@article{burkholder_dickey_kinder_reed_mallin_mciver_cahoon_melia_brownie_smith_et al._2006, title={Comprehensive trend analysis of nutrients and related variables in a large eutrophic estuary: A decadal study of anthropogenic and climatic influences}, volume={51}, DOI={10.4319/lo.2006.51.1_part_2.0463}, abstractNote={We used a decadal data set, with weekly to biweekly sampling in April—October and monthly sampling in November—March, to characterize climatic (hurricane‐level storms, a sustained 3‐yr drought) and anthropogenic influences on N and P concentrations and loadings to a large eutrophic, poorly flushed estuary, the Neuse Estuary of the Albemarle—Pamlico Estuarine System. Mass volume transport data were obtained with cross‐estuary transect flow measurements taken near the entrance to the estuary. Although trends were minimally influenced by hurricanes, analyses were significantly affected by the sustained drought near the end of the study. As examples, decreasing trends in total N (TN), total P (TP), and bottom‐water dissolved oxygen concentrations, and in TN loadings were significant considering all data, but these trends were not significant when the sustained drought was excluded from analysis. In addition, the trend in TN loading was especially sensitive to the initial sampling period. NH 4 + concentrations dramatically increased (overall by ~500%) as a persistent trend regardless of attempts to control for climatic events. An increasing trend in NH 4 + also was documented in an adjacent, rapidly flushed Coastal Plain estuary, the Cape Fear. The NH 4 + data suggest a regional‐scale effect of high inputs from inadequately controlled, increasing nonpoint sources. The fragility of TN loading trends, the striking increase in NH 4 + concentrations, and the lack of management emphasis on controlling nonpoint sources such as “new” industrialized swine production collectively do not support recent reports of achievement of a 30% reduction in TN loading to the Neuse. Nonpoint sources remain a critical target for reduction to alleviate the negative effects of cultural eutrophication in this system, as in many estuaries throughout the world.}, number={1}, journal={Limnology and Oceanography}, author={Burkholder, JoAnn M. and Dickey, David A. and Kinder, Carol A. and Reed, Robert E. and Mallin, Michael A. and McIver, Matthew R. and Cahoon, Lawrence B. and Melia, Greg and Brownie, Cavell and Smith, Joy and et al.}, year={2006}, month={Jan}, pages={463–487} }
 @article{lewitus_wetz_willis_burkholder_parrow_glasgow_2006, title={Grazing activity of Pfiesteria piscicida (Dinophyceae) and susceptibility to ciliate predation vary with toxicity status}, DOI={10.1016/j.hal.2006.04.012}, abstractNote={Variability has been reported in the toxicity potential of Pfiesteria piscicida that is partly a function of the history of exposure to live fish. Grazing properties of P. piscicida and its susceptibility to ciliate predation were compared in three functional types or toxicity states of this species: actively toxic cultures, cultures with temporary loss of demonstrable toxicity, and cultures with no demonstrable toxicity. Pronounced differences in predator–prey interactions were found between actively toxic cultures and cultures with reduced toxicity. When grown with Rhodomonas sp. (Cryptophyceae) prey, specific growth rates were relatively low in actively toxic cultures under both relatively high and low irradiances. In the cultures with reduced toxicity, prey chloroplast material was apparent in nearly 100% of dinoflagellate cells 3 h after feeding, while chloroplast inclusions were found in <40% of actively toxic cells for ≤16 h (high light) and ≤23 h (low light). These results suggest a relatively high reliance on phagotrophic carbon assimilation and more rapid response to algal prey availability in Pfiesteria cells with lower toxicity. Grazing by two euplotid benthic ciliates (Euplotes vannus and E. woodruffi) on P. piscicida also varied among functional types. Grazing on actively toxic P. piscicida cells did not occur, whereas net positive ingestion rates were calculated for the other prey cultures. These results support concurrent experimental findings that a natural assemblage of microzooplankton displayed lower grazing potential on actively toxic P. piscicida than on cultures with reduced toxicity. In summary, pronounced differences in trophic interactions were found between actively toxic cultures and those with reduced or undetectable toxicity, providing additional evidence of the importance of cellular toxicity in the trophic ecology of Pfiesteria.}, number={4}, journal={Harmful Algae}, author={Lewitus, Alan J. and Wetz, Michael S. and Willis, Bonnie M. and Burkholder, JoAnn M. and Parrow, Matthew W. and Glasgow, Howard B.}, year={2006}, month={May} }
 @misc{glasgow_reed_toms_burkholder_2006, title={Variable depth automated dynamic water profiler}, volume={7,040,157}, publisher={Washington, DC: U.S. Patent and Trademark Office}, author={Glasgow, H., Jr. and Reed, R. E. and Toms, D. C. and Burkholder, J.}, year={2006} }
 @article{burkholder_eggleston_glasgow_brownie_reed_janowitz_posey_melia_kinder_corbett_et al._2004, title={Comparative impacts of two major hurricane seasons on the Neuse River and western Pamlico Sound ecosystems}, volume={101}, DOI={10.1073/pnas.0306842101}, abstractNote={Ecosystem-level impacts of two hurricane seasons were compared several years after the storms in the largest lagoonal estuary in the U.S., the Albemarle–Pamlico Estuarine System. A segmented linear regression flow model was developed to compare mass-water transport and nutrient loadings to a major artery, the Neuse River Estuary (NRE), and to estimate mean annual versus storm-related volume delivery to the NRE and Pamlico Sound. Significantly less water volume was delivered by Hurricane Fran (1996), but massive fish kills occurred in association with severe dissolved oxygen deficits and high contaminant loadings (total nitrogen, total phosphorus, suspended solids, and fecal bacteria). The high water volume of the second hurricane season (Hurricanes Dennis, Floyd, and Irene in 1999) delivered generally comparable but more dilute contaminant loads, and no major fish kills were reported. There were no discernable long-term adverse impacts on water quality. Populations of undesirable organisms, such as toxic dinoflagellates, were displaced down-estuary to habitats less conducive for growth. The response of fisheries was species-dependent: there was no apparent impact of the hurricanes on commercial landings of bivalve molluscs or shrimp. In contrast, interacting effects of hurricane floodwaters in 1999 and intensive fishing pressure led to striking reductions in blue crabs. Overall, the data support the premise that, in shallow estuaries frequently disturbed by hurricanes, there can be relatively rapid recovery in water quality and biota, and benefit from the scouring activity of these storms.}, number={25}, journal={Proceedings of the National Academy of Sciences}, author={Burkholder, JoAnn and Eggleston, David and Glasgow, Howard and Brownie, Cavell and Reed, Robert and Janowitz, Gerald and Posey, Martin and Melia, Greg and Kinder, Carol and Corbett, Reide and et al.}, year={2004}, month={Jun}, pages={9291–9296} }
 @article{glasgow_burkholder_reed_lewitus_kleinman_2004, title={Real-time remote monitoring of water quality: a review of current applications, and advancements in sensor, telemetry, and computing technologies}, volume={300}, DOI={10.1016/j.jembe.2004.02.022}, abstractNote={Recent advances in communication and sensor technology have catalyzed progress in remote monitoring capabilities for water quality. As a result, the ability to characterize dynamic hydrologic properties at adequate temporal and spatial scales has greatly improved. These advances have led to improved statistical and mechanistic modeling in monitoring of water quality trends at local, watershed and regional scales for freshwater, estuarine and marine ecosystems. In addition, they have greatly enhanced rapid (e.g., real-time) detection of hydrologic variability, recognized as a critical need for early warning systems and rapid response to harmful algal bloom events. Here, we present some of the landmark developments and technological achievements that led to the advent of real-time remote monitors for hydrologic properties. We conclude that increased use and continuing advancements of real-time remote monitoring (RTRM) and sensing technologies will become a progressively more important tool for evaluating water quality. Recent engineering and deployment of RTRM technologies by federal and state regulatory agencies, industries, and academic laboratories is now permitting rapid detection of, and responses to, environmental threats imposed by increased nutrient loadings, development of hypoxic and anoxic areas, toxicants, and harmful algal bloom outbreaks leading to fish kill events and potential human health impacts.}, number={02-Jan}, journal={Journal of Experimental Marine Biology and Ecology}, author={Glasgow, Howard B and Burkholder, JoAnn M and Reed, Robert E and Lewitus, Alan J and Kleinman, Joseph E}, year={2004}, month={Mar}, pages={409–448} }
 @article{reed_glasgow_burkholder_brownie_2004, title={Seasonal physical–chemical structure and acoustic Doppler current profiler flow patterns over multiple years in a shallow, stratified estuary, with implications for lateral variability}, volume={60}, ISSN={0272-7714}, url={http://dx.doi.org/10.1016/j.ecss.2004.02.010}, DOI={10.1016/j.ecss.2004.02.010}, abstractNote={The overall goal of this study was to strengthen understanding of the hydrographic structure in shallow estuaries as influenced by seasonal and depth-dependent variability, and by variability from extreme meteorological events. The mesohaline Neuse Estuary, North Carolina, U.S.A., which was the focus, receives surface inputs from upriver and tributary freshwater sources and bottom inputs from downriver high-salinity sound water sources, resulting in varying degrees of stratification. To assess depth-dependent, estuary-wide changes in salinity, a multiple time series was created using data from four discrete depths (surface and 1, 2, and 3m±0.25m). The database was developed from weekly to biweekly sampling of the entire water column, and included side-channel as well as mid-channel data. We characterized seasonal differences in halocline depth affecting the hydrographic structure of the mesohaline estuary and site-specific variation in nutrient concentrations, based on a comprehensive eight-year physical/chemical database. The first two years of the record showed an expected seasonal signal and included events that impacted the surface layer from freshwater inputs. Remaining years had greater variability over seasons and depths, with freshening events that affected all depths. Halocline depth was compared at specific locations, and a “snapshot” view was provided of the relative depth of these water masses within the estuary by season. We also examined flow patterns at the same cross-estuary sites over a three-year period, using a boat-mounted acoustic Doppler current profiler (ADCP) with bottom-tracking capability. Composite visualizations constructed with single-transect ADCP data revealed a classical estuarine circulation pattern of outflow at the surface/southern shore and inflow at the bottom/northern shore. Although this pattern deviated under extreme climatological events and was sometimes variable, the estuary generally exhibited a high probability of direction of flow. Wind fields, hurricanes, and small-scale, high-precipitation events represented significant forcing variables.}, number={4}, journal={Estuarine, Coastal and Shelf Science}, publisher={Elsevier BV}, author={Reed, Robert E. and Glasgow, Howard B. and Burkholder, JoAnn M. and Brownie, Cavell}, year={2004}, month={Aug}, pages={549–566} }
 @article{tengs_bowers_glasgow_burkholder_oldach_2003, title={Identical ribosomal DNA sequence data from Pfiesteria piscicida (Dinophyceae) isolates with different toxicity phenotypes}, DOI={10.1016/s0013-9351(02)00087-7}, abstractNote={Complete small subunit ribosomal RNA, internal transcribed spacer 1 and 2, 5.8S, and partial large subunit ribosomal RNA gene sequences were generated from multiple isolates of Pfiesteria piscicida. Sequences were derived from isolates that have been shown to be ichthyotoxic as well as isolates that have no history of toxic behavior. All of the sequences generated were identical for the different cultures, and we therefore conclude that differences in toxicity seen between isolates of P. piscicida are linked to factors other than genetic strain variation detectable by ribosomal gene sequence analyses.}, number={1}, journal={Environmental Research}, author={Tengs, Torstein and Bowers, Holly A. and Glasgow, Howard B. and Burkholder, JoAnn M. and Oldach, David W.}, year={2003}, month={Apr} }
 @article{levin_blackwelder_glasgow_burkholder_moeller_ramsdell_2003, title={Learning impairment caused by a toxin produced by Pfiesteria piscicida infused into the hippocampus of rats}, DOI={10.1016/S0892-0362(03)00011-4}, abstractNote={Pfiesteria piscicida, an estuarine dinoflagellate, which has been shown to kill fish, has also been associated with neurocognitive deficits in humans. With a rat model, we have demonstrated the cause-and-effect relationship between Pfiesteria exposure and learning impairment. In several studies, we have replicated the finding in Sprague–Dawley rats that exposure to fixed acute doses of Pfiesteria cells or filtrates caused radial-arm maze learning impairment. Recently, this finding of Pfiesteria-induced learning impairment in rats has been independently replicated in another laboratory as well. We have demonstrated significant Pfiesteria-induced learning impairment in both the win-shift and repeated-acquisition tasks in the radial-arm maze and in reversal learning in a visual operant signal detection task. These learning impairments have been seen as long as 10 weeks after a single acute exposure to Pfiesteria. In the current study, we used a hydrophilic toxin isolated from clonal P. piscicida cultures (PfTx) and tested its effect when applied locally to the ventral hippocampus on repeated acquisition of rats in the radial-arm maze. Toxin exposure impaired choice accuracy in the radial-arm maze repeated acquisition procedure. The PfTx-induced impairment was seen at the beginning of the session and the early learning deficit was persistent across 6 weeks of testing after a single administration of the toxin. Eventually, with enough practice, in each session, the PfTx-exposed rats did learn that session's problem as did control rats. This model has demonstrated the cause-and-effect relationship between exposure to a hydrophilic toxin produced by P. piscicida and learning impairment, and specifically that the ventral hippocampus was critically involved.}, number={4}, journal={Neurotoxicology and Teratology}, author={Levin, Edward D. and Blackwelder, W.Paul and Glasgow, Howard B. and Burkholder, JoAnn M. and Moeller, Peter D.R. and Ramsdell, John S.}, year={2003}, month={Mar} }
 @article{brownie_glasgow_burkholder_reed_tang_2003, title={Re-evaluation of the Relationship between Pfiesteria and Estuarine Fish Kills}, volume={6}, DOI={10.1007/s10021-002-0194-5}, number={1}, journal={Ecosystems}, author={Brownie, Cavell and Glasgow, Howard B. and Burkholder, JoAnn M. and Reed, Robert and Tang, Yongqiang}, year={2003}, month={Jan}, pages={1–10} }
 @article{touchette_burkholder_glasgow_2003, title={Variations in eelgrass (Zostera marina L.) morphology and internal nutrient composition as influenced by increased temperature and water column nitrate}, DOI={10.1007/BF02691701}, number={1}, journal={Estuaries}, author={Touchette, Brant W. and Burkholder, JoAnn M. and Glasgow, Howard B.}, year={2003}, month={Feb} }
 @article{rhodes_burkholder_glasgow_rublee_allen_adamson_2002, title={<i>Pfiesteria shumwayae</i> (Pfiesteriaceae) in New Zealand}, DOI={10.1080/00288330.2002.9517117}, abstractNote={Abstract Pfiesteria shumwayae Steidinger et Burkholder is now known to be present in New Zealand and occurs in estuaries around the country. The presence of Pfiesteria was initially determined by a polymerase chain reaction (PCR)‐based detection assay, using oligonucleotide primers targeted at ribosomal DNA extracted from estuarine water and sediments. Presence was confirmed by isolation from fresh sediments in the presence offish (Oreochromis mossambicus) , followed by identification by scanning electron microscopy. The New Zealand isolates of P. shumwayae were ichthyotoxic in bioassays, but there is no historic evidence offish kills in New Zealand associated with the dinoflagellate.}, number={3}, journal={New Zealand Journal of Marine and Freshwater Research}, author={Rhodes, Lesley L. and Burkholder, Joann M. and Glasgow, Howard B. and Rublee, Parke A. and Allen, Coy and Adamson, Janet E.}, year={2002}, month={Sep} }
 @article{jakobsen_tengs_vatne_bowers_oldach_burkholder_glasgow_rublee_klaveness_2002, title={Discovery of the toxic dinoflagellate <i>Pfiesteria</i> in northern European waters}, DOI={10.1098/rspb.2001.1852}, abstractNote={Several dinoflagellate strains of the genus Pfiesteria were isolated by culturing techniques from sediment samples taken in the Oslofjord region of Norway. Pfiesteria piscicida, well known as a fish killer from the Atlantic coast of America, was identified by genetic methods and light microscopy. The related species Pfiesteria shumwayae was attracted from the sediment by the presence of fish, and has proved toxic. This present survey demonstrates the wide distribution of these potentially harmful species, but so far they have not been connected with fish kills in Europe.}, number={1487}, journal={Proceedings of the Royal Society B Biological Sciences}, author={Jakobsen, Kjetill S. and Tengs, Torstein and Vatne, Andreas and Bowers, Holly A. and Oldach, David W. and Burkholder, JoAnn M. and Glasgow, Howard B. and Rublee, Parke A. and Klaveness, Dag}, year={2002}, month={Jan} }
 @article{stoecker_parrow_burkholder_glasgow_2002, title={Grazing by microzooplankton on Pfiesteria piscicida cultures with different histories of toxicity}, DOI={10.3354/ame028079}, abstractNote={AME Aquatic Microbial Ecology Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsSpecials AME 28:79-85 (2002) - doi:10.3354/ame028079 Grazing by microzooplankton on Pfiesteria piscicida cultures with different histories of toxicity Diane K. Stoecker1,*, Matthew W. Parrow2, JoAnn M. Burkholder2, Howard B. Glasgow Jr.2 1University of Maryland Center for Environmental Science, Horn Point Laboratory, PO Box 775, Cambridge, Maryland 21613, USA 2Center for Applied Aquatic Ecology, North Carolina State University, Raleigh, North Carolina 27695, USA *E-mail: stoecker@hpl.umces.edu ABSTRACT: Susceptibility of actively toxic (TOX-A) zoospores, temporarily non-toxic (TOX-B) zoospores, and zoospores non-inducible to toxicity (NON-IND) of Pfiesteria piscicida to microzooplankton grazing was compared in a laboratory experiment. Zoospores from all cultures were ingested by microzooplankton, but community grazing coefficients for TOX-A were <20% of those for TOX-B or NON-IND zoospores in 6 h incubations. Tintinnids and strobilidiid ciliates that fed on P. piscicida declined in incubations containing TOX-A zoospores. There was no decline in a strombidiid ciliate or heterotrophic dinoflagellate populations that fed on TOX-A zoospores. These data suggest that, although microzooplankton grazing on non-toxic zoospores can be a significant source of mortality to planktonic populations of P. piscicida, grazing on toxic or very recently toxic zoospores is relatively low. KEY WORDS: Pfiesteria piscicida · Zoospores · Toxicity · Microzooplankton · Grazing Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in AME Vol. 28, No. 1. Online publication date: May 16, 2002 Print ISSN: 0948-3055; Online ISSN: 1616-1564 Copyright © 2002 Inter-Research.}, number={1}, journal={Aquatic Microbial Ecology}, author={Stoecker, DK and Parrow, MW and Burkholder, JM and Glasgow, HB}, year={2002}, month={Jan} }
 @article{springer_shumway_burkholder_glasgow_2002, title={Interactions between the toxic estuarine dinoflagellate Pfiesteria piscicida and two species of bivalve molluscs}, DOI={10.3354/meps245001}, abstractNote={MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 245:1-10 (2002) - doi:10.3354/meps245001 Interactions between the toxic estuarine dinoflagellate Pfiesteria piscicida and two species of bivalve molluscs Jeffrey J. Springer1,*, Sandra E. Shumway2, JoAnn M. Burkholder1, Howard B. Glasgow1 1Center for Applied Aquatic Ecology, North Carolina State University, 620 Hutton Street, Suite 104, Raleigh, North Carolina 27606, USA 2Department of Marine Sciences, University of Connecticut, 1080 Shennecossett Road, Groton, Connecticut 06340, USA *Email: jeff_springer@ncsu.edu ABSTRACT: Toxic strains of Pfiesteria spp. produce toxin(s) that can cause finfish death, but much less is known about impacts of Pfiesteria on shellfish. Here we conducted 4 experiments to examine interactions between shellfish and toxic (actively toxic or TOX-A from finfish-killing cultures and potentially toxic or TOX-B from cultures without finfish) and non-inducible (NON-IND, apparently incapable of killing fish via a toxic effect) strains of P. piscicida. First (Expt 1), we documented direct physical attack by P. piscicida TOX-A, TOX-B, and NON-IND zoospores on larvae of the bay scallop Argopecten irradians (Lamarck, 1819) and the eastern oyster Crassostrea virginica (Gmelin, 1791). Within 5 min zoospores swarmed around larvae that had discarded their vela, and attached with their peduncles. Within 15 min they had penetrated into the shellfish visceral cavity and had begun to feed aggressively; after 30 min all shellfish tissues except the adductor muscle had been consumed. Second, we tested the response of scallop larvae to P. piscicida (TOX-A or TOX-B) or cryptomonads (as controls) that were held in dialysis tubing (0.22 µm porosity) to prevent direct contact. After 60 min larval survival was 0% in the TOX-A treatment, 100% in the cryptomonad control, and intermediate in TOX-B and TOX-B + cryptomonad treatments. The data indicate a toxic effect of P. piscicida zoospores on the larvae, separate from the physical effect shown in Expt 1. Third, we compared grazing by juvenile and adult oysters on TOX-A, TOX-B, and NON-IND P. piscicida zoospores from the medium. After 60 min, grazing by juvenile oysters significantly differed as NON-IND >> TOX-B >> TOX-A. In contrast, adult oysters grazed significantly fewer TOX-A zoospores and maintained comparable grazing on TOX-B and NON-IND zoospores. Thus juvenile oysters, but not adults, were sensitive to residual toxicity of TOX-B zoospores, and both life-history stages were sensitive to TOX-A zoospores. The adverse effects of toxic strains on larval survival and juvenile grazing indicate that P. piscicida could potentially affect shellfish recruitment. Fourth, we assessed zoospore survival after passage through the digestive tract of adult oysters. The feces contained many temporary cysts from zoospores, and within 24 h >75% of the cysts produced motile cells. The data indicate that adult oysters would be poor biocontrol agents of P. piscicida, given the high survival of ingested zoospores following gut passage and fecal elimination; and that oysters could act as vectors of toxic P. piscicida strains if transported from affected estuaries to other waters. KEY WORDS: Argopecten irradians · Crassostrea virginica · Oyster · Pfiesteria · Scallop · Shellfish · Temporary cyst · Toxic dinoflagellate Full text in pdf format NextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 245. Online publication date: December 18, 2002 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2002 Inter-Research.}, number={2002}, journal={Marine Ecology Progress Series}, author={Springer, JJ and Shumway, SE and Burkholder, JAM and Glasgow, HB}, year={2002}, month={Jan} }
 @article{lewitus_hayes_willis_burkholder_glasgow_holland_maier_rublee_magnien_2002, title={Low abundance of the dinoflagellates,Pfiesteria piscicida, P. shumwayae, andCryptoperidiniopsis spp., in South Carolina tidal creeks and open estuaries}, DOI={10.1007/BF02804892}, number={4A}, journal={Estuaries}, author={Lewitus, Alan J. and Hayes, Kenneth C. and Willis, Bonnie M. and Burkholder, JoAnn M. and Glasgow, Howard B. and Holland, A. Fred and Maier, Philip P. and Rublee, Parke A. and Magnien, Robert}, year={2002}, month={Aug} }
 @article{burkholder_glasgow_2002, title={THE LIFE CYCLE AND TOXICITY OF <i>PFIESTERIA PISCICIDA</i> REVISITED<sup>1</sup>}, DOI={10.1046/j.1529-8817.2002.02096.x}, abstractNote={Despite use of excellent molecular techniques, Litaker et al. (2002) cannot provide insights about the life history of toxic Pfiesteria piscicida because they showed no data in support of having used toxic strains; rather they presented evidence that they used non‐inducible strains. Litaker et al. did not find amoeboid stages or a chrysophyte‐like cyst stage in several cultures and unequivocally concluded that the stages do not exist in all P. piscicida strains. Thus, they did not consider the tenet that absence of evidence does not constitute proof of absence. Apparent discrepancies between the research by Litaker et al. and previous research on Pfiesteria can be resolved as follows: First, Litaker et al. did not use toxic strains. We have reported findings (similar to Litaker et al.) showing few amoeboid transformations in non‐inducible strains, which manifest some but not all of the forms that have been documented in some toxic strains. We, and others, have documented active toxicity to fish, transformations to amoebae, and chrysophyte‐like cysts in some clonal toxic strains. Second, the data from several recent publications, which were available but not mentioned by Litaker et al. or by Coats (2002) in accompanying commentary, have verified P. piscicida amoebae, chrysophyte‐like cysts, and other stages in some toxic strains through a combination of approaches including PCR data from clonal cultures.}, number={6}, journal={Journal of Phycology}, author={Burkholder, JoAnn M. and Glasgow, Howard B.}, year={2002}, month={Dec} }
 @article{glasgow_burkholder_morton_springer_2001, title={A second species of ichthyotoxic Pfiesteria (Dinamoebales, Dinophyceae)}, DOI={10.2216/i0031-8884-40-3-234.1}, abstractNote={A second toxic species within the family Pfiesteriaceae, Pfiesteria shumwayae Glasgow & Burkholder sp. nov., is described from the New River Estuary and the Neuse Estuary of the Albemarle-Pamlico Estuarine Ecosystem, USA. The species is polymorphic and multiphasic, with flagellated, amoeboid and cyst stages. The flagellated zoospores (diameter 8–24 μm) have permanently condensed chromosomes (mesokaryotic nucleus); a chrysophyte-like cyst (diameter 6–25 μm)with organic scales and bracts; and thin thecal plates arranged in a Kofoidian series of Po, cp, X, 4′, la, 6″, 6c, 4s, 5″′, 2″″. The benthic filopodial (filose), lobopodia1 (lobose) and rhizopodial amoeboid stages (5–250 μm) have an outer covering that ranges from rough to smooth in texture, depending on the stage of origin and the prey source. Pfiesteria shumwayae amoebae have a normal eukaryote nucleus and cysts of multiple sizes (diameter 4–25 μm) with a reticulate outer covering. Toxic strains of the two Pfiesteria species have overlapping distributions in the mid-Atlantic and southeastern United States and Scandinavia, with toxic P. shumwayae also having been verified from New Zealand. Pfiesteria shumwayae is similar to P. piscicida in its complex life cycle, general nutrition, attraction to live fish prey, and ichthyotoxic activity that is stimulated by the presence of live fish or their fresh tissues and excreta. However, it can be distinguished from P. piscicida morphologically by having six precingular plates and a four-sided la plate, as well as genetically, on the basis of its ISS ribosomal DNA sequence.}, number={3}, journal={Phycologia}, author={Glasgow, H. B. and Burkholder, J. M. and Morton, S. L. and Springer, J.}, year={2001}, month={May} }
 @article{cancellieri_burkholder_deamer-melia_glasgow_2001, title={Chemosensory attraction of zoospores of the estuarine dinoflagellates, Pfiesteria piscicida and P. shumwayae, to finfish mucus and excreta}, DOI={10.1016/S0022-0981(01)00299-4}, abstractNote={Toxic strains of the estuarine dinoflagellates, Pfiesteria piscicida and P. shumwayae, can cause fish death and disease, whereas other estuarine ‘lookalike’ species such as cryptoperidiniopsoids have not been ichthyotoxic under ecologically relevant conditions. Chemosensory attraction of three functional types of these Pfiesteria spp. were separately evaluated for their attraction to fresh fish mucus and excreta. Clonal cultures of actively toxic (TOX-A, engaged in killing fish) and temporarily nontoxic (tested as toxic but without access to live fish for >1 week to 5 months (in most experiments, ≤3 months) as ‘short-duration’ TOX-B; and without access to live fish for ≥1.5 years as ‘long-duration’ TOX-B) functional types of P. piscicida and P. shumwayae were derived from the same clones whereas the non-inducible cultures (NON-IND, tested as incapable of toxic activity in the presence of fish), of necessity, were from different clonal isolates. NON-IND cultures previously had been grown on algal prey for 3–8 months, and had repeatedly been tested as incapable of causing fish distress, disease or death via toxic activity. Attraction to fish materials was based on the number of zoospores that entered microcapillary tubes containing sterile-filtered 15-ppt water (controls), vs. entry into tubes with sterile-filtered mucus and excreta (collected in 15-ppt water) that had been collected from live tilapia, bluegill, hybrid striped bass, and Atlantic menhaden (tested separately within 3 h of removal from live fish). TOX-A zoospores of both Pfiesteria species exhibited the strongest attraction to the fish mucus and excreta, with comparable response to the materials from all four test fish species. Short-duration TOX-B zoospores showed an intermediate response that apparently depended on the duration of mucus separation from the live fish: the shorter the separation period, the stronger the zoospore attraction to the fish materials. In contrast to TOX-A and short-duration TOX-B zoospores, NON-IND and long-duration TOX-B zoospores generally showed little or no response to the fish materials. Zoospores of the cryptoperidiniopsoid demonstrated a moderate attraction that did not appear to depend on the time of isolation from fish. TOX-A zoospores were also tested for attraction to sterile-filtered vs. non-filtered fish mucus (time separated from the live animal, 3–96 h). These zoospores, which initially had been actively attracted, were no longer attracted to the unfiltered fish materials after 48 h, whereas attraction to the sterile-filtered fish mucus and excreta persisted throughout the duration of the experiment. Thus, the attractant signal in the materials was degraded or effectively blocked by the bacterial community within hours of isolation from live fish. This study indicates the importance of functional type or toxicity status, and the importance of the history of exposure to live fish, in the behavioral ecology of Pfiesteria spp. Initial attraction to fish materials strongly depended on the functional type, and on the history of toxic activity. Non-inducible and long-duration TOX-B cultures of Pfiesteria spp., unlike actively toxic and short-duration TOX-B (potentially toxic) strains, initially were virtually unresponsive to fish mucus.}, number={1}, journal={Journal of Experimental Marine Biology and Ecology}, author={Cancellieri, Paul J. and Burkholder, JoAnn M. and Deamer-Melia, Nora J. and Glasgow, Howard B.}, year={2001}, month={Sep} }
 @article{moeller_morton_mitchell_sivertsen_fairey_mikulski_glasgow_deamer-melia_burkholder_ramsdell_2001, title={Current Progress in Isolation and Characterization of Toxins Isolated from Pfiesteria piscicida}, DOI={10.2307/3454921}, abstractNote={Peter D. R. Moeller, Steve L. Morton, Brad A. Mitchell, Scott K. Sivertsen, Elizabeth R. Fairey, Tina M. Mikulski, Howard Glasgow, Nora J. Deamer-Melia, JoAnn M. Burkholder, John S. Ramsdell, Current Progress in Isolation and Characterization of Toxins Isolated from Pfiesteria piscicida, Environmental Health Perspectives, Vol. 109, Supplement 5: Pfiesteria: From Biology to Public Health (Oct., 2001), pp. 739-743}, number={2001 Oct}, journal={Environmental Health Perspectives}, author={Moeller, Peter D. R. and Morton, Steve L. and Mitchell, Brad A. and Sivertsen, Scott K. and Fairey, Elizabeth R. and Mikulski, Tina M. and Glasgow, Howard and Deamer-Melia, Nora J. and Burkholder, JoAnn M. and Ramsdell, John S.}, year={2001}, month={Oct} }
 @article{glasgow_burkholder_mallin_deamer-melia_reed_2001, title={Field Ecology of Toxic Pfiesteria Complex Species and a Conservative Analysis of Their Role in Estuarine Fish Kills}, DOI={10.2307/3454919}, number={2001 Oct}, journal={Environmental Health Perspectives}, author={Glasgow, Howard B. and Burkholder, JoAnn M. and Mallin, Michael A. and Deamer-Melia, Nora J. and Reed, Robert E.}, year={2001}, month={Oct} }
 @article{burkholder_glasgow_2001, title={History of Toxic Pfiesteria in North Carolina Estuaries from 1991 to the Present}, DOI={10.1641/0006-3568(2001)051[0827:HOTPIN]2.0.CO;2}, abstractNote={ArticlesT he fish kills for which Pfiesteria became well known began in North Carolina, when very little research had been conducted on this unusual dinoflagellate.North Carolina's Albemarle-Pamlico Estuarine System, the epicenter of toxic Pfiesteria outbreaks, is the second largest estuary in area on the US mainland and the most important fish nursery ground on the US Atlantic Coast (Burkholder and Glasgow 1997, Mallin et al. 2000).As a conservative estimate, the state had sustained 48 toxic Pfiesteria outbreaks by 1997, involving more than a billion fish in an area more than 100 km 2 (Burkholder et al. 2001a).These events had occurred nearly every summer beginning in 1991, when the organism was first recognized as an estuarine, fish-killing agent (Burkholder et al. 1992, 2001a, Burkholder and Glasgow 1997).In 1997, 50,000 fish died in a small area of the Chesapeake Bay from toxic Pfiesteria , and press coverage of the event was like an explosion.In the same summer, 1.2 million fish died during toxic Pfiesteria outbreaks in Albemarle-Pamlico estuaries, a 4-hour drive south of Washington, DC; those deaths went virtually unmentioned.North Carolina was the first state to encounter toxic Pfiesteria, and the knowledge gained there, especially about toxic Pfiesteria outbreaks and health impacts on laboratory workers (Burkholder et al. 1992, 1995, Burkholder and Glasgow 1995, 1997, Glasgow et al. 1995), benefited Maryland officials, who were challenged to act quickly and decisively.They evaluated and rapidly verified the role of toxic Pfiesteria in the Chesapeake Bay outbreak (MDNR 1998).Maryland was the first state from which people who reported neurocognitive, respiratory, and other symptoms from environmental exposure were clinically evaluated within a short period (1-3 weeks) after being exposed (Grattan et al. 1998).Maryland was also the first state to address the Pfiesteria problem by making significant advances in legislation for protection of water quality (State of Maryland 1998).Congressional attention following the toxic Pfiesteria outbreaks in Maryland led to the appropriation of many millions of dollars to federal agencies to research and manage toxic Pfiesteria outbreaks, resulting in excellent progress in some areas and setbacks in others.Here we examine the history of toxic Pfiesteria outbreaks before the four in Chesapeake Bay and a few aspects of the aftermath, from the perspective and experience of our research in the Albemarle-Pamlico Estuarine System with high toxic Pfiesteria activity.An important part of the Pfiesteria story is how North Carolina-with 98% of the Pfiesteria problem-subsequently moved to strengthen water resource protection, environmental education, and support of Pfiesteria research, actions that would not have been possible without the events that unfolded in Chesapeake Bay.}, number={10}, journal={BioScience}, author={BURKHOLDER, JOANN M. and GLASGOW, HOWARD B.}, year={2001}, month={Jan} }
 @article{kimm-brinson_moeller_barbier_glasgow_burkholder_ramsdell_2001, title={Identification of a P2X7 Receptor in GH 4 C 1 Rat Pituitary Cells: A Potential Target for a Bioactive Substance Produced by Pfiesteria piscicida}, DOI={10.2307/3454703}, abstractNote={We examined the pharmacologic activity of a putative toxin (pPfTx) produced by Pfiesteria piscicida by characterizing the signaling pathways that induce the c-fos luciferase construct in GH(4)C(1) rat pituitary cells. Adenosine-5'-triphosphate (ATP) was determined to increase and, at higher concentrations, decrease luciferase activity in GH(4)C(1) rat pituitary cells that stably express c-fos luciferase. The inhibition of luciferase results from cytotoxicity, characteristic of the putative P. piscicida toxin (pPfTx). The actions of both pPfTx and ATP to induce c-fos luciferase were inhibited by the purinogenic receptor antagonist pyridoxalphosphate-6-azophenyl-2',4'-disulfonic acid (PPADS). Further characterization of a P2X receptor on the GH(4)C(1) cell was determined by the analog selectivity of P2X agonists. The P2X1/P2X3 agonist alpha,beta-methylene ATP (alpha,beta-MeATP) failed to increase or decrease c-fos luciferase. However, the P2X7 agonist 2',3'-(4-benzoyl)benzoyl ATP (BzATP), which had a predominant cytotoxic effect, was more potent than ATP. Immunoblot analysis of GH(4)C(1) cell membranes confirmed the presence of a 70-kDa protein that was immunoreactive to an antibody directed against the carboxy-terminal domain unique to the P2X7 receptor. The P2X7 irreversible antagonist oxidized-ATP (oxATP) inhibited the action of ATP, BzATP, and pPfTx. These findings indicate that GH(4)C(1) cells express purinogenic receptors with selectivity consistent with the P2X7 subtype and that this receptor pathway mediates the induction of the c-fos luciferase reporter gene by ATP and the putative Pfiesteria toxin}, number={5}, journal={Environmental Health Perspectives}, author={Kimm-Brinson, Karen L. and Moeller, Peter D. R. and Barbier, Michele and Glasgow, Howard and Burkholder, JoAnn M. and Ramsdell, John S.}, year={2001}, month={May} }
 @article{melo_moeller_glasgow_burkholder_ramsdell_2001, title={Microfluorimetric Analysis of a Purinergic Receptor (P2X 7 ) in GH 4 C 1 Rat Pituitary Cells: Effects of a Bioactive Substance Produced by Pfiesteria piscicida}, DOI={10.2307/3454920}, number={2001 Oct}, journal={Environmental Health Perspectives}, author={Melo, Ana Clara and Moeller, Peter D. R. and Glasgow, Howard and Burkholder, JoAnn M. and Ramsdell, John S.}, year={2001}, month={Oct} }
 @article{burkholder_glasgow_deamer-mella_2001, title={Overview and present status of the toxic Pfiesteria complex (Dinophyceae)}, DOI={10.2216/i0031-8884-40-3-186.1}, abstractNote={This paper reviews the Pfiesteria issue and Pfiesteria science and presents new information on variation in toxicity among Pfiesteria strains, culture effects on their toxicity, the trophic interactions of Pfiesteria spp ., and impacts on fish and mammals. We also assess Pfiesteria spp. impacts on fish in comparison to certain other estuarine dinoflagellates of similar appearance. Species of the toxic Pfiesteria complex (TPC) thus far include P. piscicida and P. shumwayae. These species share morphological and genetic similarities, and both have toxic strains that (1) show strong attraction to live fish;(2) exhibit toxicity that is triggered by live fish or their fresh tissues and excreta; and (3) produce toxin(s) that cause fish stress, disease and death under ecologically relevant conditions (the standardized fish bioassay process involves testing live Pfiesteria cells at similar densities to those encountered during Pfiesteria-related fish kill/disease events). Both Pfiesteria species also have a complex life cycle with multiple amoeboid, flagellated and cyst stages, several of which are ichthyotoxic. TPC species are eurythermal and euryhaline, with prey spanning the estuarine food web, from bacteria to mammalian tissues. They can be stimulated directly or indirectly by nitrogen and phosphorus enrichment. Toxic strains can be either actively or potentially toxic (the TOX-A and TOX-B functional types, respectively); in addition, c.40% of randomly isolated clones have been found to be benign [the noninducible or NON-IND functional type, which apparently lacks the ability to produce bioactive substances (toxins) that cause fish disease or death]. These functional types differ significantly in response to algal prey, predators, nutrients and fish. Moreover, as an apparent artifact of culture conditions, toxic strains generally lose their ability to cause fish death and disease and become NON-IND within weeks to months. At low cell densities, toxic strains can be causative agents of acute and/or chronic diffuse and focal lesions and of other fish diseases, as demonstrated in fish bioassays. A partially purified, water-soluble Pjiesteria toxin disrupts calcium metabolism in rat pituitary cells and mimics an adenosine triphosphate neurotransmitter that targets P2X7 purinoreceptors found predominantly on immune cells. Respiratory, visual, and neurological impacts have been sustained by people exposed to aerosols from fish-killing Pfiesteria cultures or to water and aerosols during estuarine fish kills associated with toxic Pfiesteria. Neurocognitive impacts from exposure to toxic Pfiesteria have been replicated experimentally in small mammals. Toxic strains of Pfiesteria species have been confirmed from mid-Atlantic and Gulf Coast estuaries in the United States and from northern Europe and New Zealand, indicating that these toxic dinoflagellates are cosmopolitan in distribution.}, number={3}, journal={Phycologia}, author={Burkholder, Joann M. and Glasgow, Howard B. and Deamer-Mella, Nora}, year={2001}, month={May} }
 @article{burkholder_glasgow_deamer-melia_springer_parrow_zhang_cancellieri_2001, title={Species of the Toxic Pfiesteria Complex, and the Importance of Functional Type in Data Interpretation}, DOI={10.2307/3454912}, number={2001 Oct}, journal={Environmental Health Perspectives}, author={Burkholder, JoAnn M. and Glasgow, Howard B. and Deamer-Melia, Nora J. and Springer, J. and Parrow, Matthew W. and Zhang, Cheng and Cancellieri, Paul J.}, year={2001}, month={Oct} }
 @article{rezvani_bushnell_burkholder_glasgow_levin_2001, title={Specificity of cognitive impairment from Pfiesteria piscicida exposure in rats}, DOI={10.1016/S0892-0362(01)00169-6}, abstractNote={Pfiesteria piscicida is a toxic dinoflagellate that has caused massive fish kills in estuaries along the East Coast of the United States, and exposure of humans to toxic Pfiesteria has been associated with cognitive impairment. A visual signal detection task was used to determine the possible importance of attentional and visual processes in Pfiesteria effects on cognitive function. Adult female rats were trained to perform the signal detection task. After training, the rats were injected subcutaneously with fish culture water containing toxic Pfiesteria (35,600 or 106,800 cells of Pfiesteria/kg of rat body weight) or with (control) fish culture water containing no Pfiesteria. Effects of toxic Pfiesteria on maintenance of signal detection behavior were assessed for 2 weeks after treatment. Then, the signal-response contingencies were reversed. After the discrimination was reestablished on the reversed levers, the rats received a second dose of toxic Pfiesteria. The rats were again tested for 2 weeks, after which a second reversal was imposed. Pfiesteria did not affect behavior in the signal detection task during 2 weeks of prereversal testing after either exposure. However, a significant Pfiesteria-induced deficit emerged when the signal-response contingencies were reversed. These findings suggest that Pfiesteria-induced deficits emerge during periods of behavioral transition and not during performance of previously learned tasks.}, number={6}, journal={Neurotoxicology and Teratology}, author={Rezvani, Amir H. and Bushnell, Philip J. and Burkholder, JoAnn M. and Glasgow, Howard B. and Levin, Edward D.}, year={2001}, month={Nov} }
 @article{burkholder_marshall_glasgow_seaborn_deamer-melia_2001, title={The Standardized Fish Bioassay Procedure for Detecting and Culturing Actively Toxic Pfiesteria, Used by Two Reference Laboratories for Atlantic and Gulf Coast States}, DOI={10.2307/3454922}, number={2001 Oct}, journal={Environmental Health Perspectives}, author={Burkholder, JoAnn M. and Marshall, Harold G. and Glasgow, Howard B. and Seaborn, David W. and Deamer-Melia, Nora J.}, year={2001}, month={Oct} }
 @article{rublee_kempton_schaefer_allen_harris_oldach_bowers_tengs_burkholder_glasgow_2001, title={Use of Molecular Probes to Assess Geographic Distribution of Pfiesteria Species}, DOI={10.2307/3454924}, abstractNote={We have developed multiple polymerase chain reaction (PCR)-based methods for the detection of Pfiesteria sp. in cultures and environmental samples. More than 2,100 water and sediment samples from estuarine sites of the U.S. Atlantic and gulf coasts were assayed for the presence of Pfiesteria piscicida Steidinger & Burkholder and Pfiesteria shumwayae Glasgow & Burkholder by PCR probing of extracted DNA. Positive results were found in about 3% of samples derived from routine monitoring of coastal waters and about 8% of sediments. The geographic range of both species was the same, ranging from New York to Texas. Pfiesteria spp. are likely common and generally benign inhabitants of coastal areas, but their presence maintains a potential for fish and human health problems. Key words: molecular probes, PCR, Pfiesteria, toxic dinoflagellates.}, number={2001 Oct}, journal={Environmental Health Perspectives}, author={Rublee, Parke A. and Kempton, Jason W. and Schaefer, Eric F. and Allen, Coy and Harris, Janera and Oldach, David W. and Bowers, Holly and Tengs, Torstein and Burkholder, JoAnn M. and Glasgow, H. B.}, year={2001}, month={Oct} }
 @article{bowers_tengs_glasgow_burkholder_rublee_oldach_2000, title={Development of Real-Time PCR Assays for Rapid Detection of <i>Pfiesteria piscicida</i> and Related Dinoflagellates}, DOI={10.1128/AEM.66.11.4641-4648.2000}, abstractNote={ABSTRACT Pfiesteria complex species are heterotrophic and mixotrophic dinoflagellates that have been recognized as harmful algal bloom species associated with adverse fish and human health effects along the East Coast of North America, particularly in its largest (Chesapeake Bay in Maryland) and second largest (Albermarle-Pamlico Sound in North Carolina) estuaries. In response to impacts on human health and the economy, monitoring programs to detect the organism have been implemented in affected areas. However, until recently, specific identification of the two toxic species known thus far, Pfiesteria piscicida and P. shumwayae (sp. nov.), required scanning electron microscopy (SEM). SEM is a labor-intensive process in which a small number of cells can be analyzed, posing limitations when the method is applied to environmental estuarine water samples. To overcome these problems, we developed a real-time PCR-based assay that permits rapid and specific identification of these organisms in culture and heterogeneous environmental water samples. Various factors likely to be encountered when assessing environmental samples were addressed, and assay specificity was validated through screening of a comprehensive panel of cultures, including the two recognized Pfiesteria species, morphologically similar species, and a wide range of other estuarine dinoflagellates. Assay sensitivity and sample stability were established for both unpreserved and fixative (acidic Lugol's solution)-preserved samples. The effects of background DNA on organism detection and enumeration were also explored, and based on these results, we conclude that the assay may be utilized to derive quantitative data. This real-time PCR-based method will be useful for many other applications, including adaptation for field-based technology.}, number={11}, journal={Applied and Environmental Microbiology}, author={Bowers, Holly A. and Tengs, Torstein and Glasgow, Howard B. and Burkholder, JoAnn M. and Rublee, Parke A. and Oldach, David W.}, year={2000}, month={Nov} }
 @article{oldach_delwiche_jakobsen_tengs_brown_kempton_schaefer_bowers_glasgow_burkholder_et al._2000, title={Heteroduplex mobility assay-guided sequence discovery: Elucidation of the small subunit (18S) rDNA sequences of <i>Pfiesteria piscicida</i> and related dinoflagellates from complex algal culture and environmental sample DNA pools}, DOI={10.1073/pnas.97.8.4303}, abstractNote={The newly described heterotrophic estuarine dinoflagellate Pfiesteria piscicida has been linked with fish kills in field and laboratory settings, and with a novel clinical syndrome of impaired cognition and memory disturbance among humans after presumptive toxin exposure. As a result, there is a pressing need to better characterize the organism and these associations. Advances in Pfiesteria research have been hampered, however, by the absence of genomic sequence data. We employed a sequencing strategy directed by heteroduplex mobility assay to detect Pfiesteria piscicida 18S rDNA “signature” sequences in complex pools of DNA and used those data as the basis for determination of the complete P. piscicida 18S rDNA sequence. Specific PCR assays for P. piscicida and other estuarine heterotrophic dinoflagellates were developed, permitting their detection in algal cultures and in estuarine water samples collected during fish kill and fish lesion events. These tools should enhance efforts to characterize these organisms and their ecological relationships. Heteroduplex mobility assay-directed sequence discovery is broadly applicable, and may be adapted for the detection of genomic sequence data of other novel or nonculturable organisms in complex assemblages.}, number={8}, journal={Proceedings of the National Academy of Sciences}, author={Oldach, David W. and Delwiche, Charles F. and Jakobsen, Kjetill S. and Tengs, Torstein and Brown, Ernest G. and Kempton, Jason W. and Schaefer, Eric F. and Bowers, Holly A. and Glasgow, Howard B. and Burkholder, JoAnn M. and et al.}, year={2000}, month={Apr} }
 @article{levin_rezvani_christopher_glasgow_deamer-melia_burkholder_moser_jensen_2000, title={Rapid neurobehavioral analysis of Pfiesteria piscicida effects in juvenile and adult rats}, DOI={10.1016/S0892-0362(00)00080-5}, abstractNote={The estuarine dinoflagellate Pfiesteria piscicida is known to kill fish and has been associated with neurocognitive deficits in humans. We have developed a rat model to demonstrate that exposure to Pfiesteria causes significant learning impairments. This has been repeatedly seen as a choice accuracy impairment during radial-arm maze learning. Pfiesteria-induced effects were also seen in a locomotor activity test in the figure-8 apparatus. The current studies used the short-term radial-arm maze acquisition, the figure-8 activity test, and the functional observational battery (FOB) to assess Pfiesteria-induced neurobehavioral effects in adult and juvenile rats. In study 1, the neurobehavioral potency of three different Pfiesteria cultures (Pf 113, Pf 728, and Pf Vandermere) was assessed. Ninety-six (12 per group) adult female Sprague-Dawley rats were injected subcutaneously with a single dose of Pfiesteria taken from aquarium-cultured Pfiesteria (35,600 or 106,800 Pfiesteria cells per kilogram of rat body weight). One control group (N = 12) was injected with saline and one (N = 12) with aquarium water not containing Pfiesteria. All three of the Pfiesteria samples (p < 0.05) impaired choice accuracy over the first six sessions of training. At the time of the radial-arm maze choice accuracy impairment, no overt Pfiesteria-related effects were seen using an FOB, indicating that the Pfiesteria-induced choice accuracy deficit was not due to generalized debilitation. In the figure-8 apparatus, Pfiesteria treatment caused a significant decrease in mean locomotor activity. In study 2, the neurobehavioral effects of the Pf 728 sample type were assessed in juvenile rats. Twenty-four day-old male and female rats were injected with 35,600 or 106,800 Pf-728 Pfiesteria cells per kilogram of rat body weight. As with adult females, the juvenile rats showed a significant impairment in radial-arm maze choice accuracy. No changes in locomotor activity or the FOB were detected in the juvenile rats. Furthermore, there were no differences between male and female rats in the Pfiesteria-induced choice accuracy impairment. Pfiesteria effects on choice accuracy in the radial-arm maze in rats constitute a critical component of the model of Pfiesteria toxicity, because the hallmark of Pfiesteria toxicity in humans is cognitive dysfunction. Our finding that analysis of the first six sessions of radial-arm maze testing is sufficient for determining the effect means that this test will be useful as a rapid screen for identifying the critical neurotoxin(s) of Pfiesteria in future studies.}, number={4}, journal={Neurotoxicology and Teratology}, author={Levin, E.D and Rezvani, A.H and Christopher, N.C and Glasgow, H.B and Deamer-Melia, N.J and Burkholder, J.M and Moser, V.C and Jensen, K}, year={2000}, month={Jul} }
 @article{glasgow_burkholder_2000, title={Water Quality Trends and Management Implications from a Five-Year Study of a Eutrophic Estuary}, DOI={10.2307/2641015}, abstractNote={The Neuse River and Estuary, a major tributary of the second largest estuary on the United States mainland, historically has sustained excessive blooms of algae and toxic dinoflagellates, hypoxia, and fish kills. Previous attempts have been made to use short-term databases of 2–3 years, or data sets from infrequent (monthly) sampling, to assess whether nutrient inputs to the Neuse are increasing and supporting higher algal production. These previous efforts also have relied on single-point-determined flow velocity data, at upstream sites remote from the estuary, to estimate the volume of flow in quantifying nutrient loading to the estuary. We completed a five-year study of the Neuse, including a comparative inventory of nutrients to the watershed from point sources and from concentrated animal operations (CAOs) as recent nonpoint sources, as well as an intensive assessment of water quality over time in the mesohaline estuary. Estimates of nutrient loads were based on volume of flow data from shore-to-shore transect cross sections, taken with a boat-mounted acoustic Doppler current profiler at the westernmost edge of the estuary. A total of 441 point dischargers contributed at least 3.34 × 108 L effluent/d to the Neuse system, much of which came from municipal wastewater treatment plants (2.03 × 108 L effluent/d, excluding periods of plant malfunctions; total annual loadings of at least 9 × 105 kg P and 2.1 × 106 kg N, with a 17% increase in human population over the past decade). The Neuse basin also included 554 CAOs, with 76% in swine production (1.7 × 106 animals, from a 285% increase in the past decade) and 23% in poultry (5.5 × 105 animals). An estimated 5.9 × 109 kg manure produced by swine and poultry during 1998 contributed ∼4.1 × 107 kg N and 1.4 × 107 kg P to the Neuse watershed. About 20% of the area in the watershed now has enough manure from CAOs to exceed the P requirements of all nonlegume crops and forages. About two-thirds of the N- and P-rich feeds for these animals are imported (with 4.0 × 107 kg N and 1.6 × 107 kg P in 1998); thus, the watershed increasingly has become a nutrient sink. Over the five-year study in the Neuse Estuary study area, P loading significantly declined (by an estimated 14%), whereas TN (total nitrogen) loading significantly increased (by an average of 16%) and TNi (total inorganic nitrogen) increased by ∼38%. The increased inorganic N (Ni), partly related to severe storms with high precipitation in years 4–5, coincided with a decrease in phytoplankton biomass (as chlorophyll a) that likely reflected displacement/washout of algal populations and cysts. Thus, while both N and P supplies have increased in the watershed, there is evidence for a significant increase in Ni loading but, as yet, no apparent signal for increased P in the lower estuary. Weather patterns ultimately control when/whether the elevated Ni supply will support increased algal production, so that estuarine algal blooms, hypoxia, and fish kills will remain difficult, at best, to predict in modeling efforts. We recommend that decadal data sets, with sufficient sampling frequency to capture nutrient loadings from major storm events, be used to assess fluctuations in algal production of lower rivers and estuaries, and relationships with changing nutrient inputs. Given increased N and P supplies in the Neuse watershed from ongoing growth of both human and swine populations, a current management goal of 30% N reduction should be altered to include increased focus on Ni and strengthened comanagement of P. As for estuaries in other regions, nutrient reduction goals should be interpreted as "moving targets" that likely will have to be substantially adjusted upward, over time, to accomplish noticeable reductions in algal blooms, hypoxia, and fish kills in the lower Neuse River and Estuary.}, number={4}, journal={Ecological Applications}, author={Glasgow, Howard B. and Burkholder, JoAnn M.}, year={2000}, month={Aug} }
 @article{burkholder_mallin_glasgow_1999, title={Fish kills, bottom-water hypoxia, and the toxic Pfiesteria complex in the Neuse River and Estuary}, DOI={10.3354/meps179301}, abstractNote={A recent paper by Paerl et al. 'Ecosystem responses to internal and watershed organic matter loading: consequences for hypoxia in the eutrophying Neuse River Estuary, North Carolina, USA' (1998; Mar Ecol Prog Ser 166:17-25) makes the statement that increased nitrogen loading to the Neuse River Estuary has led to algal blooms which produced organic matter loads capable of causing extensive hypoxic and anoxic conditions that, in turn, have induced widespread mortality of resident finand shellfish (p l?) . In this Comment we demonstrate that Paerl et al.'s central conclusion about finfish kills is not supported either by their data or by any statistical analysis, despite invoking predictability ('Results and discussion', p 20-24, Paerl et al. 1998). The paper contains numerous misinterpretations and misuse of literature citations. Paerl et al. also made serious errors of omission, germane from the perspective of science ethics, in failing to cite peerreviewed, published information that attributed other causality to various fish kills that they described. When attempting to make the difficult step from correlation to implication of causality in a field setting, the available evidence for multiple causative factors should be considered-especially when dealing with a topic that has significant implications for policy makers, scientists, and the general public. Accordingly, formal correction of the Paerl et al. paper is necessary because of the authors' (1) lack of depth profiles of dissolved oxygen (DO) data to support any of their conclusions about kills of surface-schooling fish, (2) use of unrecorded or nonexistent fish kill data, as well as misconveyance of fish kills as reported in the State database upon which they relied, (3) apparent lack of understanding about the behavior of resident fish population~, (4) misuse of literature citations, (5) omission of a large body of peer-reviewed, published information on the same fish kills (1995-1996), and (6) lack of any supporting statistical analyses to demonstrate relationships among field dissolved oxygen, nutrient, and fish kill data. Lack of supporting dissolved oxygenlfish kill data and literature. The only DO data that Paerl et al. presented were from the bottom water. A much more complete database (laboratory of J.M.B. & H.B.G.; summary reports covering the period 1993 through 1996, available from the Division of Water Quality [DWQ] of the North Carolina Department of Environment & Natural Resources [NC DENR]) than that discussed by Paerl et al. contains information for physical, chemical, and biological factors on the mesohaline Neuse. This area (Fig. 1) includes the segments addressed in Paerl et al. and the segments where major fish kills historically have occurred in that estuary. Here we compare Paerl et al.'s contentions, based on biweekly data from 6 to 8 mainstem Neuse stations, with the data of our State-certified laboratory, including DO depth profiles. We report weekly data from 6 stations in the mainstem, mesohaline Neuse (Flanners Beach/Kennel Beach to MinnesottKherry Point), as well as data from freshwater segments following a major storm in late summer 1996. These data show that in summers of averageprecipitation years without hurricanes, hypoxic waters in the Neuse Estuary generally were constrained to the bottom third of the water column (Figs. 2 to 4 of this paper; hypoxia considered as in Paerl et al.). Paerl et al. stated that they used a fish kill database from NC DWQ (formerly the Division of Environmental Management [DEM] of the NC Department of Environment, Health & Natural Resources [NC DEHNR]) as}, number={1999 Apr. 15}, journal={Marine Ecology Progress Series}, author={Burkholder, JM and Mallin, MA and Glasgow, HB}, year={1999}, month={Jan} }
 @article{lewitus_glasgow_burkholder_1999, title={KLEPTOPLASTIDY IN THE TOXIC DINOFLAGELLATE <i>PFIESTERIA PISCICIDA</i> (DINOPHYCEAE)}, DOI={10.1046/j.1529-8817.1999.3520303.x}, abstractNote={The ichthyotoxic dinoflagellate Pfiesteria piscicida Steidinger et Burkholder has a complex life cycle with several heterotrophic flagellated and amoeboid stages. A prevalent flagellated form, the nontoxic zoospore stage, has a proficient grazing ability, especially on cryptophyte prey. Although P. piscicida zoospores lack the genetic capability to synthesize chloroplasts, they can obtain functional chloroplasts from algal prey (i.e. kleptoplastidy), as demonstrated here with a cryptophyte prey. Zoospores grown with Rhodomonas sp. Karsten CCMP757 (Cryptophyceae) grazed the cryptophyte population to minimal densities. After placing the cultures in near darkness where cryptophyte recovery was restricted and further prey ingestion did not occur, the time‐course patterns in growth, prey chloroplast content·zoospore −1 , and prey nucleus content·zoospore −1 were followed. Ingested chloroplasts were selectively retained in the dinoflagellate, as indicated by the decline and, ultimately, near absence of cryptophyte nuclei in plastid‐containing zoospores. Chloroplasts retained inside P. piscicida cells for at least a week were photosynthetically active, as indicated by starch accumulation and microscope‐autoradiographic measurements of bicarbonate uptake. Recognition that P. piscicida can function as a phototroph broadens our perspective of the physiological ecology of the dinoflagellate because it suggests that, at least during part of its life cycle, P. piscicida ’s growth and survival might be affected by photoregulation and nutritional control of photosynthesis.}, number={2}, journal={Journal of Phycology}, author={Lewitus, Alan J. and Glasgow, Howard B. and Burkholder, JoAnn M.}, year={1999}, month={Apr} }
 @article{lewitus_willis_hayes_burkholder_glasgow_glibert_burke_1999, title={MIXOTROPHY AND NITROGEN UPTAKE BY <i>PFIESTERIA PISCICIDA</i> (DINOPHYCEAE)}, DOI={10.1046/j.1529-8817.1999.3561430.x}, abstractNote={The nutritional versatility of dinoflagellates is a complicating factor in identifying potential links between nutrient enrichment and the proliferation of harmful algal blooms. For example, although dinoflagellates associated with harmful algal blooms (e.g. red tides) are generally considered to be phototrophic and use inorganic nutrients such as nitrate or phosphate, many of these species also have pronounced heterotrophic capabilities either as osmotrophs or phagotrophs. Recently, the widespread occurrence of the heterotrophic toxic dinoflagellate, Pfiesteria piscicida Steidinger et Burkholder, has been documented in turbid estuarine waters. Pfiesteria piscicida has a relatively proficient grazing ability, but also has an ability to function as a phototroph by acquiring chloroplasts from algal prey, a process termed kleptoplastidy. We tested the ability of kleptoplastidic P. piscicida to take up 15 N‐labeled NH , NO , urea, or glutamate. The photosynthetic activity of these cultures was verified, in part, by use of the fluorochrome, primulin, which indicated a positive relationship between photosynthetic starch production and growth irradiance. All four N substrates were taken up by P. piscicida , and the highest uptake rates were in the range cited for phytoplankton and were similar to N uptake estimates for phagotrophic P. piscicida . The demonstration of direct nutrient acquisition by kleptoplastidic P. piscicida suggests that the response of the dinoflagellate to nutrient enrichment is complex, and that the specific pathway of nutrient stimulation (e.g. indirect stimulation through enhancement of phytoplankton prey abundance vs. direct stimulation by saprotrophic nutrient uptake) may depend on P. piscicida ’s nutritional state (phagotrophy vs. phototrophy).}, number={6}, journal={Journal of Phycology}, author={Lewitus, Alan J. and Willis, Bonnie M. and Hayes, Kenneth C. and Burkholder, JoAnn M. and Glasgow, Howard B., Jr. and Glibert, Patricia M. and Burke, Marianne K.}, year={1999}, month={Dec} }
 @article{levin_simon_schmechel_glasgow_deamer-melia_burkholder_moser_jensen_harry_1999, title={Pfiesteria Toxin and Learning Performance}, DOI={10.1016/S0892-0362(98)00041-5}, abstractNote={Pfiesteria piscicida is an estuarine dinoflagellate involved with fish kills along the east coast of the United States. We previously documented a radial-arm maze learning deficit in rats exposed to Pfiesteria that may be related to cognitive deficits seen in humans after accidental Pfiesteria exposure. The current study elucidated important behavioral parameters of this deficit. There were six dose groups. Forty (10/group) adult female Sprague–Dawley rats were injected (SC) with a single dose of Pfiesteria taken from aquarium-cultured Pfiesteria (35,600, 106,800, or 320,400 Pfiesteria cells/kg of rat body weight or a cell-free filtrate of the 106,800 cells/kg dose). One control group (N = 10) was injected with saline and one (N = 10) with aquarium water not containing Pfiesteria. Half of the rats in each group were tested on an 8-arm radial maze in a standard test room, and the other half were tested on the radial maze in a sound-attenuating chamber. In the standard maze room, there was a significant effect of Pfiesteria (p < 0.05) impairing choice accuracy improvement over the first six sessions of training among rats administered 106,800, 320,400, and the 106,800 cells/kg filtered sample. In contrast, there was no indication of an effect of Pfiesteria when the rats were tested on the same configuration radial maze in the sound-attenuating chamber. After 18 sessions of training in one room, the rats were switched for six sessions of testing in the other room and finally were switched back to their original room for three sessions. There was a significant Pfiesteria-induced deficit when the rats were tested in the standard test room but not when they were tested in the sound-attenuating chamber. When the Pfiesteria-exposed rats were initially switched from the sound-attenuating chamber to the standard test room they performed significantly worse than controls, whereas Pfiesteria-treated rats switched from the standard test room to the sound-attenuating chamber did not perform differently from controls. These results suggest that the Pfiesteria-induced learning impairment may result from the negative impact of distracting stimuli. At the time of the learning impairment, no overt Pfiesteria-related effects were seen using a functional observational battery and no overall response latency effects were seen, indicating that the Pfiesteria-induced choice accuracy deficit was not due to generalized debilitation. In the initial use of the figure-8 maze in this line of research, the rats in the same Pfiesteria treatment groups that showed significant deficits in the radial-arm maze showed greater declines in activity rates in a 1-h figure-8 locomotor activity test. Both the 106,800 and 320,400 Pfiesteria cells/kg groups showed significantly greater linear trends of activity decline relative to tank water-treated controls. This reflected an initial slight hyperactivity in the Pfiesteria-treated animals followed by a decrease to control levels. Pfiesteria effects in the figure-8 maze and in early radial-arm maze training may be useful in a rapid screen for identifying the critical toxin(s) of Pfiesteria in future studies. Published by Elsevier Science Inc.}, number={3}, journal={Neurotoxicology and Teratology}, author={Levin, E.D and Simon, B.B and Schmechel, D.E and Glasgow, H.B and Deamer-Melia, N.J and Burkholder, J.M and Moser, V.C and Jensen, K and Harry, G.J}, year={1999}, month={May} }
 @article{fairey_edmunds_deamer-melia_glasgow_johnson_moeller_burkholder_ramsdell_1999, title={Reporter Gene Assay for Fish-Killing Activity Produced by Pfiesteria piscicida}, DOI={10.2307/3434655}, abstractNote={Collaborative studies were performed to develop a functional assay for fish-killing activity produced by Pfiesteria piscicida. Eight cell lines were used to screen organic fractions and residual water fraction by using a 3-[4, 5-dimethylthiazol-(2-4)]-diphenyltetrazolium bromide cytotoxicity assay. Diethyl ether and a residual water fraction were cytotoxic to several cell lines including rat pituitary (GH(4)C(1)) cells. Residual water as well as preextracted culture water containing P. piscicida cells induced c-fos-luciferase expressed in GH(4)C(1) cells with a rapid time course of induction and sensitive detection. The reporter gene assay detected activity in toxic isolates of P. piscicida from several North Carolina estuaries in 1997 and 1998 and may also be suitable for detecting toxic activity in human and animal serum.}, number={9}, journal={Environmental Health Perspectives}, author={Fairey, Elizabeth R. and Edmunds, J. Stewart G. and Deamer-Melia, Nora J. and Glasgow, Howard and Johnson, Frank M. and Moeller, Peter R. and Burkholder, JoAnn M. and Ramsdell, John S.}, year={1999}, month={Sep} }
 @article{burkholder_glasgow_1999, title={Science Ethics and its Role in Early Suppression of the Pfiesteria Issue}, DOI={10.17730/humo.58.4.976098q356672751}, number={4}, journal={Human Organization}, author={Burkholder, JoAnn and Glasgow, Howard}, year={1999}, month={Dec} }
 @inproceedings{glasgow_lewitus_burkholder_1998, title={Feeding behavior of the icthyotoxic estuarine dinoflagelate pfiesteria piscicida on amino acids, algal prey, and fish vs. mammalian erythrocytes}, booktitle={Harmful algae = Algas nocivas: Proceedings of the VIII International Conference on Harmful Algae, Vigo, Spain, 25-29 June 1997}, publisher={Vigo, Spain: Intergovernmental Oceanographic Commission  of Unesco}, author={Glasgow, H. B. and Lewitus, A. J. and Burkholder, J. M.}, year={1998}, pages={394–397} }
 @article{burkholder_larsen_glasgow_mason_gama_parsons_1998, title={Influence of Sediment and Phosphorus Loading on Phytoplankton Communities in an Urban Piedmont Reservoir}, DOI={10.1080/07438149809354114}, abstractNote={ABSTRACT The response of phytoplankton communities to an imposed gradient of sediment loading under low versus high phosphate enrichment was assessed with enclosures (2-m-diameter polyethylene columns, open to the surface and the sediment) in a small piedmont reservoir within an urbanized watershed. The experimental design included replicated controls [CON, with ambient suspended solids (SS) and phosphorus (P)] and treatments low clay (LC), a natural hydrated sediment mix, sufficient clay initially added to effect an average daily concentration of 5 mg SS L−1 d−1), high clay (HC), 15 mg SS·L−1·d−1, phosphate enrichment (PHOS), ≥ 250 μg PO4 −3 P L−1); LC+P, and HC+P, imposed for ca. 10 weeks in the summer growing season. Clay additions without P led to decreased phytoplankton production (as chlorophyll a, chla) relative to controls, with colonial blue-greens and colonial greens increasing in LC, and HC dominated by filamentous blue-greens and mixotrophic flagellates. Significant increases in chla occurred in the epilimnion and hypolimnion of the P treatment, and in the epilimnion of LC+P, and HC+P. Low variability in community response occurred in treatments with sediment loading alone, whereas the P additions imposed high variability among replicates within treatments considering both total algal production and the timing of blooms. Overall, P enrichment stimulated nuisance algal blooms whether alone or with low sediment inputs, and increased P mitigated the adverse effects of high sediment loading in supporting blue-green (cyanobacteria) blooms. Undesirable algae such as Anabaena flos-aquae and A. circinalis were able to maintain populations under high sediment loading, and may serve as an innoculum for development of noxious blooms when shallow, turbid systems experienced high P enrichment.}, number={1}, journal={Lake and Reservoir Management}, author={Burkholder, J. M. and Larsen, L. M. and Glasgow, H. B. and Mason, K. M. and Gama, P. and Parsons, J. E.}, year={1998}, month={Mar} }
 @inbook{burkholder_glasgow_lewitus_1998, title={Physiological ecology of Pfiesteria piscicida with general comments on 'ambush-oredator' dinoflagellates}, volume={41}, booktitle={Physiological ecology of harmful algal blooms}, publisher={New York: Springer}, author={Burkholder, J. M. and Glasgow, H. B. and Lewitus, A. J.}, editor={D. M. Anderson, A. D. Cembella and Hallegraeff, G. M.Editors}, year={1998}, pages={175–191} }
 @inproceedings{toffer_schaefer_glasgow_burkholder_rublee_1998, title={Ribosomal DNA from the toxic dinoflagellate pfiesteria piscicida}, booktitle={Harmful algae = Algas nocivas: Proceedings of the VIII International Conference on Harmful Algae, Vigo, Spain, 25-29 June 1997}, publisher={Vigo, Spain: Intergovernmental Oceanographic Commission  of Unesco}, author={Toffer, K. L. and Schaefer, E. F. and Glasgow, H. B. and Burkholder, J. M. and Rublee, P. A.}, year={1998}, pages={278–279} }
 @article{burkholder_glasgow_1997, title={<i>Pfiesteria piscicida</i> and other <i>Pfiesreria</i>‐like dinoflagellates: Behavior, impacts, and environmental controls}, DOI={10.4319/lo.1997.42.5_part_2.1052}, abstractNote={Toxic Pfiesteria‐ like dinoflagellates have been implicated as causative agents of major fish kills (affecting 10 3 – 10 9 fish) in estuaries and coastal waters of the mid‐Atlantic and southeastern U.S. Transformations among an array of flagellated, amoeboid, and encysted stages in the complex life cycle of the representative species, Pfiesteria piscicida, are controlled by the availability of fresh secretions, blood, or other tissues of fish prey. P. piscicida also is a voracious predator on other estuarine microorganisms. Pfiesteria‐ like dinoflagellates require an unidentified substance(s) commonly found in fresh fish excreta‐secreta to initiate toxin production. P. piscicida is lethal to fish at low cell densities (>250–300 cells ml −1 ), and at sublethal levels (∼100–250 cells m1 −1 ) it has been shown to cause ulcerative fish diseases. P. piscicida also has been linked to serious human health impacts. This dinoflagellate is eurythermal and euryhaline, with optima for toxic activity by the most lethal stage (toxic zoospores, TZs) at ≥26°C and 15 psu, respectively. Thus far it has shown no light optimum and is capable of killing fish at any time during a 24‐h cycle. In warmer waters (≥ 15°C) flagellated stages predominate while fish are dying, whereas amoebae predominate in colder conditions and when fish are dead. Nutritional stimuli influencing P. piscicida are complex; inorganic phosphate apparently can directly stimulate TZs, whereas inorganic phosphate and nitrate indirectly promote increased production of nontoxic zoospores (NTZs, maintained in the absence of live fish, as potential precursors to lethal TZs) by stimulating their algal prey. Organic phosphate (P o ) and nitrogen are taken up by P. piscicida osmotrophically, and P o is stimulatory to both TZs and NTZs. The available data point to a critical need to characterize the chronic and acute impacts of toxic Pfiesteria‐ like dinoflagellates on fish and other targeted prey in estuarine and coastal waters that are adversely affected by cultural eutrophication.}, number={5 pt.2}, journal={Limnology and Oceanography}, author={Burkholder, JoAnn M. and Glasgow, Howard B.}, year={1997}, month={Jul} }
