Bacteria are masters at destroying human-made compounds such as herbicides and pesticides. Understanding the type of bacteria involved in this process and the mechanisms the bacteria use are essential to cleaning up contaminated environments. This project involves an investigation into how human-made herbicides are destroyed in a unique environment: The salt springs of Big Bone Lick (BBL) State Park. The organisms under study are halophiles – salt-loving bacteria that readily grow in concentrations of salt that kill most other bacteria.
2,4-dichlorophenoxyacetic acid (2,4-D) is a broad-leaf herbicide which has seen widespread use for more than 40 years. The degradation pathway of 2, 4-D by common soil bacteria is well documented (Don & Pemberton 1981). However, 2,4D degradation by halophiles, or salt tolerant bacteria, is an area with little research (Oren et al 1992). This project will study water samples taken from salty springs at Big Bone Lick (BBL) State Park in northern Kentucky, an area which probably receives low levels of 2,4D from agricultural run-off.
The objective of this project is to shed light on how human-made compounds are degraded in salty environments. Does the salty environment alter the way in which bacteria degrade 2, 4-D? Are there novel degradation pathways? Do the bacteria in these springs resemble soil bacteria, or are they unique?
There has been only one other study on 2,4D degradation and salty environments. In a highly contaminated environment Maltseva et al. (1996) showed that halophiles degrade 2, 4-D by a well-studied pathway. Our preliminary data already suggests that bacteria at Big Bone Lick State Park break down 2,4D by a different mechanism.
Undergraduate student participants have presented their work at local, regional and national conferences.