Environmental Science Lecture Notes

Vocabulary-style flashcards covering the core concepts of environmental science, including energy types, thermodynamics, population dynamics, pollution, and sustainability.

Ionizing radiation

Radiation with enough energy to knock electrons from atoms forming ions, capable of causing cancer (ex: gamma, X-rays, UV).

High Quality Energy

Organized and concentrated energy that can perform useful work (ex: fossil fuel and nuclear).

Low Quality Energy

Disorganized and dispersed energy (ex: heat in the ocean or air, wind, solar).

First Law of Thermodynamics

Energy is neither created nor destroyed, but may be converted from one form to another.

Second Law of Thermodynamics

When energy is changed from one form to another, some useful energy is always degraded into lower quality energy, usually heat.

Natural radioactive decay

Unstable radioisotopes decay releasing gamma rays, alpha, and beta particles.

Half life

The time it takes for $\frac{1}{2}$ the mass of a radioisotope to decay.

Safe storage level estimation

Radioactive isotopes must be stored for approximately $10$ half-lives before they decay to a safe level.

Nuclear Fission

The splitting of nuclei of isotopes when struck by neutrons.

Nuclear Fusion

The process where two isotopes of light elements ($H$) are forced together at high temperatures until they fuse to form a heavier nucleus.

Ore

A rock that contains a large enough concentration of a mineral to make it profitable to mine.

Organic fertilizer

Fertilizer that is slow acting and long lasting because the organic remains need time to be decomposed.

Best solution to Energy shortage

Conservation and increasing efficiency.

Surface mining

A cheaper method that can remove more mineral and is less hazardous to workers.

Humus

Organic, dark material remaining after decomposition by microorganisms.

Leaching

Removal of dissolved materials from soil by water moving downwards.

Illuviation

The deposit of leached material in lower soil layers (B).

Loam

Perfect agricultural soil containing equal portions of sand, silt, and clay.

Conservation vs Preservation

Conservation allows responsible use of resources; Preservation sets aside areas and protects them from human activities.

Hydrologic cycle parts

Evaporation, transpiration, runoff, condensation, precipitation, and infiltration.

Aquifer

Any water bearing layer in the ground.

Cone of depression

The lowering of the water table around a pumping well.

Salt water intrusion

The movement of saltwater into the aquifer caused by overpumping of groundwater near the coast.

ENSO

El Niño Southern Oscillation, the see-sawing of air pressure over the South Pacific.

El Niño year characteristics

Trade winds weaken and warm water sloshes back toward South America.

Non-El Niño year characteristics

Easterly trade winds and ocean currents pool warm water in the western Pacific, allowing upwelling of nutrient rich water off the West coast of South America.

Effects of El Niño

Upwelling decreases disrupting food chains, Northern US has mild winters, SW US has increased rainfall, and fewer Atlantic Hurricanes.

Nitrogen fixing

The conversion of atmospheric $N$ into ammonia by bacteria because plants cannot use atmospheric $N$ directly.

Ammonification

Decomposers converting organic waste into ammonia.

Nitrification

The conversion of ammonia into nitrate ions ($NO_3^-$).

Assimilation

Inorganic $N$ is converted into organic molecules such as DNA, amino acids, and proteins.

Denitrification

Bacteria converting ammonia back into nitrogen ($N$).

Phosphorus circulation

It does not circulate as easily as Nitrogen because it does not exist as a gas and is released through the weathering of phosphate rocks.

Sustainability

Meeting humanity's current needs without compromising the ability of future generations to meet their own needs.

Causes of excess phosphorus in aquatic ecosystems

Runoff of animal wastes, fertilizer, and discharge of sewage.

Photosynthesis

Plants converting atmospheric carbon ($CO_2$) into complex carbohydrates like glucose ($C_6H_{12}O_6$).

Aerobic respiration

Producers, consumers, and decomposers consume oxygen to break down organic compounds and convert carbon back into $CO_2$.

Largest reservoirs of Carbon

Carbonate rocks (first) and oceans (second).

Biotic vs Abiotic

Biotic refers to living components; Abiotic refers to nonliving components of an ecosystem.

Producer (Autotroph)

Photosynthetic life.

Fecal coliform

An indicator of sewage contamination.

10% Rule in food webs

Only $10\%$ of usable energy is transferred because energy is lost as heat, not all biomass is digested, and energy is spent catching prey.

Chlorine (Pros/Cons)

Good for water disinfection; Bad because it forms trihalomethanes.

Primary vs Secondary succession

Primary is development in lifeless areas (lava); Secondary is progress where soil remains (clear cut forest).

Cogeneration

Using waste heat to generate electricity.

Mutualism

A symbiotic relationship where both partners benefit.

Commensalism

A symbiotic relationship where one partner benefits and the other is unaffected.

Parasitism

A relationship where one partner obtains nutrients at the expense of the host.

Biome

A large terrestrial region with similar climate, soil, plants, and animals.

Carrying capacity

The number of individuals that can be sustained in a specific area.

R strategist vs K strategist

R strategists reproduce early with many unprotected offspring; K strategists reproduce late with few cared-for offspring.

