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- Nansen bottles are 'water sampling bottles" used by oceanographers to obtain
subsurface samples of seawater to determine the properties of sea-water. These
bottles are generally metal or plastic tubes with either plug valves at each
end. The bottle is lowered by wire with its valves open at both ends to the
desired depth. It is then closed in situ by allowing a weight (called a
messenger) to slide down the wire and strike the reversing mechanism. This
causes the bottle to turn upside down, closing the valves and reversing the
reversing thermometers, which are mounted on the bottle in a special
thermometer case. If, as is usually the case, a series of bottles are lowered,
then the reversal of each bottle releases another messenger to actuate the
bottle beneath it.
Generally a number of bottles (12 to 24) are attached at predetermined
intervals in series along the wire (a 'bottle cast') and closed in succession.
When the bottles have been brought back to the deck the water samples are drawn
through a tap, following a routine designed to obtain a pure sample. In some
designs, the bottle when tripped is released at its upper end and rotates
through 180 degrees about a hinge at its lower end where it is clamped to the
wire. This is for the purpose of operating the 'reversing thermometers' and
leads to the bottles being referred to as 'reversing bottles'. In other
designs, the bottle remains stationary while a frame carrying the reversing
thermometers rotates. A capacity of 1.25 liters is common for these bottles
but for special purposes, such as carbon-14 analysis, larger bottles are used -
up to several hundred liters capacity.
Another arrangement of water bottles is in the form of a so- called 'rosette
sampler'. In this, 12 to 20 water bottles are mounted in a single frame which
is attached to the end of the oceanographic wire. This has an electrical
conductor incorporated; the bottles can be closed when desired on electrical
command from the deck. This rosette arrangement is generally used in
conjunction with a CTD sensor head with deck read-out so that water samples can
be obtained to check the CTD or to obtain confirmation of interesting features
in the water profile.
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Taken from:
Pickard, G.L, Descriptive Physical Oceanography, 3rd edition, Pergamon Press,
Oxford, 1979. ISBN 0-08-023824-6
Smith, F.G.W, (Editor), CRC Handbook of Marine Science, Volume I, CRC Press,
Cleveland, 1974. ISBN 0-87819-388-X (Complete Set)
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