On the Half Moon, our students take temperature readings both from samples drawn from the surface (usually as part of comparative temperature studies), and from the water column, which means water collected from different depths at a single location.
To measure ambient temperatures within the water column, we use a Van Dorn sampler. This hollow tube can be lowered to a desired depth in the water. A brass weight is then dropped down an attached line, producing a minor jolt when it reaches the sampler. This bump snaps the tube shut, trapping a water sample inside, which can then be retrieved for analysis.
On this voyage, the research team of Alanna, Jose, and Tyron used the Van Dorn sampler to measure salinity in a water column as a component of their presentation project.