Positive feedback

When a change triggers a response that intensifies the condition (e.g., Earth warms, snow melts, more heat is absorbed).

Natural selection

Organisms with favorable adaptations pass them on to subsequent generations.

Malthus

Theorized that human population cannot increase indefinitely, leading to war, famine, and disease.

Doubling time (Rule of 70)

$70$ divided by the percent growth rate.

Replacement level fertility

The number of children a couple must have to replace themselves ($2.1$ in developed, $2.7$ in developing countries).

World and US Population

World is almost $6.5$ billion; US is $290$ million.

Demographic stages: Preindustrial

High birth and death rates, slow growth, and high infant mortality.

Demographic stages: Transitional

Lower death rate due to better health care, leading to fast population growth.

Demographic stages: Industrial

Decline in birth rate, causing population growth to slow.

Demographic stages: Postindustrial

Both birth and death rates remain low.

Age structure shapes

Broad base (rapid growth), narrow base (negative growth), and uniform shape (zero growth).

Most populated countries

China (1st) and India (2nd).

Key factor in population growth

The low status of women.

Methods to decrease birth rate

Family planning, contraception, and economic rewards or penalties.

Earth's water distribution

$97.5\%$ seawater and $2.5\%$ freshwater.

Salinization

Evaporation in arid regions that leaves salts behind in the soil.

Water conservation methods

Drip/trickle irrigation in agriculture, recycling in industry, and gray water or low-flow fixtures at home.

Point vs Non-point sources

Point comes from a specific location (pipe); Non-point comes from over a broad area (runoff).

BOD (Biological Oxygen Demand)

The amount of dissolved oxygen needed by aerobic decomposers to break down organic materials.

Eutrophication

Rapid algal growth caused by an excess of Nitrogen and Phosphorus.

Hypoxia

Drop in dissolved oxygen ($DO$) caused by aerobic decomposers breaking down dead aquatic plants, making water unable to support life.

Minamata Disease

Mental impairments caused by mercury poisoning.

Primary air pollutants

Human or naturally produced pollutants like $CO, CO_2, SO_2, NO$, hydrocarbons, and particulates.

Negative feedback

When a change triggers a response that counteracts the condition (e.g., warmer earth causes more clouds, which reflect sunlight and cool it).

Particulate matter

From fossil fuels and exhaust; causes respiratory irritation and reduced visibility; reduced by filters or electrostatic precipitators.

Nitrogen Oxides (NOx)

From auto exhaust; leads to smog/ozone and acid formation ($NO + O_2 \rightarrow NO_2 + H_2O \rightarrow HNO_3$); reduced by catalytic converters.

Sulfur oxides (SOx)

From coal burning; causes acid deposition ($SO_2 + O_2 \rightarrow SO_3 + H_2O \rightarrow H_2SO_4$); reduced by scrubbers and low sulfur fuel.

Carbon oxides (CO and CO2)

$CO$ binds to hemoglobin reducing oxygen transport; $CO_2$ contributes to global warming.

Ozone (O3)

A secondary pollutant ($NO_2 + UV \rightarrow NO+O$; $O + O_2 \rightarrow O_3$); causes respiratory and plant damage.

Radon

Radioactive gas from Uranium decay; causes lung cancer; a specific problem in the Reading Prong.

Photochemical smog

Formed by chemical reactions involving sunlight, $NO$, VOCs, and $O$..

Acid deposition

Lowering of pH in surface waters caused by sulfuric and nitric acids.

Greenhouse gases

Gases like $H_2O, CO_2, O_3, CH_4$, and CFC's that trap outgoing infrared (heat) energy.

Global warming effects

Rising sea level via thermal expansion, extreme weather, droughts/famine, and extinctions.

Ozone depletion causes

CFC's, methyl chloroform, carbon tetrachloride, halon, and methyl bromide.

Ozone depletion effects

Increased UV exposure resulting in skin cancer, cataracts, and decreased plant growth.

Love Canal, NY

A site where buried chemicals caused cancer and birth defects in a community built over an old canal.

Municipal solid waste (MSW)

Mostly consists of paper, most of which is landfilled.

External costs

Harmful environmental side effects not reflected in the price of a product.

Sanitary landfill issues

Leachate (needs liners), methane gas (needs burning/collection), and garbage volume (needs compaction).

Incineration pros and cons

Pros: reduces waste volume by $90\%$; Cons: toxic emissions (dioxin) and heavy metal ash disposal.

Best waste management solution

Reducing the amount of waste at the source.

Keystone species

Species with a disproportionately important role in an ecosystem (ex: sea otter).

Indicator species

Species that provide early warnings of ecosystem damage (ex: trout).

Endangered species traits

Small range, requirements for large territory, or living on islands.

Natural pest control

$50-90\%$ of pests are controlled by predators, diseases, and parasites.

Insecticide groups

Chlorinated hydrocarbons (DDT), organophosphates (malathion), and carbamates (aldicarb).

Pesticide cons

Genetic resistance, ecosystem imbalance, pesticide treadmill, bioaccumulation, and biological magnification.

Petroleum formation

Microscopic aquatic organisms in sediments converted by heat and pressure into hydrocarbons.