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Environmental remediation
The application of molecular biology to soil microorganisms is opening a new
world for soil microbiologists, who investigate the role of microorganisms in
soil and groundwater remediation. A recent example is the discovery and culture
of an organism that utilizes the gasoline additive MTBE (methyl tertiary-butyl
ether) as an energy source. The organism is now being introduced into polluted
groundwater on a military facility to determine the efficacy of this approach
to groundwater remediation. Bioreclamation of potentially toxic organic materials
such as perchlorate and chlorophenol are other examples of how soil microorganisms
are put to work to remedy environmental pollution.
Phytoremediation, the use of plants to remove toxic trace elements from soils
has been accelerated by the genomics and molecular biology revolution as well.
Now, in addition to isolating plants that are naturally adept at concentrating
metals, soil scientists and plant scientists are creating transgenic plants
that are more efficient phytoremediators than naturally occurring species.
Soil scientists are also helping to transform former approaches to waste and
its removal. Traditional disposal methods are giving way to new waste utilization
technologies, made possible by a thorough understanding of the properties of
biosolids (treated human waste). The use of biosolids in soil reclamation and
remediation is now common.
One concern with biosolids utilization is their trace-metal composition. Soil
scientists continue to make progress in understanding the distribution, reactivity
and fate of heavy metals in the environment. Soil, because of its high surface
area and reactivity, provides a critical filter that protects groundwater and
surface water from heavy-metal contamination. As they investigate the properties
of metallic elements such as chromium, cadmium, lead and copper, scientists
are able to apply their growing knowledge to soil remediation projects in order
to prevent the transfer of these and other metals to groundwater and surface
water.
Surface water quality is also affected by overland flow from urban and agricultural
watersheds. Soil scientists study the processes that move sediment, nitrogen,
phosphorus and pathogens into surface waters. New computer models are proving
useful in predicting where and when these pollutants will be transported from
watersheds to receiving water bodies so that effective soil conservation practices
can be implemented.
Carbon cycling and its role in global climate change is an important area of
soil science research. Carbon sequestration by soils has been shown to have
the potential to slow the increase in atmospheric carbon-dioxide concentration.
A major advance in farming systems now being widely adopted is the use of conservation
tillage, which reduces soil disturbance and increases the retention of recalcitrant
carbon that would otherwise be released to the atmosphere as carbon dioxide.
Soil scientists are also investigating the cycling of other greenhouse gases,
including nitrogen gases and methane, in order to develop methods for reducing
their production and release to the atmosphere.
Soil science research spans spatial scales from nanometer to kilometer and from
basic processes to practical applications. Every facet of human life is affected
by soil — from what we eat to where we live and how we dispose of waste.
Soil scientists contribute to our understanding of where resources exist, their
properties, functions and management. Although food production for a growing
population continues to be an important theme in much soil science research,
environmental research also drives the soil scientist's agenda.
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