Common Misconceptions In the Hobby

[greenbean36191]

Photosynthesis gives corals at least part of their requirements for C, but doesn't meet their requirements for N.

I guess this could be a misconception itself.

A lot of people think all their corals need is a strong light and their zooxanthellae feed them. Zooxanthellae produce carbohydrates for the coral. How much of a corals C budget this sugar provides varies from ~0-115%. However, that's the minimum carbon required to stay alive, not to grow or reproduce. To do that requires other sources of C either from the water or food.

Like any animal, corals need more than just sugar to survive on too. Namely they need a source of protein, which the zooxanthellae don't provide. They can meet their N requirements by taking up dissolved organics such as free amino acids or by eating, with the latter being more important in most species. Some corals use neat tricks like farming bacteria to meet a lot of these needs, but not all can and it's not clear how much of the N budget can be supplied that way.

 

[Peter Eichler]

<a href=showthread.php?s=&postid=12469054#post12469054 target=_blank>Originally posted</a> by greenbean36191
I guess this could be a misconception itself.

A lot of people think all their corals need is a strong light and their zooxanthellae feed them. Zooxanthellae produce carbohydrates for the coral. How much of a corals C budget this sugar provides varies from ~0-115%. However, that's the minimum carbon required to stay alive, not to grow or reproduce. To do that requires other sources of C either from the water or food.

Like any animal, corals need more than just sugar to survive on too. Namely they need a source of protein, which the zooxanthellae don't provide. They can meet their N requirements by taking up dissolved organics such as free amino acids or by eating, with the latter being more important in most species. Some corals use neat tricks like farming bacteria to meet a lot of these needs, but not all can and it's not clear how much of the N budget can be supplied that way.

Did you just bring up coral uptake of free amino acids in the misconception thread?:eek2: :lol:

 

[greenbean36191]

Yes. I didn't say anyone should dose them though or that amino acids are any more useful or preferred to other forms of N such as nitrate. I won't even get into that because I don't think the science is there.

 

[Peter Eichler]

<a href=showthread.php?s=&postid=12469692#post12469692 target=_blank>Originally posted</a> by greenbean36191
Yes. I didn't say anyone should dose them though or that amino acids are any more useful or preferred to other forms of N such as nitrate. I won't even get into that because I don't think the science is there.

I know man, I was just giving you a hard time. The evidence suggesting we need to does amino acids seems to be pretty in line with the evidence for dosing iodine. That evidence boils down to, "it's in our corals and supplements are available so we should dose it!"

 

[toaster77]

just to follow up on greenbeans posts, yes every organism needs a carbon source, nitrogen source, phosphate source and sulfur source, these elements are required to synthesize the basic building blocks of life - DNA, proteins, etc.

In addition to those, they need particular elements/metals (e.g., magnesium, iron, zinc...) and depending on the organism certain vitamins as well. many microbes have the ability to synthesize most all amino acids and vitamins, so if you supplement them what they will do is just shut down their own biosynthetic pathways. as long as the basic building blocks are present in sufficient amounts in the water or provided by symbiotes they will be ok. and yes, the photosynthetic zooxanthella will provide glucose, but as pointed out other nutrients are for sure needed as well. also in higher organisms, for example us humans, we cannot biosynthesize certain amino acids or vitamins so that is why we need to eat and ingest them.

so all in all i do believe there is benefit to having some extra nutrients floating around because after all the organisms need them to grow and proliferate. i think it is finding that delicate balance where we promote the growth of corals but not at the cost of the nuisance species taking over that we are all striving for.

 

[Paul B]

Paul lets take your point a little further--you have a skimmer that has taken all it can from your reef tank--then have you not robbed that ecosystem of everything that is good for your corals and inverts--so in fact you have overskimmed

I disagree. Only dissolved organics will be removed and a little other constituites of the water by accidently being on the surfacce of the bubble when it is skimmed. Skimmers work because there are certain molocules that have two parts, one part is water loving and one part is water hating. These molocules form bubbles when air is passed by them because the parts of the molocules that love water stay on the outside of the bubble while the water hating parts of the molocule form the inside of the bubble. Luckilly for us, these molocules make up a good part of disolved organics.
Our animals do not need DOC. When all of the DOC is removed the skimmer will stop skimming.
By the way we used to call protein skimmers "foam fractionators"

