Water Samplers

Water sampling devices range from a bucket dropped over the side of a ship to large water bottles sent thousands of meters toward the seafloor on a wire. Probably the most commonly used water sampler is known as a CTD/rosette: it is a framework designed to carry 12 to 36 sampling bottles (typically ranging from 1.2- to 30-liter capacity) and a conductivity/ temperature/ depth sensor that sends information to the laboratory so that the water bottles can be closed selectively as the instrument ascends. Alternatively a single water bottle can be equipped with a spring loaded release and lowered on a line. When the desired depth is reached a messenger weight is slid down the line and trips the release allowing the end caps to snap close on the bottle. The largest water bottles, called Gerard barrels, collect 250 liters. Particles in the water samples may be quantified with a transmissometer sent down the wire or attached to a CTD/rosette. Aboard the ship, a flow cytometer may be used to analyze particles in the form of single-celled organisms for optical properties indicative of their physiology and structure.

For information on commercially available Niskan type bottles, click here.

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