Figure 1.

Above: Schematic diagram of the desiccation chamber. Moist glass fiber filters with algal cells on top were positioned on a perforated metal grid on top of four glass columns inside a transparent 200 mL polystyrol box, which was filled with 100 g silica gel and sealed with a transparent top lid. A mini data logger for air humidity and temperature was employed inside the boxes on top of the silica gel for continuous measurements. The PAM light probe was positioned outside the cover lid of the box (∼2 mm distance), so that all fluorescence measurements were done through the polystyrol lid. Below: Course of the relative air humidity (RAH) conditions inside the desiccation chambers after onset of an experiment. A PCE-MSR145S-TH mini data logger for air humidity and temperature was employed inside the boxes for continuous measurements (PCE Instruments).