Each system comprises twenty 600 L polyethylene tanks (Schwer-PALOXE 1130 x 930 x 600 mm) supplied with a constant flow-through of unfiltered seawater from a water depths of 2 m (Korpoström: GRUNDFOS SP 5A-12 R 5 from around 20 m from the tank system; Husö: Isku-Jet 3RP from around 300 m from the tank system).
Experiments can be run flexibly, in full 600 L tanks or in experimental (semi-independent), for example 20 L, subunits (vinyl buckets PP Plastex®).
Constant and equal inflow of water is achieved by custom-made INFLOW units (with adjustable flow rates) or HEADER tanks (10 L buckets PP OrthexTM above the water level distribute water passively among the experimental units via 90 cm long silicon tubes – 4 mm diameter, Versilic Silicon Tubing #760320).
Natural light conditions are maintained through shading nets at ~440 µmol photon m-2 s-1 (Li-Cor model Li-1400 data logger), representative of 3 m water depth in the area during summer.
Independent mesocosm tanks
- 20 tanks à 600 litres
- 112 x 92 cm in size, 60 cm deep
- Separate in and outflow of seawater ~130 L per tank per hour (entire volume exchanged ~5 times per day)
Experimental sub-units
- 80-100 units à 20 litres
- Spread across 20 tanks (water baths)
- 20 header tanks provide separate inflow of ~19 L of seawater per sub-unit per hour (entire volume exchanged ~26 times per day)