The use of the Coulter Counter for the Determination of Marine Primary Productivity

Abstract

Descriptions are given of investigations into the determination of phytoplankton production by the use of the Coulter Counter (a) on its own, (b) with the addition of a pulse height analyser and, (c) with the addition of a pulse amplitude/digital converter. Method (a) was considered unsuitable because it occupied a great deal of experimental time, thus reducing the number of replicates. Method (b) was considered suitable for size distribution analysis, but the long period of time required to convert the screen presentation into total volumes precluded its suitability for production work. Method (c) proved to be the best system, since many replicates could be taken in a short time, and the conversion of megacycle counts to total volumes could be speedily calculated. The ability of this system to detect minute changes in the total particle volume content of a seawater sample has enabled estimations of standing stock, detritus, and reproductive rate to be made on samples of raw seawater from around the Faroe Islands.