You are a hard rock geologist with a fascination for the early stages of soil formation – where would you chose to go? Iceland, obviously! Not only are there miles of exposed rock, but the rock is very young, the climate is harsh and vegetation is sparse.
The island that represents the only place in the world where a mid-ocean plate margin exists above sea level. The only place where a hot spot combines with a plate margin. The ultimate geologists dream. The image on the left shows the plate margin stretching across the landscape as a small ridge cracked open, and near here used by the locals as a naturally heated swimming pool. For the benefit of tourists, a wider cleft near the south coast is spanned by a small footbridge bearing the label shown on the right – you cross the bridge from North America to Europe, geologically speaking.
But it is also a place where the Ice Age still exists, with Europe’s largest icecap sending glaciers to calve icebergs at sea level into a lake impounded by a terminal moraine but barely connected to the sea. DUKWs take visitors out into the lake amongst the icebergs and to the snout of the main ice cap. The sea water keeps the lake from freezing, though artifiically damming the outlet did allow it to freeze for the filming of a James Bond movie.
And on top of all of this, farmers trying to eke out a living on soils so fragile that they barely exist over most of the island. So, in 2003 I spent nearly three weeks touring the island, looking at geology, soils and farming. In 2005 I returned to examine some areas in more detail, including the geothermally heated glasshouses growing amongst other more mundane crops, bananas.
Iceland was born some 14 million years ago as massive basaltic volcanoes burst through sea level and began outpouring vast lava flows that still make up the extreme east and west of the island. Between eruptions, weathering oxidised the surface, altering minerals into clay and forming primitive soils. Subsequent eruptions baked these early soils which now look like layers of brick-red fired clay between the lava flows [left – seen in many places around the island].
Eruptions have continued ever since, with a myriad of small craters, like this one at Grabrok [right – one of the larger of the small isolated craters] spreading lava flows all over the island. Major volcanoes can cause mayhem, Hekla in 2000 erupted covered the icecaps with a layer of black ash and contribute yet more debris to the inland deserts – it also produced large amounts of white pumice that covers the nearby areas like a dusting of snow. The Lakki fissure which erupted in 1783 was possibly the world’s last “super-volcano” to erupt, not on the scale postulated for Yellowstone with global destruction in its wake, but nevertheless injecting enough dust and sulphuric acid into the atmosphere to create mayhem with crop failure, snow and ice falls in summer right across Europe and up to one third of the population of Iceland died of starvation and respiratory diseases. And we all know what happened at Easter 2010……
The inland area is a cold desert, largely bare of vegetation and whipped by icy winds. There is something really eerie about black sand dunes, especially when capped by lyme grass [which really is lime green in colour], akin to pampas grass or miscanthus, which has also been used on the sandy deserts and is spreading slowly across, stabilising the dunes.
Lupins [dcp05037] have also been planted extensively, often in strange strips meandering across the interior, to introduce nitrogen and “kick start” soil development. However the exotic lupins have been too successful and are now spreading into areas of native tundra vegetation and are considered a weed to be eradicated.
The new volcano Eldfell, on the Westman Isles is heralded as the world’s youngest mountain [dsc00694] after it erupted in 1973, creating some 3 square miles of new land [dsc00707]. This new land is still bare, but the flanks of the mountain have been seeded and planted quite successfully to prevent wind erosion Surtsey, sadly closed to visitors, is being treated as a natural laboratory for studies of colonisation following its formation on 14th November 1963. However it doesn’t take much imagination to piece together the general sequence of colonisation and soil formation by looking at a time sequence of lava flows and ash deposits on Iceland itself.
On November 5th 1996 the latest catastrophic flood or jokulhlaup in a long series, washed away the main road along the south coast[dcp5620] several bridges, and isolated the eastern half of the island for months. Some 3000 billion litres of water carried some 100 million tons of sediment to extend the land some several kilometres out to sea. Naturally, the south coast is largely uninhabited due to these frequent floods that are more devastating locally than a tsunami and leave a landscape of vegetation-free sands and gravels [dscn3521], very reminiscent of what the whole country would have looked like during the ice age.
Soils on this violent island vary from wonderfully deep, organic, nutrient rich soils under natural vegetation [dscn3526] on basaltic ash around the coast and in alluvial areas [dscn3062], to dry, dusty cold deserts in the interior. Periglacial conditions still exist away from the coast with amazing examples of “patterned ground” [dcp04799] where stones are separated from the finer soil and arranged in stripes or nets, whilst in other areas large mounds typical of arctic cryosols have developed [dcp05015].
But what of agriculture? The island was colonised in 840 AD when the Vikings arrived from Norway. Few countries can accurately date their origin and measure the impact of man on the environment with such precision. About 25% of the country was forested, but the Vikings [dcp04651] began deforestation immediately, clearing scrub birch woodland for fuel, for building material and to repair their ships. Before long the island was completely deforested, and even today I met people who were brought up to believe that “trees just don’t grow on Iceland.” Fortunately, there have been extensive attempts are replanting [dscn 3700], and trees now grace much of the island, though the only “forest” is a plantation in the east, and there are still vast expanses without a tree for miles. The soils, fragile at best, suffered extensive erosion, with large expanses of bare subsoil, deep gullies, and blowing sand. There have been considerable attempts at replanting, especially on the south coast to stabilise the glacial outwash plains and inland to stabilise the cold sand deserts.
Farms are predominantly livestock, cattle round the coast and sheep further inland. Everywhere is littered with big bale silage [dscn2792], usually wrapped in white plastic, looking like a fall of giant hailstones. Drainage is common, with up to 2m deep ditches [dscn2798]. Cattle suffer terribly from mosquitoes and other flies – anyone who has been near Lake Myvatn will know of the swarms of biting insects that force almost everyone to wear “mossi-nets”. Finding a cow wearing a mossi-net on its udders – well, what luxury!
Some farmers grow forage crops, even cereals, but the green areas are predominantly silage grass fields.
Of course what excites me most is this is a land where green vegetables are traditionally unheard of! Even now, with much food imported and the development of geothermally heated glasshouses, it is rare to find vegetables on the menu. Fish, meat, potatoes – a wonderful diet. Hveragerdi – literally “hot garden” – is set amongst a geothermal field and hosts the “Eden Centre”, no not like Cornwall’s excellent biodomes, more like a garden centre, but does demonstrate that a wide range of tropical plants can grow in the rich soils provided the natural climate is held at bay. I hadn’t really expected to be photographed looking at bananas even if I do frequently joke to students that they will be the first sign of global warming really affecting agriculture!
So what did I learn? Well, for a start it is vital to have seen or experienced for real the situations one teaches about. To see the evidence of recent volcanic eruptions, to experience the Ice Age, to see soils in the very earliest stages of formation are as important as research activity. To observe “farming on the edge” but at the same time to witness the exploitation of renewable energy for heating, power generation and high tech food production in country that has pledged to be carbon neutral and fossil fuel free as soon as possible makes the teaching of sustainable development so much more credible.