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Spherical cells were detected in low salinity waters during a bloom of Karenia brevis in Alabama coastal waters. These balls resembled K. brevis in size and organelle appearance, contained similar concentration of brevetoxin, and occurred during ongoing K. brevis bloom. Based on the environmental conditions in which these cells were observed, we speculate that a rapid drop in salinity triggered the sphere formation in K. brevis. Brevetoxin concentrations were comparable between surface water samples containing typical and atypical cells ranging from 1 to 10 ng/mL brevetoxin-3 equivalents. Accurate identification and quantification of cell abundance in the water column is essential for routine monitoring of coastal waters, so misidentification of these spherical cells may result in significant underestimation of cell densities, and consequently, brevetoxin level. These potential discrepancies may negatively impact the quality of regulatory decisions and their impact on shellfish harvest area closures. We demonstrate that traditional monitoring based on microscopy alone is not sufficient for brevetoxin detection, and supporting toxin data is necessary to evaluate potential risk.
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Formation, Development, and Propagation of a Rare Coastal Coccolithophore Bloom
Abstract This study examines an unprecedented bloom ofEmiliania huxleyialong the California coast during the NE Pacific warm anomaly of 2014–2015. Observations of coccolithophore populations from microscopy and flow cytometry, surface current data derived from high‐frequency radar, and satellite ocean color imagery were used to track the population dynamics of the bloom in the Santa Barbara Channel. Results show a coastal bloom of mostlyE. huxleyithat reached cell concentrations up to 5.7 × 106cells per liter and a maximum spatial extent of 1,220 km2. We speculate that the rare cooccurrence of warm water, high water column stability, and an extensive preceding diatom bloom during the anomaly contributed to the development of this bloom. Flow cytometry measurements provided insight on the phases of bloom development (e.g., growth versus senescence) with calcified cells comprising up to 64% of particles containing chlorophyll a and detached‐coccolith:cell ratios ranging from 10 to >100. Lagrangian particle trajectories estimated during two nonoverlapping 48‐ and 72‐hr periods showed the changes in the surface structure of the bloom due to advection by surface currents and nonconservative biological and physical processes. Time rates of change of particulate inorganic carbon were estimated along particle trajectories, with rates ranging from −4 to 6 μmol·L−1·day−1. The approach presented here is likely to be useful for understanding the evolution of coastal phytoplankton bloom events in a general setting.
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- PAR ID:
- 10374670
- Publisher / Repository:
- DOI PREFIX: 10.1029
- Date Published:
- Journal Name:
- Journal of Geophysical Research: Oceans
- Volume:
- 124
- Issue:
- 5
- ISSN:
- 2169-9275
- Page Range / eLocation ID:
- p. 3298-3316
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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