AP Environmental Science

UNIT 1

Topic 1.1 Ecosystems

Ecosystem Basics

  • Community: all living organisms in an area

  • Ecosystem: all living & nonliving things in an area (plants, animals, rocks, soil, water

  • Biome: the plants and animals found in a given region (determined by climate

Organism Interactions

  • Competition: organisms fighting over a resource like food or shelter; limits population size

  • Predation: one organism using another for energy source (hunters, parasites)

  • Mutualism: relationship that benefits both organisms (coral reef)

  • Commensalism: relationship that benefits one organism & doesn’t impact the other (birds nests in trees)

Predation (+/-)

  • Herbivores: (plant eaters) eat plants for energy (giraffe & tree)

  • True predators: (carnivores) kill and eat prey for energy (leopard & giraffe)

  • Parasites: use a host organism for energy, often without killing the host & often living inside host

  • Parasitoids: lay eggs inside a host organism; eggs hatch & larvae eat host for energy

Symbiosis

  • Sym = together

  • Bio = living

  • osis = condition

  • Any close and long-term interaction between two organisms of different species

    • Mutualism (+/+), commensalism (+/O), and parsitism (+/-) are all symbiotic relationships

  • Mutualism: Organisms of different species living close together in a way that benefits both

Competition

  • Reduces population size since there are fewer resources available & fewer organisms can survive

    • Resource Partitioning: different species using the same resource in different ways to reduce competition

    • Temporal Partitioning: using resource at different times, such as woles & coyotes hunting at differnt times (night vs. day)

    • Spatial Partioning: using different areas of shared habitat

    • Morphological Partioning: using different resources based on different body features

Topic 1.2 Terrestrial (Land) Biomes

  • Biome: the plants & animals found in a region; based on yearly temperature + precipitation (climate)

    • The community of organisms (plants & animals) in a biome are uniquely adapted to live in that biome.

Biome Characteristics

  • Latitude (distance from equator) determines temperature & precipitation which is why biomes exist in predictable pattern on earth

  • Biome chart can also predict where on earth biomes are found

    • Tundra & Boreal = higher latitude (60 degrees +)

    • Temperate = mid latitude (30 degrees - 60 degrees)

    • Tropical = closer to the equator

Nutrient Availability

  • Tropical Rainforest = nutrient-poor soil

    • (High temperature & rainfall → rapid decomposition of organic matter; acidic soil + high rainfall → nutrient leaching)

  • Boreal Forest = nutrient-poor soil (low temperature & low decomposition rate of dead organic matter)

  • Temperate Forest = nutrient-rich soil (lots of dead organic matter - leaves & warm temperature/moisture for decomposition)

  • Plants need soil nutrients to grow, so availability determines which plants can survive in a biome

Shifting Biomes

  • Biomes shift in location on earth as climate changes

Topic 1.3 (Aquatic Biomes)

Characteristics of Aquatic Biomes

  • Salinity: how much salt there is in a body of water, determines which species can survive & usability for drinking (Fresh water vs. estuary vs. ocean)

  • Depth: influences how much sunlight can penetrate and reach plants below the surface for photosynthesis

  • Flow: Determines which plants & organisms cna survive, how much O2 can dissolve into water

  • Temperature: Warmer water holds less dissolved O2 so it can support fewer aquatic organisms

Freshwater: River & Lakes

  • Rivers hae high O2 due to flow mixing water & air, also carry nutrient-rich sediments (deltas & flood plains = fertile soil)

  • Lakes = standing bodies of fresh H2O (key drinking water source)

    • Littoral: shallow watter with emergent plants

    • Limnetic: where light can reach (photosynthesis)

      • No rooted plants, only phytoplankton

    • Profundal: too deep for sunlight (no photosynthesis)

    • Benthic: murky bottom where inverts (bugs) lie, nutrient-rich sediments

Freshwater: Wetlands

  • Wetland: area with soil submerged/saturated in water for at least part of the year, but shallow enough for emergent plants

    • Plants living here have to be adapted to living with roots submerged in standing water (cattails, lily pads, reeds)

      • Benefits of Wetlands

        • Stores excess water during storms, lessening flood damage to property

        • Recharges groundwater by absorbing rainfall into soil

        • Roots of wetland plants filter pollutants from water draining through

        • High plant growth rates due to lots of water & nutrients (dead organic matter) in sediments

Estuaries

  • Areas where rivers empty into the ocean

    • Mix of fresh & salt water (species adapt to this)

    • High productivity (plant growth) due to nutrients in sediments deposited in estuaries by river

      • Salt Marsh

        • Estuary habitat along coast in temperate climates

        • Breeding ground for many fish & shellfish species

      • Mangrove Swamps

        • Estuary habitat along coast of tropical climates

          • Mangrove trees with long, stilt roots stabilize shoreline & provide habitat for many species of fish & shellfish

Coral Reef

  • Warm shallow waters beyond the shoreline; most diverse marine (ocean) biome on earth

  • Mutualistic relationship between coral (animals) & algae (plants)

    • Coral take CO2 out of ocean to create calcium carbonate exoskeleton (the reef) & also provide CO2 to the algae

    • Algae live in the reef & provide sugar (energy) to the coral through photosynthesis

    • Both species rely on the other:'

      • Coral couldn’t survive without energy from algae

      • ALgae need the home of the reef & CO2 from the coral

Intertidal Zones

  • Narrow band of coastline between high & low tide

  • Organisms must be adpted to survive crashing waes & direct sunlight/heat during low tide

  • Shells & tough outer skin can prevent drying out (desiccation) during low tides

    • Different organisms are adapted to live in different Zones

Opean Ocean

  • So large that algae & phytoplankton of ocean produce a lot of earth’s O2 & absorb a lot of atmospheric CO2

    • Low productivity per m² as algae & phytoplankton can only survive in photic zone

    • Photic Zone = area where sunlight can reach (photosynthesis)

    • Aphotic Zone (abyssal) = area too deep for sunlight

      • Species rely on detritus from photic zone or chemosynthesis microbes at hydrothermal vents for energy

Topic 1.4 (Carbon Cycle)

Carbon Cycle Overview

  • Movement of molecules that contrain Carbon (CO2, glucose, CH4) between sources and sinks

    • Some steps are very quick (fossil fuel combustion), some are very slow (sedimentation & burial)

    • Leads to imbalance in which reservoirs or sinks are sotring carbon

  • Atmosphere is key Carbon reservoir: increasing levels of Carbon in atmosphere leads to global warming

  • Carbon Sink: reservoir that lake in more carbon that it releases

    • Ocean (algae & sediments), plants, soil

  • Carbon Source: reservoir that releases more carbon that it takes in

    • Fossil fuel (oil, coal, natural gas) combustion

    • Animal agriculture (cow burps & farts + CH4)

    • Deforestation, releases CO2 from trees

Photosynthesis & Cellular Respiation

  • Photosynthesis

    • Plants, algae, phytoplankton

    • Removes CO2 from the atmosphere & converts it to glucose

    • Glucose = biological form of Carbon & stored (chemical) energy in form of sugar

    • CO2 sink

  • Cellular Respiration

    • Done by plants & animals to release stored energy

    • Uses O2 to break glucose down & release energy

    • Releases CO2 into atmosphere

    • CO2 source (adds CO2 to atmosphere)

  • Both processes are very quick

  • Cycle Carbon between biosphere & atmosphere in balanced amount (no net Carbon increase in atmosphere)

Ocean & Atmosphere

  • Direct Exchange: CO2 moves directly between atmosphere & the ocean by dissolving into * out of ocean water at the surface

    • Happens very quicjly & in equal directions, balancing levels of CO2 between atmosphere & ocean

  • Because of direct exchange, increasing atmosphere CO2 also increases CO2, leading ocean acidification

  • Algae & phytoplankton take CO2 out of the ocean & atmosphere through photosynthesis

    • Coral, mollusks and some zooplankton also take CO2 out of the ocean to make calcium carbonate exoskeletons

  • Sedimentation: calcium carbonate precipitates out as sediments & settles on ocean floor

    • Burial: over long periods of time, pressure of water compresses Carbon-containing sediments on ocean floor into sedimentary rock (limenstone, sandstone) - long-term Carbon reservoir

Burial, Extraction, & Combustion

  • Burial: slow, geological process that stores Carbon in underground sinks like sedimentary rock or fossil fuels

    • Sediments (bits of rock, soil, organic matter) compacted into sedimentary rock by weight of overlying rock layers of water.

  • Fossil Fuels (FF): formed from fossilized remains of orgaic matter into coal (ex. plants) or oil (ex. plankton). Their decomposition produces natural gas (CH4)

  • Extraction & Combustion: digging up or mining Fossil Fuels & burning them as energy source; releases CO2 into atmosphere.

    • Burial (formation of Fossil Fuels) lakes for longer than extraction & combustion, which means they increase concentration of CO2 in atmosphere

Topic 1.5 (Nitrogen Cycle)

Nitrogen Cycle Overview

  • Movement of Nitrogen-containing molecules between sources & sinks/reservoirs

    • Sources release Nitrogen into atmosphere; sinks take Nitrogen out of the atmosphere in increasing amounts

  • Nitrogen reservoirs hold Nitrogen for relatively short periods of time compared to Carbon cycle

    • Ex: plants, soil, atmosphere

  • Atmosphere =main Nitrogen reservoir

    • Nitrogen in atmosphere exists mostly as N2 gas, which is not useable by plants or animals

  • Nitrogen = critical plant & animal nutrient

    • All living things need Nitrogen for DNA & amino acids to make proteins

Nitrogen Fixation

  • Process of N2 gas being converted into biologically available (useable by plants) NH3 (ammonia) or NO3- (nitrate)

  • Biotic Fixation: certain bacteria that live in the soil, or in the symbiotic relationship with plant root nodules convert N2 into ammonia (NH3)

    • Rhizobacteria live in root nodules of legumes (peas, beans) & fix Nitrogen for them in return for amino acids from the plant (mutualism)

  • Abiotic Fixation: Lightning converts N2 gas into nitrate (NO3-) and Foosil Fuel combustion converts N2 gas into ammonia (NH3)

    • NH3 is added to synthetic fertilizer and applied to agricultural soils (where its converted into nitrate)

Other Nitrogen Cycle Steps

  • Assimilation: plants & animals taking Nitrogen and incorporating into their biomas

    • Plant roots take in NO3- or NH3 from soil; animals assimilate Nitrogen by eating plants or other animals

  • Ammonification: soil bacteria, microbes & decomposers converting waste & dead biomass back into NH3 and returning it to soil

  • Nitrification: conversion of NH4 into nitrite (NO2-) & then nitrate (NO3-) by soil bacteria

  • Denitrification: conversion of soil Nitrogen (NO3) into nitrous oxide (N2O) gas which returns to atmosphere

Human Impacts on Nitrogen Cycle

  • Climate: N2O (nitrous oxide) = greenhouse gas which warm earth’s climate

    • Produced by denitrification of nitrate in agricultural soils (especially when waterlogged/over watered)

  • Leaching & Eutrophication: synthetic fertilizer use leads to nitrates (NO3) leaching, or being carried out of soil by water

    • Nitrates runoff into local waters, causing algae blooms that block sun & kill other aquatic plants

1.6 (Phosphorus Cycle)

Phosphorus Cycle Basics

  • Movement of Phosphorus atoms & molecules between sources & sinks/reservoirs

    • Rocks & sediments containg Phosphorus minerals = major reservoirs

      • Phosphorus cycle is very slow compared to Carbon/H2O/Nitrogen cycles

    • Takes a long time for Phosphorus minerals to be weathered out of rocks & carried into soil/bodies of water

    • No gas phase of Phosphorus (doesn’t enter atmosphere)

    • Because it cycles so slowly, it is a limiting nutrient, meaning plant growth in ecosystems is often limited by Phosphorus availability in soil/water

      • Phosphorus is needed by all organisms for DNA, ATP (energy), bone & tooth enamel in some animals

Phosphorus Sources

  • Major natural source of Phosphorus is weathering of rocks that contain Phosphorus minerals

    • Wind & rain break down rock & phosphate (PO4-3) is released and dissolved into water; rain water carries phosphate into nearby soils & bodies of water

      • Weathering is so slow that Phosphorus is often a limiting nutrient in aquatic & terresterial ecosystems

  • Synthetic (human) sources of Phosphorus = mining phosphate minerals & adding products like synthetic fertilizers & detergents/cleaners

    • Synthetic fertilizers containing phosphates are added to lawns or agricultural Fields; runoff carries Phosporus into nearby bodies of water

    • Phosphates from dtergents & cleaners enter bodies of water via wasterwater from homes

Assimilation & Excretion/Decomposition

  • Just like Nitrogen, Phosphorus is absorbed by plant roots & assimilates into tissues; animals assimilate Phosphorus by eating plants or other animals

  • Animal waste, plant matter & other biomass is broken down by bacteria/soil decomposers that return phosphate to soil

    • Assimilation & excretion/decomposition from a mini-loop within Phosphorus cycle just like assimilation & ammonification of Nitrogen cycle, photosynthesis & respirationin Carbon cycle.

