January 3, 2013

Researchers Discover Corals At Depths Once Thought Uninhabitable

Lee Rannals for - Your Universe Online

Scientists have discovered corals at Australia´s Great Barrier Reef at depths that were previously believed to be uninhabitable.

A team of researchers with the University of Queensland's Seaview Survey has been working on a multi-year project to map out the Great Barrier Reef, and they recently announced that they have found corals in waters nearly as dark as night. The newly discovered corals sit at 410 feet below the surface at Ribbon Reef near the Torres Strait and at the edge of the Australian continental shift.

The project´s chief scientist Ove Hoegh-Guldberg said the coral had previously only been shown to exist at depths of 230 feet, and the latest finding could bring new understanding about how reefs develop.

"What's really cool is that these corals still have photosynthetic symbionts that supposedly still harvest the light," Hoegh-Guldberg told AFP. "It's interesting to know how they can handle such low light conditions — it's very deep dusk, you can barely make out much at the bottom."

The team is also interested in understanding how the coral reproduces at such depths, since most shallow corals mate at spawning events that are triggered by the cycles of the moon. At this depth, however, it is difficult to understand how enough moonlight could reach to these depths and affect coral reproduction.

"We don't know the answer to that yet, they may be doing very different things to what shallow water corals do," Hoegh-Guldberg conjectured.

The corals have been found to weather large storms on the reef much better than those closer to the surface. Hoegh-Guldberg also says the team was looking at how ocean acidification and warming has impacted the newly discovered reefs.

The team was able to discover these deep-water water corals thanks in part to unusually calm weather conditions that allowed them to dispatch a high-tech diving robot. The researchers said that large waves and cyclones in the Great Barrier Reef typically prevent access to this area.

"No one's ever seen these places. It's pretty rare on the planet today," Hoegh-Guldberg explained.

He added that the Seaview Survey is looking into a number of specimens that were thought to be new species records for Australia, many of which may even be “completely new to science.”

"It's just showing that we do have rich communities that can reach into the deep water," he told AFP. "We are yet to discover many corners of the Earth."