Environmental Science Notes

Environmental Science

The Atmosphere

• The atmosphere consists of layers of gases surrounding the Earth.
• Troposphere:
  • Extends 17km (11 miles), 8km (5 miles) above the poles.
  • Contains 78% Nitrogen and 21% Oxygen.
• Stratosphere:
  • Extends 17km - 48km (11 - 30 miles).
  • High ozone concentration.
  • Stops about 95% of UV radiation.
• Mesosphere:
  • Extends 50km - 85km (31 - 53 miles).
  • Temperature drops with altitude.
  • It is the third layer of the atmosphere.

Earth's Sections

• Biosphere: Zone where life is found (extends 12 miles high).
  • Contains the atmosphere, hydrosphere, and lithosphere.
  • Also known as the ecosphere.
• Hydrosphere: Earth’s water supply.
  • Includes liquid water (oceans, lakes), frozen water (ice caps, permafrost), and water vapor.
• Lithosphere: Outer shell of the earth.
  • Composed of the crust and the rigid outermost part of the mantle.
  • Holds the tectonic plates.
  • 10km - 65km (6 - 40 miles) deep.
• Mantle:
  • Thick, solid zone around the earth’s core.
  • Mostly solid rock; contains a hot, half-melted zone called the asthenosphere.
• Core: Innermost part of the earth.
  • Inner core: solid due to pressure, though very hot.
  • Outer core: molten metal.

Plate Tectonics

• The Earth’s crust is made of many plates in constant motion due to rising magma and heat.
  • Transform Fault (Strike-slip fault): Plates move in opposite but parallel directions.
  • Divergent Plates: Plates move apart.
  • Convergent Plates: Plates are pushed together.

Water

• Surface Water: Water that does not penetrate the ground or evaporate.
• Ground Water: Water that sinks into the ground and remains in an aquifer, which are slowly renewed and susceptible to pollution.

Water Cycle (Hydrologic Cycle)

• Water evaporates into the atmosphere, condenses, and falls back to the ground.

• Becomes runoff, is used for power, nourishes plants, or is absorbed into aquifers.

• Plants emit water through pores, evaporating it again, while groundwater evaporates, restarting the cycle.
  Ocean Currents:

• Transfer heat throughout the world.

• If stopped, could cause ice ages in Europe.

Soil

• Governs food growth, water availability, and scenery.

Rock Cycle

• Constant recycling of rock matter based on time, pressure, and heat.

Soil Types

• O Horizon: Fresh or decaying organic material.
• A Horizon: Topsoil, holds organic matter, water, and nutrients.
• E Horizon: Leeching zone (not always present).
• B Horizon: Subsoil, accumulation of nutrients and some organic material.
• C Horizon: Parent material, broken down bedrock.
• Bedrock: Parent material to the C Horizon, with few nutrients.

Ecosystems

• Communities of different species interacting with each other and non-living factors.

Populations and Communities

• Population: A group of individual organisms of the same species in a particular area.
• Community: Many populations of all species living and interacting in a particular area during a particular time.

Niches

• Way of life for a species in an ecosystem.
• Includes physical, chemical, and biological conditions needed to live and reproduce.
• Useful for describing and classifying a species.

Species Interactions (Symbiosis)

• Parasitism: One species (parasite) benefits by feeding on another (host).
  • Parasite—Benefits, Host– Harmed
• Mutualism: Both species benefit.
  • Species1—Benefits, Species2—Benefits
• Commensalism: One species benefits, the other is neither harmed nor benefits.
  • Species1—Benefits, Species2—Neither
• Predation: One species preys on the other.
• Interspecific competition: Organisms of different species compete for the same resources, causing stress and competitive exclusion.

Energy Flow

• Energy is lost when transferred between trophic levels; it cannot be destroyed, but its quality changes.

Trophic Levels

• Producers: $Plants$ use organic and inorganic materials from the environment to grow.
• Primary Consumers: $Herbivores$ that consume producers.
• Secondary Consumers: $Carnivores$ that consume primary consumers.
• Tertiary Consumers: $Carnivores$ that consume secondary consumers.
  • Biomass: The dry weight of all organic matter contained in its organisms

Pyramid of Energy Flow

• Illustrates energy loss during trophic level transfers.
• Gross Primary Productivity: Rate at which producers change solar energy into chemical energy for biomass.
  • Food Chain: A list of organisms that eat the organism that precedes it on the chain. Each member of a food chain is usually on a different trophic level. It is a good display of how energy is transferred through various animals.
  • Net Primary Productivity: $Rate at which biomass is stored (GPP) - Rate at which chemical energy stored as biomass is used.$
• Food Web: A complex network of interconnected food chains with various organisms at different trophic levels.

