Organic Phosphates - uptake questions

[JerseyReef]

In the "Rock Cooking" thread (which is now closed) I made a post on page 7 that I would like to expand upon and get further details from Randy and Boomer.

Here's the link of my post

http://www.reefcentral.com/forums/showthread.php?s=&postid=6640895#post6640895

Here's the link for Randy's post

http://www.reefcentral.com/forums/showthread.php?s=&postid=6641034#post6641034

Randy you were concerned with my comments on organic compounds really driving algae growth and not inorganic compounds.

Let me expand a bit and maybe give me a little latitude. First a couple of statements I'm making to make my point. Please correct and/or verify each one.

• 
  Organic and inorganic compounds are present in a closed system, either by introduction or created in the system, correct?
  
  The Organic compounds will eventually break down and form inorganic compounds (over time), correct?
  
  Organic compounds are being created in the closed system at a faster rate that inorganic compounds, giving it a higher ratio (initially).
  
  Inorganic compounds are consumed by bacteria and other microbes that uptake this compound or bound to other material and can be used by higher plant forms.

Once the Organic compounds (which is now at a higher ratio) start to break down forming inorganic compounds, at such rate that the bacteria and other microbes can not keep up with supply and higher plant/animal forms start to use the available food source. Thus, creating algae outbreaks. Skimmers are ineffceient and exporting these compounds.

First, we need to make an assumption. Organic compounds are readily available and in greater ratios than inorganic compounds in the closed system. If that is true, which would be the case with excess food added to the system and ineffective skimmer or organic compound exporting system.

Does that make the argument that organic compounds really drive unwanted algae growth, albeit indirectly?

Hence my point in having an understanding (measuring) of the organic compounds in the system, instead of the inorganic compounds?

One other question. I know the variables are many to destabilize the organic compound. Typically what are they and what impact can each variable have to destablize it?

 

[Randy Holmes-Farley]

Organic and inorganic compounds are present in a closed system, either by introduction or created in the system, correct?

Yes and Yes.

The Organic compounds will eventually break down and form inorganic compounds (over time), correct?

Most will yes. Some cannot be readily broken down, and accumulate unless bound by GAC, broken by ozone, or skimmed out.

Organic compounds are being created in the closed system at a faster rate that inorganic compounds, giving it a higher ratio (initially).

I do not know that. Do you have any data? I know ways that both are created, but not what the creation ratios might be. The ratios in existing in solution do not reflect the rates that they are created if the uptake/breakdown rates are different.

Inorganic compounds are consumed by bacteria and other microbes that uptake this compound or bound to other material and can be used by higher plant forms.

Bacteria, algae, and higher plants can take up inorganic phosphate directly. I'm not sure what you mean here. Most may not be able to take up many organic phosphate forms directly. They likely have to break them down and release the phosphate to inorganic phosphate before taking it up. That is how mammals take up phosphate from their GI tracts. Inorganic phosphate is directly taken up, but most organic forms are either not absorbed at all by mammals, or are broken down to release the inorganic phosphate that is then taken up.

First, we need to make an assumption. Organic compounds are readily available and in greater ratios than inorganic compounds in the closed system.

You can certainly make that assumption for hypothetical scenarios, but without data I do not accept it. I also do not know what you mean by readily available. Many organic compounds are not bioavailable at all. Others are poorly available, and need to be broken down before being taken up. Also, as I mentioned above, the concentration in solution does not say anything about the relative uptake of organic and inorganic forms in aquaria. If they started equally in solution, and inorganic phosphate is taken up faster, that will leave more organic phosphate in solution.


Does that make the argument that organic compounds really drive unwanted algae growth, albeit indirectly?

It does not convince me.
But this give evidence the other way:

GFO (binding inorganic phosphate, and some organic materials) is very effective at controlling green microalgae, while GAC (binding just organics) is not. So that suggest to me that the immediate cause is inorganic phosphate to a large extent. much of it may come from organic forms at some point in its history, but it is often available as inorganic phosphate before taken up by algae.

One other question. I know the variables are many to destabilize the organic compound. Typically what are they and what impact can each variable have to destablize it?

Organics are typically broken down by enzymes, and ozone if it is being used. The enzymes may be inside of organisms, on their surface, or to a smaller extent, out in solution. Large organic molecules are broken apart into smaller ones, that are more readily taken up, through the action of enzymes in solution or on organism surfaces.

 

[JerseyReef]

Great response! Let's expand on this point a bit...

<a href=showthread.php?s=&postid=6775920#post6775920 target=_blank>Originally posted</a> by Randy Holmes-Farley
Organic compounds are being created in the closed system at a faster rate that inorganic compounds, giving it a higher ratio (initially).

I do not know that. Do you have any data? I know ways that both are created, but not what the creation ratios might be. The ratios in existing in solution do not reflect the rates that they are created if the uptake/breakdown rates are different.

The primary source of organic compounds is the introduction of food items into the closed system, correct?

Since the organic compound is not easily used and if the organic compound is not exported (no skimming), build up can continue to occur until the ratio is higher than the inorganic compound, since organic compounds are not easily broken down or used, correct?

