What are the root causes of Cyano?

[Hans-Werner]

What I am missing in your experiment is a tube with a few grains of coral sand rich in phosphate. I think cyanobacteria are superior in the utilisation of phosphate deposits and can still grow on these phosphate deposits when corals already suffer phosphate limitation. Together with the ability of phosphate storage this in my eyes is a main reason for cyano blooms.

 

[taricha]

As do most bacteria, Cyano prefere ammonia as a nitrogen source. When using nitrate-nitrogen the growth rate is slowed down. As cyano, part of a microbial matt, are normally coverd by heterotrophs using up most ammonia one may considder there normal growth rate is based mainly on the consumption of nitrate-nitrogen and ammonium-nitrogen produced within the matt. The parameters of nitrate and phosphate in the watercolumn do not matter much ( for the cyano in the film) exempt when there is not enough.
...
As the growth rate of heterotrops controls the availabilty of oxygen and ammonia in the layers, the availabilty of usable organic carbon in the water column may play a main role in the growth rate of cyano and other photo-autotrophs.

I think I get what you are suggesting. Carbon dose dramatically increased activity of heterotrophs which got greedy and consumed ammonia etc so it was unavailable to cyano.
Would large vinegar doses actually keep cyano at bay in a system? That would cut against a lot of hobby conventional wisdom. hmm....

What I am missing in your experiment is a tube with a few grains of coral sand rich in phosphate. I think cyanobacteria are superior in the utilisation of phosphate deposits and can still grow on these phosphate deposits when corals already suffer phosphate limitation. Together with the ability of phosphate storage this in my eyes is a main reason for cyano blooms.

funny you should mention that.
the next iteration of the tests will include a sand substrate, and I had them all ready to go with dead seaweed under clean new aragonite sand. Then I remembered how much P fresh aragonite can bind, and that nothing would grow. :-(
So I'll recycle some used sand from a tank with plenty of P instead. Or maybe I'll just pre-soak the fresh aragonite in P-rich media.
That's a really interesting idea that the cyano film might access the PO4 bound in the sand grains. I wonder if that's testable.

 

[Dan_P]

What I am missing in your experiment is a tube with a few grains of coral sand rich in phosphate. I think cyanobacteria are superior in the utilisation of phosphate deposits and can still grow on these phosphate deposits when corals already suffer phosphate limitation. Together with the ability of phosphate storage this in my eyes is a main reason for cyano blooms.

Hello @Hans-Werner ! As @taricha has said, the search for the ideal conditions for cyanobacteria growth is moving towards considering the environmental factors: light and surface type. Up to this point, growing luxurious cyanobacteria mats as found in our aquarium is no simple matter. Cyanobacteria seem to require much more than a simple increase in phosphate or nitrate.

We are also wondering why a nasty pest like cyanobacteria is so timid and polite in our test tubes. What is it about the aquarium setting that allows cyanobacteria to be a bully but only meekly blushes at us inside a test tube. Recent research demonstrates that aerobic heterotrophic bacteria grow as partners with cyanobacteria. Do our culture medium somehow fail to nurture this partnership which might be behind the nasty and persistent cyanobacteria mat? We are trying to look into this as well as surface conditions and light.

 

[Dan_P]

I think I get what you are suggesting. Carbon dose dramatically increased activity of heterotrophs which got greedy and consumed ammonia etc so it was unavailable to cyano.
Would large vinegar doses actually keep cyano at bay in a system? That would cut against a lot of hobby conventional wisdom. hmm...

You have knack for asking questions! I have one for you.

What was the mL of vinegar per gallon of medium ratio? One possible problem with dosing vinegar is destroying/reducing the bicarbonate buffer in the test tube. Cyanobacteria can derive their CO2 needs by consuming bicarbonate. The vinegar might have given the heterotrophic bacteria a head start by feeding it AND limiting cyanobacteria CO2 intake, at least initially.

One more factor we can check: CO2 limitation. By adding additional bicarbonate to the medium, cyanobacteria growth in captivity might increase.

