Why are corals colorful?

pgreef · 11-03-2009, 06:52 PM

I know the zooxanthellae has the color. But why do corals exist in different colors? Some corals like favias, brains and zoas have very well defined multiple colors.

Some say flowers are brightly colored to attract bees so they will be pollinated. Some animals such as birds are brightly colored to attract mates.

What is the biological advantage to corals being brightly colored? Since they are immobile they can't attract mates. As far as I know they don't receive assistance by any other animal in breeding. You would think that being brightly colored would be a disadvantage since they would be easier to spot by butterfly fish and angles (unless they don't see in color). If zooxanthellae take on different colors based on the amount of light they receive why are some corals multicolored?

So what's the reason? It can't be just for our pleasure.

ZachB · 11-03-2009, 06:53 PM

Very interesting question and topic. Look forward to hearing the responses, as I've often wondered myself. Corals are very interesting critters.

kcbrad · 11-03-2009, 07:03 PM

I believe it's how the light rays are absorbed by the coral. Like how everything we look at is a different color because of how the light rays are absorbed/reflected by that particular object.

I think?! I took a physics of color class in college, and I think that's what I remember! :-)

tatted4ever · 11-03-2009, 07:04 PM

some good food for thought... You may have to bump this quite a few times pg.

youd almost have to be a marine bioligist to answer this

Av8Bluewater · 11-03-2009, 07:06 PM

God.

kcbrad · 11-03-2009, 07:07 PM

Why are different things different colors?

(Lansing State Journal, May 4, 1994)

When different wavelengths of light hit our eyes, we see different colors.
Light from the sun or light bulbs has many different wavelengths. This great mixture of wavelengths is commonly perceived as white. If the light hits an object - a road, tree, house, anything really - the object absorbs some wavelengths. Other wavelengths are reflected, and those are the ones we see.
When an object absorbs all wavelengths to a great extent, it appears black. If it largely reflects all light, it appears white. Objects that absorb only a fraction of all the wavelengths appear colored.
You can think of these phenomena in terms of the analogy: Light falling on an object is somewhat like rain falling on the ground. During a thunderstorm, some raindrops are quickly absorbed into the earth, but others hit so hard and fast they bounce off the ground.
Different materials absorb different wavelengths of light. Things that absorb light in the visible spectrum are called pigments. The chemical structure of each pigment determines which wavelengths of light it can absorb, and which are reflected.
Examples of pigments are: heme, which gives blood a red color; melanin, which gives skin a brown color; and chlorophyll, which makes plants green. Each of these compounds has a different chemical structure that absorbs different wavelengths of light, and thus, appear different in color.

5/4/94 - Why are different things different colors?

stepho · 11-03-2009, 07:11 PM

I am in the middle of watching some DVDs I got at super target. It is a series that appears to be from the 70s or 80s and it is all about oceans, reefs, and stuff of that nature. There is an episode about the cleaner crew (cleaner fish/shrimps) and how they set up their cleaning stations on brightly colored coral heads to attract customers. They then did a test where they removed the cleaner fish from an area to see how it would be affected... well all of the fish moved away or got isopods and other parasites. The corals had started to decline as well. So maybe it has to do with cleaning stations. A coral colony doesn't stand anything to gain directly by being used by as a station by the cleaner fish, but it would benefit from a diverse population of fish that keep the algae down,eat reef predators, etc.

Not sure how reasonable that is, just a guess really.

Dingo · 11-03-2009, 07:11 PM

how to color up your corals

inwall75 · 11-03-2009, 07:14 PM

It's not just in the zooxanthellae. Different species in different clades have different coloration but there's a lot more to it. In fact, if there are too many nutrients in an SPS system, your colorful corals will often turn brown as the zooxanthellae increases in numbers (sometimes to the point of poisoning the coral with too much Oxygen leading to a partial bleaching event). There are a lot of different proteins that make up color as well. Peridinen, Beta-Carotene would be the biggest. There's a lot to it.

how to color up your corals

EDIT: I GUESS YOU BEAT ME DINGO LOL

Dingo · 11-03-2009, 07:16 PM

the "natural" color of a coral is the color it reflects to attract the most beneficial zooxanthellae for its location.

Im currently writing a term paper on this for micro 413 so if you want to know anything ill try and help... or else have any good articles for me to cite it would be much appreciated!

11-03-2009, 06:52 PM	#1
pgreef Fire Goby Join Date: Dec 2008 Location: Algonquin, IL Age: 47 Posts: 1,344 Skin: Mint Karma: 15156	Why are corals colorful? I know the zooxanthellae has the color. But why do corals exist in different colors? Some corals like favias, brains and zoas have very well defined multiple colors. Some say flowers are brightly colored to attract bees so they will be pollinated. Some animals such as birds are brightly colored to attract mates. What is the biological advantage to corals being brightly colored? Since they are immobile they can't attract mates. As far as I know they don't receive assistance by any other animal in breeding. You would think that being brightly colored would be a disadvantage since they would be easier to spot by butterfly fish and angles (unless they don't see in color). If zooxanthellae take on different colors based on the amount of light they receive why are some corals multicolored? So what's the reason? It can't be just for our pleasure.

