Lifespan of corals

[BeanAnimal]

"Global Warming" and "Global Cooling" have occured numerous times. I would suspect that a "niche" is more like a passing moment in time.

Coral colonies that are thousands of years old would not shcok me. However, coral colonies that are tens of thousands or hundreds of thousands of years old would be another story. Climate change is certainly a part of our planet and niche environments simply do not last very long in scheme of things.

 

[MCsaxmaster]

<a href=showthread.php?s=&postid=11737889#post11737889 target=_blank>Originally posted</a> by BeanAnimal
"Global Warming" and "Global Cooling" have occured numerous times. I would suspect that a "niche" is more like a passing moment in time.

Coral colonies that are thousands of years old would not shcok me. However, coral colonies that are tens of thousands or hundreds of thousands of years old would be another story. Climate change is certainly a part of our planet and niche environments simply do not last very long in scheme of things.

Let's not confuse "niche" with a particular location. An organism's niche are those conditions in which it can survive (fundamental niche) or does survive (realized niche) and those functions it performs within an ecosystem. Without evolution a species fundamental niche does not change (though its realized niche may), even if the environment changes. For example, Acropora palmata as a species has been around ~3 million years. During ice ages it had a somewhat more restricted range than it does today. In particular, there are obvious refuges for the species in the Southern and Eastern Caribbean. During interglacial periods it spreads to higher latitudes. Six thousand years ago there was a huge, fast-growing reef of A. palmata and A. cervicornis off of Ft. Lauderdale. A palmata is limited to about 50 km south of that nowadays. A. cervicornis used to be, but it has recently spread back to these areas due to ocean warming.

 

[BeanAnimal]

Thank you for putting the word in the proper context for the subject matter.

So the species has adapted to different environments to survive. It may be traced back ~3 million years but today's specimen is not the same coral as that which was growing 3 million years ago. I.E. there is not a 3 million year old head of coral out there. Instead there are descendents that have of that coral that have adapted to the ever changing planet. Is my understanding correct?

 

[hammmerhead]

<a href=showthread.php?s=&postid=11732696#post11732696 target=_blank>Originally posted</a> by hammmerhead
Here is an old one. It was flawless as well.

Anyone have an idea how old this one is? I figured it was a pretty good find.

 

[timrandlerv10]

My BTA split. Again. And again. All of which were shortly after it split before I got it.

How old is the smallest one in my tank today?

(does that sound like a NetFlix commerical?)

seriously...lets assume it was created by fertilized eggs, God snaps his fingers, anything. Then a year later it split, and I bought one. Over the next year, it split then one of the splits split again. Are those three one individual? No. They're ramets? (is that ray or rah? meets or mets?) One of them has to be the oldest...but I feel funny applying my concept of 'birth' and age to the two new clones. As long as one BTA is alive, is he the first BTA created/evolved (lipservice paid to being PC for the month...)? Is he a bajillion years old?

 

[aninjaatemyshoe]

I'm definitely no geneticist but I know that in vertebrates there is a genetic age. The genetic age determines the point at which the body's cells will stop dividing. When you clone a vertebrate, the clone starts that the genetic age of the cloned animal. So, if you cloned an old animal, you would end up with a clone that wouldn't live very long.

For cnidarians that can propagate through asexual splitting, I would imagine that the presence of the genes for senility would prevent the animal from propagating in such a manner indefinitely. The clones of the coral or anemone would carry the same genetic age as the "original." For us, that would mean the captive propagation methods of such animals (which is only through asexual means) could not be sustained.

 

[MCsaxmaster]

<a href=showthread.php?s=&postid=11743858#post11743858 target=_blank>Originally posted</a> by BeanAnimal
Thank you for putting the word in the proper context for the subject matter.

So the species has adapted to different environments to survive. It may be traced back ~3 million years but today's specimen is not the same coral as that which was growing 3 million years ago. I.E. there is not a 3 million year old head of coral out there. Instead there are descendents that have of that coral that have adapted to the ever changing planet. Is my understanding correct?

There may have been some adaptation of the species over this time, but by and large the species has simply been able to grow in locations that provide the proper conditions. From this perspective, the fundamental niche has remained the same but the physical locations where that niche can be realized have changed.

Corals, like most organisms, reproduce sexually. Corals also reproduce asexually. While you can get patches of a given coral due to fragmentation and asexual reproduction, all genetically distinct individuals originated through sexual reproduction. A. palmata probably doesn't live to be more than a century or two most places, and most probably don't live more than a few decades, eventually getting trashed by a hurricane or something else. More is probably possible, but unlikely.

