Dr. JoAnn Burkholder

Professor and Director of CAAE
William Neal Reynolds Distinguished Professor

Aquatic ecology and toxic dinoflagellates

Research Interests:

Over the past ten years, my research has been focused primarily in three areas in aquatic ecosystems:

  • Chronic effects of nutrient over-enrichment (eutrophication) and other chemical environmental contaminants (CECs) on aquatic plants (algae, angiosperms);
  • The ecology and impacts of harmful algae (cyanobacteria, dinoflagellates, haptophytes, raphidophytes; and
  • Influences of long-term (decadal+) changes in watershed land use and pollution sources on surface water quality.

I am the Director of the Center for Applied Aquatic Ecology (CAAE: http://www.ncsu.edu/wq/) located in the Department of Plant Biology at NCSU.  Our research team has designed and maintained a 14-year ongoing research and monitoring program on the Neuse Estuary.  We developed and patented an instrument that allows automated depth profiles of water quality on an hourly basis, 24/7, to track environmental changes, examine the ecology of harmful algae, and improve assessment of fish kill causality.  We also have designed and maintained a 6-year ongoing research and monitoring program in three major potable water supply reservoirs in North Carolina. We are working to combine our real-time, automated sampling capability with microarrays to detect toxic cyanobacteria (blue-green algae), pesticides and other CECs, and microbial pathogens to improve early warning systems to safeguard public water supplies.  We recently completed a decadal study on land use changes in the Neuse watershed, emphasizing the importance of both urban and agricultural pollutant sources. We documented a striking increase in ammonium concentrations, by more than 500%, in surface waters affected by numerous confined swine feed operations. The increased ammonium supply is significantly related to an increase in algal species such as the raphidophyte,Heterosigma akashiwo, that is potentially toxic to humans.  In earlier work, we co-discovered potentially toxic estuarine dinoflagellates (Pfiesteria piscicida, P. shumwayae), stimulated by nutrient over-enrichment, than can cause major fish kills. The findings provided the foundation for recent research by toxin chemists at NOAA (Charleston, SC), who described a group of potent Pfiesteria toxins, new to science, with potential application in treating memory disorders.

Selected Publications: (25 from 142)

Burkholder JM (2008, accepted) Harmful algal blooms. In: Encyclopedia of Inland Waters, by GE Likens (ed.) Elsevier, New York.

Burkholder JM, Frazier W, Rothenberger MB (2008, accepted) Source water assessment and treatment strategies for harmful and noxious algae.  In: Algae Manual, by the American Water Works Association (AWWA). AWWA, Denver.

Heisler J, Glibert P, Burkholder J, Anderson D, Cochlan W, Dennison W, Gobler C, Dortch Q, Heil C, Humphries E, Lewitus A, Magnien R, Marshall H, Stockwell D, Suddleson M. (2008, accepted) Eutrophication and harmful algal blooms: A scientific consensus. Harmful Algae.

Skelton HM, Burkholder JM, Parrow MW (2008, accepted) Axenic cultivation of the heterotrophic dinoflagellate Pfiesteria shumwayae and observations of feeding behavior. Journal of Phycology.

Touchette BW, Burkholder JM, Allen EH, Alexander JL, Kinder CA, James J, Britton CH (2007) Eutrophication and cyanobacteria blooms in run-of-river impoundments in North Carolina, U.S.A.  Lake and Reservoir Management 23:179-192.

Burkholder JM, Hallegraeff GM, Melia G, Cohen A, Bowers HA, Oldach DW, Parrow MW, Sullivan  MJ, Zimba PV, Allen EH, Mallin MA (2007) Phytoplankton and bacterial assemblages in ballast  water of U.S. military ships as a function of port of origin, voyage time and ocean exchange practices. Harmful Algae6:486-518.

Burkholder JM, Libra B, Weyer P, Heathcote S, Kolpin D, Thorne PS, Wichman M (2007) Impacts of waste from concentrated animal feeding operations on water quality. Environmental Health Perspectives 115:308-312.

Burkholder JM, Tomasko D, Touchette BW (2007) Seagrasses and eutrophication. Journal of Experimental Marine Biology and Ecology 350:46-72.

Burkholder JM, Dickey DA, Kinder C, Reed RE, Mallin MA, Melia G, McIver MR, Cahoon LB, Brownie C, Deamer N, Springer J, Glasgow H, Toms D, Smith J (2006) Comprehensive trend analysis of nutrients and related variables in a large eutrophic estuary: A decadal study of anthropogenic and climatic influences. Limnology and Oceanography 51:463-487.

