An Investigation of Epiphytic Diatom Substrate Specificity and Its Use in Paleolimnology
Abstract
Submerged macrophyte communities are an important component of lake ecosystems that can be altered by anthropogenic disturbances. In the absence of direct monitoring, it is difficult to know how these communities respond to such disturbance. This thesis investigated the potential of epiphytic diatoms preserved in lake sediments to record submerged macrophyte community composition. Epiphytic diatoms from Chara sp., Myriophyllum spicatum and Potamogeton robbinsii were sampled from Gilmour Bay, Ontario, Canada to assess whether submerged macrophyte species were characterized by distinct diatom communities. Principal components analysis indicated overlap, but analysis of similarity suggested there were differences in diatom community composition. A tool was developed and applied to Gilmour Bay nearshore sediment samples to reconstruct past submerged macrophyte community composition, but reconstruction was hindered by abundant in situ epipelic and epipsammic diatoms. This research shows that differences in epiphytic diatom communities offer new opportunities for paleolimnological reconstructions.