w orldwatch n Did a Google Maps error spark Nicaraguan invasion?: Reports that an error on Google Maps was to blame for Nicaraguan troops invading and occupying a Costa Rican island were being questioned as Geographical went to press.

n early November, around 50 Nicaraguan soldiers set up camp on Isla Calero, a small island located in the delta of the San Juan River on the Atlantic coast. The soldiers lowered the Costa Rican flag and replaced it with a Nicaraguan flag.

When questioned about the incursion, the group’s commander, Eden Pastora, told Costa Rica’s largest newspaper, La Nacion, that Google Maps was to blame, pointing out that the map on the site clearly placed the island on Nicaragua’s side of the border. Nicaraguan government officials repeated the claim that a ‘bug in Google’ was at fault.

owever, several weeks after the incursion, the soldiers were still occupying the island, and doubts were being raised about the seriousness of the original explanation. Suggestions for an alternative included attempts by Nicaragua’s president, Daniel Ortega, to hold on to power, and a plan by Venezuela, Iran and Nicaragua to create a ‘Nicaragua Canal’ between the Atlantic and Pacific oceans.

he San Juan River marks the eastern third of the border between Nicaragua and Costa Rica; the river itself belongs to Nicaragua, and Costa Rica’s territory begins at its southern bank. Not long before the invasion, Ortega argued that the island should belong to his country, since Nicaragua owns the river and the island is made up of silt from the river.

n New crust being formed in novel way: Scientists at the Woods Hole Oceanographic Institution (WHOI) have observed ocean crust forming almost ten times farther away from an active ocean ridge than previously recorded.

cean crust is usually formed as magma bubbles up through volcano-like openings in a narrow (about five-kilometre-wide) zone along the boundaries between two plates that are pulling away from each other. Working at the Guaymas Basin in the Gulf of California, the WHOI scientists used a sound-wave-emitting air gun, side-scan sonar and ocean-floor cameras to confirm that magma was forming sills within the top one or two kilometres of the thick layer of sediment that fills the basin, about 50 kilometres away from the plate boundary.

he process has important implications for the local marine life, as well as the carbon cycle. The heat from the rising magma releases nutrient-rich fluid from within the sediments that is feeding communities of sea creatures similar to those found around vent sites near deep-water mid-ocean ridges. It also causes the release of significant amounts of carbon from the sediments – around ten times more carbon dioxide and methane than a similar volume of volcanic rock emerging from a vent.

he researchers suspect that the phenomenon is not restricted to the Gulf of California, but is almost certainly taking place in other sites.

Woods Hole Oceanographic Institution scientist examines a sample of ocean crust

Magma movement caused Icelandic eruption

The reawakening and subsequent eruption of Iceland’s Eyjafjallajökull volcano in March and April last year may have been triggered by the explosive meeting of two types of magma flowing beneath the volcano, according to an international team of scientists.

n a paper published in Nature, the researchers describe their analysis of geophysical changes that took place in the long-dormant volcano prior to its eruption. ‘Several months of unrest preceded the eruptions, with magma moving around downstairs in the plumbing and making noise in the form of earthquakes,’ said one of the study’s authors, Kurt Feigl of the University of Wisconsin-Madison.

The researchers used a combination of satellite imagery and GPS surveys to track the deformation of the volcano’s edifice. The results showed that the volcano swelled for 11 weeks before it first began to erupt, expanding by more than 15 centimetres as magma flowed into shallow chambers beneath the mountain.

fter the initial eruption, the researchers believe that the fresh magma came into contact with a different type of magma, perhaps left over from the last eruption, which took place 200 years ago. The differences in temperature, composition and gas content probably triggered the more explosive second eruption.

The researchers are now using data from an array of sensors around the volcano to map the chambers and other structures within it. ‘We’re a long way from being able to predict eruptions, but if we can visualise the magma as it moves upwards inside the volcano, then we’ll improve our understanding of the processes driving volcanic activity,’ Feigel said.

