Midterm 1

Question 1

Vegetation patterns exist in the tundra. Describe: Tussock tundra

Answer 1

Tussock tundra – special type of sedge meadow derived from dense clumps of the cottongrass Eriophorum vaginatum
• Comprise a large portion of carbon stocks

Question 2

There are 3 zones of the boreal forest, list them.

Answer 2

1. Closed boreal forest (southern)
2. Open boreal forest (northern)
3. Forest-tundra ecotone

Question 3

In terms of sea ice, define: Shore-fast ice.

Answer 3

coastal regions where ice grows out from and stays attached to the shore

Question 4

Describe this type of tundra tree: Krummholz

Answer 4

Krummholz – stunted wind-blown trees due continual exposure to fierce, freezing winds causes vegetation to become deformed

Question 5

Conifers dominate the taiga for many reasons, describe how being an accumulator species contributes.

Answer 5

Most conifers are accumulator species – hoard minerals
• accumulated nutrients aren’t recycled – don’t lose leaves
• fires are often needed to break down dead plant material

Question 6

Vegetation patterns exist in the tundra. Describe: Sedge meadows.

Answer 6

Sedge meadows: flat or rolling terrain dominated by a mat of grass-like sedge plants
• dense green swards or lawns in imperfectly drained lowlands, dominated by a variety of sedges (Carex sp) and cottongrasses (Eriophorum sp)
•Wettest after snowmelt – drier as summer goes on •Degrade with water pollution and grazing
• related to the open peatlands of the northern boreal forest

Question 7

What 4 things (basic) are needed for snow crystals to form?

Answer 7

Water Vapor + Ice Nuclei + Cloud Droplets + Temperature <4°C

Question 8

Define: Kettle hole.

Answer 8

A hollow created when buried blocks of glacier ice melt out.

Question 9

Conifers dominate the taiga for many reasons, describe how mutalism with mycorrhizae. contributes.

Answer 9

Most taiga plants have mycorrhizae – interweavings of fungal mycelium and root tissue.

Mycorrhizae are a mutualism between plants and fungi.
• the plant provides the fungus with carbohydrates
• the fungus helps the plant get nutrients from the soil, like nitrogen

Question 10

Describe the Pleistocene Epoch in terms of:

• How many glacial retreats/advances?
• How thick was the ice and how much land was covered?

Answer 10

A glacial period that had up to 20 glacial advances and retreats. There were massive ice sheets (3-4km thick) that covered 1/3 of earth’s land masses.

Question 11

List the 5 major ice ages that earth has experienced (in order).

Answer 11

1. Huronian.
2. Cryogenian.
3. Andean-Saharn.
4. Karoo.
5. Quatenary.

Question 12

• Reading by Dredge*
• What kind of ground was present in the natural environment of Northern Manitoba (pre-ice age). How was this ground formed?

Answer 12

Northern Manitoba (Canadian shield) is a mix of ancient remnants of the earth’s original crust and newer rocks. Old crust was folded through mountain building cycles, while newer crusts was created by volcanic activity (sediments). Most of Churchill’s topography developed in the Late Precambrian time. Limestone makes up much of the sedimentary rock, and is made up of silt or clay sediments and skeletons of calcareous marine organisms.

Question 13

What are ice wedges, and how does permafrost make them form?

Answer 13

Cold ground contracts in winter, cracks
• Cracks fill with water in spring
• Freezes and expanded by surrounding permafrost
• Forms ice wedges
• Repeat. Wedges grow over
time.

Question 14

Are bogs and muskeg’s low or high in nutrients? What is their environment like (temp and nutrients)?

Answer 14

• Low nutrients, but some plants are adapted to this and the chilly soils.

Question 15

Describe this principle force acting on sea ice:

• Ocean Currents

Answer 15

typically act in the opposite direction of the wind force
• act as a drag on the wind-driven sea ice motion
• important in longer-term ice motion (monthly to
yearly)

Question 16

Eastern and northern Manitoba’s Boreal Forest and peatlands are exceptionally rich in ___.

Answer 16

Eastern and northern Manitoba’s Boreal Forest and peatlands are exceptionally rich in carbon

Question 17

Define: Albedo.

What does this influence?

Answer 17

% solar energy reflected back into space (big influence on surface energy).

Question 18

How much of the world’s freshwater do cryospheres hold?

Answer 18

75%

Question 19

Describe ice nucleation active (INA) bacteria.

Answer 19

Presence on plant surfaces causes ice nucleation at temperatures 5-8° warmer than in the absence of the INA bacteria.

Question 20

• Reading by Dredge*

- Today, what is the climate of Churchill (basic)? Is it colder or warmer than previous times, and how can we know this?

Answer 20

• Marine subarctic climate. Most of northeast Manitoba has continuous permafrost (up to 80m thick in Churchill).
• There is evidence of tree migration when warm climates prevailed, and it is believed that trees were present 300km more north compared to now.

Question 21

Optimal function of enzymes is __-__ C.

Answer 21

Optimal function of enzymes is 37-40 C.

Question 22

Define: Tree line.

Answer 22

Treeline: northern boundary of the forest-tundra zone
• the zone where ‘forest with patches of tundra’ merges
into ‘tundra with patches of forest’
• the northern limit of the growth of trees that >5m high
• No distinct boundary - gradual change

Question 23

Has carbon energy pathway to benthic fauna changed over time? Explain this by answering the following question using the Atlantic walrus (a bioindicator).

These walruses are..
• Primarily benthivores
• Can consume 57kg of bivalves per day
• Central place foragers
• Haul-out in large aggregations

2) Is there latitudinal variation associated with different sea ice phenology?

(pretty much just yes or no)

Answer 23

Dependent on latitude and sea ice conditions • Jones Sound – no change, other areas had change.

Question 24

Boreal forest areas burning is highly episodic with high inter annual variability. Approximately 0.2 - 7.6 million ha are burnt a year. Is this increasing over time?

Answer 24

Yes, and will likely continue to increase with more climate change.
- There are more HUGE fires now compared to before (more area burnt), but smaller fires haven’t changed as much.

Question 25

First year ice vs multi year ice.

Answer 25

- First year ice forms in grades every year. | - Multi-year ice is a permanent ice zone, may contain younger ice and open water

Question 26

There are 3 types of fires, surface, crown, and ground fires. Describe surface fires in terms of what burns/where.

Answer 26

Surface fires: burn fuels at the ground surface • shrubs, grasses, fallen branches, litter

Question 27

How do invasive species post a threat to forests?

Answer 27

Invasive species can pose an even greater threat • no predators, diseases or other natural forces in Canada to control their population

Question 28

Define: Minerotrophic.

Answer 28

Fens are minerotrophic – water supply comes mainly from streams or springs.

Question 29

How are peatlands are growing points for permafrost throughout the taiga?

Answer 29

In summer, sphagnum dries out, insulates against incoming heat •Sphagnum soils are among the last to thaw in the boreal forest. In autumn, heavy rains and freeze-thaw cycles: sphagnum becomes water-saturated – conducts outgoing heat

Question 30

List 5 principle forces acting on sea ice.

Answer 30

1. Wind 2. Ocean Currents 3. Coriolis Force 4. Internal Ice Stress 5. Sea Surface Tilt

Question 31

CO2 levels are increasing by __% per year (anthropogenic cause).

Answer 31

1.5%

Question 32

How does permafrost freeze in winter (ie. from top or bottom?), and how does it thaw? What happens after it thaws?

Answer 32

* Active layer freezes in winter, thaws in summer (top-down) * After active layer thaws, the water can’t drain * Can have very wet and boggy ground in summer

Question 33

* practice exam question * T or F - Is the rate of ocean heat content now increasing faster?

Answer 33

True!

Question 34

How (and when) was Lake Agassiz formed?

Answer 34

- Ice sheets blocked meltwater from moving out into Hudson's bay, and formed a freshwater lake. - The lake covered most of the mid continent (including Manitoba) for ~5000 years. - Emptied 8000 years ago when the last ice sheet disintegrated, but left areas depressed by water and ice.

Question 35

One theory for the reason of more autochthonous lake input ("stuff" coming in from farther places) may be due to more run-off. Is there evidence for increased precipitation, and how would this cause the problem?

Answer 35

• Significant increases in total annual precipitation detected; Trend driven by summer rainfall. - Precipitation is increasing by +17-19 mm per decade.

Question 36

List the 3 layers of the nivean environment.

Answer 36

1. Subnivean 2. Intranivean 3. Supranivean

Question 37

What do climate change models predict in terms of insect outbreaks? What would be detrimental to insect outbreaks (ie. prevent them)?

Answer 37

* Increased temperature increases could increase the risk of future beetle outbreaks * esp. at high altitudes and latitudes where not as common currently • Extreme winter weather patterns (e.g., large temperature drops) are detrimental to beetle outbreaks

Question 38

Describe viruses in sea ice (part of food web).

Answer 38

- High ratio of viruses to bacterias, likely indicating high infection rates but limited information;.

Question 39

Describe this area within the boreal zone in terms of trees (basic): Forest-tundra ecotone.

Answer 39

transition between | taiga and tundra

Question 40

What kind of camera can be used to detect infrared (like an animal)?

