Trace-Metal-Clean Sampling System: Application to Ice-Breaking Research Vessel Araon

Abstract

Trace metals generally exist at very low concentrations (pM-nM) in seawater, and could function as nutrients, contaminants, and tracers of various oceanographic processes. However, collection of seawater samples for a trace metal analysis without contamination is difficult because they exist ubiquitously. We present a detailed trace-metal-clean seawater sampling system that has been constructed on the ice-breaking research vessel (IBR/V) Araon. This sampling system consists of commercially available components without custom fabrication to minimize costs. The system consists of a polyurethane-coated aluminum rosette frame, 12-L Teflon-coated Niskin-X samplers, nonmetallic rope, and autofiring module that enables an automatic bottle firing. Using this system, seawater samples were collected in the Ulleung Basin, East Sea (Japan Sea), and the concentrations of dissolved trace metals (Mn, Fe, Cu, Zn, Cd, and Pb) were analyzed. Comparisons of trace metal concentrations to those obtained from the normal sampling system and previous data showed that our clean seawater sampling system could be utilized without metal contamination.