Faculty Profiles

Lewis Molot

BSc (Zoology) - Toronto
MSc (Limnology) - Toronto
PhD (Oceanography) - Alaska

Areas of Academic Interest

  • Iron promotion of toxic cyanobacterial blooms in freshwaters

  • Role of ultraviolet radiation and visible radiation in freshwater organic carbon processing

  • Role of phosphorus in dissolved oxygen depletion in Lake Simcoe bottom waters

  • Internal loading of phosphorus and iron


I am part of a small group of applied scientists in the Faculty of Environmental Studies. My interests focus on ecological processes and pollution in lakes. Over the years I have studied acidification, carbon processing in lakes (photochemistry) and eutrophication and have developed several management tools (models) to assist environmental managers.

I teach undergraduate and graduate courses in applied ecology. I also supervise graduate students in FES interested in examining relationships between science and sustainable development and graduate students in Biology and Physical Geography involved in projects described below.



Major research projects


  • Phosphorus and ferrous iron co-promotion of toxic cyanobacterial blooms in freshwaters
  • Impact of climate change on oxygen depletion in lakes

Eutrophication (impacts created by excessive inputs of plant nutrients, especially phosphorus, to surface waters) remains an important global issue in spite of the wealth of attention paid to it in the last 50 years. In particular, blooms of algal-like cyanobacteria in eutrophic lakes and rivers are one of the most serious water quality problems in the world because they often produce nerve and liver toxins and chemicals that alter the taste and odour of drinking waters.

My interest in eutrophication is several-fold. First, I am exploring how phosphorus and ferrous iron co-promote blooms of toxic cyanobacteria in eutrophic waters and have developed a new model that explains how cyanobacteria displace their eukaryotic competitors (Molot et al., Freshwater Biology 2014). Second, I am interested in how climate change has affected oxygen concentrations at the sediment/water boundary because this may be key to understanding why bloom formation has become more common in recent decades in systems that have not suffered phosphorus increases. Third, I am developing new environmental management tools (i.e., models and indicators) that will assist environmental managers to predict which lakes are sensitive to blooms and when blooms will begin. Students interested in applying for MSc or PhD studies in my lab should contact me at lmolot@yorku.ca.


Selected Publications

Refereed Journal Articles

Porcal, P., P.J. Dillon and L.A. Molot. 2015. Temperature dependence of photodegradation of dissolved organic matter to dissolved organic matter and particulate organic matter. PLOS One. Accepted.

Schwalb, A., D. Bouffard, L. Boegman, L. Leon, J.G. Winter, L.A. Molot, R.E.H. Smith. 2014. 3D modelling of dreissenid mussel impacts on phytoplankton in a large lake supports the nearshore shunt hypothesis and the importance of wind-driven hydrodynamics. Aquatic Sciences.  DOI 10.1007/s00027-014-0369-0.

Porcal, P., P.J. Dillon and L.A. Molot. 2014. Interaction of extrinsic chemical factors affecting photodegradation of dissolved organic matter in aquatic ecosystems. Photochemical and Photobiological Sciences. 13: 799-812.

Molot, L.A., S.B. Watson, I.F. Creed, C.G. Trick, S.K. McCabe, M.J. Verschoor, R.J. Sorichetti, C. Powe, J.J. Venkiteswaran and S.L. Schiff. 2014. A novel model for cyanobacteria bloom formation: The critical role of anoxia and ferrous iron. Freshwater Biology. 59(6): 1323-1340, DOI 10.1111/fwb.12334.

Oni, S.K., M.N. Futter, L.A. Molot, P.J. Dillon and J. Crossman. 2014. Uncertainty assessments and hydrological implications of climate change in two adjacent agricultural catchments of a rapidly urbanizing watershed.  Science of the Total Environment. 473-474:326-337.

Porcal, P., P.J. Dillon, L.A. Molot. 2013. Seasonal changes in photochemical properties of dissolved organic matter. Biogeosciences. 10: 5533-5543.

