After 79 days of growth I have observed significant changes in both columns and the amended and control columns are strikingly different from one another. Both columns were exposed to the same amount of sunlight and have been kept outside for weeks because of the strong odor coming from the columns, especially the amended column. I don't have access to a microscope so I can't be certain which microbes are present in my columns, but based on the patterns I see in the columns and applying what I know about different groups of microbes and their growth requirements, I can make a prediction about what types of organisms are present. I also referred to our textbook as well as a website on Winogradsky Columns in order to more accurately identify the microbes in my columns (http://www.woodrow.org/teachers/bi/2000/Winogradsky_Column/winogradsky_column.html).
Observations of the control column (just lake mud and water):
-the water layer is still very green and is populated by a lot of algae and plant growth
-there are a few places with a film floating on the top of the water but mostly the top is open water
-the water and mud level have stayed fairly constant
-the top half of the mud layer looks mostly unchanged
-the bottom half of the mud layer is very orange/rust-colored and near the bottom are orange clumps about the size of a match head
-the mud still has several air pockets throughout and some type of channels
Microbes possibly growing in the control column:-much of the green color at the top of the column is likely photosynthetic cyanobacteria and there may be some diatoms and other organisms in the water
-the top light-colored layer of the mud is rich in oxygen so the bacteria there are probably aerobic sulfide oxidizing bacteria like Beggiatoa, Thiobacillus, and Thiothrix
-below that oxygen-rich layer is an oxygen-scarce layer (the microaerophillic zone) and this is the rust-colored area meaning it's likely populated with purple nonsulfur bacteria like Rhodospirilium and Rhodopseudomonas
-below that should be the anaerobic zone, but it is difficult to see because I didn't detect any evidence of anaerobes like Chromatium or Chlorobium
-the characteristic red, green, and purple layers seem to be absent from my column, perhaps because this column is lacking an added sulfur and carbon source
Observations of the amended column (lake mud, oatmeal, and water):
-one of the most striking differences between the two columns was how the level in the amended column dropped during the last few weeks (the water and mud levels were originally level with one another and now the mud in the amended column has compacted down)
-the water layer in the amended column went from being fairly clear, to gray and cloudy, to a milky orange color, and now it's dark gray with a hint of purple
-there is a distinct rust-colored ring on the top of the water layer but some of the water evaporated so the water level is now slightly below the ring
-there is a significant biofilm on the top of this column; it's intact and stretches across the top of the water and it appears scaly and somewhat iridescent
-the odor has only become stronger with time
-the white spots throughout the mud where the oatmeal pieces are have expanded and now it appears as though there is light-colored growth in those spots
Microbes possibly growing in the amended column:
-it's interesting that there is and never has been any green growth in this column so the evidence of cyanobacteria is basically nonexistent
-I'm guessing that it was photoheterotrophs (same as in the control column) that created the rust-colored line and with the drop in the mud and water levels it's now above the water
-other colors are absent from the column; the rest of the mud is simply very dark-colored with patches of white
-the dark mud is mostly anaerobic and is likely populated with Desulfovibrio and the methanogens may be the reason for so much odor coming from this column
Overall it was really neat seeing the progression of organisms in both columns. I was shocked to see how different they are and was surprised to see more colors in the control column; several of my predictions were very different from what I actually observed.
