Optimal Temperature

[Charlesr1958]

So all animals will behave and react in captivity exactly as they would in the wild?

Yes, how could they react any differently? The same biology happens in our aquariums as it does anywhere else. If you step outside any reef parameter range an aquarium reef will react the same. In other words, you can't change genetics and an eons worth of evolution. In the case of larger, more intellegent animals, there may be some behavioral changes such as with fish or octopus, but their biological systems are not altered.

Chuck

 

[Charlesr1958]

Large swings in temperature on a regular basis will cause undue stress.

I would agree depending on what "large" means because I am constantly surprised while 40 feet down the reef wall to feel a sudden rush of hot (to me) water being swept across and down the reef during an outgoing tide. Obviously something the reef and its animals can handle and not something we can replicate in our aquariums without a huge effort. Again, a 24 hour swing of four degrees (F) (80-84) is perfectly normal.
I also like your slightly lowering that swing during the winter as the reefs also experience a slight cooling during the wet, cloudy monsoon season, for animals (coral colonies) that can be hundreds of years old, a single season is not a great deal of time and most likely plays a large role in their yearly biological cycle(s).
The next time I am snorkeling the shallows I will have to get a few photos of some coral species that make such areas their home as they see upwards of 90+ degrees on a clear sunny days and within an hour or so get cooled down to 80-82 when the tide rises. Corals are quite adaptable if given the time to do so and are more hardy than what most hobbyists give them credit for, all within reason of course.
Okay, I gotta go get wet! See ya!

Chuck

 

[Anonymous]

So all animals will behave and react in captivity exactly as they would in the wild?

Yes, how could they react any differently? The same biology happens in our aquariums as it does anywhere else. If you step outside any reef parameter range an aquarium reef will react the same. In other words, you can't change genetics and an eons worth of evolution. In the case of larger, more intellegent animals, there may be some behavioral changes such as with fish or octopus, but their biological systems are not altered.

Chuck

Okay, I guess we'll just have to agree to disagree then.

 

[Anonymous]

I do not see a problem with trying to replecate nature in the aquarium. I keep my tank at 78-80 in the winter and 82-84 in summer. My corals are doing fine, better yet, thriving. Large swings in temperature on a regular basis will cause undue stress.

I don't either. I think a successful tank can be kept at 84 degrees, or at 76 degrees, or lots of different temperatures, and that several degree variations throughout the day are probably not harmful, and neither are perfectly stable temperatures. If you peruse the TOTM features on any of the "big" online reef magazines, you will see lots of successful tanks being kept at lots of different temperature regimes. But wait! How is this possible? Dr. Ron wrote a paper that says...

I think the idea that natural daily variations in temperature are good for corals, and even necessary for healthy coral growth, is an extraordinary claim that requires extraordinary evidence. Corals experience all sorts of natural stressors in the wild that they tolerate, not require. Should we also be exposing our corals to air every day for a few hours to replicate the natural "work out" they get at low tide? I'm willing to listen to any experimental evidence that temperature variations result in better growth, color, etc., but so far I haven't seen any. I have seen lots and lots of tanks with healthy coral growth that have temperatures that don't vary more than a degree throughout the day.

 

[Anonymous]

So all animals will behave and react in captivity exactly as they would in the wild?

Yes, how could they react any differently? The same biology happens in our aquariums as it does anywhere else. If you step outside any reef parameter range an aquarium reef will react the same. In other words, you can't change genetics and an eons worth of evolution. In the case of larger, more intellegent animals, there may be some behavioral changes such as with fish or octopus, but their biological systems are not altered.

Chuck

Okay, I guess we'll just have to agree to disagree then.

