C7 Human Dependence + Impact on Ecosystems

Question 1

ecosystem services

Answer 1

benefits supplied to humans by ecosystems, whether they be natural or man-made

Question 2

ecosystem services
- what?
- categories (4) and examples

Answer 2

benefits supplied to humans by ecosystems, whether they be natural or man-made
- Provisioning: products/resources obtained (wood, metals, wool, medicinal products)
- Regulating: benefits supplied by ecosystem regulation (pollination, erosion/flood control, climate regulation)
- Cultural services: non-material benefits (bushwalking, boating, religious activities, enjoyment)
- SUPPORTING SERVICES: overarching, necessary for entire ecosystem function (nutrient cycles, water cycle, Phs)

Question 3

Explain the problem with ecosystem services in today’s society.

Answer 3

• there is a clash between short term individual benefits, and long term ecosystem/societal benefits due to: undervaluing of ecosystem services, overvaluing of material products
• there is rapid, unsustainable human growth due to an increasing pop size and a larger per person consumption rate
• a lack of awareness leads to: decrease in biodiversity, alteration of ecosystems
• often human-caused disruptions are hard to reverse

Question 4

renewable vs non-renewable resources

Answer 4

RENEWABLE
- naturally replenish over time and can keep up with the rate of human consumption
- wood, wind, solar energy, water

NON-RENEWABLE
- do not renew themselves rapidly enough to keep up with the rate of human consumption
- coal, oil, gas, nuclear energy

Question 5

ecological footprint

Answer 5

• is a measure of the total ecological area that is required to sustain a person/population
• how much productive land/water something requires in order to produce all the resources it consumes, and absorb all the waste it generates
• measured in GHA (global hectares)

Question 6

biocapacity

Answer 6

• the capacity of an ecosystem to regenerate everything we use/demand from that area
• a measure of how much an area can sustainably provide to society
• 6 demand categories: cropland, fishing grounds, carbon, grazing land, forest products, built-up land (cities)

Question 7

ecological deficit/reserve

Answer 7

deficit/reserve are the difference between biocapacity and ecological footprint. (take one away from the other)

DEFICIT
- a regions ecological footprint is higher than its biocapacity
- the region is using more than is sustainably available to them

RESERVE
- a regions biocapacity is higher than its ecological footprint
- the region is using less than what is sustainably available to them

Question 8

State the factors affecting the ecological footprint.

Answer 8

• resource intensity in production of goods/services (how much is needed to produce something)
• consumption of goods/services per person
• population size

Question 9

Describe the relationship between a region’s GDP and ecological footprint.

Answer 9

• countries with higher GDP have larger ecological footprint per person
• they can afford more, and therefore consume more per person (buy more food/goods, live in larger houses, use more energy, use more water)

Question 10

pollution vs contamination

Answer 10

POLLUTION
- always human caused
- a substance introduced into an environment causes harm

CONTAMINATION
- not always human caused
- there are higher lvls of a substance than usual
- doesn’t have to cause harm

• there can be contamination w/o pollution, but for pollution to occur, contamination has also occurred.

Question 11

pollution
- sources (2)
- forms (5)
- impacts (3)

Answer 11

SOURCES
- human (deliberate or accidental)
- natural (volcanic ash, faeces)

FORMS
- organic (e.g. animal waste)
- inorganic (e.g heavy metals)

• organisms (invasive)
• nutrients (e.g. fertiliser)
• energy (light, heat, sound)

IMPACTS
- death to organisms
- decreased health (humans, organisms, ecosystems)
- reduced quality: soil, air, water

Question 12

categories of pollutants (3)

Answer 12

POINT VS NON-POINT
- Point: one single location that pollution is coming from, easier to identify and control (e.g. pipe)
- Non-point: multiple, dispersed source of pollution, harder to identify and manage (e.g. city air pollution)

PRIMARY VS SECONDARY
- Primary: active/harmful on emission (plastic, CO2, fertilisers)
- Secondary: not necessarily harmful on emission, must react to cause harm (formation of acid rain and photochemical smog)

PERSISTENT VS DEGRADABLE
- Persistent: cannot be decomposed, leads to build-up of pollutant, is passed along food chains, majorly affects high trophic lvls (heavy metals, DDT)
- Degradable: can be decomposed by enzymes or bacteria, does not lead to build up/passed along food chains (modern pesticides, bioplastics)

Question 13

eutrophication
- what?
- describe process

Answer 13

when water becomes enriched with nutrients due to runoff of artificial fertilisers used in farming (nitrates/phosphates)

