Sixty’s Understanding of Nutrient Ratios

Randy Holmes-Farley

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Am not debating, am just stating that P is only a limiting factor to the other nutrients wend its zero, I’ve included GFO a few comments back, it’s a alternative to the increase of the nutrient C and N doing the same job. GFO it’s a standard procedure in reefing and the formula accounts for that.

In a published study using normal seawater containing 0.012 ppm N (partly ammonia and partly nitrate) and 0.012 ppm phosphate, one species of macroalgae was phosphate limited for growth, and eight species were N limited. These limiting factors were evaluated by dosing them and observing what effects enrichment had.

I do not see how ratios or equations would have predicted this experimental observation.
 
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sixty_reefer

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In a published study using normal seawater containing 0.012 ppm N (partly ammonia and partly nitrate) and 0.012 ppm phosphate, one species of macroalgae was phosphate limited for growth, and eight species were N limited. These limiting factors were evaluated by dosing them and observing what effects enrichment had.

I do not see how ratios or equations would have predicted this experimental observation.
We are back in full circle, We back at discussing availability of nutrients that is different from residual nutrients, all those species in their natural habitat are not limited as there is a unlimited amount of nutrients available, wend put in a box without anything being added they will deplete the residual nutrients in different ways, some will require more N and one as found will need more P. That only shows me that one of those nine species has a high requirement in phosphates.
It doesn’t mean that that particular species is causing our oceans to have less phosphates. It’s just a study to try and quantify the needs of N and P of Nine specie of algaes.


the ratios and equation would only bring more questions instead of answers to this study as NSW was used and could influence final results.

1. Was Doc and N-Doc in the samples tested or taken into account
2. Was any die off in the algaes observed during the period of the test
3. Was the water filtered to remove zooplankton
4. Was bacteria present in the samples

just a few questions that could influence the overall results, this may be one of the reasons most published studies never finish with a statement but a probability.

were the formula would be useful would be in the place were the NSW samples were collected from, as the Nitrates and phosphates are known, if those values were to change at a later date, it could help identify what’s causing the changes in that particular ecosystem.
 
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Randy Holmes-Farley

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I do not see any reason to continue this debate, and this is my last post.

The study definitively stated which macroalgae in the ocean under those conditions were N or P limited.

None of the things you ask for are useful to know whether macroalgae in that water were limited by N or P. Only experiments can tell the answer, and only by boosting one or both can you tell whether one of them is limiting to any particular species.

if you believe you’ve discovered a different way to tell what limits organism growth, I’m not understanding it.
 
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I do not see any reason to continue this debate, and this is my last post.

The study definitively stated which macroalgae in the ocean under those conditions were N or P limited.

None of the things you ask for are useful to know whether macroalgae in that water were limited by N or P. Only experiments can tell the answer, and only by boosting one or both can you tell whether one of them is limiting to any particular species.

if you believe you’ve discovered a different way to tell what limits organism growth, I’m not understanding it.
I was thinking the same we starting to go in circles, I really appreciate your help on the discussion as you helped me immensely to understand the formula, maybe we should pick it back up in future wend I acquire enough knowledge to explain it in a more scientific way.
 
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sixty_reefer

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This will be my last post on this topic too, but only because I no longer wish to see OP misuse the word 'wend' any longer.

I'm out!
Sorry, didn’t even notice wend you posted :)
 
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This is some more substantial evidence


The formula already exists and it’s nothing new apparently. That’s from ati and the chart is similar to what we have been discussing. They also know where the ratio is.
 

homer1475

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This will be my last post on this topic too, but only because I no longer wish to see OP misuse the word 'wend' any longer.

I'm out!
My thoughts exactly since I started reading his posts weeks ago. I just don't like to be the grammar police, simply because I know I misuse words all the time.
 
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My thoughts exactly since I started reading his posts weeks ago. I just don't like to be the grammar police, simply because I know I misuse words all the time.
English is not my maiden language, I will commit serious grammar mistakes eventually :p
 

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English is not my maiden language, I will commit serious grammar mistakes eventually :p
Ecological Stoichiometry by Sterner and Elser might be a useful book for understanding element ratios, what they are and how scientists use them to understand ecology. The first few chapters might be all you need or want to read.

