The great debate on nitrates and phosphates

[Elegance Coral]

Thank you very much.

It seems it is about the definition of what is " digestion". About an animal " digesting " food and absorbs it. In this work intercellular absorbtion of already degradated symbiodinium is called " digestion" by the researchers.
The researches also observed "digestion" of apparently healthy zooxanthellae. I did not read all already but it seems it is not clear if the degradation is caused by the coral to feed itself . it seems the symbiodinium has degradated because of external conditions nothing to do with the coral. In 1996 not many was known about the coral holobiont.
I do not know if any enzymes are produced and used by the host with the intension to "digest" symbodinium, if the coral has the intension to feed on the symbodimium, use it as a foodsource and produces the enzymes to "digest" it. In what conditions the enzymes are activated as in the case the coral may grow on the "digestion" of symbiodinium.

Sorry about the misunderstanding about " digestion" and thank you again for the link.

No problem at all. I hope you find the time to read the whole thing. It is a good informative read.

On the question of whether or not these corals are degrading/digesting their zooxanthellae to feed themselves, I believe this quote from the link answers it.
" the polyps regulate the intensity of algal degradation which is stimulated by a deflciency of food, and degradation is rapidly terminated upon reintroduction of food."

Peace
EC

 

[Elegance Coral]

Well I did feed a lot and I target feed the corals 6 month didn’t see any changes other then my corals bleaching ..and only in one week of adding nitrate and lowering my alkalinity did the trick ..now after one week all my corals look open fatter colorful and grow I even dose energy from Red Sea a&b and nothing...

So, you reduced the alk, which lowers the growth rate, which in turn, reduces the nutritional requirements of the coral, then added a fertilizer like nitrate to stimulate zooxanthellae reproduction, and your corals appeared to improve. I have no problem with that. Sounds logical enough to me. Perhaps, if you would have lowered alk, while feeding the same amount, you may have seen the same, or similar results. Without the addition of nitrate.
Maybe, if the coral fed more, you could have kept the alk level up, without compromising growth, and without the addition of nitrate, and still seen a similar result with fatter, more colorful, and growing corals.

and as far as Ik zooxanhellae is a type of algae and algae eat nitrate and phosphate

Yes. Zooxanthellae do require nitrogen and phosphorus. Like I said in my post, that does not mean they need N and P in the open water of the system. When the coral host feeds, it produces inorganic N and P as a waste produce. The zooxanthellae can obtain their required N and P from right inside the coral, where it is produced. Regardless of the N and P concentration in the surrounding water.

Peace
EC

 

[Elegance Coral]

Recent research of many different sources has shown that increased availability of phosphorus does increase calcification which is in contradiction with what is believed by most reefers and most guidelines.

Can you provide a link to substantiate this claim?

I'm aware of only one, very flawed, research paper that suggests what you're saying is true. It came out quite a few years ago, so I don't remember all the details, but I did read the whole thing.

Basically, they took multiple frags, placed them in individual containers, exposed them to different PO4 levels. and observed them over time. No where in that research paper, did they mention organic food of any kind. So, what they had was starving corals. What they showed is that increasing PO4 levels can increase growth rates over and above the growth rate of a coral that's starving. All life requires phosphorus to grow. Naturally, if there is little P, there would be little grow. Which they showed. Adding a source of P in such a situation can increase growth. Which they showed. What they did not show, is how PO4 effects healthy, well nourished corals. It is possible that elevated PO4 can inhibit calcification/growth in healthy corals that are not starved for P. Which field research has shown.

That research paper was very misleading. To get a true understanding of how PO4 effects coral growth and calcification, first we would need to start with corals that are healthy and have adequate nutrition. Then manipulate the PO4 levels and document the results. All they did is show that increasing PO4 in the water around a starving coral can increase growth/calcification. Countless hobbyists have witnessed this for themselves after running an ULNS, then increasing PO4 levels, and seeing an increase in growth.
A particular coral would require X amount of PO4 to support X amount of growth. What happens when a coral already has X, and then we elevate the PO4 levels beyond that??? Could calcification become more inhibited the higher we go above X????
Their research concentrated on corals that were not receiving X, so naturally, the more they raised PO4, and the closer they got to X, the higher the growth rate became. They only showed what happens when phosphorus is limiting. Most scientists could have theorized exactly what they showed without the research ever being done. The question is, what happens when phosphorus is no longer limiting, and we keep increasing the level???

Peace
EC

 

[Belgian Anthias]

No problem at all. I hope you find the time to read the whole thing. It is a good informative read.

