unit 7 - sustainability and climate change Flashcards
(83 cards)
1
Q
what makes an ecosystem sustainable
A
if they can continue indefinitely
2
Q
resistance vs resilience
A
ability of ecosystem to be undisturbed despite change vs. ability of ecosystem to rebound from change
3
Q
what are the requirements for a stable ecosystem
A
- constant supply of energy
- nutrient cycling w/o leakages
- high genetic diversity
- tolerable climate variables
4
Q
why is a steady/constant supply of energy needed for a stable ecosystem
A
it maintains food chain by allowing energy to pass through
5
Q
why is nutrient cycling w/o leakages needed for a stable ecosystem
A
leakages lead to less nutrients over time in an ecosystem, nutrients get too low=ecosystem cannot continue
6
Q
why is high genetic diversity needed for a stable ecosystem
A
it handles change and is a way of resisting disease
7
Q
why is a tolerable climate needed for a stable ecosystem
A
- it’s what organisms are adapted to, big change = organisms cannot change as fast and will die
8
Q
what are some disruptions that can interfere with sustainability
A
- erosion -> washing away of soil = loss of nutrients
- harvesting and removing materials -> disrupts nutrient cycles
- eutrophication -> imbalance of nutrient enrichment
- epidemics + poaching -> possible food chain collapse
9
Q
tipping point meaning
A
occurs when enough disturbance has occurred to ecological balance, becoming near impossible to reverse
10
Q
positive feedback mechanisms meaning
A
situation that is being reinforced by the product of the situation
11
Q
what happens if the tipping point is reached
A
- there’s an abrupt change in ecosystem rather than gradual change
- often due to positive feedback mechanisms
12
Q
how does positive feedback mechanisms work in the amazon rainforest
A
- temps rise
- drought and wildfires increase in amazon
- more trees die/decompose/burn releasing CO2
- CO2 causes temps to rise further
13
Q
whats a mesocosm
A
a small ecological experiment in an open or closed ecosystem where conditions can be manipulated
14
Q
keystone species definition
A
species that has disproportionate effect on structure of an ecological community
15
Q
what happens when orchre sea stars (keystone species) are removed from an area
A
- barnacle species spread
- outcompeted by species of mollusk
- overcrowding
- loss of food and space leading to migration of species out of area
16
Q
requirements of a sustainable ecosystem
A
- nutrient availability (nutrient recycling must occur w/ no lack of chemical elements needed for life)
- detoxification of waste products (waste products of one species used a resource by another)
- constant energy availability (ex. sun)
17
Q
bioaccumulation vs. biomagnification
A
build up of toxins in tissue of organisms over time vs. increase in chemical concentration in individual organisms going up the food chain
18
Q
why are macroplastics (bottles, bags) dangerous to the oceans
A
- entanglement
- accidental ingestion
19
Q
why are microplastics (textiles, microbeads) dangerous to the oceans
A
- ingestion by filter feeders
- toxins can accumulate in bodies
20
Q
why are nanoplastics dangerous to the oceans
A
- bioaccumulate n organs/tissues of organisms
- full effects are not understood yet
21
Q
consequences of degradation of natural ecosystems
A
- loss of biodiversity
- increase in extinction
- loss of ecosystem services (ex. climate regulation, flood protection)
22
Q
what is rewilding, what is done during this process
A
practice of returning natural ecosystems to their original state
- stop human resource harvesting in area
- allow natural processes to restore habitat
- interventions may be taken to speed up restoration
23
Q
what are some possible rewilding interventions
A
- distribute seeds of missing plants
- reintroduce apex predators and keystone species
- connect ecosystems broken by fragmentation
- control invasive species
24
Q
hinewai reserve as successful example of rewilding
A
- 1250 hectors of farmland returned to natural forest
- alien mammals controlled w/ little interference by humans
- invasive species eliminated by better adapted native species
- however climate change and extreme weather are still threats
25
sustainable plant harvesting of brazil nuts
- grow in trees of amazon <- over harvesting will lead to no new young trees
- in order to be sustainable, some nuts are left behind in order to germinate and grow into new trees
26
sustainable fish harvesting of atlantic cod
- overfished in 1990s <- population almost went extinct
- fish are open access resource so conservation was limited
- in order to be sustainable now, fish must stay in range of max. sustainable yield (fishing must occur slower that rate of population growth)
27
what makes an agricultural practice unsustainable
an overuse of finite resources that cannot be sustained
28
tillage as an example of unsustainable agricultural practices
- the process of preparing soil for a crop
- soil becomes degraded and erodes quickly
29
nutrient depletion as an example of unsustainable agricultural practices
- when crops are removed, nutrients are depleted (desertification)
- when there are no nutrients, farmers use chemical fertilizers which leach into water sources and cause eutrophication
