CGRG Bibliography of Canadian Geomorphology
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Author : Cyr,H.; Rider, P.A.; and Lozon, J.
Date : 2002.
Title : Distribution of soft sediment habitats in the littoral zone of lakes on the Canadian Shield.
Publication : 9th International Symposium on the Interactions Between Sediments and Water. International Association for Sediment Water Science (IASWS). Banff Springs Hotel, Canada. May 5 - 10, 2002.
Issue :
Page(s) :
Abstract
The highly productive littoral zone of lakes is notoriously patchy and dynamic. Sediment resuspension models provide clear predictions about the distribution of fine organic particles, which should determine the physical and chemical composition of soft sediments around lake basins, and should set the stage for development of biological communities. We tested these relationships in 2 stratified basins where sediments are mostly resuspended during lake turnover at the beginning of the growing season, and in 2 unstratified basins where random resuspension events occur throughout the ice-free period. We sampled sediments at 6 protected to highly exposed sites around each basin, and measured sediment particle size, porewater and organic content, nutrient content, exopolymeric substances (EPS) and benthic algal biomass. Sediment composition at a 2-3 m depth was closely related to sediment porewater content, but not to fetch, a common measure of site exposure. Total nitrogen (TN), but not phosphorus (TP), was positively related to organic content, resulting in a clear increase in TN:TP ratio with increasing organic, and porewater, content of the sediments. Benthic algal biomass was positively related to sediment porewater content in unstratified basins, but negatively related in stratified basins. Preliminary pigment data suggest a systematic change in the taxonomic composition of algal communities, with relatively more bluegreen algae on sediments with low porewater content. Our results suggest that sediment porewater content is a powerful predictor of the chemical and biological composition of soft sediments in the shallow littoral zone of lakes.
Bibliography of Canadian Geomorphology