Radical Lichenology

I’ve talked about lichens before in a post about viruses, lichens, and slime molds, all things that don't easily fit into the usual biological categories. The easiest thing to say about lichens is that, although they aren't a single species, they act as if they are.  What lichens really are is a relationship.

In the book, Radical Mycology, which I’ve referenced in the last two posts,  there is a chapter on lichens called, naturally, Radical Lichenology.  It's written by Nastassja Noell, who apparently has a degree in Lichenology from Evergreen State College in Olympia, Washington. She defines lichens as being at least “a symbiotic relationship between a fungus and algae and/or photosynthesizing cyanobacteria.”  She goes on to point out that a lichen often contains more than that--sometimes including many other microbes and even fungi, becoming a “miniature ecosystem.”

According to her, there are three ways of looking at lichens.   The first is the ‘Reductionist Perspective’, seeing a lichen as just a fungus and a photosynthesizer working together.  The second is what she calls the ‘Mycocentric Perspective’, seeing the fungus as being in charge and treating the algae as if it were a plant that the fungus is raising.  The third is the ‘Systems Perspective’, where the lichen is an ‘emergent property’, an ecosystem that includes all the living things that make up a lichen, as well as the light, and temperature, and gas levels, and nutrients involved.

Lichens grow very slowly, at the rate of perhaps a millimeter a year, but some of them last for thousands of years.  In dry times, they can go into a dormant, desiccated state in which they can survive for more than a hundred years only to revive when rehydrated. However, they are very sensitive to pollution, so much so that they can be used as indicators of the environmental health of an area.

The chapter contains a lot more about lichens, how to harvest them, how to cultivate them, and how to use them for food and medicine, but what interested me was the fascinating relationships involved in a lichen as well as the systems perspective  that Nastassja Noell takes in looking at lichens and talking about them.

Quote of the day: “Lichens are expressions of pure joy.  … Inside the ecosystem of a lichen are most of the primary components of life: fungi, bacteria, algae, and cyanobacteria, all living in a discrete synergistic system that can rarely be synthesized in vitro but can withstand the extreme conditions of outer space….  The fungal symbiont creates a thick protective skin around the algae to protect it from desiccation.  In exchange, the algae gives the fungus photosynthesized sugars. And together, they form shapes and pigments that help them survive and thrive in their other-worldly surroundings.” - Nastassja Noell