Characterizing water quality, nutrients, and dissolved oxygen dynamics in four Lake Ontario coastal wetlands

Great Lakes coastal wetlands are “keystone” ecosystems, yet their role in regulating nutrient loadings to receiving waters remains unclear. Over a decade of monitoring by the Toronto and Region Conservation Authority revealed that four wetlands (Rouge Marsh, Duffin’s Marsh, Carruthers Marsh, and Frenchman’s Bay) vary as net sinks or sources of phosphorus to Lake Ontario. This thesis aimed to improve our understanding of phosphorus dynamics in these wetlands. Continuous multiparameter sondes (dissolved oxygen, conductivity, turbidity, pH) were deployed above sediments, collecting data every 30 minutes, accompanied by weekly water samples. Key findings include a shift in algal (chlorophyll a) nutrient limitation from nitrogen in 2022 to phosphorus in 2023, significant temporal and site-specific variations in anoxic event frequency and duration, and the discovery that bioavailable phosphorus (dissolved phosphorus) is not strongly linked to anoxia or internal loading. These results highlight the complexity of phosphorus cycling in these ecosystems.

Name thesis:degree_name

Master of Science (MSc)

Discipline thesis:degree_discipline

Applied Bioscience

Grantor

University of Ontario Institute of Technology

Year dc:date.issued

2024

Author dc:creator

• Dell’Aquila, Michele

Advisor dc:contributor.advisor

• Kirkwood, Andrea

Language dc:language.iso

en

Handle dc:identifier.uri

https://hdl.handle.net/10155/1893

OAI identifier oai:identifier

oai:ontariotechu.scholaris.ca:10155/1893