Correct calculation of CO2 efflux using a closed-chamber linked to a non-dispersive infrared gas analyzer

1. Improved understanding of the carbon (C) cycle is essential to model future climates and how this may feedback to affect greenhouse-gas fluxes. 2 .We summarize previous work quantifying respiration rates of organic substrates and briefly discuss how advances in technology, specifically the use of chambers linked to a non-dispersive infra-red gas analyzer (NDIR), can be applied to assess carbon dynamics from short-term field measurements. This technology hastens measurement and is relatively inexpensive, enabling researchers to increase replication and investigate temporal and spatial variation. 3. We describe the theory behind calculations of CO2 efflux released through organic substrates, when using a closed-chamber linked to a NDIR. These methods can in principle be extended to any chamber-based measurement of gas fluxes, including partially closed chambers as used for soil surface CO2, nitrous oxide or methane effluxes and stem CO2 respiration, although additional assumptions may ...