Early one November morning in 1963, a fissure opened in the bed of the Atlantic Ocean, about 30 kilometres south of Iceland. Red-hot magma rushed up through the crack in the Earth鈥檚 crust, and icy cold ocean water poured down into it. At the surface, fishermen began to notice black smoke rising from the sea and a stench of sulphur. For months, there was a constant submarine battle between the volcano, which spat out more than a cubic kilometre of lava, and the ocean, which did its best to wash it away. Eventually the volcano won, and over three more years of intermittent eruptions, an island formed and solidified above the waves, before the eyes of an astonished world.
THE creation of Surtsey, named after a mythical Norse fire-eating giant, was a dramatic affair. Magma erupted from three different fissures about 120 metres below the ocean surface. Each time the eruptions resumed, the sea boiled and the lava solidified into tiny fragments that formed bright red fountains and sent mushroom clouds of steam and black ash high into the stratosphere. Bolts of lightning shot to the ground from the volcanic clouds. The ash rained onto the newly formed land, often inside giant hailstones. The fallout eventually created a wide black ash plain around the island鈥檚 central crater of solid volcanic rock.
It was, some said, like the world being born afresh. It was like Mars, said NASA scientists, who saw a resemblance to the surface of the Red Planet. It is doomed, said others, predicting that the island would be eroded away within a few years. All have been confounded.
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Even as early as Surtsey鈥檚 first spring, in 1964, when scientists first tentatively set foot on the new island, they discovered it was no longer barren. Those first visitors found a fly on the shore, and some seeds, apparently dropped by passing birds. The following spring, they were greeted on the high-tide line by the green shoots and pretty white flower of a sea rocket, its roots sunk into the ash and in full bloom.
The scientists swiftly declared Surtsey a nature reserve to which they would control access. But from the first, the speed, ingenuity and sheer unpredictability of nature鈥檚 colonisation of Surtsey wrong-footed them.
Everyone guessed that the most visible early invaders would be lichens and mosses, brought by sea birds or blown on the winds from neighbouring Icelandic islands. No so. Instead it was flowering plants and grasses that took the lead. The sea rocket was no fluke. It settled in and was swiftly followed by lyme grass and sea sandwort, cotton grass and ferns. It was 1967 before mosses arrived, and lichens only limped aboard in 1970.
A further mistake was to assume that all the colonisers would be local Icelandic species. Far from it. Surtsey is the most southerly spot of dry land in Iceland. Keep going south and you hit nothing until Antarctica. So it is a welcome stopping point for migrating birds from mainland Europe and North America. Visiting geese and snow buntings, ravens and whooper swans bring seeds and insects from distant lands.
Snow buntings brought the seeds of bog rosemary from Britain in their gizzards. And while Surtsey鈥檚 first slugs and earthworms were Icelandic, many of the insects came from mainland Europe. This was an ecosystem created, in the first days, largely by accident. There was no complex evolutionary adaptation to the surroundings nor even a replication of ecosystems on neighbouring islands. What came, came.
So far, there are around 60 species of vascular plants on Surtsey, a similar number of lichens, and rather fewer mosses and liverworts. There may be 300 taxa of insects and hundreds more other invertebrates and microbes. The inert ash was invaded by cyanobacteria and nitrogen-fixing bacteria as early as 1970. Insects hitched rides on floating tussocks of grass or in birds鈥� feathers. Mites washed up first on a floating gatepost. Spiders came by air, lofted through the atmosphere on silken threads. Some flies are thought to have arrived in scientists鈥� lunch boxes. And a parasitic wasp came as a larva inside the body of the fly that plays host to it 鈥� which itself came over the sea from neighbouring islands.
鈥淏y the island鈥檚 first spring in 1964, it was no longer barren鈥�
But nobody guessed the big winner: the sea sandwort. Textbooks say this plant lives on dunes and around the edges of lagoons, from Alaska to Ireland to Siberia, not on outcrops of magma off Iceland. Yet here it is, now covering more than 60 per cent of the island.
The first birds nested on the island in 1970, producing chicks just three years after the lava stopped flowing. But these early arrivals were all seabirds such as fulmars and black guillemots. They kept to the cliffs, making nests of pebbles. They contributed little ecologically. Not so the gulls. In the summer of 1985, a pair of lesser black-backed gulls built a nest of vegetation and seaweed on the lava flats in the south of the island. They departed, but returned the following year with others and set up a permanent gull colony that now numbers more than 300 pairs.
Some feared the gulls would destroy what vegetation there was by tearing it up to make their nests. Wrong again. The gulls brought in scraps of vegetation from far and wide. And this airborne flotsam and jetsam, combined with the birds鈥� excreta and the occasional rotting carcass, seeded and fertilised the barren lava and ash. Soon the gull colony had created a bright green oasis on the southern tip of the island that has been spreading ever since. Within a decade, there was enough vegetation on the island for geese to come grazing. More recent arrivals include willow bushes and puffins.
Despite the somewhat haphazard arrival of species, says Borgthor Magnusson of the Icelandic Institute of Natural History, 鈥渙ne thing led to another and we now have a fully functioning ecosystem on Surtsey鈥�. The plants support insects that attract birds that bring more plants.
The best joke is that there are already fossils on Surtsey. It seems that the remains of molluscs and other creatures sealed into sedimentary rocks on the seabed were blasted into the air during the great explosions and helped build up the new island.
Islands like Surtsey leap up out of the ocean only very occasionally. Most underwater volcanic eruptions either happen too deep or produce too little material to form a land surface that is not instantly washed away. But Surtsey 鈥� one of a chain of volcanic islands south of Iceland that follow the Mid-Atlantic Ridge 鈥� was big. When the eruptions stopped, the island had a surface area of 2.7 square kilometres. And at its summit, the hard lava had solidified into a cliff face 154 metres high.
The island has excited geographers, who marvel that canyons, gullies and other land features that typically take tens of thousands or millions of years to form were created in less than a decade. And it has been visited by space scientists such as Jim Garvin from NASA, who sees it as the nearest equivalent on Earth to Mars. He says the steep-sided crater, flat plains of ash and other volcanic landforms created on Surtsey when magma met water are similar to those found on Mars. One day, he says, NASA may train Mars explorers on Surtsey to help them acclimatise to the kind of terrain they can expect.
They鈥檇 better be quick. Right now, Surtsey is eroding by about a hectare a year. The soft ash surface is vulnerable to the heavy Atlantic swells during winter storms, says geologist Sveinn Jakobsson, a board member of the Surtsey Research Society set up to oversee the island. Its surface area has halved since 1967, and Jakobsson reckons the ash plains will all be washed away within a century or so.
But he believes the hard lava core that forms the island鈥檚 summit will survive for thousands of years. One day, he says, Surtsey will probably come to resemble the many neighbouring cliff stacks of the archipelago. And that will be bad news for the colonists.
The ecosystem could disappear almost as quickly as it arose, says Magnusson. 鈥淲e expect that species numbers will continue increasing for the next 30 to 50 years. But after that the island will start to lose species as habitats are lost to erosion.鈥� Seabirds will continue to nest on the cliffs, but most of the unique ecosystem now thriving on the ash plains beneath will be washed away. Until the next eruption.
