Scientists on a research vessel probing Australia's oceans have found a new reef as tall as a skyscraper, the longest recorded sea-creature, and new species, but warn the fragile coral ecosystems are being decimated by climate change.
Researchers working on board the research vessel the Falkor have found a new reef as tall as a skyscraper in the waters off Cape York in North Queensland.
The 'detached' reef is the first to be discovered in more than 120 years. It is about 1.5km wide, and reaches down to more than 500 metres below the surface - making it larger than the Empire State Building.
Researchers discovered the 'blade shaped' reef on 20 October during a 12-month mapping project of Australia's oceans. It's estimated to be 20 million years old at its deepest part.
Queensland is home to the Great Barrier Reef, the world's largest coral reef system, made up of more than 2900 reefs. A "detached" reef refers to one that's bedded to the ocean floor, rather than part of the main body of a wider reef system.
The newly-found coral formation sits among a cluster of seven other detached reefs that were mapped in the 1800s. However the marine ecosystem on the top of this latest find appeared to be more vibrant than the others, according to research leader Robin Beaman from James Cook University.
"It's got a thriving coral community at the pinnacle," Dr Beaman said.
"When we got to the crest of it - it's only about 300m by 50m wide - we found a lot of fish and a healthy shark population too."
Detached reefs of this nature act as isolated seamounts, (a structure that rises from the ocean floor without reaching the water's surface) according to Dr Beaman. Because there is a lot of deep water between it and the next coral community, they have the potential to evolve unique species.
The team has been exploring the reef using an underwater robot called "SuBastian", which has a remotely controlled arm, to collect samples for identification.
"As a collective over the entire [12-month] expedition, we've been finding a whole lot of new species," Dr Beaman said.
"It's going to take time for us to work through the imagery and samples we've collected before we can say if there are new species [at this reef] or not."
They made the discovery about 80km east of Cape Grenville, on Queensland's east coast.
The researchers found new reef- building evident down to about 200m, and said during the last ice age some of the reef would have been in much shallower water, or even exposed.
'World's longest recorded sea creature' among new finds
The Falkor is being funded by the Schmidt Ocean Institute - a research body founded by American philanthropist and businesswoman Wendy Schmidt, and her husband, former Google chief executive Eric Schmidt.
Several new species have already been discovered during the project, Institute spokesperson Carlie Wiener said, as well as the "world's longest recorded sea creature" - a 45-metre long siphonophore found at Ningaloo canyon, off Western Australia.
A siphonophore is a type of colonial organism; it's a string-like arrangement of many individual animals - zooids - that live connected together in a colony, and carry out different functions that allow the collective to digest food, float, reproduce and move about.
Wiener said their latest reef discovery demonstrated how valuable the project is.
"Australia has no dedicated underwater vehicle, so there are a lot of areas that haven't been looked at before. This is evidence for the importance of exploring our undersea environment, so that we can protect it."
Scientists warn the reefs face devastating survival challenges
Just weeks ago the Royal Society published research showing half the corals on the Great Barrier Reef have died since 1995, due to climate change- induced coral bleaching.
The extent of deeper reefs, like the one just discovered, is only now becoming known as technology has improved, said reef scientist Terry Hughes from James Cook University, who co-authored that study published by the Royal Society.
The highest point of the newly discovered detached reef is 40 metres below the surface, making it a mesophotic reef.
"Mesophotic reefs - reefs deeper than 30 metres, it turns out there's probably at least as much coral habitat below 30 metres as there is above it, and people are still mapping it," Hughes said.
Because of their depth and distance from shore, mesophotic reefs are less susceptible to bleaching, cyclones, fishing pressure and land-based pollution, however they are still degrading, albeit at a slower rate than their shallow-water counterparts.
Because most coral and marine species are restricted to specific zonal conditions, mesophotic reefs aren't going to help restock shallower reefs damaged by bleaching events or other impacts, he said.
"There's been some speculation that's pretty well resolved now, that the deep reefs could be reserves for the shallow ones. That turns out not to be the case," he said.
"Many corals are shallow water specialists and others are deep water specialists and only a few have a broader depth range. There are corals that you only find shallower than five metres [and] there are other corals you only find deeper than 30."
While findings like this are interesting, Hughes said that we still need to urgently get emissions down to protect shallower corals.
"We still have an opportunity to save the reef if we deal with climate change.
"1.1 degrees of warming so far has triggered five bleaching events since 1998; [but] we still have half a reef."
"What [warming] stabilises at will be critical. 1.5 to 2C is doable, but the mix of species will be different. It already is. If we go to 3 or 4C it will be a pretty sad state of affairs."