JR224: Chemosynthetic life in the Antarctic


 JR224



Cruise diary


Monday 19 January 2009
Location: In transit towards South Georgia Island (53º55.35S - 41º25.40W)

The team gets ready to sniff at vents and seeps

The sensors team (Cédric, Alex and David) have been busy preparing the different sensors that we will use to ‘sniff’ the chemicals in the water column that will give us clues as to whether we are close to a hydrothermal vent or a cold seep. Vents and seeps expel fluids charged with reduced chemicals and metals. (See ChEss website for further details). In the case of vents, the fluid is buoyant because it is warmer than the surrounding water, so it creates a plume with specific chemical composition and temperature that rises until it is stable and diffuses horizontally. It is this plume that we are trying to smell with the different sensors and equipment on board, which will tell us that we are close to one of our targets!

The chemistry team (Doug and Sarah) have also been busy preparing the equipment that they will use to analyse chemicals in the water. They have two gas chromatography systems (GC) to measure methane in the water, one for surface water and air collected continuously, used as background data and one to analyse methane from water collected at different depths with the CTD. The CTD is a rosette with a series of bottles that is deployed vertically in the water column and measures continuously Conductivity, Temperature and Depth, as well as being able to take water samples at different depths. High concentrations of methane in the samples will indicate that we are not far from a cold seep.

Today we had the first equipment deployment: the CTD went in the water for the first time.

Cédric, Alex and David getting the sensors ready

Doug and Sarah working in the chemistry lab

The CTD being deployed for the first time

 


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