APES unit 9

stratospheric ozone layer

is important to the evolution of life on Earth and the continued health and survival of life on Earth

Stratospheric ozone depletion

is caused by anthropogenic factors, such as chlorofluorocarbons (CFCs), and natural factors, such as the melting of ice crystals in the atmosphere at the beginning of the Antarctic spring

how does a decrease in stratospheric ozone affect UV radiation on Earth?

it increases the UV rays that reach the Earth's surface

health impacts of UV radiation

can lead to skin cancer and cataracts (eye damage) in humans

Chlorofluorocarbons (CFCs)

A family of organic compounds whose properties make them ideal for use in refrigeration, air-conditioning, and aerosols

cause ozone depletion

How do CFCs and HCFCs destroy ozone?

chlorine atoms contained in the compounds are highly reactive

they interact with Ozone (O3) by stripping off one Oxygen molecule, leaving behind O2.

How can ozone depletion be mitigated (reduced)?

by replacing ozone-depleting chemicals with substitutes that do not deplete the ozone layer such as Hydrofluorocarbons (HCFs)

Even though HCFs do not deplete the ozone-layer, they are still an environmental concern because they

have a high Global Warming Potential and are thousands of times more powerful as a greenhouse gas than carbon dioxide

the principal greenhouse gases

carbon dioxide methane water vapor nitrous oxide chlorofluorocarbons

water vapor as a greenhouse gas

it doesn't contribute significantly to global climate change because it has a short residence time in the atmosphere (weighs more than gas)

global warming potential of carbon dioxide

GWP of 1

is used as a reference point for the comparison of different greenhouse gases and their impacts on global climate change

which greenhouse gas has the highest GWP (global warming potential)?

chlorofluorocarbons (CFCs) are over 10,000x as strong as CO2

how does the greenhouse effect contribute to life on Earth?

the greenhouse effect results in the surface temperature necessary for life on Earth to exist but trapping in heat which would otherwise escape in the absence of the sun

global warming potential of Methane

25 times that of Carbon Dioxide

Impacts of global climate change

rising sea levels, melting ice sheets, increased ocean temperatures and acidity, spreading of disease from the tropics toward the poles, melting permafrost, increased atmospheric temperatures

ice cores

Carbon Dioxide data and ice cores

positive impacts of changing sea levels on marine ecosystems

newly created habitats on now-flooded continental shelves

negative impacts of changing sea levels on marine ecosystems

deeper communities that may no longer be in the photic zone of seawater

impact of climate change on atmospheric circulation

can change circulation patterns, as temperature changes may impact Hadley cells and the jet stream

why are ocean currents important?

they are considered the ocean conveyor belt and carry heat throughout the world

changing currents can have a big impact on global climate, especially in costal regions

how can climate change affect soil?

changing temperatures and amount of rainfall can impact soil's viability and potentially increase erosion

what regions on Earth experience the most impact from climate change?

Earth's polar regions are showing faster response times to global climate change

why are polar regions more susceptible to climate change?

ice and snow in these regions reflect the most energy back out to space, leading to a positive feedback loop

what happens to the Earth as ice and snow melt? (the positive feedback loop)

less solar energy is radiated back into space and instead is absorbed by the Earth's surface. this in turn causes more warming of the polar regions

global climate change response time in the Arctic is due to

positive feedback loops involving melting sea ice and thawing tundra, and subsequent release of greenhouse gases like methane

albedo effect

the ability of a surface to reflect away solar radiation

measured from 0 to 1 with 0 being a pitch black surface (0% reflected) and 1 being a completely white surface (100% reflected)

one consequence of the loss of ice and snow in polar regions is

the effect on species that depend on the ice for habitat and food

ocean warming is caused by

the increase in greenhouse gases in the atmosphere

what are some examples of ways ocean warming can affect marine species?

loss of habitat, and metabolic and reproductive changes

may displace some species and cause them to migrate in new patterns

coral bleaching

caused by increased ocean temperatures

causes algae within corals to die and the corals bleach white

some corals recover and some die

ocean acidification

the decrease in pH of the oceans, primarily due to increased carbon dioxide concentrations in the atmosphere

ocean acidification chemical process

CO2 + H2O -> (H+) + (HCO3-)

Water and carbon dioxide combine to form carbonic acid (H2CO3), a weak acid that breaks (or "dissociates") into hydrogen ions (H+) and bicarbonate ions (HCO3-).

as more carbon dioxide is released into the atmosphere, the oceans...

absorb a large part of that carbon dioxide and become more acidic

the pH scale

scale with values from 0 to 14, used to measure the concentration of H+ ions in a solution

a pH of less than 7 is acidic, a pH of 7 is neutral, and a pH of greater than 7 is basic

Anthropogenic

derived from human activities

anthropogenic activities that contribute to ocean acidification are those that...

lead to increased carbon dioxide concentrations in the atmosphere: burning of fossil fuels, vehicle emissions, and deforestation

how does ocean acidification damage coral?

acidification makes it difficult for them to form shells, due to the loss of calcium carbonate

invasive species

species that can live and sometimes thrive, outside of their normal habitat

they can sometimes be beneficial but they are considered invasive when they threaten native species

are invasive species often generalists or specialists?

generalists

they thrive in a variety of habitats and can survive off a variety of foods

are invasive species generally r-selected or K-selected species?

r-selected

they reproduce frequently and produce a large amount of offspring when they do reproduce

therefore they may outcompete native species for resources

How can invasive species be controlled?

Mechanically (physically removing), Chemically (pesticides), Biologically (introducing natural predator), and Ecologically (manipulating environmental factors).

Examples of invasive species

kudzu vine, purple loosestrife, African honeybee "killer bee", water hyacinth, fire ant, zebra mussel, gypsy moth, Asian Long Horned Beetle, brown tree snake

factors that can lead to a species becoming threatened with extinction

being extensively hunted, having a limited diet, being outcompeted by invasive species, having specific and limited habitat requirements

which species are less likely to face the danger of extinction?

species that are able to adapt to changes in their environment (resilient) or that are able to move to a new environment

selective pressures

any factors that change the behaviors and fitness of organisms within an environment

how can competition among species lead to endangerment or extinction?

species in a given ecosystem compete for resources like territory, food, mates and habitat

what are some strategies to protect animal populations?

criminalizing poaching, protecting animal habitats, and legislation

HIPPCO

Habitat destruction, Invasive (nonnative) species

Population growth (too many people consuming too many resources)

Pollution

Climate change

and Overexploitation

describes the main factors leading to a decrease in biodiversity

habitat fragmentation

occurs when large habitats are broken into smaller, isolated areas

causes of habitat fragmentation

include the construction of roads and pipelines, clearing for agriculture or development, and logging

ways global climate change can cause habitat loss

changes in temperature, precipitation, and sea level rise

species domestication

some organisms have been somewhat or completely domesticated and are now managed for economic returns, such as honeybee colonies and domestic livestock

negative impacts of species domestication

can reduce the biodiversity of that species

what are some ways humans can mitigate the impact of loss of biodiversity?

creating protected areas, use of habitat corridors, promoting sustainable land use practices and restoring lost habitat

habitat corridors

protected strips of land that allow the migration of organisms from one wilderness area to another

habitat restoration

process of bringing a damaged habitat back to a healthy condition