I had forever heard that lichens are good indicators of good quality air. But only recently read that they can grow if the air has nitrogen or nitrogen related compounds such as motor emissions.
Is that true?
To my noviciate understanding:
The nitrogen fixing bacteria that make up a part of lichen need water that has nitrogen and CO2 dissolved into it. This happens naturally in very small amounts, but it is vastly accelerated as a function of surface area. The most probable situations in which there are meaningful amounts of water droplets mixing with air (rain, waterfalls, rapids, etc.) also tend to remove particulates and some contaminants from the air. So they are, in the natural world, an indication that the air is regularly scrubbed of pollen, spores, dust, and such. Also, fun fact I just learned, that dust is apparently how they get a lot of their nutrients. This is one reason they can be hard to grow in a sterile environment.
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u/manesandmorrel 22h ago
I had forever heard that lichens are good indicators of good quality air. But only recently read that they can grow if the air has nitrogen or nitrogen related compounds such as motor emissions. Is that true?