 

[toaster77]

<a href=showthread.php?s=&postid=12469924#post12469924 target=_blank>Originally posted</a> by Paul B
I disagree. Only dissolved organics will be removed and a little other constituites of the water by accidently being on the surfacce of the bubble when it is skimmed. Skimmers work because there are certain molocules that have two parts, one part is water loving and one part is water hating. These molocules form bubbles when air is passed by them because the parts of the molocules that love water stay on the outside of the bubble while the water hating parts of the molocule form the inside of the bubble. Luckilly for us, these molocules make up a good part of disolved organics.
Our animals do not need DOC. When all of the DOC is removed the skimmer will stop skimming.
By the way we used to call protein skimmers "foam fractionators"

I think someone needs to step up and do the experiment - analyze the molecular contents of skimmate.

Actually this could be done in a fairly controlled manner - setup a mock tank with saltwater, add nutrient X, turn on skimmer for Y hours, measure amount of nutrient X in skimmate.

 

[D to the P]

Yeah I've seen in some books skimmers called foam fractionators. Of course they had to changed that to protein skimmers because of a new product that was going to sweep the nation like the micro wave over, Skilters! And Skilter is so much more palatable than Fractionilter or Foam Filternator. :lol:

Sorry Paul, didn't mean to call you out on your age.

 

[Peter Eichler]

<a href=showthread.php?s=&postid=12470020#post12470020 target=_blank>Originally posted</a> by toaster77
I think someone needs to step up and do the experiment - analyze the molecular contents of skimmate.

Actually this could be done in a fairly controlled manner - setup a mock tank with saltwater, add nutrient X, turn on skimmer for Y hours, measure amount of nutrient X in skimmate.

Eric Borneman has done a little skimmate analysis here.

http://forum.marinedepot.com/Topic52254-9-1.aspx

 

[Aquarist007]

I have reread Randy's article on dissolved organics and since I don't see nitrates and phosphates there I am going to assume they they are not dissolved organics(by definition they are not but I was just curious to see if they were lumped together in the case of salt water chemistry)

Two questions Paul
one, are we to assume that nitrates and phosphates are not removed by foam fractionators and or other essential substances

two, how do we know that everything from inverts to corals don't use DOC's in one form or another

 

[Aquarist007]

<a href=showthread.php?s=&postid=12470109#post12470109 target=_blank>Originally posted</a> by Peter Eichler
Eric Borneman has done a little skimmate analysis here.

http://forum.marinedepot.com/Topic52254-9-1.aspx

boy--that thread was quite a read--its amazing how academics are ready to pouce all over each other on their scientific methodologies

interesting that Borneman did find plankton, nitrates and phosphates in the skimmates along with the organics. It was also interesting on the finding of coral mucous etc---something he admited was used by bethnic life in the aquarium

which IMO comes back to my favorite word again in this fascinating hobby
Moderation
operating a ceiling high skimmer on a 75 gal reef tank could possibly overskim some of the good things we want in our tanks

 

[Aquarist007]

along related lines:

Phosphate starvation
Is there such a thing as phosphate starvation? Someone posted this in another thread:



quote:
--------------------------------------------------------------------------------
Yes, the zooxanthellae in coral needs some phosphate to grow, it IS an algae after all. Get a phosphate test kit and post your results. Sure high phosphate levels can do some harm to your SPS corals, however, a lack of phosphates will starve them and cause them to bleach. You may be running your water through your phosphate reactor too slowly thereby removing too much thereby causing your corals to starve.
--------------------------------------------------------------------------------



I've never heard/read of this happening, but my softies and LPS don't seem to be doing as well in the four months since I put in a reactor. I've never used more than half the recommended dosage of Phosban and all GHA melted away. My corals aren't dieing, but don't look great either. So is this a possible issue?

