Tampa Bay Study: Seagrass Productivity Data

Home | Tampa Bay Study | Data | Task 5: Benthic Habitats - Seagrass Productivity

Seagrasses are one of the primary indicators of ecosystem health; therefore, seagrass research is important when evaluating the impacts of management decisions on overall estuarine condition. Seagrass losses prior to the 1980’s have been attributed to deleterious nitrogen loading, and recent seagrass recovery has been attributed to improved water quality conditions.

Seagrass community metabolism and other benthic communities has been measured at several sites in Tampa Bay. These (photosynthesis, and respiration) measurements are performed using the Submersible Habitat for Analyzing Reef Quality (SHARQ) and are determined from precise measurements of pH, temperature, salinity, and changes in dissolved oxygen and carbonate system parameters.

* For detailed descriptions of methodology see Refereed Publications below.

Photosynthesis and Respiration

Select a monitoring site to view graphs of net photosynthesis versus respiration, and net photosynthesis versus photosynthetically active radiation (PAR).

Study sites of net photosynthesis versus respiration, and net photosynthesis versus photosynthetically active radiation (PAR).

Metabolic parameters for representative substrate types in Tampa Bay.

View enlargement

** This table can also be viewed in PDF format within USGS poster in Related Links.

What is a SHARQ?

Submersible Habitat for Analyzing Reef Quality

A SHARQ is a benthic incubation chamber used to isolate a mass of water overlaying the seafloor. Changes in chemical parameters resulting from benthic metabolism can then be measured during incubation periods. Rates of metabolism are calculated from changes in key chemical parameters.

SHARQ: ubmersible Habitat for Analyzing Reef Quality

Graphs of net photosynthesis versus respiration, and net photosynthesis versus photosynthetically active radiation (PAR).

Bishop Harbor:

Intermediate Thalassia/100% Drift Algae Cover
(04/05 - 04/11/2002)

Cockroach Bay:

Dense Halodule/Decaying Drift Algae
(04/30 - 05/03/2002)

Feather Sound:

Intermediate Halodule
(05/04 - 05/06/2002)

Sand bottom
(05/06 - 05/08/2002)

100% Drift Algae (time only)
(05/09 - 05/11/2002)

Intermediate Halodule (time only)
(05/09 - 05/11/2002)

Mariposa Key:

Intermediate Thalassia
(04/19 - 04/21/2001)

Port Manatee:

Sparse Syringodium (time only)
(05/14 - 05/17-/2001)

Dense Syringodium (time only)
(05/14 - 05/17-/2001)

Terra Ceia Back Bar:

Sparse Thalassia/Deep Edge
(10/11 - 10/13/2003)

Intermediate Thalassia
(10/11 - 10/13/2003)

How does nitrogen affect seagrass health?

Nitrogen from fertilizers and other anthropogenic and natural sources finds its way into local water bodies through stormwater run-off, riverine input, and groundwater. Nitrogen can cause phytoplankton, a plank-like organism that drifts in the water column to bloom. An abundance of phytoplankton reduces the amount of light available to organisms on the seafloor. Since seagrass plants take root on the seafloor and require sunlight to survive, the reduction in light can limit seagrass growth.

Related Links:

USGS Open-file Report 00-166 - SHARQ Infested Waters

USGS Open-file Report 00-361 - Geochemical Productivity Monitoring in Florida Bay

USGS Open-file Report 2005-1017 - Examining the Impact of Urbanization on Seafloor Habitats

** USGS Poster - Productivity of Benthic Habitats in Tampa Bay, Florida

Refereed Publications:

* Yates, K.K. and R.B. Halley. 2003. Measuring coral reef community metabolism using a new benthic chamber technology. Coral Reefs 22 : 247-255.

Yates, K.K., C. Dufore, N. Smiley, C. Jackson, and R.B. Halley. 2007. Diurnal variation of oxygen and carbonate system parameters in Tampa Bay and Florida Bay. Marine Chemistry 104 (1-2) : 110-124.