Answer 40

- FLIR infrared camera.

Question 41

In terms of glaciers, what is plucking?

Answer 41

Glacier picks up rocks and sediment and deposits it elsewhere.

Question 42

What forms corn snow?

Answer 42

- meltwater or rain enters the snowpack | - Thawing and freezing cycle = increased vapor migration and freezing lead to large rounded grains

Question 43

Snow depth/ melt pond coverage largely control light availability in sea ice. How does attenuation doffer between snow and ice? What is attenuation?

Answer 43

- Snow – 15 m^-1 - Ice – 2m^-1 Attenuation is how easily light can penetrate something. Snow increases attenuation (less light scatter, less light for algal growth).

Question 44

* Reading by Dredge* | - Describe how Churchill evolved with its 3 major glaciations.

Answer 44

1st: The ice melting created a large lake/sea with clay deposits. Eventually land rose and water receded, leaving tundra-vegetation to cover the area. 2nd: Ice again formed and melted, leaving a sea and vegetation similar to what is seen today (tundra moss, shrub-sedge, birch communities) and animals like woolly mammoths, beavers, snails, and molluscs occupied the area. 3rd: This glaciation brought fossiliferous limestone debris and created the Glacial Lake Agassiz which covered most of the mid-continent.

Question 45

In terms of formation of snow pack, define: Constructive metamorphism (temperature gradient metamorphism).

Answer 45

New crystals are formed • Water vapor rises – moves from warmer area near ground • Water vapor crystalizes as it hits colder temperatures • With a greater temperature gradient, more vapor is transferred • More tightly packed near top • Bottom snow layers becomes loose, less dense, creating crystalline snow = depth hoar

Question 46

There are 3 types of fires, surface, crown, and ground fires. Describe ground fires in terms of what burns, and how they form.

Answer 46

Ground fires: burn subsurface organic fuels by smoldering combustion • often ignited by surface fires • found in deep peat deposits in a peat bog • burns most intensely & spreads fastest at the lowest levels • can move very fast • may smolder for days to months....then break out on the surface to be fanned by winds into full-scale crown fires

Question 47

Impacts of disturbances are influenced by spatial factors, temporal, and magnitude. Describe magnitude.

Answer 47

• Intensity - Physical force of the event

Question 48

Describe this type of tundra tree: Flagged trees

Answer 48

Flagged trees – branches grow on only one side, due to abrasion by wind and blowing ice crystals.

Question 49

*Reading by Pruitt* Describe this quality of snow cover that affects living organisms: Density. How does it affect animals (3)?

Answer 49

1. It expresses the water content of the snow cover, so dense snow will cause more spring run off. 2. Higher density can mean higher insulation for subnivian organisms. 3. The insulating properties of density makes the pukak layer warmer than the upper layers, allowing animal and bacterial activity to proceed (which increases carbon dioxide up to 5x more than outside).

Question 50

To stay alive in cold, life has a few options: Stay above 0C, or drop below 0C. In terms of staying above 0C, describe staying warm for *endotherms*.

Answer 50

- Adjust body temperature.

Question 51

What is the microbial loop in sea ice primary production? How important are bacteria?

Answer 51

- ≈50% of sea ice primary production is in the form of dissolved organic matter (DOM). - DOM is the main substrate for bacterial growth. - Microbial loop: Bacteria assimilate DOM into the biogenic particulate fraction that can be utilized by bacterivores, transferring carbon back into the classical food web. - Bacterial respiration has been estimated at 11% of primary production.

Question 52

# Define: Peat plateaus. Size?

Answer 52

Flat-topped areas of peat (smaller).

Question 53

What is a consequence of younger and thinner ice (old ice is melting)?

Answer 53

- more light transmitted through the ice = positive feedback loop of more warming

Question 54

The Anaktuvuk river fire was the largest fire on record for the tundra biome (2007), where the tundra ecosystem lost >2 kg C/m^2. What is the problem with so much carbon being released?

Answer 54

Overall, the fire released ~2.1 metric tons of C to the atmosphere • an amount similar to the annual net C sink for the entire Arctic tundra biome Carbon balance will subsequently be altered due to • reduced albedo (absorbs more energy) • removal of soil organic matter (less insulation) = Thaws permafrost

Question 55

What are pingos, and how does permafrost make them form? What are they similar to?

Answer 55

Subsurface water can freeze and force frozen ground upward (pressure) to form cone-shaped mounds with cores of ice. Similar to palsas, but are much bigger and they grow below the active layer (vs in the active layer).

Question 56

What is the main cause of ice ages (very brief)?

Answer 56

Changes in thermal energy.

Question 57

In ice as a biome, who are the algal primary producers and how much of the biomass are they? Does it change from first bloom to melt and late season?

Answer 57

- Pennate diatoms dominate bottom ice algal bloom biomass in the Arctic, can make up >90% biomass in the bottom ice algae community of landfast ice. - During melt, autotrophic flagellates tend to dominate. Sub-ice communities can also develop in late season (e.g., dominated by the chain-forming centric diatom Melosira arctica

Question 58

How do warmer summer temperatures affect fish who like cold water (trouts, walleye, Cisco)?

Answer 58

Species are using deeper, colder water in Ontario lake. Nearshore (littoral coupling) is lower with higher summer temperatures. Found in deeper waters when littoral zone warmer.

Question 59

Moose were found to *not* avoid roads/human activity. They did however, avoid deer. Why?

Answer 59

Brain worm – carried by deer in brain • Fatal in moose Larvae passed through blood into feces – then onto snails or slugs Causes sickness in white-tailed deer

Question 60

Sea ice is one of the largest biomes, and it's extent equals __-__% of the world’s ocean surface at any one point in time.

Answer 60

Sea ice extent equals 4-6% of the world’s ocean surface at any one point in time.

Question 61

List 2 ways/methods (general, not subcategories) boreal plants escape frost damage.

Answer 61

1. Extracellular (aka intercellular) freezing, which prevents intracellular freezing. 2. Supercooling.

Question 62

Describe this quality of snow cover that affects living organisms: Hardness. What influences it? Give an example of an animals it effects?

Answer 62

primarily influenced by wind and thaw; force required to collapse the api. Affects terrestrial mammals like caribou.

Question 63

* Reading by Warner * Canadian peatlands cover about __% of the land surface

Answer 63

Canadian peatlands cover about 13% of the land surface.

Question 64

* practice exam question * New data suggests that the ocean heat content is now rising much faster than before. By how much? (%).

Answer 64

50-75%

Question 65

Canada has the most surface water of any other country, what are these surface waters critically important to?

Answer 65

• All life and the maintenance of biodiversity on the landscape • A large range of ecosystem goods and services (e.g. drinking water, hydro power, agriculture, sanitation, commercial fisheries, recreation), big economic effect too

Question 66

List the 3 most abundant greenhouse gases, and how long each stays in the atmosphere.

Answer 66

1. Water vapour (9 days) 2. CO2 (up to 100 years) 3. Methane (12 years)

Question 67

Boreal areas can also be adapted to disturbance, what do larger scale disturbances create, and what animals can live here?

Answer 67

Larger disturbances, over time, create habitat for species that prefer large, uniform forests • marten, woodland caribou, & great grey owl

Question 68

Do bigger or smaller animals have a higher mass specific metabolism?

Answer 68

smaller animals.

Question 69

Why do conifers dominate the taiga? List their 6 main adaptions.

Answer 69

1. Short growing season. 2. Conical shape, dark colour. 3. Low surface area. 4. Tolerate nutrient poor soils. 5. Accumulator species. 6. Mutalism with mycorrhizae.

Question 70

Describe this principle force acting on sea ice: - Coriolis Force

Answer 70

causes objects to accelerate because of the rotation of the earth. • affect processes that occur at the global scale, such as ocean currents, winds, and ice motion • in the Northern Hemisphere, causes objects to deflect to the right • increases toward the poles – plays an important role in determining sea ice motion

Question 71

How are fens "fed"? Describe this. What "types" can they be?

Answer 71

Fens are minerotrophic – water supply comes mainly from streams or springs. Fens can be peatlands & mineral wetlands.

Question 72

Damage can be caused by _____ which feed & reproduce in the inner bark of trees; causes tree mortality. They essentially girdle the tree.

Answer 72

bark beetles (Scolytidae)

Question 73

Radiant energy from the sun warms the earth's atmosphere and surface (water and soil) and becomes heat energy. Describe this mechanism by which energy is transferred through the atmosphere: - Conduction

Answer 73

- Molecule to molecule (or solid to solid) exchange. - Depends on the temperature gradient, and rate of transfer varies by substance. - Air is a poor thermal conductor, while snow is a poor conductor.

Question 74

When did Canada develop peatlands? Do they span tot he high arctic?

Answer 74

Canada's extensive peatlands developed since the last glaciation < 10,000 years ago. Peatlands are rare in the High Arctic because climatic aridity and harsh growing conditions are not particularly conducive to peatland formation

Question 75

How does wind speed influence damage? Are damaged trees more susceptible to other problems?