Sedimentation & Geologic Uplift

  • Phosphate dosen’t dissolve very well into water; much of it forms solid bits of phosphate that fall to the bottom as sediment (sedimentation)

  • Phosphorus sediments can be compressed into sedimentary rock over long time periods by weight of overlying water

  • Geological Uplift = tectonic plate collision forcing up rock layers that form mountains; Phosphorus cycle can start over again with weathering & release of phosphate from rock

Eutrophication (too much Nitrogen & Phosphorus)

  • Can occur from fertilizer runoff, human/animal waste contamination

  • Because they’re limiting nutrients in aquatic ecosystems, extra input of Nitrogen & Phosphorus leads to eutrophication (excess nutriens) which fuels algae growth

    • Algae bloom coers surface of water, blocking sunlight & killing plants below surface

    • Algae eventually die-off; bacteria that break down dead algae use up O2 in the water (because decomposition = aerobic process)

    • Lower O2 levels (dissolved oxygen) in water kills aquatic animals, especially fish

    • Bacteria use up even more O2 to decompose dead aquatic animals

    • Creates positive feedback loop: less O2 → more dead organisms → more bacterial decomposition → less O2

Topic 1.7 (Hydrologic Cycle)

Water Cycle Overview

  • Movement of H2O (in different states) between sources & sinks

    • State of matter (solid/liquid/gas) as well as where water is moving are key in H2O cycle

      • Example: Precipitation = atmosphere (gas) → land or surface water (liquid)

    • Energy from sun drives the H2O cycle

      • Example: heat from sun causes liquid water in ocean to become a gas (evaporation) in atmosphere

    • Ocean = largest water reservoir

    • Ice caps & groundwater are smaller reservoirs, but contain fresh, useable water for humans

Evaportation & Evapotranspiration

  • 2 main sources of water (processes that cycle it from liquid on earth back into the atmosphere)

  • Sometimes called “vaportization” since liquid water becomes water vapor (gas) in atmosphere

  • Transpiration: process plants use to draw groundwater from roots up to their leaves

    • Leaf opening called stomata open, allowing water to evaporation into atmosphere from leaf

    • Movement of H2O out of leaf creates low H2O potential in leaf, pulling H2O up from roots

  • Evapotranspiration: amount of H2O that enters atmosphere from transpiration & evaporation combined

    • Both processes are driven by energy from the sun

Runoff & Infiltration

  • Precipitation (rain) either flows over earth’s surface into a body of water (runoff) or trickles through soil down into groundwater aquifers (infiltration)

    • Groundwater (aquifers) & surface waters (lakes/rivers) are important freshwater reservoirs for humans & animals

  • Precipitation recharges groundwater through infiltration, but only if ground is permeable (able to let water pass through)

  • Runoff recharges surface waters, but can also carry pollutants into water sources

Topic 1.8 (Primary Productivity)

PP Basics

  • units: kcal/m²/yr

    • kcal = energy

    • m² = area

    • yr = time

    • High PP = high plant growth = lots of food & shelter for animals

      • Ecosystems with high PP are usually more biodiverse (more diversity of species) than ecosystems with low PP

      • Primary Productivity: rate that solar energy is converted into organic compounds via photosynthesis over a unit of time

        • AKA: rate of photosynthesis of all producers in an area over a given period of time

        • Since photosynthesis leads to growth, you can also think of PP as the amount of plant growth in an area over a given period of time

Calculating PP

  • NPP = GPP - RL

    • Net Primary Productivity (NPP): The amount of energy (biomass) leftover for consumers after plants have used some for respiration

      • Think of NPP as the actual amount of the plant’s paycheck it keeps after taxes

    • Respiration Loss (RL): plants use up some of the energy they generate via photosynthesis by doing cellular respiration (movement, internal transportation, etc.)

      • Think of RL as taxes plant needs to pay

    • Gross Primary Productivity (GPP): The total amount of sun energy (light) that plants capture and convert to energy (glucose) through photosynthesis

      • Think of GPP as the total paycheck amount the plant earns

Ecological Efficiency

  • The portion of incoming solar energy that is captured by plants & converted into biomas (NPP or food available for consumers)

  • Generally, only 1% of all incoming sunlight is captured & converted into GPP via photosynthesis

    • (~99% of solar energy comes in waelengths plants can’t use for photosynthesis & is reflected by or passes through them)

  • Of that 1%, an average 40% (or 0.4% of total incoming solar energy) is converted into biomass/plant growth (NPP)

    • Some ecosystems are more efficient (higher NPP) than others

Trends in Productivity

  • The more productive a biome is, the wider the diversity of animal life it can support (higher biodiversity)

  • Water availability, higher temperature, and nutrient availability are all factors that lead to high NPP

    • Shortage of any of these three factors will lead to decreased NPP

Topic 1.9 (Trophic Levels)

Conservation of Matter & Energy

  • Matter & Energy are never created or destroyed: they only change forms

    • Example: Tree dies & the Carbon/Nitrogen/H2O/Phosphorus are returned to the soil & atmosphere

  • 1st Law of Thermodynamics: Energy is never created or destroyed

    • Biogeochemical cycles demonstrate conservation of matter (Carbon/Nitrogen/H2O/Phosphorus)

  • Food Webs demonstrate conservation of energy

    • Example: When a rabbit earts a leaf, the energy from the leaf (glucose) is transfered to the rabbit & stored as body tissue like fat/muscle

2nd Law of Thermodynamics

  • Each time energy is transferred some of it is lost as heat

    • Applied to food webs: the amount of useable energy decreases as you move up the food chain (organisms use up most of it for movement, development, etc.)

    • Because available energy decreases with each step up the food chain, a trophic pyramid (troph = nourishment or growth) is used to model how energy moves through an ecosystem

Topic 1.10 (The 10% Rule)

  • 10% Rule: In trophic pyramids, only about 10% of the energy from one leel makes it to the next level; the other 90% is used by the organisms & lost as heat

Trophic Levels & 10% Biomass

  • Tertiary Consumers: animals that eat secondary consumers or carnivores & omnivores (aka - top/apex predators)

  • Secondary Consumers: animals that eat primary consumers or herbivores (aka - carnivores & omnivores)

  • Primary Consumers: animals that eat plants (herbivores)

  • Producers: (plants) “produce” - really convert sun’s light energy into chemical energy (glucose)

  • 10% rule also spplies to biomass (or mass of all liing things at each trophic level)

    • Since energy is needed for growth & only 10% of energy transfers from one level to the next, only 10% of the biomass of the previous trophic level can be grown/supported by the available energy

Topic 1.11 (Food Chains & Food Webs)

Food Web Basics

  • Shows how matter & energy flow trhough an ecosystem, from organism to organism

  • When one organism preys on (eats) another, the matter (Carbon/Hydrogen/H2O/Phosphorus) and energy (glucose, muscle tissue, etc.) are passed on to the predator

    • Arrows in the food webs indicate direction of energy flow (point to the organism taking the in the energy)

Food Web vs. Chain

  • Food chains just show one, linear path of energy & matter

  • Food webs have at least 2 different, interconnected food chains

    • Webs show that organisms can exist at different trophic levels

      • Grass → hare → owl (secondary consumer)

      • Grass → grasshoper → robin → owl (tertiary consumer)

Interactions & Trophic Cascade

  • Food webs show how increase or descreases in population size of a given species impact the rest of the food web

    • Example: Increase in python population

      • Decrease in frog & rat population

      • Increase in grasshopper population

      • Decrease in corn

  • Trophic Cascade: removal or addition of a top predator has a ripple effect down through lower trophic levels

    • Example: decline in wolf population = increase in deer population which leads to overgrazing & decline in trees

UNIT 2

Topic 2.1 (Intro to Biodiversity)

Biodiversity Basics

  • Diversity of life forms in an ecosystem; measured on 3 different levels:

    • Ecosystem Diversity: the number of different habitats available in a given area

    • Species Diversity: the number of diferent species in an ecosystem and the balance or eveness of the population sizes of all species in the ecosystem

    • Genetic Diversity: how different the fenes are of individuals within a population (group of the same species)

  • Higher Biodiversity = higher ecosystem/population health

Species Richness & Evenness

  • Richness (S) i just the total number of different species found in na ecosystem

    • High richness is generally a good sign of ecosystem health (more species means more quality resources like H2O & soil)

  • Evenness is a measure of how all of the individual organisms in an ecosystem are balanced between the different species

    • Evenness indicates if there are one or two dominant species, or if population sizes are well balanced

Genetic Diversity is Beneficial

  • Genetic Diversity = measure of how different the genomes (set of genes) are of the individuals within a population of a given species

    • There is a genetic diversity in all populations because random mutations in copying of DNA & recombination of chromosomes in sex cells of parents leads to new gene combinations & new traits in offspring

      • The more genetic diversity in a population the better the population can respond to environmental stressors like drought, disease, or famine

        • More genetic diversity = high chance that some of the individuals in a population have traits that allow them to survive the environmental stressor

Bottleneck Event

  • Any environmental disturbance (natural disaster/human habitat destruction) that drastically reduces population size & kills organisms regardless of their genome

  • Survivng population is smaller and because individual died randomly, it doesn’t represent the genetic diversity of the original population

    • Bottleneck evens reduce genetic diversity

      • Because the population is smaller & less genetically diverse, it’s even more vulnerable to future environmental disturbances

Inbreeding Depression

  • Inbreeding is when organisms mate with closely related “family” members

    • Leads to higher chance of offspring having harmful genetic mutations because they’re geting similar genotypes from both parents

  • Smaller populations are more likely to experience inbreeding (difficult to find non-related mate)

Ecosystem Resilience

  • Resilience: the ability of an ecosystem to return to its orginal conditions after a major disturbance (wind storm, fire, flood, clear-cutting, etc.)

    • Higher species diversity = higher ecosystem resilience

      • High species diversity means more plant species to repopulate disturbed ground, anchor soil, and provide food & habitat for animal species

Topic 2.2 (Ecosystem Services)

Ecosystem Services = $$$

  • Goods and services provided by natural ecosystems that are beneficial to humans (often monteraily or life-sustaining)

    • Provisioning: goods taken directly from ecosystems or made from natural resources (wood, paper, food)

    • Regulating: natural ecosystems regulate and stabilize climate, air quality, water quality, soil, biodiversity

    • Supporting: natural ecosystem processes that sustain ecosystems & allow them to support life

    • Cultural: Money generate by recreation (parks, camping, tours) or scientific knowledge

Humans Disrupt Ecosystem Services

  • Human activities disrupt the ability of ecosystems to function, which decreases the value of ecosystem services they provide

    • This has ecological (natral) and economic (money-based) consequences

    • Examples:

      • Clearing land for agriculture/cities removes trees that store CO2 (more CO2 in atmosphere = increased atmospheric temperatre = more storm damage & crop failure)

      • Overfishing leads to fish population collaspe (lost fishing jobs and lower fish sales in the future)

Provisioning Services

  • Goods/products directly provided to humans for sale/use by ecosystems

    • Example: Fish, hunting animals, lumber (wood for furniture/buildings), naturally grown foods like berries, seeds, wild grains, honey

  • Goods/products that are made from natural resources that ecosystems provide

    • Example: paper, medicine, rubber

  • Disrupted by overharvesting, water pollution, clearing land for agriculture/urbanization

Regulating Services

  • Benefit provided by ecosystem processes that moderate natural conditions like climate, air quality, biodiversity, soil quality

  • Examples:

    • Filtration & purification of water by wetlands

    • Pollination (aids plnat reproduction, food production, biodiversity)

    • Trees sequester CO2 via photosynthesis, lessening atmospheric warming & costly impacts like storm damage/crop loss

    • Trees filter air by absorbing air pollutants which reduces health care costs for treating diseases like asthma and bronchitis

  • Disrupted by deforestation, pollinator habitat loss, filling in wetlands

Supporting Services

  • Natural processes that sustain ecosystems, allowing them to support life and all of the other ecosystem services

  • Examples:

    • Photosynthesis, soil creation, nutrient cycling, habitat & food creation for plants and animals (all of these processes support ecosystem function, allowing them to support life)

    • Essentially, everything needed to maintain functioning ecosystems, supporting all of the other ecosystem services

  • Habitat loss due to deforestation, agriculture, urbanization

A Note On Supporting vs. Regulating Services

  • There is some overlap in classification of regulating and supporting services, depending on the context of the process

    • AP Classroom and the UN Food and Agriculture Organization classify pollination as a regulating ecosystem service, because it assists plant reproduction, fruit production, fostering biodiversity. They both classify water purification/treatment as regulating, since ecosystems like wetlands regulate water quality by removing pollutants

    • Friedland 4th edition classifies pollination as supporting since it aids human agriculture and makes it more productive. It also classifies water filtration by ecosystems as supporting, since they reduce the cost humans need to pay to purify water.

