SS3.14 An Interdisciplinary Journey Towards Integrated Aquatic Sciences: Homage to Jacob Kalff
Date: Thursday, June 13, 2002
Time: 2:30:00 PM
Location: Saanich
 
RooneyN, McGill University, Montreal, Canada, nrooney@bio1.lan.mcgill.ca
Kalff, J, , McGill University, Montreal, Canada, jkalff@bio1.lan.mcgill.ca
 
SEDIMENT AND PHOSPHORUS ACCUMULATION WITHIN AND AMONG SUBMERGED MACROPHYTE BEDS
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Studies have examined sediment accumulation rates (SARs) in different regions of lakes, yet variation in SARs has not been measured within macrophyte stands. In this study, long-term (~115 yr) SARs were measured among sites (11 sites) at the depth of maximum submerged macrophyte biomass and within one site (3 transects perpendicular to the shore yielding 21 cores) in Lake Memphremagog, (Quebec, Canada). Sediment cores were extruded and stable Pb was used to date the sediments. Regression models show that submerged macrophyte biomass (g m-2) is the best predictor of total (mm yr-1), bulk (g m-2 yr-1), and organic (g m-2 yr-1) SARs among and within macrophyte beds. There was no difference between accumulation rates among and within macrophyte beds with respect to macrophyte biomass. Phosphorus SARs (means, 116-238 mg m-2 yr-1) were related to biomass among sites, but less predictable within the macrophyte bed. Results confirm the link between macrophyte biomass and SARs among sites, and provide measurements of variability in SARs within macrophyte beds. Further, long-term phosphorus accumulation in the littoral zone is linked to the presence of macrophytes.