The oceanographic survey will estimate the flow of water through the region, and identify any sources of cold, dense bottom water (produced when sea ice forms), which drive ocean circulation patterns. This is important because ocean circulation patterns and water temperature are linked to other biological processes. In the 1996 BROKE voyage, for example, cold water welling up from below, was associated with higher densities of phytoplankton, krill, fish and whales.
The oceanographic team will use a CTD probe (conductivity, temperature, depth) to measure changes in conductivity (salinity), temperature and oxygen levels with depth, at regular intervals along transects between Fremantle and Antarctica. Water samples will also be analysed for changes in carbon dioxide (CO2) levels to determine whether the ocean is still absorbing CO2 and at what rate, and if there is a limit to how much it can absorb.