A water sampler is often used in conjunction with a CTD. The water sampler collects 1 or more actual samples of water for analysis in the lab after recovery of the package. The water samples can be used to verify the accuracy of data measured by the instruments on the package, and/or to provide additional information that cannot be measured with an instrument in the field. Sea-Bird water samplers can be controlled (i.e., bottles closed) from deck via a Sea-Bird deck unit and software, or can be pre-programmed to close bottles at desired depths. Sea-Bird manufactures two water samplers: the SBE 32 Carousel (up to 36 bottles, 1.7 - 30 liters, available in regular, compact, and sub-compact sizes, for depths to 10,500 m) and the SBE 55 ECO (small, 3- or 6-bottle sampler for depths to 600 meters).
See the following for more details on water samplers and CTDs:
- CTDs Explained provides an introductory overview of CTDs and water samplers.
- Application Note 45 provide guidelines for configuring a water sampler for your application.