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Environmental Studies Ch. 10, 11, 12, & 14, Ch. 10: Water - Hydrologic…
Environmental Studies Ch. 10, 11, 12, & 14
Ch. 10: Water - Hydrologic Cycle and Human Use
The earth is about 75% water, 2.5% which is freshwater (water with salt concentration below 0.1%).
Water has special properties that make it unique to all other substances on earth. It has a high heat capacity, boiling point, melting point, vaporization point, freezing point.
Hadley Cells form from two halves of rising and falling air. The effect is similar to the effect of wind being present on the beach (cool air from the ocean moves under rising warm air on the beach while rising warm air moves over the ocean, creating a cycle).
Moist, warm air over the equator releases moisture as it ascends, creating a rainforest biome. It then moves toward slightly cooler regions away from the equator, and since it is now dry, it absorbs moisture. The cycle continues.
Rain shadows occur because of warm, wet air being pushed up a mountain side. As altitude increases, the water condenses into precipitation, and the air continues over the backside of the mountain. As the air is now dry and warm, it creates a rain shadow on the backside of the mountain.
Water is purified during its evaporation and condensation cycle. Water evaporates from bodies of water or transpired from the leaves of vegetation.
Water is absorbed into the ground through infiltration. The amount of water that soaks into the ground to the water that runs off is the infiltration-runoff ratio.
Water will either be contained by the soil in the form of capillary water or it will undergo percolation. During percolation, it will eventually reach a dense layer of earth that turns the water into groundwater.
Aquifers hold 99% of all liquid freshwater. These occur underground between layers of porous material. During percolation, the water is purified, so this water is generally safe to drink.
About 70% of the world's freshwater is used for irrigation, 20% for industry, and 10% for household use.
Within the home and industry, most of this water is reused. These are considered nonconsumptive water uses as the used water can be treated and used again.
Irrigation is a form of consumptive water usage as it is used only once and does not return to the local water source.
Water being overdrawn from aquifers leads to land subsidies and sinkholes. Since it takes natural precipitation to recharge these aquifers, water must be drawn at a sustainable rate to prevent damage to the system.
Water can also be purified during desalination, which is the process of converting salt water to potable drinking water.
Ch. 11: Soil - The Foundation for Land Ecosystems
Soil is solid material of geological and biological origin that is changed by chemical, biological, and physical processes, giving it the ability to support plant growth.
Other uses include an engineering medium, organism habitat, recycles nutrients and water, water purification, and a modifier of the atmosphere.
Five soil forming factors: 1. Climate, 2. Biota (1 & 2 are the most intertwined), 3. Parent Material, 4. Topography, and 5. Time. Human activity and human culture could be considered the sixth factor.
Soil is composed of 45% mineral particles, 25% water, 25% air, and 5% organic material (that 5% is made up of 80% humus, 10% organisms, and 10% roots). Three main categories are sand, silt, and clay (from largest to smallest particle size respectively).
The workability of the soil depends on its composition. Loam, which has decent drainage yet the ability to retain nutrients, tends to be ideal for agriculture.
Soil Horizons
O: organic layer, or humus made from decomposing plant matter and surface litter (not soil).
A: mineral horizon darkened by organic matter from above.
E: leached layer due to water movement.
B: zone of accumulating minerals like iron and aluminum oxides.
C: weathered parent material (partly broken-down minerals). Technically the least-weathered layer.
R: bedrock (not soil).
Water is trapped within small pockets of the soil in pore spaces, allowing the soil to remain moist. Good soil also needs proper aeration and nutrient holding capacity.
The macronutrients needed for plant growth are C, H, O (air and water), Ca, Mg, N, P, K, and S. The micronutrients are Cu, Fe, Mn, Ni, Zn, B, Cl, and Mo.
Good soil requires humus, near-neutral pH, and low salt content (phytotoxic). Fertilizers, both organic and inorganic, can be added to soils to provide necessary structure and nutrients.
Soil erosion is one of the most destructive forces on the planet, and it can bring down civilizations. It's caused by wind and water, but usually instigated through agriculture, industry, and mining.
