Geograph - photograph every grid square

These rounded structures were present in abundance in some puddles; the area where the puddles occurred corresponds to the snow-covered foreground area of the following photo: NS3977 : Former site of walled garden of Strathleven House.

The blobs in this photo clearly show some variation in size, but the largest are about a centimetre across. They are colonies of cyanobacteria (which used to be referred to as "blue-green algae"); unusually for bacteria, cyanobacteria perform photosynthesis, although the structures involved are not bound within chloroplasts as they are in plant cells.

The species shown here is Nostoc pruniforme, and the blobs are sometimes referred to as Mare's Eggs. NS4377 : Cyanobacteria - Nostoc pruniforme shows some less typical-looking colonies, but provides more details on this species, and on Nostoc in general.

Of interest is the fact that the derelict area where the present photo was taken is rich in fragments of concrete, while the alternative photograph (link just cited) shows colonies growing on limestone, suggesting that these cyanobacteria prefer a lime-rich habitat; this is indeed the case. The concrete fragments here provide an environment that resembles natural limestone sufficiently closely to allow the colonies to flourish.

Although this species was abundant in puddles in this area, the ground nearby was covered in an even greater abundance of another Nostoc species: NS3977 : Cyanobacteria - Nostoc commune.