On the question of whether or not these corals are degrading/digesting their zooxanthellae to feed themselves, I believe this quote from the link answers it.
" the polyps regulate the intensity of algal degradation which is stimulated by a deflciency of food, and degradation is rapidly terminated upon reintroduction of food."

Peace
EC

The symbiosis between coral and symbiodinium is mutual, which means they both profit. During temporary nutrient limited conditions the coral will provide the essentials for the symbiodinium . The symbiodinium will provide essentials for the coral for growing. When the symbiodinium degrades we speak about starvation and dead . This means something happens which had nothing to do with the symbiosis. The coral has nothing to do with it. The coral does not "feed " on the symbiodinium. When degraded organic matter is absorbed by cells this is just what they do all the time. Till now I could not find any proof corrals actually "feed" on and "digest" active symbiodinium.
A lot of "difficult" corals are not able to construct all essential amino-acids and they need species related symbiodinium to provide the enzymes to construct that essential amino-acid missing . Hundreds different species and clades of symbiodinium may be present but missing the ones needed will be fatal. That makes them "difficult" as during transport corals may lose most of there symbiodinium, including the most essential species related ones. The coral will not be able to grow!
Recent research of the coral holobiont has availability about other and better options for "observation"
Will a coral " digest" and actualy feed on its live symbiodinium? As it does by taking up other organics filtered from the water. I do not know (yet).

 

[Belgian Anthias]

Can you provide a link to substantiate this claim?
The question is, what happens when phosphorus is no longer limiting, and we keep increasing the level???

Peace
EC

The study is based on the following data: We found 26 studies with 101 separate experiments of 17 types of coral that met all of our criteria for analyzing nutrient loading on coral growth. Studies that reported the change in mass per unit volume of whole colonies over time were used in our analysis as measurements of both calcification rates and skeletal density. As a result, we were able to obtain 59 independent measurements of calcification from 21 studies, 37 measurements of skeletal growth rates from 14 studies and 19 measurements of skeletal density from 5 studies. To assess the impact of nutrient enrichment on Symbiodinium and photosynthesis, we identified 21 studies with 107 separate experiments of 13 species of corals. We found 27 experiments from 8 studies that assessed how the nutrient input changes the chlorophyll density within Symbiodinium, 38 experiments from 15 studies on the density of Symbiodinium, 27 experiments from 11 studies that investigate chlorophyll per density of coral surfaces, and 15 experiments from 6 studies investigating the gross photo-synthetic capacity of corals

Calcification is partly determined by the N: P ratio but the nitrogen source also appears to be important. A large difference was noted when ammonium or nitrate was used as the nitrogen source.
Nitrate caused a significant reduction in calcification, while there was no effect of ammonium. Nitrate also caused a significant increase in chlorophyll A density within Symbiodinium, but again ammonium had no effect. In contrast, only ammonium caused a significant increase in the density of Symbiodinium in the coral tissue, while nitrate had a trending positive but unimportant effect.

One must be aware that it is about the nitrogen source used. Not about availability in the water column. Most organisms grow a lot slower when using nitrate-nitrogen as a nitrogen source, not only corals. it is a normal condition as organisms must spent a lot more energy for using nitrate as a nitrogen source.
Slower growth means higher density.

Individual studies suggest complex, even contradictory, relationships between nutrient availability, coral physiology and coral growth. Here they used meta-analysis to determine general patterns of the influence of nitrogen (N) and phosphorus (P) on coral growth and photobiology. In general, they found that N over a wide range of concentrations reduced coral calcification by an average of 11%, but improved aspects of coral photobiology, such as the rate of photosynthesis. In contrast, P-enrichment increased the average calcification rate by 9%, probably due to direct effects on the calcification process, but had minimal effect on coral photobiology

This is less as expected as most organisms slow down there metabolism x2 x4 even x8 when using nitrate as a nitrogen source.

Rather than suppressing growth as generally believed, P-enrichment improves calcification in corals, but may deteriorate skeletal firmness.

In aquaria corals have the intention to grow towards the light and the light intensity difference between the base and the top is different from nature which means growth in captivity is difficult to compare with natural growth. Very important for light adapted species and shade adapted species. This makes shade adapted species ( with branches) more difficult to keep in captivity.

The nitrogen source used depends of the composition of the holobiont . The availability of nitrogen in the holobiont will be completely different of what is measured in the water column. The same for phosphorus availability.
If the environment changes the composition of the holobiont will change consuming more ore less nutrients , producing or and consuming buiding materials. hetertrophs, autotrops, vast growers, slow growers, taking up nutrients fast limiting availability in the micro environment, slower growing using other nitrogen sources, retrieving nitrogen by fixation when the nitrogen supply is insufficient to maintain the holobiont. They live in a micro-world which is influenced by the surrounding water.
One may be surrounded by a lot of food but if around you the others consume it faster or are so many nothing may reach you, you will starve. if they like you maybe they will share it with you, if they like you very much maybe they bring it to you. It is about what happens in the micro environment what determines the availability of building materials. That is why denitrification takes place in a nitrifying biofilm when measuring normal DO levels in the aquarium.

it is all about diversity and competition, about live, not about preventing it.