 

[Dan_P]

As do most bacteria, Cyano prefere ammonia as a nitrogen source. When using nitrate-nitrogen the growth rate is slowed down. As cyano, part of a microbial matt, are normally coverd by heterotrophs using up most ammonia one may considder there normal growth rate is based mainly on the consumption of nitrate-nitrogen and ammonium-nitrogen produced within the matt. The parameters of nitrate and phosphate in the watercolumn do not matter much ( for the cyano in the film) exempt when there is not enough.
Most cyano are able to store phosphate for 4 cel divisions which makes them competitive to other PAO ( Phosphate Acumulating Orgamisms) for other essential building materials.

As the growth rate of heterotrops controls the availabilty of oxygen and ammonia in the layers, the availabilty of usable organic carbon in the water column may play a main role in the growth rate of cyano and other photo-autotrophs.

This is a fascinating subject. If cyanobacteria weren’t such slimy things!

The cyanobacteria-aerobic heterotrophic community is likely to be a very complex metabolic process. At a very cursory level, the digestion of particulate and dissolved organic carbon by the heterotrophs can generate ammonia and nitrogen containing compounds that the cyanobacteria can benefit from. In return the carbon rich exudates from the cyanobacteria will be consumed by the heterotroph along with oxygen. The additional benefit of this internal carbon dosing is the potential for the heterotroph to metabolize more recalcitrant dissolved organic carbon compounds and providing even more nitrogen to the cyanobacteria. This positive feedback may explain why cyanobacteria in an aquarium seems so resistant to any change, as you also point out about nitrate and phosphate in the water column.

 

[taricha]

What was the mL of vinegar per gallon of medium ratio? One possible problem with dosing vinegar is destroying/reducing the bicarbonate buffer in the test tube. Cyanobacteria can derive their CO2 needs by consuming bicarbonate. The vinegar might have given the heterotrophic bacteria a head start by feeding it AND limiting cyanobacteria CO2 intake, at least initially.

1 drop per maybe ~30mL so very roughly 1.5 mL per Liter, or somewhere around 6 mL vinegar per Gallon. It's a lot.
That's like 5 times more than maximum amount I did a few years ago - that I decided was too much because it caused stringy bacteria growth all over my system.

 

[Alistairn1]

In my experience (which is very limited) I learned quickly that flow is probably one of the most important factors in any aquarium (just look at the oceans, they’re never still!) I also included good sand turners like sand sifting stars, gobies and the odd snail to really get through a thick bed, some wrasse’s will also do a good job but there is always the knock on effect of clouding the water with too much agitation of your substrate. Cyano has never returned since!

 

[Hans-Werner]

Recent research demonstrates that aerobic heterotrophic bacteria grow as partners with cyanobacteria? Do our culture medium somehow fail to nurture this partnership which might be behind the nasty and persistent cyanobacteria mat?

I also have wondered whether heterotrophic bacteria play a role in cyanobacterial growth. But why should cyanobacteria, bacteria themselves, be in a mutualistic partnership with heterotrophic bacteria. Cyanobacteria themselves can do fermentation themselves under low oxygen conditions in the dark. Nevertheless it looks like they are dependet from bacterial films growing between cyanobacterial mat and substrate.

My theory is that either the cyanobacteria themselves or a film of heterotrophic bacteria produces organic acids to dissolve phosphate from the substrate. Under conditions of phosphate limitation they make use of phosphate deposits in rock and sand in this way.

Sometimes it is reported that cyanobacterial mats "disappear" in the afternoon. I also observed this and I think they moved into the sand to get to deeper phosphate deposits and make use of the higher phosphate concentrations of interstitial waters after their internal phosphate reserves got exhausted by divisions.

So I'll recycle some used sand from a tank with plenty of P instead. Or maybe I'll just pre-soak the fresh aragonite in P-rich media.

I don't think the sand has to be especially rich in phosphate. Usually even fresh coral sand from the bag should do it. It usually isn't especially low in phosphate. In tanks I think that a reduction of the phosphate concentration from between 0.1 ppm and 0.2 ppm to 0.05 ppm or less in the water can favor a cyanobacterial bloom. I think a gradient in the phosphate concentration between sand and water is the trigger.