+1

 

[Charlesr1958]

After a short search for any works done on this subject I was unable to find a "defining" study, although this topic is touched upon in many other studies such as the one I cited earlier. Sooo, when not able to offer hard core proof, I fall back and go ask an expert for his opinion, which in this case is Eric Borneman and I quote his reply to my question and the reason for my question:

Eric Borneman : " Lord. How are you or he defining "health?" Generally, any organism subject to subacute regular stress has a higher stress tolerance and are often "hardier" or, to use the proper term, more resilient. They absolutely need temp change for normal reproductive rhythms. I would respond by saying that I would argue that corals in the wild grow larger, faster and with denser skeletons as well as reproducing in the wild which, to me, is healthier, than what we have in tanks. As for the role of temperature, I am not aware of any study EVER looking at consistency of temperature and any coral "health" parameter, be it disease resistance, growth, reproduction, etc. There are papers what suggest corals that are subjected to greater variations in temperature are less susceptible to bleaching and this is probably due to the strain of zooxanthellae that is ideal for their location. The more thermotolerant strains show reduced bleaching suspectibility. But, not many people study the effects of constant temperature because there aren't any places on earth where the water temperature just remains the same. So, it would be up to the aquarium people to prove that and the burden of proof would be on him, not you. " END QUOTE

I am going to conclue my paritcipation by saying that "stable" temps or temps slightly lower than what is natural is NOT going to kill your corals, it will however make them more susceptable should an equipment failure cause a long term (longer than a few hours) rise in temperature, which is why when others do attempt a temp increase on corals that have been "stable" they report that their corals do not "look well" at all. Which is what I would expect to hear. So for those tanks with lower and "stable" temps, now you at least know the reason why your corals react badly to temp increases. Its simply because they are not used to it and for those whose tanks do see a temp swing of between 80-84/86, have no fear, its perfectly naturual, if....your corals have been acclimated (back to) it.

Chuck

 

[Anonymous]

I think you are picking and choosing your 'experts'.

I also don't think we disagree as much as you think we do. I think the basic sticking point is that I think that the dynamics of captive reefs are different than those of wild reefs.

 

[Charlesr1958]

No, not at all, the experts I chose or pick are those that I am familiar with and trust their experience and knowledge as well as having access to where I can pick their brains.

Dynamics such as water flow, constant planktonic food avialable and the like are of course different than a wild reef compared to our aquariums, my point is the biology of it all is not nor could be any different than as occurs in the wild. The same causes in the wild have the same effects in our aquariums. A coral is a coral regardless of where it is located, it can be nothing more or nothing less.

The effects are just more pronounced when enclosed in such tiny volumes of water that lack the various other habitats that make a coral reef possible. Quick example, dissolved nutrients have the same effect on our aquariums as they do on the reef, the sources are just different.

Take an animal or plant and put them into an artificially created habitat and no matter what, if you do not replicate their natural habitat's conditions, you are most likely going to fail in keeping them alive, healthy and.... resiliant to coin a phrase.

And....One more time!... Temp swings within a set natural range is perfectly acceptable as is stable unmoving temperatures, my entire "case" is that I know what our corals live in and are subjected to and to have the same conditions in an aquarium that they are naturaly subject to is not cause for concern and is even beneficial..... IF THE CORALS ARE OR HAVE BEEN ALLOWED TO ADAPT BACK TO IT if previously kept in a stable temperature.

Okay, thats it, you or anyone else may have the last word if need be as I have got to get work, which just happens to be about 40 feet underwater on pristine coral reefs.... lol Hope the week is good to you!

Chuck

 

[Anonymous]

my point is the biology of it all is not nor could be any different than as occurs in the wild.

So the much higher concentrations of heterotrophic bacteria and possibly pathogenic protozoans in aquariums vs. the wild couldn't possibly play a role in coral health?

Take an animal or plant and put them into an artificially created habitat and no matter what, if you do not replicate their natural habitat's conditions, you are most likely going to fail in keeping them alive, healthy and.... resiliant to coin a phrase.

We all keep corals in controlled environments that don't even come close to replicating water flow, planktonic food, scarcity of bacteria, etc. that occur on a wild coral reef, and yet these corals grow and reproduce just fine. You are making broad generalized statements to support your argument that aren't even true in a general sense.

And....One more time!... Temp swings within a set natural range is perfectly acceptable as is stable unmoving temperatures, my entire "case" is that I know what our corals live in and are subjected to and to have the same conditions in an aquarium that they are naturaly subject to is not cause for concern and is even beneficial..... IF THE CORALS ARE OR HAVE BEEN ALLOWED TO ADAPT BACK TO IT if previously kept in a stable temperature.

How do you know this is beneficial? Have you conducted controlled studies where you compare coral growth in genetically identical clones in stable vs. varying temperature regimes? Would you say that varying salinities are also beneficial to corals because they experience it in the wild? Why or why not?