Answer 75

Wind speed largely determines the extent of damage to trees • Larger trees are more susceptible to windthrow - lever • stands that have been recently burned Damage to tree stands increases the probability of pathogen outbreak and tree mortality

Question 76

Radiant energy from the sun warms the earth's atmosphere and surface (water and soil) and becomes heat energy. Describe this mechanism by which energy is transferred through the atmosphere: - Radiation

Answer 76

- Transfer of energy by electromagnetic waves (ie. sun in form of visible light). - Wavelength is related to vibration frequency: Long - infrared, short - ultraviolet.

Question 77

* Reading by Warwick * In terms of the ecological implications of changes in the arctic cryosphere, what effect does the warming arctic cryosphere have on: Permafrost. - Effect of more water, effect on vegetation and life once it dries up, contaminants.

Answer 77

- Erosion will release a lot of water that will ruin forests and turn them into fens, and can create many lakes and wetlands. - Southern invasive species. - Increased vegetation biomass with drier conditions can increase fires. - Thawing permafrost releases organic matter, gasses, inorganic solutes, and microbiota into the environment.

Question 78

What is the high arctic in terms of: - General area (relative to tundra) - Vegetation, ground, amount of snow - Winter thaw or no?

Answer 78

* northern tundra * vegetation is short * A lot of bare ground * less snow * No winter thaw

Question 79

How do amphipods combat freezing?

Answer 79

To combat freezing ice amphipods conform osmotically to their environment

Question 80

Animals in the arctic follow the SA/vol rule called the: __/__ power law

Answer 80

3⁄4 power law

Question 81

*Reading by Carlson + Windsor* - How long ago did the last ice age occur? - How does the melting of glaciers differ for glaciers on land (coastal vs inner) and on the ocean?

Answer 81

- 2.6 mya, ice sheets covered large portions of the northern hemisphere, which melted rapidly in the southernmost land margins, and retreated slower on land. Marine ice sheets had a delayed onset of retreat relative to temperature (retreat followed by rapid collapse).

Question 82

Define: Biome.

Answer 82

- A major geographical area characterized by a particular type of flora and fauna – primarily determined by CLIMATE. - A large-scale community of organisms shaped by common environmental conditions (climate and geology) • usually named after its predominant vegetation association • general and global, encompassing numerous smaller- scale ecosystems • e.g., Amazon Basin rainforest vs Congo Basin rainforest

Question 83

How long ago did this ice age occur? | - 1/5: Huronian

Answer 83

2.4 to 2.1 billion years ago.

Question 84

Describe this Milankovitch cycle explaining changes in insolation reaching earth: - Tilt. - How does it vary, and how long is the cycle?

Answer 84

- Axial obliquity: Ranges from degrees of 22.1 to 24.5 (currently 23.4 and decreasing). - 41k year cycle.

Question 85

Define: Supercooling.

Answer 85

lowering the temperature of a liquid or a gas below its potential freezing point, without it becoming a solid = Ice crystals cannot form at 0°C

Question 86

What is subsea permafrost, and how did it form?

Answer 86

Under the Arctic ocean, not in Southern hemisphere Formed >11,000 years ago, during the last ice age • Lower sea level • Exposed land froze When ice sheets melted, sea level rose & covered up areas of permafrost Today, some of seafloor still frozen up to 100m thick under seafloor

Question 87

Milankovitch cycles explain changes in insolation reaching earth. List the 3 different cycles/changes in orbit.

Answer 87

1. Eccentricity. 2. Tilt. 3. Precession.

Question 88

Where do peatlands occur and how much of this region do they cover globally?

Answer 88

Peatlands occur mainly in boreal regions, covering 25-30% of the boreal forest region globally

Question 89

How does the cryospheres influence the world?

Answer 89

Influences global energy balance and ecological functions of northern environments

Question 90

In terms of formation of snow pack, define: Destructive metamorphism (equi-temperature).

Answer 90

“destruction” of individual grains as snow settles (ie. by wind) • Decrease in volume • Increase in density (reduced space between crystals) • Occurs early in snow settling

Question 91

Define: Talik.

Answer 91

Soil or unfrozen ground, year-round, can be above, within or below permafrost

Question 92

___ can be a major fire season.

Answer 92

Spring.

Question 93

Boreal forest areas burning is highly episodic with high inter annual variability. Approximately how many million hectares are burnt a year (the range)?

Answer 93

0.2 - 7.6 million ha.

Question 94

Why do carbon concentrations in the atmosphere oscillate?

Answer 94

They go down a bit in summer due to increased plant photosynthesis.

Question 95

Main grazers of ice algae include heterotrophic protists (microfauna), metazoans that live within the sea ice (meiofauna), and under-ice metazoans. Describe the meiofauna of ice. What are the main ones, and how much algal life (and daily ice algae production) do they consume?

Answer 95

- Dominated by flatworms, crustaceans (including harpacticoid and cyclopoid copepods), nematodes, rotifers, and bentho- sympagic larvae - Consume about 1% of the ice algae standing stock and <6% of daily ice algae production

Question 96

What is the most widespread peatland in Canada? a. fen b. bog c. muskeg d. swamp e. tundra

Answer 96

B - bog

Question 97

Are we in a new epoch, and headed toward a "hothouse earth"?

Answer 97

- It is possible that we are driving the glacial-interglacial limit cycle toward a hotter state... - Even if the earth temperature stabilized, it's still hotter than at any time modern humans have existed.

Question 98

How long ago did this ice age occur? | - 2/5: Cryogenian

Answer 98

720 - 630 million years ago.

Question 99

Lightening fires are destructive in the boreal forest. They make up: –__% of total fires –represent __% of area burned

Answer 99

Lightening fires are destructive in the boreal forest. They make up: –35% of total fires –represent 85% of area burned

Question 100

Impacts of disturbances are influenced by spatial factors, temporal, and magnitude. Describe temporal factors (3).

Answer 100

* Frequency - number of events per unit of time * Duration * Time of year

Question 101

Describe how slopes can influence the amount of frozen ground present.

Answer 101

* slope facing towards sun get more sunlight (radiation) – facing south in northern regions * warmer ground = less likely to freeze (angles of insolation) * steep slopes do not get as much direct sunlight = relatively colder, also don’t hold as much snow

Question 102

Animals may experience severe range contractions and possible extinction due to environmental change... what 2 things can occur due to this? (Ie. genetically).

Answer 102

- Isolation. | - Genetic drift.

Question 103

In North America, what kind of forests would you find north?

Answer 103

Tundra.

Question 104

Describe this principle force acting on sea ice: - Wind What does it cause/how?

Answer 104

``` primary force responsible for ice motion • Short-term ice motion – days to weeks • causes the ice to drift – drag force • force depends on the speed of the wind and the characteristics of the sea ice surface • rough ice surface is affected more • Speed is predictable - sea ice that drifts freely moves at 2% of the wind speed ```

Question 105

Where would a jack pine be found (habitat)? Is it common in MB?

Answer 105

``` Jack pine (Pinus banksiana): continental, found on dry, sandy outwash plains and former dune areas – low nutrient, droughty substrates not tolerated by spruce and fir. • most common pine in Manitoba ```

Question 106

Do boreal ecosystems experience natural disturbances often? What are 4 major ones?

Answer 106

Boreal ecosystems are regularly subjected to large-scale natural disturbances - they're disturbance-based ecosystems: Major disturbances: 1) Fire 2) Insect infestations 3) Disease 4) Severe weather Boreal forest ecosystems are constantly changing Most boreal vegetation and wildlife species have adapted to, and depend on, disturbance.

Question 107

# Define: Discontinuous permafrost. How thick is it?

Answer 107

Discontinuous→ occurs under 50-90% of land in a defined area | • Up to 10 m thick

Question 108

What is the intermediate disturbance hypothesis?

Answer 108

- Highest diversity is often maintained at an intermediate level of disturbance. - Both frequency and scale of disturbance affect diversity

Question 109

How does dried peat have some uses for humans?

Answer 109

Dried peat is a traditional fuel in places where it is of high quality and easily accessible (e.g., Ireland). - Also in alchohol!

Question 110

Fire size in the boreal forest varies: • Most fires are small (___% are ___ ha these together represent 97% of area burned

Answer 110

Fire size in the boreal forest varies: • Most fires are small (70% are <5 ha) • only 3% of fires are >200 ha these together represent 97% of area burned

Question 111

__% of land (globally) has permafrost underneath. Over __% of Canada does.

Answer 111

24% of land (globally) has permafrost underneath. Over 50% of Canada does.

Question 112

Why is it colder at the poles of the earth (3 main reasons)?

Answer 112

- When sunlight hits the ground obliquely (at an angle), there's more surface area to cover and less absorption, so less amount of energy per unit area. - The sun's rays have to travel farther through the atmosphere at higher latitudes, resulting in less heat reaching the ground, less absorbed into the ground, and more reflected into the atmosphere. - Long nights in winter (months sometimes), more heat is lost to the atmosphere than gained at the surface.

Question 113

What 3 things can animals do if the environmental conditions change outside their tolerance?

Answer 113

1. Move (new location). 2. Adapt (adapt to new conditions in original habitat). 3. Go extinct.

Question 114

T or F: fires can cause a big decrease in forest soil depth.

Answer 114

True

Question 115

Why can’t trees grow in the far north?