PROCESS/CAUSES
- excess nutrients causes algal blooms
- algae block out the sunlight for plants underneath: without Phs, they die
- death of plants + the algae creates thick layer of dead biomass on bottom of waterway
- biomass must be decomposed by large amounts of bacteria, which through CR, use up all the dissolved O2 in the water
- without access to plants or oxygen,

Question 14

bioaccumulation vs biomagnification

Answer 14

BIOACCUMULATION
- the buildup of persistent chemicals within an organism, due to ingestion/absorption of a toxin
- most affects organisms with a longer lifespan, which have a longer time to accumulate the toxin (higher trophic lvls)
- poisoning occurs once toxin lvl gets too high

BIOMAGNIFICATION
- the buildup of persistent chemicals within a food chain, leading to higher concentrations within higher trophic lvls

Most affects high trophic levels:
- as the organism size increases, it must eat larger quantities of food to survive (due to trophic energy loss)
- leads to magnification of the pollutant due to a higher pollutant conc
- tuna, swordfish, shark etc

Question 15

State the abiotic factors that the impact of pollution can be measured through.

Answer 15

• pH
• nitrates/ammonia
• dissolved O2
• conductivity (ability to pass electric currents could indicate heavy metals)
• turbidity (how clear)
• faecal coliform tests (bacteria from animal guts)

Question 16

Describe how dissolved O2/BOD can be used to measure the impact of pollution.

Answer 16

• gets into water via: diffusion from atmosphere, movement of water, Phs by autotrophs
• it is often reduced in the presence of pollutants due to many decomposing bacteria (eutrophication)

Can be measured indirectly through BOD
- biochemical oxygen demand
- the amount of O2 consumed by bacteria + other organisms when breaking down organic matter
- when pollution occurs, more bacteria are required to break down the dead matter, increasing respiration, increasing the demand for O2

INCREASE IN POLLUTANTS = INCREASE IN BOD = DECREASE IN DISSOLVED O2

Question 17

Describe how biotic factors can be used to measure the impact of pollution.

Answer 17

INDICATOR SPECIES/BIOTIC INDEX
- species that are very sensitive to environmental conditions
- absence/presence/abundance of these will suggest the level of an ecosystem’s health
- the absence of several indicators of similar tolerance lvls may equal pollution

Question 18

wild harvest fishing

Answer 18

• global production of fish/seafood has quadrupled in the last 50 years in order to feed the growing population
• wild harvest is fish that are taken from the sea (pots, nets, trawling, dredging, traps, longline)

Question 19

WILD HARVEST FISHING
- describe the impacts of overfishing on aquatic ecosystems.

Answer 19

• when fish are being caught faster than the population can naturally replenish itself: too many adult fish are being caught to repopulate
• this significantly depletes populations = extinction (most threatens sharks/rays)
• population growth will continue to increase the amount of fish caught
• without change, overfishing will destroy ecosystems, biodiversity and ocean health beyond repair

Question 20

WILD HARVEST FISHING
- describe the impacts of habitat destruction on aquatic ecosystems.

Answer 20

Many methods of fishing destroy habitat.

DREDGING
- metal scoop to harvest clams etc is dragged along the sea floor
- churns up sediment
crushes coral/habitat
- digs up burrowing animals
- decreases water quality

SEAFLOOR TRAWLING
- nets pulled across to collect bottom-dwelling fish
- destroys coral/oysters/sponges (habitat)
- destroys filter feeders (vital for preventing eutroph by eating nutrients)
- depletes benthic fish pop.s (vital for nutrient cycles)

BLAST FISHING
- dynamite thrown into water, causes fish to float to surface for easy capture
- massively destroying species/habitat

Question 21

WILD HARVEST FISHING
- describe the impacts of derelict fishing gear on aquatic ecosystems.

Answer 21

Ghost fishing gear = gear that has been lost/abandones in the ocean

PLASTIC
- majority of ropes/nets are made of plastic
- lasts for centuries
- releases microplastics, eaten by organisms (cause internal harm + release chemicals)

ENTANGLEMENT
- captures targeted species: fishers have to compete with lost gear (e.g. pots/nets)
- captures non-targeted species (bycatch)
- injures organisms, or prevents from moving or coming up for air

CORAL REEF DESTRUCTION
- broken corals from ghost gear makes them vulnerable to disease
- nets block out light, preventing Phs

Question 22

WILD HARVEST FISHING
- describe the impacts of bycatch on aquatic ecosystems.

