HYPORRHEIC BIOFILM DEVELOPMENT ON ARTIFICIAL SUBSTRATE, AS A TOOL FORASSESSING TROPHIC STATUS OF AQUATIC SYSTEMS - FIRST RESULTS

To determine the relationship between biofilm characteristics and orga nic nutrient content, we investigated the development of hyporheic bio films on artificial substrata (glass slides) in the early phase of bac terial colonization (one week) in contrasting river habitats with sign ificantly different concentrations of dissolved organic carbon (DOC) a nd biodegradable and refractory DOC (BDOC and RDOC). Results suggest t hat the quality of DOC (i.e. BDOC versus RDOC content) controlled elec tron-transport system (ETS)-active bacterial abundances early in colon ization, while DOC concentrations limit biofilm development only in th e latter phase of colonization.