Environmental Engineering Reference
In-Depth Information
The first birds nested on Surtsey in 1970. The first chicks hatched just three years after the lava
stopped flowing. These early arrivals were all seabirds such as fulmars and black guillemots. They kept
to the cliffs, making nests of pebbles, and 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 three hundred pairs.
Some of the scientists visiting the island feared the gulls would destroy the island's nascent vegeta-
tion by tearing it up to make their nests. Wrong again. The gulls brought in scraps of vegetation from far
and wide. And these airborne flotsam and jetsam, combined with the birds' excreta and the occasional
rotting carcass, seeded and fertilized the barren lava and ash. Soon the gull colony 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 for geese to come grazing. More recent arrivals include puffins. Willow bushes have
become established.
This was an ecosystem created largely by accident. “One thing led to another and we now have a
fully functioning ecosystem on Surtsey,” says Borgthor Magnusson of the Icelandic Institute of Natural
History, a regular visitor. The plants support insects that attract birds that bring more plants. There was
no complex evolutionary adaptation to the surroundings or even a replication of ecosystems on neigh-
boring islands. What came, came. Alien or native? Who knows or cares? This was nature doing its
thing—ecological fitting in action.
Islands like Surtsey leap up out of the ocean only rarely. Most underwater volcanic eruptions either
happen at too great a depth or produce too little material to form a land surface that is not instantly
washed away. But Surtsey was big enough to stay. When the eruptions stopped, the island had a surface
area of 1.2 square miles. And at its summit, the hard lava had solidified into a cliff face five hundred
feet high.
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The nearest modern parallel in terms of geological forces creating a new place for nature to colonize
is Krakatoa, an island in Indonesia that was virtually destroyed in a giant volcanic eruption in 1883. The
eruption blew the top off the island and destroyed virtually every living thing on it. But within sixty
years, Krakatoa had what Elton called a “rich and maturing jungle.”
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More than seven hundred species
of insects and thirty species of resident birds had moved in from the neighboring islands of Java and
Sumatra, along with bats, numerous insects, and reptiles such as snakes.
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Surtsey has excited geographers, who marvel that geological features such as canyons, gullies, and
other land features were created in less than a decade. It has been visited by NASA scientists who say
they may one day use it to train Mars explorers in handling the kind of terrain they can expect on the
red planet. But Surtsey won't be around for very long. Right now, it is eroding by about 2.5 acres a year.
The soft ash is vulnerable to the heavy Atlantic swells. The ecosystem could disappear almost as quickly
as it arose. “We expect that species numbers will continue increasing for the next thirty to fifty years,”
Magnusson tells me. “But after that, they will start to disappear as habitats are lost to erosion.” Seabirds
will continue to nest on the cliffs, but most of the unique ecosystem now thriving on the ash plains will
be washed away.
No sane person will argue that we should try to preserve this ecosystem. It will depart as it arose, a
product of random forces of geology, species migration, and ecological fitting. But in that, it is not so
different from the rest of the planet.
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