Answer 22

• are non-targeted species
• cannot always be released back, or may be injured
• removes species from sea that are vital to biodiversity/ecosystem
• has negative flow-on effects due to relationships between species

LONGLINE FISHING
- birds attracted to bait
- turtles get bait lodged in mouth and drown
- mammals become trapped in line

TRAWLING
- collects unwanted animals in nets

Question 23

Describe some solutions to combat the issues with wild fishing.

Answer 23

• better hooks/lines that target species and reduce bycatch
• ‘pingers’ on ships deter marine animals from the area
• bycatch reduction devices on pots
• different methods of collection (e.g. individual oyster harvesting instead of dredging)
• possibly aquaculture (fish farms)

Question 24

Describe the pros and cons of aquaculture (fish farms).

Answer 24

PROS
- large fish yield: feeds a growing population
- theoretical decrease in wild fishing: allowing pop.s to replenish
- recycles waste from fishmeal/livestock to feed fish

CONS
- mainly, large carnivorous fish are being farmed: means more fish must be caught in wild harvest to feed fish in farms
- habitat destruction: to make room for farms
- escape of non-native species: cross-breeding with local fish causes genetic modification, brings pathogens into ecosystems
- waste produced: uneaten fish food and faeces causes eutroph + smothers seafloor, hormones/chemicals used on fish cause bioaccumulation + bacteria resistance, pathogens/parasites are released from overstocking pens

Question 25

industrial vs sustainable farming

Answer 25

INDUSTRIAL FARMING - goal is to produce as much food as possible - use of: large scale machinery, fertilisers, pesticides - beneficial to farmers + consumers (low cost due to high yield) - ensures world food security with a steady supply of food SUSTAINABLE FARMING - goal is to protects enviro and human health - considers: soil health, animal welfare, conservation, energy efficiency, pest management, water usage - uses more money, time and space (habitat destruction) - however overall farm sustainability will likely increase farmer's profits

Question 26

IMPACTS OF AGRICULTURE: **nutrient cycles** - describe

Answer 26

- N, P, + others often limit growth in ecosystems - when harvesting crops, nutrients are taken out of the soil - adding fertilisers adds N/P back to soil - if enters water bodies: eutroph occurs

Question 27

IMPACTS OF AGRICULTURE: **chemical use** - pros - cons

Answer 27

PROS - for max land efficiency, chemicals are added - Pesticides: deal with fungi, insects, plants - Fertilisers: contain materials used for plant growth - result in a massive increase in production CONS - eutrophication - human health problems (eating produce, drinking contaminated water) - effects to beneficial non-targeted species (e.g. pollinators) - resistance may be developed against chemicals (making pest control more difficult)

Question 28

IMPACTS OF AGRICULTURE: **water use** - describe - environmental flows - virtual water

Answer 28

USE - watering crops (for human/livestock food) - cleaning of products/areas - drinking water for livestock - transport of produce - demand for water is increasing: growing pop, limited water on Earth ENVIRONMENTAL FLOW - water that is released from a dam to maintain river health (native species, water quality, reduce algae) VIRTUAL WATER - the 'hidden' water in goods/products/services used in the production of the product - the more steps in the production process, the more virtual water (e.g. meat vs plants)

Question 29

IMPACTS OF AGRICULTURE: **salinity** - describe - dryland salinity - wetland salinity - solutions (general, wetland specific)

Answer 29

- ancient salts in soil are brought to the surface via groundwater - causes: decrease in soil/water quality, native vegetation and crop death, reduction in biodiversity DRYLAND SALINITY - non-irrigated areas - removal of native trees reduces evapotranspiration - more precipitation goes into the soil than out - groundwater lvl rises, bringing salts to surface - shallow-rooted crops don't use enough water to counteract this - results in death of plants due to high salt conc WETLAND SALINITY - irrigated areas - land is irrigated, adding extra water, bringing up groundwater lvl - clearing of land also causes dryland salinity SOLUTIONS - leave vegetation as it is, no land clearing - replant native vegetation - reduce flow of water into groundwater (via interception) - pump out groundwater - change to more salt-tolerant crops will make land useful once more - plant multi-year, deeper rooted crops which will use more water Wetland - reduce water supply to crops (less excess) - improve irrigation techniques (reduce flood/boom irrigation released large water amounts, use drip line irrigation instead)

Question 30

Describe some solutions to combat the sustainability issues in agriculture.

