Colourful Photos Reveal the Secrets of Australia’s Twilight Zone Coral Gardens

Colourful Photos Reveal the Secrets of Australia’s Twilight Zone Coral Gardens
A soft coral of the Gorgonia fan variety found in the deep-sea coral reefs of the Ashmore Reef Marine Park. (Photo: Schmidt Ocean Institute)

In the depths of the ocean off the northwest Australian coast lie vast, mysterious ecosystems. Until recently, they were completely undocumented by scientists. A team of researchers changed that in mid-April, though, after they boarded an oceanic research vessel known as the R/V Falkor. Equipped with advanced robotic technologies, the boat and its crew set out on an 18-day expedition to explore the uncharted depths. The team returned last week with loads of data to analyse and a trove of photos of these previously unforeseen wonders. Here’s some of what they found.

Short Nosed Sea Snake

A vacant shell and, to its right, a very special sea snake. (Photo: Schmidt Ocean Institute) A vacant shell and, to its right, a very special sea snake. (Photo: Schmidt Ocean Institute)

On their journey, the scientists conducted the first comprehensive study of northwest Australia’s deep coral reefs, mapping the entirety of Ashmore Reef Marine Park’s twilight zone. They also scooped up samples of sediment, wildlife, and flora, which researchers will use to gain a better understanding of the ecosystem. The team also used a robotic camera to shoot incredible high-resolution images of the habitats and animals that call the seafloor home.

At one point, the robot caught sight of the beautiful, cup-like shell on the left-hand side of this picture — a stunning thing to behold, for sure. But while the robotic camera was focused on the shell, the researchers noticed something else far more interesting to its right: a short-nosed sea snake.

But Wow, the Short-Nosed Sea Snake

The scientists thought this species was locally extinct. (Photo: Schmidt Ocean Institute) The scientists thought this species was locally extinct. (Photo: Schmidt Ocean Institute)

While checking out the area, the scientists viewed a host of unfamiliar species. But they were especially excited to come upon this short-nosed sea snake, which they saw 20 feet (67 meters) beneath the ocean’s surface.

These critically endangered, venomous creatures were previously thought to be locally extinct. The snakes were once abundant in the area, but hadn’t been seen in Ashmore Reef in 23 years.

Pygmy Seahorse

A pygmy seahorse hanging out on a coral. (Photo: Schmidt Ocean Institute, Getty Images) A pygmy seahorse hanging out on a coral. (Photo: Schmidt Ocean Institute, Getty Images)

The deep sea coral ecosystems the scientists explored are mesophotic — Latin for “middle light” — zone. More commonly referred to as the twilight zone, it’s a part of the water column that sits between the bright, shallow, coastal waters lit by the sun and the deepest, darkest depths of the ocean floor. Specifically, the scientists sent the robot to hang out between 164 to 492 feet (50 and 150 meters) underwater.

These particular coral ecosystems are full of delicate kinds of life, like this adorable pygmy seahorse. Look closely or you might miss it!

Benthic Ctenophore

A Benthic ctenophore (Photo: Schmidt Ocean Institute) A Benthic ctenophore (Photo: Schmidt Ocean Institute)

Another weird guy the scientists documented was this benthic ctenophore. Also known as comb jellies, these strange animals swim by moving their large, pulsing cilia that are arranged in vertical rows along their bodies. Like I said, weird.

Hard Coral

A hard coral captured by the robot camera. (Photo: Schmidt Ocean Institute) A hard coral captured by the robot camera. (Photo: Schmidt Ocean Institute)

Another striking image the scientists captured on their trip shows a colourful coral. Doesn’t the picture resemble a tripped-out, deep-sea version of Van Gogh’s “Starry Night?” It definitely looks like a work of art, and well …

Artist Ellie Hannon

Ellie Hannon on the research vessel with the paintings she made onboard (Photo: Schmidt Ocean Institute) Ellie Hannon on the research vessel with the paintings she made onboard (Photo: Schmidt Ocean Institute)

On the research vessel, the scientists were joined by the Australian artist Ellie Hannon, who captured the fascinating Ashmore Reef in the paintings she made while on board.

“I think art has a really important role in advocating for the environment in a way that excites people,” she said in a video about the project.

With her oil and acrylic paints, Hannon created “collages” of the twilight coral reefs rather than attempt to perfectly represent exactly what the team observed with the help of their robotic explorer.

“I wasn’t trying to represent what just one image from the camera looked like,” she said. “I was taking different coral specimens in this big mess of artwork and putting in lots of colour. That was really nice.”

Influencing Future Research

Another sea snake. (Photo: Schmidt Ocean Institute) Another sea snake. (Photo: Schmidt Ocean Institute)

Incredibly, though many coral ecosystems around the Australian continent are suffering due to the consequences of the climate crisis like ocean acidification and warming water temperatures, these mesophotic regions seem to be doing pretty well.

“Our observations of the reefs showed the mesophotic zone at Ashmore to be diverse, vibrant, and healthy,” said Karen Miller, a principal research scientist at the Australian Institute of Marine Science and chief scientist of the expedition. “We found no evidence of coral damage.”

That may be a sign that mesophotic coral ecosystems are particularly resilient to changing temperatures as well as other human pressures. But it’s also likely a sign that conservation efforts at Ashmore Reef Marine Park are going well.

These new findings, which the scientists compiled into an impact report, could help the scientific community learn more about these mysterious mesophotic coral ecosystems. The researchers hope the footage and samples they captured will eventually provide important insights into how to protect similar underwater ecosystems. Given what’s happening in other parts of the ocean, we certainly need them.