Designing a Winogradsky Column
Introduction
A Winogradsky column is a micro-community designed to grow a smaller replica of a larger ecosystem. Sergi Winogradsky along with Martinus Willem Bejerink designed it when microbiology was a newly emerging science. At that time, there were few microbiological methods and most microbiologists were engaged in researching the “germ theory” of disease. Winogradsky broke away from this practice and investigated environmental by cultivating and studying microbial communities. His work furthered our understanding of microbial diversity, physiology autotrophy and environmental nutrient cycling. In particular, his efforts led to a greater understanding of sulfur and nitrogen cycling. Of particular interest in experiments that target a specific microorganism such as sulphate-reducing bacteria are the other colonies that develop around the primary bacteria and how they affect, and are affected by the changing conditions during the progression of the experiment.
Sulphate-Reducing Bacteria
Labrotory studies are underway to utilize sulphate reducing bacteria in bioremediation solutions. Sulfur contamination is of particular concern in a variety of situations. Although some environmental damage to water sources responds will to filtering using reverse osmosis or chemical treatments, other situations such as complex or fragile ecosystems do not lend themselves to remediation in these manners. At times, active treatment of sulfur-contaminated water is impractical if not impossible. In those situations, introduction of sulfur reducing bacteria poses the most effective solution to the problem. This frequently applies to both a cost and an ecological perspective. .
In other situations, sulfur reducing bacteria is the problem instead of the solution or opens up a new range of uses due to its ability to interact with metals. It can damage the linings of pipes and even the pipes themselves. Because of their ability to use cellular containment or through the accumulation of ions in the bacterial cell metals can be removed from an environment using sulfur reducing bacteria. This ability to remove and contain insoluble metal sulfides is species specific, but may prove valuable in reducing and removing hard to handle materials. Examining the layers, structures and the evolution of the interaction with the environment by viewing the sequential development of the layers and other microorganism communities in a Winogradsky Column allows us to more fully understand how these processes evolve and take shape.
In the natural environment, sulfate-reducing bacteria (SRB) are associated acid mine drainage and occur naturally in around the world in areas experiencing high levels of sulfur because of mining occupations. The blend of sulfur and associated minerals is absorbed into rainwater runoff, progresses into streams and settles down stream into lakes and pools. Sulfur runoff from mining occupations occurs around the world. In the United States, sulfur runoff is prevalent abandoned mining areas in West Virginia and Pennsylvania Sulfur concentrations occur in rural areas and in these locations are due to fertilizer runoff. The United States Geological Survey examined this in detail in its report on CHEMICAL AND ISOTOPIC COMPOSITION OF RUNOFF as part of its study on Fertilizer-Derived Uranium And Sulfur In Rangeland Soil And Runoff: A Case Study In Central Florida . Samples were analyzed from several locations in south Florida al shown in the map below.
Figure 6. Map showing locations of surface water samples collected north and west of Lake Okeechobee and described in Table IV. Abbreviations: KR, Kissimmee River; TC, Taylor Creek; FC, Fisheating Creek; C59, Canal; HPC, Harney Pond Canal; IPC, Indian Prairie Canal; C41A, Canal; NS, Nubbin Slough; MAERC, MacArthur Agro-Ecology Research Center.
The soil concentration of sulfur and other composites in the Fisheating Creek site and in a control site can be seen in the following chart.
Objectives
The objectives of this research are twofold:
- The first Objective is to provide a specific Model Microbial Ecosystem replicating the Fisheating Creek area of Southern Florida in which to grow sulfur reducing bacteria.
- The second objective is to learn about the diverse methods sulfur reducing bacteria utilize energy, how those processes occur at different aerobic and anaerobic levels and how that affects the surrounding environment.
Materials Used
Beaker
Stirrers
Test tubes
Cover
Carbon Source
Microscope slides
Creek bed sediment from the designated region
Soil Samples from the designated region
Water Samples from the designated region
Distilled water
Calcium Sulfate (CaSO) as an electron acceptor for anaerobic respiration
Procedure
- Mix 4 parts sediment, 1 part Calcium Sulfate, and 1 part soil, then water form a pourable liquid slurry
- Place carbon source in test tube(s) and tamp down if necessary
- Pour slurry over the carbon source to a 70% level;
- Add distilled water to bring the test tube level to 1cm from the top
- Place the Winogradsky column on a window sill or in other source of natural sunlight
Control Winogradsky columns can also be prepared in a like manner and placed under different lighting conditions, and/or can be prepared from alternate soil and water samples.
Results
- Observe the experiment and control test tube(s) weekly, and record any changes.
- Examine the experimental and control test tube(s) visually and microscopically for any development of sulfur reducing bacteria
- Note and investigate any other activity in the experimental and control test tube(s). Pay particular attention to the surrounding microorganisms and how they are affected by the changes to the microenvironment created when the sulfur reducing bacteria changes the environmental make up.
References
Hard, B. C., & Higgins, J. P. (2012). Bioremediation of Acid Rock Drainage Using Sulphate-Reducing Bacteria. Retrieved 11 26, 2012, from Laurentian Library: http://pdf.library.laurentian.ca/medb/conf/Sudbury03/Bacteria/66.pdf
USGS. (2009, 05 19). CHEMICAL AND ISOTOPIC COMPOSITION OF RUNOFF. Retrieved 11 25, 2012, from SOFIA - US Geological Survey: http://sofia.usgs.gov/publications/papers/uranium_and_sulfur/runoff.html
References