Answer 115

The lack of summer warmth – not cold winters. • Photochemical reactions (photosynthesis) can only happen if plant tissues are warm enough • Results in low growth (leaves and roots are a necessity, wood/growth is a luxury).

Question 116

What is Clements' idea of a "superorganism"?

Answer 116

- Communities are "superorganisms") - Demonstrates that communities change over time in very discrete ways (like human development) ultimately resulting in a predictable endpoint

Question 117

Does any flora or fauna live on glaciers and ice sheets?

Answer 117

- Microbes can live on the ice surface or in solid ice. Microbe – any living organism that spends its life at a size too tiny to be seen with the naked eye. ‒ includes bacteria and archaebacteria, protists, some fungi and even some very tiny animals

Question 118

What’s the difference between a homeotherm and endotherm?

Answer 118

Homeotherm: animal that maintains an approximately constant body temperature. Endotherm: generates heat to maintain its body temperature. They rely primarily on their own energy reserves to produce heat in cold conditions.

Question 119

List a few things that can influence albedos.

Answer 119

Snow depth, age, vegetation, sunlight, cloud cover. Pollution (adds more cloud nuclei and changes reflection/absorption - thicker = more absorptive).

Question 120

Main grazers of ice algae include heterotrophic protists (microfauna), metazoans that live within the sea ice (meiofauna), and under-ice metazoans. Describe the under ice metazoans. What are the main ones, and how much algal life (and daily ice algae production) do they consume?

Answer 120

- Dominated by gammarid ice amphipods and planktonic calanoid copepods - Amphipod grazing rates estimated at 1-3% of ice algae - Calanoid copepods observed to graze on ice bottom, but no direct estimates to date - >65% sloughed ice algae floats or sinks slowly through the water column where it is primarily grazed by copepods - Gelatinous zooplankton are commonly observed feeding along the sub-ice environment - Arctic cod is a keystone species, providing a central link between grazers and higher trophic level fish, birds, and marine mammals

Question 121

What are 7 things that can influence the amount of frozen ground?

Answer 121

- Soil type - Lakes and rivers - Snow - Slopes - Wind direction - Plants - Peat

Question 122

How can plants accomplish extracellular freezing?

Answer 122

- “Antifreeze” accumulates inside cell walls (sap and other compounds) - Ice crystals form in between cells in intercellular spaces

Question 123

Is there a correlation between amount of peatland on a landscape and fire events? What else correlates to more fire events (relating to peatland)?

Answer 123

- Yes! | - Drought.

Question 124

* Reading by Warwick * In terms of the ecological implications of changes in the arctic cryosphere, what effect does the warming arctic cryosphere have on: Lake and river ice. - Increases in certain organisms, contaminants, invasive species.

Answer 124

- Less wind-induced mixing + more light for photosynthesis, will cause increases in zooplankton and contaminant transfer to high trophic levels. - Shifts habitat of cold adapted species. - Increases in mercury and other contaminants in fish. - Southern plants and fish can invade.

Question 125

How does the albedo in lake vs sea ice differ? What does this have to do with their type of growth?

Answer 125

- Albedo is much higher in sea ice due to the numerous impurities found in sea ice (lamellar growth) compared to lake ice (planar growth). - 99.9% of impurities are expelled from accreting lake ice - 10 to 40% impurities are trapped within sea ice

Question 126

What type of forest fires usually born most intensely and spread fastest?

Answer 126

Ground fires.

Question 127

List 5 things that cause the formation of layers in snow.

Answer 127

1. Wind→ increase wind, increase convection (primary driver) 2. Water Vapor→ vapor gradient between snow and air 3. Radiation→ Shortwave and longwave 4. Advected Heat (Rain) 5. Soil contact→ convection

Question 128

Define: Climate.

Answer 128

- Average state of Earth's surface conditions.

Question 129

In terms of sea ice, define: Pack ice.

Answer 129

almost constantly in motion, farther from shore, drifts in response to winds, currents, etc

Question 130

What is a problem with arctic warming in terms of light reflection (albedo)?

Answer 130

The Arctic is warming twice as fast as the rest of the planet • changing from a highly reflective surface to a very dark surface • Sunlight that would normally be reflected back into space (by sea ice, snow or glaciers) is instead being absorbed by dark surfaces (ocean, land & rock)

Question 131

What's the most recent glaciation in North America?

Answer 131

Wisconsinan glaciation.

Question 132

When Lake Agassiz was able to drain into Hudson's bay, and the depressions left filled with marine water, this became the ______ ______.

Answer 132

Tyrrell Sea.

Question 133

Fresh water is most dense at... a. 0C b. 2C c. 4C d. 6C e. 8C

Answer 133

c - 4 degrees.

Question 134

Describe how plants can influence the amount of frozen ground present.

Answer 134

• Keep soil cooler in summer – leaves can block sunlight from reaching the ground • especially evergreen trees • create bare ground at their base – loses heat easily • block sun in winter – more likely for frozen ground

Question 135

One way to reduce heat loss is to get bigger. Describe Bergmann's rule.

Answer 135

Animals of larger size are found in colder environments. Less SA/vol ratio, less heat loss.

Question 136

What happens to species that were around before the last glaciation?

Answer 136

Their range likely expanded and contracted over time.

Question 137

Low temperatures cause rigidity of membrane phospholipid bi- layers resulting in a loss of ion permeability. Production of ______ fatty acids (e.g., ___-__) play a particularly important role to avoid this increase in viscosity.

Answer 137

Low temperatures cause rigidity of membrane phospholipid bi- layers resulting in a loss of ion permeability. Production of polyunsaturated fatty acids (e.g., omega-3) play a particularly important role to avoid this increase in viscosity.

Question 138

What will happen to the tree line as the arctic warms?

Answer 138

* Trees move north * Temperature-induced drought * Animals will follow!

Question 139

How do insect outbreaks affect fire risk? | e.g. spruce budworm; Siberian silkworm

Answer 139

- Early summer drought *enhances* the insect population. - Forest structure (suitable host trees) *enhance* insect population further. - Insect population *reduces forest biomass* - Forest structure (ex. dead trees) and biomass *enhances* fire hazard. - Fire hazards *reduce* forest structure and biomass. - Climate *enhances* fire hazard - it's a cycle!

Question 140

__% of the land in the Northern Hemisphere freezes seasonally. • ~__ million square kilometers

Answer 140

58% of the land in the Northern Hemisphere freezes seasonally. • ~55 million square kilometers

Question 141

How can global warming change the carbon balance in the tundra?

Answer 141

Warming may change the carbon balance on the tundra – from a carbon sink to a carbon source - More carbon will be released due to decomposing microbes that release carbons, that won't be offset by increased plant growth.

Question 142

What is ecological succession?

Answer 142

* Communities change through time. | * Succession is the replacement of one community by another.

Question 143

Why are boreal forests so susceptible to large- scale insect disturbance? 2 main reasons.

Answer 143

1 Relatively lower species diversity = less predators | 2. Relatively lower productivity

Question 144

Describe Maritime snow in terms of: - General description - Snow depth - Layers of snow

Answer 144

Warm, wet, many melt features (ice etc..) - Snow depth: 75-500 cm - Layers of snow: >15

Question 145

What kind of tree is a tamarack, and where would it be found?

Answer 145

- Deciduous conifer that lives on thin, waterlogged substrate in level areas with permafrost. - Adapted to avoid water stress in spring.

Question 146

What 2 things determine snow crystal shapes?

Answer 146

1. Humidity | 2. Temperature

Question 147

There are 3 ways the sun's energy can be reflected and absorbed, list the 3 (and relative proportion of each).

Answer 147

1. Absorbed in the atmosphere (23%). 2. Absorbed at the surface (48%). 3. Reflected (29%).

Question 148

Boreal forests are exceptionally unstable in vegetation. What’s most important cause of disturbance in boreal ecosystems?

Answer 148

Fire.

Question 149

Define: Polynyas

Answer 149

* Persistent (and predictable) open water surrounded by ice * sustained by winds or ocean heat * often occur near coasts, fast ice, or ice shelves * One of the major lifelines to Arctic ecosystem structure and function

Question 150

How would an organism (ie. human) react to... - is below LCT - in TNZ - above UCZ

Answer 150

- is below LCT: shivering - in TNZ: changes in blood flow (dnm?) - above UCZ: sweat

Question 151

Are forests on the coasts more or less likely to burn? What other disturbances are also common here?

Answer 151

Forests on the coast are less likely to burn But other impacts: wind & coastal erosion resulting in death of conifers

Question 152

Are current CO2 concentrations very different from historic levels? Does it vary?

Answer 152

Over the past 20 million years, the Earth’s climate has oscillated between relatively warm and relatively cold conditions: •During interglacial periods, atmospheric CO2 concentrations were relatively high •during glacial periods, CO2 concentrations were relatively low. We are currently in an interglacial warm period

Question 153

To stay alive in cold, life has a few options: Stay above 0C, or drop below 0C. In terms of staying above 0C, describe staying warm for *ectotherms*. Many possible options revolving around a common theme!

