Aquatic Sciences Meeting, Albuquerque 2001

CS15 Harmful Algal Blooms

Date: Tuesday, February 13, 2001, Time: 12:15:00 PM

Location: Cochiti/Taos

Burkholder, J, M, North Carolina State University, Raleigh, NC, USA, joann_burkholder@ncsu.edu

Glasgow, H, B, North Carolina State University, Raleigh, NC, USA, howard_glasgow@ncsu.edu

Deamer, N, J, North Carollina State University, Raleigh, NC, USA, nora_deamer@ncsu.edu

RECENT SHIFTS IN PFIESTERIA SPP. ABUNDANCE AND TOXICITY MAY BE LINKED TO ENVIRONMENTAL N: P RATIOS: STATISTICAL TRENDS FROM A DECADE OF INTENSIVE STUDY IN NORTH

Since 1991 our research team has amassed more than 480,000 biological, chemical, and physical observations within the Albemarle/Pamlico Estuary. These data represent the most intensive long-term database ever assembled for this estuarine system and have enabled us to construct a conceptual model of Pfiesteria seasonal dynamics in relation to multiple environ-mental factors, based on statistically significant interactions from trend analysis. In the Pamlico Estuary where P loading has decreased by ca. 40%, toxic Pfiesteria outbreaks have significantly declined in frequency and duration. On the basis of archived sample analysis with molecular probes that were recently developed, P decline with concomitant N:P increase has coincided with an apparent shift at Pfiesteria-related fish kills from clear dominance by P. piscicida to co-dominance by P. piscicida and P. shumwayae sp. nov. These data support laboratory experi-ments that have shown comparatively higher P stimulation of P. piscicida zoospores, and higher N stimulation of P. shumwayae. This conceptual model is guiding collaborative research in progress to construct a quantitative, predictive model of Pfiesteria spp. abundance and toxic activity.

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Aquatic Sciences Meeting, Albuquerque 2001

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