This dataset contains multiple files with information collected from field experiments conducted in different rivers in the province of Girona, Spain: Árbucies, Llémena, Major, and Terri. The experiments evaluated the effects of drying and wastewater treatment plant (WWTP) effluents on stream biofilm communities.The dataset includes structural, functional, and microbial abundance variables.

Structural variables include basal fluorescence (F0), photosynthetic efficiency (Yeff), chlorophyll-a concentration (Chla), and extracellular polymeric substances (EPS). Functional variables include β-glucosidase activity (Glu), leucine-aminopeptidase activity (Leu), net primary production (NPP), and community respiration (CR). Microbial abundance data were obtained through qPCR quantification of genes from ecologically significant microbial groups, including 16S rDNA (archaeal and bacterial abundance), 18S rDNA (eukaryotic abundance), and ITS rDNA (fungal abundance).

For each river, data were collected at multiple time points corresponding to different biofilm sampling events.At the start of the experiment (initial state, T0),biofilm samples were collected from artificial substrates that had been colonized in non-impacted river sections (upstream of the WWTP). Drying exposure (T1): Biofilm communities were subjected to two levels of drying (pulse and press) by placing the substrates on the river banks, and samples were collected again at the end of this period. WWTP effluent exposure (T2): Biofilm communities were subsequently exposed to wastewater effluents by relocating the artificial substrates downstream of the WWTP, and samples were collected from the impacted sections.

This dataset provides a complete record of structural, functional, and microbial abundance variables of stream biofilms under multiple environmental stressors across different rivers and sampling times.