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Chesapeake Bay Program

Staff: Phytoplankton PI

Dr. Todd A. Egerton
ODU Adjunct Assistant Professor
VDH Marine Science Supervisor

Dr. Egerton is a phytoplankton taxonomist and marine ecologist. His research involves ongoing monitoring of phytoplankton communities in Chesapeake Bay and other freshwater and coastal habitats. A long-standing collaboration with state and federal partners involves analyses of water samples for the presence of harmful algal bloom species. This lab maintains one of the longest running phytoplankton monitoring programs of its kind, carrying on the work of Professor Emeritus Dr. Harold G. Marshall. Current projects include developing an understanding of algal bloom dynamics in Hampton Roads, focusing on identifying bloom initiation triggers. His work with VDH includes surveillance of biotoxin producing algae and guidance for shellfish management in the state. He is particularly interested in the causes and effects of phytoplankton biodiversity, studying algal diversity in habitats from tropical lakes to coastal marine waters. Much of his research has focused on dinoflagellates include the use of molecular data and morphological characteristics in taxonomy and phylogeny, and examining the roles of competition and predation in their life history. Previous projects have also included the use of algal biomass as a fuel source, with experience in large scale culturing and harvesting of freshwater phytoplankton.


Filippino, K.C., Egerton, T.A., Hunley, W.S. and Mulholland, M.R., 2017. The Influence of Storms on Water Quality and Phytoplankton Dynamics in the Tidal James River. Estuaries and Coasts, 40(1), pp.80-94.

Semcheski, M.R., Egerton, T.A. and Marshall, H.G., 2016. Composition and Diversity of Intertidal Microphytobenthos and Phytoplankton in Chesapeake Bay. Wetlands, 36(3), pp.483-496.

Egerton, T.A., Morse, R.E., Marshall, H.G. and Mulholland, M.R., 2014. Emergence of algal blooms: the effects of short-term variability in water quality on phytoplankton abundance, diversity, and community composition in a tidal estuary. Microorganisms, 2(1), pp.33-57.

Morse, R.E.; Mulholland, M.R.; Egerton, T.A.; Marshall. H.G. 2014. Daily variability in phytoplankton abundance and nutrient concentrations in a tidally dominated eutrophic estuary. Marine Ecology Progress Series. 503: 59-74.

Egerton, T. A., H. G. Marshall, and W. S. Hunley. 2012. Integration of microscopy and underway chlorophyll mapping for monitoring algal bloom development. in Oceans, 2012, IEEE.

Filippino, K.C., R. Morse, T. A. Egerton, W. Hunley, M. Mulholland. 2012. Storm chasing: nutrient dynamics in the tidal James River before, during, and after Hurricane Irene and Tropical Storm Lee. in Oceans, 2012, IEEE.

Marshall, H.G., and T.A. Egerton. 2012. Bloom and toxin producing algae in Virginia tidal rivers. in Oceans, 2012, IEEE.

Marshall, H. G., and T. A. Egerton. 2010. Increasing occurrence and development of potentially harmful algal blooms in Virginia tidal rivers. Pages 89-98 in P. Fay editor. Water Resources in Changing Climates. Virginia Water Resources Research Center, Richmond, Virginia, USA.

Mulholland, M.R., R. Morse, G. Boncillo, P. Bernhardt, K. Filippino, L. Procise,J. Blanc-Garcia, H.G. Marshall, T.A. Egerton, W. Hunley, K. Moore, D. Berry, and C. Gobler. 2009. Understanding causes and Impacts of the dinoflagellate, Cochlodinium polykrikoides, blooms in the Chesapeake Bay. Estuaries and Coasts, 32:734-747.

Marshall, H. G., and T. A. Egerton. 2009. Phytoplankton blooms: Their occurrence and composition within Virginia’s tidal tributaries. Virginia Journal of Science 60:149-164.

Marshall, H.G., L. Burchardt, T. A. Egerton, and M. Lane. 2008. Status of potentially harmful algae in the Chesapeake Bay estuarine system. In: Moestrup, O. et al. Proceedings of the 12th International Conference on Harmful Algae. International Society for the study of Harmful algae and Intergovernmental Oceanographic Commission of UNESCO. Copenhagen, pp. 203-205.

Marshall, H.G., L. Burchardt, T.A. Egerton, K. Stefankiak, and M. Lane. 2008. Potentially toxic cyanobacteria in Chesapeake Bay estuaries and a Virginia lake. In: H.K. Hudnell (ed.) Cyanobacterial Harmful Algal Blooms, State of the Science and Research Needs. Springer Sci. Publ., N.Y. pp. 172-17

Tang, Y.Z., T. A. Egerton, L. Kong and H. G. Marshall. 2008. Morphological variation and phylogenetic analysis of the dinoflagellate Gymnodinium aureolum from a tributary of Chesapeake Bay. Journal of Eukaryotic Microbiology. 55: 91-99.

Nesius, K., H. G. Marshall, and T. A. Egerton. 2007. Phytoplankton productivity in the tidal regions of four Chesapeake Bay tidal tributaries. Virginia Journal of Science 58: 191-204.

Egerton, T. A., and H. G. Marshall. 2006. Feeding preferences and grazing rates of Pfiesteria piscicida and a cryptoperidiniopsoid preying on fish blood cells and algal prey. Harmful Algae 5: 419-426.

Marshall, H. G., P. Hargraves, J. A. Burkholder, M. Parrow, M. Elbrachter, E. Allen, V. Knowlton, P. Rublee, W. Hynes, T. A. Egerton, D. Remington, K. Wyatt, K. Coyne, A. Lewitus, and V. Henrich. 2006a. Taxonomy of Pfiesteria (Dinophyceae). Harmful Algae 5:481-496.

Marshall, H.G., T.A. Egerton, L. Burchardt, S. Cerbin, M. Kokocinski. 2005. Long term monitoring results of harmful algal populations in Chesapeake Bay and its major tributaries in Virginia, USA. Oceanological and Hydrobiological Studies 34: 35-41.