uu.seUppsala University Publications
Change search
ReferencesLink to record
Permanent link

Direct link
The state of Lake Simcoe (Ontario, Canada): the effects of multiple stressors on phosphorus and oxygen dynamics
Show others and affiliations
2013 (English)In: Inland Waters, ISSN 2044-2041, Vol. 3, no 1, 51-74 p.Article in journal (Refereed) Published
Abstract [en]

Lake Simcoe, the largest lake in southern Ontario outside of the Laurentian Great Lakes, is affected by numerous stressors including eutrophication resulting from total phosphorus (TP) loading, climate change, and invasions of exotic species. We synthesized the long-term responses of Lake Simcoe to these stressors by assessing trends in water quality and biological composition over multiple trophic levels. Evidence for climate change included increasing thermal stability of the lake and changes in subfossil diatom communities over time. Although the deep water dissolved oxygen (O-2) minimum has increased significantly since TP load reductions, it is still below estimated historical values and the Lake Simcoe Protection Plan end-of-summer target level of 7 mg O-2 L-1. Low deep water O-2 concentrations corresponded with a decline in coldwater fish abundance. Since 1980, some nutrient concentrations have decreased (spring TP) while others have increased (silica), but many show no obvious changes (ice-free TP, nitrate, ammonium). Increases in water clarity, combined with declines in chlorophyll a and phytoplankton biovolumes in Cook's Bay, were temporally consistent with declines in TP loading and the lake-wide establishment of dreissenid mussels as a major component of the Lake Simcoe ecosystem. Using an investigative tool, we identified 2 periods when abrupt shifts potentially occurred in multiple parameters: 1986 and 1995-1997. Additional ecosystem level changes such as declines in zooplankton, declines in offshore benthic invertebrate abundance, and increased nearshore invertebrate abundance likely reflect the effects of invasive species. The interaction of these multiple stressors have significantly altered the Lake Simcoe ecosystem.

Place, publisher, year, edition, pages
2013. Vol. 3, no 1, 51-74 p.
Keyword [en]
coldwater fishery, dreissenids, eutrophication, groundwater, hypolimnetic oxygen, nearshore shunt hypothesis, paleolimnology, phosphorus
National Category
Natural Sciences
URN: urn:nbn:se:uu:diva-201303DOI: 10.5268/IW-3.1.529ISI: 000318267100006OAI: oai:DiVA.org:uu-201303DiVA: diva2:626790
Available from: 2013-06-10 Created: 2013-06-10 Last updated: 2013-06-10Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full texthttps://www.fba.org.uk/journals/index.php/IW/article/viewFile/529/338

Search in DiVA

By author/editor
Håkanson, Lars
By organisation
LUVALDepartment of Earth Sciences
Natural Sciences

Search outside of DiVA

GoogleGoogle Scholar
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Altmetric score

Total: 234 hits
ReferencesLink to record
Permanent link

Direct link