The response of the N-cycle to future stressors such as global warming and ocean acidification remains highly uncertain. There are evidences that increasing levels of seawater CO2 could modify the efficiency of key N-cycle processes, particularly on N2-fixation and nitrification. Changes in the spatial and temporal evolution of these two mechanisms due to ocean acidification might have implications on ocean productivity on a global scale. This infographic was presented at the Ocean Sciences Meeting 2014 in Honolulu, US. Images by NASA and Brian Wilson.