| Description : Climate change is the greatest environmental threat of our
time. It makes itself felt both regionally and globally through changes in temperature, precipitation and wind patterns.
Air quality research is an important part of climate research. For this issue, Terhi Tuominen and Jitan Patel
chose an usnea, a root‐like bearded lichen, as the coin motif. It functions as a natural air quality measuring device.
The lichens that hang from the bark of coniferous and deciduous trees are alternately humid organisms that are able to use
various water sources such as rain, fog, dew and water vapour for their photosynthesis. In a steady‐state equilibrium
between desiccation and rewetting, nutrient uptake and leaching as well as photosynthesis and respiration, lichens interact
with the immediate environment. They do not have any active control mechanisms such as stomata for transpiration reduction
and CO2 uptake or roots and guide vessels for water supply, but exchange resources passively over their entire surface.
During their metabolic activity, they accumulate substances absorbed from the environment into their organic material. This
applies to environmentally harmful substances such as sulphur dioxide, heavy metals or an excess of nitrogen as well as to
carbon dioxide and water resources. By means of the isotope signature of lichens, insights can be gained into CO2 and water
cycles, and with the help of a so‐called lichen mapping, local climate changes can be detected. On the left, in the
form of an arc, is "ILMASTOTUTKIMUS" (climate research) in Finnish and on the right "KLIMATFORSKNING" in Swedish as the
occasion of issue. Below is the year of issue "2022" and to the right the country abbreviation "FI" (Finland), above a
lion (the heraldic animal of Finland) as the mint mark of the Finnish mint Suomen Rahapaja OY in Vantaa. |