Nürnberg, G.K., L.A. Molot, E. O’Connor, H. Jarjanazi, J.G. Winter and J.D. Young. 2013. Evidence for internal phosphorus loading, hypoxia and effects on phytoplankton in partially polymictic Lake Simcoe, Ontario. Journal of Great Lakes Research. 39(2): 259-270.

Nürnberg, G.K., B.D. LaZerte, P.S. Loh, L.A. Molot. 2013. Quantification of internal phosphorus load in large, partially polymictic and mesotrophic Lake Simcoe, Ontario. Journal of Great Lakes Research. 39(2): 271-279.

Porcal, P., P.J. Dillon, L.A. Molot. 2013. Photochemical production and decomposition of particulate organic carbon in a freshwater stream. Aquatic Sciences. 75: 469-482.

Verschoor, M. and L.A. Molot. 2013. A comparison of three colorimetric methods of ferrous and total reactive iron measurement in freshwaters. Limnology and Oceanography: Methods. 11: 113-125.

Loh, P.S., L.A. Molot, G.K. Nurnberg, S.B. Watson and B. Ginn.  2013. P and Fe release rates from anoxic sediments in Lake Simcoe, Lake Winnipeg and Hamilton Harbor and their relationship to sediment fractions. Can release be predicted by sediment fraction chemistry? Inland Waters. 3: 105-118.

North, R.L., D. Barton, A.S. Crowe, P.J. Dillon, R.M.L. Dolson, D.O. Evans, B.K. Ginn, 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 and J.D.Young. 2013. The state of Lake Simcoe (Ontario, Canada): long-term responses to multiple stressors. Inland Waters. 3: 51-74.

Oni, S.K., M.N. Futter, L.A. Molot and P.J. Dillon. 2012. Adjacent catchments with similar patterns of land use and climate have markedly different DOC and runoff dynamics.  Hydrological Processes. 28: 1436-1449.

Oni, S.K., M.N. Futter, L.A. Molot and P.J. Dillon. 2012. Modelling the long term impact of climate change on the carbon budget of Lake Simcoe, Ontario using INCA-C. Science of the Total Environment, 414: 387-403.

Young, J., J. Winter and L.A. Molot. 2011. A re-evaluation of the empirical relationships connecting dissolved oxygen and phosphorus loading after zebra mussel invasion in Lake Simcoe. Journal of Great Lakes Research. 37(Supplement 3): 7-14.

Persaud, A., P.J. Dillon and L.A. Molot. 2011. Relationships between body size and trophic position of consumers in temperate freshwater lakes. Aquatic Sciences. 73:  DOI 10.1007/s00027-011-0212-9.

Koprivnjak, J-F., P.J. Dillon and L.A. Molot. 2010.  Importance of CO2 evasion from small boreal streams. Global Biogeochemical Cycles, 24: GB4003, doi:10.1029/2009GB003723.

Molot, L.A., G. Li, D.L. Findlay and S.B. Watson. 2010. Iron-mediated suppression of cyanobacteria blooms by oxine in a eutrophic lake. Freshwater Biology, 55:1102-1117.

Zhang, J., J. Hudson, R. Neal, T. Clair, M. Turner, D. Jeffries, P.J. Dillon, L.A. Molot, K. Somers and R. Hesslein. 2010. Long-term patterns of dissolved organic carbon in lakes across eastern Canada: evidence of a pronounced climate effect. Limnology and Oceanography. 55:30-42.

Porcal, P., J-F. Koprivnjak, L.A. Molot, and P.J. Dillon. 2009.  The biogeochemistry of dissolved organic carbon and its interactions with climate change.  Environmental Science and Pollution Research International: Humic Substances Part 7. 16(6): 714-726. (invited review)

O’Connor, E.M., P.J. Dillon, L.A. Molot and I.F. Creed. 2009. Modeling regional-scale dissolved organic carbon mass balances for lakes of the Muskoka River Watershed. Hydrology Research 40: 273-290.

Molot, L.A. and P.J. Dillon. 2008. Long-term trends in catchment export and lake concentrations of base cations in the Dorset study area, Central Ontario.  Canadian Journal of Fisheries and Aquatic Sciences 65: 809-820. Dorset Environmental Science Centre special issue.

