Reference no: EM133288776

Introductory Biogeochemistry

Assignment - Winogradsky column

You will be given the regularly scheduled class period on Sept. 23rd to assemble this project. It will have to be incubated for a minimum of 8 weeks.

For this assignment, you will construct one or more Winogradsky columns, a kind of self- contained ‘windowsill ecosystem.' In time, these will display some of the things that we will be discussing later in the course. For instructions on assembling your Winogradsky column.

You will need to find a source where you can collect some aquatic sediments, such as a pond, creek or riverbank. I recommend that you use shredded newspaper for a carbon source, a smashed hardboiled egg yolk for a sulfur source, and that you also smash and include the eggshell. During incubation, these columns will really benefit from having a lamp shone at them at fairly close range (e.g., 10 cm away).

You are only required to construct a single column, but it can be interesting to construct more than one and to see how they develop differently if you alter one of the conditions: for instance, cover one with foil to block incoming light, but leave the other exposed to light. Or, change the salinity of one by adding some salt. Even with a single column, you may be able to try things like using masking tape to keep a portion of the column in darkness.

Take notes on your set up, such as the source of your mud, the quantity of newspaper added, what are the constituents of each layer & how the layers differ from each other, etc.

Take a photo or colour a sketch and make notes on your column(s) at weekly intervals for a minimum of 8 weeks.

Write a 500+ word summary of the development of your column(s) and what insights you are able to derive from it. Include your photos showing the development of your column(s) along with your write-up. You should discuss the distribution of oxygen, of sulfur, and of carbon within the column(s). What factors are responsible for producing the chemical gradients that exist within your column(s)? If you set up multiple columns, or manipulated certain variables, discuss how the columns developed similarly or differently.

Note that the columns might produce an odour, especially during the first few weeks; if you are able, you may want to keep them outside until the weather cools off. You may not want to reuse the container at the end, so a disposable option might be a good idea.

Attachment:- Biogeochemistry.rar