Investigating nutrient dynamics in greenhouse retention ponds in southern Ontario

Session: Poster Session

Emily Varga, University of Windsor, [email protected]
Chris Weisener, University of Windsor, [email protected]
Scott Mundle, Great Lakes Inst. for Environmental Research, [email protected]
Timothy Maguire, Great Lakes Institute for Environmental Research, University of Windsor, [email protected]

Abstract

In 2014, the ‘Canada-Ontario Agreement on Great Lakes Water Quality and Ecosystem Health’ was renewed with an ongoing focus to reduce the amount of phosphorus entering the Great Lakes watershed.  Strong attention has been placed on the Ontario greenhouse sector to ensure that they meet prescribed target values for acceptable levels of phosphorus contained within their retention ponds.  However, some of these values exceed concentration thresholds, despite operators’ attempts to minimize the risks to the environment and responsibly handle their excess nutrient water.  Previous studies of the sediment-water interface of water bodies have shown that sediments can behave as either a source or a sink for phosphorus.  This can be affected by chemical, physical and biological processes.  The biological processes are strongly attributed to the microbial community within the sediment, as it has a strong effect on redox conditions, as well as how nutrients are assimilated or modified.  Here we will investigate the physical, chemical and biological processes of a representative subset of the greenhouse retention ponds thought to be potential nutrient sources.  Research presented focuses on the microbial community dynamics (amplicon sequencing) along with chemical signatures (e.g. stable isotope fingerprints) associated with several ponds influenced by external nutrient stressors.