The Undiscovered Oceans LAST Year I Found Myself on a Ship Average
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Cover story | The deep Dancing viperfish, spinning rings of plankton and seven-metre-high corals. Just about every journey into the abyss reveals more surprises, says Mark Schrope The undiscovered oceans LAST year I found myself on a ship average. A huge underwater mountain range in the Gulf of Mexico, 240 kilometres called the mid-ocean ridge stretches for ●south-east of New Orleans. I was 70,000 kilometres around the planet, while tagging along with a team from Harbor Branch vast trenches plunge down as deep as 11 Oceanographic Institution in Florida, where I kilometres. For every island that breaks the work as a writer. They were there to test a surface of the water, there are thousands of camera system called the Eye-in-the-Sea, which underwater mountains called seamounts, uses red light invisible to most denizens of the rising thousands of metres above the sea floor. deep to avoid disturbing them. Down here in the abyss it is utterly dark, When the team watched the first video extremely cold, the water is often low in back on the ship, they went absolutely bonkers, oxygen and the intense pressure renders many screaming and laughing with delight. After just proteins used by surface creatures useless. an hour on the bottom, the camera had And yet everywhere there is life. captured remarkable footage of a two-metre- Take the mud flats that cover vast stretches long squid that might be a new species. This of the deep. It’s been a long time since September, the group caught a glimpse of a scientists thought of these abyssal plains as similar squid hundreds of kilometres away, a sterile desert. The surface layer teems with suggesting that it may not be uncommon. tiny worms and crustaceans that feed off Imagine, a squid larger than a human, the organic “snow” that drifts down from and we didn’t even know it existed. the waters above. Further down, however, On an earlier test in Monterey Bay off life was not thought to be possible. California, something moved the entire – Wrong again. John Parkes of Cardiff very heavy – camera system several metres. University in the UK and others have recently The video showed only a giant cloud of silt. shown that there are active populations of Whatever was responsible remains a mystery. bacteria hundreds of metres below the sea You might think there is little left to floor, feeding on ancient sediments. There discover on Earth in the 21st century, yet the may be more life, in terms of biomass, in the deep sea remains almost entirely unknown. sediments than in the water above them. And Only a tiny fraction of the sea floor has been many of the bacteria are different to anything explored. “Monterey Bay is the best observed seen before. “In the past five years we’ve found sea floor in the world,” says Charles Paull of the a new phylum of life and a completely new Monterey Bay Aquarium Research Institute kind of metabolism,” says Parkes. (MBARI) in Moss Landing, California. “Yet we’ve Rather more spectacular are the deep-sea S only seen 1 per cent of the bottom.” Even less is corals, found everywhere from 40 to 6000 PICTURE N known about life that drifts in the mid waters – metres down in waters as cold as 2 °C. Despite DE N the largest biosphere on earth. living in the dark depths, they rival their U/MI W But in recent years the pace of exploration shallow-water tropical cousins in splendour. ORBERT ORBERT N has started to pick up. New initiatives, new These animals, some of whose colonies grow funding and new technologies are producing a up to 7 metres high, typically thrive on rocky UMO/MBARI UMO/MBARI S steady stream of findings. Almost every time walls or ridges where there are strong currents E MAT E G researchers venture into the abyss, they make to bring them food and sweep away clogging surprising discoveries. It would be hard to sediments. Although they have long come up HPA GEOR HPA N point to an equivalent period on land without in trawl nets, it has only gradually become clear looking back generations. “It’s the best place how numerous, diverse and widespread they NORBERT WU/ NORBERT N in the world to be,” says Cindy Van Dover, are. Deep-sea corals are being found a biologist at the College of William and Mary everywhere from Norway to New Zealand. EXPLORATIO N in Williamsburg in Virginia. “If you want to And while only six deep-sea species can make a discovery, go to the deep sea.” build reefs, long belts of these reefs are turning FFICE OF OCEA OF FFICE O There’s a lot of it. The ocean covers 70 per up on the continental slopes around the OAA OAA N cent of the planet and it is 4 kilometres deep on Atlantic. There may be more in other oceans. 