Low nutrient levels=Dinos? What?

[Kenneth Wingerter]

I keep seeing threads where people seem to be suggesting that their low or "zero" readings of nitrate and/or phosphate are leading to, or could lead to, outbreaks of dinoflagellates. This makes no sense to me, and in over 25 years of keeping/selling corals I've yet to hear that one until recently. Where does that theory even come from? Are there any data out there, or even a model, that suggests how this could happen?

 

[Marlon C]

It's 0 phosphate thar results in dino. Dino is better then other algea at uptaking the little po4 in a tank. I've raised my po4 and dinos went away

 

[Dan_P]

I keep seeing threads where people seem to be suggesting that their low or "zero" readings of nitrate and/or phosphate are leading to, or could lead to, outbreaks of dinoflagellates. This makes no sense to me, and in over 25 years of keeping/selling corals I've yet to hear that one until recently. Where does that theory even come from? Are there any data out there, or even a model, that suggests how this could happen?

It is a popular narrative for a complicated situation and there is very little proof of its validity.

I suspect the rational is partially correct but is missing other factors, such as, “new system”, “a too soon and too rapid introduction of livestock”, and “light intensity”. The narrative is based on anecdotal data of those who have the problem but does not include examples where dinoflagellates do not occur under the conditions that are supposed to cause outbreaks.

Right now, it is the top idea we have.

 

[taricha]

As personally one of the biggest proponents of the idea, I'll say it gets mis- and over-stated.
The idea grew out of the converse: "You can't get rid of nuisance dinos by starving PO4 in a reef tank." This has been seen a lot, and is more easily supported.
In fact, the most typical story for a dino outbreak is that the hobbyist had algae issues and ran a lot of GFO to push PO4 down to super low levels, the other algae disappears and brown slime takes over that later gets ID'd as dinos. If they keep pushing PO4 down to virtually the limits of detection by of Ultra low range meters, the brown slime doesn't budge.
All this means is that dinos have ways of handling low PO4, and can access untestable organic sources of P better than their competitors (you still have to feed your fish!), and PO4 starvation isn't great for a reef system anyway.

But I've seen people do really illogical stuff based on this idea too. "I have brown uglies and high PO4, so I must need EVEN HIGHER PO4..."
Or push PO4 to 1.0ppm etc. :-(

If you have algae and high NO3, PO4 bring them down to sane levels. But don't starve PO4. if you have super low PO4 and dinos, remove the PO4 starvation, allow competitors and manage the algae other ways. herbivores, algae scrubbers etc.

That's probably my best overall advice on the nutrient side after watching this play out with peoples systems for a few years.

The narrative is based on anecdotal data of those who have the problem but does not include examples where dinoflagellates do not occur under the conditions that are supposed to cause outbreaks.

I might misunderstand you, but I did once pour multiple 10mL additions of brown water with microscope ID'd ostreopsis dinos from an infected nano into my display that had recently gotten over a dino outbreak and had PO4 levels ~0.10 that in my system at the time didn't support dinos.
They struggled to form a stray bubble here or there, then disappeared.

posted that here

Is PO4 the only variable of interest? no, it's more complicated and Dan reminds me, we're missing important parts of the story still. But you can create conditions where even introduction of dinos don't cause outbreaks. too bad we don't know exactly what those conditions are!

 

[Garf]

Only makes sense to me if decaying algae from ultra low phos, is feeding the dinos, which I have suspected for years. Algae scrubbers used to be regularly infected by “brown growth” which I suspect was in fact dinos. Algae exudates can also be a food for dinos, even without low phos etc, but in lower concentrations.

 

[Dan_P]

Only makes sense to me if decaying algae from ultra low phos, is feeding the dinos, which I have suspected for years. Algae scrubbers used to be regularly infected by “brown growth” which I suspect was in fact dinos. Algae exudates can also be a food for dinos, even without low phos etc, but in lower concentrations.

Funny, I was just thinking about algae scrubbers. I got rid of mine when I no longer wanted it. Now I can’t find dinoflagellates anymore. I am reinstalling one in hopes of bringing them back for research purposes.

@taricha and I have discussed the coincidence of some species of dinoflagellates and GHA growth. Algae, both micro and macro algae, dump organic molecules to the surrounding water. Just because we don’t algae, it could still be present at a level sufficient to fuel microorganism growth.

 

[attiland]

0 phosphate and /or nitrate cause instability for sure and it is known for dinos taking advantage of this situation.
I have and would do dose nitrate and phosphate if it would go to undetectable levels. The idea is that we try to keep competition of Dinos up at all cost.

Nitrate and phosphate is essential for a lot of life in the tank that includes corals invertebrates and unfortunately algae too.

