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Home People Stephanie Guildford
Stephanie Guildford

Associate Professor

Large Lakes Observatory
University of Minnesota Duluth
2205 E. 5th St.,
Research Laboratory Building 109
Duluth, MN 55812

Fax: (218) 726-6979

email: sguildfo at


  • Phytoplankton and nutrient dynamics with a focus on the health and productivity of African and North American great lakes.


University of Manitoba, Ph.D.
University of Manitoba, M.Sc.
Dalhousie University, B.Sc.

* denotes student author

Havens, S.M., Hassler, C.S., North, R.L.*, Guildford, S.J., Silsbe, G.S.*, Wilhelm,S.W., and Twiss, M.R. Iron plays a role in nitrate drawdown by phytoplankton in Lake Erie surface waters as observed in lake wide assessments. Can.J.Fish.Aquat.Sci. In Press Jan 2012.

Witte, F., Silsbe, G.M.*, Hecky, R.E., Goudswaard,P.C., Guildford, S.J., Kishe-Machumu, M.A., Wanink, J.H. 2011. Did the loss of phytoplanktivorous fish contribute to algal blooms in the Mwanza Gulf of Lake Victoria? Hydrobiologia DOI 10.1007/s10750-011-0893-z

Poste, A. E.*, Hecky, R.E., Guildford, S.J. 2011. Evaluating microcystin exposure risk through fish consumption. Environ. Sci. & Technol. 45(13) 5806-5811.

Palmer, M.E., Winter, J.G., Young, J.D., Dillon, P.J., Guildford, S.J. 2011. Introduction and summary of research on Lake Simcoe:Research, monitoring, and restoration of a large lake and its watershed.. J. Great. Lakes Res. 37 (Supplement 3), 1-6.

Depew, D. C.*, Houben, A. J.*, Ozersky, T.*, Hecky, R. E., Guildford, S. J. 2011. Submerged aquatic vegetation in Cook's Bay, Lake Simcoe: Assessment of changes in response to increased water transparency. J. Great. Lakes Res. 37 (Supplement 3), 72-82.

Depew, D. C.*, Houben, A. J.*, Ozersky, T.*, Hecky, R. E., Guildford, S. J. 2011. Why does Cladophora fail to reach nuisance proportions in Lake Simcoe? J. Great. Lakes Res. 37 (Supplement 3), 90-102.

Gondwe, M. J.*, Guildford, S. J., Hecky, R. E. 2011. Carbon, nitrogen and phosphorus loadings from tilapia fish cages in Lake Malawi and factors influencing their magnitude. J. Great. Lakes Res. 37 (Supplement 1) 93-101.

Gondwe, M.J.*, S., Guildford, S. J., Hecky, R. E. 2011. Physical-chemical measurements in the water column along a transect through a tilapia cage fish farm in Lake Malawi, Africa. J. Great. Lakes Res. 37 (Supplement 1) 102-113.

Ozersky, T., Barton, D. R., Depew, D. C.*, Hecky, R. E., Guildford, S. J. 2011. Effects of water movement on the distribution of invasive dreissenid mussels in Lake Simcoe, Ontario. J. Great. Lakes Res. 37 (Supplement 3), 46-54.

Leon, L.F.,Smith, R.E.H. , Hipsey, M.R., Bocaniov, D.A., Higgins,S.N.*, Hecky, R.E. 2011. Antenucci, J.P., Guildford, S.J. 2011. Application of a 3D hydrodynamic-biological model for seasonal and spatial dynamics of water quality and phytoplankton in Lake Erie. J. Great Lakes Res. 37 (1) 41-53.

Guildford, S.J. and Taylor W.D. 2011. Evidence supporting the importance of nutrient regeneration by nano- and micrograzers for phytoplankton photosynthesis in Lake Malawi/Nyasa. J. Great. Lakes Res. 37 (Supplement 1) 54-60.

Malkin, S.Y.*, S.A. Bocaniov, R.E. Smith, S.J. Guildford and R.E. Hecky. 2010. In situ measurements confirm the seasonal dominance of benthic algae over phytoplankton in nearhore primary production of a large lake. Freshwater Biology55, 2468-2483.

Malkin, S.*, A. Dove, D. Depew*, R.E. Smith, S.J. Guildford and R.E. Hecky. 2010. Spatio-temporal patterns of water quality in Lake Ontario and their implications for nuisance growth of Cladophora. J. Great Lakes Res. 36, 477-489.