Different forms of soil erosion include splash, sheet, rill, and gully erosion. Splash is from water hitting the soil and relocating it, sheet is when pools of water carry shift bodies of soil, rills are formed when water continually flows into a basin, and gullies are extreme versions of rills.
To prevent erosion, practices such as minimum or no-tillage, cover crops, crop rotations, contour strip cropping, soil amendments, and shelterbelts have been used.
Ch. 12: The Human Population and Essential Resources
Subsistence agriculture involves farmers that plant and harvest only what is needed to keep their families sustained. The only issue is that they do not do well when the crops fail, causing them to resort to imported goods.
Modern agriculture is a seriously large business, and it's power to destroy forests to grow crops is unprecedented. The use of chemicals, heavy machinery, and confined animal feeding operations takes a large toll on the health of the environment.
While biofuels seem like a promising solution to power the machinery, land used to grow food must be sacrificed to grow the stock for biofuel.
With the help of GMOs and Marker-assisted breeding, traditional growing methods can be improved, which gives larger yields in a shorter amount of time.
Like all good things, GMOs come with a cost. They have the potential to influence the evolution of pests to become capable of overcoming the unfavorable conditions set before them. People may also begin to experience more allergic reactions due to the fact that there is DNA from multiple plants packed into a single plant.
While GMOs have possible downsides, they may the only feasible solution in terms of feeding the global population.
With roughly 8 billion people, the amount of food that will be needed to combat hunger is a serious need. It's possible that international trade falls short to a food crisis, causing prices of food to rise.
Some smaller nations have been able to thrive during the economic shift from independent national economies to a globalized economy due to the exportation of goods.
With the help of subsistence, the nations, and the international community, the hunger needs can be met. This will ensure that everyone has proper nutrition and nourishment.
Countries that once survived off of subsistence farming are capable of growing cash crops and making enough profit to continue supporting themselves.
Sustainable agriculture methods such as drip irrigation, no till or minimum till farming, crop rotations, and vertical farming are all feasible methods.
Ch. 14: Fuel and Energy
The U.S. is still heavily dependent on the use of fossil fuels, particularly coal, to generate electricity. While it is currently sufficient, it is not a sustainable method that can be used for a long period.
Coal is gather via surface strip mining and underground mining methods. The consequences are somewhat drastic, ranging from a changed landscape, climate change, air pollution, acid mine drainage, and coal combustion byproducts.
91% of the coal gathered in the U.S. is used for the production of electricity.
Coal Combustion Byproducts
Bottom ash: ash particles that accumulate at the bottom of the combustion chamber after burning coal. It is reused for things like filler material, concrete additives, and snow and ice traction.
Boiler slag: molten bottom ash that has reacted with water. Reused in roofing grit, filler for asphalt, and raw material for concrete production.
Flue gas desulfurization material: formed from the scrubber stacks. Material is reused for wallboard, filler material for embankments, feed stock for cement, and raw material for concrete and grout products.
Fly ash: powdery material that rises with flue gas. Reused in concrete and grout products, an ingredient in soil modification or stabilization, component of road bases, and mineral filler in asphalt.
Natural gas is another form of energy that is harvested. It is primarily gathered through the use of fracking, which is high-pressure fluid being injected into pockets of shale, releasing the gas trapped in between.
Petroleum oil is still one of the suppliers of energy to date. However, it still contributes to climate change, and 65% of it is held in the Persian Gulf.
Oil shale yielding kerogen and oil sands yielding bitumen have also been used for the sake of creating power. Neither one is quite as efficient as petroleum oil, and oil sands create a lot of environmental damage.
Nuclear power appears to be promising in terms of efficiency and having clean byproducts.
Via nuclear fission, atoms can be split apart, releasing a massive amount of energy in the form of heat, which can then be used to power steam turbines to generate electricity.
While it is extremely efficient, it does create radioactive waste, which is essentially useless. There is also a small change of a nuclear reactor having a meltdown, resulting in the lives of thousands of people being put at risk.