Why your aquarium needs nitrates (no3)?

[sixty_reefer]

This is excellent, imo, and similar to my own idea of nuisance algae including dinos. I have never seen a problem with dinos as a single nuisance

Yes, and thinking about it, I can’t recall seeing it happen often in mature aquariums either even in systems with undetectable nitrate and phosphate.

Which brings me back to the insurance question.

At what point do our aquariums stop needing dinoflagellate insurance?

 

[RoanokeReef]

Yes, and thinking about it, I can’t recall seeing it happen often in mature aquariums either even in systems with undetectable nitrate and phosphate.

Which brings me back to the insurance question.

At what point do our aquariums stop needing dinoflagellate insurance?

The problem I see with Dinos is most everyone seems to think anything brown is Dinos without using a microscope to confirm they have Dinos.

To the topic at hand, I usually have 0 Nitrates and when I do dose to get them to 10ish I almost always get an algae breakout, so I live with 0.

 

[Dan_P]

dinoflagellates themselves are not generally considered mat forming or biofilm forming organisms?

i don’t know who you are referring to as the ones “not generally considering” dinoflagellates being mat formers. Dinoflagellates are known to be both or either if you know anything about dinoflagellates.

 

[CHSUB]

i don’t know who you are referring to as the ones “not generally considering” dinoflagellates being mat formers. Dinoflagellates are known to be both or either if you know anything about dinoflagellates.

I would agree, however imo it is more common for mats to be associated with Cyanobacteria. When I see “mats” on-line in problem algae post, I believe it is a combination of nuisance algae. Here is a picture from Sprung in his algae book of a “mat” of dinoflagellate.

 

[Tripod1404]

Nitrate is the storable form of nitrogen for vast majority of photosynthetic organisms. When nitrogen is excess, they convert it to nitrate and store it in the vacuole for future use.

In land plants, concentration of nitrate in the vacuole can be be as high as ~100 mM, which would be around 5000-6000 PPM.

So having some nitrate is water is a good insurance for not depleting nitrate stocks of photosynthetic organisms.

Oddly dinoflagellates are one group that generally do not store much nitrate in their vacuole. So perhaps that is the reason why they become dominant in low nitrate conditions since they are better adapted to low nitrate compared to other algae.

 

[CHSUB]

At what point do our aquariums stop needing dinoflagellate insurance?

I don’t believe we need insurance at all for anything, including dinos. “Insurance” is a term I borrowed from RHF that adequately describes what dosing no3 accomplishes in low nutrient situations. Some may believe no3 is a cure for something, I don’t.

 

[CHSUB]

Nitrate is the storable form of nitrogen for vast majority of photosynthetic organisms. When nitrogen is excess, they convert it to nitrate and store it in the vacuole for future use.

In land plants, concentration of nitrate in the vacuole can be be as high as ~100 mM, which would be around 5000-6000 PPM.

So having some nitrate is water is a good insurance for not depleting nitrate stocks of photosynthetic organisms.

That makes a lot of sense, however that is not how it works in ocean reef. Nitrates is nearly nonexistent in the oceans and even zooxanthella, a photosynthetic organisms, have adapted strategies to capture organic nitrogen.

https://www.academia.edu/105420762/...l_strategy_of_the_dinoflagellate_Symbiodinium

 

[Peer.Boerner]

@CHSUB - I’ve been following this thread and appreciate the information flow. But just so I understand your exact position, are you saying that we should try to achieve 0 nitrate because coral and other organisms will find nitrogen elsewhere? That nitrate is just one of many surrogates for available Nitrogen? Conceptually this makes sense to me but want to be sure I understand.

 

[sixty_reefer]

I would agree, however imo it is more common for mats to be associated with Cyanobacteria. When I see “mats” on-line in problem algae post, I believe it is a combination of nuisance algae. Here is a picture from Sprung in his algae book of a “mat” of dinoflagellate.

That was my thought. The dinoflagellates in your aquarium and probably most aquariums, don’t seem to form visible mats when they exist as normal part of the community.

