robert
Valuable Member
So cyano is a problem that from time to time dogs experienced and novice reefers alike.
FWIW there are probably over 1,000 strains of this bacteria - so we all tend to speak in generalities based on our personal experience - thats why there is so much seemingly contradictory advice on the subject.
With that said I dug up an old post I made a few years back...it probably is old info to some but to others, it might have a few tidbits of new information...
Old post...
This is a fun one...there are so many seemingly contradictory observations and just as many contradictory theories as how to eradicate cyano. I have had cyano in high flow, low flow, in high nutrient tanks, low nutrient tanks, with and without dino. I've had it under the best light sources as well as bad ones. In brand new tanks and fully mature tanks.
Invariably, in every post regarding cyano there are suggestions of treatments ranging from coral snow, chemi-clean. water-changes, antibiotics, gfo, vodka, bio-pellets, vinegar or bacterial dosing, all offered the ultimate treatment followed by the admonition that these are simply band-aids, to really get rid of cyano you have to fix the cause of the problem - nutrients.
But what does that mean exactly - if its that simple how can two tanks three feet apart. One with perfect chemistry, zero nitrate, zero phosphate have cyano, and the other a veritable nitrate/phosphate soup (my puffer tank) never see the stuff?
My favorite theory, at least for the moment, is the Nitrate/Phosphate balance theory. This model based on Redfield ratios holds that macro algaes (most life really) are comprised Carbon, Nitrogen, and Phosphorous in the general ratio of 106:C,16:N,1P. Sometimes Silica and Iron ratios are added in, but the 106:16:1 is enough to make sense of cyano and suggest a corrective course of action in all the conditions I describe above. In all cases the problem is rooted in phosphate. But that's impossible in practice - everything living in your tank needs phosphate to live and as Matt and his research points out phosphate readily binds to our rock work and sand. GFO can strip it from the water, you can export it with algae scrubbers, bacteria etc - maybe even get the reading to 0 on your tests - but there is always a ready pool lurking and every time you feed you add some more.
Let say your tank starts out with 0 phosphate and 0 nitrate. The food you use also conforms generally to the Refield ratios. You essentially are adding nitrogen and phosphorous in balance. Bacteria, and algaes - good and bad - can utilize the food (c:N
) to grow - some phosphate and some nitrogen escape getting eaten and get sequestered in your substrate. Some binds, nitrogen and phosphate both - and are taken out of circulation. But this binding doesn't follow the correct redfield ratio - much more phosphate binds leaving excess nitrogen floating around in the system.
Now you do a water change - more of the nitrogen gets taken out because its free - sure, some phosphate too - but all the bound phosphate gets left behind. So over time the total ratio of phosphate to nitrate in you tank shifts to elevated phosphate as nitrogen is constantly being carried off in water changes. (or outgassed as N2) Stuff - cyano included - need the balanced mix of 106C:16N:1P - to grow and multiply - so a competition for nitrogen ensues and cyano wins!
Why does cyano win? Because there is another source of nitrogen in your tank that most competing algaes and bacteria can't use but cyano can. That is nitrogen gas dissolved into the tank water from the air itself. So cyano can continue to grow while everything else is lacking the nitrogen to grow. Cyano becomes dominate - because it can grow and spread, it monopolizes the phosphate sources too! If your tank is relatively clean - low free phosphate - you'll see the phosphate first in the high flow areas because that is where cyano which can't move can catch the most phosphate in a low phosphate environment.
Now comes in the dino. Dino can't get it nitrogen from the gas dissolved in the water, but it can change the chemistry in its immediate environment to liberate phosphate from the sand and rock-work. So while cyano can monopolize the available phosphate in the water and starve everything else into submission - dino survives - and it too grows and multiplies. Now its much more diabolical than that, Dinos and cyano together seem to feed each other - dinos liberating phosphate for the cyano and cyano fixing nitrogen for the dinos!
All this because you changed your water and let you nitrates get out of balance to your phosphate sources...When has anyone told you your nitrates are too low? (Its not the right answer but close)
Sorry for all the typos and taking this thread into left field - That's enough for now. I'll post up some abstract if anyone wants - you can run down the articles from the titles - or message me and if any one still interested I'll post up some more later -
Later---
(Does this really happen? Not exactly as I described it but close enough, I have my own theory.)