Answer 153

Ectotherms don't produce their own heat, so must reduce heat loss (by habitat selection, move where it's warmer). - Can move underground. - Communal nesting/huddling. - Alternative life stage (in many inverts, overwinter in egg stage, ie. mosquitos). - Move into deeper water. - Move under snow (subnivian layer)

Question 154

Generally, Ectotherm = _____ e.g., most insects, fish, herps Endotherm = _____ e.g., most birds & mammals

Answer 154

Generally, Ectotherm = Poikilotherm e.g., most insects, fish, herps Endotherm = Homeotherm e.g., most birds & mammals

Question 155

What triggers insect population increases and associated widespread tree mortality? 2 reasons (causing 2 thing).

Answer 155

* sustained periods of abnormally warm weather * drought --> Both are correlated and create dry conditions. Multiple years of this can have a synergistic effect (much more damage than just 1 year).

Question 156

* practice exam question * New data suggests that the ocean heat content is now rising much faster than before. By how much? ``` A. 10% B. 50-75% C. 100% D. 150% E. No change. ```

Answer 156

B

Question 157

_____’s _____ forest is the largest remaining intact forest.

Answer 157

Canada’s boreal forest is the largest remaining intact forest.

Question 158

Describe Tundra snow in terms of: - General description - Snow depth - Layers of snow

Answer 158

Thin, windblown, no trees, few melt effects - Snow depth: 10-75 cm - Layers of snow: 1-6

Question 159

What was the largest fire on record for the tundra biome (2007)?

Answer 159

Anaktuvuk River fire in 2007 • burned > 1,000 km2 • largest fire on record for the tundra biome

Question 160

Describe how a pitcher plant in a sphagnum bog can still collect nutrients.

Answer 160

- Their red colour attracts flies and other meat-eating insects, they have hairs inside covered with a slippery gel. - The insects fall into the watery solution and are trapped and drown. - Plant secretes digestive enzymes into this warm, sun-heated solution; OR bacteria, microbes, and mosquito larva digest & the plant gets the waste products.

Question 161

What is the definition of Boreal Ecology (very brief)?

Answer 161

Ecology of the north.

Question 162

Describe this layer of a nivean environment, and give an example of an animal that may live here. - Intranivean

Answer 162

within the snow | • Area where some animals burrow, e.g. ruffed grouse

Question 163

T or F: Canada is home to the world's largest lakes and rivers.

Answer 163

True!

Question 164

Main grazers of ice algae include heterotrophic protists (microfauna), metazoans that live within the sea ice (meiofauna), and under-ice metazoans. Describe the microfauna of ice. What is the main one, and how much carbon is it consuming?

Answer 164

- Consume ≈1% of total particulate carbon during an ice algae bloom and do not seem to consume diatoms (Michel et al. 2002) - Mainly bacterivores

Question 165

Describe this quality of snow cover that affects living organisms: Density. What influences it?

Answer 165

primarily influenced by wind and thaw; measured as weight divided by volume • Expressed by water content

Question 166

Define: Tree line.

Answer 166

Treeline: northern boundary of the forest-tundra zone • the zone where ‘forest with patches of tundra’ merges into ‘tundra with patches of forest’ • the northern limit of the growth of trees that >5m high • No distinct boundary - gradual

Question 167

Describe Alpine snow in terms of: - General description - Snow depth - Layers of snow

Answer 167

Intermediate to deep, depth hoar & wind crusts, some melt features - Snow depth: 75-120 cm - Layers of snow: >15

Question 168

Boreal areas can also be adapted to disturbance, and smaller scale disturbances may create an "__" habitat. What is this, and what animals can live here?

Answer 168

Smaller-scale disturbances create ‘edge’ habitat • different forest types or landscape features come together • habitat for species such as moose, black bear and ruffed grouse

Question 169

What does the gyspy moth (invasive species/ alien) do? How were they introduced and why are they so detrimental?

Answer 169

* Defoliates a wide range of tree species, particularly hardwoods. * Concentrations are notable in urban areas such as Saskatoon and Winnipeg * introduced to North America in the late 1860s by a French naturalist attempting to cross the European gypsy moth with North American silkworms. His intent was to establish a silk industry on this continent. * overwinters in egg masses attached to the bark of trees; may contain 100 - 1,000 eggs

Question 170

What 3 major changes occur in the environment as a consequence of glaciation?

Answer 170

1. Change in climate patterns and zones (spatial and temporal). 2. Change in location and extent of suitable habitat (varies by species). 3. Routes of dispersal (Ice bridges vs water between land masses). - Overall, affects distribution of species.

Question 171

Define: Permafrost.

Answer 171

Frozen ground (@ or below 0°C) for > 2 yr.

Question 172

Define: The Suess effect in oceans.

Answer 172

- Oceans are carbon sinks. - Most of world's carbon is 12C, so environment is absorbing more of that isotope. - Changes in the ratio of atmospheric concentrations of the heavy and light isotopes of carbon are changing (due to increased CO2), there is less 13C and 14C now.

Question 173

____ is the bottom snow layer.

Answer 173

pukak

Question 174

How do algae counteract osmotic stress in ice?

Answer 174

To counteract the negative effects of osmotic stress on metabolism, ice algae accumulate organic osmolytes, also called “compatible solutes’’

Question 175

What is made when permafrost melts in the taiga?

Answer 175

drunken trees • trees displaced from their normal vertical alignment when permafrost melts - Can be sign of climate warming, up to 7-8% of trees in Alaska show signs of this now.

Question 176

There are 2 possible trajectories that earth can take... Describe: 1. The stable earth. 2. The hothouse earth.

Answer 176

1. Stable: High potential energy, little energy needed to move down hill. 2. Hothouse: Low potential energy, a lot of energy needed to move out of this state (harder to reverse).

Question 177

Define (basic) this quality of snow cover that affects living organisms: Duration.

Answer 177

Onset and disappearance of snow cover

Question 178

One theory for the reason of more autochthonous lake input ("stuff" coming in from farther places) may be due to more run-off. How much is precipitation increasing per decade?

Answer 178

Precipitation is increasing by +17-19 mm per decade.

Question 179

What is a glacier?

Answer 179

Ice capable of motion - expansion and contraction over time.

Question 180

How long ago did this ice age occur? | - 3/5: Andean-Saharn

Answer 180

460-430 million years ago.

Question 181

Which tree does the brown __tree name__ longhorn beetle threaten (invasive sp)? Their larva eat tree phloem.

Answer 181

Brown spruce longhorn beetle – threatens spruce forests under temporary periods of stress

Question 182

Describe this layer of a nivean environment, and give an example of an animal that may live here. - Supranivean

Answer 182

at or above the snow surface | • Area where some animals travel e.g., polar bear, Canadian lynx

Question 183

Many trees depend on recurring fires to reproduce. Describe this type of post-fire regeneration and list some plants/trees that use this method: - Serotinous or semiserotinous cones.

Answer 183

- Serotinous or semiserotinous cones (e.g. jack pine, black spruce) - Jack pine cones remain closed until the heat of a fire opens them to release the seeds inside (75% of cones) - Why would serotinous cones require heat of fire to open? It protects them from rain, frost, bacteria, fungus, most rodent teeth.

Question 184

What caused the formation of peatlands in Canada? What type of plants first grew?

Answer 184

Retreating glaciers left holes created by melting blocks of ice • Water could not drain into the underlying rock strata because of permafrost • The layer of cold water was colonized by sphagnum moss • Over time, develops a floating mat of vegetation • may support shrubs and small trees.

Question 185

Describe the formation of sea ice in terms of: | - What does formation begin with (___ crystals, where?)

Answer 185

Begins with frazil ice crystals (3-4mm in diameter) • At surface – begin accumulating and bonding with one another, chunks consolidate.

Question 186

* Reading by Warwick * In terms of the ecological implications of changes in the arctic cryosphere, what effect does the warming arctic cryosphere have on: Sea ice. - Animals (polar bears, walruses), water mixing + productivity, how it'll change human behaviour.

Answer 186

- Shift from birds and mammals to plankton and pelagic fish. - Decline in condition and reproductive success of polar bears. - More photosynthesis but less mixing means less nutrient distribution in deeper layers, limiting phytoplankton productivity. - Changes in food webs. - Increases in shipping, tourism, and oil/ gas/ mineral exploration that will further damage the habitats of animals.

Question 187

In terms of infrared radiation, describe good emitters/good absorbers, compared to a poor absorber..

Answer 187

- Good emitters are also good absorbers, and good absorbers reflect little energy (ie. dark pavement). - Poor absorbers reflect a lot of energy (ie. snow won't melt in sunshine).

Question 188

Impacts of disturbances are influenced by spatial factors, temporal, and magnitude. Describe spatial factors (4).

Answer 188

* Size * Shape * Connectivity * Proximity to unaffected areas

Question 189

In North America, what kind of forests would you find southwest?

Answer 189

Aspen parkland and prairie grasslands.

Question 190

Define: Acclimation.

Answer 190

Acclimation: • Non-heritable modification of characters • Caused by exposure to environment • Changes readily reversible

Question 191

There are 3 zones of the boreal forest, describe: - Forest-tundra ecotone in terms of: where it's found (global? Canada?)

