AN APPARATUS FOR AUTOMATIC COUNTING AND CONTROLLING DENSITY OF PELAGIC FOOD PARTICLES IN CULTURES OF MARINE ORGANISMS

A particle control system is described for automatic collection of sam ples, and determination and control of the density of particles in mar ine suspensions. Densities are determined electronically, allowing col ourless microorganisms to be detected. Computer operated magnetic valv es allow multiple cultures to be sampled, measured and fed, using comp ressed air and a vacuum pump. Conditions and variables, determined in the software, enable flexible adjustment to specific culture condition s. The system was applied in the cultivation of the copepod Acartia cl ausi Giesbrecht, using a 95 mum orifice with a particle size range of 8 to 32 mum. Some results are given of monitoring and controlling the density of heterotrophic flagellates as food in the copepod cultures a t different conditions of temperature and autotrophic food.