2023 Early Hearing Detection & Intervention Conference
March 5-7, 2023 • Cincinnati, OH
6/08/2017 | 9:15 AM - 9:30 AM | USING LAKE LANDSCAPE POSITION TO ASSESS SPATIAL PATTERNS OF BIOTIC MERCURY CONCENTRATIONS ACROSS A FRESHWATER DRAINAGE BASIN IN NORTHERN ONTARIO, CANADA | 301B
USING LAKE LANDSCAPE POSITION TO ASSESS SPATIAL PATTERNS OF BIOTIC MERCURY CONCENTRATIONS ACROSS A FRESHWATER DRAINAGE BASIN IN NORTHERN ONTARIO, CANADA
Within a drainage basin, the position of a lake greatly affects its physical and chemical characteristics many of which have been shown to affect the cycling of mercury (Hg), a neurotoxic metal found in freshwater ecosystems worldwide. In this study, we examined how aqueous and biotic Hg concentrations ([Hg]) varied across lakes and river sites within a large, pristine, subarctic drainage basin in northern Ontario, Canada, relative to their landscape position and associated physicochemical characteristics. A principal component analysis showed that, relative to systems downstream, headwater lakes had lower ion, nutrient, and dissolved organic carbon concentrations, but similar pH. These headwater lakes also had lower total [Hg] in surface waters and forage fish (linear mixed effect models, p<0.01 and 0.03, respectively), as well as lower [MeHg] in pelagic (p<0.001), but not benthic (p = 0.39-0.98), invertebrates. Data analyses, including multiple regression models to assess which physicochemical parameters best explain these longitudinal changes in [Hg], are ongoing. Understanding the physicochemical drivers of Hg cycling in northern Ontario is particularly important given the extensive mining development expected over the next decade.
- C25 Food Webs
- C10 Biogeochemistry
- S16 Understanding and mitigating change in freshwater ecosystem services
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Presenters/Authors
Gretchen Lescord
(), Laurentian University, glescord@laurentian.ca;
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John Gunn
(), Laurentian University, jgunn@laurentian.ca;
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Tom Johnston
(), Ministry of Natural Resources and Forestry, tjohnston@laurentian.ca;
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Brian Branfireun
(), Western University, bbranfir@uwo.ca;
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