 

[Dan_P]

I also have wondered whether heterotrophic bacteria play a role in cyanobacterial growth. But why should cyanobacteria, bacteria themselves, be in a mutualistic partnership with heterotrophic bacteria. Cyanobacteria themselves can do fermentation themselves under low oxygen conditions in the dark. Nevertheless it looks like they are dependet from bacterial films growing between cyanobacterial mat and substrate.

Our experiments are directed at discovering conditions that promote “luxurious” cyanobacteria mats, the kind of growth that is very disturbing to aquarium owners. We can grow thin cyanobacteria films quite readily. Our question: what conditions promote the formation of thick films?

My theory is that either the cyanobacteria themselves or a film of heterotrophic bacteria produces organic acids to dissolve phosphate from the substrate. Under conditions of phosphate limitation they make use of phosphate deposits in rock and sand in this way.

Just a thought. Carbonic acid will dissolve aragonite. Maybe with enough CO2 being produced in the substrate, phosphate can be liberated to encourage faster cyanobacteria growth. @brandon429 has described the accumulation of organic matter in substrate and its association with nuisance organism growth on the substrate. Digestion of this material might be generating an acid environment in the substrate.

Sometimes it is reported that cyanobacterial mats "disappear" in the afternoon. I also observed this and I think they moved into the sand to get to deeper phosphate deposits and make use of the higher phosphate concentrations of interstitial waters after their internal phosphate reserves got exhausted by divisions.

Filamentous cyanobacteria will also shade themselves in the substrate when the light becomes too bright. In an an aquarium with constant light levels (presumably the light isn’t being modulated to simulate brighter afternoon conditions) I would agree that the cyanobacteria might be moving into the substrate for nutrient reasons, looking for more CO2, NH3/NO3, and phosphate.

I don't think the sand has to be especially rich in phosphate. Usually even fresh coral sand from the bag should do it. It usually isn't especially low in phosphate. In tanks I think that a reduction of the phosphate concentration from between 0.1 ppm and 0.2 ppm to 0.05 ppm or less in the water can favor a cyanobacterial bloom. I think a gradient in the phosphate concentration between sand and water is the trigger.

I don’t understand how a phosphate concentration gradient would enable luxurious cyanobacteria film formation. What is the mechanism?

Might we instead be witnessing a roughness of surface phenomenon? A situation that enables the accumulation of particulate organic carbon?

 

[taricha]

Sometimes it is reported that cyanobacterial mats "disappear" in the afternoon. I also observed this and I think they moved into the sand to get to deeper phosphate deposits and make use of the higher phosphate concentrations of interstitial waters after their internal phosphate reserves got exhausted by divisions.

Agreed on the observation of cyano mats appearing lighter in afternoon as the cyano strands move down into sand.

And Dan’s data seems to suggest that a P limitation is stronger barrier than limitations of other most other nutrients. So that may indeed be what they are hunting for between the sand grains.

 

[taricha]

I think y'all are on to something.

My theory is that either the cyanobacteria themselves or a film of heterotrophic bacteria produces organic acids to dissolve phosphate from the substrate. Under conditions of phosphate limitation they make use of phosphate deposits in rock and sand in this way.

Just a thought. Carbonic acid will dissolve aragonite. Maybe with enough CO2 being produced in the substrate, phosphate can be liberated to encourage faster cyanobacteria growth. @brandon429 has described the accumulation of organic matter in substrate and its association with nuisance organism growth on the substrate. Digestion of this material might be generating an acid environment in the substrate.

The pH drop associated with benthic mats is frequently reported. Though it never occurred to me that the lower pH might liberate what's bound in the aragonite surface.
This paper [Photosynthesis and structure of benthic microbial mats(pdf)] found a swing of nearly 2 full pH points from 8.9 to 7.0 separated by just over 1 mm of depth.

That seems pretty extreme (and it's in a salt lake - not the ocean), but I bet you don't need that much to start liberating some goodies from the sand grains.

 

[Dan_P]

Agreed on the observation of cyano mats appearing lighter in afternoon as the cyano strands move down into sand.

And Dan’s data seems to suggest that a P limitation is stronger barrier than limitations of other most other nutrients. So that may indeed be what they are hunting for between the sand grains.

Yeah phosphate seems like amazingly stuff.