Gikuma Njuru, P.*, Guildford, S.J., Hecky, R.E. 2010. Surficial sediment phosphorus fractions along a biogeochemical gradient in Nyanza (Winam) Gulf, northeastern Lake Victoria and their possible role in phosphorus recycling and internal loading. Biogeochemistry 97 (2-3), 247-261.

Squires, M.M., Lesack, L.F.W., Hecky, R.E., Guildford, S.J., Ramlal, P.A., Higgins, S.N.* 2009. Primary production and carbon dioxide metabolic balance of a lake-rich Arctic river floodplain: Partitioning of phytoplankton, epipelon, macrophyte, and epiphyton production among lakes on the Mackenzie Delta. Ecosystems. 12:853-872.

Gondwe, M.J.*, Guildford, S.J., Hecky, R.E. 2009. Sandy shore benthic N2-fixation in Lake Malawi, Africa. Verh. Internat. Verein. Limnol. 30 (6): 941-944.

Guildford, S.J., Muir, D.C.G., Houde, M., Evans, M.S., Kidd, K.A., Whittle, D.M., Drouillard, K., Wang, X., Anderson, M.R., Bronte, C.R., DeVault, D.S., Haffner, D., Payne, J., Kling, H.J. 2008. PCB concentrations in lake trout (Salvelinus namaycush) are correlated to habitat use and lake characteristics. Environ. Sci. Technol. 42: 8239-8244.

Higgins, S.N.*, Hecky, R.E., Guildford, S.J. 2008. The collapse of benthic macroalagal blooms in response to self-shading. Freshwater Biol. 53: 2557-2572.

Hiriart-Baer, V.P.*, Arciszewski, T.J., Malkin, S.*, Guildford, S.J., Hecky, R.E. 2008. Use of pulse amplitude modulated fluorescence to assess the physiological status of Cladophora sp. along a water quality gradient. J. Phycol. 44: 1604-1613.

Higgins, S.N.*, Malkin, S. Y.*, Howell, E. T., Guildford, S.J., Campbell, L.*, Hiriart-Baer, V.*, Hecky, R.E., 2008. An ecological review of Cladophora glomerata (Chlorophyta) in the Laurentian Great Lakes. J. Phycol. 44: 839-854.

Houde, M., Muir, D.C.G., Kidd, K.A., Guildford, S.J., Drouillard, K., Evans, M.S., Wang, X.,Whittle, D.M., Haffner, D., Kling, H.J. 2008. Influence of lake characteristics on the biomagnifications of persistent organic pollutants in lake trout food webs. Environ. Toxicol. Chem. 27: 2169-2178.

Wilson, A.E., Gossiauz, D.C., Höök, T.O., Berry, J.P., Landrum, P.F., Dyble, J., Guildford, S.J. 2008. Evaluation of the human health threat associated with the hepatotoxin, microcystin, in the muscle and liver tissues of yellow perch (Perca flavescens). Can.J.Fish.Aquat.Sci. 65: 1487-1497.

Gondwe, M.J.*, Guildford, S.J., Hecky. 2008. Planktonic nitrogen fixation in Lake Malawi/Nyasa. Hydrobiologia 596: 251-267.

North, R.L.*, Guildford, S.J., Smith, R.E.H., Twiss, M.R., Kling, H.J. 2008. Nitrogen, phosphorus, and iron colimitation of phytoplankton communities in the nearshore and offshore regions of the African Great Lakes. Verh. Internat. Verein. Limnol. 30: Part 2 259-264.

Malkin, S.Y.*, Guildford, S.J., Hecky, R.E. 2008. Modeling the growth response of Cladophora in a Laurentian Great Lake to the exotic invader Dreissena and to lake warming. Limnol. Oceanog. 53:1111-1124.

Guildford, S.J., Bootsma, H.A., Taylor, W.D., Hecky, R.E. 2007. High variability of phytoplankton photosynthesis in response to environmental forcing in oligotrophic Lake Malawi/Nyasa. J. Great Lakes Res. 33:170-185.

North, R.L.*, Guildford, S.J., Smith, R.E.H., Havens, S.M., Twiss, M.R. 2007. Evidence for phosphorus, nitrogen, and iron colimitation of phytoplankton communities in Lake Erie. Limnol. Oceanogr. 52: 315-328.

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