Cyano's ? Ready for the battle?

[Belgian Anthias]

A lot is written concerning Cyano break outs and blooms.
But which cyano's are responsible for creating the inconvenience. Are it N2 fixing bacteria? Heterocysts forming N2 fixing Cyano's or non heterocysts forming N2 fixers. Maybe strains of Cyano's which can not fix nitrogen gas at all.
Which strains of cyano's are abundant in reef aquaria? Is it Trichodesmium, the unique diazotroph, abundant in our tropical and sub tropical seas and responsible for huge outbrakes ?
To win the battle it would be nice to know who we are fighting with and the weapons it is able to use.

 

[Brew12]

Is it Trichodesmium, the unique diazotroph, abundant in our tropical and sub tropical seas and responsible for huge outbrakes ?

While I would bet almost every reef tank has this in it, I doubt it is commonly a problem. It doesn't form the red mats that we associate with typical cyanobacteria outbreaks.

 

[Belgian Anthias]

Which strains of cyano's are responsible for red mats in a reef aquarium?

 

[Brew12]

Which strains of cyano's are responsible for red mats in a reef aquarium?

It could be any number of them (literally hundreds) and most likely a combination of many. I recommend people read this if they are having cyano issues.
http://www.pnas.org/content/105/32/11254?etoc="=

It explains how phosphorus reduction can be useful and how adding nitrates can shift growth away from N-fixing cyanobacteria strains. And keep in mind that cyano is part of the base food chain. Many things will eat it such as rotifers, copepods, amphipods, some snails, hermit crabs, and even some fish.

 

[Belgian Anthias]

It could be any number of them (literally hundreds) and most likely a combination of many. I recommend people read this if they are having cyano issues.
http://www.pnas.org/content/105/32/11254?etoc="=

It explains how phosphorus reduction can be useful and how adding nitrates can shift growth away from N-fixing cyanobacteria strains. And keep in mind that cyano is part of the base food chain. Many things will eat it such as rotifers, copepods, amphipods, some snails, hermit crabs, and even some fish.

This assumes that N2 fixing filamentous cyanobacteria ( heterocyst forming or not heterocyst forming?) are forming the mats . Doesn't they are able to grow faster when they do not have to fix nitrogen as they need much less energy following the normal pathway.
The article is about the situation in a fresh water lake where heterocyst forming cyanobacteria are abundant. This is not the case in a tropical marine environment, where non heterocyst forming N2 fixing cyano's rule.
Once heterocysts are formed they can not go back and can only transform to a vacuole and go in a stationary phase waiting for the end. They are not able to compete with other specimen which have not formed heteorcysts yet due to enough nitrogen compounds. In lakes they form mats that may float for regulation of the lightintensity by regulating the depth. Those cyano's are very sensitive for to much light and will die at a light intensity present in the tropics at +-3m of depth.

It seems to me that in a tropical marine aquarium the situation may be completely different compared to the situation in the recommended article. It would be nice to know which strains are responsible for the mats in a reef aquarium.

 

[Brew12]

It seems to me that in a tropical marine aquarium the situation may be completely different compared to the situation in the recommended article. It would be nice to know which strains are responsible for the mats in a reef aquarium.

This would be a wonderful thing! Unfortunately, I don't believe that a hobbyist with a microscope (even a good one) can make that identification. Without that identification, we can only guess as to possible solutions other than grazers.

This is not the case in a tropical marine environment, where non heterocyst forming N2 fixing cyano's rule.

This study does address this, albeit not in a tropical environment.

"As we found in the 227 trophic cascade experiment described above, in large mesocosm experiments using near full-strength seawater from Narragansett Bay, RI, nitrogen fixers prospered, and nitrogen fixation occurred as long as the abundance of grazing zooplankton was low (31, 32). Normal concentrations of zooplankton were able to suppress cyanobacteria populations by grazing, keeping colonies too small to form heterocysts. "


And I do appreciate the link! I'm looking forward to studying it!

 

[Belgian Anthias]

Knowing what kind of filamentous mat forming bacteria are responsible for outbreaks in the conditions of a reef aquarium is crucial to understand how we can fight them.
N2 fixing by heterocysts or without heterocists, during the night or in aerobic conditions during the day. Are only N2 fixing cyano's forming mats? or also non N2 fixing specimen?
As a lot of N2 fixing cyano's may store phosphate for 3 to 4 cell divisions these trains can increase biomass x32 without any nitrogen compounds or phosphate present. Removing as much phosphate possible may form a plague due to removing other competitors for the same phosphate. When some phosphate comes available after feeding there will be very little competition as there affinity for phosphate is higher as most competitors. They are able to use phosphate at very low concentrations, before most other and faster growing organisms. In fact, VLNS are ideal for cyano's to rule.
As there is little or no commercial profit in research about which strains cyano are responsible for outbrakes in a tropical seawater aquarium we need support of universities who have the opportunity and means to carry out this research.
No master students out there who are interested to make there end work about cyano outbreaks in a reefaquarium? And the role of competition for nutrients for controlling and prevent such outbreaks. Maybe such research exists already for marine aquaculture systems?

 

[Belgian Anthias]

This would be a wonderful thing! Unfortunately, I don't believe that a hobbyist with a microscope (even a good one) can make that identification. Without that identification, we can only guess as to possible solutions other than grazers.


