Day 6 More teams to visit across the ship: Christian Halverson

By October 2nd, 2017


As we near the more northern parts of Australia, the crew is gearing up to do more of the research that will deploy equipment over the side or aft (back) of the ship. We are taking a box core sample of sediments up in the Torres Strait area and continue to take water and atmospheric samples for the Natural iron fertilisation of the oceans around Australia study. I had really hoped to see the Conductivity Temperature and Depth (CTD) unit deployed. This is a carousel with 36 Niskin bottles, large bottles that will be triggered at depth to collect water samples all the way from the bottom of the ocean to the very surface. I did get to see the unit, and even six kilometres of Kevlar rope that is used to take it down and bring it back. The Kevlar rope is neutrally buoyant, and therefore weighs a lot less than a six kilometre steel cable.

The Seagoing Instrumentation Team (SIT), with the deck crew, set the CTD unit with its bottles. It is lowered over the side, where the Geospatial Survey and Mapping team (GSM) have mapped the depth and the hydrochemists are ready and waiting for the samples as they return to the ship. Meanwhile, the Data Acquisition and Processing team (DAP) is monitoring the whole lot in real-time, feeding data to all who need it. The unit may take up to six hours to get to the bottom and return, but of course this is barely the beginning.

There is a whole area of science called metrology, not meteorology, it is the science of taking the most accurate measurements that we can. The Niskin bottles hold lots of water from a specific depth, with all of the chemicals that it may contain. The carousel also has a logging unit that probes for salt levels, temperature and pressure and is checked as the unit goes up and down. The water is now super accurately analysed for salt levels, oxygen levels, CO2, trace elements, you name it. This is given back to the DAP team and all of the probes can now be calibrated to incredible accuracy. The whole data set is looked at, reassessed and refined for its level of accuracy, based on all of the separate data sets coming in.


Finally, when all are happy with what has been recorded, the whole project is saved and given to the scientists. Yet again, it does not end there. The whole lot will be made available for everyone to use—the scientist has a certain amount of time to use the data for their own project but then it has to be made public. Finally, it is archived. Marine National Facility (MNF) and CSIRO have 35 years of oceanographic data for all across the world to use. What do you think? Science money well spent for the greater understanding and fairer use of the world’s ocean resources? Obviously, you know my answer! We need more of these vessels and we need more teams of scientists capable of doing this important work. Maybe you are the next one to work for the MNF, or to come up with the project that needs their help!