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 Surficial Aquifer Seawater Intrusion meters
Biscayne Aquifer
Tamiami Sands
Surficial Aquifer
Gray Limestone Aquifer 50
Unnamed Sands
Hawthorn Group
Seawater Intrusion
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)

12. How much P is incorporated in Biscayne Aquifer limestone?
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
Ion Exchange
CaCO3
Dissolution

13. 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

14. Phosphorus in Biscayne Aquifer Limestone

15. 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

16. Breakthrough Curves
C/Co
liters

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

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

19. Desorption

20. Geochemical Analysis

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

22. 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:
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 , Use of tritium and helium to define groundwater flow conditions in Everglades National Park. Water Resources Research, 39(9), doi: /2002WR

23. 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
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

24. PHREEQC Results

25. Western Coastline of ENP Sept. 2007
(Boyer et al. 1999)
Gulf of Mexico