In experiments where nitrogen is limiting though, increasing the amount of phosphate seems to have little or no effect on cyanobacteria growth. Also, cyanobacteria can grow only so fast. Adding more nutrients like phosphate will not increase its growth rate. In an aquarium, there will be a level of phosphate above which adding more phosphate will not increase cyanobacteria growth.

The take away lesson for me is that talking about the importance of a single nutrient to growth has to be relative to the concentration of the other nutrients. So, yes phosphate is important, but it will only have a visible effect if the organism’s growth is not limited by another nutrient, light or space. There is really nothing special about phosphate’s “power” to stimulate cyanobacteria growth in a test tube unless it is a limiting reagent. Then it seems like a magic elixir of life.

 

[Dan_P]

I think y'all are on to something.




The pH drop associated with benthic mats is frequently reported. Though it never occurred to me that the lower pH might liberate what's bound in the aragonite surface.
This paper [Photosynthesis and structure of benthic microbial mats(pdf)] found a swing of nearly 2 full pH points from 8.9 to 7.0 separated by just over 1 mm of depth.

That seems pretty extreme (and it's in a salt lake - not the ocean), but I bet you don't need that much to start liberating some goodies from the sand grains.

Thanks for this. Yes, these types of profiles exist for substrate pore water in ocean substrates. It still is very hard for me to imagine chemical gradients being set up over such a tiny distance. In the relatively still waters of an aquarium, I wonder what the gradients are.

 

[Jose Mayo]

Do not forget iron, as a factor limiting or increasing cyanobacterial proliferation...

The Challenge of Iron Stress in Cyanobacteria

Regards

 

[Dan_P]

Do not forget iron, as a factor limiting or increasing cyanobacterial proliferation...

The Challenge of Iron Stress in Cyanobacteria

Regards

Thank you for this information link. Very informative.

I provide chelated iron (II) to my cultures of cyanobacteria. They have not paid me back with vigorous growth, suggesting that I am limiting them in some other manner. The reference you provided discusses other metals that I should consider adding.

Dan

 

[taricha]

I did a handful of experiments that centered around the movement of oscillatoria cyanobacteria. Here are 3 I like best. Some were surprising (to me at least), and a bit of a paradox.

First, an intentional experiment with a very sideways outcome. A 3+ foot clear plastic tube half full of water that I filled with a slurry of oscillatoria. The spotlight is because I intended it as a phototaxis/photobleaching experiment, but it ended up as something else - the fastest cyano I've ever seen.

At the beginning, the clumps, strands and cells were spread evenly throughout the entire length of the over 3 foot tube - the water was red everywhere. 6 minutes later, the cyano had begun to pull together across the width of the tube. Again, I had intended this to be a lighting experiment, with some of the cyano getting photobleached under the spotlight. Instead after only 25 minutes the strands had pulled on each other and collapsed the entire 3+ feet down to under a foot long string of cyano. The capacity for collective movement blew me away.

Second, What happens if you constrain a live happy cyano mat under a beaker?
The beaker collected bubbles (mostly O2 - looks like several mL) and the luxurious mat became a thin film.

Bottom left is a closeup of the thin cyano film on the sand. Bottom right shows the thin film spread the entire inner surface of the beaker (the cyano film on exterior of the beaker was wiped clean before pics so all filaments visible are on the inside of the glass). The inside roof of the beaker was also colonized by cyano film.

And Third, here's a low power microscope time lapse of oscillatoria clumping up 3 times.
Oscillatoria clumping part 1
This was out of focus, so before things got going too much, I stopped and restarted the time lapse, so most of the action can be found in part 2.
Oscillatoria clumping part 2 (I recommend watching at 1/4 speed)

There are 3 clumping events. All in the same dish, all with the same cyano strands shaken and re-separated between each event. The first two, light is coming from bottom right, and the clumps move toward the top right which seems the darkest part of the well. To see if this was a light-driven choice (negative phtotaxis away from harsh light), I moved the light source to come from the upper left for the 3rd clumping event. The clump ends up in the same spot in the well.

observations:
clumping direction of motion is not phototaxic, it's driven by the grippy-ness of the surface. Fastest motion occurs when chunks of mat lose contact with the dish entirely.
the strands grab virtually every bit of debris and drag it with them
the vicinity of greatest motion seems to be where strands are stretched the most.
each progressive re-clumping even took much longer than the one before it. Cell energy output getting tapped out? Or maybe if the motion is from straight filaments grabbing at both ends and twisting/coiling up in the middle, then maybe the cyano was running out of straight un-coiled strands to pull the mass together.