Fighting dinos for many stains benefits from higher levels for sure but not all. I think thinking about them as one treatment works for all is wrong. There are stains where the only working treatment is to trigger the bloom of diatoms with silicates dosing while keeping nitrate and phosphate levels high.

Read the Dino treads almost all stories start like this. “ I have introduced something made my phosphate or nitrate go 0 and a week or so I have dinos”. Of course the Dinos were already there but never were detectable but with the new situation of water condition caused them to thrive while their competitors diapered.

So yes I truly believe there is a chance that 0 phosphate or nitrate can indirectly cause Dino outbreak.

 

[lelandmarine]

Good discussio, always worth reviewing

 

[living_tribunal]

I keep seeing threads where people seem to be suggesting that their low or "zero" readings of nitrate and/or phosphate are leading to, or could lead to, outbreaks of dinoflagellates. This makes no sense to me, and in over 25 years of keeping/selling corals I've yet to hear that one until recently. Where does that theory even come from? Are there any data out there, or even a model, that suggests how this could happen?

It's not theory, it's science. Dino does not depend on "nutrients" to the degree that other bacteria and micro/macro algae do. It can perform photosynthesis in waters heavily depleted of N/P. What happens is dino is triggered by a rapid change in "nutrient" levels, typically when inorganic phosphates decrease. This effectively signals to dino that it can come out and will be free to grow without competition.

 

[Garf]

It's not theory, it's science. Dino does not rely on "nutrients" to survive. It can exist purely off photosynthesis. What happens is dino is triggered by a rapid change in "nutrient" levels, typically when phosphates hit 0. This effectively signals to dino that it can come out and will be free to grow without competition.

Photosynthesis is not possible without some form of carbon, phosphate and nitrogen. It may be organic form though, instead of inorganic. It cannot create something out of nothing but light.

 

[Crustaceon]

I keep seeing threads where people seem to be suggesting that their low or "zero" readings of nitrate and/or phosphate are leading to, or could lead to, outbreaks of dinoflagellates. This makes no sense to me, and in over 25 years of keeping/selling corals I've yet to hear that one until recently. Where does that theory even come from? Are there any data out there, or even a model, that suggests how this could happen?

The thing is, it “can” cause dinos but like everything else in this hobby, there is some nuance to it. I’ve always seen it as a biological competition issue. When phosphates bottom out, typically with low nitrates, bacteria propagation will “stall out”. We see this all the time with carbon dosing and it’s easily reproducible. We all see the end result when dinos fill the role left open by beneficial bacteria on the sand bed. Once nutrient levels rise, bacteria will typically bloom and in many cases, dinos will disappear. So it might not actually be the low nitrates/phosphates per-se that is causing dinos but an environment that’s less conducive to bacterial growth which is allowing the dinos to out-compete bacteria for that space.

 

[living_tribunal]

Photosynthesis is not possible without some form of carbon, phosphate and nitrogen. It may be organic form though, instead of inorganic. It cannot create something out of nothing but light.

I think we often confuse 0 detectable levels and "bottoming out" with complete elimination. This is why the focus is on "rapid" change with levels decreasing. Nothing has been 100% proven regarding the dinos we often hear about in our tanks, but science shows strong correlations between sudden drops in nutrient levels to the onset of benthic dinos HABs. The following experiment was conducted on a type of amphidinium

"We further found that under P-deficient condition, overall photosystem II quantum efficiency (Fv/Fm ratio) and Rubisco abundance decreased but not significantly, while cellular contents of carbon, nitrogen, and proteins increased significantly. These observations indicated that under P-deficiency, this dinoflagellate was able to continue photosynthesis and carbon fixation, such that proteins and photosynthetically fixed carbon could accumulate resulting in continued cell growth in the absence of division. This is likely an adaptive strategy thereby P-limited cells can be ready to resume the cell division cycle upon resupply of phosphorus."

Furthermore, every study that exists shows that dino toxicity skyrockets under P limited conditions. Also, there is a specific type of dino, the one they refer to as “red tide” that is specifically induced by p limitation.

The one common factor for dinos is their high ability to utilize dissolved organic phosphates for atp. So it’s more of a competitive chain situation. The study continues to show that growth rates in dino are very similar under replete and deplete conditions. This however is in isolation. When you factor in the competitive landscape, things change quite a bit.