30
monocultures as an example of unsustainable agricultural practices
- same crop grown year after year in large areas
- increases pests, weeds and causes nutrient loss in soil
31
mechanical tillage as an example of unsustainable agricultural practices
use of diesel oil in tractors/heating greenhouses
- high carbon footprint
32
what is leaching
phosphates and nitrates in soil dissolved into waterways and into watershed
- caused by fertilizers, improperly stored manure
33
what is eutrophication
increase in nutrients in local waterways
34
what happens to a body of water when eutrophication occurs
1. nutrients go from land to water
2. aquatic plants grow rapidly
3. algae grows rapidly
4. algae bloom blocks sunlight from aquatic plants = water O2 levels fall
5. decomposition rate increases, aerobic respiration of decomposers reduce O2 further
6. death of organisms that requrie oxygen
35
crop rotation to make agriculture more sustainable
- varying crops harvest to harvest
- increases soil health and reduces pests
- ex. nitrogen fixing plants or companion planting
36
reducing/eliminating tillage to make agriculture more sustainable
- planting directly into undisturbed soil
- reduces erosion and improves soil health
37
planting cover crops to make agriculture more sustainable
- planting crops during off season
- prevents erosion, increases soil health, reduces pests, reduces fertilizer use
38
what are greenhouse gases
gases in atmosphere that retain heat
39
gases with largest warming effects on earth
carbon dioxide and water vapour
40
gases with less warming effects on earth
methane (more powerful but less abundant), nitrogen oxides
41
meaning of anthropogenic sources of climate change
gases released due to human activities
42
steps of the greenhouse effect
1. energy from sun reaches earth
2. some energy reflected into space, rest enters atmosphere
3. earth absorbs energy and emits heat
4. greenhouse gases absorb and re-emit heat energy (some into space, some back to earth)
5. heat effectively trapped and warms earth
43
evidence that CO2 levels correlate with average global temperatures
- cores of icebergs show annual layers which can be used to date air bubbles
- analysis of gas in bubbles show concentration of CO2 and the air temp at the time
44
positive feedback cycle of polar sea ice during global warming
- snow and ice reflect solar radiation <- has high albedo (reflects high proportion of light)
- as melting occurs, exposes more open water <- has low albedo (reflects low proportion of light)
- causes more heat to be absorbed by ocean = accelerated polar ice cap melting
45
positive feedback cycle of permafrost during global warming
permafrost = ground frozen all year
- melts due ot warming, exposing detritus (trash/debris)
- detritus decays and releases methane
- global heating accelerated, melting more permafrost
46
positive feedback cycle of solubility of CO2 during global warming
solubility of CO2 in water decrease as temp of water increases
- CO2 in atmosphere increases creates more warming
- ocean temps rise and CO2 becomes less soluble, releasing CO2 into atmosphere
47
positive feedback cycle of frozen hydrate methane cap during global warming
- stores of methane can have frozen cap so methane can't escape
- as ocean warms, cap may dissolve, releasing large amounts of methane which leads to more warming
48
positive feedback cycle of droughts and forest fires during global warming
- higher temps -> decreased humidity -> dry plants
- increases risk of forest fires which emit a lot of CO2 and kill trees
- reduced carbon capture in trees leads to more warming
49
why do boreal forests act as carbon sinks how may it shift to a carbon source
colder temps reduce cellular respiration and decay rate
- may shift into carbon source when tipping point is reached
- with increasing temps, forest fires increase <- after fires, boreal forests may be replace w more temperate forests with less trees
50
pack ice vs. landfast ice
ice that floats on surface of ocean and moves w wind and currents vs. ice attached to shore
51
how does a loss of ice affect emperor penguins
- breeds on landfast ice away from the shore (flatter, easier to move on)
- landfast ice becoming unpredictable-> breeding locations cannot be safetly found
- breeding too close to shore=more predation, breeding too far from shore = difficult to return to shore for feeding
52
how does a loss of ice affect walruses
- uses pack ice to rest b/w feeding and shelter from sea and predators
- sea ice of preferred for breeding becus of space and feeding range
- pack ice is melting = walruses now must travel further from land to feed/expend more energy keeping warm in cold waters
53
what does it mean that ocean is stratified
- made up of layers
- warmer less salty water floats on top of cooler saltier water
54
the mixing of ocean layers
- mixing occurs as heat seeps deeper
- greater the difference in density b/w layers, the slower the mixing
- mixing can create ocean currents (affects climate, winds, tides)
55
how does climate change affect ocean stratificaion
- warmer climate = surface of ocean warms and expands volume <- causes ice to melt adding freshwater and decreasing salinity
