Timescapes of radioactive tracers in biochemistry and ecology.

This essay considers how employing radioisotopes as tracers enabled a new visualization of the timescapes of biological processes, from metabolic pathways to nutrient cycling in ecosystems. Radiolabels made visible the fluxes and flows of materials and energy in biological systems, time-bound processes that were represented spatially in maps or as sequences of chemical reactions. Examining the experimental practices behind such images shows the complexity of temporalities and physical spaces in radiotracer experiments.