Figure 2

Four BSC samples with one dominating and indicated species each. Reactivation of net photosynthesis (open circles) and dark respiration (black squares) by high air humidity (related to surface area). Dry crusts were exposed to air with a relative humidity of 96% for 72 hours at 15°C in darkness with short cycles of illumination with 200 μmol photons/m² · s PAR. After 72 hours, samples were sprayed with water to saturation (vertical line) and then kept at 80% declining to 60% rel. air humidity until CO₂ exchange completely ceased with dehydration.