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Comment by IdeaHamstir | Hacker News Reader

Azolla = free fish food. It obtains both nitrogen and carbon from the air and can double in mass every 2-3 days. Protein content is 17%. Needs only a few inches of water, sunlight and trace minerals.

I've done the math, and while Azolla can't provide 100% of fish nutrition, it can easily provide the majority of it. It can also provide human food and chickens love it. So do pretty much any domesticated animal: many papers have been written about studies on azolla raised hogs, ducks and cows.

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Maybe not human food - it may contain a neurotoxin. So not good for long-term consumption. Let the fish/chickens digest it first!

Good to know about the possible neurotoxin. Any suggestions for further information on the topic?

Wikipedia?

Been there, done that and have read dozens of research papers on azolla as livestock feed, but there hadn't been any human research when I delved into the subject. That was quite a few years ago, however. I'll dig back into the stacks and see what I find. My chickens prefer azolla over just about anything, I need to grow more of it.

BMAA is the neurotoxin (implicated in Alzheimers and Parkinsons). It also bioaccumulates over time, and potentially up trophic levels. So definitely not fish wonder food until there's some serious testing done.

Thank you. I will definitely look into this. At the very least, it still makes an effective and fairly high nitrogen organic fertilizer, while drawing down atmospheric CO2. It's so effective at harvesting CO2, ancient azolla sequestered sufficient CO2 (from 3500 ppm down to 650 ppm) to create a global ice age: https://en.wikipedia.org/wiki/Azolla_event

Edit: researchers are still studying the issue, but it seems some plants may be capable of concentrating BMAA, which is highly water soluble. Wheat seems to capture it in proteins of the shoots. I haven't found any further specifics other than cycads, which have a cyanobacteria symbiosis and concentrate it in their seed coatings.

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