The Use of Microcosm Studies to Determine the Effect of Sediments and Nutrients on Fecal Indicator Bacteria in Lake Water

Author(s): Kinnaman, A. ;  Surbeck, C.

Field and laboratory experiments were conducted to determine the effects of sediments and nutrients on the persistence of the fecal indicator bacteria (FIB) groups total coliforms and Escherichia coli (E. coli) in lake water using samples collected in the field and laboratory-based microcosms. Samples were collected at a discharge point of Thompson Creek into Lower Sardis Lake in northern Mississippi. Samples were tested for total coliforms, E. coli, dissolved oxygen, temperature, dissolved organic carbon, nitrate, phosphate, and phenols. Following initial sample testing, seven microcosms were created in the laboratory: (1) lake water, (2) lake water and sediment, (3) lake water and sterilized sediment, (4) sterilized lake water and sediment, (5) sterilized deionized water and sediment, (6) sterilized lake water (control),and (7) sterilized deionized water and sterilized sediment (control). Each microcosm had a function to test a different hypothesis related to whether sediment affected FIB concentrations in water and vice-versa. Samples from each microcosm were collected approximately every 12 hours for two days and 24 hours for the subsequent five days. FIB concentrations from the microcosms were plotted against time, and first-order decay constants were obtained. In addition, correlations were run between FIB decay constants and water quality parameters to assess the dependence of FIB die-off on nutrients. Preliminary results show that FIB decay rates were lower when sediment was present and that high dissolved organic carbon concentrations were associated with a temporary increase in FIB concentrations. The data found on die-off rates and on FIB dependence on nutrients is useful to determine parameters for numerical modeling in lakes.


Technical Presentations

  • Delta Water Quality
  • Delta Water and Agriculture
  • Wetlands
  • Water Quality
  • Sediments
  • Non-Point
  • Management and Sustainability
  • Wood Treatment
  • Modeling
  • Soil and Water Treatment


Responsible Site Design: Implementing Innovative Stormwater Management Strategies

The primary goal of the workshop is to create a dynamic learning experience that examines the role of stormwater management in the built environment. The workshop will focus on integrating ecologically sound water management approaches into site design. After the workshop, attendees will be familiar with the following concepts and technical issues:

  • Knowledge of the stormwater treatment chain
  • Knowledge of the impact of land use codes on stormwater management
  • Application of a design process that mitigates the effects of stormwater on-site
  • Knowledge of the relationship between land use codes and design for innovative stormwater management


For information contact:
Jessie Schmidt
Box 9680
Mississippi State, MS 39762