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Home | Tampa Bay Study | Data | Nutrient Fluxes

This page is archived and is no longer being maintained. Content was last updated in 2015. For current research, visit http://coastal.er.usgs.gov/.
Tampa Bay Study | Data | Task 2: Water & Sediment Quality - Biogeochemical Cycles | Nutrient Fluxes

Tampa Bay Study: Groundwater data collection sites

Tampa Bay Study: Groundwater data collection sites (View Enlargement)

Groundwater can be a major, and in some cases primary, route of water transport from land to sea. Such groundwater flow is referred to as submarine groundwater discharge (SGD). The USGS collected groundwater samples to examine biogeochemical conditions, nutrient concentrations / stoichiometry (a measure of the proportion of essential elements, such as nitrogen and phosphate), and the salinity regime to quantify the flux of fresh and saline submarine groundwater discharge (SGD) into coastal waters and calculate the SGD-derived nutrient loading into Tampa Bay.

The data suggested that water and nutrient contributions from SGD are substantial relative to those carried by rivers. In comparison to other SGD studies, rate of nutrient flux is higher, probably due to 1) high watershed population density, 2) chemically reducing conditions, and 3) high ion concentrations in fresh groundwater. The sources and quantities of SGD nutrient contributions should be considered when developing nutrient-load studies, models, and management plans. These data can improve water management decision-making in developed watersheds, such as Tampa Bay.

Why should we measure nutrient concentrations in groundwater?
Nutrient concentrations in groundwater are often considerably higher than in receiving waters. The discharge of elevated nutrient into coastal waters may contribute to eutrophication and other ecological deterioration. Eutrophication creates excessive growth of plants and causes a variety of environmental problems, such as reduced water clarity and loss of biodiversity. This is a worldwide phenomenon and perhaps one of the greatest agents of change altering our coastal waters today. Pinellas County is the most densely populated county in Florida and nutrient loads injected into bay waters from discharging groundwater may have had a large impact on the water quality of Tampa Bay.


Groundwater nutrient concentrations (metadata)

Calculations of groundwater discharge from the surficial aquifer for Pinellas Peninsula in Tampa Bay, FL (metadata)

These data sets are in ArcGIS Shapefile format. To view these files, you must have ESRI ArcGIS Software or other GIS software. A freely available lightweight version of ESRI's software is ArcGIS Explorer.


The Impact of Groundwater and Contaminants on Tampa Bay (USGS Open-File Report 2005-1015, January 2005)

Center for Coastal & Watershed Studies > Submarine Groundwater Discharge

The Tampa Bay studies in biogeochemical cycles are presented in a special volume of Marine Chemistry - an international journal for studies of all chemical aspects of the marine environment.


Swarzenski, P.W., M. Baskaran, C.S. Henderson, and K. Yates. 2007. Tampa Bay as a model estuary for examining the impact of human activities on biogeochemical processes: An introduction. Marine Chemistry 104(1-2) : 1-3.

Baskaran, M. and P.W. Swarzenski. 2007. Seasonal variations on the residence times and partitioning of short-lived radionuclides (234Th, 7Be, 210Pb) and depositional fluxes of 7Be and 210Pb in Tampa Bay, Florida. Marine Chemistry 104 (1-2) : 27-42.

Swarzenski, P.W., C. Reich, K.D. Kroeger, and M. Baskaran. 2007. Ra and Rn isotopes as natural tracers of submarine groundwater discharge in Tampa Bay, Florida. Marine Chemistry 104 (1-2) : 69-84.

Swarzenski, P.W. and M. Baskaran. 2007. Uranium distribution in the coastal waters and pore waters of Tampa Bay, Florida. Marine Chemistry 104 (1-2) : 43-57.

* Kroeger, K.D., P.W. Swarzenski, Wm.J. Greenwood, and C. Reich. 2007. Submarine groundwater discharge to Tampa Bay: Nutrient fluxes and biogeochemistry of the coastal aquifer. Marine Chemistry 104 ; 85-87.

* Data on this page are presented within this journal article.

U.S. Department of the Interior, U.S. Geological Survey, Gulf of Mexico Integrated Science
URL of this page is: http://gulfsci.usgs.gov/tampabay/data/2_biogeochemical_cycles/nfluxes.html
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