The German RV Sonne is one of the world’s largest deep ocean research vessels. She was built in 2014 with a length of 118 m, breadth of 23 m and gross tonnage of 8554. She sails the world in search of cutting-edge science and we have just completed an expedition along the Great Barrier Reef margin.
Sailing from Auckland on 17 April, we transited across the Tasman Sea towards south-east Queensland and spent the first few days on the Fraser shelf, exploring lowstand coastlines, now drowned under higher sea levels.
Tracking northwards along the GBR margin, we explored the shelf-edge opposite of the Capricorn-Bunker Group using a new high-definition camera to film the beautiful mesophotic corals.
Heading across the Capricorn Channel and around the Swain Reefs, we discovered a massive underwater landslide, then a transit offshore into the deeper Coral Sea. The weather was warm and absolutely flat - perfect for mapping and deploying sampling gear.
Many sediment cores were taken to obtain paleo-oceanographic records of past climate change in this part of the South-west Pacific. A large multibeam survey off the Ribbon Reefs found numerous debris blocks from past undersea landslides settling into the Queensland Trough.
The track northwards to Cape York was astounding with many new submarine canyons revealed. Around the far northern Detached Reefs, evidence of Australia’s ancient crust was exposed, providing a platform for the growth of these strange reefs.
We completed the expedition with a transit through the shoal-strewn Torres Strait, then across the Arafura and Timor seas to Darwin, arriving on 9 May.
Many thanks are to Dr Mahyar Mohtadi, Chief Scientist, and the many other researchers from Germany, Canada, Australia, Japan, USA and The Netherlands; and also to the Captain and crew of the Sonne, for making SO256 such a great expedition and a career highlight.