A routine device for high resolution bottom water sampling

The BoWaSnapper was designed to be operated on any research ship's wire and allows time-efficient high-resolution sampling of bottom water. The bottommost 2 m are sampled with six vertically adjustable bottles. Prior to closure, the bottles are aligned with the bottom current by means of a vane and flushed by bottom water for several minutes. This ensures that particles dispersed upon the touch-down of the BoWaSnapper are flushed away. An electronic mechanism, activated by a bottom switch, initiates bottle closure after a delay pre-selected by the user. As illustrated by several examples, the transparent bottles (6 L volume each) allow the determination of particle concentrations as well as the analysis of solutes such as nutrients, dissolved gases, and natural radiotracers. Although the sampler is universally suitable for seafloor environments, its special domain is characterised by steep geochemical gradients such as cold vents and submarine groundwater discharge.