A Voyage to Inner Space
| Author |
Dave Hansford |
Add to Cart |
| Date Written |
2003-08-04 |
| Date Added |
2007-05-16 |
| Publication |
Forest & Bird |
| Categories |
Deep Sea Exploration |
Last May and June, scientists aboard the research vessel Tangaroa got their first tantalising
glimpse of life on the seamounts and abyssal plain to New Zealand’s north. The deep gave up
some secrets, but kept many more. “We came away knowing how little we know,” says one of the
voyagers.
It’s a vision from a watery hell. Little more than a mouth full of murderous fangs and a way of
aiming it, but Andrew Stewart cradles it gently, teasing out the black gelatinous features with a
practised eye for detail.
He’s excited. He thinks he could be on to a new species of deep-sea angler fish here, but the trouble
is, his lab is chock full of new species and he only has one lifetime to try and identify them
all.
All about, stainless benchtops groan under ranks of specimen jars. Peering back through the alcohol
are some of evolution’s most fantastic expressions. Even without the crazy-mirror distortion
of the glass these are bizarre animals, confirmed by the pejorative names on the labels floating
inside; spookfishes, snaggletooths, gulpers, slickheads, rattails.
This - plus a freezer full of bigger corpses - is some of the bounty reaped by the National Institute
of Water and Atmospheric Research (NIWA) vessel Tangaroa as it towed nets and dredges
about the deep in New Zealand’s northern waters earlier this year.
Supported by Australia’s National Oceans Office and the New Zealand Ministry of Fisheries, the
NORFANZ expedition took a first, albeit sketchy, look under the waters of a triangle between
Lord Howe and Norfolk Islands and the northwestern tip of New Zealand.
They began with the Norfolk Ridge, a spine of submarine scarps and volcanoes stretching between
Cape Reinga and New Caledonia.
While the scientists aboard had never been here, they’d seen the results of earlier French projects
to the north which had discovered a wealth of oddities, some of which were relics presumed to
have gone extinct tens of millions of years ago.
Stewart, the fishes collections manager at Te Papa, had come looking for answers. “If you look at
charts of the region, you see a series of seamounts running down the Norfolk Ridge.
“We know that during Gondwanan times, the ridge was at one point a coastline, which poses all
kinds of questions. For instance, do ancient species still follow a possible migration route along
the ridge? Were the seamounts acting as oases? What were the effects of various currents and
boundaries that cross at right angles to this feature, that perhaps acted as barriers to these migration
movements?”
But four weeks at sea wasn’t enough to solve all the mysteries. “It was very tantalising,” he says.
“We sampled down to 2000 metres, which sounds impressive until you realise that the average
depth of the world’s oceans is about 4000 metres. That sort of depth around New Zealand has only been sampled a handful of times.
“Because of time constraints, we only grabbed a snapshot. It’s like taking a spaceship to a far
planet and only having the time to make one pass, with all your cameras and sensors firing, then
having to return to earth.”
For all that, the haul was impressive. Tangaroa’s nets and dredges disgorged around 500 species
of fish, some that were readily identifiable (many more that weren’t), and some 1300 species of
invertebrates.
Part of the booty was eight drums of “gribble”, or fine, shelly seabed sediment, which Te Papa
malacologist Bruce Marshall began sifting for tiny molluscs.
During the first 10 hours of work, says Stewart, a new mollusc emerged about every two minutes,
eventually topping out at over 600.
On his first assessment, he says he has about 34 new fish records for New Zealand, roughly half
of which are also likely to be new to the planet.
But what is all this good for? Why should we know - or even care - about what burrows through
the mud and darkness two kilometres under the sea?
Clearly, Stewart has his own reasons, but he gives the official line; “New Zealand is a signatory
to the Rio Convention on Biodiversity… which means that we’re obliged to care about the
biodiversity within our region. And with that obligation comes the duty to answer the questions;
‘What is the fauna and flora of New Zealand. What is unique here? How do we care for it?’”
Often, he says, the little things get overlooked in the stampede to examine the big things. “But the little things are the key to the survival of the big things.”
Especially in the endless cold night that is life at 2000 metres. “In the midwater,” says Stewart,
“animals are born, live and die without ever seeing the sea floor or the sun, floating in a kind of
inner space.”
“Although it’s the world’s largest habitat, it’s not the most densely populated (Tangaroa trawled
the midwater for hours to capture a single tray of fish), so fishes such as angler fishes have huge
mouths and elastic stomachs, so they can accommodate any type of prey that comes their way.”
Useful when your meals could be months apart.
In this frigid netherworld, finding sustenance - or a mate – takes on a whole new level of difficulty.
It’s an arms race down here. Devices that the world’s military have spent billions of dollars
devising, these creatures have produced with little more than DNA and a few millennia.
Most of the denizens down here are black, or blood red. There is no red light at these depths (it’s
the first band of the spectrum to fail in the fading light), so a red-coloured animal is all but invisible
to predators.
But some hunters have developed eyes that can detect the faintest of silhouettes against the
barely perceptible glow from the surface.
So some of their prey possess banks of light-emitting organs along their underbellies. They can
switch them on to match the exact hue and shade of the faint surrounding light so that their narrow bodies simply blend into the background.
Other predators have learnt to “see” in infrared, a normally invisible wavelength. Their hapless
prey have no idea they’re being stalked, except for those that have responded by producing their
own “cloaking devices” which block infrared emissions.
Others have learnt to escape by startling their pursuers with brilliant flashes of bioluminescence.
It’s this sheer ingenuity that’s captured Andrew Stewart; “The incredible diversity of ways in
which these fishes successfully answer the demands of life at depth.
“It’s the wonder of it.”
It’s said we know more about the dark side of the moon than our own seabed. Stewart points out
that the space probe Magellan mapped the surface of Venus down to just metres, yet we’re familiar
with perhaps 10 per cent of the continental shelf and the abyssal plain beyond.
By his reckoning, a stranger to New Zealand science turns up, on average, every two or three
weeks.
Which is why he’s champing at the bit to go back to the deep. He would love to bring one of the
world’s few 4000 metre-capable submarines out here for a closer look. “I’d go back tomorrow.
There are other ridges to the north; the Three Kings Ridge, the Kermadec Ridge, then there’s the
Puysegur Trench, the Tasman Basin off Fiordland.
“I want to know what’s down there.”
© Dave Hansford/ORIGIN NATURAL HISTORY MEDIA