Glibert PM, Burkholder JM, Parrow MW, Lewitus AJ, Gustafson DE (2006) Direct uptake of nitrogen byPfiesteria piscicida and Pfiesteria shumwayae, and nitrogen nutritional preferences. Harmful Algae 5:380-394.

Marshall HG, Hargraves PE, Burkholder JM, Parrow MW, Elbrächter M, Allen EH, Knowlton VM, Rublee PA, Hynes WL, Egerton TA, Remington DL, Wyatt KB, Lewitus AJ, Henrich VC (2006) Taxonomy of Pfiesteria(Dinophyceae). Harmful Algae 5:481-496.

Burkholder JM, Gordon AS, Moeller PD, Law JM, Coyne KJ, Lewitus AJ, Ramsdell JS, Marshall HG,  Deamer NJ, Cary SC, Kempton JW, Morton SL, Rublee PA (2005) Demonstration of toxicity to fish and to mammalian cells by Pfiesteria species: Comparison of assay methods and multiple strains. Proceedings of the National Academy of Sciences (U.S.A) 102:3471-3476.

Glibert PM, Seitzinger S, Heil CA, Burkholder JM, Parrow MW, Codispoti LA, Kelly V (2005) Eutrophication – new perspectives on its role in the global proliferation of harmful algal blooms. Oceanography 18:198-209.

Parrow MW, Burkholder JM, Deamer NJ, Ramsdell JS (2005) Contaminant-free cultivation of Pfiesteria shumwayae (Dinophyceae) on a fish cell line. Aquatic Microbial Ecology 39:97-105.

Springer JJ, Burkholder JM, Glibert PM, Reed RE (2005) Use of a real-time remote monitoring network and shipborne sampling to characterize a dinoflagellate bloom in the Neuse Estuary, North Carolina, U.S.A.Harmful Algae 4:533-551.

Burkholder J, Eggleston D, Glasgow H, Brownie C, Reed R, Melia G, Kinder C, Janowitz G, Corbett R, Posey M, Alphin T, Toms D, Deamer N, Springer J (2004) Comparative impacts of two major hurricane seasons on the Neuse River and western Pamlico Sound. Proceedings of the National Academy of Sciences (USA) 101:9291-9296.

Touchette BW, Burkholder JM, Glasgow HB (2003) Growth and developmental responses of eelgrass (Zostera marina L.) under increased temperature and water-column nitrate. Estuaries 26:142-155.

Burkholder JM (2001) Eutrophication and oligotrophication, pp. 649-670. In: Encyclopedia of Biodiversity, Vol. 2, by Levin S (ed.). Academic Press, New York.

Harvell CD, Kim K, Burkholder JM, Colwell RR, Epstein PR, Grimes J, Hofmann EE, Lipp E, Osterhaus ADME, Overstreet R., Porter JW, Smith GW, Vasta G (1999) Emerging marine diseases: Climate links and anthropogenic factors. Science 285:1505-1510.

Burkholder JM (1998) Implications of harmful marine microalgae and heterotrophic dinoflagellates in management of sustainable marine fisheries. Ecological Applications 8:S37-S62

Burkholder JM (1996) Interactions of benthic algae with their substrata, pp. 253-297. In: Benthic Algae in Freshwater Ecosystems, by RJ Stevenson, M Bothwell, and RL Lowe (eds.). Academic Press, New York.

Burkholder JM (1992) Phytoplankton and episodic suspended sediment loading: Phosphate partitioning and mechanisms for survival. Limnology and Oceanography 37:974-988.

Burkholder JM, Mason KM, Glasgow HB (1992) Water-column nitrate enrichment promotes decline of eelgrass (Zostera marina L.): Evidence from seasonal mesocosm experiments. Marine Ecology Progress Series 81:163-178.

Burkholder JM, Noga EJ, Hobbs CW, Glasgow HB, Smith SA (1992) New “phantom” dinoflagellate is the causative agent of major estuarine fish kills. Nature358:407-410, Nature 360:768.

Burkholder JM, Wetzel RG, Klomparens KL (1990) Direct comparison of phosphate uptake by adnate and loosely attached microalgae within an intact biofilm matrix. Applied and Environmental Microbiology56:2882-2890.