Inducing fluid turbulence in laboratory studies
Waters enriched with mineral and organic nutrients are considered to promote proliferation of plant life that potentially reduces dissolved oxygen content and possibly causes extinction of other organisms. The so-called eutrophication is ubiquitous in European coastal areas and greatly affects industrial activities such as tourism and fisheries as well as the balance of the corresponding ecosystems. Due to the lack of detailed knowledge of key variables such as small-scale turbulence on the interaction between plankton and nutrient dynamics, eutrophication consequences are difficult to predict. With the focus on this, the NTAP project developed a system to generate turbulence in a fluid inside laboratory containers with the aid of vertically oscillating grids. Autonomous gear head motors of different nominal rotation frequency and velocity simultaneously generate a set of various turbulence levels even in multiple containers. In addition, an adjustable eccentric arm that transfers the motor's rotational motion into the vertically translational motion offers modification of grid stroke. Made of materials compatible to living organisms and compliant to food industry standards, this is a valuable species-specific tool for studying turbulence influence on plankton. Unlike most conventionally systems used, this innovation offers simultaneous testing under different turbulence levels. Moreover, the system is scalable in terms of employed motor units and volume of containers. Another important project result is a searchable database summarising the effects of different hydrodynamic regimes upon organisms, communities and biological processes. Included information involves many aspects such as temperature, salinity, organism size, nutrient and/or prey particle concentration and size. Collaboration is sought for data update as it is anticipated that this database will become a reference repository of turbulence effects on plankton.
