Soil-atmosphere nitrogen oxide fluxes: Effects of root disturbance

Chambers are the most common method used to sample soil-atmosphere fluxes o f trace gases. Working in tree plantations in Costa Rica and in subtropical forest in Puerto Rico, we performed controlled experiments in order to eva luate whether installation of the chamber bases into the soil affects the s oil-atmosphere flux of nitrogen oxides. Installation of chambers severed ro ots. We found a short-term disturbance effect related to chamber installati on. Fluxes of nitrogen oxides increased by as much as a factor of 4 during a period of about I month following chamber installation in the soil. Withi n 6 weeks of chamber base installation, fluxes fell to control levels. Give n the timescale of disturbance and recovery, root mortality and decompositi on is the most likely cause of the observed effect.