 

[CHSUB]

are you saying that we should try to achieve 0 nitrate because coral and other organisms will find nitrogen elsewhere

Not exactly, my position is that we shouldn’t be afraid of “zero” no3 tested with hobby testing. With the understanding that nitrogen is available in multiple sources.

That nitrate is just one of many surrogates for available Nitrogen?

Yes! With fed fish nitrogen is abundant in nearly all closed systems.

Thanks.

 

[Lasse]

In ocean reefs no3 levels are so low that detection requires laboratory equipment, measurements are below 0.1 ppm no3.

The marine biologists I know and everything I have read about the nutrient values in the ocean claim that these low levels are due to NO3 being a nutrient-limiting form of inorganic nitrogen but also the storage form. NO3 is the form of inorganic nitrogen that does not by itself or is part of a process where the N part is released into the air in oxygenated parts of the ocean. The NH4/NH3 complex can partly disappear into the air, partly transform into nitrate but is usually the least energy-consuming organic nitrogen compound when absorbed and is therefore absorbed directly and locally. NO3 that does not leave the oxygenated part of the water and is converted from NH3/NH4 is thus an important reserve of inorganic nitrogen for photosynthesizing organisms - including the captured zooxanthellae of corals

I feed 10 ml of RS ab+, 1/16 teaspoon of reef Roids, and one pellet of mashed LPS food to corals directly daily. Fish and a sun coral share 1 cube of frozen daily. I believe my corals receive a large amount of particulate food, similar to ocean reefs. Directly feeding corals, imo, bridges the gap between keeping low nutrients and not starving corals. It is very doable as evidence of my grow sun coral that only survives on captured food.

I don’t believe this is “provocative”, imo it’s the easiest way.

That´s not much

That makes a lot of sense, however that is not how it works in ocean reef. Nitrates is nearly nonexistent in the oceans and even zooxanthella, a photosynthetic organisms, have adapted strategies to capture organic nitrogen.

https://www.academia.edu/105420762/...l_strategy_of_the_dinoflagellate_Symbiodinium

This article deal with free-swimming zooxanthella which it clearly say - my bold. Its not about captured zooxanthella. Whole article is attached below

Survival of free-living and symbiotic dinoflagellates ( Symbiodinium spp.) in coral reefs is critical to the maintenance of a healthy coral community. Most coral reefs exist in oligotrophic waters, and their survival strategy in such nutrient-depleted waters remains largely unknown. In this study, we found that two strains of Symbiodinium spp. cultured from the environment and acquired from the tissues of the coral Alveopora japonica had the ability to feed heterotrophically. Symbiodinium spp. fed on heterotrophic bacteria, cyanobacteria ( Synechococcus spp.), and small microalgae in both nutrient-replete and nutrient-depleted conditions. Cultured free-living Symbiodinium spp. displayed no autotrophic growth under nitrogen-depleted conditions, but grew when provided with prey. Our results indicate that Symbiodinium spp.’s mixotrophic activity greatly increases their chance of survival and their population growth under nitrogen-depleted conditions, which tend to prevail in coral habi.

Lately this article surfaced about gigant clams - a gene was discovered that indicates an active uptake and transport of nitrate from the water to the symbiont by the animal.

https://www.reef2reef.com/threads/i...-about-photosymbiosis-in-giant-clams.1160589/
Sincerely Lasse

 

[CHSUB]

also the storage form. NO3 is the form of inorganic nitrogen

When I test with sensitive equipment, ICP and Hanna LR, I get readable levels. So I assume since I feed sparingly, have active filtration, and perform weekly wc that no3 is never a limited nutrient in closed systems. Storage of no3 seems like an amazing evolutionary function. What do you consider a reasonable “storage” level in a closed system? In the ocean it appears to be < 0.1ppm?

That´s not much

Imo it is more than adequate…here is a long term chart of no3 levels in my aquarium tested with Hanna LR. The trend is upward so this indicates overfeeding while coral and mangroves growth is substantial, imo my feeding is not “limiting”. Zero readings were before I had the Hanna LR and was using Salifert. My first reading with Hanna LR was 0.07 ppm in July 2025.

