Old Tampa Bay Water Quality Still Poor

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Old Tampa Bay Water Quality Still Poor

2020 Water Quality Results 

Bay Managers Continue to Observe Concerning Trends in Old Tampa Bay

  • The Tampa Bay Estuary Program (TBEP) reports on water quality annually to improve management of the bay;
  • Summertime algae blooms were again observed in Old Tampa Bay;
  • Data collection was affected by the COVID-19 pandemic, resulting in missing data for the months of April and May; and,
  • Water quality in all other bay segments remained favorable for seagrass growth, a key indicator of the bay’s health.

For the sixth consecutive year, Old Tampa Bay has exceeded chlorophyll-a targets. Chlorophyll-a is a measure of microscopic algae in the water column that can contribute to shading and die-offs of seagrasses, a key indicator of water quality health. Bay managers have linked elevated chlorophyll-a levels to a harmful algal bloom of Pyrodinium bahamense. The summertime recurrence of this alga comes despite numerous investments by local partners to reduce nitrogen pollution.

Pyrodinium has puzzled those charged with protecting and restoring Tampa Bay for at least a decade, because it has not responded to traditional pollution control measures and favors the Old Tampa Bay segment. Cary Lopez, Assistant Research Scientist with the Florida Fish and Wildlife Conservation Commission (FWC), and her team have been conducting research to help bay managers understand what actions can be taken to reduce the severity of blooms in the future. Lopez describes the complex factors driving blooms as “the balance of cellular growth and cellular loss…too much growth, you’re going to have a build up of biomass that results in higher chlorophyll in Old Tampa Bay.” Her research has inspired bay managers to look at ways oysters and clams may be used to increase cellular loss through filter feeding.

The COVID-19 pandemic also caused challenges for bay managers in 2020. Scientists were unable to collect field measurements during the months of April and May, when water clarity is typically better. As a result, the yearly water quality scorecard prepared by the TBEP presents water quality trends without data from those months.

The scorecard shows that all other areas of Tampa Bay had sufficient water clarity to allow sunlight to penetrate to the bay bottom and support the growth of underwater seagrasses. Improving water quality throughout the bay has been a hallmark achievement of the TBEP, which celebrates its 30th anniversary this year. TBEP and its partners are committed to additional work in Old Tampa Bay to get this portion of Tampa Bay back on track.


The mission of the Tampa Bay Estuary Program is to build partnerships to restore and protect Tampa Bay through implementation of a scientifically sound, community-based management plan.

TBEP is a partnership of Hillsborough, Manatee, Pasco and Pinellas counties; the cities of Tampa, St. Petersburg and Clearwater; the Southwest Florida Water Management District; the U.S. Environmental Protection Agency and the Florida Department of Environmental Protection.

All images and copy can be obtained by emailing the Tampa Bay Estuary Program’s Communication and Outreach Coordinator, Joe Whalen ([email protected]).

Supporting Multimedia:

2020 Water Quality Scorecard

Scorecard Stoplight Graphic

Chlorophyll-a Results (w/Data Gaps)