 

[saltyhog]

I think we often confuse 0 detectable levels and "bottoming out" with complete elimination. This is why the focus is on "rapid" change with levels decreasing. Nothing has been 100% proven regarding the dinos we often hear about in our tanks, but science shows strong correlations between sudden drops in nutrient levels to the onset of benthic dinos HABs. The following experiment was conducted on a type of amphidinium

"We further found that under P-deficient condition, overall photosystem II quantum efficiency (Fv/Fm ratio) and Rubisco abundance decreased but not significantly, while cellular contents of carbon, nitrogen, and proteins increased significantly. These observations indicated that under P-deficiency, this dinoflagellate was able to continue photosynthesis and carbon fixation, such that proteins and photosynthetically fixed carbon could accumulate resulting in continued cell growth in the absence of division. This is likely an adaptive strategy thereby P-limited cells can be ready to resume the cell division cycle upon resupply of phosphorus."

Furthermore, every study that exists shows that dino toxicity skyrockets under P limited conditions. Also, there is a specific type of dino, the one they refer to as “red tide” that is specifically induced by p limitation.

The one common factor for dinos is their high ability to utilize dissolved organic phosphates for atp. So it’s more of a competitive chain situation. The study continues to show that growth rates in dino are very similar under replete and deplete conditions. This however is in isolation. When you factor in the competitive landscape, things change quite a bit.

Great post. The last sentence says a lot IMO. Anything that seems to provide more competition helps in fighting dinos. Unfortunately super low PO4 affects the competition MUCH more than it does dinos(or as you cited...almost not at all for dinos).

 

[taricha]

The following experiment was conducted on a type of amphidinium

This would be similar to our small-cell amphidinium types.

The study continues to show that growth rates in dino are very similar under replete and deplete conditions. This however is in isolation. When you factor in the competitive landscape, things change quite a bit.

Right. The other thing to point out here is that the cell doubling time for our problem dinos is slow - relatively. The above "model organism" still only doubles every day or so.
Some dinos (prorocentrum) double so slowly that they can't keep up with a 24 hour cycle so they have no particular division time of day.

here's some data

Only the small-cell amphidinium type had a div/day of nearly 1. Prorocentrum, Gambierdiscus, Ostreopsis, and Coolia all had max of 0.5 to 0.8 divisions/day.


other single-cell photosynthetic organisms can double much faster. Dinos seem well suited to lower nutrient and slower divisions. under more replete conditions, they can't keep up with diatoms etc.

 

[living_tribunal]

This would be similar to our small-cell amphidinium types.


Right. The other thing to point out here is that the cell doubling time for our problem dinos is slow - relatively. The above "model organism" still only doubles every day or so.
Some dinos (prorocentrum) double so slowly that they can't keep up with a 24 hour cycle so they have no particular division time of day.

here's some data

Only the small-cell amphidinium type had a div/day of nearly 1. Prorocentrum, Gambierdiscus, Ostreopsis, and Coolia all had max of 0.5 to 0.8 divisions/day.


other single-cell photosynthetic organisms can double much faster. Dinos seem well suited to lower nutrient and slower divisions. under more replete conditions, they can't keep up with diatoms etc.

I think this is exactly it. It’s not that a quick drop in nutrient levels is the specific catalyst that leads to Dino HAB, it’s more so an indirect response by the lack of competition and the Dinos ability to effectively prepare and take off the second even a minor replete condition occurs.

 

[zalick]

I'll add my anecdotal experience to support the generate proposition that dinos out-compete at ultra low levels of PO4.

I've been keeping reefs for nearly 25 years. For 20 years I never chased PO4 and frankly never tested for it. My tanks would be considered high nutrient tanks. I never had dinos and actually had never even heard of them.

My current tank has been running for about 6 years. It set it up as a ULN tank because that's all the rage. I aggressively ran gfo to keep my PO4 at undetectable levels. Then dinos absolutely exploded. I actually thought it was algae so I increased my Gfo. I later learned it was Coolio dinos using a microscope.

As soon as I started dosing nitrates a PO4, and took GFO offline, the dinos started to lose the competition and recede.

After reading all of the dino threads it became clear to me that not all ULN systems had dino issues but rather virtually all dino issues were in ULN systems.

It also seems that dinos have become a much bigger issue in the last 5-10 years than it was in the 90s and ealry 2000s.

 

[biophilia]

I think that a lot of scenarios that are imagined to be about arbitrary specific levels of macronutrients are in actuality about the role of limiting nutrients that are not being tested by most aquarists. And also about grazing pressure present in the specific aquarium.

Dinoflagellates and benthic cyanobacteria are both examples of organisms that can dominate the substrate in an aquarium when particular micronutrients are limited, but can be fairly easily out-competed by organisms (like diatoms) that are more palatable to herbivores when those limiting nutrients are addressed.

Feeding more, doing large water changes, etc may, on the surface, appear to address the issue by manipulating fairly arbitrary NO3/PO4 concentrations or ratios when in fact it’s addressing it by adding something else ( like some bio-available silicate to a silica-limited environment).