Like a priceless painting, the beautiful blue and green swirl in a lake or pond presents a look-don’t-touch kind of situation. It’s the work of proliferating cyanobacteria, also known as blue-green algae, which produces toxins that are poisonous to humans and other animals, especially when blooms corrupt freshwater supplies. These toxins, which the microbes evolved to deter herbivores, are linked to ALS and Parkinson’s disease, plus muscle paralysis and liver and kidney failure. One of the toxins, anatoxin-a, is known as Very Fast Death Factor, in case you were doubting that toxicity.
It seemed a shame, then, that a highly nutritious fern called Azolla — that green mat ducks eat on ponds — long ago made a pact with a species of cyanobacteria, an “endocyanobiont.” Living inside the fern, the microbes get shelter, and provide the plant with essential nitrogen in return. Lately, scientists have been campaigning to turn the fast-growing Azolla into a food of the future. Others envision it becoming both a sustainable biofuel and a fertilizer that captures carbon. But these ideas aren’t likely to get very far i... Read more