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12 www.geographical.co.uk january 2011 w orldwatch n Reforestation leads to the export of deforestation: Efforts to conserve forests in many developing nations has led to deforestation in other countries, according to a new study published in the Proceedings of the National Academy of Sciences.

team led by Patrick Meyfroidt of the Catholic University of Louvain in Belgium analysed the relationship between reforestation at the national scale and international trade in forest and agricultural products between 1961 and 2007, focusing on six developing countries that underwent a shift from net deforestation to net reforestation during that period: China, Chile, Costa Rica, El Salvador, India and Vietnam.

With the exception of India, in all of these countries, the return of native forests was accompanied by a reduction in timber harvests and the creation of new farmland over the same period, thus creating demand for imported wood and agricultural products. According to the study, this meant that for every 100 hectares of reforested land, the equivalent of 74 hectares of forest products were imported. Taking into account the countries’ exports of agricultural products, the net imbalance came to 22 hectares of land used in other countries. But during the past five years, that figure rose to 52 hectares, so for every hectare of land reforested, half a hectare was used elsewhere.

‘If local forest protection merely shifts forest-conversion pressure to natural forests elsewhere in the world, we won’t achieve a net gain for nature at a global scale,’ said one of the study’s authors, Eric Lambin. ‘However, this study doesn’t imply that the efforts of these countries to protect their forests was useless, but that international trade in wood and agricultural products can decrease the global environmental benefits of national forest-protection policies.’

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Vacant lots could feed Detroit A new study by researchers at Michigan State University suggests that transforming vacant urban lots in Detroit into farms and community gardens could satisfy the majority of the city’s residents’ fruit and vegetable needs.

The collapse of Detroit’s manufacturing industry and subsequent urban flight has left the city with large areas of vacant land. As part of the study, the researchers catalogued available land without existing structures. Using aerial imagery and the city’s database of vacant property, they identified more than 44,000 available parcels of land, covering an area of almost 2,000 hectares. This land, if turned over to a combination of urban farms, community gardens, storage facilities and hoop houses – greenhouses used to extend the growing season – could satisfy three quarters of the local demand for vegetables and 40 per cent of the demand for fruits, the researchers calculated.

‘What’s clear from our analysis is that even with a limited growing season, significant quantities of fresh fruits and vegetables eaten by Detroiters could be grown locally,’ said Kathryn Colasanti, the graduate student who led the study, which was published in the Journal of Agriculture, Food Systems, and Community Development. ‘And investments in produce storage facilities and hoop houses would increase this capacity substantially.’

In brief

MAURITANIA Scientists have discovered an extensive cold-water coral ecosystem off the coast of Mauritania. Located on the continental shelf at a depth of around 615 metres, the coral wall is 50–60 metres high and 190 kilometres long.

ICELAND Results from a genetic study of a family in Iceland suggest that the first Americans arrived in Europe 1,000 years ago. The researchers who carried out the study have hypothesised that a particular set of genes found in the family arrived in Iceland when an Amerindian woman was taken from North America by the Vikings some time around 1000 AD.

AFRICA Health campaigners have expressed optimism that meningitis could soon be brought under control in Africa thanks to the development of a cheap vaccine. The vaccine, which costs 30p a dose to produce, was developed by the World Health Organization and Seattle-based non-profit group Path.

PANAMA The Panama Canal and Panama City are at risk of a devastating earthquake, according to new research. As part of a seismic-hazard study in preparation for the expansion of the canal, researchers found evidence that two faults that pass under it are seismically active and last ruptured in a large earthquake in 1621.

MEDITERRANEAN Scientists have traced the distinctive red ‘terra rossa’ soil found around the Mediterranean in places such as Mallorca and Sardinia to the Sahara and Sahel. The dust appears to have been blown over the region between 12,000 and 25,000 years ago.

january 2011 www.geographical.co.uk 13