Thanks,
Grant

from this thread

http://www.reefcentral.com/forums/showthread.php?s=&threadid=1383158

 

[tbittner]

Here is an interesting article I found that talks about phosphates

http://www.reefs.org/library/members/r_shimek_042799.html

 

[Peter Eichler]

<a href=showthread.php?s=&postid=12470444#post12470444 target=_blank>Originally posted</a> by capn_hylinur
along related lines:

Phosphate starvation
Is there such a thing as phosphate starvation? Someone posted this in another thread:



quote:
--------------------------------------------------------------------------------
Yes, the zooxanthellae in coral needs some phosphate to grow, it IS an algae after all. Get a phosphate test kit and post your results. Sure high phosphate levels can do some harm to your SPS corals, however, a lack of phosphates will starve them and cause them to bleach. You may be running your water through your phosphate reactor too slowly thereby removing too much thereby causing your corals to starve.
--------------------------------------------------------------------------------



I've never heard/read of this happening, but my softies and LPS don't seem to be doing as well in the four months since I put in a reactor. I've never used more than half the recommended dosage of Phosban and all GHA melted away. My corals aren't dieing, but don't look great either. So is this a possible issue?

Thanks,
Grant

from this thread

http://www.reefcentral.com/forums/showthread.php?s=&threadid=1383158

Much like a protein skimmer no one really knows exactly what ferric oxide and GAC remove from our water and odds are that along with the bad "stuff" beneficial "stuff" is removed. In short, yes, it's a possible issue.

 

[toaster77]

thanks for the link on skimmate analysis - very interesting.

i believe most organisms have dedicated phosphate transporters to import phosphate from the environment. they also have phosphatase enzymes that serve to decompose macromolecules in order to scavenge inorganic phosphate. so all organisms need phosphate to proliferate and they must get it either from ingestion of food or import of free phosphate that is liberated upon decay/decomposition of food or dying matter.

so while too much phosphate is definitely bad, too little can also suppress growth. after all, DNA has a phosphate backbone, and ATP the major fuel for all cells stands for adenosine triphosphate... and this phosphate must come from somewhere. and for the symbiotic zooxanthellae (and most microorganisms)i would venture to guess that the majority of their phosphate comes from import of free phosphate in the seawater

 

[Aquarist007]

<a href=showthread.php?s=&postid=12470890#post12470890 target=_blank>Originally posted</a> by tbittner
Here is an interesting article I found that talks about phosphates

http://www.reefs.org/library/members/r_shimek_042799.html

very profound article

this misconception glared out at me:

How much live rock do you have in each of the tanks?

That is hard to say. Enough to hang the critters on... I don't think that the amount of live rock really is terribly important, I think most of the bacterial filter is in the sediment.

 

[D to the P]

It's kinda funny to think of your salt water tank as being TOO clean :hmm5:
It's as if we were given a margin for error when it comes to how well we clean our tanks. Too little and you get problems, too much and you get problems.:crazy1:
Soon phosphate test kits will have a middle range to shoot for kinda like a hydrometer

 

[adamsaranluke]

What are these "immortal" creatures that dont age and only die when they're killed? I have never heard of anything like that.

 

[adamsaranluke]

<a href=showthread.php?s=&postid=10579905#post10579905 target=_blank>Originally posted</a> by greenbean36191
And again...

14.) Inverts are short lived, so expect to replace your cleaning crew regularly.

Many popular members of cleanup crews can live decades to centuries though. Some of the animals we keep are even theoretically immortal, meaning they don't grow old. They only die when something kills them.

What kind of animals are these?

 

[Paul B]

are we to assume that nitrates and phosphates are not removed by foam fractionators and or other essential substances

Some nitrates and phosphates are removed by skimming as are bacteria and some copepods. A skimmer removes water and anything that is dosolved in it but only because in the course of removing DOC, some water is removed. But this is a trivial amount. Water changes also remove some good things. You will find everything in the skimate that is in your water. A skimmer is not 100% efficient at removing just DOC.
Carbon also removes some good substances but the removal of the bad stuff outweighs the good stuff. It is a trade off and it depends on how you have your skimmer adjusted, how large the bubbles are, the contact time, flow rate etc. etc.
Many times I accidently adjust my skimmer incorrectly because I add fish oil to my tank which stops the skimmer from making bubbles. If I try to adjust it then, in the morning I find that my skimmer removed 3 or 4 gallons of water. Am I to assume that all that removed water is DOC?
A skimmer will stop skimming when all those split molicules I mentioned are removed. There are many things a skimmer will not remove like copper, ammonia, zinc. nitrate etc. but a skimmer will remove DOC which if left in the water will become ammonia and nitrate. We as yet do not have a perfect filter that will only remove the bad stuff. The only thing that comes close is algae.
:bum: