@misc{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}, ISSN={["1939-5590"]}, 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. NH4+ concentrations dramatically increased (overall by ~500%) as a persistent trend regardless of attempts to control for climatic events. An increasing trend in NH4+ also was documented in an adjacent, rapidly flushed Coastal Plain estuary, the Cape Fear. The NH4+ 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 NH4+ 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{shumway_burkholder_springer_2006, title={Effects of the estuarine dinoflagellate Pfiesteria shumwayae (Dinophyceae) on survival and grazing activity of several shellfish species}, volume={5}, ISSN={["1878-1470"]}, DOI={10.1016/j.hal.2006.04.013}, abstractNote={A series of experiments was conducted to examine effects of four strains of the estuarine dinoflagellate, Pfiesteria shumwayae, on the behavior and survival of larval and adult shellfish (bay scallop, Argopecten irradians; eastern oyster, Crassostrea virginica; northern quahogs, Mercenaria mercenaria; green mussels, Perna viridis [adults only]). In separate trials with larvae of A. irradians, C. virginica, and M. mercenaria, an aggressive predatory response of three strains of algal- and fish-fed P. shumwayae was observed (exception, algal-fed strain 1024C). Larval mortality resulted primarily from damage inflicted by physical attack of the flagellated cells, and secondarily from Pfiesteria toxin, as demonstrated in larval C. virginica exposed to P. shumwayae with versus without direct physical contact. Survival of adult shellfish and grazing activity depended upon the species and the cell density, strain, and nutritional history of P. shumwayae. No mortality of the four shellfish species was noted after 24 h of exposure to algal- or fish-fed P. shumwayae (strains 1024C, 1048C, and CCMP2089) in separate trials at ≤5 × 103 cells ml−1, whereas higher densities of fish-fed, but not algal-fed, populations (>7–8 × 103 cells ml−1) induced low (≤15%) but significant mortality. Adults of all four shellfish species sustained >90% mortality when exposed to fish-fed strain 270A1 (8 × 103 cells ml−1). In contrast, adult M. mercenaria and P. viridis exposed to a similar density of fish-fed strain 2172C sustained <15% mortality, and there was no mortality of A. irradians and C. virginica exposed to that strain. In mouse bioassays with tissue homogenates (adductor muscle, mantle, and whole animals) of A. irradians and M. mercenaria that had been exposed to P. shumwayae (three strains, separate trials), mice experienced several minutes of disorientation followed by recovery. Mice injected with tissue extracts from control animals fed cryptomonads showed no response. Grazing rates of adult shellfish on P. shumwayae (mean cell length ±1 standard error [S.E.], 9 ± 1 μm) generally were significantly lower when fed fish-fed (toxic) populations than when fed populations that previously had been maintained on algal prey, and grazing rates were highest with the nontoxic cryptomonad, Storeatula major (cell length 7 ± 1 μm). Abundant cysts of P. shumwayae were found in fecal strands of all shellfish species tested, and ≤45% of the feces produced viable flagellated cells when placed into favorable culture conditions. These findings were supported by a field study wherein fecal strands collected from field-collected adult shellfish (C. virginica, M. mercenaria, and ribbed mussels, Geukensia demissa) were confirmed to contain cysts of P. shumwayae, and these cysts produced fish-killing flagellated populations in standardized fish bioassays. Thus, predatory feeding by flagellated cells of P. shumwayae can adversely affect survival of larval bivalve molluscs, and grazing can be depressed when adult shellfish are fed P. shumwayae. The data suggest that P. shumwayae could affect recruitment of larval shellfish in estuaries and aquaculture facilities; shellfish can be adversely affected via reduced filtration rates; and adult shellfish may be vectors of toxic P. shumwayae when shellfish are transported from one geographic location to another.}, number={4}, journal={HARMFUL ALGAE}, author={Shumway, Sandra E. and Burkholder, JoAnn M. and Springer, Jeffrey}, year={2006}, month={Sep}, pages={442–458} }