This article deal with free-swimming zooxanthella which it clearly say - my bold. It’s not about captured zooxanthella. Whole article is attached below

The article says: “acquired from the tissues of the coral Alveopora japonica”
Study includes both free-swimming zooxanthella and symbiotic dinoflagellates ( Symbiodinium spp)

Lately this article surfaced about gigant clams - a gene was discovered that indicates an active uptake and transport of nitrate from the water to the symbiont by the animal

I look at the article when you originally posted and thanks. However this gene iirc was exclusive to clams. Still very interesting.

 

[Lasse]

The article says: “acquired from the tissues of the coral Alveopora japonica”
Study includes both free-swimming zooxanthella and symbiotic dinoflagellates ( Symbiodinium spp)

Now you read the text as the devil read the bible. Yes they was acquired from a coral but they was free swimming when the test was done - not in the captured phase - zooxanthella = another word for captured symbiotic dinoflagellates. Think twice - how would a dinoflagellate eat if it is surrounded by its host tissue - through a straw? The coral larvae capture free living Symbiodinium spp from the open water - the investigation you refer to ask itself how these dinoflagellates survive during the free living stage and they show that they could survive on only prey if NO3 was depleted and their photosynthesis did not working. The article did not show that they was heterotrophic when captured.

Sincerely Lasse

 

[Lasse]

. What do you consider a reasonable “storage” level in a closed system? In the ocean it appears to be < 0.1ppm?

I do not know but you must also have the mass transfer in mind. There is reports that both shows that NO3 is depleted over a reef and also some that have shown an increase when a water body pass through a reef. The problem can be that this 0.1 is the lowest level they can absorb because enrichment over this value has been shown to cause biological growth - the NO3 concentration has thus been growth-limiting. There is also another - for me - factor that I prefer NO3 concentrations around 2 - 3 mg/L. In a closed biological system - there is always a danger that to much H2S can be formed. It has been shown that NO3 concentrations above 2 in some way hinder these bacteria that have H2S as waste to grow.

If your system has been working - keep it that way but your system is not the only working system of the world.

Sincerely Lasse

 

[Lasse]

Excuse me - I forget the article I promised

Sincerely Lasse

 

[CHSUB]

If your system has been working - keep it that way but your system is not the only working system of the world.

Haha. Yes I would agree!

 

[PJfish]

Maybe a dumb question! but since nitrates do not evaporate will high rates of evaporation cause concentrated nitrates effectively elevating test numbers without water changes or plant/algae export ? Just topping off with rodi since some reefers do limited water changes especially on larger systems or fowler..Just wondering thanks!

 

[Dan_P]

I would agree, however imo it is more common for mats to be associated with Cyanobacteria. When I see “mats” on-line in problem algae post, I believe it is a combination of nuisance algae. Here is a picture from Sprung in his algae book of a “mat” of dinoflagellate.

OK, but here is myview.

From my observations of experimental aquaria, when you look at the mat will likely bias how you think about them. These mats are evolving communities, with changing dominant species. They can start out a nearly pure dinoflagellate culture that moves on to include cyanobacteria and then filamentous bacteria and ciliates. I have never been able to create two identical patches, making it difficult to describe the development trajectory.

 

[CHSUB]

Maybe a dumb question! but since nitrates do not evaporate will high rates of evaporation cause concentrated nitrates effectively elevating test numbers without water changes or plant/algae export ? Just topping off with rodi since some reefers do limited water changes especially on larger systems or fowler..Just wondering thanks!

It will not accumulate because of evaporation alone, unless your top off water includes some nitrates which is possible if not using Ro/di for example.

 

[Randy Holmes-Farley Verified Community Expert]

Yes, and thinking about it, I can’t recall seeing it happen often in mature aquariums either even in systems with undetectable nitrate and phosphate.

Which brings me back to the insurance question.

At what point do our aquariums stop needing dinoflagellate insurance?

It is also coral access to N insurance.

It seems to me the potential benefit of having a few ppm Nitrate outweighs any theoretical risk.