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Team:Imperial College London/Project/Background
From 2011.igem.org
Desertification
Soil erosion and desertification are world-wide problems. They lead to loss of arable land, economic hardship and environmental degradation. Our project focuses on tackling these serious problems by engineering bacteria to enhance plant root growth. We are planning to plant trees covered in a seed coat containing our bacteria. The trees will help hold down the soil in areas that are in danger of soil erosion and prevent degradation of top soil and resulting desertification (find out more about the specifics on our Implementation page).
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.
Case studies
Downstream Effects
Soil affects the climate and biodiversity and often leads to irreversible desertification (Fig. 1). Roots increase the stability of soil and prevent erosion [7]. 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.
Figure 1: The interplay between desertification, climate change, and biodiversity loss. Image taken from the Millenium Ecosystems Assessment - Desertification synthesis [1].
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).
References:
[1] Millenium ecosystem assessment (2005) Ecosystems and human well-being: Desertification synthesis. World Resources Institute, Washington, DC.(Online) Available from: http://www.maweb.org/documents/document.355.aspx.pdf
[2] Pickup G (1998) Desertification and climate change - the Australian perspective. Climate Research 11: 51-63.
[3] UNCCD (2011) Desertification: a visual synthesis. (Online) Available from: http://www.unccd.int/knowledge/docs/Desertification-EN.pdf (Accessed on 12 August, 2011).
[4] Science Daily (2007). Severity of desertification on world stage. (Online) Available from: http://www.sciencedaily.com/releases/2007/06/070619180431.htm.
[5] The Encyclopedia of the Earth (2010). Desertification. (Online) Available from: http://www.eoearth.org/article/Desertification?topic=49461
[6] Food and agriculture organisation of the United Nations. Desertification. (Online) Available from: http://www.fao.org/desertification/default.asp?lang=en
[7] Gyssels G and Poesen J (2003) The importance of plant root characteristics in controlling concentrated flow erosion rates. Earth Surface Processes and Landforms 28: 371-384.
