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The Occurrence and Ecology of Microorganisms Associated with Sediments and Coral Reefs: John T. Lisle

Project Title: The Occurrence and Ecology of Microorganisms Associated with Sediments and Coral Reefs
Mendenhall Fellow: John T. Lisle, (727) 803-8747, x. 3140, jlisle@usgs.gov
Duty Station: St. Petersburg, Florida
Start Date: December 30, 2001
Education: Ph.D., 1996, Public Health, University of South Florida
Research Advisors: Lisa Robbins, (727) 803-8747, x. 3002, lrobbins@usgs.gov; Joan Rose, University of South Florida, (727) 553-3928, jrose@seas.marine.usf.edu
Project Description: The coastal regions of the United States, especially in the southeast, have been extensively developed for residential, commercial and recreational uses and tourism during the past decade. Though these developments may be collectively viewed as progressive in regard to increases in different sources of revenue and job opportunities, the negative impact on the coastal fresh and marine water ecosystems have been just as dramatic. Concomitant with the increases in population along the coast are increases in the volume of non-point and point source discharges flowing into receiving streams, bays and estuaries and near shore marine waters. Increases in non-point discharges may at first appear to be contradictory due to the low precipitation rates during this same period. However, the construction of buildings on and the paving and drain-and-fill of lands that were previously wetlands or areas that naturally drained storm waters into the underlying water table, now divert a significant proportion of storm waters over these impervious surfaces and directly into the aquatic ecosystems. Additional sources of microbial contaminants along the coastal regions of Florida and especially in the Florida Keys are private septic systems that have been shown to provide input of human fecal microorganisms on a daily basis.

Urban storm water runoff has been shown to transport pathogenic and non-pathogenic microorganisms at concentrations that may be several orders of magnitude greater than that of the receiving body of water. These levels of microorganisms become a public health concern when they contaminate bathing beaches, waters used for other recreational activities and shellfish beds. Additionally, the relatively rapid vertical flow rates through porous, sandy soils and karst formations, as found in central and southern Florida, short circuit the natural filtration and purification processes and increase the probability of infiltration and contamination of aquifers used for drinking water. These sources of human-associated microorganisms have also been implicated in the establishment of microbial diseases of coral reefs.

John is using the most current molecular-based techniques (e.g., PCR, DGGE, 16S gene sequencing) to identify the bacteria and viruses found in the water column and associated with sediments in the Tampa Bay region and coral reefs in the Florida Keys. John and colleagues are working with groups (1) in the Tampa Bay Integrated Science Project to determine which microbial populations are involved in the remediation of polyaromatic hydrocarbon contamination, (2) to determine the microbial diversity associated with coastal and estuary sediments and beach sands and the transport of these colonized substrates by wave action, and (3) in the Florida Keys screening coral mucous from healthy and diseased corals for the microbial diversity and bacterial isolates that may be associated with disease pathologies.

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