Molot, Lewis (On sabbatical Jan–Dec 2011)
Areas of Academic Interest
- Photochemical formation of particulate organic carbon in lakes;
- Fe control of cyanobacterial blooms in lakes.
I am part of a small group of applied scientists in the Faculty of Environmental Studies. My interests focus on aquatic systems, specifically lakes and streams. I teach undergraduate and graduate courses in applied ecology, and I am an active member of several professional organizations including the American Geophysical Union and the Canadian Society of Limnologists. Often, I work with graduate students in FES who conduct research examining relationships between science and sustainable development.
I also supervise graduate students pursuing scientific research in the Geography Department. Students with a BSc or MSc interested in pursuing a graduate degree in one of the scientific research projects described below should contact me at lmolot@yorku.ca.
Major research projects
- Regulation of nuisance cyanobacterial relative abundance in freshwaters.
- Organic carbon, iron and phosphorus dynamics in freshwaters including wetland export to lakes and lake retention.
- Effect of ultraviolet radiation A and B on loss of organic carbon in freshwaters.
The presence of cyanobacteria blooms in eutrophic waters is a concern because of the production of potent toxins and taste and odour altering compounds by many strains. Cyanobacterial blooms have long been associated with excessive nutrient loading, prompting the investment of large amounts of money in sewage treatment. In spite of many years of research, the specific mechanisms leading to cyanobacterial dominance are not well understood. My lab is studying whether iron limits growth of cynaobacteria in oligotrophic freshwaters.
I have also been studying the effects of multiple environmental stresses on lakes in central Ontario. The study sites have been the major focus of a long-term environmental monitoring project and have proven extremely useful in studying the effects of cottage development, acidification, climate change, mercury contamination and increasing ultraviolet radiation - all of which can affect the landscape simultaneously. For the past several years, my research has focused on describing the movement of carbon from forested catchments through northern lakes and the effects that UV and acidification have on the storage of carbon in lake sediments and the return of carbon to the atmosphere from lakes. Climate change is controlled to a large degree by the level of carbon in the atmosphere, yet we do not have a clear understanding of how carbon cycles into and out of the atmosphere. My work fills in some of the blanks about the fate of carbon after it is removed from the atmosphere and converted to plant tissue in northern wetlands. I am currently examining how non-biological mechanisms transfer carbon to long-term storage in sediments.
The research has shown that lake carbon is derived in large part from catchments. Sediments in northern lakes in Canada, the U.S., Russia and Scandinavia comprise the second largest global store of carbon on land, nearly as large as the vast peat deposits and more than is stored in trees. We also found that the rate at which carbon is stored in sediments is affected by the rate of stream flow, the degree of acidification and the intensity of ultraviolet radiation.
Other positions/affiliations
- Canada-Ontario Great Lakes Innovation Committee, member of the Monitoring and Issues Team. Ad hoc advisory committee to Canada-Ontario Management Committee.
- 2004/06 Chair, Heart Lake Conservation Area (Toronto Region Conservation Authority) Master Plan Public Advisory Committee.
- 2000/04 Chair, York Environmental Education Consortium consisting of seven school boards and York University. The Consortium initiated and developed the Ontario EcoSchools project, an ecoliteracy project that has developed classroom resource units in environmental science and environmental studies for Ontario Grades 1-12 (18 school boards participating).
Select publications
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. Accepted.
Zhang, J., J. Hudson, R. Neal, T. Clair, M. Turner, D. Jeffries, P.J. Dillon, L.A. Molot, K. Somers and R. Hesslein. 2009. Long-term patterns of dissolved organic carbon in lakes across eastern Canada: evidence of a pronounced climate effect. Accepted.
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: Humic Substances, Accepted.
Molot, L.A., Color of Aquatic Ecosytems. 2009. Chapter 69 In Encyclopedia of Inland Waters, G.E. Likens (editor in chief), Elsevier.
Molot, L.A. and P.J. Dillon. 2008. Long-term trends in catchment export and lake concentrations of major 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(3): 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(1): 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.