"Usually any water below the surface would be sea water, but we now have evidence there is fresh water under the sea bed and we want to figure out how it got there," he said.
"We have some ideas, we think it could be as old as 20,000-120,000-years-old, so it's really ancient water."
Dr McIntyre said the expedition is part of the International Ocean Drilling Programme.
This is an international marine research collaboration exploring Earth's history and dynamics using ocean research platforms to recover data recorded in seafloor sediments and rocks and to monitor subseafloor environments.
As well as trying to prove fresh water is below the seabed, the team wants to investigate how ice ages may have changed certain seabeds over a time span of tens to hundreds of thousands of years.
This is Dr McIntyre's third offshore expedition and he added: "This is ground-breaking research to identify some key questions, so I am very much looking forward to sailing on this one."
