Update 10/15/08

Pond Mud Column

It has been 10 days since I set up my Winogradsky columns. Over this time, the pond mud column has undergone some significant changes. At first, there were thin streaks of black scatter throughout the brown mud in the column. I think that these streaks initiated where the carbon source (grass clippings) were mixed into the mud. As time progressed, the black color overtook the brown color of the mud in the column which can be seen in the photo above. On top of the black layer of mud below the water line, there is a light brown layer that has a slight orange layer within it. The water which was once clear is now discolored. There is also some debris suspended along the sides of the container in the water layer. At this point, there is not a significant difference between the side facing the sun and the side facing away from the sun.


River Mud Column

The changes to the river mud column are much less significant. The water in the column which was clear is now discolored with a greenish hue. Where the mud meets the water, there is a very thin layer of mud that has turned black with orange splotches. There is also orange colored debris suspended in the water. There has not been a significant change in the mud in the rest of the column.

Winogradsky Column Setup 10/05/2008

For my Winogradsky column experiment, I wanted to compare the microbial activity in the mud of the banks of a pond and a river (seen in the pictures above, respectively). With the help of my 4 year old lab assistant, I collected mud from the north bank of a small pond near my home that is bordered by farmland on one side and a recreational trail on the other. We then collected mud from the north bank of the Paulinskill River. The river is located less than a quarter of a mile from the pond and is bordered by the same recreational trail as the pond. We also collected water from both the pond and the river.

The protocol that I used to set up my Winogradsky column was: http://www.personal.psu.edu/faculty/j/e/jel5/biofilms/winogradsky.html.

I also watched a video demonstration before constructing my column found at: http://quest.nasa.gov/projects/astrobiology/fieldwork/lessons/demo.html.

The pond mud column was constructed first. Small stones and sticks were removed from the pond mud. Then, a generous amount (about 1 cup) of grass clippings were mixed into the mud as a carbon source. Magnesium sulfate (about 1 tablespoon) was mixed into the mud as a sulfur source. Water was added to the mud mixture to give it a slightly smoother consistency (similar to heavy cream). The mud mixture was then added to a 1-liter bottle with the top cut off until the container was about 3/4 full. As the mud mixture was added, I tapped the bottle on the counter to reduce air bubbles as much as possible. Water was added to the top of the column and the bottle was covered with plastic wrap and secured with a rubber band.

Here is the finished pond mud column:

The same procedure was used to construct the river mud column. However, before constructing the column, the river mud had to be filtered through a mesh strainer to remove small stones, shells, and coarse sand particles. The river mud (shown below) was still quite sandy so I am not sure what kind of result this column will provide, if any. The finished column is pictured below.

I set both columns on my window sill which faces south. It gets light from morning until late afternoon. The containers were also marked to indicate which side of the column faces the sunlight.