CYANOBACTERIAL TINTENSTRICH COMMUNITIES AND THEIR ECOLOGY

Tintenstrich communities receive their name from the black strips on r ocks, which are particularly spectacular on the background of white li mestone and dolomite, They are dominated by cyanobacteria. green photo synthesizing procaryotes. However, cyanobacterial crusts are ubiquitou s and much more widespread. On bare substratum on walls and rocks in t emperate, arid, and tropical zones they are subject to severe stress b y insolation, heat, and either too little or too much water. An array of ecophysiological traits allow them to endure this multifactorial st ress. Particular features of their photosynthetic membranes may facili tate dissipation of surplus photosynthetically active radiation; speci al sunscreen pigments protect them from UV radiation, they are desicca tion tolerant, concentrate inorganic carbon for photosynthetic fixatio n, and assimilate atmospheric dinitrogen. With their own success on ba re substratum they become pioneers for other organisms.