Comparison of Holographic and Coulter Counter Measurements of Cavitation Nuclei in the Ocean

Holographic and Coulter Counter detection techniques were jointly used to measure the concentration density distribution of cavitation nuclei in the ocean. Comparison of the two techniques indicates that Coulter Counter analysis measures particulate contents up to an order of magnitude smaller than indicated by the holographic method and may also produce a distorted concentration density distribution. Several possible explanations of the observed discrepancies are proposed and discussed, including fundamental differences between the in situ holographic samples and the collected samples examined with the Coulter Counter, differences between the unknown electrical conductivity of the measured particles in the sea water samples and the non-conductive polystyrene spheres used to calibrate the Coulter Counter, the rupture of aggregate particles in the flow through the Coulter Counter orifice, the effect of electronic noise on the Coulter Counter signal, and the influence of statistical sampling error.