Abstract
Seawater sampling was conducted by a CTD system attached with Niskin-X sampler in the R/V Mirai. Niskin-X sampler can eliminate the contamination of toxic rubber and trace metal in the bottle as much as possible, because its closure spring is arranged outside of the bottle. Teflon-coated and acid-cleaned samplers of them were usually used for the sampling of primary production as “clean” Niskin. We tested the difference of primary production between “clean” and other “normal” Niskin sampling. Primary production estimated from “normal” Niskin sampling was decreased drastically than “clean” Niskin sampling. We tested again to evaluate the cause of such difference, and it was revealed that the using of nitrile rubber O-rings in the “normal” Niskin sampler inhibited primary production.
