Thoughts on cyanobacteria

[asylumdown]

I've always thought there was something more going on with cyanobacteria than the common forum wisdom about algae has let on. Namely, it's because I've seen every single probable cause and remedy for it stated as though it's a fact - cyano thrives in low nutrient tanks, cyano is a sign of excess nutrients, cyano thrives when one nutrient is depleted relative to the other, cyano only occurs in low flow, cyano can occur anywhere, etc. etc. etc. Every single aquarium 'case' has at one point been blamed for cyano, even mutually exclusive cases. Also, other than chemical treatments like chemi-clean, there's not really an easy way to knock it out once it starts growing. I've seen cyano at some point in just about every tank I've seen in person, or seen pictures of online, regardless of the husbandry practice. True some tanks get it worse than others, and I lean towards thinking that high nutrients in general help it get out of control, but something about it has never really added up to me. I got really interested in it when I had a massive cyano explosion in my first tank upon adding biopellets, because so far, no one's been able to offer a good explanation as to why that happens. The best explanation I've seen is that since cyano is a bacteria and not a true algae, it's somehow able to capitalize on the sloughed off carbon polymers that make it in to the water column.

In any case, I have a small patch that started in the corner of my tank that's been slowly expanding for a couple of weeks. My tank is pretty darn close to ULN status, and no other algae really grows in my tank, and yet, day after day, the patch of cyano is advancing up the glass. It's the red wine coloured, slimy mat forming kind that I'm sure just about everyone has seen before.

Since I have a microscope now, I decided to look at it under magnification. I took two samples, one I pulverized in some tank water so that it was just reddish coloured water, and the other that I put on a slide relatively intact. The pulverized sample showed me exactly what the internet told me to expect, long strands of single cell chains of garden variety cyanobacteria. It was the intact sample that was really interesting. At low magnification, the cyano formed a tight weave that looked like a basket, but it was throbbing, almost like it had a pulse. At higher magnification, it was clear that was was causing the movement was thousands upon thousands of some other species of bacteria (diatoms maybe?) that were sliding in/amongst/through the threads of cyano. There were also much larger (but still invisible to the naked eye) worms actively sliding along, and a few spots of what appeared to be highly motile dinoflagellates.

I took a short video:


I edited it for the highlights. As you can see, the motile single cell organisms (bacteria? diatoms?) are almost as numerous as the strands of cyano, and they were pervasive and evenly spaced throughout the entire sample. All in all, the piece of 'cyano' that's presently in my tank is actually a living conglomeration of 4 distinct species of micro-organism, with cyano really only being the scaffold upon which the others seem to live. I'm starting to wonder if the red colour isn't at least being partially contributed by the motile organisms and not the cyano itself.

I've looked at my sand, rock scrapings, tank water, dino outbreaks and all number of bio-films and slimes under my microscope, and I've never seen what appears to be such an intentional and consistent assemblage of organisms all living together. I tried doing a cursory search of 'cyano ecology' online and didn't find anything (there might be something and I just haven't found it), but from what I saw, to me it's starting to look as though the mats of 'cyano' that we can see at the macro scale in our tanks are actually a lot more complex than a simple blue-green algae. I have no idea how the things that make up the mat in my tank influence each other, who's eating who, or if there really is a relationship beyond the cyano providing an ideal substrate, but if there is some sort of synergistic relationship between the cyano and the things that live in it, I wonder if that might explain why cyano 'outbreaks' seem so baffling in some cases. Just like how a forest can set up enough feedback loops that it can begin to create the conditions necessary for it to spread, I'm wondering if the relationships between the cyanobacteria and it's commensal organisms are actually working together to support the development of the entire colony (which is the mat that we see) thus making their little 'forest' much more resilient in a broader range of environmental conditions.

I posted this on the Canadian reef forum but thought that maybe the folks who talk in here might also have some comments on this. Am I out to lunch? Is this nothing more than a bunch of things living together and I'm seeing a possible link that isn't there?

 

[disc1]

One of the reasons that you see so many varied causes and cures for cyano is that there are a LOT of different types of cyano. The group has been around longer than just about anything else on earth. Up to 3.5 Billion years depending on who you believe. They've evolved through myriad different conditions and that has left them just about indestructible.

As long as it isn't growing everywhere I prefer to let a little cyano grow. Especially in the refugium. You won't find anything anywhere that will do so much to clean and stabilize your water. The only drawback is the ugly factor.

 

[Sk8r]

fascinating video. It's tough stuff. Depends only on an energy source (light), carbon (common to living things) and water. That makes it pretty tough stuff.

 

[triggreef]

Interesting read. The only place I have it is in my 60g sump, which right now only has a dsb in the refuge portion of it. The sand bed is covered in clumps of it, but there is none in the display. And not much other algae in the display, beside some caulerpa that has maintained status quo for a couple months, really no new growth. Now I'm thinking of it, I only need to scrape the glass about once for every 4 or 5 times on my other tank, despite very heavy and dirty feedings (Puffer eats messy).

 

[Squidmotron]

You guys amaze me. Seriously.