Okay, thats it, you or anyone else may have the last word if need be as I have got to get work, which just happens to be about 40 feet underwater on pristine coral reefs.... lol Hope the week is good to you!

Chuck

I hope you don't mean "last word" for good. I find this discussion thought provoking and hope you continue to post.

 

[Anonymous]

I think you are picking and choosing your 'experts'.

I also don't think we disagree as much as you think we do. I think the basic sticking point is that I think that the dynamics of captive reefs are different than those of wild reefs.

 

[Anonymous]

Those tank kept corals that do not tolerate temp swings very well do so simply because they are kept at constant temps which only serves to weaken them.

Do you have any experimental evidence to support this assumption?

 

[Anonymous]

Theres no arguement that water flow is very important for any reef, but that has little to do with what temperatures the vast majority of our animals have evolved to be in.

Only if you completely discount the temperature dependence of solubility of gases and wonder whether corals would grow in such warm waters without additional the gas exchange that occurs in shallow waters...

Unless you have caribbean or Australian corals its a fair bet that your corals and fish come from the indo-pacific region, which just happens to be the center of all reef diversity and has an average year round temp of 82, as you move away from that center, the less species you will find.

Mean averages are great, for the general unwashed masses to ooh and ahh over. Folks like Shimek use that to their advantage (or they don't know any better). The trouble with means is that they have this funny little thing called a standard deviation. In this case, in both time and space. Additionally, you have to have a question of scale when it comes to time, with respect to both mean and standard deviation. You're crying to us about the relevance of your few years of data and a 27-28 mean in the Tropical West Pacific (or, for the true hotbed of diversity, the Western Pacific Warm Pool, >28, thats >82.5 degrees F for us dumb Americans). Do you think that species diversity existed a mere 20,000 years ago during the last interglacial, when the heart of the Western Pacific Warm Pool was on average 2-3 degrees C cooler (Yep, thats a mean of 77 degrees F) ? Assumptions bad. Actual data good.

 

[Anonymous]

my point is the biology of it all is not nor could be any different than as occurs in the wild.

So the much higher concentrations of heterotrophic bacteria and possibly pathogenic protozoans in aquariums vs. the wild couldn't possibly play a role in coral health?

I wonder if that talk I posted by Forrest Rohwer is still kicking around RDO...

 

[Anonymous]

my point is the biology of it all is not nor could be any different than as occurs in the wild.

So the much higher concentrations of heterotrophic bacteria and possibly pathogenic protozoans in aquariums vs. the wild couldn't possibly play a role in coral health?

I wonder if that talk I posted by Forrest Rohwer is still kicking around RDO...

http://www.marine.usf.edu/videos/2007-01-26.wmv

 

[Anonymous]

Much idiotic twaddle has been written, particularly by Charles Delbeek and Richard Harker, about maintaining coral reef animals at lower than natural temperatures...

Heh, I should probably just keep my mouth shut on this one...

Dr. Ron is very good at taking data from the wild and extrapolating it into a controlled captive environment. Charles Delbeek is very good at actually growing corals in captivity. I for one have no confusion about whose opinion to trust.

Awwww! I think somebody has a crush!

 

[Anonymous]

..in the Indo-Pacific, and since its a fair bet (check CITES export numbers) that the majority of corals collected and sold come from Indonesia and the Philippines and that most corals sold do not list their exact collection points with the rare exception recently of aussie corals being sold now.

Chuck

I disagree. I tend to know or am able to find out exactly where my corals came from.

Also Chuck, you know very well absolutely no stony corals are exported from PI. You may not have meant that but that is how it reads

 

[Anonymous]

I also guess your saying since I keep my tank at 75-77 I have been stressing my corals for 5+ years (when I dropped my tank temp) and all the great growth, thick skeletons and great color is actually an apparition?

