Atmosphere

• Definition: A layer of gas that envelopes the planet and is held in place by the Earth’s gravity

• Gas Composition of the Atmosphere

  • 78% Nitrogen (N₂)

  • 21% Oxygen (O₂)

  • ~1% Water Vapor

  • Trace Amounts of Argon (Ar), Carbon Dioxide (CO₂), and Aerosols

• Layers of the Atmosphere

  • General Characteristics of Atmosphere Layers

    • Differentiator: Changes in Temperature, Absorption Rate of Solar Energy

    • Range: Altitude and the Earth’s Spherical Shape

  • Troposphere

    • The lowest layer of our atmosphere, where life and weather occurrences occur

    • From ground level to at least 10 kilometers above sea level

    • ↑ Altitude → ↓ Air Pressure & ↓ Temperature

  • Stratosphere

    • From 10 kilometers to 50 kilometers above sea level

    • Presence of the ozone layer and jet streams

    • ↑ Altitude → ↑ Temperature

  • Mesosphere

    • From 50 kilometers to 85 kilometers above sea level

    • Region where most meteors start to burn

    • ↑ Altitude → ↓ Air Pressure & ↓ Temperature

  • Ionosphere

    • Region within the Mesosphere and the Thermosphere

    • Solar Radiation knocks electrons loose, charging them into ions

  • Thermosphere

    • One of the topmost layers of our atmosphere

    • From 85 kilometers to 500–1000 kilometers above sea level

    • Region where satellites are present

    • ↑ Altitude → ↓ Air Pressure & ↑ “Temperature” (“Cold”)

  • Exosphere

    • One of the topmost layers of our atmosphere, the “final frontier”

    • From 100k to 190k kilometers above sea level

    • ↑ Altitude → ↓ Air Pressure

• Air Pollutants

  • Definition: A mix of particles and gases which, upon reaching harmful concentrations, increase risk of disease and heighten temperatures

  • Sources of Air Pollution

    • Natural Air Pollutants

      • Sources: Dust blown by wind, pollutants from wildfires and volcanic eruptions, and volatile organic chemicals released by some plants

      • Primarily spread out throughout the globe or removed by natural processes (chemical cycles, precipitation, gravity)

    • Artificial Air Pollutants

      • Sources:

        • Stationary Sources: Burning of Fossil Fuels, Industrial Plants

        • Mobile Sources: Gasoline/Diesel Fuel in Cars

      • Concentrated in industrial and/or urban areas

  • Primary and Secondary Pollutants

    • Primary Pollutants: Harmful chemicals emitted directly into the air from natural processes and human activities

    • Secondary Pollutants: Primary pollutants reacting with one another or with the basic components of air to form new harmful chemicals

  • Major Air Pollutants

    • Carbon Oxides (CO/₂)

      • Colorless, odorless, and potentially toxic gases contributing to climate change

      • Sources: Motor vehicle exhaust, clearing and burning of forests and grasslands, inefficient cooking practices, burning of fossil fuels, etc.

    • Nitrogen Oxides (NO/₂), Nitrous Oxide (N₂O) & Nitric Acid (HNO₃)

      • Chemicals responsible for harmful acid deposition and irritation of respiratory + integumentary system

      • Sources: coal-burning power plants, high-temperature automobiles, lightning & select bacteria (nitrogen cycle), fertilizers and animal wastes

      • Creates photochemical smog, a chemical mixture formed due to sunlight in cities with heavy traffic

    • Sulfur Dioxide (SO₂) and Sulfuric Acid (H₂SO₄)

      • Components of acid rain, they aggravate physical ailments, damage flora and fauna, and corrode materials

      • Sources: one-third sulfur cycle, two-thirds due to combustion of sulfuric containing materials and processes

    • Suspended Particulate Matter (SPM)

      • Catch-all term for toxic solid particles and liquid droplets small and light enough to remain suspended in the air for long periods

      • Sources: 62% Natural (dust, wildfires, and sea salt), 38% Artificial (plowed fields, road construction, unpaved roads, tobacco smoke, coal-burning electric power and industrial plants, and motor vehicles)

    • Ozone (O₃)

      • A colorless and highly reactive gas serving as a component for photochemical smog

      • Aggravates respiratory and circulatory disease, damages plants, rubbers, tires, paints

    • Volatile Organic Compounds

      • Organic compounds existing as gases in the atmosphere, primarily hydrocarbons

      • Sources: one-third from natural sources (plants, wetlands, and termites), two-thirds from artificial sources (rice paddies, landfills, and oil and natural gas wells)

      • Mostly serves as components for various industrial products

• Global Warming & Climate Change

  

Hydrosphere

• Composition of the Hydrosphere

  • 71% of the Earth’s surface is covered in water

  • 2.5% freshwater

  • 1% readily available, consumable freshwater

• Water/Hydrologic Cycle

  

