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From: Rudy Kloser, Voyage Leader, Leg 3

The last week of the voyage has gone exceedingly smoothly. After riding out the rough weather we have had smooth seas for a week. This enabled us to complete all our lost stations in the 55m 90m and 140 m stations in the Great Australian Bight (GAB) Benthic Protection Zone (BPZ). Both scientific staff and the vessel's crew have been putting in an extra effort to ensure we make up for lost time. The exciting part of the last few days has been the work by the marine geoscientists from the Australian Geological Survey Organisation (AGSO) to investigate some unique seabed features in 4500 to 5000 m of water. Previous work by an AGSO swath survey, AUSTREA1, in January of this year found several large holes 2500 m across and 500 m deep in the GAB BPZ. These features have not been found anywhere else in the world, so they needed special investigation.

To explore these features the AGSO scientists brought on board a deep water corer and rock dredge. To reach 4500 — 5000 m the special team needed to join two very long cables together that gave us a total of 6000 m of wire. When the first sediment cores came on board we all gathered around to see the results. In non scientific terms is was cold light coloured mud that looked a bit like cream muddy clay, covering a dark thick clay inside the holes. Of course the scientific version is more instructive where the soft mud was an ooze made from planktonic foraminifera and diatoms and the dense dark clay was made of different organic material and had small pyrite crystals starting to grow in it.

These samples were packed in special containers kept at 3 degrees centigrade and transported to the laboratory for further sedimentological analysis.

In total the AGSO team completed eight deep water cores and three rock dredges completing their objectives, they are very pleased with the results. Now we are packing up our scientific equipment and getting ready for docking in Fremantle near Perth, Western Australia. The crew and scientists are thinking of returning to their families and walking on dry land many of them having spent 2.5 months at sea.

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