Cultural Services

  • Revenue from recreational activities (hunting/fishing licesnes, park fees, tourism-related spending) & profits from scieintific discoeries made in ecosystems (health/agriculture/educational knowledge)

  • Examples:

    • Beuatiful landscapes draw tourists who pay to enter parks, spend money at local stores/restaurants, or camping fees

    • Fishermen pay for fishing licenses to catch fish in clean rivers

    • Scientists learn about plant compounds that cna lead to creation of new medicines which are sold for profit

  • Dirupted by deforestation, pollution, urbanization

Topic 2.3 (Theory of Island Biogeography)

Island Bipgeography

  • Study of ecological relationships & community structure on islands

    • Islands can be actual islands in a body of water, or figuratie habitat islands such as Central Park in New York City or National Parks (natural habitats surrounded by human-developed land)

  • Two basic “rules” or observations of Island Biogeography:

    • Larger Islands support more total species

      • The larger the island, the greater the ecosystem diversity

      • Greater ecosystem diversity = more food & habitat resources

      • More niches, or “roles” organisms can play in the ecosystem

    • Islands closer to the “mainland” support more species

      • Easier for colonizing organisms to get to island from the mainland

      • More colonizing organisms = more genetic diversity in new population

Larger Islands Support More Species

  • Larger islands =

    • higher ecosystem diversity

    • More available “niches” or roles

      • Example: all the different food sources available to birds on Galapagos

    • Larger population sizes (more genetically diverse and more resistant to environmental disturbance)

    • Lower extinction rate (species less likely to die off)

  • Positive correlation between island size & species richness

Distance to Mainland

  • Closer to mainland = higher species richness

    • Easier for more species to migrate to island from mainland (swim/fly)

    • More continual migration of individuals to the island habitat

      • Frequent migration brings more genetic diversity & larger population size

    • Inverse relationship between island distance from mainland & species richness

      • The further away from mainland, the fewer species

Topic 2.4 (Ecological Tolerance)

Ecological Range of Tolerance

  • Range of conditions such as temperature, salinity, pH, or sunlight that an organism can ednure before injury or death results

  • Species and individual organisms both have a range of tolerance for all the different abiotic conditions of their habitat

    • Example: Salmon have a basic range of tolerance for temperature from 6 degrees to 22 degrees Celsius. But some individual salmon have adaptations that give them a range of tolerance that is outside the basic range for the species

      • Due to genetic biodiversity

      • Makes populations of salmon more resistant to disturbances, like global warming

Ecological Range of Tolerance - Zones

  • Optimal Range: range where organisms survive, grow, and reproduce

  • Zone of Physiological Stress: range where organisms survive, but experience some stress such as infertility, lack of growth, decreased activity, etc.

  • Zone of Intolerance: range where the organism will die

    • Example: thermal shock, suffocation, lack of food/water/oxygen

FRQ Writing Tips

  • On FRQs about human activities or natural events that cause environmental disturbance, connect answer to ecological range of tolerance

  • If possible, connect human activity to climate change

    • (electricity generation, transportation, agriculture) all release CO2 which causes climate change and global warming

      • Global warming shift temperature outside the range of tolerance for many tree species, causing their populations to decline

      • Global warming warms the ocean, shifting temperature outside range of tolerance for many fish species, causing die-offs

  • Try to connect a shift in range of tolerance to a specifc kind of physiological stress

    • Example: suffocation, thermal shock, lack of water/food/nutrients/oxygen

      • Global warming warms the ocean, shifting temperature outside range of tolerance for many fish species. Since global warming increases ocean temperature and warm water holds less oxygen, fish may suffocate due to lack of oxygen

      • Global warming can increase droughts. With increased droughts, rainfall patterns may shift outside the range of tolerance for many plant species. Without enough rainfall, these specise may suffer population decline as their roots are unable to absorb enough water from the soil.

Topic 2.5 (Natural Disruptions to Ecosystems)

Natural Disturbances

  • A natural event that disrupts the structure and or function of an ecosystem

    • Example: Tornadoes, hurricanes, asteroids, forest fires, drought

  • Natural disturbances can be even greater than human disruptions

    • Can occur on periodic, episodic, or random time frames

  • Periodic: occurs with regular frequency (example: dry-wet seasons)

  • Episodic: occasional events with irregular frequency (example: hurricanes, droughts, fires)

  • Random: no regular frequency (volcanoes, earthquakes, and asteroids)

Natural Climate Change

  • Earth’s climate hasvaried over geologic time for numerous reasons

    • Example: slight changes in earth’s orbit & tilt cause mini ice ages & warmer periods as earth shifts slightly closer to & further from sun

  • Sea level has varied over gelogical time as glacial ice on earth melts & forms

Environmental Change = Habitat Disruption

  • Major environmental disturbances result in widespread habitat changes and or loss

    • Example: rising sea level floods coastal & estuary habitats

Migration

  • Wildlife may migrate to a new habitat as the result of natural disruptions

    • Example: wildebeests migrating to follow rain patterns of African savanna

      • Ocean species moving further north as water temperature warms

      • Bird migration & breeding shifting earlier as insect hatching shifts earlier with warming climate

Topic 2.6 (Adaptations)

Fitness & Adaptation

  • All populations have some genetic diversity, or variability in genomes of individuals; Genetic diversity exists because:

    • Random mutations while DNA is being copied create new traits

    • Crossing over in parent chromosomes creates new combinations of genes (and therefore traits)

  • Adapation: a new trait that increases an organism’s fitness (ability to survive and reproduce)

Adaptation & Natural Selection

  • Natural Selection: organisms that are better adapted to their environment survive and reproduce more offspring

    • Individuals with adaptations pass them on to offspring & individuals without adaptations die off, which leads to the entire population having the adaptation over time (evolution)

      • Selective Pressure/Force: the environmental condition that kills individuals without the adaptation.

Environmental Change & Evolution

  • The environment an organism lives in determines which traits are adaptations

    • As environments change, different traits may become adaptations & old traits may become disadvantages

      • Example: a drought can kill off finches with smaller beaks, making larger beaks for cracking harder seeds an adaptation

Pace of Evolution

  • The more rapidly an environment changes, the less likely a species in the environment will be to adapt to those changes

    • If the pace of enevironment change is too rapid, many species may migrate out of the environment or die-off completely

      • Example: if the ocean warms too quickly (decreases dissolved O2), many species of fish may not be able to migrate quickly enough to colder waters

  • The more genetic diversity in a population, the better they’re able to adapt to environmental change (higher chance that some individuals have good mutations)

    • The longer the lifespan of the organism, the slower the rate of evolution

      • Example: bacteria & viruses can adapt and evolve in days

        • Humans evolution = thousand-million years

Topic 2.7 (Ecological Succession)

Ecological Succession

  • A series of predictable stages of growth that a forest goes through two types of succession

    • Primary Succession: starts from bare rock in an area with one previous soil formation

      • Moss & lichen spores carried by the wind grow directly on rocks, breaking them down to form soil

    • Secondary Succession: starts from already established soil in an area where a disturbance (fire/tornado/human land clearing) cleared out the majority of plant life

      • Grasses, sedges, wildflowers, and berry bushes have seeds disperesed by wind or animal droppings

Stages of Succession

  • Stages are characterized by which types of plant species dominate the ecosystem; different species are adapted to the conditions of the different stages

    • Pioneer or early succession species appear first, when the ground is simply bare rock, or bare soil after a disturbance

      • Characteristics: seeds spread by wind or animals, fast growing, tolerant of shallow soil and full sunlight

        • Example: moss, lichen (bare rock) | wildflowers, raspberries, grasses/sledges

    • Mid-successional species appear after pioneer species have helped develop deeper soil with more nutrients by their cycles of growth/death

      • Characterisitcs: relatively fast growing, larger plants that need deeper soils with more nutrients than pioneers, sun tolerant

        • Example: shrubs, bushes, fast-growing trees like aspen, cherry, and pine

    • Late successional or climax community species appear last, after soil is deepened and enriched with nutrients by cycles of growth and death by early & mid successional species

      • Characteristics: large, slow-growing trees that are tolerant of shade and require deep soils for alrge root networks

        • Example: maples, oaks, other large trees

Primary Succession

  • Occurs in an area that hasn’t previously been clonized by plants (bare rock)

    • Example: volcanic rock, rock exposed after glacial retreat

    • Moss and Lichen (spores dispersed by wind) are able to grow directly on rock by secreting acids that break down rock & release minerals containing nutrients they need (Nitrogen/Phosphorus/Potassium)

      • Chemical weathering of rocks by moss & lichen combined with organic matter from moss & lichen dying form initial shallow soil

Secondary Succession

  • Occurs in an area that already has established soil, but has had most plant life removed by a disturbance

    • Pioneer species are still wind-dispersed seeds of plants that are fast-growing and sun tolerant, but grasses/wildflowers/weeds instead of moss/lichen

    • Soil is already established & sometimes even enriched by nutrient-rich ash from fire; overall more rapid process than primary succession

UNIT 3

Topic 3.1 (Specialist vs. Generalist Species)

  • Specialists: smaller range of tolerance, or narrower ecological niche makes them more prone to extinction

    • Specific food requirements (bamboo)

    • Less ability to adapt to new conditions

  • Generalists: larger range of tolerance, broader niche makes them less prone to extinction & more likely to be invasive

    • Broad food requirements

    • High adaptability

Topic 3.2 (K-selected & r-selected species)

Quality vs. Quantity

  • K-slected = “quality”

    • Few offspring, heavy parental care to protect them

    • Generally have fewer reproductive events that r-strategists

      • Example: most mammals, birds

    • Long lifespan, long time to sexual maturity = low biotic potential = slow population growth rate

      • More likely to be disrupted by environmental change or invasive species

  • r-selected = “quantity"

    • Many offspring, little to no parental care

    • May reproduce only once, but generally reproduce many times throughot lifespan

      • Example: insects, fish, plants

    • Shorter lifespan, quick to sexual maturity = high biotic potential = high population growth rate

      • More likely to be invasive

      • Better suited for rapidly changing environmental conditions

Habitats/Populations

  • K-selected:

    • Usually live in habitats with higher competition for resources

    • Populations that reach carrying capacity (K) usually remain at stable size, near K

      • Hence, K-selected or K-strategist

  • r-selected:

    • Usually live in habitats with lower competition for resources

    • Population are more likely to fluctuate above and below carrying capacity (overshoot and die-off)

      • “r” is the variable used to represent maximum reproductive rate in ecology

      • Hence, r-selected or r-stategist

Invasiveness & Disturbances

  • K-selected:

    • Low biotic potential (reproduction rate) = hard for population to recover after a disturbance (environmental change)

    • High parental care means death of parent = death of offspring

    • Invasives (usually r) outcompete for resources with high biotic potential & rapid population growth

    • Less likely to adapt & more likely to go extinct

  • r-selected:

    • High biotic potential (reproduction rate) = more rapid population recovery after disturbance

    • Low parental care means death of parent doesn’t impact offspring

    • Not as impacted by invasive species since their population grows quickly

      • More likely to be the invasive

    • Larger population & faster generation time = higher chance of adaption & lower chance of extinction

Topic 3.3 (Survivorship Curves)

Survivorship Curve: line that shows survival rate of a cohort (group of same-aged indivduals) in a population from birth to death

  • Faster drop in line = quicker die-off of individuals

  • Slower drop in line = longer average lifespan

Type I, II, and III Survivorship

  • Type I (mostly K-selected)

    • High survivorship early in life due to high parental care

    • High survivorship in mid life due to large size & defensive behavior

    • Rapid decrease in survivorship in late life as old age sets in

      • Example: most mammals

  • Type II (in between r & K)

    • Steadily decreasing survivorship

  • Type III (mostly r-selected)

    • High mortality (low survivorship) early in life due to little to no parental care

    • Few make it to midlife; slow, steady decline in survivorship in mid life

    • Even fewer make it to adulthood; slow decline in survivorship in old age

      • Example: insects, fish, plants

Topic 3.4 (Carrying Capacity)

Carrying Capacity (K): the maximum Number of individuals in a population that an ecosystem can support (based on limiting resources)

Carrying Capacity (K)

  • Highest population size an ecosystem can support based on limiting resources:

    • Food

    • Water

    • Habitat (nesting sits, space)

  • Overshoot: when a population briefly exceeds carrying capacity

    • Example: deer breed in fall, give birth all at once in spring; sudden spike in population = overshoot

  • Consequence of overshoot: resource depletion

    • Example: overgrazing in deer

  • Die-off: sharp decrease in population size when resource depletion (overshoot) leads to many individuals dying

    • Example: many deer starve with too many new fawns feeding in spring

Topic 3.5 (Population Growth & Resource Availability)

Population Characteristics

  • Size (N): total number of individuals in a given area at a given time

    • Larger = safer from population decline

  • Density: number of individuals/area

    • Example: (12 panthers/km²)

    • High density = higher competition, possibility for disease outbreak, possibility of depleting food source

  • Distribution: how individuals in population are spaced out compared to each other

    • Random (trees)

    • Uniform (territorial animals)

    • Clumped (herd/group animals)

Population Characteristics & Growth Factors

  • Sex Ratio: ratio of males to females. Closer to 50:50, the more ideal for breeding (usually)

    • Die-off or bottleneck effect can lead to skewed sex ratio (not enough females) limiting population growth

  • Density-Dependent Factors: factors that influence population growth based on size:

    • Example: food, competition for habitat, water, light, even disease

    • All of these things limit population growth based on their size; aka - small population don’t experience these, large do

  • Density-Independent Factors: factors that inflence population growth independent of their size

    • Example: natural disasters (flood, hurricane, tornado, fire)

    • It doesn’t matter how big or small a population is, natural disasters limit them both

  • Biotic Potential = maximum potential growth rate, with no limiting resources - also called intrinsic rate of increase

    • May occur initially, but limiting resources (competition, food, disease, predators) slow growth, & eventually limit population to carrying capacity (K)

    • Exponential growth

  • Logistic growth = initial rapid growth, then limiting factors limit population to K

Calculating Population Change

  • Population Size = (Immigrations + births) - (emigrations + deaths)

