An incubator for the simulation of a fluctuating light climate in studies of planktonic primary productivity

A laboratory system for the quantification of phytoplankton photosynthesis under fluctuating light climate conditions is described. It consists of 2 t emperature-controlled incubators with a variable light supply, an algal bat ch culture in incubation bottles with appropriate stirrers and a set of oxy gen electrodes to monitor algal photosynthesis. By the rotation of special grey filters between the incubator and the light source, a regular up and d own movement in the water column is simulated in up to 7 parallel bottles. Different ratios of euphotic depth to mixing depth and different velocities can be applied. Simultaneously, 8 bottles can be incubated under constant light. The system is demonstrated in experiments with Chlamydomonas sp. Fur ther possibilities of application are proposed.