Tasks normally performed by watchstanders & volunteers after training:

  • CTD prep – draining and rigging of CTD for deployment 20mins before station. Rosette bottles are drained, bottom lanyards unclipped; once drained, all valves are closed and rotated 90°, breathers are closed (lightly finger-tight), & spring-loaded bottles are rigged open so they can be closed at target depths.
  • CTD launching and recovery - help untie the deck lines; handle tag lines to keep the package from swinging during deployment; hook the CTD on recovery and help land the CTD safely on deck; tie the CTD back down
  • Sample Drawing – Refer to the electronic sample log screen or ask the watchleader for the bottle numbers to sample.  The number of samples and the bottle they start on can vary - shallow stations have fewer bottles; others may have extra bottles with additional samples to draw. But typically the sample bottle number should match the CTD bottle number so double-triple check when drawing samples. Certain sample types may not be drawn from all the bottles. Shallow stations samples may share an oxygen or salt case so sample bottle numbering will not always match the CTD bottle. The watchleader should tell you when the numbers are different.
    • Samples drawn are:
      • Oxygens – must be drawn first to minimize contamination, usually by the CTD operator
      • DICs - (drawn on ~16 stations only) must be drawn immediately after the oxygens
      • Salts – very sensitive to fresh water contamination (ie rain) and evaporation
      • Nutrients – very sensitive to phosphates (soap residue on hands) or cigarette smoke (ammonia contamination)
      • Chl – samples are volumetric so no bubbles are allowed in the sample bottles
      • HPLC – volumetric, filled completely; volume varies with chlorophyll concentration
      • Phyto – “Pooh” sample from ~10m; formalin preserved, no rinses; usually taken by the CTD operator
      • Prodo – Primary productivity C14 uptake experiment, done at the noon station; samples drawn by the prodo person
  • All sample containers except the 10m "phyto" (phytoplankton; also called "Pooh") samples require 3 rinses.
  • Chl filtration – ~14 chlorophyll samples are taken to the Chl van and filtered asap (usually during the Bongo net deployment)
  • HPLC filtration – usually done along with chl filtration but may take much longer to complete because of larger volumes. Do not let the filters dry out.
  • Net deployment & washdown – launch, recover and washdown Pairovet, Manta, and Bongo nets.  Refer to the Fisheries Net Handbook for information on net types.
  • Zooplankton sample “pickling” – formalin-preserve net cod-ends.  Let the Chief Scientist know if you are sensitive to formalin or any other chemical.
  • Secchi disc – deploy, determine secchi depth, recover; daytime stations only.
  • Chl sample analysis – after 24+ hours of extraction, the chlorophylls can be measured on the fluorometer during transits between stations.