An epipelic algal community on air-exposed soil.
Annals of Botany

Diurnal changes in algal xanthophyll cycle and H2O2 concentration

High light activates the xanthophyll cycle and increases the production of reactive oxygen species (ROS), such as hydrogen peroxide (H2O2), but the interrelationships between these parameters is poorly understood. Using a natural freshwater community of algae comprising Euglena species, benthic Navicula diatoms, Chlamydomonas and Chlorella species, Roach et al. demonstrate diurnal variations in H2O2 levels, with a peak at midday. At this point the algae rapidly scavenge H2O2 rather than excreting it