Development of a logistic regression model for the prediction of toxigenic Pseudo-nitzschia blooms in Monterey Bay, California

Abstract

Blooms of the diatom genus Pseudo-nitzschia have been recognized as a public health issue in California since 1991 when domoic acid, the neurotoxin produced by toxigenic species of Pseudo-nitzschia, was first detected in local shellfish. Although these blooms are recurring and recognized hazards, the factors driving bloom proliferation remain poorly understood. The lack of longterm field studies and/or deficiencies in the scope of environmental data included within them hinders the development of robust forecasting tools. For this study, we successfully developed predictive logistic models of toxigenic Pseudo-nitzschia blooms in Monterey Bay, California, from a multi-project dataset representing 8.3 yr of sampling effort. Models were developed for year-round (annual model) or seasonal use (spring and fall-winter models). The consideration of seasonality was significant: chlorophyll a (chl a) and silicic acid were predictors in all models, but period-specific inclusions of temperature, upwelling index, river discharge, and/or nitrate provided significant model refinement. Predictive power for 'unknown' (future) bloom cases was demonstrated at ≥75% for all models, out-performing a chl a anomaly model, and performing comparably to, or better than, previously described statistical models for Pseudo-nitzschia blooms or toxicity. The models presented here are the first to have been developed from long-term (>1.5 yr) monitoring efforts, and the first to have been developed for bloom prediction of toxigenic Pseudo-nitzschia species. The descriptive capacity of our models places historical and recent observations into greater ecological context, which could help to resolve historical alternation between the implication of freshwater discharge and upwelling processes in bloom dynamics.

A marine algicidal actinomycete and its active substance against the harmful algal bloom species Phaeocystis globosa

“…Recently, data analysis using various models has been widely applied for the prediction of HABs, thereby providing a helpful tool for evaluating the relative importance of each factor in outbreak and disappearance processes (Glibert et al 2010;Lane et al 2009;McGillicuddy 2010;Raine et al 2010). However, the mechanism behind the development and decline of an individual bloom event remains incompletely understood despite the numerous studies on the relationship between HABs and environmental factors, such as temperature, light intensity, and inorganic nutrient.…”

Application of Solid Phase Adsorption Toxin Tracking (SPATT) for field detection of the hydrophilic phycotoxins domoic acid and saxitoxin in coastal California

“…comm.). Logistic regression models developed for toxigenic Pseudo-nitzschia blooms in Monterey Bay have been used to indicate the extent of potential exposure by signaling the incidence of toxigenic bloom events (Lane et al 2009), but cannot directly address toxin incidence since toxigenic blooms can vary widely in toxicity (Anderson et al 2006(Anderson et al , 2009Blum et al 2006;Lane et al 2009;Marchetti et al 2004;Trainer et al 2002). Irrespective of bloom prevalence or toxicity, SPATT affords the direct detection of DA, PST (including STX), and other phycotoxins in the water column and, as an integrative sampling tool, SPATT has the potential to signal the incidence of toxin between discrete sampling events.…”

Nutrient Loading through Submarine Groundwater Discharge and Phytoplankton Growth in Monterey Bay, CA

“…Specifically, the coupled nitrate and silica SDG fluxes in a ratio of near 1:1, provide optimal conditions for diatom-based blooms, consistent with the observed repeated occurrences of Pseudo-nitzschia blooms in NMB. 41,42 SGD phosphate fluxes are below the Redfield ratio (required, N/P 16:1; observed, N/P ∼30−75:1). Previous studies have shown that nitrogen is the limiting nutrient in NMB and phosphate is likely supplied through efficient recycling by phytoplankton and utilization of organic phosphorus compounds within this region.…”