POISONOUS carbon dioxide was rising from the sea floor like champagne bubbles. The water was hot and acidic, and it was pitch black. A more hostile environment for life to survive would be hard to imagine. Yet, when the lights of the three-person submersible in which she was travelling were switched on, the Sydney marine biologist, Dr Adele Pile, noticed flashes of red in the gloom outside the craft.
On closer inspection, they turned out to be hardy little creatures called flame-red bristle worms that had made their home in this toxic spot, 1000 metres below the surface, at the base of an active underwater volcano.
Closer to the summit of the volcano, off the coast of Samoa, hundreds of purple and blue eels were found living in rocky crevices. "Life in the deep sea is very diverse," says Pile, of the University of Sydney, who now also makes use of remotely operated vehicles for her marine research.
Soon the chance to explore this last great frontier on Earth - the deep ocean - will be open to Australian tourists, as well as other Australian scientists.
From next year, expeditions in three submersibles - the first to operate in our waters - will be run as part of a project called Deep Australia, a collaboration between marine scientists and the Australian adventure entrepreneur Mike McDowell.
There will undoubtedly be surprises ahead, says the lead researcher, Professor Justin Marshall, of the University of Queensland. "We only have a very limited idea of what really lives down in the depths around Australia."
Some clues to the kind of treasure trove that could be found, however, emerged last week. An international team of researchers studying the deep waters around Antarctica revealed they had discovered more than 700 previously unknown creatures, including carnivorous sponges, free-swimming worms, crustaceans and molluscs.
This cold, dark region had been thought to be a featureless abyss, but the opposite was true, says the team leader, Professor Angelika Brandt, from the University of Hamburg. "The Antarctic deep sea is potentially the cradle of life of global marine species," she says.
As more is learnt about the richly diverse ecosystems hidden a long way under the surface, concerns are growing for their protection from trawling and mining and pollution.
"Over the past few months, the possibility of mineral exploitation in the deep sea has moved closer to reality with the completion of the first underwater exploration for massive sulphide deposits," two north American researchers, Jochen Halfar and Rodney Fujita, warn in an article in the current issue of the journal Science.
They say underwater hot vents have been found that contain gold, copper, zinc and silver in far higher concentrations than in land deposits. Yet mining could damage their "unique and diverse ecosystems".
Regulations to minimise the environmental impact of mining are needed now, say Halfar and Fujita, before it starts. "Large capital investments and generation of revenues by underwater mining operations are likely to make regulations after onset of commercial operations even more difficult."
A former CSIRO marine scientist, Dr Tony Koslow, has written a new book, The Silent Deep, to alert the public to the threats facing life in the deep, open sea. In the mid-1990s Koslow discovered the rich diversity of life on seamounts 1000 metres underwater south of Tasmania, where fishing fleets were trawling for orange roughy.
"Before that, seamounts were viewed as not that interesting," says Koslow, who is now at the Scripps Institution of Oceanography in California. But when he turned his underwater cameras onto the underwater mountain tops he got a shock. "It was a revelation. I thought, 'Oh my, they are potentially as diverse as shallow water reefs'."
With the help of other scientists he catalogued this new ecosystem. "Of the hundreds of species that we encountered, about a third were new to science, and apparently restricted to those local seamounts," he says.
When the cameras were lowered onto the seamounts that had been trawled, however, it was a different picture. "There was nothing, only coral rubble and bare rock," says Koslow. "Fishers in 25-metre boats can level a pristine coral reef at 1000 metres depth as readily as loggers with chainsaws and bulldozers can clear an old-growth forest."
Koslow's research led to the establishment of one of the world's first deepwater marine reserves, off the Tasmanian coast, and his endeavours are now focused at the international level. Three years ago he led a call for a global moratorium on bottom trawling on the high seas, which was signed by more than 1300 marine scientists.
Unfortunately, late last year, opposition by Iceland scuppered hopes that the United Nations General Assembly would back a moratorium, although the UN did call for countries and regional fisheries organisations to prevent destructive trawling in the high seas.
Despite his initial disappointment, Koslow is heartened by recent developments. This month the first agreement of its kind to protect up to 25 per cent of the high seas was signed by nations fishing in the South Pacific, the largest pristine deep-sea environment left on Earth. The agreement, which will have a big impact on the New Zealand trawl fishing industry and comes into effect in September, will close high sea areas where vulnerable marine ecosystems are known to exist or likely to occur.
"It is real progress," says Koslow, who is also working with Professor Craig Smith, of the University of Hawaii, on a Pew Fellowship project to try and establish a global network of marine protected areas that will be off limits to fishing and mining.
Initially, the miners had focused on the manganese nuggets that litter about 70 per cent of the sea floor and which contain small amounts of cobalt copper and nickel. But the environmental cost of scraping these nodules up from large areas has shifted their attention to the vents.
Huge sulphide deposits of commercial grade ore have been found within the exclusive economic zones of Papua New Guinea and New Zealand, say Halfar and Fujita. With metal prices skyrocketing and land-based metal-rich deposits depleted, sea-floor mining has been scheduled to begin in 2009.
If these operations are successful, there is likely to be a wave of interest in deep-sea mining of ore-rich vents, more than 250 of which have been found, they say.
In Australia, the oil and gas industry and scientists are working together in the deep ocean. Pile has established a partnership with companies to explore the waters around their drilling rigs in Bass Strait and the Northwest Shelf.
The companies have donated time to Pile and her team on their remotely operated vehicles, which are often sitting idle, allowing the team to reach otherwise inaccessible areas and carry out projects such as a recent one to see whether drilling was affecting the diet of organisms in the area.
It's a win-win situation, says Pile. The scientists get to set their own research agenda, but are able to provide insights into the environmental effect of the drilling. "The companies need the information so they can do the right thing."
Being able to direct the vehicle remotely, with a coffee in hand, however, is more comfortable than being in the submersible. On the eight-hour long volcano trips Pile says she had to avoid drinking because there were no toilet facilities.
From next year, adventure tourists with deep pockets will be able to enjoy the luxury of a 56-metre long vessel, the MV Alucia, that McDowell, of Deep Ocean Expeditions, had designed for marine research, before heading off for exploration in one of its three Deep Rover submersibles. The craft have cameras and mechanical arms to sample marine life and the scientists taking part in the Deep Australia project are looking forward to new discoveries.
Marshall, from the university's Vision Touch and Hearing Research Centre, is particularly interested in the sensory systems deep-sea creatures may have evolved to cope with their unusual environments. "Imagine floating through a world for an entire lifetime where it is absolutely black and you never come into contact with a surface and you have got to find food and a mate and not get eaten."
While deep-sea exploration could bring many commercial benefits leading, for example, to the development of new drugs or devices, it is the wonder of nature that inspires Marshall. "I apply my research, but my first point of call is to say, 'Look how beautiful this is'."
In a clear sign of the wider ramifications of climate change on some of the planet's wildlife, biologists in Britain have noted that at least 11 butterfly species made their earliest recorded appearances this year. Of the 59 resident and regular migrant species, 37 have already appeared and, besides for one species (the orange tip), have done so earlier than they would've a decade ago, according to Butterfly Conservation, a wildlife organization. 
