Near Cape St. James (N 51 14.95; W 128 59.99): Rite of Passage

Many an oceanography student earns their chops and their sea legs manning the CTD for daily casts. The job can get pretty hairy in rough weather; hard hats and life vests are mandatory.

The Thompson’s CTD array provides continuous data it is raised and lowered through the water, covering several important physical and optical traits for seawater, including temperature, depth, salinity, and the level of photosynthetically active radiation, or PAR. PAR is important because it shows you how deep plankton can live before running out of the kind of light that they need for active growth and food production (for a plant, that’s photosynthesis).

The rosette of the CTD carries bottles which can be tripped electronically to gather water from a particular depth. Water sensors are attached to the frame underneath the bottles. For this trip we run about 2-3 casts per day during daylight hours only, although for some of the more intensive survey trips, I have seen them cranking through CTD stations every hour or two on a 24 hour cycle. The job is to nudge the instrument package away from the railings while the crane lifts it on and off the ship. Fun times, especially if the waves start picking up…

This is the primary means for me to collect seawater for experiments, so yea CTD team!