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Open-File Report 2009–1203

Prepared in collaboration with the South Florida Water Management District

Preliminary Use of Uric Acid as a Biomarker for Wading Birds on Everglades Tree Islands, Florida, United States

By Anne L. Bates,1 William H. Orem,1 Susan Newman,2 Dale E. Gawlik,3 Harry E. Lerch,1 Margo D. Corum,1 and Monica Van Winkle1

1 U.S. Geological Survey, 956 National Center, Reston, VA 20192, USA.
2 South Florida Water Management District, 3301 Gun Club Road, West Palm Beach, FL 33406, USA.
3 Department of Biological Sciences, Florida Atlantic University, Boca Raton, FL 33431, USA.

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Concentrations of organic biomarkers and concentrations of phosphorus in soil cores can potentially be used as proxies for historic population densities of wading birds on tree islands in the Florida Everglades. This report focuses on establishing a link between the organic biomarker uric acid found in wading bird guano and the high phosphorus concentrations in tree island soils in the Florida Everglades. Uric acid was determined in soil core sections, in surface samples, and in bird guano by using a method of high-performance liquid chromatography-mass spectrometry (HPLC-MS) developed for this purpose. Preliminary results show an overall correlation between uric acid and total phosphorus in three soil cores, with a general trend of decreasing concentrations of both uric acid and phosphorus with depth. However, we have also found no uric acid in a soil core having high concentrations of phosphorus. We believe that this result may be explained by different geochemical circumstances at that site.

First posted January 2010

For additional information contact:
William H. Orem
U.S. Geological Survey
Mail Stop 956
12201 Sunrise Valley Drive
Reston, VA 20192

G. Ronnie Best
Program Coordinator
U.S. Geological Survey
Priority Ecosystems Studies Program
3205 College Ave.
Ft. Lauderdale, FL 33314-7799

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Suggested citation:
Bates, A.L., Orem, W.H., Newman, Susan, Gawlik, D.E., Lerch, H.E., Corum, M.D., and Van Winkle, Monica, 2010, Preliminary use of uric acid as a biomarker for wading birds on Everglades tree islands, Florida, United States: U.S. Geological Survey Open-File Report 2009–1203, 26 p., available online at

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