Answer 191

* wide across much of northern Canada, but discontinuous patches across Alaska * especially wide in central Siberia– Russians often treat it as a separate biome, not a transition between 2 biomes

Question 192

Increased precipitation causes increased dissolved organic carbons in lakes, = increased thermal stratification and changes in transparency. How does this influence lakes?

Answer 192

- lead to shallower thermoclines and reductions of productive habitat in littoral zone ↳ less light can hit deeper spots. - Also less light which helps plant growth

Question 193

Ice melts when the temperature rises to 0°C – the melting point. Freezing is different – needs an ice catalyst (dust particle, impurity). At what temperature does *pure water* solidify at?

Answer 193

-40C at standard pressure.

Question 194

Landfast first-year sea ice has a surface ___ layer and bottom ____ ice layer.

Answer 194

Landfast first-year sea ice has a surface frazil layer and bottom columnar ice layer.

Question 195

Describe Ephemeral snow in terms of: - General description - Snow depth - Layers of snow

Answer 195

Thin, warm, wet, lots of melt - Snow depth: 0-50 - Layers of snow: 1-3

Question 196

What is happening with algae and their O2/CO2 use/release during these stages from winter to summer? 1. Pre bloom: 2. Increased sunlight, algal bloom: 3. Maximum sunlight, ice melting (=melt ponds):

Answer 196

1. Pre bloom (net heterotrophic): Using oxygen, making CO2. 2. Increased sunlight, algal bloom: Net O2 production, using CO2. 3. Maximum sunlight, ice melting (=melt ponds): Too much biomass, nutrients limited. Ice melt and too much light determine bloom end, the algae falls to the bottom and feeds other benthic organisms.

Question 197

Nutrients are largely a function of brine salinity in early spring. However, nutrient demand by blooming algae can rapidly surpass nutrients available in the sea ice. What 2 things can replenish nutrients?

Answer 197

Desalination and under-ice turbulence can replenish sea ice nutrients from the water column.

Question 198

What is refugia?

Answer 198

- Areas that provide suitable habitat for an isolated population of a once more widespread species; have not undergone ecological changes.

Question 199

Describe how lakes and rivers type can influence the amount of frozen ground present.

Answer 199

* sources of heat in colder areas * Water is warmer than the surrounding air, so keeps the ground beneath warmer in the winter * No frozen ground beneath

Question 200

What proportion of Ontario forest disturbances are caused by: 1. Blowdown and weather damage: 2. Harvesting: 3. Fire area:

Answer 200

1. Blowdown and weather damage: 44% 2. Harvesting: 30% 3. Fire area: 26% *know in general, not exact numbers

Question 201

Define: Mycorrhizae.

Answer 201

Most taiga plants have mycorrhizae – interweavings of fungal mycelium and root tissue. Mycorrhizae are a mutualism between plants and fungi. • the plant provides the fungus with carbohydrates • the fungus helps the plant get nutrients from the soil, like nitrogen

Question 202

What 4 ways can endotherms lose heat (modes of heat transfer), and to what is the heat transferred to?

Answer 202

1. Evaporation: Lose moisture. 2. Radiation (+ or -): Heat waves. 3. Condition (+ or -): To objects. 4. Convection (+ or -): To air

Question 203

The functioning of Boreal lakes is tightly linked to Boreal forest through terrestrial dissolved organic carbon (DOC). What are some sources for this DOC? How does this influence the lake?

Answer 203

* Decomposition of leaves and other plant material * Autochthonous and allocthonous input of energy (sediments or other things that came from other places) * Affects physical characteristics of the lake * Slightly “stain” the water clarity * Attenuates light * Affects thermal stratification

Question 204

# Define: Palsas. Size? | Grow in, below, or above the active layer?

Answer 204

Low frost heaves that contain permanently frozen ice lenses (larger, 1-3+ m). Palsas grow in the active layer.

Question 205

Define: Global carbon cycle (basic).

Answer 205

movement of carbon, in its many forms, between the atmosphere, oceans, biosphere, & geosphere

Question 206

What is CO2 fertilization?

Answer 206

The CO2 will fertilize the plants and increase food production (larger crops).

Question 207

What is secondary (ecological) succession?

Answer 207

Secondary succession takes place after an ecological disturbance

Question 208

The weight of ice sheets can cause the Earth's surface to sink. How does it rebound, and what is this called?

Answer 208

Isostatic Rebound. - When the ice sheets melt, the load on the crust and mantle is decreased. The mantle rebounds, and pushes up the earth's crust until it's back at equilibrium level.

Question 209

Define: Ombrotrophic.

Answer 209

Bogs are ombrotrophic ("cloud- fed") – receive all of their water and nutrients from precipitation.

Question 210

Describe this principle force acting on sea ice: - Sea Surface Tilt

Answer 210

differences in surface level • high and low regions caused by small differences in gravity

Question 211

Arctic Ocean net primary productivity has increased by __% since 1998.

Answer 211

Arctic Ocean net primary productivity has increased by 30% since 1998.

Question 212

Conifers dominate the taiga for many reasons, describe how tolerating nutrient poor soil contributes. How do they make it harder for other plants to grow?

Answer 212

- Live in immature soils that have little time to acquire organic material since the last glaciation (15k years ago). Fire disturbance every 1-2 centuries • Conifer needles are acidic. Acids drip from them during rain, slows decomposition, leach nutrients and minerals deeper into soil. • Shady year-round under closed-canopy – intercepts snow, which otherwise would form insulating cover on the ground. • permafrost develops more readily, further reducing the soil temperature. Soils under conifer stands are cold, with slow decomposition

Question 213

Define: Fire regime.

Answer 213

Fire regime: pattern, frequency & intensity of wildfires that prevail in an area.

Question 214

* Reading by Carlson + Windsor* | - What causes deglaciation?

Answer 214

Changes in earth’s orbit around the sun (increased energy) in addition to increased atmospheric carbon dioxide and other greenhouse gases.

Question 215

What kind of tree species would you find in the taiga (common names)?

Answer 215

- Spruces dominate. - Pines are very plentiful too. - Balsam fir, poplar, birch, tamarack.

Question 216

Jack pines have serotinous cones that require fire heat to open. Why is this beneficial?

Answer 216

It protects them from rain, frost, bacteria, fungus, most rodent teeth.

Question 217

What kind of disturbances are mouse reliant on?

Answer 217

Moose are a fire-dependent species • needs fire to create burnt-over habitat rich in deciduous browse, which will support these giant herbivores for a decade or two. Moose more likely in areas that had been burned or logged - They prefer disturbed areas! Mouse populations are declining in southeastern MB.

Question 218

Disturbance ecology shifts the focus from successional development of indefinite _____ communities to the dynamics of ecosystems (i.e. things keep changing).

Answer 218

Disturbance ecology shifts the focus from successional development of indefinite equilibrium communities to the dynamics of ecosystems (i.e. things keep changing).

Question 219

What is sphagnum? Is it common?

Answer 219

- Sphagnum – responsible for most of the organic buildup in the extensive peatlands of the north. - Sphagnum covers more of the world's land surface than any other single plant genus. - between 100 and 300 species of Sphagnum in the world (~50 sp in Canada)

Question 220

Define: Weather:

Answer 220

- Day to day state of the earth's surface conditions.

Question 221

What is basically occurring in an ice age?

Answer 221

A long term drop in global temperatures, causing an extension of continental ice sheets. They grow and decay regularly.

Question 222

Why might spring be a major fire season?

Answer 222

- Trees experience water stress in spring (lose moisture due to warm temperatures, gain little from frozen soil). - Usually low evapotranspiration because of short growing season, cool nights, frequent cloud cover, & sun’s low angle of incidence. - However, the fragile water balance can be disrupted in years with thick ice on lakes and a large high-pressure system lodged overhead •Under drought conditions, conifers are dry; lichen cattails, grasses & sedges are flammable • Fire season develops and large tracts of forest burn

Question 223

Define: Sporadic permafrost.

Answer 223

mostly in peatlands & under 10-50% of land in a defined area

Question 224

In boreal forests of Canada, insect-caused timber losses (tree death) may be up to 2 times greater than the mean annual losses due to fires. What 3 parts of trees may insects target?

Answer 224

* bark and wood-boring beetles - can recycle dying trees * defoliating insects (often Lepidoptera) * insects that attack roots and cones

Question 225

Has carbon energy pathway to benthic fauna changed over time? Explain this by answering the following question using the Atlantic walrus (a bioindicator). ``` These walruses are.. • Primarily benthivores • Can consume 57kg of bivalves per day • Central place foragers • Haul-out in large aggregations ``` 1) Has there been a change to phytoplankton-derived carbon to benthos?

Answer 225

- Lipid biomarkers used to calculate proportion of sea ice algal carbon relative to phytoplankton carbon in diet. - 15% decrease in sea ice concentration and 50% higher contribution of carbon from phytoplankton over time. - This caused 13C (carbon, not celsius) depleted compared to before when it was 13C enriched due to ice algae. - Increased contribution of phytoplanktonic carbon to benthos has dramatically increased over 34-years (and will amplify with continued climate change).

Question 226

Do bigger or smaller animals have a higher total metabolism?

Answer 226

larger animals.

Question 227

There are 3 types of fires, surface, crown, and ground fires. What are passive crown fires?

