BIOREMEDIATION

What Is Bioremediation?
Bioremediation is the use of organisms to break down and thereby detoxify dangerous chemicals in the environment. Plants and microorganisms are used as bioremediators. The technology can take advantage of a natural metabolic pathway or genetically modify an organism to have a particular toxic "appetite."

Bioremediation can be defined as any process that uses microorganisms or their enzymes to return the environment altered by contaminants to its original condition. Bioremediation may be employed in order to attack specific contaminants, such as chlorinated pesticides that are degraded by bacteria, or a more general approach may be taken, such as oil spills that are broken down using multiple techniques including the addition of fertilizer to facilitate the decomposition of crude oil by bacteria.

Not all contaminants are readily treated through the use of bioremediation; for example, heavy metals such as cadmium and lead are not readily absorbed or captured by organisms. The integration of metals such as mercury into the food chain may make things worse as organisms’ bioaccumulate these metals.

However, there are a number of advantages to bioremediation, which may be employed in areas which cannot be reached easily without excavation. For example, hydrocarbon spills (or more specific: gasoline) may contaminate groundwater well below the surface of the ground; injecting the right organisms, in conjunction with oxygen-forming compounds, may significantly reduce concentrations after a period of time. This is much less expensive than excavation followed by burial elsewhere or incineration, and reduces or eliminates the need for pumping and treatment, which is a common practice at sites where hydrocarbons have contaminated groundwater.
Generally, bioremediation technologies can be classified as in situ or ex situ. In situ bioremediation involves treating the contaminated material at the site while ex situ involves the removal of the contaminated material to be treated elsewhere. Some examples of bioremediation technologies are bioventing, land farming, bioreactor, composting, bioaugmentation and biostimulation.

Compost is the decomposed remnants of organic materials (those with plant and animal origins). Compost is used in gardening and agriculture, mixed in with the soil. It improves soil structure, increases the amount of organic matter, and provides nutrients.
Compost is a common name for humus, which is the result of the decomposition of organic matter. Decomposition is performed primarily by microbes, although larger creatures such as worms and ants contribute to the process. Decomposition occurs naturally in all but the most hostile environments, such as buried in landfills or in extremely arid deserts, which prevent the microbes and other decomposers from thriving.
Composting is the controlled decomposition of organic matter. Rather than allowing nature to take its slow course, a composter provides an optimal environment in which decomposers can thrive. To encourage the most active microbes, the compost pile needs the proper mix of the following ingredients:

Carbon Nitrogen Oxygen (air) Water Decomposition happens even in the absence of some of these ingredients, but not nearly as quickly and not nearly as pleasantly (for example, the plastic bag of vegetables in your refrigerator is decomposed by microbes, but the absence of air encourages anaerobic microbes that produce disagreeable odors).

References:
Bolin, Frederick. "Leveling Land Mines with Biotechnology." Nature Biotechnology 17 (1999): 732.
Eccles, Harry. Bioremediation. New York: Taylor and Francis, 2001.
Hooker, Brian S., and Rodney S. Skeen. "Transgenic Phytoremediation Blasts onto the Scene." Nature Biotechnology 17 (1999): 428.
Lewis, Ricki. "PCB Dilemma." The Scientist 15 (2001): 1.


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Sunkanmi Rufai

Desertification: A Natural Disaster (...cont'd)

...continued from last post

PROBLEM
Desertification became well known in the 1930’s, when parts of the Great Plains turns into the “Dust Bowl” as a result of drought and poor practices in farming, although the term itself was not used until almost 1950.
“Dust Bowl” as result of drought
During the dust bowl period, millions of people were forced to abandon their farms and livelihoods. Greatly improved methods of agriculture and land and water management in the Great Plains Have prevented that disaster from recurring, but desertification presently affects millions of people in almost every continent. Increased population and livestock pressure on marginal lands has accelerated desertification. In some areas, nomads moving to less arid areas disrupt the local ecosystem and increase the rate of erosion of the land. Nomads are trying to escape the desert, but because of their land-use practices, they are bringing the desert with them. It is a misconception that drought cause desertification. Droughts are common in arid and semiarid lands. Well-managed lands can recover from drought when the rains return. Continued land abuse during droughts, however, increases land degradation. By 1973, the drought that began in 1968 in the Sahel of West Africa and the land-use practices there had caused the deaths of more than 100,000 people and 12 million cattle, as well as the disruption of social organizations from villages to the national levels.

