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Geochemistry of phosphorus in a carbonate aquifer affected by seawater intrusion

Geochemistry of phosphorus in a carbonate aquifer affected by seawater intrusion. René M. Price (FIU) Jeremy C. Stalker (FIU) Jean L. Jolicoeur (FIU). Naples. Everglades National Park. A. 2003 Salinity contour In wells < 25 m. A’. A. A '. Sea Level. 0. Biscayne Aquifer.

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Geochemistry of phosphorus in a carbonate aquifer affected by seawater intrusion

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  1. Geochemistry of phosphorus in a carbonate aquifer affected by seawater intrusion René M. Price (FIU) Jeremy C. Stalker (FIU) Jean L. Jolicoeur (FIU)

  2. Naples Everglades National Park

  3. A 2003 Salinity contour In wells < 25 m A’

  4. A A' Sea Level 0 Biscayne Aquifer Tamiami Sands Surficial Aquifer Gray Limestone Aquifer 50 Seawater Intrusion Unnamed Sands Hawthorn Group meters 100 Hawthorn Group (Aquiclude) 300 Floridan Aquifer 1000

  5. Geochemical Parameters P, N, TOC Ca2+, Mg2+, N+, K+, Cl-, SO42-, HCO3- pH, Temp, Sal. Sites sampled in Sept. 2007 Surface water Porewater (30-60 cm) Wells (2 – 8 m)

  6. Groundwater Sampling

  7. (Boyer et al., 1999)

  8. Supersaturation (mineral precipitation) undersaturation (mineral dissolution)

  9. Ion Exchange CaCO3 Dissolution Research Question How much P is incorporated in Biscayne Aquifer limestone? What are the adsorption/desorption characteristics of P in fresh versus salty groundwater? Water-Rock Interactions

  10. P Extraction Methods 0.5 g rock Dried and weighed • Sequential Extraction • MgCl – loosely adsorbed fraction • HCl digestion followed by filtration for total P determinations • Total P determination on filter residue for organic fraction

  11. Phosphorus in Biscayne Aquifer Limestone

  12. Adsorption/Desorption cube experiments • Cube 0.2m on a side of Key Largo Limestone. • freshwater (DIW) and seawater matrix • with PO43- varying from 0 to 20μM

  13. Breakthrough Curves C/Co liters

  14. Adsorption DIW with 8 and then 20 mM of P

  15. Adsorption DIW vs. Seawater with 8 mM of PO43-

  16. Desorption

  17. Geochemical Analysis

  18. Conclusions Water Table Ocean Ion Exchange P CaCO3 Dissolution Brackish Zone Seawater Intrusion

  19. Publications • Price, R.M, and P.K. Swart, 2006, Geochemical indicators of groundwater recharge in the Surficial Aquifer System, Everglades National Park, Florida, USA, in Harmon, R.S., and Wicks, C., eds., Perspectives on karst geomorphology, hydrology, and geochemistry—A tribute volume to Derek C. Ford and William B. White: Geological Society of America Special Paper 404:251-266. • Price, R.M., P.K. Swart, and J.W. Fourqurean, 2006, Coastal groundwater discharge-an additional source of phosphorus for the oligotrophic wetlands of the Everglades, Hydrobiologia, 569:23-36. • Price, R.M, J.D. Happell, Z. Top, and P. K. Swart. 2003, Use of tritium and helium to define groundwater flow conditions in Everglades National Park. Water Resources Research, 39(9), doi:10.1029/2002WR001929.

  20. Acknowledgements • Jim Fourqurean –FIU Biology and SERC • Len Scinto-FIU SERC • Tatiana Marquez-FIU Environmental Sciences • Srikumar Roy- IIT Kharagpur, India • Kevin Cunningham-USGS • Chris Reich-USGS • Kevin Cunningham-USGS • Chris Reich-USGS • Thomas Smith III- USGS • Gordon Anderson - USGS • Vic Engel - ENP • Jana M. Newman – SFWMD Funding Provided by: South Florida Water Management District and the Southeast Environmental Research Center

  21. PHREEQC Results

  22. Western Coastline of ENPSept. 2007 (Boyer et al. 1999) Gulf of Mexico

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