 @article{mallin_burkholder_mciver_shank_glasgow_touchette_springer_1997, title={Comparative Effects of Poultry and Swine Waste Lagoon Spills on the Quality of Receiving Streamwaters}, DOI={10.2134/jeq1997.00472425002600060023x}, abstractNote={Abstract During July 1995, a poultry waste lagoon ruptured in Duplin County, North Carolina, sending 32.6 million L of chicken waste effluent into a nearby creek and the Northeast Cape Fear River. In August 1995 a breach of a hog waste lagoon released approximately 7.6 million L of waste into a system of blackwater creeks in Brunswick County, North Carolina. The poultry waste spill occurred under high rainfall‐high river flow conditions, while the swine waste lagoon spill occurred during dry conditions. Both spills caused high turbidity and low dissolved oxygen (DO) in receiving waters, and DO levels in the Northeast Cape Fear River displayed a “sag curve” 10 d after the poultry waste spill, reaching a minimum of 1.0 mg L −1 90 km downstream. Both spills delivered high N loads to receiving waters (maxima of 92.1 mg L −1 from the poultry spill and 47.0 mg L −1 from the swine waste spill). Phosphorous concentrations reached 6.0 and 11.5 mg L −1 in receiving waters of the poultry and swine waste spills, respectively. Dense phytoplankton blooms (>100 µg chlorophyll a L −1 ) were measured in the blackwater creeks after the swine spill. High fecal coliform concentrations were delivered by both spills, and concentrations of the pathogenic bacterium Clostridium perfringens ranged up to 40 000 colony‐forming units (CFU) mL −1 in the receiving waters after the poultry spill. In 1995 and 1996 more than 30 animal waste lagoon breaches, overtoppings, and inundations were reported in North Carolina, demonstrating the major pollution potential of these treatment systems.}, number={6}, journal={Journal of Environmental Quality}, author={Mallin, Michael A. and Burkholder, JoAnn M. and McIver, Matthew R. and Shank, G. Christopher and Glasgow, Howard B. and Touchette, Brant W. and Springer, Jeffrey}, year={1997}, month={Nov} }
 @article{burkholder_mallin_glasgow_larsen_mciver_shank_deamer‐melia_briley_springer_touchette_et al._1997, title={Impacts to a Coastal River and Estuary from Rupture of a Large Swine Waste Holding Lagoon}, DOI={10.2134/jeq1997.00472425002600060003x}, abstractNote={Abstract We tracked a swine waste spill (4.13 × 10 7 L) into a small receiving river and estuary. After 2 d, a 29‐km freshwater segment that the wastes had traversed was anoxic, with ca. 4000 dead fish floating and hung in shoreline vegetation. Suspended solids, nutrients, and fecal coliforms were 10‐ to 100‐fold higher at the plume's edge (71.7 mg SS/L, 39.6 mg NH + 4 ‐N/L, and >1 × 10 6 cfu/100 mL, respectively; cfu, colony forming units, SS; suspended solids) than in unaffected reference sites. Elevated nutrients and an oxygen sag from the plume reached the main estuary after ca. 5 d. Increased phytoplankton production was contributed by noxious algae, Synechococcus aeruginosa and Phaeocystis globosa (10 8 and 10 6 cells/mL, respectively) after 7 to 14 d. The toxic dinoflagellates, Pfiesteria piscicida and a second Pfiesteria ‐like species, increased to potentially lethal densities (10 3 cells/mL) that coincided with a fish kill and ulcerative epizootic. After 14 d, water‐column fecal coliforms generally were at 10 2 to 10 3 cfu/100 mL. But where the plume had hovered for the first 5 d, surface sediments mostly yielded ≥10 4 cfu/100 mL slurry, and after 61 d densities in surficial sediments were still at 10 3 to 10 4 cfu/100 mL. Dinoflagellate and euglenoid blooms developed and moved downestuary, where they were detected after 61 d. This study documented acute impacts to surfacewaters from a concentrated swine operation, and examined some environmental policies affecting the intensive animal operation industry.}, number={6}, journal={Journal of Environmental Quality}, author={Burkholder, JoAnn M. and Mallin, Michael A. and Glasgow, Howard B. and Larsen, L. Michael and McIver, Matthew R. and Shank, G. Christopher and Deamer‐Melia, Nora and Briley, David S. and Springer, Jeffrey and Touchette, Brant W. and et al.}, year={1997}, month={Nov} }
 @article{levin_schmechel_burkholder_glasgow_deamer-melia_moser_harry_1997, title={Persisting Learning Deficits in Rats after Exposure to Pfiesteria piscicida}, DOI={10.2307/3433751}, abstractNote={Pfiesteria piscicida and other toxic Pfiesteria-like dinoflagellates have been implicated as a cause of fish kills in North Carolina estuaries and elsewhere. Accidental laboratory exposure of humans to P. piscicida has been reported to cause a complex syndrome including cognitive impairment. The current project was conducted to experimentally assess the possibility of cognitive effects of P. piscicida exposure in rats. Samples of water from aquaria in which P. piscicida zoospores were killing fish were frozen, a procedure that has been found to induce encystment. Thawed samples were injected into albino Sprague-Dawley rats. A significant learning impairment was documented in rats administered samples of P. piscicida that were recently frozen. Prolonged storage of Pfiesteria samples diminished the effect. No effect was seen in the recall of a previously learned task, but when the rats were called upon to learn a new task, the Pfiesteria-treated animals showed a significant learning deficit. This effect persisted up to at least 10 weeks after a single injection of Pfiesteria. The Pfiesteria-induced learning deficit did not seem to be associated with any obvious debilitation or health impairment of the exposed rats. Deficits in habituation of arousal and rearing behavior were detected using a functional observational battery. No Pfiesteria-induced effects on blood count and white cell differential or in a standard pathological screening of brain, liver, lung, kidney, and spleen tissue were seen at 2 months after exposure. These studies document a persistent learning impairment in rats after exposure to the dinoflagellate P.piscicida in otherwise physically well-appearing rats. This effect may partially model the symptoms of cognitive impairments that humans have shown after Pfiesteria exposure.}, number={12}, journal={Environmental Health Perspectives}, author={Levin, Edward D. and Schmechel, Donald E. and Burkholder, JoAnn M. and Glasgow, Howard B. and Deamer-Melia, Nora J. and Moser, Virginia C. and Harry, G. Jean}, year={1997}, month={Dec} }
 @article{burkholder_glasgow_1997, title={Trophic Controls on Stage Transformations of a Toxic Ambush‐Predator Dinoflagellate<sup>1</sup>}, DOI={10.1111/j.1550-7408.1997.tb05700.x}, abstractNote={ABSTRACT. The toxic dinoflagellate, Pfiesteria piscicida , was recently implicated as the causative agent for about 50% of the major fish kills occurring over a three‐year period in the Albemarle‐Pamlico Estuarine System of the southeastern USA. Transformations between life‐history stages of this dinoflagellate are controlled by the availability of fresh fish secretions or fish tissues, and secondarily influenced by the availability of alternate prey including bacteria, algae, microfauna, and mammalian tissues. Toxic zoospores of P. piscicida subdue fish by excreting lethal neurotoxins that narcotize the prey, disrupt its osmoregulatory system, and attack its nervous system. While prey are dying, the zoospores feed upon bits of fish tissue and complete the sexual phase of the dinoflagellate life cycle. Other stages in the complex life cycle of P. piscidia include cryptic forms of filose, rhizopodial, and lobose amoebae that can form within minutes from toxic zoospores, gametes, or planozygotes. These cryptic amoebae feed upon fish carcasses and other prey and, thus far, have proven less vulnerable to microbial predators than flagellated life‐history stages. Lobose amoebae that develop from toxic zoospores and planozygotes during colder periods have also shown ambush behavior toward live fish. In the presence of abundant flagellated algal prey, amoeboid stages produce nontoxic zoospores that can become toxic and form gametes when they detect what is presumed to be a threshold level of a stimulatory substance(s) derived from live fish. The diverse amoeboid stages of this fish “ambush‐predator” and at least one other Pfiesteria ‐like species are ubiquitous and abundant in brackish waters along the western Atlantic and Gulf Coasts, indicating a need to re‐evaluate the role of dinoflagellates in the microbial food webs of turbid nutrient‐enriched estuaries.}, number={3}, journal={Journal of Eukaryotic Microbiology}, author={BURKHOLDER, JOANN M. and GLASGOW, HOWARD B.}, year={1997}, month={May} }
 @article{burkholder_noga_hobbs_glasgow_1992, title={New 'phantom' dinoflagellate is the causative agent of major estuarine fish kills}, DOI={10.1038/358407a0}, abstractNote={A worldwide increase in toxic phytoplankton blooms over the past 20 years has coincided with increasing reports of fish diseases and deaths of unknown cause. Among estuaries that have been repeatedly associated with unexplained fish kills on the western Atlantic Coast are the Pamlico and Neuse Estuaries of the southeastern United States. Here we describe a new toxic dinoflagellate with 'phantom-like' behaviour that has been identified as the causative agent of a significant portion of the fish kills in these estuaries, and which may also be active in other geographic regions. The alga requires live finfish or their fresh excreta for excystment and release of a potent toxin. Low cell densities cause neurotoxic signs and fish death, followed by rapid algal encystment and dormancy unless live fish are added. This dinoflagellate was abundant in the water during major fish kills in local estuaries, but only while fish were dying; within several hours of death where carcasses were still present, the flagellated vegetative algal population had encysted and settled back to the sediments. Isolates from each event were highly lethal to finfish and shellfish in laboratory bioassays. Given its broad temperature and salinity tolerance, and its stimulation by phosphate enrichment, this toxic phytoplankter may be a widespread but undetected source of fish mortality in nutrient-enriched estuaries.}, number={6385}, journal={Nature}, author={Burkholder, JoAnn M. and Noga, Edward J. and Hobbs, Cecil H. and Glasgow, Howard B.}, year={1992}, month={Jul} }