Biodiversity

• Variety of species, variability, ecosystems, and functions needed for living.

Types of Biodiversity

• Genetic Diversity: Differences in genetic makeup within a species.
• Species Diversity: Variety of species in different habitats.
• Ecological Diversity: Number of different forests, deserts, grasslands, streams, lakes, oceans, coral reefs, wetlands, and other biological communities.
• Functional Diversity: Chemical or biological functions (energy flow, matter recycling) needed for survival. Loss of habitat is a major risk, causing extinctions; easy travel spreads species, reducing genetic biodiversity.

Natural Selection

• Process where individuals with genetically based traits have increased survival and reproduction.

Necessary Conditions

• Variability: Variety of traits must be available in the population.
• Heritable: Traits must be passed down from generation to generation.
• Differential Reproduction: Traits must increase the ability to reproduce.

Peppered Moth

• Example of natural selection; moth camouflaged into two different appearances based on lichen presence on trees.
• Galapagos Finches: Also known as Darwin’s Finches. They are found on the Galapagos Islands, and they have evolved drastically. They difference that they have encountered are the shapes of their beaks. Depending on what type of food and flower they are around, the finches have different types of beaks to allow them to reach into the stem of the flower they eat from.

Ecological Succession

• Gradual change in species composition of an area.

  • Primary Succession: First life moving into lifeless ground (pioneer species).
  • Secondary Succession: When some life is present on the ground. Larger plants begin to move into the area, these plants are slower growing, but have more resistance.
    Climate Change

• See global warming (Global Change)
  Carbon Cycle:

• Based on $CO_2$ in the atmosphere; carbon cycles from living things into the earth or ocean, transforming into fossil fuels that release carbon back when burnt.
  Nitrogen Cycle:

• The nitrogen cycle is broken down into many steps.

  • Nitrogen Fixation: Bacteria convert $N_2$ gas into ammonia for plants.
  • Nitrification: Ammonia converted to nitrite ions (toxic) and nitrates (taken up by plants).
  • Assimilation: Plant roots take up ammonia and nitrate ions to make nitrogen-containing organic molecules like DNA, amino acids, and proteins.
  • Ammonification: Bacteria converts the organic matter that contains nitrogen into simpler compounds of ammonia and salts containing ammonia ions.
  • Denitrification: Bacteria converts the nitrogen and nitrogen containing salts into nitrite and nitrate ions, and then into nitrogen gas and nitrous oxide gas.

Population

• Earth’s human population is growing rapidly, predicted to double in fifty years, causing concerns about living space and food production.

Age Structure Diagrams

• Show population proportion by sex and age level.

Growth Patterns

• Rapid Growth: High percentage of newborns.
  • Exponential increase, seen in Guatemala, Nigeria, and Saudi Arabia.
• Slow Growth: Youngest percentage is the highest, but not by very much.
  • Spread out how a slowly growing country’s population should. The highest percentage is the youngest, but not by very much. This type of growth is happening in the United States, Australia, and Canada.
• Zero Growth: Nearly equal percentage throughout the population.
  • equally spread out through the whole population. This growth is occurring in Spain, Austria, and Greece.
• Negative Growth: Lower percentage of young than old.
  • Shows a lower percentage of the population in the young than in the old. This is a very bad sign for countries because their future in uncertain. Some of these countries are German, Bulgaria, and Sweden.

Population Dynamics

• Biotic Potential: A population’s capacity for growth. The maximum rate of growth if there are no limitations on the population.
• Environmental Resistance: All factors limiting population growth.
• Carrying Capacity: Biotic potential combined with environmental resistance; number of individuals that can live in an area.
• Isle Royal National Park: Closed park to dogs in order keep the death variables low. There are usually 25 wolves, and 1000 moose, but the numbers change every year. This is used to study how the carrying capacity changes based on the amount of a certain species.

Easter Island

• Initially plentiful resources and 100 humans; later, 3000 inhabitants and few resources, leading to population collapse due to disease, cannibalism, and invasive species.

Cultural Effects

• The One Child policy in China is an attempt to slow the birth rate so that it does not become too much higher than the death rate.
• Heritage drives preference for boys, resulting in abortions and abandonment of girls.

Economic Effects

• Rapid population growth increases real estate costs.
• If carrying capacity is surpassed, supply will be high, demand low, causing bankruptcies.

Human Population Issues

• Population is growing exponentially due to advancements in human rights, medical technology, and standard of living.