38 | NewScientist | 12 November 2005 www.newscientist.com The deep sea is home to MBARI a bizarre array of creatures – and that’s just the ones we know about The largest reef, near the Lofoten Islands off Norway, covers 100 square kilometres, yet was Bigfin squid (probably a species of Magnapinna) discovered only in 2002 thanks to special This squid, seen on around 10 occasions as deep down echo-sounding software that detects corals. as five kilometres, has huge wing-like fins extending Little is known about deep reefs, such as just from its mantle and very long, slender tentacles. how important they are as nurseries for The unique way it holds its tentacles – sticking stiffly out from its body, then bending at right angles and commercial fish species, but what is certain trailing downwards – suggests the bigfin waits for is that like many deep-sea creatures they are prey to blunder into them. Although the body is less extremely slow-growing. Cold-water corals grow than half a metre long, the tentacles extend seven only around a millimetre a year compared, metres or more. No full-grown bigfin squid has ever with several centimetres for tropical corals. been captured, but it is now thought to be the adult That makes them vulnerable. There are records form of juvenile Magnapinna squid, which live of 500-year-old corals being snagged in fishing within a few hundred metres of the surface. nets, and several deep reefs have already been reduced to rubble by trawling. Only a few reefs have been granted protection. 15 centimetres or so high, each with a sea lily The discoveries are coming thick and fast. “If we’re going to be exploiting resources on top and surrounded by bacterial mats And there are still huge areas to explore. we need to understand how fragile they are,” stretching for hundreds of metres. No one had In the southern hemisphere, deep-sea biology says Van Dover. “It’s all so connected.” ever seen anything like it before, or has any has barely begun. Most research has involved For many biologists like Van Dover, explanation for this strange juxtaposition. relatively primitive camera sleds that take however, the most fascinating deep-sea photographs as they are towed above the ecosystems are hydrothermal vents, where sea floor. Only recently have there been superheated water rich in chemicals spews Islands under the sea expeditions equipped with remotely operated from the volcanically active mid-ocean ridge, At the black smokers themselves, the vehicles (ROVs) and submersibles. Yet if surface and cold seeps, where cool, chemical-rich geologists saw what looked to them like tube waters are any clue, the depths of the southern water oozes from the sea floor. Here, bacteria worms, previously found only on Pacific vents, oceans are more diverse than those of the feeding on methane and sulphides support suggesting the vents have a novel mix of north. A 2000 expedition to the abyssal plain large communities of animals. The discovery species. But biologists who have seen videos five kilometres deep off Angola found more of entire ecosystems that do not depend on of the vents are sceptical, saying they show species per unit area than anywhere else in the photosynthesis revolutionised our view of life. stalked anemones, not tube worms. oceans, and hundreds were new to science. Yet it now turns out that these communities Another expedition – with biologists aboard – At least many of the creatures that inhabit are not as divorced from the sunlit world as is planned for 2007. the sea floor just sit around waiting to be we thought (see page 44). At the opposite end of the planet in the discovered. In the dark waters below 1000 There have been other surprises, too. Antarctic, an expedition this February to study metres, exploration can be even more difficult. Researchers are especially keen to study the break-up of the gigantic Larson B ice shelf Nets destroy many of the delicate creatures hydrothermal vents on the Gakkel Ridge in stumbled across vast cold-seep communities found in this zone, while ROVs and the Arctic, because this isolated section of 850 metres down on the sea floor that until submersibles often scare away the faster- mid-ocean ridge might harbour communities recently lay beneath the ice shelf. Large areas moving ones, such as giant squid. “The different to those found in the Atlantic and of the sea floor are covered by white mats of bathypelagic zone is by far the largest living in the Pacific. A cruise to ice-free regions last bacteria, with occasional mounds surrounded space on Earth and it’s the one about which we summer organised by the University of Bergen by clams up to 30 centimetres wide.