Repeat survey of the International Indian Ocean Expedition line (IIOE-2)

A coupled bio-physical, ecosystem-scale, examination of the International Indian Ocean Expedition line.
Voyage No


14 May, 2019


14 Jun, 2019




Chief Scientist

Prof Lynnath Beckley


Murdoch University

Voyage summary

Research voyage to the Indian Ocean to conduct an extensive deep ocean survey in support of the 2nd International Indian Ocean Expedition (IIOE-2).

Sixty years ago, researchers aboard vessels from 14 countries combined their efforts to explore the largest unknown area on Earth, the deep waters and seabed of the Indian Ocean. This world-first expedition generated a wealth of information and provided a baseline that formed the foundation of our scientific understanding about the Indian Ocean basin.

This voyage is a repeat of the 110°E line survey from 1963, which was completed by HMAS Diamantina visiting stations on voyages undertaken every six weeks for a year. RV Investigator will visit 20 stations along a 3000 km transect off the coast of Western Australia during this one month voyage. This will be an integrated whole-of-ocean ecosystem study that includes physical processes, biogeochemistry, nitrogen sources, microbes, primary production, zooplankton, mesopelagic fishes, food webs and whales. The voyage is a major part of Australia's contribution to the UNESCO-led IIOE-2 mission and will provide data to examine the effects of climate change on the waters of the Indian Ocean.

The voyage includes only the primary research project but involves significant international collaboration.

The science team on this voyage includes 40 participants from 18 institutions - including international participation - as well as scientists and postgraduate students from seven Australian universities.

Voyage outcomes

This voyage collected important data to better understand the response of the south-east Indian Ocean off Western Australia to climate change by comparing it against historical data collected in the 1960s. Researchers mapped the physical and chemical attributes of the water column to the seafloor (over 5000 m depth) as well as the horizontal and vertical distribution of microbes, phytoplankton, zooplankton and meso-pelagic fishes in the south-east Indian Ocean.

Importantly, modern techniques allowed, for the first time, the investigation of aspects of the ocean environment such as distribution of microbes, biogeochemistry, pelagic food webs and bio-optics related to satellite remote sensing of the south-east Indian Ocean. The bio-optics measurements undertaken provide the first ground-truthing of satellite remote sensing of ocean colour in the south-east Indian Ocean.

The research delivers the first scientific understanding of biogeochemical, microbial and ecological processes in the region, which includes newly proclaimed Commonwealth Marine Parks such as the Abrolhos Marine Park . It will also increase our understanding of oceanic food webs important for supporting stocks such as tuna, western rock lobster and potential future resources including lantern fishes.

This voyage provided Australia’s primary contribution to the second International Indian Ocean Expedition, a global scientific endeavour involving scientists from about 30 countries. It also provided an important opportunity to train post-graduate students and to maintain Australia’s reputation at the forefront of international oceanographic research.

Voyage blog: Dropping a line in the Indian Ocean

Led by Chief Scientist Professor Lynnath Beckley from Murdoch University, a team of 40 marine scientists, students and technicians from 18 institutions have just departed Fremantle to take part in the 2nd International Indian Ocean Expedition (IIOE-2). Those on board will spend 32 busy days at sea, sampling across 3,000 km of the deep ocean along the 110°E longitudinal line, approximately 500-600 km offshore from the coast of Western Australia.
Read more on CSIROscope
A CTD being lowered into the ocean at sunset