Milena Frieden

Likened Lichen Patterns

The appearance of a seamless flow of lichens is actually a serendipitous mix of random lichen photos. Lichens have always fascinated me. Their patterns and shapes resemble aerial photos of land and waterscapes or geographical maps. These inconspicuous organisms are sensitive and beautiful, yet strong and persevering.

Lichens are a symbiotic combination of fungus and alga and/or cyanobacterium. It is thought that lichens originally formed as a way for each individual organism to increase its likelihood of survival. It is an excellent example of the whole being greater than the sum of its parts.

The map lichen (Rhizocarpon geographicum), pictured above, grows in mountainous regions and is an indicator of low pollution. Lichens, in general, readily absorb heavy metals in the atmosphere, so they are often used as pollution monitors. Climatologists use map lichen to determine the age of glacial moraine surfaces. Looking at the largest lichen and knowing its growth rate determines how long a stone has been exposed. This technique is known as lichenometry.

Lichens also contribute to biological weathering, which is the process of the lichen gradually breaking down the stone surface it is adhered to. The combination of the broken down stone and the decomposition of the lichens themselves results in the creation of primitive soils, nature’s circular economy.