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| ==Introduction== | | ==Introduction== |
| In the Global Warming Age, soil scientists are concerned about a loss of microbial diversity. Microbial populations thrive when they have unlimited space, food, and free energy. Such general requirements can be met in a plethera of different ways depending on the soil environment and physcial factors. This page is dedicated to the exploration of how the soil environment and physical factors control microbial activity.
| | This page explores the soil environmental factors regulating microbial activity. |
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| ==Key Points==
| | Warm-up with this quote by Shuhei Ono from the Carnegie Institution's Geophysical Laboratory: |
| ===Soil Structure/Environment===
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| -Soil Texture: Sand (0.05-2.0 mm) Silt (0.002-0.05mm) Clay ( < 0.002mm) Soils that are coarse textured are less likely to have a well-defined structure and therefore fewer structured pore space than s soil high in clay content.
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| - Soil pores play a major role in water and air movement. Also, soil microorganisms reside in pores. Pore space is largely determined by size and arrangement of aggregates and affects the movement of water, air, and organisms in soil.
| | “We think that there were microbes in the oceans, before the oxygenated atmosphere, which would have used methane for energy... |
| | Oxygen first appeared on the surface of the Earth when microbes developed the capacity to split water molecules to produce O2 using the Sun's energy. This is a bit advanced biochemistry, but we think this biological revolution emerged sometime before 2.7 billion years ago," he continued. |
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| - Pore Size Distribution: Macropores ( >75um) Mesopores ( 30-70um) Micropores ( 5-30um) Ultramicropores (0.1-5um) Crytopores ( <0.1um)
| | Reuters (2006, March 22). Climate Change And The Rise Of Atmospheric Oxygen. ScienceDaily. Retrieved March 4, 2008 from http://www.sciencedaily.com/releases/2006/03/060322140017.htm |
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| - Soil Structure: Aggregation of primary soil particles is a critical determinant of soil structure.Structure is strongly affected by climate, biological activity, density and continuity of surface cover, and soil management practices. Soils that are coarse textured are less likely to have a well-defined structure and therefore fewer structured pore space than s soil high in clay content. Ecological relationships among soil organisms are influenced by soil structure.
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| -aggrogates
| | ==Key Points== |
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| ===Soil Environment=== | | ===Chemical Factors=== |
| ====Abiotic factors====
| | macro nutrients (base extractable organic C), extractable P, nitrate & ammonium, ph & EC, ect |
| - Soil water is essential for soil microorganisms. Without some water, there is no microbial activity.
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| - Soil aeration measures how well a soil is oxygenated. Ideally, a well-aerated soil would have sufficient oxygen for the respiration of plant roots and the function of most aerobic microorganisms.
| | ===Physical Factors=== |
| | Soil type: texture, density/porosity, moisture, depth, color, age, ect. |
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| | ===Biological Factors=== |
| | Microbe/Microbe interactions, growth rates (plant measurements/microbial measurements), assimilation, soil/plant relationships, ect. |
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| - Soil temperature greatly influences the rates of biological, physical, and chemical processes in the soil. Within a limited range, the rates of chemical reactions and biological processes double for every 10 degree increase.
| | ==Current Research== |
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| - Toxins poisonous substance produced by living cells or organisms that is active at very low concentrations.
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| - Osmotic pressure is the hydrostatic pressure produced by a solution in a space divided by a semi-permeable membrane due to a differential in the concentrations of solute.
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| - pH is important because microorganisms and plants respond markedly to chemicals in their environment. Most soil microorganisms and plants prefer a near-neutral pH range of 6 to 7 because the availability of most soil nutrients is best in this pH range.
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| - Bioavailability - Bioavailability is the amount of a contaminant that is absorbed from soil.
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| ====Biotic factors====
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| Native vegetation
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| Microflora
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| Microfauna
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| Macrofauna
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| Anthropogenic (farming, ect.)
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| ==Current Research==
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| ==References== | | ==References== |
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Introduction
This page explores the soil environmental factors regulating microbial activity.
Warm-up with this quote by Shuhei Ono from the Carnegie Institution's Geophysical Laboratory:
“We think that there were microbes in the oceans, before the oxygenated atmosphere, which would have used methane for energy...
Oxygen first appeared on the surface of the Earth when microbes developed the capacity to split water molecules to produce O2 using the Sun's energy. This is a bit advanced biochemistry, but we think this biological revolution emerged sometime before 2.7 billion years ago," he continued.
Reuters (2006, March 22). Climate Change And The Rise Of Atmospheric Oxygen. ScienceDaily. Retrieved March 4, 2008 from http://www.sciencedaily.com/releases/2006/03/060322140017.htm
Key Points
Chemical Factors
macro nutrients (base extractable organic C), extractable P, nitrate & ammonium, ph & EC, ect
Physical Factors
Soil type: texture, density/porosity, moisture, depth, color, age, ect.
Biological Factors
Microbe/Microbe interactions, growth rates (plant measurements/microbial measurements), assimilation, soil/plant relationships, ect.
Current Research
References
Edited by students of Kate Scow
