The new academic year has coincided with the requirement for an intensive research project to be undertaken by 3rd year Environmental Geoscience (EGS) students. The group consists of myself, Will Shanks, David Jinks and Alex Taylor. Naturally, we were all curious to discover the topic on which our research would be based and were surprised to discover it was about Tufa-an unfamiliar substance to us.
Tufa is a type of limestone which forms when carbonate minerals precipitate out of ambient temperature water. When alkaline water (pH>7) emerges from underground aquifers, it degases (Loses) CO2 due to the lower CO2 content in the atmosphere. The release of CO2 reduces the acidity of the water (increases the pH) and provides a suitable environment for tufa to precipitate as the solubility of Tufa reduces with less acidity
A quick browse on google and you will find many eye-catching and impressive examples of Tufa deposits, which can sometimes form columns several meters in height. However, the Tufa which we will be investigating is much smaller in scale, with the majority of it being found as crusts on rocks or around vegetation. This leads us to a question: Why is it important?
It could easily be anonymous due to its diminutive appearance, but Tufa is crucial for plant life. Tufa is porous, can store water and acts as a vital habitat in rivers, streams and lakes for a diverse array of plant life (you can even get plant pots made out of tufa-Alan Titchmarsh eat your heart out!). Tufa can also be used as a paleoclimate indicator (a tool to help reconstruct previous climates). In this study, Tufa in Poland was used to reconstruct temperatures from 9500 to 2000 B.P. https://doi.org/10.1016/0033-5894(88)90022-1.
Armed with a developing knowledge of Tufa, we set out on the morning of the 6th October 2020 to undertake a field recce in Clutton, which is 14km south of Bristol. This gave us the chance to look at the site, practice using the Hach Meters (Device which measures water pH, dissolved oxygen content and electrical conductivity), determine where our measuring sites would be and narrow down the ideas on which our study will be based (all in the pouring rain-wonderful!).
We have decided to investigate the level of influence of different factors on Tufa formation. What physical conditions are perfect for Tufa precipitation and how important are biological factors? Over the next week or so our group will be conducting more field work and laboratory analysis to provide us with the data to answer this question.