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Time-Series Sampling in Pinellas and Manatee Counties

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Scientists at the Fish and Wildlife Research Institute (FWRI) have undertaken a time-series monitoring project to try to understand when, where and under what conditions harmful algal blooms (HABs) occur. Time-series sampling provides a sequence of data collected at relatively uniform intervals over long periods of time. With these data, scientists can better understand how ecosystems change through time and are influenced by large climatic events such as an El Niño. As scientists learn more about algal blooms, they can use this information to help identify environmental drivers of blooms, which may aid bloom forecasting.

FWRI’s HAB group has been monitoring coastal waters at 10 stations along Pinellas and Manatee counties every week for more than twenty years. Originally, this sampling was conducted to detect Karenia brevis, the Florida red tide organism. Sampling has since expanded to include looking for other types of HABs. Of those stations, five recently were selected as sites for the more detailed time-series monitoring project.


Every week, scientists collect water samples and record environmental data, such as weather and tidal conditions, from Clearwater Pass, Redington Pier, Skyway Fishing Pier, Anna Maria Island and Palma Sola Bay. They measure each water sample’s salinity, temperature, dissolved oxygen, pH (acidity) and nutrient concentrations. Samples are then transported to the FWRI lab where scientists use microscopes to identify and count the different phytoplankton species, harmful and nonharmful, recording phytoplankton biomass (amount present) and community composition (types present). The five sampling sites have different geographical dynamics (e.g., piers, mouths of rivers or marine coastlines), providing scientists another point of evaluation. By comparing data collected from geographically different sample sites, scientists can gain an even better understanding of environmental conditions favorable to blooms. They can also piece together a better picture of bloom dynamics, including size, duration and movements.

With this time-series project, researchers document short- and long-term changes in phytoplankton communities. By collecting more comprehensive environmental data, they can link changes in conditions – such as salinity, temperature or nutrient concentration – to the occurrence or disappearance of a HAB organism. Understanding why a HAB is not present is just as important as knowing why one is present. Scientists can use this information to understand when, where and under what conditions HABs occur. With that understanding, FWRI’s HAB group can alert appropriate agencies and the general public of the potential for HAB formation, allowing them to take any necessary precautions.