Answer 30

CROP ROTATION - prevents monoculture, where soil is accustomed to a single crop - rotation naturally replenishes nutrients (esp legumes due to N fixing bacteria) - reduces pest/pathogen build-up WINDBREAKS - plants absorb less water, reducing water usage MULCHING - adds organic material back into the soil, replenishing nutrients RIPARIAN ZONES - forest either side of a river absorbs excess nutrients, preventing eutroph

Question 31

Outline the process of the **natural** greenhouse effect.

Answer 31

- incoming solar radiation (visible light, UV, infrared) from sun hits Earth's atmosphere - half of this is reflected/absorbed/scattered by atmosphere or clouds - remainder reaches Earth's surface: sea ice reflects some, heat (IR) is absorbed by land/sea - IR is reflected back off warm surfaces on Earth: is absorbed by GHGs in atmosphere layer (CO2, methane, H2O vapour), then reemitted back again to Earth's surface - GHG are essential: trapping of this heat keeps Earth inhabitable, w/o it, Earth would be far too cold

Question 32

Explain why GHGs are essential to life on Earth.

Answer 32

- the natural greenhouse effect - trapping of this heat keeps Earth inhabitable - w/o it, Earth would be far too cold to sustain life

Question 33

Outline the process of the **enhanced** greenhouse effect.

Answer 33

- reduction in carbon sinks (e.g. forests) and increase in carbon emissions (e.g. FF burning) - results in increased conc of GHG in atmosphere layer (CO2, methane, nitrous oxides, tropospheric O3) - atmosphere is a better insulator of heat: more IR absorbed + redirected back to Earth - denser layer prevents heat loss = warming of Earth temps

Question 34

weather vs climate

Answer 34

- weather: short term atmospheric changes - climate: average weather conditions over a long period of time

Question 35

PHOTOCHEMICAL SMOG - formed how? - type of pollutant - human sources - common time of year - impacts (human + enviro)

Answer 35

- nitrous oxides produced by internal combustion engines react with UV to form O3, combines with other pollutants + fog to form smog - secondary pollutant - Human sources: car exhaust, FF burning - Common time of yr: summer (hot sun) Impacts - Human: irritate eyes/throat, increase severity of resp. conditions, increase risk of resp. infections - Enviro: reduce Phs, reducing or stopping growth of plants + productivity

Question 36

INDUSTRIAL SMOG - formed how? - type of pollutant - human sources - common time of year - impacts (human + enviro)

Answer 36

- Formed from: sulfur dioxide + smoke particles - primary pollutant - Human sources: burning FFs - Common time of yr: winter (more FF burning for warmth) Impacts -Human: irritate eyes/throat, increase severity of resp. conditions, increase risk of resp. infections, KILL if bad enough - Enviro: reduce Phs, reducing or stopping growth of plants

Question 37

Outline some solutions to combat the formation of smog (both types).

Answer 37

* decrease use of FFs! * - limit transportation requiring petrol/diesel - limit excessive manufacturing - use renewable energy - use more energy efficient appliances/buildings

Question 38

Why does smog affect some cities and not others? (for each type)

Answer 38

- cities in basins/surrounded by mountains allows fog to settle - Industrial: high humidity traps sulfur dioxide + smoke, forming smog faster - Photochemical: increased sun exposure, dry, with calm winds, forms smog faster

Question 39

ACID RAIN - formed how? - Impacts (human, soil, forest, water)

Answer 39

- burning of FFs releases sulfur + nitrogen into the atmosphere - they react w water in the air, forming sulfuric acid + nitric acid, which falls as rain (or sometimes dry particles) Impacts - Human: breaks down limestone/marble, causes lung damage/resp problems - Soil: becomes acidic, decreases plant ability to uptake nutrients, harms nitrifying bacteria, increases solubility to toxic heavy metals - Forest: mass dying of plants, decreased productivity, increased vulnerability to enviro conditions - Water: death of sensitive species, decreased reproduction, leached heavy metals = poisoning, some water bodies too acidic to sustain life

Question 40

Describe how ozone is chemically formed.

Answer 40

- O3 is a gas formed naturally in the stratosphere - UV (sunlight) breaks apart O2 molecules - free O molecules then bond with O2 to create O3

Question 41

'good' ozone vs 'bad' ozone

Answer 41

Good ozone - located in: stratosphere (2nd layer) - forms the natural ozone layer - essential to life: absorbs majority of UV from sun, decreasing risks associated w sun damage (cancer/eye damage) Bad ozone - located in: troposphere (1st layer) - naturally low in quantity - burning of FF + sunlight + heat creates ground lvl O3 - common in larger cities/warmer weather/sunnier - secondary pollutant

Question 42

Describe how humans affect the formation of good AND bad ozone.

