Get Ready, Get Set Up...

(Look at me, I'm a blogger!)

Day 1:

Introduction:

I live pretty much right on the south bank of the Thames here in London, pass by it every day, and I thought that this experiment would give me a good opportunity to learn more about this river that is so important to the the city of London (please see "The Thames: an Overview," to be posted shortly). I've had experience working with a Winogradsky Column before, but always with fresh water and with other additives so I am excited to see how the slightly brackish Thames water will work. To give myself the greatest opportunity for observation, I created four columns: a control column with tap water and organic potting soil, a column with potting soil and Thames river water, a column with Thames mud and tap water, and finally a column with both Thames mud and river water. I did not supplement my columns with any additional carbon or sulfur source, as I wanted to simply observe what happened with the basic ingredients.

Materials:

- 5 2L bottles, 4 with tops cut off
- Rubber bands
- Cling film (that's plastic/saran wrap to you Americans!)
- Bucket
- Thames river mud
- Thames river water
- Organic potting soil
- Tap water c/o the city of London
- Exacto knife
- Scoop
- 125g cup

Procedure:

Thames river mud and water was collected just after low tide from the tidal flats by the Vauxhall Bridge (fig. 1), accessed by the London Duck Tours boat ramp. Using the bucket and scoop, an ample quantity of mud - enough to half fill two 2L bottles - was collected, with care being taken to not collect any river rocks or twigs. A 2L bottle was filled with water from the river. Back at my flat, the tops of four of the 2L bottles was cut off using the exacto knife, so that the four bottles were the same height. To standardize the amount of potting soil and mud that was put into the four columns, a 125g container was used to scoop.



Fig. 1 - A view of the tidal flats by the Vauxhall Bridge just after low tide. The shallow pool in the center left of the image is where the mud was collected from.







Columns A and B each received three scoops of potting soil, Columns C and D each received three scoops of Thames mud. Then, using the same container (rinsed out), liquid was added to each column. Column A received four scoops of London tap water and Column B received four scoops of Thames river water. Column C received three scoops* of London tap water and Column D received three scoops* of Thames river water. I then covered each column with cling film, securing it with two rubber bands each, (fig. 2). I then lined the columns up by my balcony-side window so they would get equal amounts of the scant London sunlight while being in a temperature-controlled environment. My protocol was based on the one found at http://www.personal.psu.edu/faculty/j/e/jel5/biofilms/winogradsky.html.








Fig. 2 - the set-up columns, pre-cling film. From left, A, B, C and D. Note the difference in the water level between A and B, and C and D, though C and D had one less scoop of water added.




(*When I went to add water to Columns C and D I found that after adding three scoops, the water level was already higher than the levels in Columns A and B (fig. 2) and so decided to stop rather than risk having the water level overflow. I hypothesize that the mud was already heavily saturated with water and so the added water rested on top rather than mixing as it did with Columns A and B).

PS - as stated, currently my columns are being kept inside, in a controlled environment. However, if they start to smell they're going to migrate to the other side of the balcony door...