"It's not as bad as we thought, it's worse" :roll:

 

[Charlesr1958]

Okay, nuff is a nuff...lol Yes, I made broad general statements as was my intention to answer the original question or concern about fluctuating temps. And I stand by my broad general statement that such fluctuations are perfectly normal and acceptable. The temp ranges I gave per indo-pacific corals is hard data and yet I also raised the question of why all of the species of corals are found in such temp ranges and are reduced in coral species and cover the farther away you get from that center? I thought the answer would be obvious. Which is simply that for the majority of coral species, such a temp range is optimal for them. If it wasn't, then explain to me why ALL of the indo-pacific species are in that temp range and not so in cooler reefs.
Now at the same time, while I am making general statements I also obviously failed to make myself clear when I speak of "natural" verses "artificial", that subject can be nit picked to death which a few are attempting to do. So in an attempt to clarify my meaning, Natural to me is the biological actions and reactions that occur regardless of WHERE they are, be it a reef or be it a tank. Of course there are circumstances that can be different, be it too much of one thing or not enough of another, possibly more pronounced in a tank, but the biology remains the same. At the same time, it also means to me that the animals have specific biological needs that have specific environmental ranges. Period.
As per corals doing well outside of what has to be an optimal temp range (80-84) I never said there were not cooler reefs, but I guarantee you that such reefs have less diversity, and that none of them have stable, stagnant temps. And yes, I also believe that slight fluctuations of any parameter adds to the coral's / reefs vitality, strength, call it what you will. I see salinity change from 1.022 - 1.024 over the course of a few days and back again, I also see it daily with my own system as water evaporates over the course of the night and then changes again when I do my once a day top off. I do so knowing full well that the reefs get the same every time it rains, and in the tropics, thats a fairly common event.

NOTHING on a reef is stable and yet everything thrives, so why is stagnant stability such a desirable thing? and reasonable fluctuations something to fear? THAT IS THE ENTIRE POINT I AM TRYING TO MAKE!

Oh, and I am glad to hear that stores or suppliers are starting to make it known where specific corals are coming from, and I still bet the majority of them come from indonesia and yes, the Philippines even though its illegal to export from the Philippines. Its nothing to rip up a reef here and take it back to indonesia and export them as indonesian corals, same with the jewelry trade, I've seen entire sections of reefs ripped up and piled onto the beaches to "cure" for a few months before being exported from....? Not to mention the numerous cargo containers of live corals that are found bound for Hong Kong and.... indonesia. Makes me wonder how many of you have Philippine corals...lol

Chuck

 

[Charlesr1958]

Those tank kept corals that do not tolerate temp swings very well do so simply because they are kept at constant temps which only serves to weaken them.

Do you have any experimental evidence to support this assumption?

Do you have any experimental evidence to support the assumption that placing an animal in unnatural stagnation is good for them?

Chuck

 

[Anonymous]

If we are going to play the 'expert' game (that is of course ignoring the pedegrees of some of those posting in this thread) Anthony says the exact opposite of Eric in the BOCP pages 161 and 162. But I hate the 'expert' game especially when the 'experts' bash each other like Shimek did to Delbeek in the 'article' linked earlier.

I am also a little confused, you talk about temp ranges as being optimal, but you are only taking into consideration the mean, not the actual ranges. If your point is natural is better, I am unsure why you aren't advocating letting your tank drop to 75 for a few months a year.

It seems you are basing the entire south pacific on what happens in Cebu, which makes little sense since we don't get any legal corals from that area, but more importantly, different areas have different temps.

No one seems to be saying that biological reactions are different on wild reefs or in an aquarium, rather that the conditions in an aquarium and a wild reef are different. In other words, the corals act differently because the conditions are different, and I think you are discount how different captive conditions are from wild conditions.

I think you are wrong about diversity on reefs that have lower temps for at least part of the year. PNG and Tonga have huge diversity and lower temps at certian times during the year that Cebu.

IMhO, stability is desirable because of the captive environment. So many things can go wrong so quickly and can snowball into really bad things so quickly, that it seems to make some kind of sense to keep things as controlled as possible to avoid 'crashes'.

The contention that stable and stagnant are the same seems like hyperbole to me - even with chillers and heaters, there are temp swings, and from the very beginning in this thread people have been talking about temp swings.

I think the point you say you are trying to make, that 'reasonable fluctuations are nothing to fear' is one that people don't have much of an issue with. What people do seem to have issue with, is dogmatic generalized statements that don't seem to have evidence to back them up, the ignoring of specific questions regarding your statements, and that you are basing conditions for all captive coral on Cebu, when in reality, most people have coral from many different places in their tanks.

Thanks for not going away from this thread.