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A team of 18 scientists from around the world last year completed a massive intensive exploration of the volcanic ocean floor northeast of
Researchers from New Zealand’s GNS Science, and the National Institute of Water & Atmospheric Research (NIWA); and America’s National Oceanic and Atmospheric Administration (NOAA), the University of Hawaii, the University of Washington, Oregon State University, the University of Mississippi, and the Kiel University of Germany, used two three-person submersible subs, Pisces IV and V, and its mothership, ‘RV Kaimikai-O-Kanaloa’, to make 22 eight-hour dives on 10 active volcanoes. Reaching depths of nearly 1900m, they sampled the geology, biology and chemistry of the unexplored marine terrain and in the process saw sights never seen by humans before.
The Kermadec arc is made up some 55 large volcanoes, approximately 38 of them hydrothermally active, and is the result of the Pacific Plate diving beneath the Australian Plate. GNS geologist, Dr Cornel de Ronde, says there are a number of smaller volcanoes but as yet they haven’t surveyed these. “We are mostly dealing with volcanoes that range in size from bigger than Mt Ruapehu (2797m or 9175ft) to say about the size of Mt Edgecumbe (821m or 2692ft), smaller than that and we don’t bother.”
Many of the volcanoes which the Ring of Fire expedition dived on were only discovered last year during the NZAPLUME III expedition on the NIWA deepwater research ship ‘ RV Tangaroa’ to map the area.
“On our last voyage we found volcanoes we didn’t even know existed. Some of them are huge. Some of them have calderas in them like White Island, others have regular cones similar to Mt Tongariro. One of them, Monowai, has a caldera [very large crater] that is bigger than
“As the hot water, or hydrothermal fluid, passes through the subseafloor it will dissolve the host rock, which is full of minerals. When the hydrothermal fluid is expelled on the seafloor, it mixes with the cold seawater and the minerals that were previously dissolved in the hot water start depositing out to form mineral-laden chimneys, some as tall as seven metres high. Plumes of hot water and minerals pour out the tops of these chimneys which literally look like black smoke which, of course, is why we call them ‘black smokers’.”
The minerals dissolved in the hydrothermal fluid is thus either deposited within these ‘black smoker’ chimneys, or spreads further afield as plumes transported by currents, depositing on the seafloor various metals including, iron, zinc, copper, manganese, lead, gold and silver. The plumes are also rich in hydrogen sulphide, carbon dioxide, methane and other gases. In late 2004, Dr de Ronde managed to return with a large brittle black smoker chimney in the mechanical arms of the Japanese research submersible Shinkai 6500. The chimney was dissected and half is now on display at GNS’s new buildings in Avalon, Lower Hutt, and the other half is with
“This is consistent with what we already know. That is, that many of the world’s commercial mines for these resources were originally formed on the seafloor, later to be uplifted by tectonic forces so they can be mined on land today.”
Although it is the potential of future mineral resources which attracted a large amount of Government funding for the project, Dr de Ronde and the other scientists found something that may prove to be far more significant an abundance of uncharted life living on and around the volcanic vents. Dr de Ronde explains that most of the seafloor is like a dessert, but as the subs came upon a submerged hot spring they witnessed an explosion of life and colour.
“Most life as you and I know it derives its energy from photosynthesis, it needs sunlight. But the life we find around the seafloor hydrothermal vents doesn’t, they are what is known as ‘chemoautotrophes’ and they derive their energy from chemical reactions, particularly reactions involving sulphur as so much of that is present in these systems of the Kermadec arc. So the fluids coming out of these vents has a chemical composition that would kill you and I if we were to ingest it, the water itself can be many times hotter than boiling at the surface, there’s very little oxygen, no sunlight, and the pressure of the overlying water would easily crush a tin can, yet these animals and microorganisms live happily in these circumstances. A lot of people are therefore wondering if this is where life began? Some of the vents are more than two kilometres below the sea surface so they would never bothered by any meteorite bombardments that might have happened in the past. Around these vents there is a whole food chain ranging from microbes, and they sort of look like that stringy Chinese ‘Bird’s nest’ soup, through to mussels, clams and tube worms only found around these vents, to crabs and shrimps, and finally bigger animals like fish .”
The scientists have called the microbes extremophiles (life in the extreme), and they believe it is a life form that could possibly survive in the outer planets. Dr de Ronde says other expeditions are able to return with some of the extremophiles using an artificial environment called a ‘bioreactor’. The bioreactor contains samples at the temperature and pressure which they are sampled at, this is important as the microbes simply die in our surface environment. “It’s not easy. Can you imagine trying to do any sort of delicate operation on the seafloor with a couple of robotic arms? Even collecting larger samples with one of these things (subs) it is not as easy as people might think it is. Before scientists at the
“We don’t know a lot about these extremophiles at present, but just judging from where they live they may well be host to enzymes that could be important in the clean up of mine dumps, or other waste materials I mean some of these microbes are munching on metals and sulphur. Imagine if we could use them to deal with toxic waste and turn those wastes into some sort of environmentally friendly, to us at least, material.”
There could also be pharmaceutical applications in the treatment cancer tumours which exist in low oxygen environments. But at present these uses are speculation. “There is still a long way to go with this research we’ve got to keep in mind we didn’t even know these volcanoes existed five years ago.”
The expedition has produced a massive amount of data and dozens of samples of marine species and minerals have been brought back to labs in
Site last updated: 1 February, 2016.