Information
Comments
Once the weather improved we recommenced CTD's.
The CTD rosette is a large metal frame with conductivity, temperature and depth sensors mounted beneath it (along with sensors for chlorophyll, oxygen, turbidity, current etc) and 24 heavy duty plastic
10 litre cylindrical niskin bottles around the edges. The bottles have sprung caps at each end and are hooked to a trigger system that can be activated one bottle at a time from the instrument room on board the ship. When we reach a station the CTD is lowered from a door in the side of the ship to just above the sea floor. Data from the CTD instruments is transmitted up the cable to computers on board and can be seen in real time so that marine scientists can see different features in the water column, such as changing temperature, high phytoplankton levels, or low oxygen. Interesting depths are chosen and bottles are fired on the way back up to the surface, capturing the water from that depth.
The oceanographers, chemists and biologists watch the CTD go down and choose which depths (and bottles) they want to sample from, then race around labelling bottles and preparing equipment to sample from the rosette as soon as it comes back on deck. It's like a dance around the CTD with everyone taking their turn, the volatile gases (oxygen and CO2) sampled first. Time is of the essence, because when sampling is finished we're usually at the next station and ready to put it straight back into the water.
We have completed 21 so far.
Cheers
Andy and Mike
Map
A map showing Australia and Antarctica. The map shows the journey of one voyage that has occured in the season, with each route highlighted in a distinct colour.