This past week I was able to use a small sample of the aDNA samples to take an IR profile of Icelandic soil. I was really excited to see a small peak in the part of the spectra we have been focusing on for characterizing organic content. Using the calibration curves we have developed, we were able to calculate that the soil has around 24% organic composition. That is on the higher side of what we would except to see for Icelandic soil, but makes sense given the location of the archeological site.
The next steps will be to run the same standards with the DLP Nano. The Nano covers a much shorter wavelength portion of the IR spectrum, the near-IR. We will not be able to observe the same peaks we can see with the FTIR, but hopefully we will identify others, and can ‘stitch together’ the near and mid regions. One day it would be nice to develop a cheap, arduino-controlled visible light spectra so we can cover the whole visible-to-mid IR region of the EM spectrum. I’ve looked into the design of the vis spec and I think we could do it with a sony barcode scanner and a few lenses. Dreams for the future!
I haven’t had much time to physically work on the soil platforms in the last week, but I have worked out some more of the conceptual kinks around the workflow. I feel really confident that we can do everything we want to do in terms of collecting soil metadata, now it’s just a matter of putting all the pieces together.
One piece that has just been added to the picture is using CO2 measurements as a proxy for microbial life. This would be particularly useful for the glacial forefield (a prime site for dna extractions in the future). I will be reaching out to Chris Smith for advice about how to maintain the samples while CO2 is measured.