  • Surface water and groundwater are highly connected

  • The movement of water in the sea, in the air, and on land, which is driven by solar energy and gravity

• Main Water Resources

  • Groundwater

    

    • Key Characteristics

      • The most important source of water

      • It fills the spaces between soil particles and fractured rock beneath the earth’s surface

    • Parts of Groundwater

      • Zone of Saturation (Zone of soil and rock saturated with water)

      • Water Table (Top of the groundwater)

      • Aquifers

        • Unconfined Aquifer (water seeps from the ground surface directly above the aquifer)

        • Confined Aquifer (layers of impermeable material are both above and below the aquifer)

  • Surface Water (Rivers and Watershed)

    

    • Watersheds or drainage basins are an area of land that contributes water to a particular stream of river

    • The boundary of a watershed is called a drainage divide

• Surface and Groundwater Pollution

  • Defining Water Pollution

    • One of the main threats to our water resources

    • Can be measured by biological (fecal coliform), chemical (N-P-K), or physical (sedimentation) criteria

  • Types of Water Pollutants/Sources

    • Point Sources

      • Pollutants are discharged at specific locations, such as drain pipes, ditches, or sewer lines into bodies of water

      • Traditionally easy to identify, monitor, and regulate (dependent on the economic resources of a country)

      • Examples: Factories, sewage treatment plants, underground mines, and oil tankers

    • Non-Point Sources

      • Pollutants are scattered and diffuse and cannot be traced to any single site of discharge

      • Significantly harder to identify, monitor, and regulate

      • Examples: Runoff of chemicals and sediments into surface water from cropland, livestock feedlots, logged forests, urban streets, lawns, and golf courses

  • Types of Water Pollution

    • Lotic/Standing Water Pollution (Difficult to dilute and discharge pollutants due to weak flow and stratified layers of water)

      

    • Lentic/Running Water Pollution (Can rapidly recover from pollutants due to dilution, biodegradation, and bacterial presence breaking down wastes)

      

    • Coastal/Oceanic Water Pollution (Most affected from the input of pollutants into water systems)

      

  • Sources of Water Pollution

    • Oxygen-Demanding Waste

      • Dead organic matter decayed and consumed by aerobic bacteria

      • Evaluated by Biochemical Oxygen Demand (BOD), ↑ BOD = ↑ Organic Matter

      • Sources: Natural Sources (Fallen Leaves), Agriculture, Urban Sewage

    • Pathogenic Organisms

      • Pathogenic microbes or microorganisms

      • Evaluated by level of human fecal coliform bacteria in water systems

      • Examples: Cholera, typhoid infections, hepatitis, dysentery, and other waterborne diseases

    • Nutrients

      • Nutrients released by human intervention, particularly phosphorus and nitrogen

      • May cause cultural eutrophication

      • Material Sources: fertilizers, detergents, and the products of sewage treatment plants

      • Systemic Sources: Agricultural Areas, Urban Areas

    • Oil

      • Oil discharged into surface water

      • Source: Oil-Tanker Accidents

    • Toxic Substances (heavy metals, synthetic organic chemicals, etc.)

    • Harmful Algal Bloom (production of algae-produced toxins via phytoplankton)

    • Miscellaneous (Sediments, Thermal Pollution, etc.)

  • Groundwater Pollution

    

    • Groundwater flows very slowly–usually less than 0.3 meters per day

    • Non-degradable wastes (toxic lead, arsenic, and fluoride) can take thousands of years to decompose and be removed from the system, considering them permanent pollutants

    • Solutions:

      • Extraction Wells: Pumping out contaminated water and treatment by filtration, oxidation, air stripping (volatilization of contaminant in an air column), or biological processes

      • Vapor Extraction: Use of vapor-extraction well and then treatment

      • Bioremediation: Injection of nutrients and oxygen to encourage growth of organisms that degrade the contaminant in the groundwater

      • Permeable Treatment Bed: Use of contact treatment as contaminated water plume moves through a treatment bed in the path of groundwater movement; neutralization of the contaminant by chemical, physical, or biological processes

Geosphere

• General Characteristics

  • Rocks and minerals on Earth, from the molten rock and heavy metals in the deep interior of the planet to the sand on beaches and peaks of mountains

  • The abiotic parts of soils and the skeletons of animals that may become fossilized over geological time

• Rock Cycle

  

  • Processes such as metamorphism, melting and solidification, weathering, erosion, deposition, and burial responsible for a constant recycling of rocks on Earth

  • Primary Agent of Change: Earth’s Tectonic Plate Movements

  • Types of Rocks

    • Sedimentary Rocks (formed via weathering and transport of existing rocks, and then deposition, cementation, and compaction into a sedimentary rock)

    • Igneous Rocks (formed by the cooling and crystallization of molten rock)

    • Metamorphic Rocks (formed when heat or pressure are applied to other rocks)

• Soil Resources: Formation and Conservation Strategies

  • Defining Soil

    • Soil Science Definition: Solid Earth material that has been altered by physical, chemical, and biological processes such that it can support rooted plant life

    • Geology Definition: Products of disintegration or decomposition of rocks

    • Soil as an Ecosystem: It comprises countless species that create a dynamic and complex ecosystem and is among the most precious resources to humans.

