What are the root causes of Cyano?

[Sallstrom]

I think to biggest problem is that most aquarist are looking for a quick solution. And cyanobacteria is an opportunist and do well when something changes in the tank(nutrients, light schedule etc). So IMO the best way to control cyano is to do everything slow, and if you change something, give it some time efterwards to get back to stable conditions.

In the tanks I run at work I also see that cyano will start to come when nitrate gets under 1ppm. And since i'm a bit lazy and don't want to clean the sand that often I want to give the aquarium the chance to manage the cyano by itself. I only adjust the nitrate(and phosphate is that is needed) by adding KNO3 or lowering the carbon source. The additives are dosed by dosing pumps so it can be done slow and during a couple of weeks time. No other changes is done and usually the cyano will go away in 1-3 weeks. Again, this is for tanks with low nutrients. And it might be easier with tanks that have been running for a while.

For tanks with more nutrients it's harder to find the right balance. I'm sure you can run a tank with higher nutrients without cyano, we have several of those as well. I think the issue here is also the stability of everything. IMO it's not a question about high or medium nutrients in this case. Maybe more the relation between N and P and if the nutrient levels are being the same over time or not.

I can add that I don't like to add anything in our tanks that I don't know the content of And therefor I prefer not to use Chemi clean or similar products.

/ David

 

[brandon429]

We cured it above not by dosing nutrients nor measuring them. Just by removing detritus which actually seems like nitrogen removal...?

A recurring theme i use in my tank correction threads is not ever asking for nor requiring nutrient testing. We’re getting mass mileage still across tanks simply attacking the invader at hand. Dinos included. So my claimed cause is natural vectoring + hesitation...

It seems that those who cannot rinse the bed must choose dosing of X to win the battle, but I can’t see how lack of something is causing dinos or cyano while we’re collecting win after win having never asked for nutrient measures. Lack of hand grazing seems to be the cause of ails across tanks.

 

[Hans-Werner]

It is not that simple. That some cyanobacteria can fix nitrogen does not mean nitrogen starvation is a prerequisite for a cyanobacterial bloom. I had mats of cyanobacteria adding nitrogen to the tank and clearly phosphate was the minimum factor. A cyanobacterial bloom can be provoked by adding amino acids also containing nitrogen.

 

[brandon429]

I see what you mean, the mats were bringing in N from the air and contributing to overall N sourcing?

 

[Lasse]

It is not that simple. That some cyanobacteria can fix nitrogen does not mean nitrogen starvation is a prerequisite for a cyanobacterial bloom. I had mats of cyanobacteria adding nitrogen to the tank and clearly phosphate was the minimum factor. A cyanobacterial bloom can be provoked by adding amino acids also containing nitrogen.

I´m not talking of nitrogen fixation from the cyanobacteria because the ones that concerns us can´t fixate nitrogen by themselves – they lack heterocyst. I´m talking of the reason why the jelly and hence the mats will develop. One of the triggers for that is nitrogen starving.

From another thread

Cyanobacteria can secretate extracellular polymeric substances (EPS) consisting mainly of polysaccharides. The cyanobacteria can produce polysaccharide envelopes surrounding the entire cell or colony. Nitrogen deficiency is a well-known factor that stimulates the secretion of jelly (Stal 2000). In the absence of nitrogen, protein synthesis stagnates while photosynthesis can continue. Under such conditions, the cyanobacteria accumulate large amounts of glycogen (Allen& Smith 1969; Lehman & Wöber 1976). The cell's capacity to store glycogen is limited and excess carbohydrates are secreted as jelly.

What´s happen below the mats after they had been build up is intresting from a nitrogen fixation point of wiev and also according to phosphate sources

Sincerely Lasse

 

[Hans-Werner]

Thank you, Lasse!
There are cyanobacteria that fix nitrogen without heterocysts, either in specialized cells or places other than heterocysts or at night when they are oxygen consumers themselves.
Nevertheless they may form mats despite the presence of nitrogen compounds. Maybe they form the jelly from the added organic carbon compounds???

