Getting busy carrying out the science Toby Tyrrell, January 11, 2013
Today we got down to business with the first‘ CTD’ station. For those of you not familiar with the term, or who don’ t remember if from one of the previous cruise blogs, CTD stands for conductivity-temperature-depth. Clearer now? No??
In practice, it is used to refer to a metal frame which is lowered down into the sea on the end of a metal wire, carrying on board a rack of water sampling bottles( see picture). These bottles are sent down with both ends open and are then‘ fired’( closed) at specific depths in order to capture water samples from those depths. The metal rack also has some measuring devices attached to it. The complement of measuring devices always includes one for measuring conductivity( from which the saltiness of sea water, its salinity, is calculated), one for measuring temperature, and one for measuring pressure( which tells us about depth). Hence CTD.
The rosette-sampler / CTD going into the water – with the tubes open. At the selected depth they will be snapped shut to collect a water sample @ Jeremy Young
The CTD was put into the water at about 6:30am and came out again maybe 30 minutes later. Once back on board, a variety of different bottles, pots and carbuoys were brought
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