Team:Imperial College London/Project/Background

From 2011.igem.org

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   title[3] = "China and Central Asia";
   title[3] = "China and Central Asia";
   title[4] = "Indian Himalayas";
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   text[0] = "Mouse over the map to read about the impact of desertification in different areas.";
   text[0] = "Mouse over the map to read about the impact of desertification in different areas.";
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   text[3] = "China is one of the largest dryland areas in the world, nearly a quarter of which is at risk of desertification. The problem has been fed by large-scale industrialisation with the over-use of land and water resources, as well as prolonged drought. Since 1978 the Great Green Wall project has been underway in the Kubuqi desert to protect cities from wind erosion carrying dust. The trees (Xinjiang poplars and willow species) are planted as saplings protected with wooden frames so they can take root before being blown away. These plants form fibrous roots that help hold down the sand. Although this project has slowed the desertification process in China, it remains an imminent problem.";
   text[3] = "China is one of the largest dryland areas in the world, nearly a quarter of which is at risk of desertification. The problem has been fed by large-scale industrialisation with the over-use of land and water resources, as well as prolonged drought. Since 1978 the Great Green Wall project has been underway in the Kubuqi desert to protect cities from wind erosion carrying dust. The trees (Xinjiang poplars and willow species) are planted as saplings protected with wooden frames so they can take root before being blown away. These plants form fibrous roots that help hold down the sand. Although this project has slowed the desertification process in China, it remains an imminent problem.";
   text[4] = "30% of landmass in India is comprised of drylands and desertification is leading to crop losses of up to 41% in eastern Himalayan areas, which are recognised as biodiversity hotspots. Communities living in the Himalayas are heavily dependent on the forest as a resource for fuel wood and for their livestock. Increasing deforestation is leading to soil erosion and interference with water courses which is likely to have a major affect on inhabitants of the Ganges Plain who rely on the forest to slow flash floods. Small scale charities such as the Berkely Reafforestation Trust are working with local organisations to re-establish indigenous tree populations. So far they have funded the locally initiated reforestation of about 1600 hectares of degraded land and provided training programs to promote sustainability.";
   text[4] = "30% of landmass in India is comprised of drylands and desertification is leading to crop losses of up to 41% in eastern Himalayan areas, which are recognised as biodiversity hotspots. Communities living in the Himalayas are heavily dependent on the forest as a resource for fuel wood and for their livestock. Increasing deforestation is leading to soil erosion and interference with water courses which is likely to have a major affect on inhabitants of the Ganges Plain who rely on the forest to slow flash floods. Small scale charities such as the Berkely Reafforestation Trust are working with local organisations to re-establish indigenous tree populations. So far they have funded the locally initiated reforestation of about 1600 hectares of degraded land and provided training programs to promote sustainability.";
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  text[5] = "In Australia, desertification and soil degradation are wide-spread problems in rangelands, particularly in the dry inner parts of the continent. They result from overgrazing of the land but also climate conditions and invasive animal species such as rabbits. Economic factors play a big role as pastoralism is mostly export and profit oriented. Land degradation has been was triggered by the arrival of European pastoralism and has been an ongoing problem for the last century.                                                                                                                                                                                                                        Source: Pickup, G. (1998) Desertification and climate change - the Australian perspective. Climate Research 11, pp.51-63.";
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Revision as of 13:42, 18 September 2011



Desertification

Desertification is the degradation of drylands which include arid, semi-arid and sub-humid areas. Drylands make up roughly 40 percent of the Earth’s land and are home to some two billion people, most of which live in developing countries. Dryland soil sustains a fragile ecosystem adapted to infrequent precipitation and dramatic temperature changes. Over-exploitation of dryland for cultivation and feedstock purposes renders the soil unproductive, forcing migration of communities in search of fertile land, leaving the unproductive land bare and vulnerable to erosive forces. A lack of food supply in many developing countries forces constant cultivation of land for short-term gain as well as deforestation to provide arable land.


Engineering bacteria to help fight soil erosion

In arid areas of the world soil erosion is a massive problem. It is caused by wind and rain sweeping away the fertile top soil and can eventually result in desertification.

Climate change and unsustainable farming practices are accelerating the rate of desertification to over 31,000 hectares/day. That’s 62, 000 football pitches in a day or half the size of the UK every year.

In ordinary circumstances the roots of well-established plants help to hold down the top soil, protecting it from erosion. In areas that suffer desertification however plants do not get the chance to establish large enough root networks to anchor the soil and themselves before erosion occurs.

This year, Imperial College’s iGEM team have joined the international effort to fight desertification.

We hope to engineer bacteria to accelerate plant root development. The bacteria will be designed to secrete the hormone auxin. Seeds will be coated with the bacteria and then planted in the soil. Once the seeds germinate the bacteria will move towards the roots and be taken in by the plant. Inside the roots the bacteria will release auxin – promoting growth and protecting the soil from erosion.

Case Studies

Desertification
Mouse over the map to read about the impact of desertification in different areas.

Downstream Effects

Soil affects the climate and biodiversity and leads to often irreversible desertification (see figure above). Roots increase the stability of soil and prevent erosion (Gyssels & Poesen, 2003). In addition, trees provide cover and protect nearby fauna and flora. In areas prone to soil erosion, this is especially important as rainfall tends to be rare but when it does occur, it is often very intense and easily leads to topsoil being washed away. Roots are also important carbon sinks. Increasing root biomass is therefore very likely to improve the carbon budget of the plants we are seeding (Dr Alexandru Milcu, oral communication).

UN, Ecosystems and human well-being - Desertification synthesis.

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