CONTROL
Desertification can be controlled through effective management and policy approaches that promote sustainable resource use. Major policy intervention and changes in management approaches, both local and global levels, are needed in other to prevent, control, stop or reversing desertification. The creation of preventive measures that promotes alternative livelihood and conservation strategies can go a long way towards protecting drylands both when desertification is just beginning and when it is ongoing. It requires change in government and people’s attitude. Populations can prevent desertification by improving agricultural practices such as afforestation, shifting cultivation, crop rotation etc. and grazing practices in a sustainable way. Even once land has been degraded, rehabilitation and restoration measures such as controlling burning, alternative fuel source, fire traces etc., terracing prevents further gully erosion, pegging, ridges along slopes also check any further erosion and good irrigation system can help restore lost ecosystem services. The success of rehabilitation practices depends on the availability of policies and technologies and the close involvement of local communities. With all the causes and effects, desertification has poses one of the greatest environmental challenges today and constitutes a major barrier to meeting basic human needs. Effectively fighting desertification will help reduce global poverty and will contribute to meeting the Millennium Development Goals (MDGs).

REFERENCE
“Ecosystems and human well-being: Desertification Synthesis”, a report published in 2005 by the Millennium Ecosystem Assessment (MA)

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© Rufai Sunkanmi

Desertification: A Natural Disaster

The world’s greatest deserts were formed by natural processes interacting over long intervals off time. During most of these times, desert have grown and shrunk independent of human activities. In some regions, deserts are separated sharply from surrounding. In other areas, desert fringes form a gradual transition from a dry to a more humid environment making it more difficult to define the desert border. These transition zones have very fragile delicately balanced ecosystems. In these marginal arrears, human activity may stress the ecosystem beyond its tolerance limit, resulting in degradation of the land. This degradation of formerly productive land to barren land or a persistence degradation of dry land ecosystem by variation in climate and human activities is called DESERTIFICATION.

CAUSES
Desertification is a complex process which involves multiple causes as a result of “drought and poor practices in farming”. Also, an increase in population and livestock pressure on marginal land has accelerated desertification. In dryland, water scarcity limit the production of crops, forage, wood, and other services ecosystem provide to humans, still the increase in human pressures on the exploitation of plants both in dry lands and humid areas thereby leading to desertification is the major cause of desertification. It is also caused by a combination of social, political, economic and natural factors which varies from region to region. Water erosion and reduced soil conservation negatively affect ecosystem services. Policies that can lead to an unsustainable use of resources and lack of infrastructure are major contributor to land degradation. Agriculture can play either a positive or negative role, depending on how it is managed. Policies favouring” sedentary farming” (the act of staying in a particular area/land) over “nomadic herding” (the act of feeding animals) in regions more suited to grazing can contribute to desertification. The process of globalization both contribute to desertification and prevent it, for instance, in some cases, trade liberalization, economic reforms, and export oriented production in dry land can promote desertification. In other cases, enlarged markets outside of the drylands also contribute to successful agricultural improvement. Livelihoods have been based on a mixture of hunting, gathering, farming and herding. This mixture varied with time, place, and culture, since the harsh conditions forced people to be flexible in land use. Population growth has led to the extension of cultivated lands and the irrigation of these lands is brought about by desertification, as well as other environmental problems. Other causes include burning which also can turn vegetation to an exposed soil thereby leading to desertification. So also overtillage and erosion can have tremendous implication on the environment leading to loss of soil conservation, loss of nutrient and soil exposure.

DISASTER
Desertification has various disastrous effects on the environment because of its wide spread. It was reported that desertification affects the livelihood of millions of people, as it occurs in all continents (except Antarctica).Desertification takes place in drylands all over the world. Some 10 to 20% of all drylands may already be degraded, but the precise extent of desertification is difficult to estimate, because few comprehensive assessments have been made so far.

A large majority of dryland population lives in developing countries as population growth and increased food demands are expected to drive the expansion and intensification of land cultivation in drylands. If no counter measures are taken, desertification in drylands will threaten future improvement in human well-being and possibly reverse gains in some regions compared to the rest of the world; these populations lag far behind in terms of human well being, per capita income and infant mortality. The situation is worst in the drylands of Asia and Africa. Desertification has environmental impacts that go beyond the areas directly affected. For instance, loss of vegetation can increase the formation of large dust clouds that can cause health problems in the more densely populated areas, thousands of kilometer away. Desertification is also disastrous such that it diminishes biological diversity, a diversity which contributes to many of the services provided to humans by drylands ecosystems. Vegetation and its diversity are key for soil conservation and for the regulation of surface water and local climate. Desertification, however contributes to global climate change by releasing to the atmospheric carbon stored in dryland vegetation and soil. The effect of global climate change on desertification is complex and not yet sufficiently understood. On the one hand, higher temperatures resulting from increased carbon dioxide levels can have a negative impact through increased loss of water from soil and reduced rainfall in drylands. Desertification also affect products such as food and water, natural processes such as climate regulation, but also non-material services such as recreation and supporting services such as soil conservation. These can lead to unsustainable agricultural practice, further land degradation, exacerbated urban sprawl, and socio-political problems. Moreover, the social and political impacts of desertification also reach non-drylands areas. For example, human migration from drylands to cities and other countries can harm political and economic stability.

Next Post shall be addressing; Problem and Control.

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Sunkanmi Rufai