With zero or ineffective exporting functions in the closed system, the creation of organic compounds (continued introduction of food source) would eventually out pace the uptake and breakdown (organic compounds broken down to inorganic compounds for uptake) of the inorganic compounds in the closed system, correct?
- this assumes that ozone is not used to break down the organic compounds to inorganic compounds

At some point, the organic compounds will have to be broken down to inorganic compounds to be taken up, as you mentioned in your last post. However, those variables are too many.

Maybe my point is too hypothetical to make the connection I'm looking for. I think we would want a better understanding of the organic compounds in the closed system, especially if the ratio to the inorganic compounds are higher in the system.

I do remember a point you raised in the Sep 2002 AA issue

In your Sept 2002 article you mention algae outbreaks that can be caused primarily by organic compounds (I believe you were referencing GFO methods). Can my hypothetical scenario be a catalyst for algae outbreaks (fueled/driven by organic compounds)?

 

[Randy Holmes-Farley]

The primary source of organic compounds is the introduction of food items into the closed system, correct?


Well, perhaps not. A lot of organics come from dead bacteria, algae, etc, and secretions/excretions from all the organisms in the tank. Food is certainly the primary external source, however.

Since the organic compound is not easily used and if the organic compound is not exported (no skimming), build up can continue to occur until the ratio is higher than the inorganic compound, since organic compounds are not easily broken down or used, correct?

That is certainly possible, yes. Is it ever or always true in a reef aquarium? I do not know. But I would not be at all surprised if DOP (dissolved organic phosphate) is higher then DIP (dissolved inorganic phosphate).

With zero or ineffective exporting functions in the closed system

Well, that depends on what you mean by exporting. Bacteria and algae certainly take up nutrients of many kinds. If you export them, you can export the nutrients. I agree that with no export of any kind, nutrients including phosphorus will build up in some form in the tank.

the creation of organic compounds (continued introduction of food source) would eventually out pace the uptake and breakdown (organic compounds broken down to inorganic compounds for uptake) of the inorganic compounds in the closed system, correct?

I'm not sure that I understand what you are saying. But certainlyif one measures a rise in DOP or DIP,it is outpacing reduction of those things. If DIP and DOP are steady, then the use of them it is balancing the input/formation of them.

At some point, the organic compounds will have to be broken down to inorganic compounds to be taken up, as you mentioned in your last post. However, those variables are too many.

Too many for what? To understand them all? Yes. Too many for it to be inportant? No.

I think we would want a better understanding of the organic compounds in the closed system

I absolutely agree with that. The firstl line of this article:

Organic Compounds in the Reef Aquarium
http://reefkeeping.com/issues/2004-10/rhf/index.htm

is
"Organic materials represent what is likely the least understood area of chemistry in reef aquaria. "

 

[Randy Holmes-Farley]

In your Sept 2002 article you mention algae outbreaks that can be caused primarily by organic compounds (I believe you were referencing GFO methods). Can my hypothetical scenario be a catalyst for algae outbreaks (fueled/driven by organic compounds)?

You mean this quote?

"An important point about organic phosphates is that they will mostly not be impacted by phosphate-binding materials sold to the aquarium hobby. Consequently, while these products may do a fine job of reducing inorganic orthophosphate, they may not help an algae problem that is caused primarily by organic phosphates."

That doesn't imply that all or most algae problems are caused by organic phosphates, only that if organic P is what is driving algae, that the binders may not help. Experience seems to show that binders do help, however, now that GFO use has become popular enough to see a lot of experiences with it.

 

[JerseyReef]

<a href=showthread.php?s=&postid=6776728#post6776728 target=_blank>Originally posted</a> by Randy Holmes-Farley
You mean this quote?

"An important point about organic phosphates is that they will mostly not be impacted by phosphate-binding materials sold to the aquarium hobby. Consequently, while these products may do a fine job of reducing inorganic orthophosphate, they may not help an algae problem that is caused primarily by organic phosphates."

That doesn't imply that all or most algae problems are caused by organic phosphates, only that if organic P is what is driving algae, that the binders may not help. Experience seems to show that binders do help, however, now that GFO use has become popular enough to see a lot of experiences with it.

Randy - thanks for the previous responses. Question about the above comment. How can the aquarist determine if organic compounds is driving the algae issue or if driven by the inorganic compounds? If testing is not possible, without creating a science lab.?

 

[Randy Holmes-Farley]

I do not know of any way to tell which is driving algae without looking very closely at the biological uptake mechanisms. It isn't a home project.

One could show that inorganic phosphate COULD be driving it by adding inorganic phosphate and seeing if it worked in a system where there was no chance that bacteria could be converting it into organic forms before the algae got it. The reverse experiment would not be definitive as the organic forms might be broken down before being taken up, and it is not apparent what chemical to actually test.

FWIW, it isn't even known with certainty how inorganic phosphate is taken up in the human GI tract, so it is not surprising that such info is not totally clear for marine organisms.