An R package for easily calculating methane production and consumption from dynamics in isotope concentrations

Methane (CH4) is both highly reactive and a strong greenhouse gas, but measuring its rates of production (methanogenesis) and consumption (methanotrophy) remains difficult. Von Fischer and Hedin (2002) developed a 13CH4 pool dilution technique for doing so, but applying their equations can be tricky even after successfully measuring the time evolution of CH4 isotopes in the field or lab. Here we describe an open-source package designed to allow researchers to easily fit models to such isotope-dilution data, calculate best-fit methane production and consumption values, and assess uncertainty and significance in a variety of incubation contexts. This code, developed as part of the COMPASS-FME project and freely available for the statistical computing and graphics language R, includes extensive documentation on the theory and practice of such model-fitting for methane incubation. We welcome further contributions and ideas from researchers studying methane dynamics, soil trace gas fluxes, and related areas.