Between the sunlit shallow waters of Australia's northern coastline and the darkest depths of the ocean floor lies a world between worlds — mesophotic coral ecosystems that could hold new information on reef conservation.
A team of researchers departed from Darwin harbour on Friday for a three-week expedition on board the Schmidt Ocean Institute's R/V Falkor to explore previously undocumented deep-sea coral reefs in the Ashmore Reef Marine Park.
Although Australia is famous for its shallow water coral systems, like the Great Barrier reef, mesophotic coral ecosystems — found between depths of 30 to 150 metres — are largely unexplored and unknown.
Chief scientist Karen Miller from the Australian Institute of Marine Science said mesophotic reefs were difficult to study, as specialised equipment was needed to access them.
"It's not quite light and it's not quite dark, so it's like twilight. Because it's got a very different light regime to other areas of the ocean, what we expect to see is quite a different suite of species that are specialised," she said.
"We're excited to be able to study that unknown area and to see what species are living there that we don't necessarily know even exist yet."
Dr Miller said it was the equipment on board the ship, including the remotely operated underwater vehicle SuBastian, that allowed them to push into new territories.
"It's that technology that enables us to be able to go down and study these reefs in detail," she said.
"In Australia, we've never really had very good access to these kinds of facilities before."
She said they were also going to be trialling new technology, including hyperspectral imaging.
"Basically that enables us to look beyond the visible wavelengths of light," she said.
Nerida Wilson from the Western Australian Museum will be coordinating the biodiversity collections of the trip.
She said their findings could help conserve reefs during climate change.
"We'll understand if they are providing a refuge for the shallow water animals, so we will also know to follow what happens to the animals that are currently only known in mesophotic areas.
"It's quite complex to try and figure out what happens in the future, and the more we understand now the easier our job will be then."
Dr Wilson said the advanced technology the team was able to access would now allow for deep-sea sample collection.
"So that opens up a lot of additional ways to investigate the species in those areas by doing things like looking at their DNA," she said.
The team hopes their research results could help lay foundations for effective monitoring and protection of reefs around the world.
