The tufa spring of Coity Tip

I've been aware of these little features for a while but not taken the time to dig that little bit deeper. Tufa springs are calcium rich seepages, often, as you would expect, present where calcareous rock predominate, but they can also be found leaching at the base of colliery spoil tips. An article in Field Bryology (No 112 Nov 14) suggest a habitat that is dominated by mosses. 

This particular seepage can be found, if you are willing to take a detour from the well worn footpaths, behind Coity Tip, Blaenavon. The calcium rich deposits are distributed over an area of little over 10 square metres, eventually disappearing into a small patch of willow scrub terminating in a base of tip drainage ditch.

I am certainly no bryologist, although I would like to build more of a knowledge around those found on post industrial sites, so I've not been able to compile a list of mosses associated with this seepage beyond just a couple of species. Where the leachate disperses under a stand of willow there is a large patch of the common woodland type moss common smoothcap (Atrichum undulatum) surrounded by flourishing hemlock water dropwort. Here to is a southern marsh orchid pushing its way through the crusty hard baked surface. A rusty dipping tube, presumably in place to monitor coal tip related hydrology, supported a young brood of great tit.

I know there are more of these water based chemical anomalies in the landscape I frequent. I will ensure they are brought to you in future postings.