This study does address this, albeit not in a tropical environment.

"As we found in the 227 trophic cascade experiment described above, in large mesocosm experiments using near full-strength seawater from Narragansett Bay, RI, nitrogen fixers prospered, and nitrogen fixation occurred as long as the abundance of grazing zooplankton was low (31, 32). Normal concentrations of zooplankton were able to suppress cyanobacteria populations by grazing, keeping colonies too small to form heterocysts. "

The solution is enough nutrients to support the competitors. Introducing phytoplankton and some of its consumers to start a food chain from star up.
Once a favourable situation for cyano's is created, which are most LNS, it is very difficult to do something when its happens without leaving the LNS philosophy.

The problem with grazers is the fact that a toxic foodchain may be created. An other reason why it is important to know which strains of cyano"s are responsible for the break outs in the limited environment of the aquarium. Cyano's which are not grazed on are probably to toxic.

Light , light temperature and intensity are main parameters for cyano growth. High light intensities may control and even kill them ( using a spotlight)

Forming heterocysts is a question of nitrogen compounds availability. When the competitors use up the nitrogen compounds in a way there is not enough left over they will form heterocysts. I do not think it has something to do the colonies are small or big. Of coarse a big colony will be encountered faster with a shortness compared to smaller colony. I think the competition for phosphate is more important than N2 fixing ability. Why it is assumed that a cyano outbreak is in relation with N2 fixing? And with the forming of heterocysts? They are able to grow a lot faster when not fixing nitrogen gas as a lot less energy is needed and the pathway is a lot shorter.

Non heterocysts forming N2 fixers start to fix nitrogen when there is a shortness in there micro environment. They may switch from nitrogen source very fast. . This is not possible for heterocyst forming cyano's They need a different approach for controlling them.

 

[Brew12]

I do not think it has something to do the colonies are small or big. Of coarse a big colony will be encountered faster with a shortness compared to smaller colony.

It has nothing to do with the size of the colony, but length of the bacterial chains. Heterocysts are formed evenly spaced throughout the bacterial chain. If that chain is never grown long enough due to grazing then the heterocysts will not be formed.

I think the competition for phosphate is more important than N2 fixing ability.

Why it is assumed that a cyano outbreak is in relation with N2 fixing?

I think both are important based on a what the studies show. They show that the availability of nitrogen in sources other than nitrogen gas alter the composition of that biomass. When there is plenty of NO3, the biomass shifts toward dinoflagellates and algaes. When NO3 is limited the biomass shifts toward cyanobacteria. I do agree that phosphorous is also critical. Not only does it impact N2 fixing, but it also limits total biomass in the absence of other limitations.

 

[Belgian Anthias]

It has nothing to do with the size of the colony, but length of the bacterial chains. Heterocysts are formed evenly spaced throughout the bacterial chain. If that chain is never grown long enough due to grazing then the heterocysts will not be formed.



I think both are important based on a what the studies show. They show that the availability of nitrogen in sources other than nitrogen gas alter the composition of that biomass. When there is plenty of NO3, the biomass shifts toward dinoflagellates and algaes. When NO3 is limited the biomass shifts toward cyanobacteria. I do agree that phosphorous is also critical. Not only does it impact N2 fixing, but it also limits total biomass in the absence of other limitations.

Yes, every +-10 cells in the filament. In this theory filaments do not get longer than +- 10 cells?
For example, when a filament of + 50 cells is brought into nitrogen compounds limited conditions 5 heterocists may be formed. If half the filament is removed before heterocysts are formed or afterwards, I suspect the left over ability to fix nitrogen will be about the same. I do not believe grazing will prevent forming heterocysts. If biomass is removed the capability will be in order of what is left over.

Which studies are we talking about? Are they typical for a tropical marine environment?
I thought that in a tropical marine environment diatoms are dominant. This may not be the case in the limited environment of a closed marine system.
I follow the theory of biomass production as phytoplankton grow rates are a lot higher compared to cyano's, even compared to non heterocysts forming cyano's which are abundant in low nutrient tropical marine waters. In high nutrient conditions cyano growth will be limited due to the competition for building materials.

 

[Belgian Anthias]

Most theories for controlling cyano growth is based on growth wile N2 fixing and on heterocyst forming cyano's but in what extent they are present in cyano break outs in a tropical marine aquarium?

 

[Brew12]

Which studies are we talking about? Are they typical for a tropical marine environment?

Unfortunately, most of them are done in lakes. However, this one was done in warmer, Florida coastal waters.
https://www.int-res.com/articles/meps2004/280/m280p073.pdf

but in what extent they are present in cyano break outs in a tropical marine aquarium?

It would be nice if someone would perform this testing. I feel the costs for the testing have made it prohibitive for what is effectively a hobby. Since cyanobacteria tends to be easily controlled in marine aquariums, larger public aquariums are not pressured into putting resources into this.

 

[Belgian Anthias]

Prevention is always better as curing. And then we are talking about leaving the LNS philosophy.

One can keep natural nutrient levels following different ways. What we measure is what is left over. When the readings are 0 this may be good but also very wrong. Keeping measurable levels may help in controlling this levels. That is what I try to do.

Any information about research concerning tropical marine cyano's is welcome.

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