Doubling Time

• The equation for calculating the time for a population to double is dividing 70 by the percentage growth rate. The growth rate of the world is currently approximately 1.14%. This means that the doubling time of the population of the world is 61.4 years.
• The world's growth rate was highest in the 1960s, when it was 2% and the doubling time was ≈ 35 years.
• Undeveloped nations suffer most from overpopulation due to insufficient medical care.

Land and Water Use

• Food and water are necessities; their protection is vital.
  Humans depend on three systems:

• Croplands

• Rangelands

• Oceanic Fisheries

Agriculture

• Industrialized Agriculture (High-input Agriculture):

  • Needs large amounts of fossil fuels, water, commercial fertilizers, and pesticides to produce large quantities of a single crop (monoculture).
  • Used on 25% of cropland (mostly in developed countries)
  • Plantation Agriculture: Intensive agriculture in developing tropical countries growing cash crops on large monoculture plantations for developed countries.
  • Livestock: Mass-produced, not cared for individually.

• Traditional Agriculture:

  • Used by 2.7 billion people (44%) in developing countries, providing 20% of the world’s food supply.

• Traditional Substance Agriculture:

  • Uses mostly human labor and draft animals to make only enough crops that are necessary for the farmer and his family to survive.

• Very low amount of energy are needed to grow the food, but the outcome is also very small

• Profits are very low if there are any.

• Traditional Intensive Agriculture

  • Farmers increase their input of human and animal labor, fertilizer, and water
  • Higher yield per area of cultivated land
  • Able to produce enough to feed family, and some to sell for a profit

• Sustainable Agriculture

  • Being pushed by environmentalists so that this is the only type of farming that is done.
  • The amount of land available is only going to decrease with a growing population
  • It may also be limited by a lack of water for irrigation, lower genetic diversity, and existing cropland degradation.
  • Produces equivalent yields with lower carbon dioxide emissions
  • Uses about 50% less energy than conventional farming
  • Improves soil fertility
  • Provides more habitat for wild plant and animal species
  • Generally more profitable for the farmer than high-input farming
    Preventing Soil Erosion:

• Conventional-tillage farming: Soil plow and break up the soil to make a planting surface. Very vulnerable to erosion, and much is washed away in the winter

• Conservation-tillage farming: the soil is disturbed as little as possible to help prevent soil erosion. In minimum – tillage farming, special machines loosen the subsurface without turning over the soil.

• Terracing: Cutting flat tiers into a hillside for planting crops row by row.

• Contour farming: Planting crops along contours of a gentle hill, slowing water flow and reducing erosion

• Establishing windbreaks (shelter belts): Trees that reduce wind erosion, retain soil moisture, provide wood, and habitat.

• Gully Reclamation: Restoring bare land by planting shrubs, vines, and trees, building small dams to collect silt, replacing soil, and building channels to divert water.
  Old Growth Forests Uncut forests or regenerated forests that have gone undisturbed for at least several hundred years, providing many ecological niches.

• Secondary-Growth Forests: Result from secondary succession after tree removal.

• Tree Plantations: Tracks of same-aged trees of one species replanted and cut on cycles, occupying 5% of tree cover.

Forest Fires

• Can clear forest floor material and control growth.
• Surface Fires: Burn brush on the ground, killing seedlings but not larger trees; remove flammable buildup, release minerals, increase nitrogen-fixing bacteria, stimulate seed germination, and control pathogens.
• Crown Fires: Extremely hot fires that burn entire trees; occur in forests with flammable buildup, destroying vegetation, killing wildlife, and increasing soil erosion.

Rangelands

• $40$ of earth's non-ice land; supplies land and food for grazing animals (3.3 billion cattle graze on 42% of world's rangeland).
• Over Grazing: Occurs when grazing animals exceed carrying capacity, lowering net primary productivity, increasing erosion, and compacting soil.
• Desertification: Productivity falls by 10% or more due to climate change or human activities.

Desertification Levels

• Moderate Desertification: 10-25% drop in productivity.
• Severe Desertification: 25-50% drop in productivity.
• Very Severe Desertification: 50% or more drop in productivity.

Rangeland Management

• Control livestock numbers, types, and distribution.

• Implement deferred grazing and rangeland restoration.

• Controlling animals is best but not profitable in short term.
  Pollution

• Defined as an “undesirable change in the physical, chemical, or biological characteristics of air, water, soil, or food that can adversely affect the health, survival, or activities of humans or other living organisms.

Air Pollution

• Common type of pollution due to constant breathing of air.

