ARC-led research vessel returns from Ross Sea expedition

Dr Laura De Santis and Associate Professor Rob McKay aboard the JOIDES Resolution research vessel

Led by ARC’s Associate Professor Rob McKay and Dr Laura De Santis (Istituto Nazionale di Oceanografia e di Geofisica Sperimentale, Italy), the 30-strong research team aboard the JOIDES Resolution travelled to Antarctica as part of the International Ocean Discovery Program (IODP).

The research team has brought back rock cores from up to 700 metres below the sea floor collected from five different sites on the West Antarctic Ice Sheet. These cores contain substantial new knowledge of past ice sheet behaviour that are critical for predicting the effect of climate change and ocean warming of this vulnerable area of Antarctica.

“We think the modern melting of the West Antarctic Ice Sheet is due to ocean warming, but we are not sure exactly how much warming is required to cause a major loss of the West Antarctic Ice Sheet,” says Associate Professor McKay. “Because of this expedition we now have records that will document the magnitude of ocean warming during major ice sheet collapse events in the geological past. It is this direct link between large changes in ice sheet size and the associated change in the oceans directly offshore that is unique to this expedition.”

This expedition also broke two drilling records: it achieved the highest-ever recovery rate from a deep drill core, which is typically difficult due to the logistical challenges of working in the Antarctic environment, and retrieved the longest-ever piston core, giving the research team a “pristine geological record of oceanographic change over a much longer time period than expected – several million years”, Associate Professor McKay says.

This expedition is only the second ship-based deep geological drilling expedition to travel to the Ross Sea. The first expedition on the GLOMAR Challenger in 1973 showed that the Antarctic Ice Sheet is over 25 million years old, which was much older than the two million years researchers had expected. This was followed by another expedition aboard the Challenger to the Southern Ocean that provided the first ocean temperature history for the last 50 million years through pioneering studies on microfossil geochemistry.

The work completed by the JOIDES Resolution and GLOMAR Challenger teams is part of a 50 year history of expeditions beginning with the Deep Sea Drilling Project in 1968. Since then, 23 countries have taken part in over 300 expeditions, culminating in the IODP, which will run until 2023.

“There’s no way one single country could afford to do research at this scale,” says Associate Professor McKay. “Working in close proximity with a diverse group of scientists from a range of different cultures and scientific approaches, every single day for two months, means everyone emerges from these cruises a better-rounded scientist.”