科研之友
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摘要
The spatial footprint over which municipal wastewater effluents cause changes to aquatic community structure and metabolism is key information required for the management of discharges into rivers. Longitudinal studies were undertaken on the Bow and South Saskatchewan rivers, Canada, to assess a new isotopic and modelling approach that combined O-2 and delta O-18-O-2 diel (24 h) response curves to quantify changes in integrated community aquatic metabolism as a result of point-source wastewater inputs. Diel samplings were conducted over four seasons along 50 km transects at Calgary (Bow River) and Saskatoon (South Saskatchewan River). Diel O-2 and delta O-18-O-2 cycles grew in magnitude downstream of effluent inputs in all seasons compared with upstream control sites. delta O-18-O-2 depletions clearly revealed the stimulating effect of effluent on aquatic photosynthesis. Diel isotopic mass balance modelling showed community metabolic responses to effluent inputs were most pronounced in the spring and summer when photosynthesis and respiration rates were about two-to three-fold higher than at upstream control sites. Our findings revealed that sewage treatment plant nutrient additions resulted in an enhanced metabolic footprint that extended beyond 50 km downstream.
- 出版日期2010-8