Sources

• Burning Fuel: Combustion-fired power plants, Agriculture and forest management, motor vehicles, marine vessels and related port air pollution. Also Burning wood, fireplaces, stoves, furnaces, and incinerators,
• Other Human Activities: Oil refining, chemicals from farming, dust from farming, paint fumes, aerosol sprays, waste deposition in landfills, and military uses like weapons and gasses.
• Natural Sources: Dust from erosion, methane from animal digestion, radon gas, smoke and carbon monoxide from wildfires, and volcanic activity.

Pollutants

• Primary Pollutants: Emitted directly into the troposphere in harmful form (carbon dioxide, carbon monoxide, sulfur dioxide, nitric oxide, nitrogen dioxides)
• Secondary Pollutants: Formed from primary pollutants reacting with air (sulfur trioxide, ozone, dihydrodioxide).

Urban Land Development

• Urban Growth: The rate of increase of urban populations
  • Natural Increase: More births than deaths
  • Immigration: People moving out of rural areas and being pushed into urban areas by factors such as poverty, lack of land, and declining agricultural jobs available in the rural land.
    • The proportion of people living in urban areas is increasing.
    • Everyday 16,000 move to an urban city. Also, the number of large cities has increased rapidly in the last 100 years.
    • Problems that arise with large cities are
      • Severe air pollution
      • High Unemployment
      • Deafening noise
      • High crime rate

Mining Types

• Open Pit Mining: Machines dig holes to remove ores, sand, gravel, Limestone and marble
• Dredging: Underwater mineral deposits are pulled up with chain buckets and drag lines.
• Area Strip Mining: Removing trees and brush, then digging a hole to remove the mineral deposit. The hole is then filled with dirt, and a new hole is dug parallel to the original. This process is repeated over the entire site.
• Contour Strip Mining: Cutting terraces into hillsides, removing minerals, and dumping soil from the new hole into the old one.
• Mountaintop Removal: Removing mountain tops with explosives and heavy machinery to expose coal seams.

Fishing

• Areas of specific aquatic animals that are suitable for commercial resale in a given ocean or inland body of water.
• Industrial fishing fleets use GPS, sonar, large nets, spotter planes, and factory ships.
  • This gives the large companies a huge advantage over the smaller companies that cannot afford the equipment and the services necessary to compete.

Fishing Types

• Purse-seine fishing: Catches surface dwelling fish
• Longlining: Fishing ships put out lines up to 80 miles long with thousands of baited hooks to catch open-ocean species like swordfish, tuna, and sharks
• Drift-net fishing: Fish are caught in huge drift nets.

Energy

• Capacity to do work by mechanical, physical, chemical, or electrical tasks or to cause heat transfer.

Types of Energy

• Kinetic Energy: Energy of matter with mass or velocity (wind, flowing streams, heat, electricity).
• Potential Energy: Stored energy that could be used (rock in hand, dynamite, water behind dam, chemical energy in gasoline, nuclear energy).

Conservation

• It is very important because not all types of commercial energy are renewable.

Impacts of Pollution

• Human
  • Bad air quality can kill many organisms
  • Ozone can cause respiratory disease, cardiovascular disease, throat inflammation , chest pain, and congestion
  • Water pollution causes about 14,000 deaths a day usually due to contamination of drinking water
  • Oil spills can cause skin irritations and rashes
  • Noise pollution causes hearing loss, high blood pressure, stress, and sleep disturbance
• Environmental
  • Sulfur dioxide and nitrogen causes acid rain, which reduces the pH of the soil and water
  • Soil can become infertile, and unusable by plants
  • Smog can reduce sunlight that reaches the plants, and restrict their ability to photosynthesize

Hazardous Chemicals

• Hazardous chemicals in the environment can cause many deaths to organisms. Also, nuclear waste is extremely hazardous, and it is difficult for us to find a place to store it.
• Biomagnification: Causes many deaths in animals that are high in the food chain

Economic Impacts

• Prevention v. clean up
• Smog
  Smog consists mostly of sulfur dioxide, suspended solid particles, and suspended droplets of sulfuric acid. It is created mainly through the burning of fossil fuels such as oil and coal. When two sulfur dioxide molecules react with one oxygen molecule, sulfur trioxide is formed that then reacts with water vapor to form sulfuric acid.
  2 SO2 (g) + O2 (g) -> 2SO3 (g) $SO</em>3 (g) + H<em>2O (l) -> H</em>2SO_4 (aq)$

Acid Deposition

• Pollutants (nitric oxide, sulfur dioxide) react with water vapor to create nitric acid and sulfuric acid, falling as acid rain and snow.
• If the water or soil is high in limestone or other high pH materials, then the acid rain will be neutralized, and the effects will be minimal. If the water or the soil has nothing to buffer the acidity, they will also become acidic, and could cause harm to many organisms.