 

[JasPR]

Do every other day 20% water changes with RO/DI water and bacteria like algae growth will be zero. To me, at least, that proves it is organic / nitrate/ phosphate driven. Rich pellets drop a certain ‘post digestion’ fertilizer into the ambient water parameters. PS always have a high quality skimmer running

 

[Lasse]

Thank you, Lasse!
There are cyanobacteria that fix nitrogen without heterocysts, either in specialized cells or places other than heterocysts or at night when they are oxygen consumers themselves.
Nevertheless they may form mats despite the presence of nitrogen compounds. Maybe they form the jelly from the added organic carbon compounds???

There can be other triggers. I (and David at Sjöfartsmuseet Akvariet - a public aquarium in Gothenburg) have notice some relationship with dosing organic compounds and forming of cyanobacteria mats. (see David’s post 21 in this thread). If this because of NO3 levels goes down or something else – I do not know. But standard proceedings in my aquaria (and in Davids) when signs of Cyanobacteria mats show up are to lower the carbon dosing and/or add KNO3.

It’s a little bit surprising because organic carbon ought to rise the number of heterotrophs and speeding up the breakdown process, hence release more inorganic nitrogen in the form of NH4. But maybe – the denitrification process in some aquaria will be speeded up by the organic carbon and you create a nitrogen limited situation that way

Sincerely Lasse

 

[Lasse]

that proves it is organic / nitrate/ phosphate

For the book - nitrate and phosphate are inorganic compounds

Sincerely Lasse

 

[sk8elenex92]

It seems like I start getting some cyano when my nitrates and phos are very low. I start feeding a bit more and it slowly goes away.

 

[Hans-Werner]

But standard proceedings in my aquaria (and in Davids) when signs of Cyanobacteria mats show up are to lower the carbon dosing and/or add KNO3.

When I started my experiments with the dosage of nutrients about twenty years ago I elevated the nitrogen supply to get lowest possible phosphate concentrations. (After some years I found out that this approach was a mistake.) Back then I had around 20 ppm NO3 according to test kits by dosing urea(!). Nevertheless I had cyano mats which started to "go underground" in the afternoon and reappeared in the morning after the lights had switched on. Since the cyanos cannot have been N-limited they must have been P-limited. They went into the bottom gravel to fill up their P-stores (presumably polyphosphates) from the interstitial waters rich in phosphate. In the morning they reappeared with freshly filled P-stores to do photosynthesis and grow until in the afternoon the P-stores got depleted and again the cyanos started to go underground.

NO3 does not only supply nitrogen, it alters the ORP and it is a oxygen source for facultatively anaerobic bacteria. I am quite convinced that it alters the phosphate availability to corals (which also turned out in my experiments), presumably by elevating the internal pH. So if NO3 is the main N-source it alters a lot of things, not only the N-concentration and the N-availability. In my eyes it cannot be the N-availability only that causes cyano blooms. In my eyes it is more often P-deficiency and/or reduced competitiveness of corals and coralline algae that causes cyano blooms.

 

[Randy Holmes-Farley]

NO3 does not only supply nitrogen, it alters the ORP and it is a oxygen source for facultatively anaerobic bacteria. I am quite convinced that it alters the phosphate availability to corals (which also turned out in my experiments), presumably by elevating the internal pH.

Why would the external nitrate concentration impact the internal pH of cyanobacteria?

In my eyes it cannot be the N-availability only that causes cyano blooms. In my eyes it is more often P-deficiency and/or reduced competitiveness of corals and coralline algae that causes cyano blooms.

In general, I don't see a mechanism that lower levels of anything nontoxic (such as phosphate) will make something grow better unless it is changing the competition between it and some other organism for something critical (trace elements, space to grow, etc.).

 

[Lasse]

When I started my experiments with the dosage of nutrients about twenty years ago I elevated the nitrogen supply to get lowest possible phosphate concentrations. (After some years I found out that this approach was a mistake.) Back then I had around 20 ppm NO3 according to test kits by dosing urea(!). Nevertheless I had cyano mats which started to "go underground" in the afternoon and reappeared in the morning after the lights had switched on. Since the cyanos cannot have been N-limited they must have been P-limited. They went into the bottom gravel to fill up their P-stores (presumably polyphosphates) from the interstitial waters rich in phosphate. In the morning they reappeared with freshly filled P-stores to do photosynthesis and grow until in the afternoon the P-stores got depleted and again the cyanos started to go underground.