    • Example: An elk population of 52 elk has 19 births & 6 deaths in a season, and 5 new elk immigrate to the herd and 0 elk emigrate from the herd

      • (19+5) - (6+0) = 18 elk

        • 52 + 18 = 70 elk

Topic 3.6 (Age Structure Diagrams)

Age Cohorts

  • Age cohorts & growth = groups of similarly aged individuals

  • 0-14 prereproductive; 15-44 = reproductive age; 45+ = post reproductive

  • Size difference between 0-14 ^ 15-44 indicates growth rate

    • Larger 0-14 cohort = current & future growth

    • Roughly equal 0-14 & 15-44 = slight growth/stable

    • Larger 15-44 = population decline

  • Extreme Pyramid Shape = rapid growth

  • Less extreme pyramid = slow, stable growth

  • House = stable, little to no growth

  • Narrowest at base = declining population

Topic 3.7 (Total Fertility Rate)

Total Fertility Rate & Infant Mortality

  • Total Fertility Rate (TFR): average number of children a woman in a population will bear throughout her lifetime

    • Higher Total Fertility Rate = higher birth rate, higher population growth rate (generally)

  • Replacement Level Fertility: the Total Fertility Rate require to offset deaths in a population and keep population size stable

    • About 2.1 in developed countries (replace mom & dad)

    • Higher than 2.1 in less developed countries due to higher infant mortality

  • Infant Mortality Rate (IMR): number of deaths of children under 1 year per 1,000 people in a population

    • Higher in less developed countries due to lack of access to: health care, clean water, enough food

    • Higher Infant Mortality Rate = higher Total Fertility Rate, due to families having replacement children

Infant Mortality & Total Fertility Rate

  • Factors in Infant Mortality Rate Decline

    • Acces to clean water

    • Access to healthcare (hospitals, vaccines, vitamins & supplements for moms & babies)

    • More reliable food supply

Factors that Affect Total Fertility Rate

  • Development (Affluence): more developed, or wealthy nations have a lower Total Fertility Rate than less developed nations

    • More eduational access for women

    • More economic opportunity for women

    • Higher access to family planning education & contraceptives

    • Later age of first pregnancy

    • Less need for children to provide income through agricultural labor

  • Government Policy: can play a huge role in fertility by coercive (forceful) or noncoercive (encouraging) policies

    • Forced sterilization

    • China’s 1 (now 2) child policy

    • Tax incentives to have fewer children

    • Microcredits or loans to women without children to start businesses

Topic 3.8 (Human Population Dynamics)

Does Earth Have a Human Carrying Capacity?

  • Malthusian theory:

    • Earth has a human carryin capacity, probably based on food production

    • Human population growth is happening faster than growth of food production

    • Humans will reach a carrying capacity limited by food

  • Technological Advancement

    • Humans cna alter earth’s carrying capacity with technogical innovation

      • Example: synthetic fixation of Nitrogen in 1918 leads to synthetic fertilizer, dramatically increasing food supply

Birth Rate, Death Rate, and Growth

  • Growth Rate r = % increase in a population (usually per year)

    • Example a growth rate of 5% for a population of 100 means they grow to 105

  • Crude Birth Rate & Crude Death Rate (CBR & CDR)

    • Births & deaths per 1,000 people in a population

      • Example: Global CBR = 20 & CDR = 8

    • Calculating Growth Rate

      • [Crude Birth Rate - Crude Death Rate] / 10

        • [20 - 8] / 10

          • 1.2 percent

Doubling Time (Rule of 70)

  • Rule of 70: The time it takes (in years) for a popultion to double is equal to 70 divided by the growth rate

    • Example: Global growth rate = 1.2%

      • 70/1.2 = 58.3 years

        • Global population will double in 58.3 years

Factors Affecting Human Population Growth

  • Factors that increase population growth

    • Higher Total Fertility Rate → higher birth rate

    • High infant mortality rate can drive up Total Fertility Rate (replacement children)

    • High immigration level

    • Increased access to clean water & healthcare (decrease death rate)

  • Factors that decrease population growth rate

    • High death rate

    • High infant mortality rate

    • Increase development (education & affluence)

    • Increased education for women

    • Delayed age of first child

    • Postponement of marriage age

Standard of Living Indicators

  • Standard of Living

    • What the quality of life is like for people of a country absed

  • Gross Domestic Product (GDP) = key economic indicator of standard of living

    • Total value of the goods & services produced

    • Per capita GDP is total GDP/total population

  • Life expectancy = key health indicator of standard of living

    • Average age a person will live to in a given country

    • Increases with access to clean water, health care, stable food sources

Topic 3.9 (Demographic Transition)

Industrialization

  • Indsutrialization: the process of economic and social transition from an agrarian (farming0 economing to an industrial one (manufacturing based)

  • Pre-industrialized/Less developed

    • A country that has not yet made the agrarian to indsutrial transition

    • Typically very poor (low GDP)

    • Typically high death rate & high infant mortality

    • High Total Fertility Rate for replacement children & agricultural labor

  • Industrializing/developing

    • part way through this transition

    • Decreasing death rate & Infant Mortality Rate

    • Rising GDP

  • Industrialized/developed: completed the transition

    • Very low Crude Death Rate & Infant Mortality Rate

    • Very high GDP

    • Low Total Fertility Rate

Stage 1 - Preindustrial

  • High Infant Mortality Rate & high death rate due to lack of access to clean water, stable food supply, and healthcare

  • High Total Fertility Rate due to lack of access to:

    • Education for women

    • Contraceptives/family planning

  • Need for child agricultural labor

  • Little to no growth due to high Crude Birth Rate & Crude Death Rate balancing each other out

    • Example: Virtually no country is in phase 1

Stage 2 - Indsutrializing/Developing

  • Modernizations bring access to clean water, healthcare, stable food supply

    • Infant Mortality Rate & Crude Death Rate decline

  • Total Fertility Rate remains high due to

    • Lack of education for women & contraceptives/family planning

    • Need for child agricultural labor

    • Generational lag (takes time for education & societal change to spread)

  • Rapid growth, due to high Crude Birth Rate & declining Crude Death Rate

  • Economical/Societal Indicators

    • Low per capita GDP

    • Shorter life-expectancy

    • High infant mortality

    • High Total Fertility Rate

    • Low literacy rate & school life expectancy for girls

Stage 3 - Developed/Industrialized

  • Modernized economy and society increase family income, so Total Fertility Rate declines significantly due to

    • More education oppportunities for women

    • Delayed age of marriage & first child to focus on education/carrer

    • Access to family planning & contraceptives

  • Slowing growth rate as Crude Birth Rate drops closer to Crude Death Rate

  • Economical/societal Indicators

    • High per capita GDP

    • Long life-expectancy

    • Low infant mortality

    • Total Fertility Rate near replacement level (2.1)

    • High literacy rate & school life expectancy for all

Stage 4 - Post-Industrialized/Highly Developed

  • Highly modernized countries that a very affluent

    • Total Fertility Rate declines even further as families become more wealthy and spend even more time on educational & career pursuits

    • Increased wealth & education brings even more prevalent use of family planning & contraception

  • Crude Birth Rate drops lower than Crude Death Rate & growth becomes negative (population decline)

  • Economical/societal Indicators

    • Very high per capita GDP

    • Longest life-expectancy

    • Total Fertility Rate below replacement level (2.1)

    • Highest contraceptive use rates

UNIT 4

Topic 4.1 (Plate Tectonics)

Earth’s Structure

  • Core: Dense mass of nickel, iron, and radioactive elements that release massive amounts of heat

  • Mantle: bulk of Earth’s interior; three layers

    • Magma (molten rock) layer that slowly circulates due to heat from core

    • Asthenosphere: semi-molten, flexivle outer layer of mantle, beneath the lithosphere

    • Lithosphere: thin, brittle layer of rock floating on top of mantle (broken up into tectonic plates)

      • Crust: very outer layer of the lithosphere, Earth’s surface

Plate Boundaries

  • Divergent Plate Boundary

    • Plates move away from each other

    • Rising magma plume from mantle forces plates apart

      • Forms: mid-oceanic ridges, volcanoes, seafloor spreading, and rift valleys (on land)

  • Transform Fault Plate Boundary

    • Plates slide sideways past each other

      • Forms: faults (fracture in rock)

  • Convergent Plate Boundary

    • Plates move towards each other

    • Leads to subduction (one plate being forced beneath another)

      • Forms: mountains, island arcs, and volcanoes

Mantle Convection Currents

  • Magma heated by earth’s core rises towards lithosphere

  • Rising magma forces oceanic plates apart

    • Creates mid ocean ridges, volcanoes, spreading zones or “seafloor spreading”

  • Magma cools and solidifies into new lithosphere at spreading zone

  • Spreading magma forces oceanic plate under continental plate

    • Sinking oceanic plate melts back into magma

    • New magma is forced up, creating narrow, coastal mountains (e.g. Andes) & volcanoes on land

Convergent Boundaries

  • Oceanic-Oceanic: one plate subducts underneath other

    • Forces magma up to lithosphere surface, forming mid ocean volcanoes

      • Island arcs

    • Off-shore trench

  • Oceanic-Continental: dense oceanic plate subducts bentah continetal plate & melts back into magma

    • Forces magma up to lithosphere surface

    • Coastal Mountains (Andes), Volcanooes on land, trenches, tsunamis

  • Continental-Continental: surface crust from both plates “buckles” upward (mountains)

    • Example: Himalayas

Transform Fault Boundary

  • Plates sliding sideways past each other; can create a fault (fracture in rock surface)

    • Eathquakes occur when rough edges of plates get stuck on each other

    • Pressure builds as plates keep sliding, but edges stay stuck

    • When stress overcomes the locked fault, plates suddenly release, slide past each other and release energy that shakes the lithosphere

Tectonic Map Can Predict…

  • Ring of Fire: pattern of volcanoes & eathquake zones all around pacific plate

    • Offshore island arcs (Japan)

  • Transform faults: likely location of earthquakes

  • Hotspots: areas of especially hot magma rising up to lithosphere

    • Mid-ocean Islands (Iceland, Hawaii)

Topic 4.2 (Soil Formation & Erosion)

What is Soil?

  • Mix of geologic (rock) and organic (living) components

    • Sand, silt, clay

    • Humus: main organic part of soil (broken down biomass like leaves, dead animals, waste, etc.)

    • Nutrients: ammonium, phosphates, nitrates

    • Water and Air

    • Living Organisms

  • Plants: anchors roots of plants and provides water, shelter, nutrients (Nitrogen, Phosphorus, Potassium, Magnesium) for growth

  • Water: filters rainwater + runoff by trapping pollutants in pore spaces + plant roots. Clean water enters groundwater + aquifers

  • Nutrient Recycling: home to decomposers that break down dead organic matter + return nutrients to the soil

  • Habitat: provides habitat for organisms like earthworms, fungi, bacteria, moles, slugs

Weathering

  • Breakdown of rocks into smaller pieces

    • Physical (wind, rain, freezing/tthawing of ice)

    • Biological (roots of trees rack rocks)

    • Chemical (acid rain, acids from moss/lichen)

  • Weathering of rocks = soil formation

    • Broken into smaller and smaller pieces

    • Carried away and deposited by erosion

Erosion

  • Transport of weathered rock fragments by wind and rain

  • Carried to new location and deposited (deposition)

Soil Formation

  • From below

    • Weathering of parent material produces smaller, and smaller fragments that make up geological/inorganic part of soil

      • Sand, silt, clay

      • Minerals

  • From above

    • Breakdown of organic matter adds humus to soil

    • Erosion deposits soil particles from other areas, adding to soil

Effects on Soil Formation

  • Parent material: soil pH, nutrient content

  • Topography: steep slope = too much erosion; more level ground = deposition

  • Climate: warmer = faster breakdown of organic matter; more precipitation = more weathering, erosion + deposition

  • Organisms: Soil organisms like bacteria, fungi, worms breakdown organic matter

Soil Horizons

  • O-Horizon: layer of organic matter (plant roots, dead leaves, animal waste, etc) on top of soil

    • Provides nutrients and limits H2O loss to evaporation

  • A-Horizon: aka topsoil; layer of humus (decomposed organic matter) and minrals from parent material

    • A-Horizon has most biological activity (earthworms, soil microbes) breaking down organic matter to release nutrients

  • B-Horizon: aka subsoil; lighter layer below topsoil, mostly made of minerals with little to no organic matter

    • Contains some nutrients

  • C-Horizon: least weathered soil that is closest to the parent material, sometimes called bedrock

  • Soil Degradation: The loss ability of soil to support plant growth

UNIT 7

Topic 7.1 (Introduction to Air Pollution)

Air Pollution Basics

  • Write about air pollutants (specific molecules/particles) not just air “pollution” as an idea

  • Clean Air Act (1970) identified 6 criteria air pollutants that the EPA is required to set acceptable limits for, monitor, and enforce

    • SO2 (Sulfur Dioxide)

      • Coal combustion (electricity) | respiration irritation | smog | acid precipitation

    • NOx (Nitrogen Oxides; NO & NO2)

      • All Fossil Fuel combustion (gas esp.) | O3 | photochemical smog | acid precipitation

    • CO (Carbon Monoxide)

      • Incomplete combustion | O3 | Lethal to humans

    • PM (Particulate Matter)

