Sustained monitoring of the EAC: mass, heat and freshwater transports

Recovery and re-deployment of the East Australian Current (EAC) mooring array.
Voyage No

IN2019_V05

09 Sep, 2019

to

29 Sep, 2019

Brisbane

to

Brisbane

Chief Scientist

Dr Bernadette Sloyan

Institution

CSIRO

Voyage Summary

Research voyage from the continental slope to the abyssal waters off Brisbane to recover and re-deploy an array of six moorings in the East Australian Current (EAC). The EAC mooring array is a component of the Integrated Marine Observing System (IMOS). 

The East Australian Current (EAC), a southward flow off eastern Australia, is one of the major global western boundary currents. The EAC is the dominant mechanism for the redistribution of heat and freshwater between the ocean and atmosphere in the Australian region; it is a vital component of the eastern Australian coastal ecosystem.

The EAC mooring array monitors the mass, heat and freshwater transported by the EAC, which is central to our understanding of how climate signals are communicated through the ocean. Moorings are deployed in water depths from approximately 500 m to 5000 m.

The voyage also includes the following research project:

  • Dynamics of larval fish diversity for ocean observing off North Stradbroke Island (Prof Iain Suthers, UNSW): Plankton and larval fish will be surveyed to better understand biodiversity and factors that influence productivity in continental shelf waters.
  • Argo float deployments (Dr Peter Oke, CSIRO): Four Argo floats will be deployed during the voyage as part of the international Argo program.

The science team on this voyage includes 31 participants from four institutions. The voyage is part of a multi-year project in support of IMOS.

Voyage outcomes

During this voyage, researchers successfully recovered and deployed six moorings in the EAC between the continental slope and the abyssal plain off the coast from Brisbane. In addition, 12 CTD/LADCP stations were completed, which will support the moorings in effectively tracking variability of the EAC. Transit periods during the voyage were utilised to conduct 114 plankton tows which will be used to assess the ramifications of a changing EAC on coastal ecosystems.

The voyage has contributed to the long-term monitoring of the EAC to ensure that vital data on the redistribution of heat, freshwater and biomass is captured. Moorings will monitor changes continuously, which will contribute to high quality regional and coastal models being developed by Australian researchers.

A survey of larval fish and plankton diversity off North Stradbroke Island was also completed during the voyage and four Argo floats were deployed as part of the international Argo program.