Pseudo-nitzschia in the Indian River Lagoon: an Emerging Threat for Florida

The Indian River Lagoon (IRL) spans approximately one-third of the east coast of Florida and faces numerous harmful algal blooms (HABs) in virtually all areas of the lagoon. The presence of the potentially toxic diatom, Pseudo-nitzschia, has been observed at many locations in the southern IRL. Although this diatom typically blooms in the spring and fall, it has been observed year-round in many locations of the IRL. The goal of this study is to obtain a better understanding of the population dynamics of Pseudo-nitzschia in the southern IRL, and the factors that contribute to these dynamics. To achieve this, bi-monthly surface water samples were collected for 15 months from 5 locations in the southern half of the IRL. Phytoplankton cell counts have enumerated all phytoplankton present. Environmental data has been collected at all sample locations throughout the duration of the study by the Indian River Lagoon Observatory Network. Cells of Pseudo-nitzschia have been isolated and characterized through 18S Sanger sequencing. Species identification of cultures will determine the presence or absence of domoic acid producing species within the IRL. It is expected that multiple species of Pseudo-nitzschia will be present in the IRL, with some of them being toxigenic. Surface water samples and cultures have been tested for domoic acid to confirm or deny the potential threat to the IRL. This combination of environmental data and cell counts will show the community composition in relation to Pseudo-nitzschia spp. in the IRL and the parameters that may contribute to the production of domoic acid.