Biogeochemical Indicators of Watershed Integrity and Wetland Eutrophication

EPA Grant Number: R827641
Title: Biogeochemical Indicators of Watershed Integrity and Wetland Eutrophication
Investigators: Reddy, Konda R. , DeBusk, William F. , Fisher, M. M. , Graham, William M.
Current Investigators: Reddy, Konda R. , Lowe, E. F. , DeBusk, William F. , Fisher, M. M. , Graham, William M. , Prenger, Joseph P. , Keenan, L. W. , Ogram, A.
Institution: University of Florida , St. Johns River Water Management District
EPA Project Officer: Packard, Benjamin H
Project Period: October 1, 1999 through September 30, 2002
Project Amount: $639,410
RFA: Ecological Indicators (1999) RFA Text |  Recipients Lists
Research Category: Ecological Indicators/Assessment/Restoration , Aquatic Ecosystems


The central hypothesis of the proposed research is that rates of biogeochemical cycling of C, N, and P in wetlands can be used to indicate the ecological integrity of wetlands, and that the concentrations of certain forms of these elements can accurately predict the rates of ecological important processes. The objectives of the proposed research are to: (i) identify the key biogeochemical processes impacted by nutrient loading and measure the rates of these processes along the nutrient gradient. (ii) develop relationships between a "process" and its related easily measurable "indicator", (iii) determine the spatial and temporal distribution of easily measurable indicators for a test wetland ecosystem, (iv) determine the spatial variations in biogeochemical processes, and develop spatial maps for various processes to determine the extent of impact and risk assessment. and (v) validate the predictability of empirical relationships by making independent measurements of biogeochemical processes in different wetland ecosystems.


We propose to test the hypotheses presented above in the Blue Cypress Marsh Conservation Area (BCMCA) located within Upper St Johns River Basin, Florida. Some areas of the BCMCA have been impacted over the years as a result of nutrient loading from adjacent uplands. resulting in distinct nutrient and vegetation gradients. The BCMCA provides the benefit of established gradients of high-nutrient (impacted) to low-nutrient systems (unimpacted), to test the hypotheses of this proposal. The proposed research will focus on key biogeochemical processes and microbial communities regularing the fate of nutrients in the soil and overlying litter layer at various spatial and temporal scales. This will be accomplished by conducting a series of laboratory and field experiments. statistical and modeling tools will be used for analysis and synthesis of the biogeochemical process and indicator data, including: 1) descriptive statistics related to frequency distribution and central tendency of indicator values to make comparisons between areas of low and high anthropogenic impact; o) multivariate analyses to evaluate the relationship between biogeochemical indicators, biogeochemical processes and ecological integrity; 3) geostatistical analysis to compare the characteristic spatial patterns and structure of biogeochemical indicators; 4) temporal analysis of indicators in low and high-impact areas.

Expected Results:

The expected result of the first stage of this research is to confirm the utility of simple chemical measures as reliable predictors of rates of biogeochemical processes. The study will also produce statistical models describing these relationships. Such models would provide valuable research and management tools. Because these measures would be rapid and inexpensive, investigations of biogeochemical processes could be expanded providing a better understanding of these fundamental mechanisms of ecosystems.

Publications and Presentations:

Publications have been submitted on this project: View all 26 publications for this project

Journal Articles:

Journal Articles have been submitted on this project: View all 7 journal articles for this project

Supplemental Keywords:

Water quality nutrient loads, soil quality, GIS, statistical models., RFA, Scientific Discipline, Geographic Area, Water, Ecosystem Protection/Environmental Exposure & Risk, Nutrients, Environmental Chemistry, Ecosystem/Assessment/Indicators, Ecosystem Protection, State, Ecological Risk Assessment, Ecology and Ecosystems, Ecological Indicators, aquatic ecosystem, eutrophication, nutrient supply, nutrient transport, risk assessment, wetlands, wetland vegetation, biogeochemical indicators, watersheds, nutrient gradiants, ecosystem indicators, soil, vegetation gradients, nutrient cycling, water quality, aquatic ecosystems, GIS, nutrient fluxes, spatial and temporal patterns, Florida, nitrogen, statistical evaluation

Relevant Websites: Exit EPA icon

Progress and Final Reports:

  • 2000 Progress Report
  • 2001 Progress Report
  • Final Report