AN IN SITU PARTICLE COUNTER1

Abstract

Knowledge of the microdistribution and of the microecology of plankton is an important aspect of biological oceanography. Work in this area has been hampered by observational inadequacies. Operational considerations are discussed and a specific technique is presented which offers an improved solution for some of the problems involved in this field of study. A device is described which can measure the number and sizes of individual particles such as zooplankton organisms in situ and record their spatial distribution as it is towed along transects through the sea.

Causes of under- or overestimation of zooplankton biomass using Optical Plankton Counter (OPC): effect of size and taxa

“…In order to evaluate active and passive zooplankton flux, quantitative estimates of zooplankton biomass are of prime importance. Zooplankton biomass has been measured using various methods: that include the plankton net, coulter counter (Maddux & Kanwisher 1965), optical plankton counter (Herman 1988), video plankton recorder (Davis et al 1992), and acoustics (Backus & Barnes 1957). Within these, the optical plankton counter (OPC) has been used in numerous studies (Sprules et al 1998, Labat et al 2002, Nogueira et al 2004, Huntley et al 2006, because it can measure rapidly and with ease, and can be used for in situ measurements also (Herman et al 1993).…”

An imaging-in-flow system for automated analysis of marine microplankton

“…Early studies used the Coulter principle (Coulter 1957) to rapidly obtain marine particle size distributions both in situ (Maddux & Kanwisher 1965) and in discrete water samples (Sheldon et al 1972). These studies provided the basic knowledge of particle size spectra geographically across ocean basins and vertically with depth.…”