In principle plankton organisms are filtered through a nylon mesh that retains the organisms larger than the aperture of the nylon mesh. In this way large volumes can be filtered especially from sea areas with a reduced richness in plankton organisms.
It is essential that the highly sensitive plankton organisms are handled with utmost care in order not to kill live organisms during the sampling process. In case these plankton organisms are filtered by hand, the hydrodynamic forces occurring at the filter mesh are expected not to impact on the plankton individuals. For mechanical and automatic sampling, however, the flow velocity has to be reduced down to a level which ensures the hydrodynamic forces directly at the filter mesh are kept on a low level.
From the filter mesh the plankton organisms are transferred into a plankton chamber, which allows for easy observation and counting of the individuals.
The transfer of the plankton organisms from the filter mesh to the chamber is a very crucial process, since organisms of that size are hardly visible and subsequently the filter mesh has to be rinsed very carefully to make sure all plankton organisms are transferred to the chamber for counting.