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Video explainer on how CTD rosette works


[Surging water can be heard and a CTD instrument appears moving to the surface of the water]

[Music plays and the image changes to show the CTD instrument being brought onto the deck of a boat, and text appears: The CTD instrument is the workhorse of oceanography]

[Image changes to show a close view of a male crew member guiding the CTD instrument on to the boat deck, and text appears: CTD stands for Conductivity, Temperature and Depth]

[Image changes to show a close view of the CTD instrument, and text appears: This one comes from a depth of nearly 4000m, collecting water along the way]

[Image changes to show a male operating a machine above the CTD instrument, and text appears: Once safely inside the ship, all 36 CTD bottles are sampled]

[Images move through in fast motion of close and then bird’s eye views of workers removing the sample water from the CTD instrument, and text appears: Two teams work around the clock on 12-hour shifts to gather the samples as CTDs go up and down]

[Image changes to show a close view of workers removing samples from the CTD instrument, and text appears: This one is number 64, nearly halfway to a planned total of 130]

[Image changes to show three workers in high-vis waterproof jackets, and text appears: This is a ‘full depth’ CTD]

[Image changes to show a close view of a female talking to the camera while her colleagues listen]

Dr Helen Phillips: Yes two, four, zero. It means we go all the way to the bottom of the ocean.

[Image changes to show a close view of Helen writing on her clipboard, and text appears: Helen’s clipboard is at the hub of this operation]

Two, five, seven. 

[Image changes to show Helen talking to the camera, and text appears: Dr Helen Phillips, Physical oceanographer, AAPP/UTAS]

Definitely. Some people refer to this position as the police, policeman, 0.9.

[Image shows Helen looking up and listening]

Male: Global data police, or just the police.

Helen Phillips: Yes, just making sure everyone goes where they’re supposed to go and uses the, gives you the sample bottle number to record, to make sure that we can keep track of which bottles were taken from which depth in the skim.

[Image shows Helen looking down at her clipboard and talking, and then the camera zooms in on her clipboard]

Two, four, two on number five.

[Image changes to show a male gently rotating a sample of water in a pot]

Five. Up here 31.

[Image changes to show sample conical flasks being put into a tray inside a box, and then the image changes to show Helen talking to the camera]

First of all measure dissolved oxygen. That comes first because we don’t want to let any of the air contaminate the sample. And then nutrients comes next. That’s the next most sensitive measurement. And then we take salinity. And we have some additional biological samples at different stations. But the oxygen, salinity and nutrients are the core samples for calibrating the electronics on the CTD.

[Images move through to show Helen taking notes while the workers work with the samples, and text appears: Working at sea is key training for future oceanographers]

Thirty-three. A14. 

[Image shows a female worker moving past Helen and talking while Helen takes notes]

Female worker: Two, six, five.

Dr Helen Phillips: Two, six, five.

[Image changes to show Helen talking to the camera]

It’s critically important because there are not many oceanographers in the world and of those oceanographers a smaller percentage would actually be seagoing oceanographers and we just don’t really get enough voyages to get out here to be able to train many people, and so yeah we grab these opportunities when we can.

[Image changes to show a close view of a worker working with a sample, and then the image changes to show Helen talking to the camera]

One thing that you don’t really grasp when you just look at the CTD is how cold the water is. The coldest in this bottle is 0.9 degrees, that’s come up from the bottom of the ocean. So, that’s really Antarctic bottom water that’s made its way north here. And to be holding your hand in 0.9 degree water is doing a careful sampling procedure. It’s pretty impressive. So, I’m very proud of my team. Awesome job.

[Image shows Helen smiling at the camera, and then the camera pans around the room to show the team working on the CTD instrument]

Male worker: Yay team.

Dr Helen Phillips: RP29.

[Image changes to show a worker watching the CTD instrument being deployed into the ocean from the boat, and text appears: And then down for yet another deep dive into the Southern Ocean]

[Image shows the CTD instrument plunging below the ocean’s surface]


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