Answer 227

Passive crown fires: burn along ground, then spread onto each tree • the flame length (heat transfer) is enough to ignite individual tree crowns, but the canopy fuels and/or rate of spread are insufficient to maintain the fire both on the surface and in the crowns (active crown fire).

Question 228

How does low frequency disturbance affect biodiversity?

Answer 228

• short-lived species are outcompeted by long-lived species • Long-lived tend to dominate the community

Question 229

Define: Eskers.

Answer 229

Sedimentary material (gravel or sand) despoiled by streams flowing under or through glacial ice.

Question 230

Is fire disturbance important on the tundra? Are fires here common or rare, and will this change?

Answer 230

Historically, fires were rare on tundra • projected to increase with the warming climate, releasing more carbon, more chance of fires.

Question 231

___ caused timber loss may be 2x greater than the loss from fires.

Answer 231

insect

Question 232

The boreal forest has 3 zones based on tree cover, are they classified by specific species or something else?

Answer 232

Vegetation types are defined by community structure | • not specific species (which may be interchangeable)

Question 233

Do alpine tundras have permafrost? Do their soils drain?

Answer 233

Alpine tundra typically does not have permafrost | • soils are generally better drained than Arctic soils

Question 234

Is climate or weather more predictable? Is this changing in the arctic?

Answer 234

- Climate is more predictable, weather is not. | - Both are becoming more unpredictable in the Arctic.

Question 235

In terms of ice ages, what are "interglacial"?

Answer 235

Pulses of warm periods.

Question 236

Thermal gradient between body core & environment can range up to 100oC. As this gradient increases, the cost of maintaining constant internal conditions ____.

Answer 236

Thermal gradient between body core & environment can range up to 100oC. As this gradient increases, the cost of maintaining constant internal conditions increases.

Question 237

Give an example of something that can be an ice nuclei.

Answer 237

Many chemicals, contaminants, and impurities will act as ice nuclei • dust particles, bacteria

Question 238

What was the earth called during the cryogenian ice age, and what arose from this?

Answer 238

- "Snowball earth". | - A lot of phyla (the first ancestor) arose.

Question 239

Are forests with periodic surface fires less flammable? Why or why not?

Answer 239

Forest with periodic surface fires much less flammable than one where light fuels have accumulated for years * Root systems of shrubs and trees usually left alive * Within 3-4 years, few visible signs left of the fire

Question 240

Describe this type of lake: Deep oligotrophic.