Noise Pollution

• Any unwanted disturbing, or harmful sound that impairs or interferes with hearing, causes stress, hampers concentration and work efficiency, or causes accidents.

Reducing Noise Pollution

• Modifying activities and devices to produce less noise, shielding noisy devices, shielding workers, moving noisy operations, and using anti-noise.

Water Pollution

• Dangerous and easily spread; hard to detect.

Pollution Sources

• Industrial discharge of chemical wastes, discharge of poorly treated sewage, surface runoff containing pesticides or fertilizers, surface runoff containing petroleum products, acid rain, eutrophication due to runoff, and underground storage tanks leaking

Contaminants

• Contaminants that might be included in water pollution are insecticides, herbicides, bacteria (sewage), pathogens, heavy metals, acidity, chemical waste, fertilizers (nitrates and phosphates), and silt.

Groundwater

• Important to agriculture, but easily contaminated and difficult to check.

Solid Waste

• Unwanted or discarded material that is not a liquid or a gas. The United States composes only 4.7 % of the world’s population , but produces 33% of the world’s solid was

Groundwater

• Groundwater is very important to our agriculture system and to our nation, but it is also easier to contaminate. Because the water is located underground, it is very difficult for us to determine if the groundwater is contaminated with any pollutants or not. This can be very dangerous to many organisms if the water is not checked periodically to ensure the safety of the water.

Global Change

• Question: Are we causing the changes, or are they natural changes of the climates?

Ozone Layer

• Layer of $O_3$ molecules blocking UV radiation.

Chemicals that Damage it:

• $Chlorofluorocarbons$ (CFCs): used in coolants and aerosols.

• Halons: used in fire extinguishers.

• Problems: These cause human health problems like skin cancer, cataracts, and reduced immune function and other ecological problems like crop damage and global warming.
  Global Warming

• Earth has warmed 0.5 degrees in the past 100 years.

• Theory: Increased $CO_2$ production causes greenhouse effect and warming.

• Fear: Melting of polar ice caps raises sea levels, flooding coastal land.

Hydropower

Hydropower Pros

• Moderate to high net energy
• High efficiency (80%)
• Low-cost electricity
• Long life span
• No $CO_2$ emissions during operation
• May provide flood control below dam
• Provides water for year-round irrigation of cropland
• Reservoir is useful for fishing and recreation

Hydropower Cons

• High construction costs
• High environmental impact
• Floods natural area
• Converts land to lake habitat
• Danger of collapse
• Decreases fish harvest below dam
• High $CO_2$ emissions from biomass decay in shallow tropical resevoirs

Nuclear Energy

Nuclear Pros

• Large fuel supply
• Low environmental impact
• Emits 1/6 the $CO_2$ as coal
• Moderate land disruption and water pollution
• Moderate land use
• Low risk of accidents because of multiple safety systems

Nuclear Cons

• High cost (even with subsidies)
• Low net energy yield
• High environmental impacts with accidents
• Catastrophic events can occur
• No acceptable solution for long-term storage of radioactive wastes and decommissioning worn-out plants
• Spreads knowledge and technology for building nuclear weapons

Energy Free Response Question

• Question The city of Mt. Laurel has 5,000 homes. The electricity for these homes is produced by a small coal-powered electrical plant. The average household in Mt. Laurel uses 10,000 kilowatt hours per year. The capacity of the power plant is 13 megawatts.
• A.) At the current use of household electricity, how much does Mt. Laurel use each year?
• B.) If the power plant runs at full power for one year (8,750 hours) how much energy will be produced?
• C.) How many more people could move to Mt. Laurel before needing to upgrade the power plant?
• D.) What are two pros and cons to using fossil fuels opposed renewable energy?

Grading

• Grading A.) (2 points) One point for correct setup One point for correct answer 5,000 homes * 12,000 kW hours / year = 60,000,000 kWh / year
• B.) (2 points) One point for correct setup One point for correct answer 13 MW = 13,000 kW 13,000 kW * 8,750 hrs / year = 113,750,000 kWh / year
• C.) (2 points) One point for correct setup One point for correct answer
  • 113,750,000 kWh / year potential - 60,000,000 kWh / year already used = 53,750,000 kWh / year potential leftover
  • 53,750,000 kWh / year / 10,000 kWh / home = 5375 more people could move into Mt. Laurel
• D.) (4 points) Two points for benefits Two points for cons

Stratospheric Ozone

Pros

• Low cost
• Plentiful (Coal)
• Compact generators

Cons

• Most of the plants are designed to handle fossil fuels, not renewable resources
• Not sustainable
• Produces a lot of $CO_2$
• Mining is very destructive
• Large quantities of ash
• Oil spills and other types of pollution