      • Fossil Fuel/Biomass combution | respiration irritation | smog

    • O3 (Ozone; tropospheric)

      • Photochemical oxidation of NO2 | respiration iritation | smog | plant damage

    • Pb (Lead)

      • Metal plants, waster incineration, neurotoxicant

Air Pollutants vs. Greenhouse Gasses

  • CO2 is NOT one of 6 criteria pollutants in Clearn Air Act (although 07’ SC ruling found EPA could regulate greenhouse gases and it began doing so in 09’}

    • Carbon dioxide does not directly lower air quality from a human health standpoint

      • Not toxic to organisms to breath

      • Not damaging to lungs/eyes

      • Does nto lead to smog, decreased cisibility

    • Carbon dioxide is a greenhouse gas; it does lead to earth warming, and thus environmental and human health consequences (bases for SC ruling in 07’)

  • Bottom Line: in APES, carbon dioxide has not typically been included on FRQ scoring guides as an air pollutant

    • (stick to sure fire air pollutants on FRQS: Sulfur Dioxide, Nitrogen Oxides, Ozone, Particulate Matter)

Coal Combustion

  • Releases more air pollutants than other Fossil Fuels; ~35% of global electricity

    • Releases Carbon Monoxide, Carbon Dioxide, Sulfur Dioxide, Nitrogen Oxides, toxic metals (mercury,a rsenic, lead), and Particulate Matter (offten carries the toxic metals)

      • Impacts of Sulfur Dioxide

        • Respiratory irritant (inflammation of bronchioles, lungs), worsens asthma & bronchitis

        • Sulfur aerosols (suspended sulfate particles) block incoming sun, reducing visibility & photosynthesis

        • Forms sulfurous (grey) smog

        • Combines with water & Oxygen in atmosphere to form sulfuric acid → acid precipitation

Nitrogen Oxides (NOx)

  • Released by combustion of anything, especially Fossl Fuels & biomass

    • NOx refers to nitrogen oxides (both NO, and NO2)

      • NO forms when N2 combines with Oxygen (especially during combustion)

      • NO can become NO2 by reacting with Ozone or Oxygen

      • Sunlight converts NO2 back into NO

  • Environmental & human Health Impacts

    • Respiratory irritant

    • Leads to tropospheric ozone (O3) formation, which leads to photochemical smog

    • Combines with water & O2 in atmospheric to form nitric acid → acid precipitation

EPA & Lead

  • Before Clean Air Act, lead was a common gasoline additive; EPA began phasout of lead from gasoline in 1974

    • Vehicles made after 1974 are required to have catalytic converters to reduce Nitrogen Oxides, Carbon Monoxide and hydrocarbon emissions (lead damages catalytic converters)

      • Also a known neutroxicant (damages nervous systems of humans)

Primary vs. Secondary Air Pollutants

  • Primary

    • Emitted directly from sources as vehicles, power plants, factories, or natural sources (volcanoes, forest fires)

    • Nitrogen Oxides, Carbon Monoxide, Carbon Dioxide, Voltaile Organic Compounds, Sulfur Dioxide, Particulate Matter, hydrocarbons

  • Secondary

    • Primary pollutants that have transformed in presence of sunlight, water, Oxygen

    • Occur more during the day (since sunlight often drives formation)

    • Tropospheric O3 (Ozone)

    • Sulfuric Acid (H2SO4) & Sulfate (SO4 2-)

    • Nitric acid (NHO3) & nitrate (NO3 -)

Topic 7.2 (Photochemical Smog)

Photochemical Smog Precursors & Conditions

  • Precursors

    • Nitrogen Dioxide

      • Broken by sunlight into NO + O (free O + O2 → O3)

    • Volatile organic compounds

      • (Hydrocarbons) that bind with NO & form photochemicals oxidants

        • Carbon-based compounds that volatilize (evaporate) easily (this makes them “smelly”)

        • Sources: gasoline, formaldehyde, cleanings fluids, oil-based paints, even coniferous trees (pine smell)

    • Ozone

      • Forms when Nitrogen Dioxide is broken by sunlight & free O binds to Oxygen

        • Respiratory irritation in troposphere ( at earth’s surface )

        • Damaging to plant stomata, limiting growth

  • Conditions

    • Sunlight

      • Drives Ozone formation by breaking down Nitrogen Dioxide → Nitric Oxide + O; then free O atom binds with Oxygen

    • Warmth

      • Hotter atmopshere temperature speeds Ozone formation, evaporation of volatile organic compounds & thus amog formation

Normal Ozone Formation

  • Sunlight breaks Nitrogen Dioxide into Nitric Oxide + O

  • O bonds with O2 to form Ozone

  • At night, Ozone reacts with Nitric Oxide to form Nitrogen Dioxide and O2 once again; Ozone levels drop overnight

  • Ozone formation typically peaks in afternoon when sunlight is most direct and Nitrogen Dioxide emissions from morning traffic have peaked

  • Morning commute leads to high Nitrogen Dioxide levels from car exhaust

Photochemical Smog Formation

  • Sunlight breaks Nitrogen Dioxide into Nitric Oxide + Oxygen

  • Oxygen bonds with Oxygen Gas to form Ozone

  • Without Nitric Oxide to react with, Ozone builds up instead of returning to Oxygen gas & Nitrogen Dioxide overnight

  • Ozone combines with photochemical oxidants (Nitric Oxide + Volatile Organic Compounds) to form photochemical smog

  • Volatile Organic Compounds bon with Nitric Oxde to form photochemical oxidants

Factors that Increase Smog Formation

  • More sunlight (summer, afternoon) = more Ozone

  • Warmer temperature, speeds evaporation of Volatile Organic Compounds that lead to Ozone

  • Higher Volatile Organic Compound emission (gas stations, laundromats, petrochemical & plastic factories)

  • Increased vehicle traffic; increases Nitrogen Dioxide emissions & therefore Ozone formation

  • Urban areas have more smog due to all of these factors

    • More traffic → more Nitrogen Dioxide

    • Hotter temperatures due to low albedo of blacktop

    • More Volatile Organic Compounds due to gas stations & factories

    • More electricity demand; more Nitrogen Oxide emissions from nearby power plants

Impacts & Reduction of Smog

  • Impacts:

    • Environmental

      • Reduces sunlight; limiting photosynthesis

      • Ozone damages plant stomata and irritates animal respiratory tracts

    • Humans

      • Respiratory irritant; worsens asthma, bronchitis, COPD; irritates eyes

    • Economic

      • Increased health care costs to treat asthma, bronchitis, COPD

      • Lost productivity due to sick workers missing work or dying

      • Decreased agricultural tields due to less sunlight reaching crops & damage to plant stomata

  • Reduction:

    • Vehicles

      • Decreasing the number of vehicles on the road decreases Nitrogen Dioxide emissions

      • Fewer vehicles = less gas = fewer Volatile Organic Compounds

        • Carpooling, public transport, bikin, walking, working from home

    • Energy

      • Increased electricity production from renewable sources that don’t emit Nitrogen Oxides (solar, wind, hydro)

      • Natural gas power plants release less Nitrogen Oxides than coal

Sample Questions for this Topic

  • MCQs:

    1. Scientists have discovered that Volatile Organic Compounds (VOCs) emitted from trees can contribute to photochemical smog formation. Data in the table velow were collected in 2006 and 2014 in Berlin, Germany. Isoprene is a VOC released by some tree species. Impact factor refers to the percentage of ozone.

      a. Which of the following best describes the relationship between variables in the data table?

      A) Impact factor causes a change in temperature maximum

      B) Isoprene levels vary depending on traffic and urbanization

      C) Ozone Maximum is correlated to average and maximum temperature

      D) Changes in average temperature are linked to changes in land use in Berlin

      b. Which of the following claims is best supported by the data shown in the table?

      A) Ozone levels are not a serious air quality concern in Berlin

      B) Ozone levels in Berlin were consistently higher in 2014 than in 2006.

      C) Isoprene’s contribution to ozone levels in Berlin was greatest in July of both years

      D) Isoprene levels were negatively correlated with maximum temperature

    2. Air pollution from a power plant is being monitored for levels of nitrogen dioxide and ground-level ozone. The levels are measured daily at the same time. Which of the following best predicts the impact of a dark and cloudy day on the readings for the levels of air pollutants measured?

      A) There will be no change in the levels of nitrogen dioxide or ground-level ozone

      B) There will be a decrease in the level of nitrogen dioxide and an increase in the level of ground-level ozone

      C) There will be an increase in the levels of both nitrogen dioxide and ground-level ozone

      D) There will be an increase in the level of nitrogen dioxide and a decrease in the level of ground-level ozone

    3. The graph shows the average distance traveled by individuals in a population in an urban area in the southwestern United States. Based on the data, which of the following months most likely experiences the highest levels of photochemical smog?

      A) July

      B) August

      C) November

      D) December

  • FRQs:

    1. Explain the relationship between NO2 concentration and ozone concentration represented in this graph.

    1. Describe how the time of day impacts ozone formation

Topic 7.3 (Thermal Inversion)

Urban Heat Island Effect

  • Urban Heat Island Effect

    • Urban areas tend to have higher surface & air temperature than surrounding suburban and rural areas due to:

      • Lower albedo; concrete & asphalt absorb more of sun’s energy than areas with more vegetation (absorbed sunlight given off as IR radiation - heat)

      • Less evapotrasnpiration; water evaporating from surfaces and transpiration from plants carries heat from surface into the atmosphere

        • This cools off rural & suburban areas which have more vegetation

Thermal Inversion

  • Because cold air at the surface is trapped beneath the warmer mass above, convection doesn’t cary pollutants up & away

  • Normally, the atmosphere is warmest at earth’s surface, and cools as altitude rises

  • During a thermal inversion, a cooler air mass becomes trapped near earth’s surface (inverting normal gradient)

    • Due to a warm front moving in over it

    • Or due to hot urban surfaces cooling overnight while IR radiation absorbed during the day is still being released

  • Because warm air rises, air convection carries air pollutants away from earth’s surface & distributes them higher into the atmosphere

Effects of Thermal Inversion

  • Air pollutants (smog, Particulate Matter, Sulfur Dioxide, Nitrogen Oxides) trapped closer to earth

  • Respiratory Irritation: asthma flare ups leading to hospitalization, worsened COPD, emphysema

  • Decreased tourism revenue

  • Decreased photosynthetic rate

Sample Questions for This Topic

  • MCQs:

    1. Which of the following best describse the process shown in the diagram below?

      A) Less-dense, cool air rises up and mixes with the denser warm air above it, increasing the amount of thermal pollution in the atmosphere

      B) Less-dense, warm air creates a temperature inversion

Topic 7.5 (Indoor Air Pollutants)

Developing vs. Developed Countries

  • Developing nations use more subsitence fuels such as wood, manure, charcoal (biomass)

    • These biomass fuels release Carbon Monoxide, Particulate Matter, Nitrogen Oxides, Volatile Organic Compounds (can also cause deforestation)

    • Often combusted indoors with poor ventilation, leading to high concentrations

    • Estimated 3 billion people globally cook with subsitence fuels, resulting in estimated 3.5-4.3 million deaths annually

  • Developed nations use more commerical fuels (coal, oil, natural gas) supplied by utilities

    • Typically burned in clsoed, well ventilated furnances, stoves, etc.

  • Major indoor air pollutants in developed nations come from chemicals in products: adhesives in furniture, cleaning supplies, insulation, lead paint

PM & Asbestos

  • Particulates (PM) are a common indoor air pollutant

    • Example: smoke (from indoor biomass combustion or cigarettes), dust, and asbestos

  • Asbestos is a long, silicate particle previously used in insulation (since been linked to lung cancer & asbestosis)

    • Phased out of use, but still remains in older buildings

      • Not dangerous until insulation is disturbed and asbestos particles enter air & then respiratory tract

      • Should be removed by trained professionals which proper respiratory equipment, ventilation in the area it’s being removed from, plastic to seal off area from rest of the building

CO (Carbon Monoxide)

  • Carbon Monoxide is produced by incomplete combustion of basically any fuel

    • Not all the fuel is combusted eu to low Oxygen or temperature

  • Carbon Monoxide is an asphyxiant: causes suffocation due to Carbon Monoxide binding to hemoglobin in blood, displacing Oxygen

    • Lethal to humans in high concentrations, especially with poor ventilation (odorless and colorless - hard to detect)

      • Developed nations: Carbon Monoxide released into home by malfunctioning natural gas furnance ventilation

        • Can be detected by carbon monoxide detectors (similar to smoke detectors)

      • Developing nations: Carbon Monoxide emitted from indoor biomass combustion for heating/cooking

VOCs (Volatile Organic Compounds)

  • Chemicals used in variety of home products that easily vaporize, enter air, ad irritate eyes, lungs, bronchioles

    • Adhesives/sealants: chemicals used to glue carpet down, hold furniture together, seal panels

      • Formaldehyde is a common adhesive in particle board and carpet glues (new carpet smell)

    • Cleaners: common household cleaners and deodorizers such as febreeze

    • Plastics and Fabrics: both can release Volatile Organic Compounds themselves, or form adhesives used in production

Radon Gas

  • Radioactive gas released by decay or uranium naturally found in rocks underground (granite especially)

    • Usually enters homes through cracks in the foundatuion & then dispenses up from basement/foundation through home

