Joshua Stone

Date of Award


Document Type



Chemistry and Biochemistry


Limestone streams are common in south-central Pennsylvania and arise from aquifers flowing through the abundant limestone (CaCO3) geography of the area. This action imbues the streams with several unique chemical characteristics, leading to a unique ecosystem that is occupied by very different flora and fauna from non-limestone streams in the same area. While calcium carbonate is not easily dissolved, travel through the limestone aquifer significantly changes the chemistry of the water. Limestone streams are characterized by an alkaline pH (7.0 - 8.0), ample plant nutrients, a stable and low temperature, and a relatively constant flow throughout the year (Berrie 1992). Due to their high dissolved oxygen content, these streams of south-central Pennsylvania are world-renowned as trout-fishing streams. Also, their historical significance as sights of watercress (Nasturtium officinale) farming makes them important subjects of research.