New ocean sediment cores are expected to contain ultra tough microbes that can survive without organic matter or sunlight, researchers say.
The US research vessel JOIDES Resolution as part of the Integrated Ocean Drilling Program docked in Auckland on Monday, carrying a payload of sediment cores containing microbes which are expected to shed light on how life might exist on Mars, or Jupiter's moon Europa and other planets.
"It's a brand new ecosystem that's never been studied before," says team member Professor Steven D'Hondt from theUniversity of Rhode Island in the United States.
D'Hondt and fellow team member Dr John Moreau from the University of Melbourne say the microbes may even run on hydrogen generated by nuclear power (from natural radioactivity), a radically different strategy to the photosynthesis on which most terrestrial food chains are based.
Researchers spent eight weeks in the South Pacific Gyre, a vast area bounded by New Zealand, New Caledonia, and Chile.
A drill mounted on the ship was sent 5.5 kilometres down to the sea floor, and then drilled 130 metres into the thick clay sediments, where a menagerie of strange microbial life is expected to live.
The pressure is extreme, there is no oxygen or light, and the temperature "is about the same as the inside of your fridge", say the researchers, making it likely to contain lifeforms radically different from those at the surface.
Now the researchers must sift through the cargo-hold full of sediment samples, analysing the collective DNA to get an idea of how many species are present.
"If we found even a 10% variation in DNA, that's a whopping amount: it would be like discovering mammals", Moreau says.
The researchers say the ocean floor microbes may be similar to those found previously in deep South African gold mines. These 'extremeophiles' use sulphate as an oxidant to split water into hydrogen, which they use as a food source.
Moreau says they also expect to find 'rock-eating bacteria' in igneous rock cores that were collected.
"What we're really interested in is understanding the ability of life to cling on under difficult circumstances, whether that's under the ocean, on another planet, or at the beginning of life on Earth," they say.
Next year, the JOIDES Resolution is scheduled to collect similar cores from tectonic spreading zones of Pacific oceanic ridges.