In summer 2019, we will perform our experiments about desiccation effects on biofilm structures and processes in the benthic and hyporheic zone. Matthias Pucher will investigate the effects of drying and re-wetting on microbial abundances, EPS, activity of extra-cellular enzymes, respiration, and the uptake of DOM and nutrients via hyporheic upflow reactors in the lab (see picture). For that purpose, he will sample hyporheic sediments in both intermittent and perennial stream reaches and expose them to drying for approximately 2 months. Miren Atristrain will look at the effects of drying on epilithic biofilms, including measurements of chlorophyll-a, pigment composition, and photosynthetic yield.
In addition, field sampling will be performed by three master students and four school students, who will look at changes in algae and bacteria during drying.