do corals have a lifespan?

[clavery]

I mean, if they're closely related to animals, and we have lifespans, do corals? I know certain plants can die of old age, and certainly mammals/fish/insects do, so what about corals?

If so, any way to determine the age of a coral?

Just curious - might explain why certain corals just die off quickly - maybe they're just dying of old age.

Obviously, I have too much time to think about things!!!!

[DiggerDave]

Nice question, I would like to know to. Come on guys what do you think

[reeferkid]

i think they do but under ideal conditions i would guess its a heck of a lot longer than our life spans.

[maxvan1]

I dont think so, some anemones do though (but they have clones which have more clones, so the same gene stays for a while I belive, but I could be wrong?)

[Mud Shrimp Moe]

No, if they die in your tank you should not conclude it's just "old age."

This is second hand, per Dr. Ron Shimek, but they are effectively immortal. Not LITERALLY (they can be killed of course), but in practical terms they don't just die off of old age. And some specimens have been dated to very old ages. The probably with dating them in the wild, I suppose, is that they spread and propogate and the older specimens will eventually fall to an accident due to the law of averages.

[Mangas8282]

The problems with corals is that we have not identified genetic markers that allow us to phylogenetically classify them. Therefore, it makes it harder to determine ancestory and age of related species. Most of our classification comes from morphology, which after the coral has died becomes increasing harder. Corals consists of some of the largest organisms on the planets. In essence they are immortal. Corals heads can live, grow, die off, grow back, bud, and break off and form new colonies. These new colonies are most of the time genetically identical to the parent colony. I guess it comes down to a more philosophical question.....how do you define as organisms "self"? If a branch breaks off and forms a new colony, it is genetically identical, but is it the same organism? If so, then they do live forever. Idividually, if I am not mistaken, coral colonies can live for 100s if not 1000s of years.

[clowner33]

no

[clavery]

That's pretty cool if you think about it. Don't know that I'd want to live that long, but if they are somewhat immortal, imagine what they've "seen" so to speak.

BTW, I wasn't looking for an excuse for dying corals. I have lost a couple in my attempts to learn this insatiable hobby, but Im sure it was just due to my total lack of knowledge - all are presently doing well and growing like mad.

Gosh, do I want a bigger tank!!!!!

[this_reefer]

A coral is a colony of individual hydroids attached and supplement each other through tissue connecting each hydroid. Overtime usually as the coral grows the hydroids at the bottom will get shaded and eventually stop extending. You still might have tissue over the skeleton but no polyps. Eventually over time as the table becomes more dense the tissue will start to recede. Leaving bare skeleton and giving a chance for other inverterbrates, mollusks etc to attach. This will form into "rock" overtime!

So, basically, corals are neverending. They grow and grow producing new hydroids. As long as conditions are prime they will live.

Unfortunally as we know they are quite delicate that anything can wipe out a large colony! Like pollution, ships, trash etc etc. (of course this is out in the reefs not in our tanks!) But then in our tanks temp spikes or the like can wipe your colonies.

Thats SPS...LPS and Softies, well those I have not studied much and not sure if they have an expected lifespan. Although I have seen pictures of anemones almost the size of a VW! Leathers so big that it can cover you and Brains so large that are impressive!

So, I don't think they have a 10-20 years lifespan! More like 200-400 years!!

[Wee Man]

hydroids?

[Mud Shrimp Moe]

Yeah, I think the point is if a coral dies in your tank, there's no need to worry if it was you or it. It was you.

[Mariner]

I've heard several "experts" refer to corals as "theoretically immortal animals" (I believe that's an exact quote from Calfo).
Personally, I doubt that they are immortal in any "practical" sense. I would be surprised to learn that it could be scientifically proven that a single coral polyp, which is what we classify as "the animal," has ever lived more than a few decades on earth -- the constantly changing conditions on a reef, overshading, predation, etc. would not allow it, IMO. That said, COLONIES of polyps may reproduce indefinitely, and have probably done so in unending succession for very long periods of time.
my .02.
not worth much,
Mariner

[this_reefer]

Originally posted by Wee Man
hydroids?

Any of numerous characteristically colonial hydrozoan coelenterates having a polyp rather than a medusoid form as the dominant stage of the life cycle.

[beanpole209]

people are individual organisms as are single polyps people reproduce and make more people as do polyps you wouldnt say people live on forever because of there reproducing so you really cant say that about polyps in other words the coral or people as a whole may live til its destroyed but as individuals they have a life span just something to think about!!

[edsreef]

Any of numerous characteristically colonial hydrozoan coelenterates having a polyp rather than a medusoid form as the dominant stage of the life cycle.

Sounds impressive. But WRONG !! They're not hydroids.

[adrinal]

Certianly a colony of coral should be darn neer imortal.

[rtcpenguin]

Originally posted by Mangas8282
The problems with corals is that we have not identified genetic markers that allow us to phylogenetically classify them. Therefore, it makes it harder to determine ancestory and age of related species. Most of our classification comes from morphology, which after the coral has died becomes increasing harder. Corals consists of some of the largest organisms on the planets. In essence they are immortal. Corals heads can live, grow, die off, grow back, bud, and break off and form new colonies. These new colonies are most of the time genetically identical to the parent colony. I guess it comes down to a more philosophical question.....how do you define as organisms "self"? If a branch breaks off and forms a new colony, it is genetically identical, but is it the same organism? If so, then they do live forever. Idividually, if I am not mistaken, coral colonies can live for 100s if not 1000s of years. Great explanation/points.