      • Can also seep into groundwater sources & enter body through drinking water

    • 2nd leading cause of lung cancer after smoking

      • EPA recommends testing homes with airborne Radon monitor

      • Sealing cracks in foundation can prevent it from entering and increasing ventilation in the home can disperse it if it’s detected

Topic 7.6 (Reduction of Air Pollutants)

Reducing Emissions

  • Reducing emissions = reducing air pollutants

    • Drive less, walk/bike/bus more

    • Conserve electricity (smart appliances)

    • Eat more plants, less meat

    • Renewable, non-pollution emitting energy (solar, wind, hydro)

Laws/Regulations

  • Clean Air Act

    • Allows EPA to set acceptable levels for criteria air pollutants

      • Monitor emissions levels from power plants and other facilities

      • Tax/sue/fine coporations that release emissions above levels

  • Pollution Credits

    • Similar to Individual Transfer Quota for fish

    • Companies that reduce emissions well below EPA-set levels earn pollution credits

      • They can sell these to companies that release more than acceptable levels

  • CAFE Vehicle Standards

    • (Coportate Average Fuel Economy) standards require the entire US “fleet” of vehicles

    • More efficient vehicles burn less gasoline and release less Nitrogen Oxides, Particulate Matter, Carbon Monoxide, and Carbon Dioxide

Reducing Vehicle Air Pollutants

  • Vapor Recovery Nozzle

    • Capture hydrocarbon Volatile Organic Compounds released from gasloine fumes during refueling

      • Separate tube inside nozzle captures vapors & returns them to underground storage tank beneath the gas station

      • Reduces Volatile Organic Compounds, which contribute to smog & irritate respiraritory tracts

      • Also reduces benzene (carcinogen) released from gasoline vapors

  • Catalytic Converter (CC)

    • Required on all vehicles after 1975

    • Contains metals (platinum & palladum) that bind to Nitrogen Oxides and Carbon Monoxide

      • Catalytic Converter converts Nitrogen Oxides, Carbon Monoxide, and other hydrocarbons into Carbon Dioxide, Nitrogen Gas, Oxygen Gas, and Water

Reducing Sulfur Oxides & Nitrogen Oxides

  • Crushed Limestone (Sulfur Dioxide)

    • Used to reduce Sulfur Dioxide from coal power plants

      • Crushed coal mixed with limestone (calcium carbonate) before being burned in boiler

      • Calcium carbonate in limestone combines with Sulfur Dioxide to produce calcium sulfate, reducing the Sulfer Dioxide being emitted

      • Calcium sulfate can be used to make gypsum wallboard or sheetrock for home foundations

Topic 7.7 (Acid Rain)

Sources of Nitrogen Oxides & Sulfur Dioxide

  • Nitrogen Oxides and Sulfur Dioxide are the primary pollutants that cause most acid precipitation

    • Major Sources

      • Sulfur Dioxide: coal fired power plants, metal factories, vehicles that burn diesel fuel

      • Nitrogen Oxides: vehicle emissions, disel generators coal power plants

    • Limiting Acid Rain

      • Reducing Nitrogen Oxides & Sulfur Dioxide emissions reduces acid deposition

        • Higher CAFE Standards

        • More public transit

        • Renewable energy sources

        • More efficient electricity use

      • Since passage of Clean Air Act, acid deposition has decreased significantly

  • Nitrogen Oxides and Sulfur Dioxide react with Oxygen Gas and Water in the atmosphere, forming nitric and sulfuric acid

  • Sulfuric acid and nitric acid dissociate in the presenof water into sulfate and nitrate ions, and hydrogen ions (H+)

  • Acidic rain water (higher hydrogen ions concentration) decreases soil and water pH; can limit tree growth in forests down wind from major Sulfur Dioxide & Nitrogen Oxides sources

Enironmental Effects of Acid Rain

  • Acidity = higher hydrogen ions concentration, lower pH

  • Soil/Water Acidification

    • Hydrogen Ions displace or leech other positive charged nutrients (Calcium Ions, Potassium Ions) from soil

    • Hydrogen Ions also make toxic metals like aluminum and mercury more soluble in soil and water

      • This can slow growth or kill plants and animals living in the soil or water

  • Aquatic species have different pH tolerances

  • pH Tolerance

    • As pH decreases (more acidic) outside optimal range for a species, population declines

      • When pH leaves range of tolerance, they cannot survive at all, due to:

        • Aluminum toxicity

        • Disrupted blood osmolarity (Sodium Ions/Chloride balance disrupted at low pH)

    • Indicator species can be surveryed and used to determine conditions of an ecosystem (soil, water, etc.)

      • Example: high whitemoss/filamentous algae population pH < 6.0

      • High crustacean population indicates pH > 6.0

Mitigating Acid Rain

  • Limestone (calcium carbonate) is a natural base that can neutralize acidic soil/water

  • Decreasing these primary pollutants that drive acid rain can reduce it

    • Renewable energy sources, decreasing coal comb.

    • Fluidized bed combustion & lower burning temp. for existing coal power plants

    • Dry or wet scrubbers

UNIT 8

Topic 8.1 (Sources of Pollutants)

Point vs, Nonpoint Pollutant Sources

  • Point Source

    • Pollutant that enters environment from an easily identified and confied place (You can point to it)

  • Nonpoint Source

    • Pollutants entering the environment from many places at once (Difficult to point to one inidividual source)

Must-Know Pollutation Examples

  • Point Source

    • Animal waste runoff from a concentrated animal feeding operation (ammonia, fecal coliform bacteria)

    • Emissions from smokestack of a coal power plant (Carbon DIoxide, Nitrogen Oxides, Sulfur Dioxide, Particulate Matter)

    • BP Oil SPill (hydrocarbons, benzene)

  • Nonpoint Source

    • Urban runoff (motor oil, nitrate fertilizer, road salt, sediment)

    • Pesticides sprayed on agricultural fields; carried by wind and washed off large agricultural regions into bodies of water

  • Estuaries and bays are polluted by many nonpoint pollution sources from the large watersheds that empty into them.

Pollutants vs. Pollution

  • Pollutants

    • Specific chemicals or groups of chemicals from specific sources with specific environmental & human health effects

      • Much more likely to earn you FRQ credit

        • On any pollution-related FRQ:

          • Their sources

          • The environmental & human effects

          • Their mitigation strategies

  • Pollution

    • Vage, nondescript term for any substance that is harmful to the environment

      • Never acceptable on an APES FRQ

        • Exceptions:

          • Specifies categories of pollution

            • Thermal pollution

            • Noise pollution

            • Sediment pollution

Topic 8.2 (Human Impacts on Ecosystems)

Range of Tolerance

  • Organisms have range of tolerance for abiotic conditions in their habitat

    • pH, temperature, salinity (saltiness), sunlight, nutrient levels (ammonia, phosphate)

      • Organisms also have range of tolerance for pollutants that human activies release into their habitats

        • Pollutants cause physiological stress such as

          • Limited growth

          • Limited reproductive function

          • Difficulty respiring (breathing), potentially asphyxiation (suffocation)

          • Hormonal disruption

          • Death (if concentration of pollutant is high enough)

  • A big theme of Unit 8 is being able to explain specific effects of pollutants on organisms

Enironmental Effects of Acid Rain

  • Aquatic species have different pH tolerances

  • pH Tolerance

    • As pH decreases (more acidic) outside optimal range for a species, population declines

      • When pH leaves range of tolerance, they cannot survive at all, due to:

        • Aluminum toxicity

        • Disrupted blood osmolarity (Sodium Ions/Chloride balance disrupted at low pH)

    • Indicator species can be surveryed and used to determine conditions of an ecosystem (soil, water, etc.)

      • Example: high whitemoss/filamentous algae population pH < 6.0

      • High crustacean population indicates pH > 6.0

Temperature Tolerance of Reef Algae

  • Coral reef = mutualistic relationship between coral & photsynthetic algae called zooxanthellae; algae supply sugar & coral supply CO2 + detritus (nutrient containing organic matter)

    • Algae have narrow temperature tolerance and leave the reef when temperature rises

      • Pollutants from runoff (sediment, pesticides, sunscreen) can also force algae from reef

    • Coral lose color & become stressed and vulnerable to disease without algae (main food source)

Human Impacts on Coral Reef

  • Humans disrupt coral reef ecosystems via green house gas emissions (warming ocean temperatuer & bleaching coral)

    • Overfishing decreases fish populations in coral reef ecosystem & bottom trawling can break reef structure and stir up sediment

      • Urban and agricultural runoff also damages coral reef ecosystems

        • Sediment pollution: sediment carried into ocean by runoff makes coral reef waters more turbid, reducing sunlight (photosynthesis)

        • Toxicants: chemicals in sunscreen, oil from roadways, pesticides from agricultural runoff

        • Nutrients (Phosphorus/Nitrogen): ammonia from animal waste, nitrates/phosphates from agriculture or lawn fertilizers

Oil Spill Effects

  • Hydrocarbons in crude oil (petroluem) are toxic to many marine organisms and can kill them, especialy if they ingest (eat) the oil or absorb through gills/skin

    • Other physiological effects:

      • Decreased visibility and decreased photosynthesis due to less sunlight penetrating water urface

      • Oil sticking to bird feathers

      • Oil sinking to bottom and killing bottom-dwellers due to: direct toxicity or suffocation

  • Oil can wash ashore and decrease tourism revenue and kill fish, decreasing fishing indsutry revenue, hurt restaurants that severe fish

    • Oil can settle deep in oot structures of estuary habitats like mangroves or salt marshes

      • Can be toxic to salt marsh grasses, killing them and loosening their root structure, leading to coastline erosion

        • Can remove habitats used by fish & shellfish for breeding grounds

Oil Spill Clean Up

  • Oil spills can occur when an underwater oil well explodes/blows out (BP Gulf Spill) or when a tanker runs into a rock/iceburg and is punctured (Exdon Valdez)

    • Cleanup can involve vooms on surface to contain spread and ships with vaccuum tubes to sipgon oil off of the surface or devices to skim it off

    • Physical removal of oil from beach sand and rocks with towels, soaps, shovels

    • Chemical dispersants sprayed on oil slicks to break up and sink to the bottom

      • Clears up surface, but can smother bottom-dwellers

      • Dispersant chemicals may be harmful

    • Burning oil off surface

Topic 8.3 (Endocrine Disruptors & Industrial Water Pollutants)

Endocrine Disruptors

  • Chemicals that interfere with the endrocrine (hormonal) systems of animals

    • Bind to cellular receptors meant for hormones, blocking the hormone from being received, or amplifying its effects

      • Human medications that pass through urine & into seweage or are flushed down toilet are a common source (meant to influence human hormones, so they can also disrupt animals)

        • Example: Atrazine (herbicide) binds to receptors of cells that should convert estrogen into testosterone in mal frogs, leading to: high estrogen in males, low spemer count, even feminzation (development of eggs in the testes or ovary formation)

  • Atrazine: broad-spectrum herbicide used to control weeds & prevent crop loss

    • Applied to agricultural fields, runs off into local surface or groundwater or is carried by wind

    • Can contaminate human well-water, or enter body via unwashed produce

  • DDT: broad-spectrum insecticide that was phased out, but still persists in environment

    • Applied to agricultural fields, runs off into local surface or groundwater or is carried by wind

  • Phthalates: compounds used in plastic and cosmetic manufacturing

    • Enter surface & groundwater via intentional dumping of trash, or chemical waste from plastic/cosmetic factories improperly disposing of water, landfill leaching

    • Also found in some cosmetics & plastic food containers (#3 plastic & “fragrance”)

  • Lead, arsenic, mercury: heavy metals

  • Many human medications that enter sewafe via human urine or flushed meds

Mercury

  • Mercury: naturally occuring in coal, released by anthropogenic activities:

    • Coal combustion, trash inceneration, burning medical waste, heating limestone for cement

      • Attaches to Particulate Matter released by burning * deposists in soil/water whereever Particulate Matter settles

      • Can be released if coal ash stored in ponds overflow & runoff

    • Endocrine Disruptor: inhibits estrogen & insulin (intereferes with menstrual cycle & ovulation)

    • Tertogen: (chemical harmful to developing fetuses) can accumulate in fetus brain

      • Pregnant women can reduce risk by eating less seafood

  • Mercury itself isn’t toxic, but bacteria in water sources convert it to methylmercury which is highly toxic to animals (neurotoxicant that damages central nervous system)

Arsenic & Lead

  • Arsenic: naturally occuring element in rocks underground that can dissolve into drinking water; natural release into groundwater can be worsened by mining

    • Anthropogenic sources: formerly in pesticides applied to agricultural fields (can still linger in soil, wood treatment chemical to prevent rot, coal combustion & ash)

      • Carcinogenic (lungs, bladder, kidneys) & endrocrine disrupting

      • Endocrine disruptor (specifically glucocorticoid system)

        • Can be removed with water filters

  • Lead: found in old paint (in homes), old water pipes, and soils contaminated by Particulate Matter from behicle exhaust before lead was phased out of gas in 70s

    • Also released in fly ash (Particulate Matter) of coal combustion

      • Neurotoxicant (damages central nervous system, especially in children)

      • Endocrine disruptor

        • Can be removed with water filters

Coal Ash

  • Coal ash can be a source of mercury, lead, and arsenic

    • Can attach to fly ash (Particulate Matter) from smokestack and be carried by wind, deposited in ecosystems far away

