The Experimental Stream Facility (ESF) is a unique platform for developing ecological and ecotoxicological research.

It consists of channels or mesocosms that allow simulating multiple river conditions and thus being able to study how river organisms and processes are affected by changes in:

• temperature
• light
• hydrology: water speed, flow…
• concentrations of chemical compounds: nutrients, pharmaceuticals, pesticides…
• biota: microorganisms, macroinvertebrates…

It is a very useful tool for studying, among others, the self-purification capacity of rivers and the impacts of drought, rising temperatures or the presence of chemical pollutants in river ecosystems.

Technical description of the channels

• Possibility of having up to 24 channels in operation simultaneously.
• Methacrylate channels 2 m long by 10 cm wide with a capacity of approximately 10 L of water. Each channel pours the water into a channel collecting tank of approx. 50 L.
• The canals can be fed with dechlorinated mains water, with rainwater or with the canal’s own water collected in the collecting tank (recirculation). Channels can operate in open flow, closed (recirculation) or semi-closed (if new water only enters for short time intervals).
• Flexibility in water flow (10-100mL/s) and residence time in the channel (2-50 min).
• Home automation control of lighting, water flow, water temperature, air conditioning and addition of chemical compounds.
• Typical duration of experiments from a few weeks to 3 months.

Circular mesocosms or “doughnuts”

• The paddles generate a unidirectional flow of water that simulates river conditions.
• Especially useful when you want to carry out short experiments (a few days) and with smaller volumes of water (4L).
• Because they are made of glass, they allow studying adsorbent chemical compounds

Associated techniques

• Biomass and microbial biodiversity
• Photosynthetic efficiency
• Primary production and respiration
• Decomposition and enzymatic activities
• Invertebrate diversity and herbivory rates

Accumulated experience

Since its inception in 2012, the facility has enabled research in different areas, attracted the interest of international researchers and encouraged scientific collaborations. Some examples of the research developed at the facility:

• Freixa et al. 2017. Warmer night-time temperature promotes microbial heterotrophic activity and modifies stream sediment community. Global Change Biology. Doi: 10.1111/gcb.13664.
• Aristi et al. 2016. Nutrients versus emerging contaminants or a dynamic match between subsidy and stress effects on stream biofilms. Environmental Pollution 212: 208.
• Corcoll et al. 2015. Effects of flow intermittency and pharmaceutical exposure on the structure and metabolism of stream biofilms. Science of the Total Environment 503: 159.
• Acuña et al. 2015. Increasing extent of periods of no flow in intermittent waterways promotes heterotrophy. Freshwater Biology 60: 1810.