Date of Award

1999

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Oceanography and Coastal Sciences

First Advisor

John W. Day, Jr

Abstract

The purpose of this dissertation was to investigate the processes that control material transport in the Southeastern (SE) Everglades and exchange with Florida Bay. Specifically, the objectives were to: (1) determine the factors controlling the spatio-temporal trends in material concentration and exchange; (2) estimate the annual nutrient and carbon export from the SE Everglades; and (3) determine the relative importance of surface water, atmospheric deposition, groundwater, and intrasystem cycling as sources and losses of nutrients to the watershed. Patterns in material exchange were observed for 2.5 years in three of five major creeks draining the SE Everglades. Statistical methods were used to derive annual carbon (C), nitrogen (N), and phosphorus (P) export to Florida Bay. Finally, water and nutrient budgets were calculated for the watershed. The seasonal pulse of freshwater and the lower input in the western watershed relative to the east explained the major spatio-temporal patterns in material exchange. Approximately 99% of exports to Florida Bay occurred during the rainy season. Higher hydraulic residence time and the advection of P-rich Gulf of Mexico waters to the western Bay resulted in higher nutrient concentrations and a lower TN:TP ratio in the western-most creek relative to the eastern creeks. The SE Everglades annually exported 7.1 g C m-2, 0.46 g N m-2, and 0.007 g P m-2 to Florida Bay. The low P flux relative to other estuarine systems reflects the efficiency of Everglades ecosystem in conserving P. Atmospheric deposition was the dominant P source to the watershed. Surface water was the major N source during the wet season, but annually equaled atmospheric N deposition. Annually 20 mg P m-2 and 590 mg N m-2 were imported into the watershed from hydrologic sources (surface water, groundwater, atmospheric deposition). Annual P import roughly equaled sediment P burial (33--71 mg m-2), while sediment N burial (1890--4071 mg m-2) exceeded hydrologic import. This budget deficit may be balanced by N fixation or may be due to underestimation of groundwater flux into the watershed. Further research is needed on the contribution of groundwater and N fixation to the nutrient budget of the SE Everglades wetlands.

ISBN

9780599262324

Pages

172

DOI

10.31390/gradschool_disstheses.6925

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