    • Both fly and bottom coal ash are often stored on site in ponds, dug into soil & lined with plastic (sometimes)

      • Ponds can leach into groundwater, contaminating it with arsenic, lead, mercury,

      • Ponds can overflow & runoff into nearby surface waters & agricultural fields

Topic 8.4 (Human Impacts on Wetlands and Mangroves)

Wetlands

  • An area with soil submerged/saturated in water for at least part of the year, but shallow enough for emergent plants

    • Wetland plants have adapted to living with roots submerged in standing water (cottails, lily pads, reeds(

  • Ecosystem Services of Wetlands

    • Provisioning: habitat for animal & plant foods

    • Regulating: groundwater rechartge, absorbing of floodwater, CO2, sequestration

    • Supporting: H2O filtration, pollinator habitats, nutrient cycling, pest control

    • Cultural: tourism revenue, fishing licesne, camping fees, ed/med research

Threats to Wetlands

  • Pollutants: nutrients (Nitrogen/Phosphorus), sediment, motor oilm pesticides, endocrine disruptors

  • Development: wetlands cna be fillied in or drained to be developed int homes, parking lots, stores, or agricultural land

    • Water diversion upstream for flood control, agriculture, or drinking water can reduce water flow and dry up wetlands

      • Dam construction for flood control/hydroelectricity reduces water & sediment (Nitrogen/Phosphorus) flow to wetlands

    • Overfishing: disrupts food web of wetlands (decrease in fish predators, increase in prey)

Topic 8.5 (Eutrophication)

Eutrophication Process

  • Because they’re limiting nutrients in aquatic ecosystems, extra input of Nitrogen & Phosphorus lead to eutrophication (excess nutrients) which fuels algae growth

    • Algae bloom coers surface of water, blocking sunlight & killing plants below surface

    • Algae eventually die-off; bacteria that break dwn dead algae use up Oxygen Gas in he water (because decomposition = aerobic process)

    • Lower Oxygen Gas levels (dissolved oxygen) in water kills awauatic animals, especially fish

    • Bacteria use up even more Oxygen Gas to decompose dead aquatic animals

    • Creates positive feedback loop: less Oxygen Gas → more dead organisms → more bacterial decomposition → less Oxygen Gas

Cultural Eutrophication

  • Antrhopogenic nutrient pollution (Nitrogen & Phosphorus) that leads to eutrophication

    • Algae bloom due to increase of Nitrogen/Phosphorus → decreased sunlight → plants below surface die → bacteria use up Oxygen Gas for decomposition → hypoxia (low Oxygen Gas) & dead zones

  • Major Nitrogen/Phosphorus sources:

    1. Discharge from sewage treatment plants (Nitrogen/Phosphorus in human waste & phosphates in soaps/detergents)

    2. Animal waste from Concentrated Animal Feeding Operations

    3. Synthetic fertilizer from agricultural fields & lawns

Oligotrophic Waterways

  • Waterways with low nutrient (Nitrogen/Phosphorus) levels, stable algae population, and high dissolved oxygen

    • Can be de to lack of nutrient pollution, or age of the body of water

    • Aquatic ecosystems naturally undergo succession

      • Sediment buildup on bottom (benthic zone) leads to higher nutrient levels

      • Overtime, ponds naturally shift from oligotrophic, to mesotrophic, to eutrophic

Dissolved Oxygen & Dead Zones

  • Decrease in dissolved oxygen (hypoxia) is what causes a dead zone

    • All aquatic life requires dissolved oxygen in water for respiration

    • As Dissolved Oxygen decreases, fewer species can be supported

      • Most fish require at least 3.0 ppm to survive, 6.0 ppm to reproduce

Topic 8.6 (Thermal Pollution)

Solubility of Oxygen & Temperature

  • Solubility = the ability of solid/liquid/gas to dissolve into a liquid (oxygen dissolving into water in this case)

    • Inverse relationship between water temperature & oxygen solubility

      • As water temperature increases, Dissolved Oxygen decreases

    • Thermal Pollution: when heat released into water has negative effectson organisms living in the water

      • Heat increases respiration rate of aquatic organisms (thermal shock)

      • Hot water also has less Oxygen Gas

        • This can lead to suffocation without enough Oxygen Gas to support respiration

Sources of Thermal Pollution

  • Power plants use cool water from surface/ground water sources nearby to cool steam used to turn a turbine back into water to resuse

    • Steel mills, paper mills, and other manufacturing plants also use cool water to cool down machinery & returned warm water to local surface waters

    • Urban stormwater runoff can also case thermal pollution due to heat from blacktop/asphalt

  • Nuclear power plants require especially large amounts of cool water to cool stream back into water & to cool the reactor core

Cooling Towers

  • Cooling towers/ponds are used to cool seam back into water & to hold warmed water before returning to local surface water

    • Already standard in nuclear power plants, but can be optimized to cool water better or hold it longer before returning to nearby surface waters

Topic 8.7 (Persistant Organic Pollutants)

POPs

  • Persistent (long-lasting) Organic (carbon-based) Pollutants

    • Synthetic (human-made) compounds that do not easily breakdown in the environment; accumulate and buildup in water & soil

      • Fat-soluble, meaning they also accumulate and persist in animals’ fat tissue instead of passing through the body (don’t easily dissolve into blood/urine)

Examples & Sources of POPs

  • Examples:

    • DDT (outdated insecticide)

    • PCBs (plast/plant additive)

    • PBDEs (fire-proofing)

    • BPA (plastic additive)

    • Dioxins (fertilizer production & combustion of waste & biomass)

    • Phthalates (plastics)

    • Perchlorates (rocket.missile fuel, fireworks)

  • Pesticides

    • DDT was widely used as an insecticide before phaseout in most developed nations

    • Still persists in soils & sediments in aquatic ecosystems and builds up in food webs

  • Medications (Pharmaceutical Compounds)

    • Steroids, reproductive hormones, antibiotics, that pass through human bodies & into sewage release from treatment plants

    • Persists in streams/rivers & disrupt aquatic organisms’ endocrine function

  • Dioxins

    • Byproduct of fertilizer production & burning of medicla waste, Fossil Fuels, biomass

    • 90% of human dioxin exposure comes from animal fats (meat, dairy, fish) since dioxins buildup in animal fat tissue

Examples & Transport of POPs

  • PCBs

    • Additives in paint and plastics, released into aquatic ecosystem by industrial wastewater

    • Toxic to fish, causing spawning failure and endocrine disruption

    • Reproductive failure & cancer in humans

      • Human exposure comes through animal products

  • Perchlorates

    • Given off by rockets, missiles, and fireworks

    • Especially common near military testing sites or rocket launch pods

    • Remain in soil and can leach into groundwater or runoff into surface waters

  • Persistant Organic Pollutants travel long distances through wind & water, impacting ecosystems far away

    • Wasterwater release from industrial processes, leachate from landfills or improperly buried industrial waste, fertilizer/pesticide production, emissions from burning waste/biomass

    • Enter soil/water eaten by animals, stored in fat, eaten by humans or taken in via drinking water

Topic 8.8 (Biomagnification)

Bioaccumulation

  • Absorption and concentration of compounds (especially fat-soluble ones like Persistant Organic Pollutants) in cells & fat tissues of organisms

    • Because fat-soluble compounds like Persistant Organic Pollutants and methylmercury don’t issolve easily in water, they don’t enter blood easily & don’t leave body in urine easily

      • Instead they build up in fat tissue

      • This leads to them building up to reach higher and higher concentrations in the organism over time

Biomagnification

  • Increasing concentrations of fat-soluble compounds like methylmercury and Persistant Organic Pollutants in each level up the trophic pyramid or food web/chain

    • Biomagnification begins with Persistant Organic Pollutants or methylmercury in sediments or plants in an ecosystem (phytoplankton, grass)

      • Primary consumers (zooplankton, bottom feeding fish, insects) take in Persistant Organic Pollutants by eating producers, casuing bioaccumulation of Persistant Organic Pollutants in their tissues

      • Secondary consumers eat primary consumers and take in the Persistant Organic Pollutants in their tissues

        • Because of the 10% rule, organisms at each successive trophic level need to eat more and more biomass to recieve enough energy, leading to higher and higher Persistant Organic Pollutant levels over their lifetimes

        • Large predators like salmon, dolphins, and whales have highest Persistant Organic Pollutant/methylmercury levels

Biomagnification (DDT)

  • DDT was banned in many developed nations, but still persists in sediments of many bodies of water

    • Taken in by bottom feeders/zooplankton & biomagnified at higher trophic levels

    • Reach highest levels in top predators, especially predatory birds like eagles & osprey

      • Causes thinning of the eggshells in these birds

      • Linked to massive population decline of bald eagle in United States, which prompted passage of Endangered Species Act (1973)

Biomagnification (methylmercury)

  • Mercury is emitted from burning coal & by volcanoes, carried by wind, and deposited in water where bacteria convert it into toxic methylmercury

    • Taken in by phytoplankton & biomagnified at higher trophic levels

    • Reach highest levels in top predators, tune, sharks, whales

      • Neurotoxicant: damages the central nervous system of animals

    • Human exposure to methylmercury & Persistant Organic Pollutants comes from eating large predatory fish like tuna & salmon (and other seafood)

      • Damage to human nervous system (especially deeloping fetus) and disrupt reproductive system

Topic 8.9 (Solid Waste Disposal)

Solid Waste Types & Sources

  • Municipal Solid Waste

    • Solid waste from cities (houselands, businesses, schools, etc.)

    • Waste “stream” refers to flow of solid waste to recycling centers, landfills, or trah incineration (burning) facilities

    • Also known as trash, litter, garbage

  • E-Waste

    • Old computers, TVs, phones, tablets

    • Only ~2% of Municipal Solid Waste; considered hazardous waste due to metals like cadmium, lead, mecury, and PBDEs (fireproof chemicals)

    • Can leach endocrine disrupting chemicals out of landfills if thrown away with regular Municipal Solid Waste (should be disposed of at special facilities that recycle parts)

Sanitary Lanfills

  • APES lingo for “landfills” or where developed nations dispose of trash; different thant “dumps” which are just areas where trash is dumped, without the features below

    • Clay/plastic bottom liner: layer of clay/plastic on the bottom of a hole in the ground; prevents pollutants from leaking out into soil/groundwater

    • Leachate Collection System: System of tubes/pipes at bottom to collect leachate (water draining through waste & carrying pollutants) for treatment & disposal

    • Methan Recovery System: System of tubes/pipes to collect that methane produced by anaerobic decomposition in the landfill

      • Methane can be used to generate electricity or heat buildings

    • Clay Cap: Clay-soil mixture used to cover the landfill once it’s full; keeps out animals, keeps in smell, and allows vegetation to regrow

Landfills Contents & Decomposition

  • Landfills generally ahve very low rates of decomposition due to low Oxygen Gas, moisture, and organic material combination

    • Since these 3 factors are rarely present together in landfills, little decomposition occurs and landfills typically remain about the same size as when they were filled

  • Things that should NOT be landfilled:

    • Hazardous waste (antifreeze, motor oil, cleaners, electronics, car batteries)

    • Metals like copper & aluminum (should be recycled)

    • Old tires; often left in large piles that hold standing water ideal for mosquito breeding

  • Things that SHOULD be landfilled:

    • Cardboard/food wrappers that have too much foo resiude & can’t be recycled

    • Rubber, plastic films/wraps

    • Sytrofoam

      • Food, yard waste, and paper can and do go in landfills, but should be recycled or composted

Landfill Issues

  • Landfills have environmental impacts like groundwater contamination and release of GHGs

    • Groundwater can be contaminated with heavy metals (lead, merury), acids, medications, and bacteria if leachate leaks through livng into soil/groundwater beneath

    • Greenhouse gases (Carbon Dioxide and Methane) are released from landfills due to decomposition; both contribute to global warming & climate change

  • Not In My Back Yard = idea that communities don’t want landfills near them for a number of reasons

    • Smell & sight

    • Landfills can attract animals (rats, crows)

    • Groundwater contamination concerns

      • Landfills should be located far from river & streams and neighborhoods to avoid water contamination

  • Landfills are often placed near low-income or minority communities that don’t have the resources or political power to fight against these decisions

Waste Incineration & Ocean Dumping

  • Waste can be incinerated (burned) to reduce the volume that needs to be landfilled; since most waste (paper, plastic, food) = hydrogen, carbon, and oxygen, it easily combusts at high temperatures

    • Can reduce volume by 90&, but also releases CO2 and air pollutants (Particulate Matter, Sulfur Oxides, Nitrogen Oxides)

      • Bottom ash may contain toxic metals (lead, mercury, cadmium) & is storied in ash ponds, then taken to special landfills

      • Toxic metals can leach out of storage ponds or be released into atmosphere

  • Can be burned to generate electricity

  • Illegal ocean dumping occurs in some countries with few environmental regulations or lack of enforcement

    • Plastic specially collects into large floating garbage patches in the ocean

    • Can suffocate animals if they ingest (eat) it or entangle them so they can’t fly or swim and may starve

Topic 8.10 (Waste Reduction)

Reduce, Reuse, Recycle

  • The Three Rs

    • Reducing consumption si the msot sustainable because it decreases natural resources harvesting and energy inputs to creating, packaging, and shipping goods

      • Example: metal/reusable water bottle to reduce plastic use

        • Reusing: the next most sustainable because it doesn’t require additional energy to create a product

