Water samplers for open ocean tracer release experiments

Abstract

Conventional "spot" sampling of patchy distributions of oceanic constituents can lead to sampling errors. Interpretation of results based on data of disparate temporal or spatial resolution can be difficult or impossible. Ths report discusses the design and performance of two water sampling devices which attempt to minimize these problems. The devices were created for open ocean tracer release experiments, but can be used for other experiments where inhomogeneity is anticipated. The first sampler is a mechancally-operated, variable-rate integrating water sampler which acquires a time-averaged sample. The sampler incorporates featues of both the spring-driven and the hydraulically-driven samplers described by Ledwell et al., 1991. The second sampler is a multichamber sampling system incorporating a battery powered pump and valve system made by McLane Research, Inc., of Falmouth, Massachusett. The system consists of a micro-gear pump, a 50-port valve with programmable controller, and carousels contaning fifty glass sampling syringes. It can be programmed to sample on a variety of schedules allowing the user flexibilty in the field to adapt to changing requirements. A general description, operational instructions, and performance analysis are provided for each sampler system.