 radicals (OH). Under certain conditions, this molecule reacts with atmospheric oxygen (O2) to form ozone (O3), one of the gases responsible for the greenhouse effect. High concentrations of ozone can irritate plant stomata, the pores used in gas exchange and transpiration. Irritation of the stomata hinders photosynthesis and the assimilation of carbon by plants.
"Furthermore, hydroxyl radicals control atmospheric oxidation of methane, another important greenhouse gas," Artaxo said. "Depending on the situation, these OH radicals can prolong or shorten the half-life of methane, with implications for the balance of greenhouse gases."
According to Artaxo, the Amazon forest was already considered the world's largest source of isoprene even before these new discoveries. "These findings reinforce the importance of this ecosystem to the regulation of the planet's tropical atmospheric chemistry," he said. "Now, we need to include the results in global climate models to see exactly what effect these new values for isoprene emissions have on the climate."