    • SOIL IS A NON-RENEWABLE RESOURCE. In theory, soil regeneration is possible for polluted or unhealthy soils. However, regeneration takes so much more time compared to pollution that soils should not be considered as a renewable resource.

  • Soil Characteristics

    • Soil Texture

      • Dependent on the relative proportions of sand-, silt-, and clay-sized particles

      • Primarily identified by estimation refined via laboratory experiments, may be guessed via the “feel” of the particle

      • Types of Soil Particles

        • Clay

          • Diameter of less than 0.004 mm (0.0002 in.)

          • Plate-like structure, cannot be dusted off if immersed in water, feels cohesive

          • Holds water and nutrients effectively due to diameter and structure

        • Silt

          • Diameters ranging from 0.004 to 0.063 mm (0.0002 to 0.003 in.)

          • Silt feels like baking flour, can be dusted off if immersed in water

        • Sand

          • 0.063 to 2.0 mm (0.003 to 0.08 in.) in Diameter

          • Gritty feel, chunky structure

    • Soil Color (An indicator of organic matter content, drainage and aeration)

      • Black: High in organic matter (4 percent or more)

      • Brown: Good organic matter content and well drained.

      • Red: Low in organic matter, well drained. Red color is due to the presence of iron (often ferric oxide, Fe2O3).

      • Grey: Low in organic matter, poorly drained. Gray color is due to an excess of water and poor aeration. Gray color is due to the presence of iron (often ferrous oxide, FeO).

      • Yellow: Low in organic matter, well drained.

      • Mottling effects in subsoil: Indicates both well and poorly drained conditions during the year due to fluctuations in water table.

  • Soil Nutrients and Plant Nutrition (Macronutrients)

    • Non-Mineral Elements (Carbon [C], Hydrogen [H], Oxygen [O])

    • Primary Nutrients (Nitrogen [N], Phosphorus [P], Potassium [K])

      • Nitrogen

        • Building block of plant proteins, an integral part of chlorophyll and is a component of amino acids, nucleic acids and coenzymes

        • Taken up by plants as nitrate (NO3-) and ammonium (NH4+) ions

      • Phosphorus

        • Used to form the nucleic acids DNA and RNA and to store and transfer energy

        • Promotes early plant growth and root formation through its role in the division and organization of cells

        • Essential to flowering and fruiting and to the transfer of hereditary traits

      • Potassium

        • Necessary to plants for translocation of sugars and for starch formation

        • Important for efficient use of water through its role in opening and closing small apertures (stomata) on the surface of leaves

    • Secondary Nutrients (Calcium [Ca], Magnesium [Mg], Sulfur [S])

  • Soil in Agriculture

    • General Characteristics

      • The Philippines is an agricultural country with a land area of 30 million hectares, 47% of which is agricultural land

      • Prime agricultural lands are located around the main urban and high-population-density areas

      • ~27% of total employment, more than half the dependent population, and about 9% of GDP (2016): account for much of the poor & vulnerable

    • Erosion Mitigation Measures

      • Contour Plowing

        • Plowing with the natural topography of the land

        • Furrows are plowed perpendicular to the slope to reduce erosion

      • Terracing Slopes

        • Produces flat areas for farming

        • Retaining walls of stone or other materials are used to form terraces and stabilize the slope

      • No-Till Agriculture

        • Eliminates plowing altogether, greatly reducing soil erosion

        • Tilling involves turning over the first 6-10 inches of soil before planting new crops

      • Planting of Multiple Crops

        • The forest trees are cut in small patches of land, and some smaller trees and plants are left in place

        • Several crops are planted among the remaining natural vegetation

        • This approach works if human population on the land is low

• Climate Change and Unsustainable Land Use Practices

  • Effects of Climate Change

    • Agriculture is the most weather-dependent sector in the Philippines

    • More Rainfall → Land inundation and erosion; damage to crops, fisheries, livestock; Losses in agricultural inputs (seeds, fertilizers)

    • More Cyclone → Direct loss to crops, fisheries, and livestock; soil becomes infertile; scarcity of freshwater (irrigation)

    • Humid/Warm Climate → Rise in crop pests and diseases; animal diseases

    • Lower Rainfall → Scarcity of water irrigation; soil and nutrient deficiency

  • Effects of Unsustainable Land Use Practice (Land Degradation)

    • Reduction or loss of the biological or economic productivity and complexity of rainfed cropland, irrigated cropland, or range, pasture, forest, and woodlands

    • Soil erosion caused by wind and/or water

    • Deterioration of the physical, chemical, and biological or economic properties of soil

    • Long-term loss of natural vegetation