The Niskin Bottle

The Niskin bottle is used to collect water samples from below the surface. To the right are two Niskin bottles as they are kept on a rack awaiting deployment.

Pictured here is a Niskin bottle being prepared to be used.

The Niskin bottle has stoppers on both ends, which are held in place by springs. The bottle is prepared by cocking open both ends of the bottle.

The Niskin bottle is then attached to a winch line and lowered to the desired depth. At that point, a small weight, called a "messenger", is loosely attached to the line and released. When the messenger reaches the Niskin bottle, the cocking mechanism releases the two stoppers, and a sample of the water from that depth is captured in the bottle.

To obtain samples from very close to the lake bottom, a Niskin bottle is attached to the SeaBird such that when it reaches the lake bottom, the Niskin's stoppers are released by a plunger that extends just beyond the bottom of the SeaBird's support frame.

Pictured here is the contents of a Niskin bottle being emptied into a sample jar for later analysis in the lab.

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