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11-03-2009, 06:53 PM	#2
ZachB Giant Squid Join Date: Oct 2008 Location: Earth Age: 32 Posts: 3,116 Skin: Mint Karma: 206163	Very interesting question and topic. Look forward to hearing the responses, as I've often wondered myself. Corals are very interesting critters.

11-03-2009, 07:03 PM	#3
kcbrad Giant Squid Join Date: Aug 2009 Location: Seattle, WA Age: 28 Posts: 9,558 Skin: Mint Karma: 9760675	I believe it's how the light rays are absorbed by the coral. Like how everything we look at is a different color because of how the light rays are absorbed/reflected by that particular object. I think?! I took a physics of color class in college, and I think that's what I remember! :-)

11-03-2009, 07:04 PM	#4
tatted4ever Horrid Stonefish Join Date: Mar 2009 Location: Itasca, Il Age: 28 Posts: 2,050 Skin: Mint Karma: 1009602	some good food for thought... You may have to bump this quite a few times pg. youd almost have to be a marine bioligist to answer this

11-03-2009, 07:06 PM	#5
Av8Bluewater Great White Shark Join Date: Aug 2008 Location: Old Town-22314 Posts: 2,679 Skin: Mobile Karma: 19776	God.

11-03-2009, 07:07 PM	#6
kcbrad Giant Squid Join Date: Aug 2009 Location: Seattle, WA Age: 28 Posts: 9,558 Skin: Mint Karma: 9760675	Why are different things different colors? (Lansing State Journal, May 4, 1994) When different wavelengths of light hit our eyes, we see different colors. Light from the sun or light bulbs has many different wavelengths. This great mixture of wavelengths is commonly perceived as white. If the light hits an object - a road, tree, house, anything really - the object absorbs some wavelengths. Other wavelengths are reflected, and those are the ones we see. When an object absorbs all wavelengths to a great extent, it appears black. If it largely reflects all light, it appears white. Objects that absorb only a fraction of all the wavelengths appear colored. You can think of these phenomena in terms of the analogy: Light falling on an object is somewhat like rain falling on the ground. During a thunderstorm, some raindrops are quickly absorbed into the earth, but others hit so hard and fast they bounce off the ground. Different materials absorb different wavelengths of light. Things that absorb light in the visible spectrum are called pigments. The chemical structure of each pigment determines which wavelengths of light it can absorb, and which are reflected. Examples of pigments are: heme, which gives blood a red color; melanin, which gives skin a brown color; and chlorophyll, which makes plants green. Each of these compounds has a different chemical structure that absorbs different wavelengths of light, and thus, appear different in color. 5/4/94 - Why are different things different colors?

11-03-2009, 07:11 PM	#7
stepho Clown Trigger Join Date: Dec 2008 Location: Kissimmee FL Age: 26 Posts: 2,013 Skin: Classic Karma: 650359	I am in the middle of watching some DVDs I got at super target. It is a series that appears to be from the 70s or 80s and it is all about oceans, reefs, and stuff of that nature. There is an episode about the cleaner crew (cleaner fish/shrimps) and how they set up their cleaning stations on brightly colored coral heads to attract customers. They then did a test where they removed the cleaner fish from an area to see how it would be affected... well all of the fish moved away or got isopods and other parasites. The corals had started to decline as well. So maybe it has to do with cleaning stations. A coral colony doesn't stand anything to gain directly by being used by as a station by the cleaner fish, but it would benefit from a diverse population of fish that keep the algae down,eat reef predators, etc. Not sure how reasonable that is, just a guess really.

11-03-2009, 07:11 PM	#8
Dingo Giant Squid Join Date: Aug 2009 Location: New Freedom, PA Age: 24 Posts: 4,758 Skin: Dark Karma: 18154430	how to color up your corals

11-03-2009, 07:14 PM	#9
inwall75 3reef Moderator Join Date: Sep 2003 Location: America Posts: 7,168 Skin: Classic Karma: 6810248	It's not just in the zooxanthellae. Different species in different clades have different coloration but there's a lot more to it. In fact, if there are too many nutrients in an SPS system, your colorful corals will often turn brown as the zooxanthellae increases in numbers (sometimes to the point of poisoning the coral with too much Oxygen leading to a partial bleaching event). There are a lot of different proteins that make up color as well. Peridinen, Beta-Carotene would be the biggest. There's a lot to it. how to color up your corals EDIT: I GUESS YOU BEAT ME DINGO LOL

11-03-2009, 07:16 PM	#10
Dingo Giant Squid Join Date: Aug 2009 Location: New Freedom, PA Age: 24 Posts: 4,758 Skin: Dark Karma: 18154430	the "natural" color of a coral is the color it reflects to attract the most beneficial zooxanthellae for its location. Im currently writing a term paper on this for micro 413 so if you want to know anything ill try and help... or else have any good articles for me to cite it would be much appreciated!