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APS 325: Life in Extremes > Lecture 12: Arctic Ecosystem > Flashcards

Lecture 12: Arctic Ecosystem Flashcards

1
Q

arctic general characteristics

A
  • coldest biome above 66 N
  • youngest biome
  • slight overlap w boreal forest
  • 20-25% earth surface
  • variable ecosystems (top to bottom)
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2
Q

arctic characteristics: plants

A
  • 1700 spp. of plant
  • 400 spp of flowering plant
  • huge diversity of mosses and lichens
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3
Q

challenges for plants in arctic:

A
  • low temps and substantial variation (- to 20DC at bottom)
  • low soil fertility
  • drought conditions “polar deserts” (real and frost drought)
  • short and late growing seasons (as u move further north, grow season gets shorter)
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4
Q

benefits to arctic life

A
  • snow insulation (protection from winter cold)

- 24 hour daylight in summer (midnight sun)

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5
Q

are there seasons in the arctic??

A

yes, summer snow w some greens

winter = majority = snow

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6
Q

amount of ice covergae in arctic is important for

A

earths albedo

- increasing temps = less snow, less light reflected, more hitting earth, increased temps for earth

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7
Q

key adaptions for organisms in the arctic

A

few “unique” adaptions

- many based on avoidance rather then trus adaptions

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8
Q

adaptions specifically to plants: low stature and dense growth forms

A
  • traps air and insulates the plant
  • leaves at 90DC to sun can be 15 DC warmer
  • protection from wind/ice blast
  • covered by snow in the winter
  • e.g. Silene acaulis
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9
Q

Arctic plant adaptions for growth:

A 
• Low / dense growth forms
• Rapid response to spring
• Physiological activity at low
temperatures
• Freeze tolerance
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10
Q

adaptions specifically to plants: prostrate plants

A

also known as amt-forming plants

- especially in high arctic

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11
Q

adaptions specifically to plants: prostate plants & low stature and dense growth forms + organic matter

A

maintains organic matter better

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12
Q

adaptions specifically to plants: dwarfism

A

Salix polaris is a willow tree but v close and low to floor

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13
Q

low growth habitats also found in other biomes =

A

polar and desert (Arizona)

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14
Q

start of growing period in arctic =

A

spring, have to act fast at the beginning

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15
Q

low dense growth form examples

A
  • prostrate plants

- low stature and dense growth forms

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16
Q

plants response to spring:

A

rapid bud burst soon after or even during snow melt o maximise growing season
- issue: false signal?

17
Q

adaptions specifically to plants: maintain physiological activity at low temperatures

A
  • plants are adapted to photosynthesise at low temperature
  • allows growth in early spring
  • max growth even in a cool summer
18
Q

maintaining physiological activity examples

A

lichens (rlly good example)

  • lichen abundance and diversity INCREASES at higher latitudes (in contrast to vascular plants)
  • can photosynthesise at -5 DC
19
Q

adaptions specifically to plants: low nutrient availability means that tissue production is

A

tissue production is costly

  • mainly long lived perennial plants
  • reabsorb nutrients from dying leaves and root (litter produced = poor in nutrients)
  • slow growing
  • low nutrient conc in leaves
  • lots of investment in roots
20
Q

adaptions specifically to plants: lots of investment in roots

A
  • root:shoot biomass ratio is on average 6:1
  • not deep, just lots of shallow roots
  • roots live longer than leaves
  • BECAUSE of low nutrient availability
21
Q

LOW nutrients availability: N fixing legumes, parasitic plants, insectivorous plants

A

common to gain nutrients

22
Q

arctic plants and stress avoidance

A

LOW nutirents = LOW stress tolerance

  • N deficiency inhibits the protein synthesis necessary to recover from photochemical damage
  • bryophyte = top section is non-photosynthetic just a sunscreen to protect bottom
23
Q

arctic plants and solar tracking

A

common

  • arctic poppy
  • at 83 DC north
24
Q

arctic plants and desiccation resistance

A
  • despite snow, summer precipitation is low
  • ADAPTIONS:
  • – cushion, prostate & dwarf growth helps reduce water loss
  • slow growth demands less water
  • leaf adaptations (similar to that in deserts) i.e. rolled leaves
25
Q

climate change and carbon balance: ice loss

A
  • loss of ice, effects albedo, earth warming, poles continuing to warm
  • nearly 350km lost in 97-2014
26
Q

warming in arctic compared to rest of earth

A

a lot faster

- polar amplification

27
Q

arctic warming: boundary between Tree Line and Tundra is moving

A

North (forest is moving north)

28
Q

threats from global change on plants:

A

arctic plants live at the limits of plant life

  • adapted to cold
  • adaptions become less relevant
  • arctic plant communities sensitive to change
29
Q

arctic adaptations threatened by global warming :

A
  • adapted to short and cool growing seasons

- adapted to low nutrient availability

30
Q

arctic adaptations threatened by global warming: artificial winter /summer warming at low and high arctic

A
  • winter warming low arctic increases biomass

- summer warming high arctic increases biomass

31
Q

warmer winters = colder plants??

A
  • warm winters = less snow = less insulation

- Warm winters = more rain = more ice forms

32
Q

season length effects on flowers

A
  • warming = longer growth
  • season = better for pollinators?
  • differential effects on pollinators and on flowering plants
  • pollinators and plants relationship mismatch, relationsjip declining
33
Q

carbon balance calculation

A

Gross primary production (GPP) - Ecosystem respiration (ER) = Net Ecosystem Exchange (NEE)
- GPP - ER = NEE

34
Q

eddy covariance towers =

A

sensors CO2 change on large scale

35
Q

carbon balance calculation: arctic and arctic borders research =

A

swap from sink to source
=e.g. border Black spruce forest on permafrost
2002 – present (boreal forest)
-eddy covariance measured change in CO2 is, around 2006 became source instead of sink

36
Q

plants adaptions to the arctic ___ their sensitivity to global change

A

enhance

APS 325: Life in Extremes (15 decks)

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