 @article{springer_burkholder_glibert_reed_2005, title={Use of a real-time remote monitoring network (RTRM) and shipborne sampling to characterize a dinoflagellate bloom in the Neuse Estuary, North Carolina, USA}, volume={4}, ISSN={["1878-1470"]}, DOI={10.1016/j.hal.2004.08.017}, abstractNote={The spatial-temporal distribution of a dinoflagellate bloom dominated or co-dominated by Prorocentrum minimum was examined during autumn through early spring in a warm temperate, eutrophic estuary. The developing bloom was first detected from a web-based alert provided by a network of real-time remote monitoring (RTRM) platforms indicating elevated dissolved oxygen and pH levels in upper reaches of the estuary. RTRM data were used to augment shipboard sampling, allowing for an in-depth characterization of bloom initiation, development, movement, and dissipation. Prolonged drought conditions leading to elevated salinities, and relatively high nutrient concentrations from upstream inputs and other sources, likely pre-disposed the upper estuary for bloom development. Over a 7-month period (October 2001–April 2002), the bloom moved toward the northern shore of the mesohaline estuary, intensified under favorable conditions, and finally dissipated after a major storm. Bloom location and transport were influenced by prevailing wind structure and periods of elevated rainfall. Chlorophyll a within bloom areas averaged 106 ± 13 μg L−1 (mean ± 1 S.E.; maximum, 803 μg L−1), in comparison to 20 ± 1 μg L−1 outside the bloom. There were significant positive relationships between dinoflagellate abundance and TN and TP. Ammonium, NO3−, and SRP concentrations did not decrease within the main bloom, suggesting that upstream inputs and other sources provided nutrient-replete conditions. In addition, PAM fluorometric measurements (09:00–13:00 h) of maximal PSII quantum yield (Fv/Fm) were consistently 0.6–0.8 within the bloom until late March, providing little evidence of photo-physiological stress as would have been expected under nutrient-limiting conditions. Nitrogen uptake kinetics were estimated for P. minimum during the period when that species was dominant (October–December 2001), based on literature values for N uptake by an earlier P. minimum bloom (winter 1999) in the Neuse Estuary. The analysis suggests that NH4+ was the major N species that supported the bloom. Considering the chlorophyll a concentrations during October and December and the estimated N uptake rates, phytoplankton biomass was estimated to have doubled once per day. Bloom displacement (January–February) coincided with higher diversity of heterotrophic dinoflagellate species as P. minimum abundance decreased. This research shows the value of RTRM in bloom detection and tracking, and advances understanding of dinoflagellate bloom dynamics in eutrophic estuaries.}, number={3}, journal={HARMFUL ALGAE}, author={Springer, JJ and Burkholder, JM and Glibert, PM and Reed, RE}, year={2005}, month={Mar}, pages={533–551} }
 @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}, ISSN={["0027-8424"]}, 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 OF THE UNITED STATES OF AMERICA}, author={Burkholder, J and Eggleston, D and Glasgow, H and Brownie, C and Reed, R and Janowitz, G and Posey, M and Melia, G and Kinder, C and Corbett, R and et al.}, year={2004}, month={Jun}, pages={9291–9296} }
 @article{springer_shumway_burkholder_glasgow_2002, title={Interactions between the toxic estuarine dinoflagellate Pfiesteria piscicida and two species of bivalve molluscs}, volume={245}, ISSN={["1616-1599"]}, DOI={10.3354/meps245001}, abstractNote={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. Sec- ond, 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 main- tained 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.}, journal={MARINE ECOLOGY PROGRESS SERIES}, author={Springer, JJ and Shumway, SE and Burkholder, JM and Glasgow, HB}, year={2002}, pages={1–10} }
 @article{glasgow_burkholder_morton_springer_2001, title={A second species of ichthyotoxic Pfiesteria (Dinamoebales, Dinophyceae)}, volume={40}, ISSN={["2330-2968"]}, DOI={10.2216/i0031-8884-40-3-234.1}, abstractNote={Abstract 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, HB and Burkholder, JM and Morton, SL and Springer, J}, year={2001}, month={May}, pages={234–245} }
 @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}, volume={109}, ISSN={["1552-9924"]}, DOI={10.2307/3454912}, journal={ENVIRONMENTAL HEALTH PERSPECTIVES}, author={Burkholder, JM and Glasgow, HB and Deamer-Melia, NJ and Springer, J and Parrow, MW and Zhang, C and Cancellieri, PJ}, year={2001}, month={Oct}, pages={667–679} }
 @article{mallin_burkholder_mciver_shanks_glasgow_touchette_springer_1997, title={Comparative effects of poultry and swine waste lagoon spills on the quality of receiving streamwaters}, volume={26}, ISSN={["0047-2425"]}, DOI={10.2134/jeq1997.00472425002600060023x}, abstractNote={Abstract}, number={6}, journal={JOURNAL OF ENVIRONMENTAL QUALITY}, author={Mallin, MA and Burkholder, JM and McIver, MR and Shanks, GC and Glasgow, HB and Touchette, BW and Springer, J}, year={1997}, pages={1622–1631} }
 @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}, volume={26}, ISSN={["0047-2425"]}, DOI={10.2134/jeq1997.00472425002600060003x}, abstractNote={Abstract}, number={6}, journal={JOURNAL OF ENVIRONMENTAL QUALITY}, author={Burkholder, JM and Mallin, MA and Glasgow, HB and Larsen, LM and McIver, MR and Shank, GC and Deamer-Melia, N and Briley, DS and Springer, J and Touchette, BW and et al.}, year={1997}, pages={1451–1466} }