[Reefmaniac1]

Originally posted by clavery
, but if they are somewhat immortal, imagine what they've "seen" so to speak.

Well, cnidarians are some of the oldest animals on the planet (and yes, they are animals...Kingdom: Animalia, Phylum: Cnidaria). So, considering that coral fossils date back at least 500 million years...they've seen the rise of just about everything else.

[this_reefer]

Originally posted by edsreef
Sounds impressive. But WRONG !! They're not hydroids.

So explain, don't just say its wrong!


What is a polyp?

A coelenterate, such as a hydra or coral, having a cylindrical body and an oral opening usually surrounded by tentacles.

What is a hydroid?

Any of numerous characteristically colonial hydrozoan coelenterates having a polyp rather than a medusoid form as the dominant stage of the life cycle.

[Biscutz]

I agree, why say "wrong" and not explain? Share, so all of us can learn.

[reefguru2]

Phylogenic markers are realy easy to make. As I am sitting here, I have some cooking for mice. Its just a restriction enzyme diegest. It just takes money, and time.

Andrej

[edsreef]

I agree, why say "wrong" and not explain? Share, so all of us can learn.
Hydroid - Any of numerous characteristically colonial hydrozoan coelenterates having a polyp rather than a medusoid form as the dominant stage of the life cycle.

Hydrozoan - Any of numerous coelenterates of the class Hydrozoa, including the freshwater hydras, hydroids, hydrocorals, and siphonophores.

Hydrozao - a class of coelenterates that includes various simple and compound polyps and jellyfishes having no stomodeum or gastric tentacles.

Hydrocoral - Any of various colonial marine hydrozoans of the order Hydrocorallinae, having a limestone skeleton and thus resembling the true corals.

You began by saying "A coral is....." as though you were providing a general description of how ALL corals work. I just think it's important that when we state emphatically, as you did, it is correct because others will read it as the gospel and if this forum is to help to educate we need to post responsably. What you describe is true of only a small subcategory of corals, which are not "true" corals; Hydrocorals - which include only two orders; Milleporina (fire corals), and Stylasterina (lace corals). So, if the topic were "Do fire corals and lace corals have a life span?", you would have been correct in describing thier anatomy. Sorry for being nitpicky, I just think a better general anatomical description for corals would have been in order and NO I'm not going to attempt it. Also, in general speaking terms, HYDROIDS are usually what we call those pesky little colonial critters that invade our tanks - do a google search for hydroids and see what comes up. HTH. :)

[Perureef]

well it all goes back to what constitutes an individual. polyps that clone forever are essentially immortal because they are the same from clone to clone. but when one is cloned, is it still an individual? This is why humans obviously arent immortal. not only do we die, obviously, but are children are only half of us genetically. It is rational to assume that the latter doesnt apply to coral polyps, but is it?
Let's not forget that coral do reproduce sexually, so there must be some mechanism that exists within species that prevents the population of said species from becoming to homozygous genetically and allows the establishment of new individuals with new gene variation (some time of apoptosis, for example (not sure if thats the right spelling)).

[this_reefer]

Ok, I agree with you at the begining I did start off my post the way you said, but if they would have FINISHED reading my post I clarified it saying I was talking about SPS.

I might have not been describing all corals but then I don't think you should come in saying that thats wrong and thats that! But educate people! If I was only describing a certain kind of corals say so!

Hydroids are hydroids...just cause we think of aptasias or other smaller critters in our tanks doesn't mean that thats what a hydroid is not nothing else! An aptasia IS a hydroid aswell!

[Mangas8282]

Phylogenetic markers are easy to make. I have done it before myslef. The problem with corals is that they have yet to find proper resriction enzyme which can isolate DNA that will serve as a proper marker. I spent a lot of time with phylogeneticists at my university that specialize in corals. Trust me, there is a lot research and money in the field. As for coral colonies not living for more the a few decades; they have measured growth rates of colonies over a 5 to 10 year period and by this been able to estimate how old colonies are. They have found colonies well over a 100 years.

[Mariner]

Mangas,
I respect the fact that you have a scientific background in this field. I do not have. But as a non-scientist I am constantly preturbed by scientific guesses being presented as facts. A lot of people who have been killing themselves taking Vioxx and vitamin E and relying on thousands of other scientific guesses as "facts" are equally preturbed.
Key words in your post: "they" "estimate" and "colonies."
Has anyone observed a single coral polyp live 100 years?
Who are "they" who found colonies 100 years old and how do they know they are that old? Is it just by extrapolating data from a 5 year observation of coral growth? Were the corals that they observed growing under the same conditions as those they estimated? Were the conditions in which the corals grew constant over the 100 year period? Was it assumed that coral growth would remain at a constant over 100 year period?
It may be that polyps live thousands of years. It would be cool if they did. But I'm done swallowing guesses as facts.
FWIW,
Mariner

[ReefGrl2k5]

I would agree. They are immortal.

[reefguru2]

Any regular restriction enzyme can cut coral. THere is no reason to assume that it cannot, they do not undergo DNA methylation like bacteria, and even so, you just remove the methylation portion of the enzyme and it works just fine. EcoRI will do just fine.

Andrej

[Perureef]

mangas, sounds fascinating, how exactly did they reach a one hundred year lifespan? why can't known restriction enzymes work in the case of corals? It would appear to me that they should