Element ratios seem to have explanatory power when you compare what is consumed versus what becomes incorporated into the biomass in the context of a growth rate. Moreover, these element ratios need to be referenced to carbon if the measured N and P values are are to be put into context of growth. What we aquarists try to do with element ratios is to observe an element ratio in water and speculate what it means with reference to thousands of species without any knowledge of growth rate biomass element ratio of those species, or with reference to carbon. Some might call that wild speculation or wishful thinking :)

Take a look at that book and see if you can advance your idea even further.

Dan
 
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Ecological Stoichiometry by Sterner and Elser might be a useful book for understanding element ratios, what they are and how scientists use them to understand ecology. The first few chapters might be all you need or want to read.

Element ratios seem to have explanatory power when you compare what is consumed versus what becomes incorporated into the biomass in the context of a growth rate. Moreover, these element ratios need to be referenced to carbon if the measured N and P values are are to be put into context of growth. What we aquarists try to do with element ratios is to observe an element ratio in water and speculate what it means with reference to thousands of species without any knowledge of growth rate biomass element ratio of those species, or with reference to carbon. Some might call that wild speculation or wishful thinking :)

Take a look at that book and see if you can advance your idea even further.

Dan
Thank you Dan, I do not wish to be looking in advancing the theory, I believe I understand it and I’ve tried to discuss it. It’s up to each one to make there own beliefs, I will read the book you recommend to satisfy my curiosity.
 
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sixty_reefer

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I am having quite a lot of notifications from this thread in the past few weeks, I have now consolidated all the main information regarding nutrient limitations in this thread it may be less confusing that scrolling trough such a large thread.

https://www.reef2reef.com/threads/sixty’s-understanding-of-nutrients-2-0.916975/

you may have to copy the link into the browser
 

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I think the question by now should be:

If redfield and ratios are so useless for the hobby, why can I answer so many questions on nutrient limitation using only redfield and no3 and po4 shifts.

Surely this must be known to oceanographers and other scientists that work in the field. I can’t be the first doing the connection really.
I don't now whether this has been discussed before here but - to this post specifically:

1. No one knows (no offense) whether the answers to the questions are 'correct'.
2. The Redfield ratio IMHO - is a misused 'theory' - in that it was not designed to be used in aquariums - and additionally we can't measure N and P in our tanks. BUT - lets pretend the Appropriate N:p ratio is 16:1. Of course - we don't measure N and P - but for the sake of this comment it doesnt matter - lets say your nitrate is 160 - and PO4 10. Thats a ratio o 16:1. So would be a nitrate of 1.6 and a PO4 of .1. Which set of parameters would be best? The ratio is the same?
3. The Redfield ratio was a measure of C, N, and P in phytoplankton - as compared to C N and P in 'water'. This paper, describes the differences - and may help the discussion:

A non-scientific article which is well referenced - and tries to explains the issues with ratios: https://reefs.com/forum/advanced-reefs/284211-redfield-ratio-revisited-what-we-doing-wrong-1.html
 
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I don't now whether this has been discussed before here but - to this post specifically:

1. No one knows (no offense) whether the answers to the questions are 'correct'.
2. The Redfield ratio IMHO - is a misused 'theory' - in that it was not designed to be used in aquariums - and additionally we can't measure N and P in our tanks. BUT - lets pretend the Appropriate N:p ratio is 16:1. Of course - we don't measure N and P - but for the sake of this comment it doesnt matter - lets say your nitrate is 160 - and PO4 10. Thats a ratio o 16:1. So would be a nitrate of 1.6 and a PO4 of .1. Which set of parameters would be best? The ratio is the same?
3. The Redfield ratio was a measure of C, N, and P in phytoplankton - as compared to C N and P in 'water'. This paper, describes the differences - and may help the discussion:

A non-scientific article which is well referenced - and tries to explains the issues with ratios: https://reefs.com/forum/advanced-reefs/284211-redfield-ratio-revisited-what-we-doing-wrong-1.html
I refer in this thread that our aquariums ratio is closed to redfield, not necessarily the same in page 9 and 10 I done a few charts to illustrate we’re the ratios can be seen, they are in the availability of nutrients and not in the residual nitrates and phosphates. The ratio is one of them things that can’t be increased although it can become limited. the ratio is what some would describe as carbon cycle or nitrogen cycle in sea water, those cycles are set mainly by bacteria and other organisms may do slight interfere.
 