- creates larger diff in density=slower mixing = inhibits transport of heat, oxygen, CO2 throughout ocean
56
how is ocean stratification and climate change a positive feedback loop
- warm water on top cannot absorb as much CO2-> more CO2 in atmosphere->more warming
- warm water cant absorb as much O2 and it's harder to mix with deeper cooler layers
57
how does climate change affect the ocean biological zone
- deep water currents approach continental shelves and are forced upwards carrying nutrients (upwelling of nutrients) providing important nutrient cycling
- warming of ocean=more stratification=decreased currents=reduces upwelling-> disrupts ecosystems
58
how are upslope range shifts present in mountain ecosystems, what does this lead to
- species on mountain migrate upslope as climates lower warm up
- competitive exclusion occurs at high elevations and can drive species to seek marginal niches as new comp arrives
- leads to species extinction and threatened species at high elevations
59
how are poleward range shifts present in ecosystems, what does this lead to
- species have range with conditions they can tolerate
- at northern and southern edges of range, may be change in deaths/colonization which can shift species range
- with temps changing, in northern hemisphere, ranges of many species have shifted northward
60
equations of ocean acidification
CO2+H2O-->H2CO3 (carbonic acid)-->H+ + HCO3-(bicarbonate)
- hydrogen ions make ocean more acidic
61
what do sea creatures rely on carbonate for, what happens when there's not enough (ex. coral)
- to created calcium carbonate for shells and outer structures
- with less carbonate, calcium carbonate in coral skeletons dissolves
62
why are coral with calcium carbonate skeletons keystone species
other species rely upon them for food, shelter, and breeding
- loss of them can lead to total ecosystem collapse
63
how does climate change affect coral (and coral-zooxanthellae relationship)
1. loss of calcium carbonate for growth and strength due to ocean acidification
2. loss of mutualistic symbiosis with zooxanthellae (algae) due to temp increase<- water too warm = algae ejected from coral leading to coral bleaching and death
64
what is ecosystem diversity
the variety of ecosystems in a region, including the habitats, communities, and processes that support them
65
what is species diversity
variety of species in function and form
66
what is genetic diversity
variety in gene pool of each species
67
the last mass extinction was 66mya, what does this suggest?
that biodiversity is higher now than ever before
68
what are some causes of anthropogenic species extinction
- overharvesting
- invasive species
- pollution
- habitat destruction and fragmentation
- global climate change
69
what are the causes of ecosystem loss
- land use for agricultural expansion
- urbanization
- exploitation of natural resources
- mining and smelting
- dams and extraction of water for irrigation
- drainage/diversion of water
- leaching of fertilizers into river
- climate change
70
what is citizen science
a way scientists can get involved in collecting data regularly in area
71
what is the biodiversity crisis, evidence for this?
- unprecedented loss of ecosystems and species
- evidence: monitoring population size and range, diversity of species, area of ecosystem, # of threatened species, genetic diversity
72
what do high values of the simpson's diversity index mean
- used to quantify biodiversity of a habitat
- occur when equal #s of individuals in species are present and many species are present
- both eveness and richness are high
73
what is in situ conservation
protection/preservation of species in their natural habitat
73
sand dunes in pei, example of in situ conservation
- people go into sand dunes in order to remove invasive grasses
- preservation in normal environment
74
what is ex situ conservation
preservation of species outside its natural habitat
74
advantages of in situ conservation
- species lives in environments it's adapted to
- retains natural habitat and prevents loss of other endangered species
- costs are low if wildlife reserve in good state, limited human intervention
74
california condors as example of ex situ conservation
- in 1982 less than 22 left in wild
- because of captive breeding, now 210 in wild and 180 in captivity
75
advantages of ex situ conservation
- species may not be able to safely remain in natural habitats
- allows for control of conditions
- improve chances of successful breeding
- store living materials long term for future use
76
disadvantages of ex situ conservation
- doesn't prevent destruction of natural habitats
- species raised in captivity are less likely to be successfully reintroduced into environment
- increases inbreeding
77
what two criteria determine species most need of conservation
1. does the species have few or no close relatives?
2. is the species in danger of extinction because all remain populations are theatened?
78
what does EDGE stand for
evolutionarily distinct and globally endangered
79
what is biochemical oxygen demand
measure of how much oxygen is needed to break down organic matter in water
80
what is carbon sequestration
the storage of carbon dioxide from the atmosphere to slow down climate change