          • Example: Buying second hand clothes, using old wood pallets for furniture, washing plastic takeout food containers and resuing

    • Recycling: processing and converting solid waste material into new products

      • Example: Glass being turned into glass again (closed-loop), plastic water bottles being turned into fabric for clothes/jackets (open loop)

        • Least sustainable of the three Rs due to the amount of energy it rquires to process and convert waste materials

Recycling Pros and Cons

  • Pros of Recycling

    • Reduces demand for new materials, specially metals and wood which case habitat destruction & soil erosion when harvested

      • Reduces energy required to shiw raw materials and produce new products (fewer Fossil Fuel combustion)

      • Reduces landfill volume, conserving landfill space & reducing need for more landfills

  • Cons of Recycling

    • Recycling is costly and still requires significant energy

      • Cities that offer recycling services need to process, sort, and sell collected materials; prices change rapidly, leading to “recycled” materials often being thrown away

        • When citizens recycle items that shouldn’t be recycled (wrappers with food, styrofoam, etc.) it increases the cost of cities to sort & process'

Composting

  • Organic matter (food scraps, paper, yard waste) being decomposed under controlled conditions

    • Reduces landfill volume and produces rich organic matter that can enhance water holding capacity, nutrient levels of agricultural or garden soil

      • Produces valuable product to sell (compost)

    • Reduces the amount of methane released bu anaerobic decomposition of roganic matter in landfills

    • Should be done with proper mix of “browns” (Carbon) to “greens” (Nitrogen) ~30:1

      • Should also be aerated and mixed to optimize decomposition (bacteria need Oxygen Gas for decomposition)

  • Potential drawbacks include the foul smell that can be produced if not properly rotated & aerated and rodents or other pests that may be attracted

E-Waste

  • Waste from electronics (phones, computers, etc.) that often contain heavy metals (lead, mercury, cadmium)

    • Can leach these toxic metals into soil & groundwater if disposed of in landfills or open dump

  • Can be recycled and reused to create new electronics, but often sent to developing nations for recycling due to health hazards, more strict environment & worker protection laws in developing nations

    • Can be dismantled sold to countries that extract valuable metals (gold, silver, platinum) from motherboards

    • Often burned or dumped to less strict environment regulatitions or lack of enforcement in developing nations

Waste to Energy

  • Waste can be incinerated (burned) to reduce the volume & also egnerate electricity; most waste (paper, plastic, food) = hydrogen, carbon, and oxygen so it easily combusts at high temperatures

    • Same process as burning coal, Natural Gas, biomas

    • Heat → water → steam → turbine → generator → electricity

  • Methane gas produced by decomposition in landfill can be collected with pipes & burned to generate electricity

    • Heat → water → steam → turbine → generator → electricity

    • Reduces landfill volume

    • Produces electricity without fracking or mining for Fossil Fuels

Topic 8.11 (Sewage Treatment)

Water Treatment Process

  • Primary Treatment

    • Physical removal of large debris (TP, leaves, plastic, sediment) with a screen or gate

      • Grit chamber allows sediment (sand, gravel) to settle out & be removed

  • Secondary Treatment

    • Biological breakdown of organic matter (feces) by bacteria; aerobic process that requires Oxygen Gas

      • Oxygen Gas is bubbled into aeration tank filled with bacteria that break down organic matter into Carbon Dioxide and nutrients like Nitrogen & Phosphorus

      • Secondary treatment removes 70% of Phosphorus & 50% of Nitrogen

        • DOES NOT remove Persistant Organic Pollutants such as medications or pesticides

    • After primary & secondary treatment, some plants go directly to disinfectant (UV, ozone, chlorine) & discharge into surface water, while some will use tertiary treatment to remove more nutrients before discharge

  • Tertiary Treatment

    • Ecological or chemical treatments to reduce pollutants left after primary & secondary (Nitrogen, Phosphorus, bacteria)

  • Disinfectant

    • UV light, ozone, or chlorine is used to kill bacteria or other pathogens, such as e. Coli (considered part of tertiary treatment)

  • Effluent: liquid waste (sewage) discharged into a surface body of water, typically from a wasterwater treatment plant

  • Sludge: inorganic, solid waste that collects at the bottom of tanks in primary and secondary treatment

    • Water is spun/pumped to concentrate it further

    • Dry, remaining physical waste is collected to be put in landfill, burned, or turned into fertilizer pellets

Tertiary Treatment

  • Tertiary treatment uses chemical filters to remove more of the nitrates & phosphates from secondary treatment discharge

  • Critical step because effluent that is discharged into surface waters with elevated nitrate/phosphate levels leads to eutrophication

  • Expensive and not always used

Sewage Treatment Issues

  • Combine dsewage and stormwater runoff systems can cause wastewater treatment plants to flood during heavy rains, releasing raw sewage into surface waters

    • Beneficial because it treats stormwater runoof normally, but causes overflow during heavy rains

    • Raw sewage release contaminates surface waters with:

      • E. coli

      • Ammonia

      • Nitrates

      • Phosphates

      • Endocrine disruptors (medications)

  • Even treated wastewater effluent released into surface water often has elevated Nitrogen/Phosphorus levels and endocrine disruptors (medications passed through the body)

Topic 8.12 (LD50)

Dose Reponse Studies & LD50

  • Studies that expose an organism to different doses of concentrations of chemical in order to measure the response (effect) of the organism

  • Independent variable = concentration of the chemical (added to food, water, or air)

  • Dependent variable = reponse measured in organisms (usually death or impairment)

    • LD50 refers to the dose or concentration of the chemical that kills 50% of the population being studied (example arsenic LD50 in mice = 13 mg/kg)

      • LD50 data are usually expressed as:

        • mass (g, mg)/body unit mass (kg)

        • ppm - parts per million (in air)

        • mass/volume (in water of blood)

Topic 8.13 (Dose Response Curve)

Dose Response Curve

  • The data from a dose response study, graphed with percent mortality or other effect on the y-axis and dose concentration of chemical on x-axis

    • Lowest dose where an effect (death, paralysis, cancer) starts to occur is called the threshold or toxicity threshold

    • Dose response curves are usually “S-shaped” - low mortality at low doses, rapid increase in mortality as dose increases, level off near 100% mortality athigh dosage

ED50 & Other Dose Respones

  • ED50 refers to the dose concetration of a toxin or chemical that causes a non-lethal effect (inferility, paralysis, cancer, etc.) in 50% of the population being tested

    • Example: the concentration of atrazine in water that causes 50% of the frogs to become infertile

    • Same general “s-shape” as LD50 dose response curve, but at lower dose concentrations

Dose Response Data & Human Health

  • Dose-response studies for toxic chemical are not done on humans: data from other mammals (mice, rats) are used to simulate human toxicity

  • To determine maximum allowable levels for humans, we generally divide LD50 or ED50 dose concentration by 1,000 for extreme caution

  • Acute vs. Chronic studies: Most dose-response studies are considered acute, since they only measure effects over a short period of time; they’re also isolated to a lab, so they don’t measure ecological effects of organisms dying (trophic cascades)

  • Chronic studies are longer-term and follow developmental impacts

    • Example: study of fish from hatchlings to adults to study sexual maturation

Topic 8.14 (Pollution and Human Health)

Routes of Exposure & Synergism

  • It’s difficult ot establish exactly how toxic differnt pollutants are to humans because we have so many roues of exposure to so many different pollutants, tht studying the effects of just one pollutant is difficult.

    • Routes of Exposure

      • Ways that a pollutant enters the human body

        • Lead → water pipes & paint chips

        • Mercury → seafood (tuna)

        • Carbon Monoxide → indoor biomass combustion

        • Particulate Matter → pollen, dust, etc.

        • Arsenic → rice, groundwater

    • Synergism

      • The interaction of two or more substances to cause an effect great than each of them individually

        • Example: Asthma caused by Particulate Matter from coal PPs and COVID-19 damaging lungs

        • Carcinogenic effect of abestos combined with lung damage from smoking

      • Synergisms make it especially ahrd to pinpoint the exact effects of one specifc pollutant on humans

Dysentery

  • Bacterial infection caused by food or water being contaminated with feces (often from sewage release into rivers & streams used for drinking water)

  • Causes intestinal swelling and can result in blood in feces

    • Results in severe dehydration due to diarrhea (fluid loss)

    • Kills 1.1 million people annually, mostly in developing countries wiht poor sanitationa nd limited access to water filtration

  • Can be treated with antibiotics that kill the bacteria causing the infection and access to treated/filtered water that can rehydrate

Mesothelioma (asbestos)

  • A type of cancerous tumor caused by exposure to asbestos, primarily affecting the lining (epithelium) of the respiratory tract, heart, or abdominal cavity

    • Asbestos exposure comes primarily from old insulation materials used in attics, ceiling and flooring boards; when the insulation becomes physically disturbed, asbestos particles are released into the air & inhaled

    • Removal of asbestos-containing insulation material should be done by professionals with proper training and equipment that protects them from inhaling the asbestos

      • The area where asbestos is removed from should be sealed off from other areas in the building and well-ventilated during the removal process

      • Insulation without asbestos should be used to replace it

Troposhperic Ozone (O3)

  • Worsens respiratory conditions like asthma, emphysema, broncities, COPD

    • limits overall lung function

      • irritates muscles or respiratory tract causing constriction of airways & shortness of breath

      • irritates eyes

    • Sources: photochemical breakdown of Nitrogen Dioxide (car exhaust, coal & Natural Gas combustion)

  • ONLY HARMFUL IN TROPOSPHERE (beneficial in stratosphere)

Topic 8.15 (Pathogens & Infectious Diseases)

Pathogens & Vectors

  • Pathogen

    • A living organism (virus, bacteria, fungus, protist, worm) that causes an infectious disease

      • Infectious diseases are not transmissible (heart disease, asthma, cancer, diabetes)

      • Pathogens adapt and evolve to take advantage of humans as host for their reporduction and spread (Covid-19 is a SARS-associated coronavirus that evolved to become especially effective at surviving and reproducing in humans)

  • Vectors

    • A living organism (rat, mosquito) that carry and transmit infectious pathogens to other organisms

      • Climate change is shifting equatorial climate zones north and south away from the equator; this brings warmer temperatures to subtropical and temperate regions

      • Warmer temperatures allow pathogens and their vectors (mosquitos) to spread north & south to parts ot the world previously too cold

        • Many pathogenic bacteria and viruses survive and replicate better in warmer weather

Infectious Disease & Development

  • Less developed, poorer countries typically have higher rates of infectious disease

    • Less sanitary waste disposal; pathogens can reproduce in open waste areas where children may play or animals may scavenge & pass to humans

    • Less access to healthcare facilities and antibiotic medication to treat infectious diseases caused by bacteria & other pathogens

    • Lack of treatment/filtration for drinking water & sewage treatment exposes people to bacterial and viral pathogens in water, often from human waste

    • Tropical climates *& more open-air living can expose people to vectors like mosquitoes; less money fro vector eradication (spraying mosquito breeidng grounds)

Plague

  • Bacterial (pathogen) infection transmitted by fleas (vector) that attach to mice & rats (vectors as well)

    • Transmitted by fleat bite, rodent contact or contaminated human fluids

    • AKA “bubonic” or “black” plague; modern antiobiotics are highly effective against it, but some isolated instances still occur

Tuberculosis (TB)

  • Bacterial (pathogen) infection that targets the lungs

    • Transmitted by breathing bacteria from body fluids (respiratory droplets) of an infected person, which can linger in air for hours

    • Causes night sweats, fever, coughing blood; treatable in developed nations with access to powerful antibiotics

    • Leading cause of deaht by disease in the developin world ~ 9 million cases per year & 2 million deaths (for comparison ~ 2.8 million global deaths from Covid-19)

Malaria

  • Parasitic protist (pathogen) infection caused by bite from infected mosquitoes (vector)

    • Most common in sub-Saharan Africa (& other tropical regions of Middle East, Asisa, South & Central America; recurring flu-like symptoms; kills mostly children under 5)

    • Can be combated with insecticide spraying that kills mosquitoes; US eradicated in 1951

West Nile

  • Virus (pathogen) infection caused by bite from infected mosquitoes (vector)

    • Birds are the main host, but the virus can be transmitted by mosquitoes that bite infected birds and then bite humans

    • Causes brain inflammation, which can be fatal

Zika Vius

  • Virus (pathogen) infection caused by bite from infected mosquitoes (vector) & sexual contact

    • Causes babies to be born with abnormally small heads and damaged brains; can be passed from mother to infant

    • No known treatment currently, so prevention is focused on eliminating mosquito populations

SARS (Severe Acute Respiratory Syndrome)

  • Coronavirus (pathogen) infection caused by respiratory droplets from infected person

    • Primarily transmitted by touching or inhaling fluids from an infected person

    • Causes a form of pneumonia

    • Initial outbreak was in Southeast Asia

    • SARS-CoV-2 is the virus that causes the disease COVID-19

MERS (Middle East Respiratory Syndrome)

  • Virus (pathogen) respiratory infection transmitted from animals to humans

    • Originated on Arabian peninsula

Cholera

  • Bacterial (pathogen) infection caused by drinking infected water

    • Vomiting, muscle cramps and diarrhea; can cause severe dehydration

    • Can be introduced by water contmainated with human feces or undercooked seafood

UNIT 9

Topic 9.5 (Global Climate Change)