Cockell and Stokes 2004

Cockell CS, Stokes MD. 2004. Widespread colonization by polar hypoliths. Nature 431: 414.

These authors present a short report about the colonization of the undersides of rocks in the polar deserts by cyanobacteria and unicellular green algae. Where rocks have a protected but accessible underside, these organisms colonize, forming a pale green band a few centimetres across, between the part of the rock too exposed and dry, and too dark for photosynthesis. In polygon terrain, where the ground is sorted by frost heave (“periglacial processes”) and even large rocks are periodically jostled, areas of finer texture form in the centers of polygons, with larger rocks around the edges. The edge rocks were 100% colonized, while central areas were 5% colonized.