I am excited to announce that my three-source, dual-isotope partitioning approach has been published at Nature Communications! The paper describes a new technique to separate one pool (e.g., total soil CO2 emissions) into its three different sources (e.g., roots, soil organic carbon, and added plant litter), but still just using two stable isotopes (e.g., 12C/13C or 14N/15N). I’ll leave the details for the paper, which is open-access, but, briefly, it hinges on adding a double-treatment, where the experimental designs are identical, except one component has a different isotopic signature in treatment A vs. treatment B. (The figure below illustrates this graphically). The R code for analysis is published with the paper, so I am hoping it will be easily accessible to people who will find it useful – I think it could be an extremely powerful tool to help advance our understanding of element cycling in systems with more than two components.
A little story behind the paper: this review process was actually a pretty great experience. All the reviewers offered constructive comments, and I really felt like the end manuscript was much stronger after going through several rounds of revisions. One funny thing about this paper is related to the fact that I came up with the method out of necessity: I needed to separate soil, biochar, and plant root-derived CO2 in my field trial, but conventional isotope partitioning couldn’t handle three sources, and I didn’t have access to the resources to partition them by adding a radioactive isotope or something like that. I remember the moment I figured it out, and excitedly scrawling it on the chalkboard in the nook at the end of the hall in Bradfield while showing my labmate. If I had just been trying to showcase a new method, I probably would not have designed a field trial – notoriously messy – to demonstrate it! In my case, though, I just needed the method in order to do the field trial, and finish my Ph.D.. Hence, I’ll be really excited to start applying this new method in my new lab, in order to answer complex and exciting questions about three-(or more!)-way interactions in biogeochemical systems at finer scales.