NO3 does not only supply nitrogen, it alters the ORP and it is a oxygen source for facultatively anaerobic bacteria. I am quite convinced that it alters the phosphate availability to corals (which also turned out in my experiments), presumably by elevating the internal pH. So if NO3 is the main N-source it alters a lot of things, not only the N-concentration and the N-availability. In my eyes it cannot be the N-availability only that causes cyano blooms. In my eyes it is more often P-deficiency and/or reduced competitiveness of corals and coralline algae that causes cyano blooms.

Interesting

First remark is that you use Urea – it means that the primary inorganic nitrogen species would have been ammonia/ammoniac (NH4/NH3). If it changes anything – I do not know but in the long run – probably no

I still see our Cyanobacteria only be problematic when they form the mats – after the mats have been constructed – they are like self-playing pianos and fix their nutrients by themselves through many pathways. Normally they are always in our aquarium – behave themselves like all normal photosynthetic organism does. But suddenly something trigs the formation of this jelly that we call mats. In the quote, post 25, the authors make a brilliant description what’s happen in the absence of nitrogen – and I believe that explanation

However – as you – I have seen cyanobacteria mats in water with high nitrogen content. And even in system with both inorganic nitrogen and phosphorus in the water column.

I wonder if their description (and mechanism) also will fit in according to all defiance of all important compounds of the cell building process – like phosphorus, iron and other substances/atoms.

If the building of cell structure stops but the photosynthesis still works – the forming of the mats will occur with help of the production of sugar from the photosynthesis. And then the magic beyond the mats will start and a bloom is a fact.

Another interesting thing, as you stated – the mats seems to disappear during night-time (no photosynthesis) and slowly building up under the light period.

I can see two possible explanations for that:

The cells disappear in the substrate to pick up something

or more likely for cyanobacteria

The extracellular sugar (that the mats consist of) is used as energy sources during reproduction (read cloning) of the bacteria cells. Its happen during daytime also but during night time no new production of sugar happens because lack of photosynthesis and the storage (the jelly/mat) will be smaller

For the moment I will change my statement why the mats will be formed – from nitrogen starvation to starvation of something that its essential in the cell structure.

However – why can the photosynthesis keep going and still produce sugar. Sugar is C, H and O -> carbon, hydrogen and oxygen. The source of C for the photosynthesis is CO2 or HCO3 or CO3 It’s for me unknown if our beloved cyanobacteria strains has the ability to convert HCO3 or CO3 to CO2. If they can do that – they need energy and we does not know if these cyanobacteria are strictly autotrophs or if they I some situation can use organic carbon (This can be the link to why stopping organic carbon dosing can give some help)

Source of H and O – the water itself

How to fight them?

Its depend on.

I will still in a first try dose NO3 with the assumption that they get their phosphorus through the anaerobic conditions and production of hydrogen sulphide below the mat. Look at NO3 in this case – not as a nutrient but as game changer of the bacteria system below the mats.

If I suspect that they can get the phosphorus through bacteria digestion (other bacteria) of overload of organic matter below the mats – disturb the mats. And I it some type of true in the assumption that they can use the jelly as energy source – remove them

Stop my dosing of organic carbon – especially if I use sugar in the mix

I will also be sure that that my inorganic N and P (NH4/NH3 NO2, NO3, NOx and PO4) nor are close to Zero.

In my experiences – the NO3 trick works in more than 50 % of the cases I heard about – for me – it has been working for nearly all times I have had buildings of mats.

The theory that I have try to outline above can also give an explanation why well-maintained aquarium with a stable biological environment will be rather free for cyanobacteria mats and will also explain why its so common among ULN systems

I have no idea if the things I have write above has with the truth to do or not, but I think it will give one possible explanation to all contradicting reports we have got according to explain and defeat the building of benthic cyanobacteria mats

Sincerely Lasse

 

[Brew12]

For the moment I will change my statement why the mats will be formed – from nitrogen starvation to starvation of something that its essential in the cell structure.

Have you considered that limiting factor isn't directly impacting the cyanobacteria itself?