The parameter influencing calcification most is the availability of CO3.

The calcification rate is of no importance for a reef aquarium as long calcification takes place at a positive rate.

Other essential building materials may and will limit growth in the micro environment where it all happens, certainly in a LNS in which a skimmer removes some of the organics constantly but very selective .


The above information is a translation of parts of the original article written in Dutch by CMF De Haes and references are available in the article . ( References in English which are consult able) Available for reading In our wiki Makazi Baharini, our knowledge base. ref: baharini.eu/baharini/doku.php?id=nl:makazi:chemie:calcificatie

I can not add an active link to our wiki or the article as R2R considers it as a commercial website because the wiki contains a donation button. One must register to read most articles of which a lot are translated in English . Registration is for free. The wiki is read only for registered readers and the information may be used for personal use only.The wiki does not contain any commercial influenced information and only articles based on approved research information which can be consulted. The wiki Makazi Baharini is intended to be a knowledge base about keeping and managing marine live support systems.

 

[Cheche]

So, you reduced the alk, which lowers the growth rate, which in turn, reduces the nutritional requirements of the coral, then added a fertilizer like nitrate to stimulate zooxanthellae reproduction, and your corals appeared to improve. I have no problem with that. Sounds logical enough to me. Perhaps, if you would have lowered alk, while feeding the same amount, you may have seen the same, or similar results. Without the addition of nitrate.
Maybe, if the coral fed more, you could have kept the alk level up, without compromising growth, and without the addition of nitrate, and still seen a similar result with fatter, more colorful, and growing corals.



Yes. Zooxanthellae do require nitrogen and phosphorus. Like I said in my post, that does not mean they need N and P in the open water of the system. When the coral host feeds, it produces inorganic N and P as a waste produce. The zooxanthellae can obtain their required N and P from right inside the coral, where it is produced. Regardless of the N and P concentration in the surrounding water.

Peace
EC

this is the thing . I was obligated to lower the alk do to the fact the I OD the fertilizer to over 100 ppm and had to do 10g wc every 5 hours to lower the nitrate to 10ppm. No bcoz I want to slow rate but no nutrients higher alk don’t work. So do to the constant wc the alk was dropping slowly as my nitrate was dropping too .. I did noticed all my corals improvement though the days.and the fact the I wait 6 months feedings heavy and actually see no changes or actually getting worse and adding nitrate as alk drop fix all my pale and bleaching problems was the key to make me believe corals need nitrate to look healthy this is not about alk this is about nitrate and phosphate.. and the part about the zooxanthealle we are in same page. They do need n&p but if the coral gets the n&p from the water and the zoo gets it from the coral still the same subject zoox need nitrate and phosphate to reproduce and give enough protection to the coral to look better and healthier.. my system have the same problem old school reef keeper have .. we keep our water toooo clean and now the more scientific facts we can google and get a better understanding the coral need some dirty water too to look good ..

 

[aquatic engineer]

I'm reading this with interest as I am about 9 months into my first tank and currently have zero nitrates and phosphates and have had this almost from the beginning. However, in the beginning, I had a lot of GHA, which I slowly have replaced (mostly) with ulva in both the refugium and the DT. The growth in the DT is enough to feed my 3.5 inch purple tang, 2 inch hippo tang, and a blenny. I am waiting on an order to get a scribbled rabbitfish as my final herbivore. Based on where I'm at now, I think the rabbitfish will bring the DT into balance in terms of algae growth versus fish feeding.

Having said that, I'm still growing my corals from frags. I only have one larger plating montipora (~3 inches square) and a toadstool pair of about 2 inches each. All others are frags or at or less than 2X the original frag size. Thus, their demand isn't very heavy yet for nutrients.

I'm not crazy about all the ulva in the DT, but it's better than GHA or worse things. So, my question to those more seasoned reefers is whether my system sounds healthy, despite the zero free nitrates and phosphates? Or am I heading for a problem as my corals grow or other parts of the biome mature?