 

[Cac986]

One of my observations of cyanobacteria is that this gram negative prokaryotic cell is becoming far more prevalent in home aquariums then in the past. Why is that??? Well my best answer is that we are experiencing more resistant strains. They form a biofilm for protection and within this biofilm are other symbiotic bacteria. The use of antibiotics is to blame for this. Erythromycin is the antibiotic found in most commercial antidotes of cyano. However, gram negative bacteria in general are far more virulent and difficult to kill. So, we as aquarists have used (most of us) erythromycin in the past and had positive results. But, if not dosed correctly (strength, frequency and duration) some cyano becomes resistant to the antibiotic. Now we have a resistant pathogen that is being passed on from one tank to the other in our trade. I also have read everything there is to know about cyano and as you said there are many different theories out there, not all correct. There are other antibiotics that we use in humans to treat pseudomonas, e.coli etc that my have a better kill rate then erythromycin. Levofloxacin, gentamicin, amikacin, tobramycin, and aztreonam to name a few that would work. These antibiotics, with the exception of levofloxacin, do not have a broad spectrum and are specifically used for gram negative bacteria. One import point is will these antibiotics be harmful to fish, inverts, and coral? One thing that I can tell you is that using antibiotics especially broad spectrum ones will destroy your biological filtration system and the normal flora of our aquariums.

Bacteria in our aquarium are normal, in fact cyano bacteria has been on the planet for millions of years, as someone pointed out earlier. So I would argue that every piece of live rock, live sand has cyanobacteria. But, when one bacterium is killed off by whatever, change in water chemistry etc.... opportunistic bacteria such as cyanobacteria will proliferate to compete for space.

In conclusion we as hobiest need to stop using antibiotics to avoid more resistant strains of cyanobacteria. Remove the biofilm manually to protect the coral, and the only cure is to wait for your tanks normal flora to become back in balance.

 

[Ron Reefman]

Cac986, you may be right, but I have an additional factor you might consider.

The increase in food for the cyano that we now put into our tanks MUCH more than in the past. Cyano is a bacteria and feeds on carbon, right? That's my understanding and I certainly don't claim any expertise in this area. So tell me if you know I'm wrong.

How long has vodka dosing and other carbon additives been getting dosed into some of our tanks? 6 years? 8 years? And then we started seeing bio-pellet reactors that also release carbon into the water supply. The idea being we feed bacteria and some bactria form that process nitrate (and/or phosphates... I'm not sure on that point as I don't have nitrate or phosphate issues... yet). At the same time we are putting food out where for the cyano bacteria as well.

 

[Cac986]

Ron. I agree that there are other variables that cause cyano outbreaks. Carbon is a food source for all bacteria. Carbon is ubiquitous and the basis of all living things. Its possible that vodka dosing is providing a food source for all bacteria in our systems. But why would this cause cyano to out compete other bacteria? What I can say is that if the water conditions are more favorable for one bacteria it will out compete the other. What these conditions are is debatable.

 

[gone fishin]

I don't really know much about all the biology of bacteria. But for something that is a "simple" organism to have been around millions of years it has to be one tough critter.

I really enjoyed the video.

 

[Ron Reefman]

Ron. I agree that there are other variables that cause cyano outbreaks. Carbon is a food source for all bacteria. Carbon is ubiquitous and the basis of all living things. Its possible that vodka dosing is providing a food source for all bacteria in our systems. But why would this cause cyano to out compete other bacteria? What I can say is that if the water conditions are more favorable for one bacteria it will out compete the other. What these conditions are is debatable.

I agree with you but I'm not sure I understand why you think cyano is out competing the others? People start media reactors to grow bacteria that process nitrates. Some work well and some get cyano. And the most common reply to people who do get cyano is to dial back the reactor. Other bacteria that help do grow and work on nitrates. So is cyano just another bacteria, or one that starts to flourish if the tank is fed too much carbon? I don't know the answer. I've been lucky to have very few issues with it and I don't dose vodka or run a media reactor.

 

[Cac986]

I agree with you but I'm not sure I understand why you think cyano is out competing the others? People start media reactors to grow bacteria that process nitrates. Some work well and some get cyano. And the most common reply to people who do get cyano is to dial back the reactor. Other bacteria that help do grow and work on nitrates. So is cyano just another bacteria, or one that starts to flourish if the tank is fed too much carbon? I don't know the answer. I've been lucky to have very few issues with it and I don't dose vodka or run a media reactor.

I don't dose vodka or have a media reactor. So far I have been lucky with alot of live rock, protein skimmer,phos/carbon reactor and a large refugium. I try very hard to take the basic concepts that I learned in microbiology when working on my doctorate and apply these basic principles to my reef aquarium hobby or shall I say obsession. Bacteria are constantly at battle with each other whether in the aquarium, human GI tract, or the film on our shower. They are competing for space, and will use many different techniques to do so. So all of these bacteria are keeping each other in check, and if one colony of bacteria dies off for whatever reason the more opportunistic (in this case cyano) will take advantage of this. So this simple idea of opportunist competition between bacteria would explain why cyano can out compete others. But, is it to much carbon? Very good question, is it just providing a food source for cyano and not the other bacteria? Honestly I would have to do more research on this. I hope this helps with the discussion. Thanks.