The characteristic qualities of karst landscape manifest themselves at the surface as well as below ground. Often the surface of the fields and unmade roadways have the appearance of a reticulated network of ‘V ’-shaped grooves, where the rock is fractured and weathered. Small ponds are created through surface erosion and the subsequent presence of algae, which produce carbon dioxide and organic acids. The development of holes in the surface of vertical rocks is due to the acids released by small clumps
of moss and algae which cling to the rock surface. Other organisms that flourish within the first few millimetres of the rock’s structure may also have a similar corrosive effect.