The State of Lake Simcoe (Ontario, Canada): The Effects of Multiple Stressors on Phosphorus and Oxygen Dynamics

dc.contributor.authorNorth, R. L.
dc.contributor.authorBarton, D.
dc.contributor.authorCrowe, A. S.
dc.contributor.authorDillon, P. J.
dc.contributor.authorDolson, R. M. L.
dc.contributor.authorEvans, D. O.
dc.contributor.authorGinn, B. K.
dc.contributor.authorHakanson, L.
dc.contributor.authorHawryshyn, H.
dc.contributor.authorJarjanazi, H.
dc.contributor.authorKing, J. W.
dc.contributor.authorLa Rose, J. K. L.
dc.contributor.authorLeon, L.
dc.contributor.authorLewis, C. F. M.
dc.contributor.authorLiddle, G. E.
dc.contributor.authorLin, Z. H.
dc.contributor.authorLongstaffe, F. J.
dc.contributor.authorMacdonald, R. A.
dc.contributor.authorMolot, L.
dc.contributor.authorOzersky, T.
dc.contributor.authorPalmer, M. E.
dc.contributor.authorQuinlan, R.
dc.contributor.authorRennie, M. D.
dc.contributor.authorRobillard, M. M.
dc.contributor.authorRode, D.
dc.contributor.authorRuhland, K. M.
dc.contributor.authorSchwalb, Astrid Nadine
dc.contributor.authorSmol, J. P.
dc.contributor.authorStainsby, E.
dc.contributor.authorTrumpickas, J. J.
dc.contributor.authorWinter, J. G.
dc.contributor.authorYoung, J. D.
dc.description.abstractLake 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 (O2) 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 O2 L(-1). Low deep water O2 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.
dc.format.extent24 pages
dc.format.medium1 file (.pdf)
dc.identifier.citationR.L. North, D. Barton, A.S. Crowe, P.J. Dillon, R.M.L. Dolson, D.O. Evans, B.K. Ginn, L. Håkanson, J. Hawryshyn, H. Jarjanazi, J.W. King, J.K.L La Rose, L. León, C.F.M. Lewis, G.E. Liddle, Z.H. Lin, F.J Longstaffe, R.A. Macdonald, L. Molot, T. Ozersky, M.E. Palmer, R. Quinlan, M.D. Rennie, M.M. Robillard, D. Rodé, K.M. Rühland, A. Schwalb, J.P. Smol, E. Stainsby, J.J. Trumpickas, J.G. Winter & J.D. Young. (2017). The state of Lake Simcoe (Ontario, Canada): The effects of multiple stressors on phosphorus and oxygen dynamics. Inland Waters, 3(1), pp. 51-74.
dc.publisherInternational Society of Limnology
dc.rights.holder© 2013 Her Majesty the Queen in Right of Canada, as represented by Environment Canada
dc.sourceInland Waters, 2013, Vol. 3, No. 1, pp. 51-74.
dc.subjectcoldwater fishery
dc.subjecthypolimnetic oxygen
dc.subjectnearshore shunt hypothesis
dc.titleThe State of Lake Simcoe (Ontario, Canada): The Effects of Multiple Stressors on Phosphorus and Oxygen Dynamics


Original bundle

Now showing 1 - 1 of 1
Thumbnail Image
North et al. 2013.pdf
3.66 MB
Adobe Portable Document Format

License bundle

Now showing 1 - 1 of 1
No Thumbnail Available
2.46 KB
Item-specific license agreed upon to submission