https://cdn.earthdata.nasa.gov/conduit/upload/5182/KeywordsCommunityGuide_Baseline_v1_SIGNED_FINAL.pdf 23.8 2026-04-29T10:52:37.449Z https://gcmd.earthdata.nasa.gov/KeywordViewer/scheme/instruments/b79c7e06-cd07-442f-bf12-2019cd71c201 NISKIN BOTTLES The most commonly used water-sampling bottle at present is the Niskin bottle,with spring-loaded end-caps with rubber washers. These are plastic(polyvinylchloride) bottles with stoppers at each end. The stoppers are heldtogether by a rubber cord or spring that pulls them together from inside thebottle. The water-tight closures at both top and bottom, equipped withsubsampling spigot and air vent, can be remotely triggered at pre-determineddepths in the water column to collect seawater samples for discrete chemicaland biological measurements. To cock these bottles, lanyards are used to pullthe stoppers away from the bottle, leaving the bottle wide open for water toflow through. The bottle is tripped by activating a firing mechanism thatreleases the lanyard, allowing the stoppers to close on the bottle therebytrapping the seawater sample. Niskin bottles can capture a much larger volume of seawater than the olderNansen bottles. Reversing thermometers on Niskin bottles are mounted in aspring-loaded frame that rotates the thermometers at the same time that theNiskin bottle stoppers are closed. These are used with most rosette samplers,the most common arrangement for water bottles, where a single frame carries upto 36 water bottles. Water bottles are mounted in a single frame that isattached to the end of the oceanographic wire. This has an electricalconductor incorporated; the bottles can be closed when desired on electricalcommand from the deck.