"Heterotrophic dinoflagellates with symbiotic cyanobacteria and nitrogen limitation in the Gulf of Aqaba"
ABSTRACT: Many symbiotic associations characteristic of tropical and subtropical oceanic waters
were observed near shore during a long-term study of the microbiota in the northern part of the Gulf of
Aqaba, Red Sea. Among such associations were the heterotrophlc dinophysoid genera Omithocercus,
Histioneis and Citharistes with cyanobacterial symbionts. The detection of these heterotroph-autotroph
consortia repeatedly coincided with extended nitrogen limitation in the fall season. Populations of
free-living cyanobacteria, with known N fixation capability, such as the unicellular Synechococcus/
Synechocystis spp. and colonial forms, e.g. Trichodesmiurn spp., also peaked at the same time. We
propose that heterotrophic dinoflagellate hosts may provide the cyanobacterial symbionts with the
anaerobic microenvironment necessary for efficient N fixation. Thus, these self-supporting consortia
increase in numbers during the long period of stratification and nitrogen limitation in the oligotrophic
subtropical waters of the Gulf of Aqaba.
And another - lakes - but the same principle.
THE IMPACT OF NITROGEN AND
PHOSPHORUS CONCENTRATION AND
N/P RATIO ON CYANOBACTERIAL
DOMINANCE AND N2 FIXATION
IN SOME ESTONIAN LAKES
ILMAR TÕNNO
"Cyanobacteria appear responsible for most of planktonic N2fix in
aquatic ecosystems, this ability gives a significant competitive advantage to
these organisms during the periods of nitrogen limitation (Tilman et al., 1982;
Howarth et al., 1988a; Leppänen et al., 1988)."
many hypotheses have been presented to explain cyanobacterial dominance and blooms in lakes. One of the
most common is resource ratio competition theory, predicting that cyano-
bacteria tend to dominate in lakes where the ratio of nitrogen and phosphorus
(P) is low, mainly because of the ability of some of these species to use
molecular nitrogen (Elser 1999). This theory has been proved both empirically
and experimentally. Cyanobacteria, both fixing and not fixing N2, tend to
dominate if the ratio of total nitrogen (TN) and total phosphorus (TP) in the
water column is below ca. 5–10 by mass (Schindler 1977, Seip 1994, Michard
et al., 1996, Bulgakov & Levich 1999),
FWIW there are probably over 1,000 strains of this bacteria - so we all tend to speak in generalities based on our personal experience - thats why there is so much seemingly contradictory advice on the subject.
With that said I dug up an old post I made a few years back...it probably is old info to some but to others, it might have a few tidbits of new information...
Old post...
This is a fun one...there are so many seemingly contradictory observations and just as many contradictory theories as how to eradicate cyano. I have had cyano in high flow, low flow, in high nutrient tanks, low nutrient tanks, with and without dino. I've had it under the best light sources as well as bad ones. In brand new tanks and fully mature tanks.
Invariably, in every post regarding cyano there are suggestions of treatments ranging from coral snow, chemi-clean. water-changes, antibiotics, gfo, vodka, bio-pellets, vinegar or bacterial dosing, all offered the ultimate treatment followed by the admonition that these are simply band-aids, to really get rid of cyano you have to fix the cause of the problem - nutrients.
But what does that mean exactly - if its that simple how can two tanks three feet apart. One with perfect chemistry, zero nitrate, zero phosphate have cyano, and the other a veritable nitrate/phosphate soup (my puffer tank) never see the stuff?
My favorite theory, at least for the moment, is the Nitrate/Phosphate balance theory. This model based on Redfield ratios holds that macro algaes (most life really) are comprised Carbon, Nitrogen, and Phosphorous in the general ratio of 106:C,16:N,1P. Sometimes Silica and Iron ratios are added in, but the 106:16:1 is enough to make sense of cyano and suggest a corrective course of action in all the conditions I describe above. In all cases the problem is rooted in phosphate. But that's impossible in practice - everything living in your tank needs phosphate to live and as Matt and his research points out phosphate readily binds to our rock work and sand. GFO can strip it from the water, you can export it with algae scrubbers, bacteria etc - maybe even get the reading to 0 on your tests - but there is always a ready pool lurking and every time you feed you add some more.
