Annual Variation of Weather-induced Hypoxia Events in Callander Bay, Lake Nipissing Canada

Session: Poster session

Robyn Jones, Nipissing University, [email protected]
Dan Walters, Nipissing University, [email protected]
April James, Nipissing University, [email protected]

Abstract

Despite the importance of weather related lake ecosystem changes, little is known about  the annual variation. We used a data buoy to collect ten minute interval weather (pcp., wind sp., air temp.),  water temperature profile (1 m interval) and dissolved oxygen near lake bottom to understand the annual off-ice weather-induced hypoxia events within Callander Bay, Lake Nipissing Canada. Callander Bay is a polymictic, meso-eutrophic embayment located at the eastern side of Lake Nipissing. Occasionally cyanobacteria blooms in embayment can threaten the drinking water supply for the municipality of Callander. Periods of hypoxia can induce internal phosphorus loading that could contribute to occasion blooms.

Does the frequency and magnitude of hypoxia events vary significantly from year to year? We used data from 2013-2017 (June-October) to characterize the variability of hypoxia over this period. We found significant variability. In 2014 and 2015, there were three and twenty periods of hypoxia lasting two days to a two weeks during each event. In 2016 and 2017, there were twentyfour and twentytwo periods of hypoxia, lasting hours to nearly a week. Dissolved phosphorus samples collected at the bed and surface in 2016 and 2017 confirm evidence of internal P loading during these hypoxic events. 

1. Keyword
Buoys

2. Keyword
harmful algal blooms

3. Keyword
oxygen

4. Additional Keyword
hypoxia

5. Additional Keyword
meteorologic conditions

6. Additional Keyword
thermal stability