Sara Hegewald

Increase in Dissolved Organic Carbon: a Palaeolimnological Analysis Sara Hegewald

Over the past two decades, rising concentrations of dissolved organic carbon (DOC) have been observed in many freshwater lakes in Great Britain. Rising levels of DOC have implications for water quality and the carbon and energy balance of a system. Several hypotheses have been suggested to explain recent trends in DOC; however, a recent hypothesis suggests that reductions in acidifying emissions and thus sulphur deposition over the past two decades augmented by a decline in marine ion loading has been the cause behind the recent rise in DOC. In order to test this hypothesis, a palaeolimnological analysis was adopted by applying existing transfer functions produced by SWAP and EDDI to a previously compiled dataset comprising information from 97 cored lakes throughout Great Britain in order to reconstruct past levels of pH and DOC. This was to assess change through time in relation to the level of sulphur deposition at a site and overall, TOC which was used as a surrogate for DOC and pH were found to decline through time. Reliable reconstruction of TOC however, did not take place as both models consistently over and under predicted each value. Model predictive ability was also based