Spatial and temporal variation in sediment-associated microbial respiration in oil sands mine-affected wetlands of north-eastern Alberta, Canada
Costa, J. M.. 2010. M.S. Thesis Department of Biological Sciences. University of Windsor
Abstract
We measured whether carbon loss in the form of sediment-associated microbial
respiration differed between unvegetated sediments of recently constructed oil sands
process-affected (OSPM) and reference wetlands. Constituents of OSPM-wetlands
(increased salinity, conductivity) were expected to influence respiration, increasing gas
(methane and carbon dioxide) flux and sediment oxygen demands (SOD) compared to
reference wetlands. However,OSPM-wetlands released 1/10th
the methane of reference
wetland sediments but did not differ in CO2 ebulition. Sediment oxygen demand (SOD)
rates were twofold higher in OSPM than reference wetlands; chemical SOD exceeded
biological SOD for both wetland classes (~90% of total SOD). OSPM-wetland
sediments, likely have less microbial activity and more chemical oxidation than reference
wetlands. Carbon accrual is necessary for reclaiming Alberta boreal wetlands. Low
microbial activity may promote carbon sequestration within OSPM-wetlands but high
chemical SOD may limit available oxygen for benthos respiration.
