sirdarksol

... it could be bunnies.
No.
Wait.
That's not where I was going with this.

No, my theory stems from something I read in the local paper. It seems that a number of lakes in MN have been suffering from particularly bad blue-green algae outbreaks (the dreaded cyanobacteria).
It turns out that there is a link between zebra mussels and cyanobacteria outbreaks. Zebra mussels eat algae by filtering it out of the water, but they won't eat cyanobacteria (at least not the toxic kind that can make both fish and land animals sick). If there's enough zebra mussels, they clear the regular algae out of the water, making the lake sparkling crystal clear. Great, right?
Here's where the problem comes in, that algae was growing because there was an excess of nutrients in the water. That's algae's job, to use those nutrients up and turn them into food for slightly larger critters, like fish fry. Without the algae, cyanobacteria has no competition for the nitrogen or the phosphorous. Worse, without the algae darkening the water, the cyanobacteria (which tends to drape over things, and thus doesn't grow as much on the surface of the water) gets tons and tons of sunlight. The end result; a huge cyanobacteria outbreak.

The same kind of thing can happen in our tanks. If there's an excess of nitrogen and phosphorous (such as would happen if one doesn't keep up with water changes, or if the water supply had an unusually high amount), and if there is a minimal amount of algae (such as would happen if one were to religiously clean the algae from the tank, or if an algae-eating fish were to do so), the potential for a cyanobacteria outbreak grows.

This isn't the whole picture, of course, but it makes a certain amount of sense. The biggest difference between my tank that had cyanobacteria and the rest was that I had a couple of otos in the tank, and it was small enough that they could easily keep it clean.

bolivianbaby

That was my thought when I saw the title of the thread! Go Buffy & angel & everything else Joss Whedon creates!

I couldn't understand the rest of your thread. Earth Science was not my forte

sirdarksol

Put simply, if there is too much nitrogen (ammonia, nitrites, or nitrates all count as nitrogen), and too much phosphorous (common in water supplies... it also enters our tanks in the form of fish food), there is the opportunity for a large amount of either algae or cyanobacteria.
Algae will usually win the battle, but if we stifle the algae's growth and reproduction (by adding plecos or otos, or by cleaning it out, or by adding algaecide), and if the wrong type of cyanobacteria is present in the water, we give the cyanobacteria a chance to take over the tank.

Many types of cyanobacteria are helpful, even necessary, for aquatic systems to function properly. However, a few of them make very toxic chemicals as waste, and can kill fish off if left unchecked.

bolivianbaby

I follow you now. It makes sense. Also gives me a reason to allow a little bit of algae to stay in my tanks

Iron waffle

It really makes you consider the importance of single celled microorganisms. Do they know what's causing it in your local lakes? I know that the nitrogen wastes are produced by other underwater organisms. has there been an overpopulation?

sirdarksol

We have always had a problem with nitrogen and phosphorous in our lakes. It's getting better since the state has banned phosphorous in most lawn fertilizers, but there's still the nitrogen, the runoff of yard waste, and the runoff from our numerous farms.
With zebra mussels (and the even more problematic quagga mussels) spreading to MN inland lakes, there's more and more chance that any given lake has an excess of nutrients without the algae to soak it up.