 

[Belgian Anthias]

For those who are staring blindly at the phosphate level and pursue the natural phosphate content .
It has been found that in nature the inorganic phosphate concentration present in coral mucus is approximately 135 times the concentration in surrounding water. High DIP concentration in coral mucus may enhance heterotrophic bacterial production and associated carbon flow in the microbial loop of the coral holobiont.
This way Corals may be able to control the availability of usable carbon within the holobiont this way controlling fast growth and the availability of nutrients in the coral holobiont. In nature the phosphate concentration in surrounding waters is very low but the supply is unlimited.

 

[Elegance Coral]

I'm reading this with interest as I am about 9 months into my first tank and currently have zero nitrates and phosphates and have had this almost from the beginning. However, in the beginning, I had a lot of GHA, which I slowly have replaced (mostly) with ulva in both the refugium and the DT. The growth in the DT is enough to feed my 3.5 inch purple tang, 2 inch hippo tang, and a blenny. I am waiting on an order to get a scribbled rabbitfish as my final herbivore. Based on where I'm at now, I think the rabbitfish will bring the DT into balance in terms of algae growth versus fish feeding.

Having said that, I'm still growing my corals from frags. I only have one larger plating montipora (~3 inches square) and a toadstool pair of about 2 inches each. All others are frags or at or less than 2X the original frag size. Thus, their demand isn't very heavy yet for nutrients.

I'm not crazy about all the ulva in the DT, but it's better than GHA or worse things. So, my question to those more seasoned reefers is whether my system sounds healthy, despite the zero free nitrates and phosphates? Or am I heading for a problem as my corals grow or other parts of the biome mature?

This is what I was talking about in my first post, #30, on page 2.

Your system clearly shows that organisms can obtain plenty of nitrogen and phosphorus to support growth even when test kits read zero.

The zero reading for nitrate and phosphate can be misleading for many hobbyists. For what you're talking about, those readings are all but meaningless. Mother nature is telling you far more about the conditions within the system than the test kits are.

We know, for a fact, that we can not grow "a lot of GHA" without a lot of inorganic nitrogen and phosphorus to support that growth. Period. If algae has access to it, so does everybody else in the system. Including our corals.

I assume you're not adding nitrate or phosphate directly, and your test kits show that it's not building up in the water, so where is the algae getting all this inorganic nitrogen and phosphorus from? Well, your system has to be producing it. Organics, the foods you feed, are remaining in the system long enough to break down/rot/decompose and release inorganics. This is obviously true even if the test kits can't detect this process.

Algae growth isn't the problem. It's the symptom of the problem. The problem is the production of inorganics like inorganic nitrogen and phosphorus within the system. Reduce the production of inorganics, and you reduce the growth of algae. Even if the test kits are reading zero.

Using herbivorous to combat the symptoms, does not treat the problem, and can actually cause the problem to get worse over time. Herbivorous consume the organic algae, then directly release inorganics back into the water, fueling more algae growth. They also produce organic fecal material that can break down, releasing more inorganics, and fuel more algae growth. This process can trap and hold nutrients within the system where they are cycled from organic to inorganic, and back to organic, many many times. All while we add more organics every day, and the nutrient level of the system as a whole can continue to rise. All while our test kits read zero.

Even if we add enough herbivorous to completely mow down all the algae in the system, we essentially reduce the systems ability to convert inorganics like nitrogen and phosphorous, into organics, and inorganics can accumulate in the system, causing the numbers on test kits to rise, as algae cover decreases.

Reducing the amount of inorganics the system produces, breaks these cycles, and starves algae of it fertilizer. One very effective way to accomplish this is to limit the time that organic particles remain within the system. Preventing them from breaking down and releasing inorganics into the system.

Methods to accomplish this......
1. Adequate flow within the system to keep organic particles suspended so filtration can remove them before they rot.
2. Run mechanical filtration, like socks, that are changed out fast enough to keep the small particles of organic matter they trap from rotting within the system.
3. Reduce particle traps within the system. LR and sand are particle traps. They're areas where organic particles can build up, rot, and become little more than compost piles producing fertilizer.
4. Run a properly sized skimmer.
5. Change water, with an emphasis on removing organics trapped in sand, rock, and anywhere else in the system.
6. Remove any unwanted organisms that play a part in the cycling of nutrients within the system. Like algae, and worms.

HTH
Peace
EC

 

[ajm83]

ULNS= dead SPS for me

Fast forward 6 months. No3 is 35 and Po4 is .1
SPS is encrusting like mad and colors are great.

Same here, but the problem I have is that at numbers like that, my tank needs constant work to remain algae free. Not the rockwork, but things like the powerheads where CUC can't get to. Also the glass needs scraping every two days and if you don't, whatever algae it is really cements itself on there! I had to use a razor to remove it after a short holiday - my Tunze Care wouldn't touch it!