2006 Progress Report: Cyanobacteria Proliferation and Eutrophication in Florida Lakes

EPA Grant Number: X832302C002
Subproject: this is subproject number 002 , established and managed by the Center Director under grant X832302
(EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).

Center: Center for Science and Policy Applications for Coastal Environments (C–SPACE)
Center Director: D'Elia, Christopher F
Title: Cyanobacteria Proliferation and Eutrophication in Florida Lakes
Investigators: Riedinger-Whitmore, Melanie , Whitmore, Thomas J
Institution: University of South Florida
EPA Project Officer: Packard, Benjamin H
Project Period: September 1, 2005 through August 31, 2008
Project Period Covered by this Report: September 1, 2005 through August 31, 2006
RFA: Targeted Research Center (2004) Recipients Lists
Research Category: Hazardous Waste/Remediation , Targeted Research

Objective:

Cyanobacterial algal blooms are common in many eutrophic lakes in Florida. Although cyanobacteria have had considerable impact on freshwater quality within the state since the mid 1900s, the timing and causes of their appearance have remained unknown because water-quality monitoring began in Florida only after 1980. This project’s researchers proposed to recover sediment cores from six eutrophic central Florida lakes and to analyze sedimented algal pigments to document the onset of cyanobacterial presence. Their goals were to track the appearance and persistence of cyanobacteria, and using existing paleolimnological data on historical water quality from these sites, to examine the relationship between cyanobacterial proliferation and eutrophication. Their objective also was to determine the water-quality conditions that promote cyanobacterial persistence and lead to a shift to cyanobacterial dominance.

Progress Summary:

Sediment cores representing approximately 100 years of deposition were recovered from Lakes Harris, Newnans, Yale, Little Jackson, Weir, and Lulu for this project. Field assistance was provided by personnel from the Land Use and Environmental Change Institute at the University of Florida. Sedimented pigment profiles indicated that cyanobacteria were present throughout the records of all six lakes. The cyanobacterial pigments oscillaxanthin and myxoxanthophyll were historically low in sediments from three study sites, Lakes Weir, Little Jackson, and Newnans, but cyanobacterial pigment concentrations increased in recent sediment deposits. Cyanobacterial pigment profiles from two lakes, Lakes Harris and Yale, showed several historic peaks in cyanobacteria, suggesting that cyanobacterial populations frequently fluctuate in these systems. Only one lake, Lake Lulu, demonstrated decreases in cyanobacterial proliferation in recent sediments. Highest cyanobacterial concentrations were found near the base of the sediment record in this lake. Peaks in cyanobacterial pigment concentrations were compared with existing paleolimnological data for inferred total phosphorus and trophic state index (TSI) to examine the relationship between water quality and cyanobacterial proliferation. Cyanobacterial population increases in most study lakes occurred when inferred TSI ranged from 51-67, and total phosphorus (TP) values ranged from 44-70 µg/L. These ranges are consistent with paleolimnological data for cyanobacterial proliferation in 14 other central Florida lakes and suggest that predictable threshold levels for shifts to cyanobacterial dominance exist. These values might serve as reference points for preventing or managing cyanobacterial dominance. The lake histories examined in this project represent four central Florida lake regions (75-08, 75-14, 75-31, and 75-33). There is some evidence that there might be regional differences in threshold values. For example, Lake Weir and Little Lake Jackson both experienced cyanobacterial increases at TSI or TP values that were considerably lower than the other lakes examined in this study. These lakes are in regions with deeply weathered and nutrient-poor watershed soils and might be more vulnerable to cyanobacterial establishment at lower threshold levels. The researchers will explore regional patterns in threshold response to cyanobacterial dominance in the next phase of this project.

Supplemental Keywords:

water, watersheds, groundwater, land, soil, marine, estuary, chemicals, toxics, PCB, heavy metals, ecosystem, restoration, terrestrial, aquatic, habitat, innovative technology, remediation, restoration, public policy, decision making, modeling, monitoring, analytical, remote sensing, Florida, FL, EPA Region 4, social science, Florida (FL), Phosphate rock mining (SIC 1475), water, orthophosphate, total phosphorus, Tampa Bay, Bishops Harbor, Cockroach Bay, sediment, pore water.,, RFA, Scientific Discipline, Water, Water & Watershed, Environmental Monitoring, Ecology and Ecosystems, Watersheds, eutrophication, coastal watershed, nutrient flux, hazardous waste, remediation, aquatic ecosystems, coastal ecosystems, GIS, water quality, watershed assessment

Relevant Websites:

http://www.stpt.usf.edu/cspace/cspace.asp Exit

Progress and Final Reports:

Original Abstract
  • 2007
  • Final

  • Main Center Abstract and Reports:

    X832302    Center for Science and Policy Applications for Coastal Environments (C–SPACE)

    Subprojects under this Center: (EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
    X832302C001 Past and Present Water Quality in Florida Coastal Waters
    X832302C002 Cyanobacteria Proliferation and Eutrophication in Florida Lakes
    X832302C003 Reactive Metal Particle Emulsions for Removal of PCBs
    X832302C004 The Social and Environmental Dimensions of Xeriscaping: A Pathway for Ameliorating Coastal Environments
    X832302C005 An Historical Perspective on the Economic and Environmental Impacts of the Phosphate Industry on the Tampa Bay Region
    X832302C006 Interfacing SWAT and PHABSIM: A Potential GIS-based Water Resource Management Tool
    X832302C007 Acquisition of Counters for Gamma-Emitting Radioisotopes
    X832302C008 Guided Surface Vehicles
    X832302C009 Science Journalism
    X832302C010 Administration and Outreach