When I say the species has existed for ~3 million years I don't mean to imply that individual corals have existed that long. Our species (H. sapiens) has existed for ~100,000 years. As individuals die they are replaced by sexual reproduction, and the same is true in A. palmata; the only twist is they can be fragmented and reproduce asexually as well, whereas we can't.

 

[MCsaxmaster]

<a href=showthread.php?s=&postid=11744967#post11744967 target=_blank>Originally posted</a> by timrandlerv10
My BTA split. Again. And again. All of which were shortly after it split before I got it.

How old is the smallest one in my tank today?

(does that sound like a NetFlix commerical?)

seriously...lets assume it was created by fertilized eggs, God snaps his fingers, anything. Then a year later it split, and I bought one. Over the next year, it split then one of the splits split again. Are those three one individual? No. They're ramets? (is that ray or rah? meets or mets?) One of them has to be the oldest...but I feel funny applying my concept of 'birth' and age to the two new clones. As long as one BTA is alive, is he the first BTA created/evolved (lipservice paid to being PC for the month...)? Is he a bajillion years old?

Given that the anemone is splitting in half, why would you say one half is "original" whereas the other half is "new?"

In a case like this I think the only sensible thing is to say very clearly that the genotype of this anemone resulted from sexual reproduction X years ago but that these two clones were produced through asexual reproduction X months ago.

The reality is that, even if the anemone is very old the tissue it is made of is relatively young. The tissues in living organisms are constantly replaced. Thus, there is absolutely no way nor any practical meaning in trying to decide which of the two anemones was "original": both were and neither were.

 

[MCsaxmaster]

<a href=showthread.php?s=&postid=11745909#post11745909 target=_blank>Originally posted</a> by aninjaatemyshoe
I'm definitely no geneticist but I know that in vertebrates there is a genetic age. The genetic age determines the point at which the body's cells will stop dividing. When you clone a vertebrate, the clone starts that the genetic age of the cloned animal. So, if you cloned an old animal, you would end up with a clone that wouldn't live very long.

For cnidarians that can propagate through asexual splitting, I would imagine that the presence of the genes for senility would prevent the animal from propagating in such a manner indefinitely. The clones of the coral or anemone would carry the same genetic age as the "original." For us, that would mean the captive propagation methods of such animals (which is only through asexual means) could not be sustained.

That is true of senescent organisms, but not for those that don't senese. It appears some corals become senescent while others do not, thus one coral will eventually die of old age, no matter when it was fragmented, while another will never die of old age regardless of fragmentation.

 

[MCsaxmaster]

<a href=showthread.php?s=&postid=11744057#post11744057 target=_blank>Originally posted</a> by hammmerhead
Anyone have an idea how old this one is? I figured it was a pretty good find.

Hard to say precisely without a real good sense of scale, but I'll estimate it's about 1.5 m high. Typically this coral has a linear extension rate of 2-4 mm/yr which depends heavily on local conditions (e.g., they grow slower in the north where winter-time temps and light are low and faster in the south where winter is more similar to summer).

So, given a linear extension rate of 2-4 mm/yr and a colony 1.5 m high I'd estimate it is maybe 500 years old.

Chris

 

[rbursek]

Very interesting thread!! I respect all here, not like some threads, example, to put foam under tank, where some of the egos got way out of wack!!!!! Nice to read one without that, stayed on topic, and just use good questions to bring out more info. Thank you all for an interesting read!!!!!!!!!!!!
Bob

 

[chrisalmand]

It's not like one organism is living forever, it's a family. Each polyp on a coral is an INDIVIDUAL, independent animal.

 

[Aquarist007]

<a href=showthread.php?s=&postid=11762431#post11762431 target=_blank>Originally posted</a> by rbursek
Very interesting thread!! I respect all here, not like some threads, example, to put foam under tank, where some of the egos got way out of wack!!!!! Nice to read one without that, stayed on topic, and just use good questions to bring out more info. Thank you all for an interesting read!!!!!!!!!!!!
Bob

I agree with you Bob, I have been silently following this thread, in awe of the technical information that has been presented.
Scott

 

[greenbean36191]

Each polyp on a coral is an INDIVIDUAL, independent animal.

They aren't independent. That's what most of this discussion is about. They are genetically identical, in most cases their tissue is continuous between polyps, they share nutrients via an interconnected gut, they have interconnected nerves, etc. There's no discrete dividing line separating one polyp from another except in phaceloid species. Where we say one polyp starts and another begins is fairly arbitrary.

 

[JPMagyar]

<a href=showthread.php?s=&postid=11749981#post11749981 target=_blank>Originally posted</a> by MCsaxmaster
That is true of senescent organisms, but not for those that don't senese. It appears some corals become senescent while others do not, thus one coral will eventually die of old age, no matter when it was fragmented, while another will never die of old age regardless of fragmentation.

