Many types of naturally occurring algae are present in surface waters. Certain types of algae pose drinking water concerns when present in high concentrations (blooms). Two main types of algal toxins are monitored in the Tampa Bay region: blue-green algae (cyanobacteria) and red tide.
Blue-green algae (cyanobacteria) are organisms commonly found in freshwater sources. Blue-green algae blooms in our region are commonly caused by the presence of excess nutrients, specifically phosphate and nitrogen, and rising temperatures. Excess nutrients can make their way into water sources through wastewater, stormwater runoff and agricultural runoff.
Red tide is another type of algal bloom caused by naturally occurring algae in marine waters. These algal blooms in coastal areas of Tampa Bay and the Gulf of Mexico can release toxins that can cause illness in humans, make fish or shellfish dangerous to eat, and/or result in major fish kills and death of wildlife. Although the exact triggers for red tide are not well known, the growth and movement of these blooms depends on coastal currents, wind, temperature, nutrients and salinity.
Learn more about harmful algal blooms from EPA and cyanotoxins from the AWWA.
Tampa Bay Water monitors all our sources for indicators and precursors to potential algal blooms. This serves as an early warning system to protect drinking water supplies.
We monitor our river sources for nutrients and algae, and we use ozone and biofiltration in our regional surface water treatment plant to further safeguard our drinking water from algal toxins. We have sensors and aeration in our C.W. Bill Young Regional Reservoir that minimize the potential for algae blooms. Our seawater desalination plant uses reverse osmosis, which removes red tide.
A major benefit of having such a diverse system is its flexibility. If our monitoring were to show a potential for algal blooms in one source, we would switch to other sources, such as groundwater, where algal toxins are not a concern.
