[Image: A photomicrograph of sand grains].

These chains seem to behave like the soaring arches of Gothic cathedrals, which serve to transmit the weight of the roof, perhaps a great dome, outward to the walls, which bear the load.

Most of today's active sandy deserts are surrounded by vast stretches of old stabilized dunes, formed as the trade-wind belts and arid regions expanded in the cold, dry climate of the last ice age and immobilized as the climate changed. However, continuing shifts in the climate may bring these fixed ergs, granular reserves awaiting activation, back to life.

The hills were stabilized eight hundred years ago but have had episodes of reincarnation since: a long drought toward the end of the eighteenth century resuscitated dunes on the Great Plains, whose activity caused problems for the westbound wagon trains decades earlier.

I researched different types of construction methods involving pile systems and realised that injection piles could probably be used to get the bacteria down into the sand – a procedure that would be analogous to using an oversized 3D printer, solidifying parts of the dune as needed. The piles would be pushed through the dune surface and a first layer of bacteria spread out, solidifying an initial surface within the dune. They would then be pulled up, creating almost any conceivable (structurally sound) surface along their way, with the loose sand acting as a jig before being excavated to create the necessary voids. If we allow ourselves to dream, we could even fantasise about ways in which the wind could do a lot of this work for us: solidifying parts of the surface to force the grains of sand to align in certain patterns, certain shapes, having the wind blow out our voids, creating a structure that would change and change again over the course of a decade, a century, a millenium.

Traditional anti-desertification methods include the planting of trees and cacti, the cultivation of grasses and shrubs, and the construction of sand-catching fences and walls. More ambitious projects have ventured into the development of agriculture and livestock, water conservation, soil management, forestry, sustainable energy, improved land use, wildlife protection, poverty alleviation, and so on. This project, apart from utilising a completely new way of turning sand into sandstone, incorporates all of the above. Inside the dunes, we can take care of our plants and animals, find water and shade, help the soil remain fertile, care for the trees, and so on. In this way, it's an environmental project that hopefully provides an innovation for other architects/builders to use and copy time and time again.

[Images: Synthesizing rare earth compounds – bioterrestriality; from Magnus Larsson's Dune: Arenaceous Anti-Desertification Architecture].

[Image: The view from within; from Magnus Larsson's Dune: Arenaceous Anti-Desertification Architecture].

For an ambitious landscape design project, Magnus Larsson, a student at the Architectural Association in London, has proposed a 6,000km-long wall of artificially solidified sandstone architecture that would span the Sahara Desert, east to west, offering a combination of refugee housing and a "green wall" against the future spread of the desert.Larsson's project deservedly won first prize last fall at the Holcim Foundation's Awards for Sustainable Construction held in Marrakech, Morocco.One of the most interesting aspects of the project, I think, is that this solidified dunescape is created through a particularly novel form of "sustainable construction" – that is, through a kind ofIn other words, Larsson has proposed using bacillus pasteurii, a "microorganism, readily available in marshes and wetlands, [that] solidifies loose sand into sandstone," he explains.Larsson points out the work of the Soil Interactions Lab at UC-Davis, which describes itself as " harnessing microbial activity to solidify problem soils."But the idea of taking this research and applying it on a megascale – that is, to a 6,000km stretch of the Sahara Desert – boggles the mind. At the very least, the idea that this might be deployed for the wrong reasons, or by the wrong people, in some delirious hybrid of ice-nine , J.G. Ballard's The Crystal World , and perhaps a Roger Moore-era James Bond film, deserves further thought.An epidemic of bacillus pasteurii infects all the loose sand in the world, forming great aerodynamic fins and waves in a kind of global Utah of glassine shapes.Clarifying the biochemical process through which his project could be realized, Larsson explained in a series of emails that his "structure is made straight from the dunescape by flushing a particular bacteria through the loose sand... which causes a biological reaction whereby the sand turns into sandstone; the initial reactions are finished within 24 hours, though it would take about a week to saturate the sand enough to make the structure habitable."The project – a kind of bio-architectural test-landscape – would thus "go from a balloon-like pneumatic structure filled with bacillus pasteurii, which would then be released into the sand and allowed to solidify the same into a permacultural architecture."The "architectural form" of the resulting solidified sandscape is actually "derived from tafoni ," Larsson writes, where tafoni is "a cavernous rock structure that formally ties the project back to notions of aggregation and erosion. On a conceptual scale, the project spans some 6,000km, putting it on a par with Superstudio's famous Continuous Monument – but with an environmental agenda."I'm reminded of Michael Welland's recent book Sand . There, Welland describes "how deserts operate" (he compares them to "engines" of mechanical weathering); he points out that you can still find "sand-sized fragments of steel" on the D-Day beaches of Normandy, war having left behind a hidden desert of metal; and he mentions that the UK now maintains "the world's first database of sand" – but that it's used "specifically for police forensics."Welland's descriptions of sand dune physics are particularly memorable. He writes, for instance, that an avalanche is really a sand dune being "overwhelmed by the huge number of very small events" on its surface, and that these "very small events" unpredictably lead to one decisive moment of cascading self-collapse.Fantastically, though, and more relevant to this post, he then compares the internal structure of sand dunes to Gothic cathedrals: the grains of sand piled high form "microscopic chains and networks... in such a way that they carry most of the pressure from the weight of the material above them." This is the architecture of sand:Briefly, though, this image can be sustained through Welland's descriptions of the great ergs , or sand seas, of today. These dune seas "are tangibly mobile, ever changing," Welland writes, "but there are larger areas of ergs past that are now fixed by vegetation."He mentions the Sand Hills of northwestern Nebraska, "formed originally from the debris of the glacial erosion of the Rocky Mountains."But if sand dunes are Gothic cathedrals, and if those dunes can come back to life, the resulting image of resuscitated Gothic cathedrals moving slowly over the American landscape is almost too incredible to contemplate.Larsson's project descriptions maintain this somewhat hallucinatory feel:A vast 3D printer made of bacteria crawls undetectably through the deserts of the world, printing new landscapes into existence over the course of 10,000 years...Larsson goes on to contrast his method with existing vernacular techniques of anti-desertification:The following images show us the lab-based biochemical practices through which a landscape can be lithified . However, for me at least, these photos also come with the interesting implication that rogue basement chemists of the future won't be like Albert Hofmann or Ann Alexander Shulgin ; the heavily regulated underground rogue chemistry sets of the 21st century will instead synthesize new terrestrial compounds, counter-earths and other illegal geosimulants, rare earth anti-elements that might then catalyze a wholesale resurfacing of the world through radical landscape architecture.Which leads me to ask: where is landscape architecture's Aleister Crowley Madame Blavatsky , or even John Dee ? Mystics of terrestrial form, hacking the periodic table of the elements inside makeshift labs.In any case, Larsson's "solidified dunes," we read, would also "support the existing Green Wall Sahara initiative: 24 African countries coming together to plant a shelterbelt of trees right across the continent, from Mauritania in the west to Djibouti in the east, in order to mitigate against the encroaching desert."Clearly having thought through the project in extraordinary detail, Larsson then points out that the structure itself would generate a "temperature difference between the interior of the solidified dunes and the exterior dune surface." This then "makes it possible to start building a permacultural network, the nodal points of which would support water harvesting and thermal comfort zones that can be inhabited."Eventually, then, a 6000km-long wall of permaculturally active, inhabited architecture will span the Sahara.Check out more images in this Flickr set for the project, or read a bit more about the project over at the Holcim Foundation