Kelton, N, L.A. Molot and P.J. Dillon. 2007. Spectrofluorometric properties of dissolved organic carbon from Central and Southern Ontario streams. Water Research. 41: 638-646.

Kelton, N, L.A. Molot and P.J. Dillon. 2007. Effect of ultraviolet and visible radiation on iron lability in boreal and artificial waters. Aquatic Sciences. 69: 86-95.

Medeiros, A.S. and L.A. Molot. 2006. Trends in iron and phosphorus loading to Lake Ontario from waste water treatment plants in Hamilton and Toronto. J. Great Lakes Research, 32: 788-797.

Dillon, P.J. and L.A. Molot.  2005.  Long-term trends in catchment export and lake retention of dissolved organic carbon, dissolved organic nitrogen, total iron and total phosphorus: The Dorset, Ontario study, 1978-1998. Journal of Geophysical Research – Biogeosciences, 110, No.G01002, doi:1029/2004JG000003.

Molot, L.A., J.J. Hudson, P.J. Dillon and S.A. Miller. 2005. Effect of pH on photo-oxidation of dissolved organic carbon by hydroxyl radicals in a coloured, softwater stream. Aquatic Sciences, 67: 189-195.

Molot, L.A., W. Keller, P.R. Leavitt, R.D. Robarts, M.J. Waiser, M.T. Arts, T.A. Clair, R. Pienitz, N.D. Yan, D.K. McNicol, Y. Prairie, P.J. Dillon, M. Macrae, R. Bello, R.N. Nordin, P.J. Curtis, J.P. Smol and M.S.V. Douglas. 2004.  Risk analysis of dissolved organic carbon-mediated UVB exposure in Canadian inland waters. Canadian Journal of Fisheries and Aquatic Sciences, 61:2511-2521.

Macrae, M.L.S., R.L. Bello and L.A. Molot. 2004. Carbon storage and gas exchange in tundra ponds in the Hudson Bay Lowland. Hydrological Processes, 18: 2051-2069.

Creed, I.F. S.E. Sanford, F.D. Beall, L.A. Molot, P.J. Dillon. 2003. Cryptic wetlands: Integrating hidden wetlands into models of dissolved organic carbon export from forested landscapes. Hydrological Processes, 17: 3629-3648.

Dillon, P.J., B.J. Clark, L.A. Molot and H.E. Evans.  2003.  Predicting the location of optimal habitat for lake trout (Salvelinus namaycush Walbaum) in Canadian Shield lakes. Canadian Journal of Fisheries and Aquatic Sciences, 60: 959-970.

Molot, L.A., S.A. Miller, P.J. Dillon and C.G. Trick.  2003. A simple method for assaying extra-cellular hydroxyl radical activity and its application to natural and synthetic waters. Canadian Journal of Fisheries and Aquatic Science, 60: 203-213.

Clark, B.J., P.J. Dillon, L.A. Molot and H.E. Evans.  2001. Application of a hypolimnetic oxygen profile model to lakes in Ontario. Lake and Reservoir Management, 18: 32-43.

Gennings, C., L.A. Molot and P.J. Dillon.  2001. Enhanced photochemical loss of dissolved organic carbon in acidic waters. Biogeochemistry, 52: 339-354.

Book Chapters

Watson, S.B. and L.A. Molot. 2013. Harmful algal blooms. In Encyclopedia of Aquatic Ecotoxicology, J.F. Férard and C. Blaise (eds). Springer, DOI 10.1007/978-94-007-5704-2.

Molot, L.A., Color of Aquatic Ecosytems. 2009. In Encyclopedia of Inland Waters, G.E. Likens (editor), Volume 2, pp. 657-663, (invited), Elsevier,

Clark, B.J., B.J., P. J. Dillon and L.A. Molot.  2004.  Lake trout (Salvelinus namaycush) habitat volumes and boundaries in Canadian Shield lakes. Chapter 6, p.111-118, in Lake Trout Ecosystems in a changing environment, J.M. Gunn, R.J. Steedman and R.A. Ryder [eds.], Lewis Publishers, Boca Raton.