On January 11th 2008, Australia's Marine National Facility RV Southern Surveyor embarks on a three week voyage to survey deep-sea coral beds in the Tasman Sea and Southern Ocean. The composition of deep-sea corals is used to determine previous deep ocean conditions, such as temperature, salinity and the mixing of surface and deep water layers over a time scale of tens to hundreds of thousands of years. Using specialised remotely operated underwater vehicles, sampling will occur down to depths of 4000m – deeper than ever before in Australian waters. The findings will contribute to models of regional and global climate change based on deep-sea circulation patterns in the Southern Ocean as well as documenting the biodiversity of life at extreme depths.

About the voyage

The primary voyage objective is to identify areas of high quality live, sub-fossil and fossil corals off south east Tasmania (to be sampled on the follow-up US vessel cruise). Three broad areas of interest have been identified: the Southern Seamounts, the Tasman Fracture Zone, and the South Tasman Rise. This objective will be met by deploying an Autonomous Benthic Explorer (ABE), a non-tethered instrument specifically designed for survey work to depths of about 4000 m. The second objective is to document biodiversity of the deep-sea areas of the newly declared South-east Commonwealth Marine Reserve Network. High resolution video surveys and targeted benthic sampling will be conducted. A third objective of the voyage is to collect surface plankton samples for invertebrate larvae while steaming across the shelf out of and back in to Hobart.