Water sampling

Amy helps to deply the in situ pump as Claudia looks on.


Water sampling is an important part of any oceanographic cruise, as we compare the current state of the water column with recently settled sediment. This sediment/water relationship is crucial when reconstructing past ocean conditions from a sediment core.

Water samples are obtained from a rosette, which is made of 24 10 liter bottles and an instrument known as a CTD (which stands for conductivity, temperature, and depth). The rosette is carefully guided off of the deck using a winch and guiding lines to keep it from swinging. When the rosette reaches the desired depth, the bottles are snapped shut, trapping the water sample inside.

Back on the ship, we filter nearly all 240 liters for samples such as chlorophyll, particulate organic matter, and nutrients. We use a pressure filtration system that actually uses old soda containers (from Coca-Cola!) that we pressurize to force water quickly through a filter.

The rosette consists of 24 niskin bottles and the CTD

Kara prepares the lines to hook the rosette when it is brought back out of the water.

Enrique fills the canisters for pressure filtration.

Kara seals water samples for stable isotope analysis.

Laura prepares to filter water in the wet lab.


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