MnFish1

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I refer in this thread that our aquariums ratio is closed to redfield, not necessarily the same in page 9 and 10 I done a few charts to illustrate we’re the ratios can be seen, they are in the availability of nutrients and not in the residual nitrates and phosphates. The ratio is one of them things that can’t be increased although it can become limited. the ratio is what some would describe as carbon cycle or nitrogen cycle in sea water, those cycles are set mainly by bacteria and other organisms may do slight interfere.
So - if you would do me a favor - what was your conclusion. Mine is the Redfield ratio is meaningless in a reef tank setting
 
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I refer in this thread that our aquariums ratio is closed to redfield, not necessarily the same in page 9 and 10 I done a few charts to illustrate we’re the ratios can be seen, they are in the availability of nutrients and not in the residual nitrates and phosphates. The ratio is one of them things that can’t be increased although it can become limited. the ratio is what some would describe as carbon cycle or nitrogen cycle in sea water, those cycles are set mainly by bacteria and other organisms may do slight interfere.
Except I will point you to this: The Redfield ratio does not refer to concentrations of CNP in the water - but rather the concentrations in phytoplankton. To my understanding - despite reading multiple articles - the CNP in the organisms affects the amounts in the water - as compared to the reverse - it becomes a meaningless issue - IMHO - sorry to say
 
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So - if you would do me a favor - what was your conclusion. Mine is the Redfield ratio is meaningless in a reef tank setting
My conclusion is that molar ratios can be helpful to understand nutrient limitations and behaviour in more depth, a limitation in the nutrients is how we lose stability in aquaria, a limitation in the nutrients is what causes Cyanobacteria, dinoflagellates and algae blooms. There is much that we can learn and move the hobby forward if understood correctly.
we can’t use molar ratios to set a residual phosphates or nitrates they just to be used as indications of what’s not been utilised by the organisms in a tank. This is the reason they’re absolute value is no longer important in the hobby and every one has similar results using different residual values.
 
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Except I will point you to this: The Redfield ratio does not refer to concentrations of CNP in the water - but rather the concentrations in phytoplankton. To my understanding - despite reading multiple articles - the CNP in the organisms affects the amounts in the water - as compared to the reverse - it becomes a meaningless issue - IMHO - sorry to say
Do you follow lass build thread? He done extensive testing and he actually tested for organic carbon, nitrogen and phosphorus content in his tank, the chart it’s not much different for the availability of nutrients. I understand your views I used to have similar views until all the pieces started to make sense. I never understood what caused Cyanobacteria in all my years in the hobby once this clicked in I see it in a different way now.
 

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Do you follow lass build thread? He done extensive testing and he actually tested for organic carbon, nitrogen and phosphorus content in his tank, the chart it’s not much different for the availability of nutrients. I understand your views I used to have similar views until all the pieces started to make sense. I never understood what caused Cyanobacteria in all my years in the hobby once this clicked in I see it in a different way now.
Yes - thats why I asked @Lasse to comment
 

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My conclusion is that molar ratios can be helpful to understand nutrient limitations and behaviour in more depth, a limitation in the nutrients is how we lose stability in aquaria, a limitation in the nutrients is what causes Cyanobacteria, dinoflagellates and algae blooms. There is much that we can learn and move the hobby forward if understood correctly.
we can’t use molar ratios to set a residual phosphates or nitrates they just to be used as indications of what’s not been utilised by the organisms in a tank. This is the reason they’re absolute value is no longer important in the hobby and every one has similar results using different residual values.
Here is a question.. Lets say I have a tank full of cyanobacteria - and treat it with chemiclean. - what will happen
 
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