Cyanobacterial Tintenstrich Communities and their Ecology

Tintenstrich   communities receive their name from the black strips on rocks, which are particularly spectacular on the background of white limestone and dolomite. They are dominated by cyanobacteria, green photosynthesizing procaryotes. However, cyanobacterial crusts are ubiquitous and much more widespread. On bare substratum on walls and rocks in temperate, arid, and tropical zones they are subject to severe stress by insolation, heat, and either too little or too much water. An array of ecophysiological traits allow them to endure this multifactorial stress. Particular features of their photosynthetic membranes may facilitate dissipation of surplus photosynthetically active radiation; special sun-screen pigments protect them from UV radiation, they are desiccation tolerant, concentrate inorganic carbon for photosynthetic fixation, and assimilate atmospheric dinitrogen. With their own success on bare substratum they become pioneers for other organisms.