I think it should at least be considered that the conditions in these systems (high NO3) aren't ideal for cyanobacteria but that it is the biologics that should be out competing them which are nutrient limited. With the competition hitting a nutrient limit it may allow the cyanobacteria to form mats in less than ideal parameters.

I would love to try to adding iron, manganese and/or silicate into a system like this and see what happens.

 

[Hans-Werner]

Why would the external nitrate concentration impact the internal pH of cyanobacteria?



In general, I don't see a mechanism that lower levels of anything nontoxic (such as phosphate) will make something grow better unless it is changing the competition between it and some other organism for something critical (trace elements, space to grow, etc.).

The assimilation of nitrate raises the internal pH of corals (the same in algae or cyanobacteria). Assimilation of NO3- by organisms means formation of amino groups from NO3-. This process consumes protons. It is balanced by the uptake of protons from the aqueous solution or the excretion of OH- into the aqueous solution. As you know the removal of H+ from an aqueous solution or the excretion of OH- means raising pH.

If you grow plants and you take either NH4+ or NO3- as fertilizer you will notice that their mode of action is quite different.

To describe the cyano problem for the whole tank it is a P-deficiency that can be observed. I think it is reduced competition of corals and coralline algae for iron that causes the cyano bloom but it may also be another mechanism of competition.

 

[Hans-Werner]

First remark is that you use Urea – it means that the primary inorganic nitrogen species would have been ammonia/ammoniac (NH4/NH3). If it changes anything – I do not know but in the long run – probably no

Believe me, there is a difference. I used urea and at some point I wanted to try the dosage of nitrate. I calculated the amount of the nitrate compound for the same N supply and started automated dosing of nitrate instead of urea. Everything seemed fine and a few weeks later I left into holidays. The aquaria where my job. After I returned a Montipora plate had severly bleached and partially died because the dosage of nitrate instead of urea made a difference after the urea was completely consumed and the corals had to assimilate nitrate. I think the uptake of nitrate interferes with the uptake of phosphate somehow. There are new scientific publications that show up that nitrate, in contrast to other nitrogen compounds, is detrimental to corals.

Why did I use urea? It is a non-toxic form of ammonia. Corals prefer ammonia over nitrate as source of N. The hydrolysis of urea elevates pH and this process is meant to take place during calcification of corals. The enzym urease is proven for corals which means they can make use of urea as N source. Micro algae (zooxanthellae are micro algae) take up urea and ammonia from low concentrations with high affinity.

 

[Lasse]

Do you believe that the corals are able to take urea directly from the water and hence do the change to NH4/NH4 inside the CORAL or will this transformation take place outside of the coral tissue?

Sincerely Lasse

 

[Hans-Werner]

Good afternoon Lasse. The participation of urease and the hydrolysis of urea in calcification only makes sense when urea is taken up by the coral and hydrolyzed at the sites of calcification.

 

[jumplittlechloe]

Everything seemed fine and a few weeks later I left into holidays. The aquaria where my job. After I returned a Montipora plate had severly bleached and partially died because the dosage of nitrate instead of urea made a difference after the urea was completely consumed and the corals had to assimilate nitrate. I think the uptake of nitrate interferes with the uptake of phosphate somehow. There are new scientific publications that show up that nitrate, in contrast to other nitrogen compounds, is detrimental to corals.

Interesting, I have had a similar experience. My tank is running nitrate and phosphate limited (NO3 and PO4 not measurable on testing kit). I saw my sps were losing color. I also have cyano mats on my rock and sand. I decided to start dosing 2ml of sodium nitrate solution I mixed in an attempt to raise nitrates. I could not get a reading for nitrate so I started to increase my dosage to 2x daily and eventually went to 2ml 2x daily. I could never get a NO3 reading but what I did get was my sps started to show signs of tissue loss. I have stopped dosing and still have cyano and no measurable NO3 or PO4.

I bought some Flourish Nitrogen by Seachem which does contain urea but it also has potassium nitrate. From your conclusions it sounds like I may end up with the same results.

 

[jsker]

This is some great information and reading @Lasse @Hans-Werner @Sallstrom

@aeras1131 get job on the topic