 

[Dan_P]

I did a handful of experiments that centered around the movement of oscillatoria cyanobacteria. Here are 3 I like best. Some were surprising (to me at least), and a bit of a paradox.

First, an intentional experiment with a very sideways outcome. A 3+ foot clear plastic tube half full of water that I filled with a slurry of oscillatoria. The spotlight is because I intended it as a phototaxis/photobleaching experiment, but it ended up as something else - the fastest cyano I've ever seen.

At the beginning, the clumps, strands and cells were spread evenly throughout the entire length of the over 3 foot tube - the water was red everywhere. 6 minutes later, the cyano had begun to pull together across the width of the tube. Again, I had intended this to be a lighting experiment, with some of the cyano getting photobleached under the spotlight. Instead after only 25 minutes the strands had pulled on each other and collapsed the entire 3+ feet down to under a foot long string of cyano. The capacity for collective movement blew me away.

Second, What happens if you constrain a live happy cyano mat under a beaker?
The beaker collected bubbles (mostly O2 - looks like several mL) and the luxurious mat became a thin film.

Bottom left is a closeup of the thin cyano film on the sand. Bottom right shows the thin film spread the entire inner surface of the beaker (the cyano film on exterior of the beaker was wiped clean before pics so all filaments visible are on the inside of the glass). The inside roof of the beaker was also colonized by cyano film.

And Third, here's a low power microscope time lapse of oscillatoria clumping up 3 times.
Oscillatoria clumping part 1
This was out of focus, so before things got going too much, I stopped and restarted the time lapse, so most of the action can be found in part 2.
Oscillatoria clumping part 2 (I recommend watching at 1/4 speed)

There are 3 clumping events. All in the same dish, all with the same cyano strands shaken and re-separated between each event. The first two, light is coming from bottom right, and the clumps move toward the top right which seems the darkest part of the well. To see if this was a light-driven choice (negative phtotaxis away from harsh light), I moved the light source to come from the upper left for the 3rd clumping event. The clump ends up in the same spot in the well.

observations:
clumping direction of motion is not phototaxic, it's driven by the grippy-ness of the surface. Fastest motion occurs when chunks of mat lose contact with the dish entirely.
the strands grab virtually every bit of debris and drag it with them
the vicinity of greatest motion seems to be where strands are stretched the most.
each progressive re-clumping even took much longer than the one before it. Cell energy output getting tapped out? Or maybe if the motion is from straight filaments grabbing at both ends and twisting/coiling up in the middle, then maybe the cyano was running out of straight un-coiled strands to pull the mass together.

Your time lapse photography rivals your uses of the visible spectrometer in revealing the wonders of our reef aquaria.

We should start a Go-Fund me page for your research.

 

[Jose Mayo]

Thank you for this information link. Very informative.

I provide chelated iron (II) to my cultures of cyanobacteria. They have not paid me back with vigorous growth, suggesting that I am limiting them in some other manner. The reference you provided discusses other metals that I should consider adding.

Dan

Chelating agents are species-specific, the use of chelated iron may prevent its use according to which organisms.

Regards

 

[Dan_P]

This is good to know. I have been using the gluconate of iron (II), hoping the Spirulina can use it. I haven’t found a source that recommends chelating agents by cyanobacteria specis,

 

[Jose Mayo]

This is good to know. I have been using the gluconate of iron (II), hoping the Spirulina can use it. I haven’t found a source that recommends chelating agents by cyanobacteria specis,

Cyanobacteria in general, and many other bacterial species, have the ability to produce siderophores, which are iron chelators. Each species exhibits, on its surface and in its cellular biochemical mechanisms, specific receptors for the siderophores that produce, but not for the others. Therefore, IMO, the best form of administration would be ferric sulfate, or ferrous sulfate, not chelated iron.

Iron‐limited growth of cyanobacteria: Multiple siderophore production is a common response

Best regards