 |
Caroline JohnstonePhD Research StudentBSc (Hons) - University of Stirling (2000) Supervisors: Start Date: 1st October 2005 tel: +44 1786
467831 |
Funded by: |
Member of: |
Current Research
I am examining changes in dissolved organic carbon concentration in UK upland waters. The main objective of this research is to look at what is driving a 60%---90% increase in Dissolved Organic Carbon (DOC) concentration over the last 20 years.
Research Project
Background
A large body of evidence has been gathered over the last two decades which reports an increase in Dissolved Organic Carbon (DOC) concentrations in UK upland waters. On average concentrations of DOC recorded in UK upland waters has risen by 0.18 mg L -1 yr -1 from 1988-2001. Dissolved organic matter is defined as all organic material smaller than 0.45 µm and comprises of a multitude of dissolved compounds derived from organic materials such as decomposed plants and animals. Plant derived compounds known as tannins, lignins and flavonoids are normally referred to as humic substances and have been shown to cause discolouration of water.
Discolouration profoundly affects a streams aesthetic quality. This issue is especially important if an affected stream forms part of the drinking water supply network. Affected waters need treated with higher levels of chlorine (chlorination). Another major concern associated with the increase in DOC is the possible destabilisation of the carbon store. In the UK, 50% of terrestrial carbon is held in Scottish peat. If this store is mobilised it could eventually contribute CO2 to the atmosphere, adding to an already spiraling problem with implication for global warming and climate change.
Study Sites
I have two study sites, one moorland site and one forest site.
Forest site Duchray Water Loch Ard Forest Aberfoyle
Moorland Site at Comer Farm Aberdfoyle head waters of the Duchray
Hypothesis
As SO42- concentration decreases, DOC concentration increases.
This could be explained by the increase in pH associated with an decrease in SO42-. DOC is known to be more soluble at a higher pH. Between 50-75% of DOC is comprised of humic acids and fulvic acids. Fulvic acids are soluble at low pH, however the humic acid fraction is not soluble in water under acidic conditions i.e. (pH <2). Therefore under acidic conditions there would be less DOC in the stream.
Historic data from the Comer Farm site covering the past 20 years including DOC, stream flow and sulphate concentrations have shown that there is an inverse relationship between DOC concentration and sulphate concentration. I have continued to sample at this site and at the Loch Ard site to examine this relationship further, and to compare the results from forest and moorland sites. I have endeavoured to support this hypothesis with a series of targeted laboratory experiments, looking at the effect of changing sulphate concentrations on DOC release from soil cores sampled from both study sites.
Previous projects
1. Mud flat sediments River Forth and Shelduck nesting sites 1999-2000
2. Ecology field experiment Kenya in Africa 2000 (Key experience ecological field work and data analysis).
3. Cloning SIX5 the gene associated with Myotonic Dystrophy. Glasgow 2000-2001
4. The study of the protein translated form MECP2, the gene associated with Rett syndrome. Glasgow 2000-2001 (Key experience gained: protein, DNA and RNA isolation, SDS-PAGE, Western blot analysis using antibodies and a chemiluminescent system. Practical molecular genetics research experience from The University or Glasgow)
5. Analysis of protein samples using a MALDI ToF Mass- Spectrometer, in gel tryptic digests 2D gel electrophoresis, operating a 2D gel spot picking robot, bioinformatics data base analysis using MS fingerprint data, (Key experience Proteomics and Bioinformatics research experience from working in The Proteomics Facility at Edinburgh University)
Outside Interests
Family, Friends
Food (chocolate) and skiing
