Pendant temperature light data loggers ua 002 64

Periphyton was colonized on glass microscope slides (76×26 mm, Thermo Scientific) which were soaked in 0.03 M HNO₃ and washed with nanopure water (18.1 MΩ•cm, Milli-Q) before use and were then placed horizontally in Plexiglas channels (86×10.4×10 cm, polymethyl methacrylate) in a flow-through system fed by water from river Chriesbach (on campus, Dübendorf, Switzerland) [34] , [35] (link). An overview of Chriesbach water chemistry is provided in Table S2. A sediment trap (0.51×0.7×2.6 m, residence time ∼20 min) was used to remove part of the dispersed particles. The flow rate in the channels was maintained at ∼1 cm/s corresponding to a volume flow of 3 L/min. Typical flow rates in the benthic zone of Chriesbach are 1–4 cm/s. Illumination was provided in 12∶12 h light/dark cycles by BioSun fluorescent tubes with a radiation similar to the sunlight spectrum (Radium Lampenwerk GmbH, Germany, ML-T8 36W/965/G13B; photon flux during light periods: 100 µE/m²s). Temperature and photosynthetically active radiation (PAR) in the channels were monitored by a HOBO Pendant Temperature/Light Data Loggers (UA-002-64). Oxygen saturation was monitored with a Presens Microx TX3 system and an NTH-PSt1-L2.5-TS-NS40/0.8-YOP-EXT1 oxygen microsensor.

Natural biofilms were colonized on glass microscope slides (38 mm × 26 mm, Thermo Fisher Scientific), which were placed vertically in Plexiglas channels in a flow-through system fed by water from the river Chriesbach (on campus, Dübendorf, Switzerland) (Navarro et al., 2007 (link); Kroll et al., 2014 (link)). An overview of Chriesbach water chemistry is provided in Supplementary Table S1. A sediment trap (0.51 m × 0.7 m × 2.6 m, residence time about 20 min) was used to remove part of the dispersed particles. The flow rate in the channels was maintained at about 1 cm/s corresponding to a volume of 3 L/min. Illumination was provided in 12:12 h light/dark cycles by BioSun fluorescent tubes with a radiation similar to the sunlight spectrum (Radium Lampenwerk GmbH, Germany, ML-T8 36W/965/G13B). Temperature and photosynthetic active radiation (PAR) in the channels were monitored by a HOBO Pendant^®Temperature/Light Data Loggers (UA-002-64) (median water temperature: 13.4°C [11.7–16.1°C], median light intensity in the light period: 1011.8 Lux).