Answer 42

- burning FFs: contributes GHGs which react to cause ozone, creating tropospheric bad ozone - ODS (ozone depleting substances): destroy stratospheric good ozone, regulated by the Montreal Protocol

Question 43

Describe some of the impacts of bad (tropospheric) ozone on humans + enviro.

Answer 43

- Human: harmful when inhaled, causes smog, cardiovascular disease, worsens/causes resp. problems - Enviro: increases enhanced greenhouse effect, affects weather, decreases plant health (decreased: yield, lifespan, seedling growth, ecosystem function)

Question 44

Describe some other key effects of human induced climate change: 1. Sea level rise 2. Extreme weather events 3. Coastal erosion/flooding 4. Ice melt 5. Changing sea currents 6. Change of species distribution/behaviours 7. Decreased agricultural reliability

Answer 44

SEA LEVELS: - sea levels are rising and are predicted to continue to rise, this is due to: - as the oceans warm, the sea water expands taking up more space, causing water lvls to rise (thermal expansion) = ice/snow on the land (glaciers ) is melting, adding to the amount of water in the ocean EXTREME WEATHER EFFECTS - increased frequency and intensity of extreme weather - enhanced greenhouse effect results in higher global temperatures, increasing rates of evaporation and the air’s ability to hold moisture - this increases the frequency and intensity of: storms, precipitation, floods, droughts, wildfires, natural disasters (hurricanes, cyclones etc) - affects humans: resource supply (food/water/materials), safety and health, risk to housing and infrastructure, etc - affects enviro: species decline/extinction, habitat/resource destruction COASTAL EROSION/FLOODING - on and around coastline area experiences erosion and flooding more often - due to rising sea levels and increasing flooding/precipitation - damages ecosystems (habitats, soil health, organisms, resources) - damages human infrastructure, agriculture and aquaculture, etc ICE MELT - more ice caps/glaciers/sheets are melting worldwide - due to enhanced greenhouse effect increases global temperatures, causing more ice to melt - runs into rivers and streams, contributing to sea level rise - reduction in habitat for arctic/antarctic organisms CHANGING SEA CURRENTS - Earth’s major currents are driven by the sinking of dense salty, cold water - as sea temperatures warm, and ice sheets melt (adding fresh water back to the ocean), the density of the water is reduced, as it is warmer and less salty - this decreases its ability to sink and drive the global ocean currents, and slows/alters them CHANGE OF SPECIES DISTRIBUTION/BEHAVIOURS - the enhanced greenhouse effect due to burning of FFs causes changes in climate (warmer temperature in air/ocean, more frequent precipitation, different weather patterns, etc) - species distribution, behaviour, migration, and abundance are being affected, if they prefer/thrive in a specific environment - this further influences ecosystems (food webs) DECREASED AGRICULTURAL RELIABILITY - enhanced greenhouse effect results in more frequent, intense weather events (floods, storms, droughts, wildfires) - this damages agricultural land (decreased soil health, lack/excess of water, kills crops), livestock die - decreases global food security - decrease reliability on farming for economic gain

Question 45

Describe how human-induced climate change is causing **ocean acidification**.

Answer 45

- humans are increasing CO2 atmosphere levels, almost half of this is absorbed into the oceans - it reacts with water to form carbonic acid - this causes an increase in acidity (lower pH) due to a higher conc of H+ ions - H+ ions react with carbonate ions, decreasing the number of available carbonate ions - calcium carbonate is essential for marine organisms that need to build/maintain a shell or exoskeleton (crabs, coral, clams), therefore: = weaker shells/skeletons = dissolution of shells/skeletons

Question 46

Describe how human-induced climate change is causing **coral bleaching**.

Answer 46

- corals are comprised of a mutualistic relationship: coral animal, + symbiotic algae: which are the coral's food source and provide them their colour - increase in atmospheric CO2 has increased the greenhouse effect, causing Earth's ocean temp to rise - corals become stressed (heat), the algae produce harmful chemicals and the corals must expel it - corals lose their source of food - higher intensity and frequency of rising ocean temps leads to more frequent bleaching = less time for corals to recover, more corals die