CGRG Bibliography of Canadian Geomorphology
Search Results
Author : Das, B.; Nordin, R.; and Mazumder, A.
Date : 2006.
Title : Increased ecosystem variability following impoundment and land-use changes: evidence from sediment geochemical records.
Publication : 59th Canadian Conference for Fisheries Research. 5-7 January 2006, Calgary, Alberta.
Issue :
Page(s) :
Abstract
Although stable isotopes (d13C and d15N) and biogenic silica (BSiO2) have been used for many years as proxy indicators of paleoproductivity in lake sediments, none of them have been employed in order to reconstruct productivity changes due to water level changes in drinking water reservoirs. We explored the use of d13C, d15N and BSiO2 as paleoproductivity indicators in sediments from Sooke Reservoir located in Vancouver Island, British Columbia, Canada. Sediment core trace metal concentrations (Al, As, Ba, Ca, Cd, Co, Cr, Cu, Fe, Mn, Mo, Ni, Pb, Se, Na, V and Zn) were also compared to detect anthropogenic inputs with contrasting land-use activities. The d13C and d15N as well as BSiO2stratigraphy showed a clear isotopic enrichment following impoundments. In comparison, sediment records in Shawnigan Lake, a nearby lake with similar limnological regime but with contrasting land-use activities, also shows an enrichment of isotopic signatures in post-disturbance periods. It seems likely that both types of anthropogenic disturbances (regulated water-level and land-use changes) have had similar impact on lake productivity reconstructed from stable isotope signatures. In contrast, higher sediment accumulation rate resulting in higher trace metal accumulation following impoundments compared to land-use changes. Results from current study can help to better assess trophic history and trace metal accumulation in lake and reservoir systems that have been affected by elevated loadings due to frequent water-level and land-use changes
Bibliography of Canadian Geomorphology