Template:POTD/2011-06-23

Picture of the day

Mudcracks in sludge, the remains of a sewage treatment plant in Kos, Greece. Mudcracks naturally form when wet, muddy sediment desiccates, causing contraction through a decrease in tensile strength. Individual cracks join up, forming a polygonal, interconnected network. These cracks may later be filled with new sediment, forming casts on the base of the overlying bed.Photo: Hannes Grobe