Are Pond Algae Blooms Dangerous?

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It’s impossible these days to go through an entire summer without hearing of some warning about a pond with algae in it.  Often the title might say something like “Toxic Algae Found In Lake” or something similar.

Just this week two new articles came out, one from Kansas, and one from Long Island New York, with warnings that people, pets, and livestock should avoid ponds that are covered with green algae, or if the water is tinted green (blue-green, bown, and even red.)  In the New York case, a pet died after drinking from the pond.

So the question came up about just how dangerous any pond with algae might be and what to watch out for concerning the “toxic outbreaks” that always seem to make the news.

You might recall an article I wrote a year or two ago about this very subject.  You can read that one here.  My attempt in that installment was to try and ease concerns a little bit but in doing so, I don’t want to minimize this issue either.

In that article I mentioned that certainly not every algae bloom will be toxic, and in fact most are not.  The problem comes from that fact that you can’t always tell just how much of a problem an algae outbreak will be.

Visually, with the naked eye, there is simply no way to tell if an algae blooms is, or will become toxic.  Cyanobacteria is a common blue-green algae that produces a toxin called Microcystin.  If you’d like to read up on some technical data surrounding these blooms, their affects and toxicity levels this is a good report out of California.  In it you’ll see that pets, livestock, and wildlife including birds and fish (and we would assume mammals) have been affected, but no human deaths have been recorded.

Usually the ingestion of this bacteria will cause issues with the liver, but along with this, if you come in contact with the algae it’s a good idea to get cleaned up well afterwards to avoid any skin related issues.

So in the end, what can you do about this problem?

Well first, if the algae is present, or I should say any algae that’s tinting the water some color is present, then it would be best to avoid the pond just as a precaution.  Don’t let your pets or livestock drink out of them if possible.  Don’t swim in it or if you do, be sure to get cleaned up as soon as possible after getting out of the water.  To be honest, the way some of these green water algae look, I don’t think you’d be swimming in it by choice anyway but I’ll throw that caution out there.

Watch and listen for advisories in your area, usually from a university or extension service who might issue warnings on toxic algae blooms.  Conditions usually have to be ripe for such things which means you’ll often be dealing with the heat of summer, long sunny days, and of course, the prevailing things that help algae grow in the first place.

And this leads us to one thing that may be helpful in limiting the exposure to this kind of algae.  Remember, although it’s considered a toxin producing species, Cyanobacteria is affected by the same things that all algae is.  It will thrive when nutrients are high in the water, and it will drop in density and concentration when those same nutrients are reduced.

The best way to do this is through the routine use of a high quality beneficial bacteria, coupled with a good form of pond aeration.  These two things will often help keep a pond cleaner.  Ultrasonic algae control might also be incorporated and it works on many types of blue-green algae.  And of course, if necessary, an algaecide may be warranted for use if other more holistic measures don’t clear up the problematic blooms.

The main message I guess is that you and I are not defenseless.  By using a bit of common sense when it comes to limiting exposure to blue-green algae blooms, and working through various control options, these potentially toxic algae outbreaks don’t need to be a cause for great alarm.  

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