More on danger from cyanobacteria in our ponds. Yes, in some circumstances it even pollutes the air. Interesting!

https://www.upi.com/Science_News/20...bloom-airborne-atx-toxins/6441617366550/

Hopefully Bill Cody will chime in, there are only a few cyanobacterias out there, and they are only toxic after they die. Manage the nutrient loading in the pond and you will never have that problem.

There were two ponds, at the fringes of where I travel to fish that had what I think may have be golden algae blooms last year. Both resulted in fish kills. Now this algae isn't cyanobacteria but can and does produce toxins that have been problematic in Texas particularly. One thing I will say about each of these ponds is that each receives large loads of fertilizer and herbicides. One is fed from tiles underlying many acres of soccer fields, the other is in a public park which receives drain from a large subdivision which had strict rules for lawns which includes the control of nuisance vegetation.

Though blooms of various kinds can happen and might possibly be unpreventable, it might also be that we have much more to learn. Where we humans have smaller impact, these problems are much rarer. Pristine waters tend to have diverse assemblages of algae and blue green algae where all contribute to the greater good of the system. The enemy is less the algae and much more our ignorance and complicity.

Quick bit of research reinforced the role of warm, stagnant, nutrient-rich water in cyanobacteria blooms. Thus, systems that move water & help cool near surface areas should be helpful, as would floating islands that take out excess nutrients. Also, of course, it is smart to see if nutrient load can be reduced at the source(s) in the watershed.

Even with liming & fertilization, I struggle to get a good phytoplankton bloom, but maybe that's not entirely a bad thing as it also means less danger of cyanobacteria bloom. As for the airborne toxin, I remember reading years ago a claim that even walking around a lake infested with blue-green algae could cause amyloid plaque brain changes similar to Alzheimer's, though I haven't seen much on that since then.

PS I wonder if filter feeders like paddlefish or threadfin shad might be useful? Or perhaps vigorous harvest of other fish might help remove some nutrients. Another reason to take out LMB?

6 or 8 144 sq. ft. floating islands wasn't enough to remove enough nutrients from a 3.8 ac pond.(av 9' depth). It had a high nutrient load, getting runoff from a large field for years. Yearly alum treatments has got the cyanobacteria in check now.

I remember reading that floating islands need to cover 4 percent of water surface, on average, to clean up heavy nutrient load. Perhaps alum treatments are a more budget friendly approach.