Natural Resource Ecology Laboratory

Experimental Notes

We often spend months or years developing methods, but when the final version goes into the published paper, all that knowledge gained by troubleshooting and trying different things is lost. Fine if you continue to work in the same system and everything continues to work, but what if someone in a different system wants to try your method? Your notes, especially on things that you tried that DIDN’T work, could be invaluable to porting a method to a new system or set of conditions. Even if a new researcher needs to try those failed steps to develop a stronger understanding of the method, your notes could provide valuable insight.

Let’s use this page as a repository for tips, tricks and things that failed—it might just help us to succeed a bit faster! An example submission is as follows:

Using Parafilm in Soil Incubations – Beware!

My Masters’ experiment involved a large (80+ 1L mason jars) soil incubation where I added soluble carbon in the form of straw leachate to the soil. I knew from preliminary experiments that these soils would respire a lot in the first few days of the incubation (at 25°C). However, the analytical demands of those first couple of days didn’t leave me enough time to open and flush every jar every 4-8 hours. So I set out to find something that would let CO2 out but keep water in. I found that standard laboratory film, Parafilm, is permeable to CO2 but not water, so I decided to cover my jars with Parafilm. What I didn’t do was calculate just how much CO2 would get out on the basis of the permeability 400 mL/m2/24 hours. Turns out not enough. The microbes produced so much gas that the Parafilm bulged out, and after just a couple days I detected the tell-tale smells of anaerobic activity. My experiment failed and I had to quit my fall classes in order to have the time to start again. The lesson: do the calculations first or don’t use Parafilm as a gas- permeable sealer!

Submitted by Shawna McMahon