Let say your tank starts out with 0 phosphate and 0 nitrate. The food you use also conforms generally to the Refield ratios. You essentially are adding nitrogen and phosphorous in balance. Bacteria, and algaes - good and bad - can utilize the food (c:N
) to grow - some phosphate and some nitrogen escape getting eaten and get sequestered in your substrate. Some binds, nitrogen and phosphate both - and are taken out of circulation. But this binding doesn't follow the correct redfield ratio - much more phosphate binds leaving excess nitrogen floating around in the system.Now you do a water change - more of the nitrogen gets taken out because its free - sure, some phosphate too - but all the bound phosphate gets left behind. So over time the total ratio of phosphate to nitrate in you tank shifts to elevated phosphate as nitrogen is constantly being carried off in water changes. (or outgassed as N2) Stuff - cyano included - need the balanced mix of 106C:16N:1P - to grow and multiply - so a competition for nitrogen ensues and cyano wins!
Why does cyano win? Because there is another source of nitrogen in your tank that most competing algaes and bacteria can't use but cyano can. That is nitrogen gas dissolved into the tank water from the air itself. So cyano can continue to grow while everything else is lacking the nitrogen to grow. Cyano becomes dominate - because it can grow and spread, it monopolizes the phosphate sources too! If your tank is relatively clean - low free phosphate - you'll see the phosphate first in the high flow areas because that is where cyano which can't move can catch the most phosphate in a low phosphate environment.
Now comes in the dino. Dino can't get it nitrogen from the gas dissolved in the water, but it can change the chemistry in its immediate environment to liberate phosphate from the sand and rock-work. So while cyano can monopolize the available phosphate in the water and starve everything else into submission - dino survives - and it too grows and multiplies. Now its much more diabolical than that, Dinos and cyano together seem to feed each other - dinos liberating phosphate for the cyano and cyano fixing nitrogen for the dinos!
All this because you changed your water and let you nitrates get out of balance to your phosphate sources...When has anyone told you your nitrates are too low? (Its not the right answer but close)
Sorry for all the typos and taking this thread into left field - That's enough for now. I'll post up some abstract if anyone wants - you can run down the articles from the titles - or message me and if any one still interested I'll post up some more later -
Later---
(Does this really happen? Not exactly as I described it but close enough, I have my own theory.)
"Heterotrophic dinoflagellates with symbiotic cyanobacteria and nitrogen limitation in the Gulf of Aqaba"
ABSTRACT: Many symbiotic associations characteristic of tropical and subtropical oceanic waters
were observed near shore during a long-term study of the microbiota in the northern part of the Gulf of
Aqaba, Red Sea. Among such associations were the heterotrophlc dinophysoid genera Omithocercus,
Histioneis and Citharistes with cyanobacterial symbionts. The detection of these heterotroph-autotroph
consortia repeatedly coincided with extended nitrogen limitation in the fall season. Populations of
free-living cyanobacteria, with known N fixation capability, such as the unicellular Synechococcus/
Synechocystis spp. and colonial forms, e.g. Trichodesmiurn spp., also peaked at the same time. We
propose that heterotrophic dinoflagellate hosts may provide the cyanobacterial symbionts with the
anaerobic microenvironment necessary for efficient N fixation. Thus, these self-supporting consortia
increase in numbers during the long period of stratification and nitrogen limitation in the oligotrophic
subtropical waters of the Gulf of Aqaba.
And another - lakes - but the same principle.
THE IMPACT OF NITROGEN AND
PHOSPHORUS CONCENTRATION AND
N/P RATIO ON CYANOBACTERIAL
DOMINANCE AND N2 FIXATION
IN SOME ESTONIAN LAKES
ILMAR TÕNNO
"Cyanobacteria appear responsible for most of planktonic N2fix in
aquatic ecosystems, this ability gives a significant competitive advantage to
these organisms during the periods of nitrogen limitation (Tilman et al., 1982;
Howarth et al., 1988a; Leppänen et al., 1988)."
many hypotheses have been presented to explain cyanobacterial dominance and blooms in lakes. One of the
most common is resource ratio competition theory, predicting that cyano-
bacteria tend to dominate in lakes where the ratio of nitrogen and phosphorus
(P) is low, mainly because of the ability of some of these species to use
molecular nitrogen (Elser 1999). This theory has been proved both empirically
and experimentally. Cyanobacteria, both fixing and not fixing N2, tend to
dominate if the ratio of total nitrogen (TN) and total phosphorus (TP) in the
water column is below ca. 5–10 by mass (Schindler 1977, Seip 1994, Michard
et al., 1996, Bulgakov & Levich 1999),