I am genuinely fascinated by this topic as its' not one that I have previously given any thought to, but one in which I am most interested now since I have an Heteractis Maginifica anemone that has split twice and one that I would love to continue to see splitting in the future.


Can you or anyone else on this thread recommend some reading that represents the latest research on coral and/or other invertebrate senescence?

Thanks a bunch,

joe

 

[MCsaxmaster]

<a href=showthread.php?s=&postid=11963169#post11963169 target=_blank>Originally posted</a> by chrisalmand
It's not like one organism is living forever, it's a family. Each polyp on a coral is an INDIVIDUAL, independent animal.

Just to add onto what Mike said, and the thread in general, if that were true then you would need to agree with these statements:

It's not like some sponges (poriferans) can live for hundreds of years, they're a family. Each cell is an INDIVIDUAL, independent animal.

It's not like some trees can live for thousands of years, they're a family. Each leaf, each branch, each root, etc. is an INDIVIDUAL, independent plant.

It's not like a nervous cell in my body can live for dozens of years, it's made of a family of atoms. Particular sets of atoms, which are replenished entirely about every 6 months, create and INDIVIDUAL, independent organism. A person 5 years old or 50 years old are really only about 6 months old--the average residence time of atoms that make up their tissues.

In corals that maintain tissue connections among polyps, which is almost all of them, the suggestion that each individual polyp is a seperate organism makes very little sense at all. For example, in these corals only larger colonies can reproduce, and only the polyps toward the center of the colony become competent to reproduce. Solitary polyps cannot and do not reproduce sexually. In fact, small colonies don't reproduce either, regardless of their age. The colony is the animal, the polyps are it's parts.

 

[MCsaxmaster]

<a href=showthread.php?s=&postid=11964832#post11964832 target=_blank>Originally posted</a> by JPMagyar
I am genuinely fascinated by this topic as its' not one that I have previously given any thought to, but one in which I am most interested now since I have an Heteractis Maginifica anemone that has split twice and one that I would love to continue to see splitting in the future.


Can you or anyone else on this thread recommend some reading that represents the latest research on coral and/or other invertebrate senescence?

Thanks a bunch,

joe

Good question. I don't have the studies handy, and I'm blanking on who did them now, but they are relatively recent (within the last decade). If I recall, genes for senscense were found in Acropora, but not Porites(???). I'd try to track these down with google scholar if you're interested.

From what I've heard from Daphne Fautin, reef anemones like H. magnifica or E. quadricolor can live quite a long time--a couple hundred years was normal if I recall. They also have pretty low rates of sexual recruitment, so those anemones that do establish themselves are normally there for a very long time, and are very slow to be replaced. For that reason, encouraging captive propagation of asexual clones of these species in captivity is the way to go. In areas where host anemones were collected for aquaria (e.g., Philippines) there are no more anemones nor any clownfish. Once they are removed, they are gone, at least for the foreseeable future.

So since you've got an H. magnifica splitting, take good care of it. We need more of that kind of thing

 

[SuperNerd]

Okay so then if a coral can live 100 years does that mean that each individual polyp theoretically will also live 100 years starting from its "birth?"

 

[MCsaxmaster]

<a href=showthread.php?s=&postid=12036595#post12036595 target=_blank>Originally posted</a> by SuperNerd
Okay so then if a coral can live 100 years does that mean that each individual polyp theoretically will also live 100 years starting from its "birth?"

If the primary polyp, the first polyp produced when the coral settled, survives 100 years then yes, it has survived 100 years. However, if it doesn't there's still no legitimate reason to claim that the coral is less than 100 yrs old. How old do you think many of the cells in your body are? How old do you think your tissues are? Corals replace tissues/polyps as they senesce, just as we replace cells/tissues in our body.

 

[SuperNerd]

<a href=showthread.php?s=&postid=12036865#post12036865 target=_blank>Originally posted</a> by MCsaxmaster
If the primary polyp, the first polyp produced when the coral settled, survives 100 years then yes, it has survived 100 years. However, if it doesn't there's still no legitimate reason to claim that the coral is less than 100 yrs old. How old do you think many of the cells in your body are? How old do you think your tissues are? Corals replace tissues/polyps as they senesce, just as we replace cells/tissues in our body.

Does this mean that each cloned/replaced polyp will live out the predetermined lifespan of the original mother colony polyp?

I read Xenia can live for 7 years. Does what you say theoretically mean each new xenia frag will live for an additional 7 years?