Last Monday I began the journey to analyze my plant samples on the IRMS (isotope ratio mass spectrometer). This beast of a machine is really a scientific marvel: using what is essentially a fancy lightbulb filament and a giant magnet, it sort out the lighter isotopes from the heavier ones and counts the relative abundances of each.
The information you can get from IRMS analysis is invaluable, but the price to pay is time—with appropriate quality control, the IRMS lab manager and I can only run about eight samples a day. I have 48 samples to run now, and later this summer, I’ll have another 70 or so. So, for the last week I’ve been in and out of the IRMS lab, which is just down the hall from the research lab where I usually spend my day. Aside from troubleshooting, once the lab manager sets up the instrument it pretty much runs itself, but it takes a watchful eye to make sure all is going well. The rest of the work involved is mostly data management (excel spreadsheet stuff).
The exciting part will be the process of sorting out the isotopic differences from plant to plant and looking for patterns. Is there a specific plant species or family that tends to be isotopically heavier or isotopically lighter? Is there a noticeable difference between plants that grew further from the lake compared to plants that grew on the shoreline? Are the patterns similar to or different from other findings from the region? Answering these questions will help me interpret what my sediment core tells about past climate.
I can’t quite answer these types of questions yet—the data fresh off the IRMS still has to be processed mathematically before I can draw any conclusions. But I’m excited to be one step closer!