skeletons of the corals. The coral polyps create a hard skeleton that the soft polyps live in. When the polyps die, the tissue dies and all that's left is the white skeleton. That's why you don't find colored pieces.

When you read about "coral bleaching" because of El Nino and ocean waters that are too warm, that is because for some reason not totally understood, when coral polyps become stressed, they expel the zooxanthellae. The coral polyps are fairly transparent, so without the colored algae, you can see the skeleton and they look white. If the stress doesn't last too long, they may allow the algae back or may even take in a little different algae (adjusting to their new water temps) and thus, survive. But if they don't take back the zooxanthellae, they'll probably die and stay totally white...that is until a different type of algae takes over....not a good kind. A smothering kind that doesn't help the coral to live. Not a good thing.

I hope this has helped. There is a whole lot more information on our webpage. Enjoy.

Cheers,
Marty

Marty Dawson
Dive Industry & Travel Coordinator

CORAL - The Coral Reef Alliance
Branch Office
1708 Catalpa Rd.
Carlsbad, CA 92009

Phone 760-603-9115
fax 605-238-1954
email MDawson@coral.org
website coralreef.org

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Now, we know!

[ 04-25-2002, 12:22 PM: Message edited by: Linda1 ]

I think you are going to feel really dumb when I tell you this Lindal, but I believe I heard that the washed up coral is white because the washed up coral is DEAD!

Ummmm...that's what Marty said in the post I quoted above

quote:

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What you are finding on the shore are the dead skeletons of the corals. The coral polyps create a hard skeleton that the soft polyps live in. When the polyps die, the tissue dies and all that's left is the white skeleton. That's why you don't find colored pieces.

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I don't feel dumb at all, actually. I kinda thought it was a valid question.

[ 04-25-2002, 05:59 PM: Message edited by: Linda1 ]

Many of the coral reefs now spend some time above the high water mark because of the ever changing coastlines around the world. This is the reason that some of the top sections of reefs are now white. It has made such a big difference to the 'house' reefs which can be snorkled around the world.

The el nino had a dramatic influence on all coral reefs as it only takes a 1 degree temperature change to kill off the coral zooxanthellae.

I'm pleased that you had the chance to experience the wonderful diversity of a coral reef while the opportunity still exists Linda. They are decreasing rapidly, especially the ones within easy reach of the shores.

[ 04-26-2002, 01:01 AM: Message edited by: izzi ]

Coral like all objects in space really do not have color. Objects in space are all devoid of color, it is just your brain intrepreting the wavelength of light bouncing off the ...thing-in-itself out there....

izzi, I find it sad that the coral reefs are disappearing, too. They are such beautiful creatures - I hope that we come to our senses soon and learn that they need to be protected. They're not just pretty things out in the ocean; they serve a purpose in the ecosystem. It's important that we not let them all be destroyed.

I haven't had a chance to look at all the website Marty listed. But, from what I've seen so far, it looks like this is a good organization that's dedicated to educating people about the coral.

Sorry Linda, I'm really not the smart aleck I sounded like. I just whipped through your post quickly and thought you actually wanted to know. Boy is my face red!

Oh dear, jub! I had a small apology tapped out for you to post for Linda late last night (my time)...knew it must be something like that! But...I ERASED it! Have to do your own "mea culpa's" 'round these parts! You're still ok in my book!

Don't worry, jubjub's ok in my book, too.

Thanks Lindal!