Answer 240

``` 3. Deep oligotrophic lakes • Most common • Less nutrients • Rocky, sandy bottoms • Less algae • Oxygen is found at higher levels throughout water column – best water quality • Thermal stratification in the summer ```

Question 241

What are the implications of sea ice having a lammellar (spiky) bottom? *maybe not important

Answer 241

- Constitutionally supercooled layer, increases surface area for algal growth and traps brine throughout the ice.

Question 242

What is the issue with increased CO2 in the atmosphere?

Answer 242

CO2 increases the atmosphere’s ability to hold heat

Question 243

what 3 things must plants & animals deal with in cold boreal conditions? *not vital

Answer 243

* extended periods of cold • Dry and drought | * Low nutrients

Question 244

In North America, what kind of forests would you find southeast?

Answer 244

Deciduous hardwood forests.

Question 245

What TYPE of tree species would you find in the taiga (ie. conifers, deciduous, etc)?

Answer 245

Floristically poor, relatively few species but mostly conifers, some deciduous trees along water ways.

Question 246

Define: Adaption.

Answer 246

Adaptation: • Accumulation of genetic changes • Increases survival or reproduction in a particular environment • Not readily reversible

Question 247

Eutrophication in lakes can deplete oxygen at the bottom of lakes and thus kill some primary producers, how does this impact predators (they also lose visual acuity in murky waters)?

Answer 247

- Less primary consumers

Question 248

Describe how soil type can influence the amount of frozen ground present.

Answer 248

Soils freeze differently (i.e. light- colored soils freeze sooner and stay frozen longer than dark) • light colours reflect energy, dark absorbs • Pavement versus snow

Question 249

How do different isotopes of carbon alter the fractionation in kinetic and chemical reactions?

Answer 249

* Diffuses at a slower speed | * Harder to break chemical bonds

Question 250

Qualities of snow cover influenced primarily by ___ and the occurrence of ___ ___ or ___-____ cycles

Answer 250

Qualities of snow cover influenced primarily by wind and the occurrence of winter thaws or freeze-thaw cycles

Question 251

Describe why this hypothesis for extinctions may not be true: Introduced species - "overkill" by human hunters.

Answer 251

- People entered North America via the Bering land bridge. | - Problem: Very few humans to wipe out so many species.

Question 252

Defoliation can be caused by ______ which feed voraciously on new foliage & defoliate trees at high densities

Answer 252

jack pine budworm

Question 253

How does a glacier form? What is the firn limit?

Answer 253

- Begins with snow (called firn- granular snow that's not yet compressed) that's modified through geological processes. - Under the firn limit is ice, above it is snow. - Glacier size depends on the balance of accumulation vs ablation.

Question 254

Acclimation vs adaption

Answer 254

Acclimation: • Non-heritable modification of characters • Caused by exposure to environment • Changes readily reversible Adaptation: • Accumulation of genetic changes • Increases survival or reproduction in a particular environment • Not readily reversible

Question 255

What 2 things happen to plant tissues when water freezes?

Answer 255

* destroys living tissue due to the expansion of water inside the cell * sharp ice crystals can damage and kill cells

Question 256

How are bogs "fed"? Describe this. How common are they, and what "type" are they?

Answer 256

Bogs are ombrotrophic ("cloud- fed") – receive all of their water and nutrients from precipitation. - All bogs are peatlands and bogs are the most widespread peatlands in Canada (followed by fens).

Question 257

Radiant energy from the sun warms the earth's atmosphere and surface (water and soil) and becomes heat energy. Describe this mechanism by which energy is transferred through the atmosphere: - Convection

Answer 257

- Movement of a fluid (water or air). - Transfer of heat (current) from one place to another. - Radiator heats air, it becomes less dense and it rises.

Question 258

Is cryosphere (glaciers and ice) a biome?

Answer 258

* Typical geography and biology textbooks describe tundra as the coldest biome * Permanent ice as biome is a novel concept

Question 259

Boreal forests recover quite fast from fires (1-2 years in some cases), and fires can cause a habitat mosaic. What does this mean?

Answer 259

• More diverse habitats can elevate species diversity in an area.

Question 260

Phytoplankton blooms happen during and after sea ice breakup (after ice algae blooms). • How is a warming climate changing this phenology?

Answer 260

- Sea ice is breaking up earlier, causing earlier algal blooms and larger phytoplankton booms, followed by periods with no bloom (before ice returns). - There is increasing water thermal stratification due to climate change too.

Question 261

Is sea ice disappearing in a linear or non linear rate? What are the consequences of this?

Answer 261

- Ice minimum extent is decreasing at a non-linear rate - Ice melt contributing to freshening of surface water = greater stratification - more ocean is exposed every year = more light and increased atmosphere-ocean coupling.

Question 262

What do fire cycles determine? What's the time scale for average natural fire cycles, and does it differ in some areas?

Answer 262

Fire cycle – determines many of the plant dynamics • Natural fire cycle averages 50-200 years • Fire-prone areas (sandy ridges, rocky outcroppings) burn more frequently.

Question 263

Radiant energy from the sun warms the earth's atmosphere and surface (water and soil) and becomes _____ _____.

Answer 263

heat energy.

Question 264

Frozen water expands __% in volume.

Answer 264

Frozen water expands 9% in volume.

Question 265

There are 3 zones of the boreal forest, describe: - Open boreal forest (northern) in terms of: canopy (and result of that), another name, and why it may be given this name

Answer 265

* Trees grow far enough apart that a canopy never forms – sunlight & snow penetrate * Also called the lichen woodland: open woodland, with a sparse stand of conifers set in a ground layer dominated by lichens

Question 266

Many trees depend on recurring fires to reproduce. List 3 types of post fire reproduction.

Answer 266

1. Light, wind dispersed seeds. 2. Serotinous or semiserotinous cones. 3. Stump sprouting.

Question 267

Do jack pines encourage or prevent fires in the boreal forest? How?

Answer 267

Jack pine: self pruning and self-shedding reduce risk of crown fire * Sheds most of its dead branches and needles to reduce buildup of combustible fuels in the canopy * Self-pruning low on the trunk removes ladder branches (which can carry a surface fire up into the crown)

Question 268

Describe this area within the boreal zone in terms of trees (basic): Tundra.

Answer 268

land without trees

Question 269

Taiga & tundra are the primary terrestrial biomes in the North • Why not in the South?

Answer 269

There's much more land mass in the north, the south is mostly water.

Question 270

* If more carbon enters a pool than leaves it, that pool is considered a net ____ ____. * If more carbon leaves a pool than enters it, that pool is considered net ____ _____.

Answer 270

* If more carbon enters a pool than leaves it, that pool is considered a net carbon sink. * If more carbon leaves a pool than enters it, that pool is considered net carbon source.

Question 271

Why are black spruce's considered fuel ladders?

Answer 271

* Stand structure and tree architecture of black spruce are highly conducive to fast moving crown fires * Thick moss-covered forest floors readily transfer flames to the lower limbs and into the canopy

Question 272

Describe this Milankovitch cycle explaining changes in insolation reaching earth: - Eccentricity. - How does it vary, and how long is the cycle?

Answer 272

- Varies from circular to elliptical. | - 100k year cycle.

Question 273

Describe the formation of sea ice in terms of: | - What temperature does it form at?

Answer 273

Forms at ~ -1.8°C

Question 274

How can we know that temperature changes have occurred in northern Manitoba?

Answer 274

- Can identify shifts in northern boundaries of forests, due to pollen records of bogs, aspen, and spruce reflect tree line shifts over time (indicating cooling and warming periods).

Question 275

INA bacteria presence on plant surfaces causes ice nucleation at temperatures 5-8° warmer than in the absence of the INA bacteria. How have these bacteria been modified and why? What is it called?

Answer 275

Ice-minus bacteria: genetically modified mutant that doesn’t produce the ice-nucleating surface protein. •Prevents crop damage

Question 276

How do algae (which are mostly benthic adapted, like to stick to surfaces) get into sea ice? 2 main methods.

Answer 276

1. Scavenging: Picked up by fazil crystals (which form at depths), then get stuck to the ice once it forms. 2. Sieving: Turbulance or brine drainage causes the sticky algal cells (due to exopolymeric substances/EPS).

Question 277

What is primary (ecological) succession?

Answer 277

Primary succession | takes place on land where no organic soil exists – pioneer plants

Question 278

What’s the difference between a poikilotherm and ectotherm?

Answer 278

Poikilotherms: animals that have a variable body temperature over time. e.g., moths and butterflies Ectotherms: generally do not produce sufficient heat to maintain a constant body temperature. Rely primarily on external sources of heat. – However, may have constant temperature depending on behavior and environment.

Question 279

Rising global temperatures may increase the number of lightning strikes over the rest of the 21st century • __% increase for each degree Celsius

Answer 279

Rising global temperatures may increase the number of lightning strikes over the rest of the 21st century • 12% increase for each degree Celsius

Question 280

What does "stability" mean in the context of earth?

Answer 280

More likely to stay in the current state.

Question 281

Many trees depend on recurring fires to reproduce. Describe this type of post-fire regeneration and list some plants/trees that use this method: - Light, wind dispersed seeds.

Answer 281

- Light, wind-dispersed seeds (e.g. birches, poplars) | - Aspen catkins produce small fruit that split to release lots of tiny, cottony seeds that are dispersed by the wind

Question 282

Arctic temperatures are changing __ -__ times faster than in other areas.

Answer 282

3-4x

Question 283

How many terrestrial mammal species went extinct in the late Pleistocene?

Answer 283

- 35-40 large bodied mammals (mammoths, giant ground sloths, sober tooth cats, giant bisons).

Question 284

Which area of the boreal forest has the most fires: east, middle/central, or west?

Answer 284

Mostly in the middle, and they go quite far up north.

Question 285

T or F: Old arctic ice is disappearing.

Answer 285

True - Ice is becoming younger and thinner.

Question 286

List the 2 sources of changes in thermal energy that can cause ice ages.

Answer 286

1. Earth centre (inner core). | 2. Insolation (from the sun).

Question 287

Vegetation patterns exist in the tundra. Describe: Fell fields

Answer 287

Fell fields – stony tundra area where vegetation is thin and discontinuous – supplants heath tundra and tussock tundra in drier areas

Question 288

How often do ice ages happen?

Answer 288

They are cyclical, 44k - 110k years.

Question 289

does brain size correlate with trophic position?

Answer 289

yes

Question 290

In North America, what kind of forests would you find west?

Answer 290

- Montane and coniferous, and moist coniferous closer to the pacific coast.

Question 291

Rising global temperatures may increase the number of lightning strikes over the rest of the 21st century - if there's a 4C projected increase in temperature between 2014 and 2100, how many more lighting strikes will there be (%)?

Answer 291

48% more lightening strikes.

Question 292

What is the 1st and 2nd largest component of the climate system?

Answer 292

First is oceans, the second is cryosphere.

Question 293

Describe this type of lake: Eutrophic.

Answer 293

1) Eutrophic • Shallow and have murky water and mucky, soft bottoms. • Nutrients carried into lake from landscape • High levels of biological productivity • High biomass of algae, fish and other aquatic organisms • Fine balance – too much algal blooms and eutrophication (anoxic zones)

Question 294

Are there exceptions to Bergmann's rule? Why?

Answer 294

- Yes, animals tend to be smaller at higher latitudes. | - Likely attributed to primary productivity, if you're bigger, you need more energy.

Question 295

Define: Kame.

Answer 295

A hill or hummock composed of stratified sand and gravel laid down by glacial meltwater. - Accumulates in a depression on a retreating glacier, and is then deposited on the land surface with further melting.

Question 296

Describe how snow can influence the amount of frozen ground present.

Answer 296

A thick layer of snow acts like a thermal blanket – traps heat

Question 297

What 3 potentially problematic things can be released with thawing permafrost?

Answer 297

1/2. Releases CO2 and methane (microbial decomposition; speeds up climate warming). 3. Mercury (15 million gallons, 10x more than the amount of Hg emissions over the last 30 years).

Question 298

Conifers dominate the taiga for many reasons, describe how their low surface area contributes contributes.

Answer 298

* Needleleaf - narrowness reduces surface area through which water may be lost (transpired). * Needles also have thick waxy coatings - a waterproof cuticle * Stomata are sunken and protected from drying winds.

Question 299

What are isotopes of carbon? List the 3 main ones, and what makes them an isotope. Which ones are more common?

Answer 299

- 14C (radioactive), 13C and 12C (stable isotopes), - Forms of the same element that differ in the amount of neutrons in the nucleus. - Lighter ones are most common.

Question 300

List 4 qualities of snow cover that affect living organisms.

Answer 300

1. Duration. 2. Thickness. 3. Hardness. 4. Density.

Question 301

What 2 things cause seasons?

Answer 301

1. The tilt of earth on the N/S rotation axis. | 2. It's orbit around the sun.

Question 302

Why is sphagnum able to dominate?

Answer 302

Dominance of Sphagnum due to ability to absorb and retain water. • Absorbs 8 times its weight in water due to leaf anatomy • Closely packed sphagnum creates wick-like columns of moss, which lift water to the top of a sphagnum hummock (capillary action).

Question 303

Lake trouts prefer temperatures of <13C and high dissolved oxygen concentrations, meaning they have a much smaller possible habitat in summer. Have the thermal and dissolved oxygen barrier changed over time? I.e. have summer gotten longer and hotter?

Answer 303

Evidence of earlier ice melting, longer springs, and the cooling of lakes to <15°C occurring later in the fall... suggests that the summer period has shifted later into the year. Due to the later onset of fall, ice-on became delayed, and paired with earlier ice-offs, the winter ice-covered period became shorter over time.

Question 304

Conifers dominate the taiga for many reasons, describe how their conical shape and dark colour contributes.

Answer 304

* Conical shape – promotes shedding of snow & prevents loss of branches. * Dark color – helps the foliage absorb maximum heat from the sun and begin photosynthesis as early as possible * start of the growing season

Question 305

Describe how (domed) bogs are established, including the role of sphagnum (6 major steps).

Answer 305

Sphagnum can establish whenever precipitation > evaporation • Water fills depressions 1. Spreads mostly by spores (it’s a moss!) 2. Over many years grow into a large mass of floating moss • “floating blob” stage 3. Starts diverting water – blocks flow into and out of the site • Cuts off nutrients & minerals necessary for competitors • Accumulation seals off the mineral soil 4. Begins to produce acid, killing off plants that can’t tolerate it 5. High acid and low oxygen kills many decomposers – dead plant material starts to accumulate 6. Mounds of organic material begin to collect. Peat accumulates, bog takes on a raised (domed) profile

Question 306

What are some ways animals rely on snow and sea ice?

Answer 306

Protection from predation Thermoregulation | Nursing, birthing and resting

Question 307

How does arctic cod avoid freezing?

Answer 307

Arctic cod, use antifreeze glycoproteins to lower the freezing point of their tissues, blood and digestive fluids

Question 308

After sphagnum establishment – some species perform counter tactics. List 3 species that can do this, and how.

Answer 308

- Leatherleaf, Labrador tea, bog rosemary. Leathery, sturdy, evergreen leaves remain on plant for several years •less energy & nutrients needed to start growth in spring •many fine, hairlike structures on undersurface of leaves → to soak up more water •thick, waxy coat on upper surfaces – reduces water loss

Question 309

How is climate change influencing benthic organisms (especially macroalgae, is there more or less of it now)?

Answer 309

There's much more macroalgae cover.

Question 310

Define: Insolation.

Answer 310

Total amount of solar radiation energy received on a given surface area during a given time.

Question 311

Describe the Wisconsinan glaciation (most recent in North America) in terms of: - How long ago it was. - How much of land was covered in ice.

Answer 311

- 85,000 - 11,000 years ago. | - Covered 80% of North America.

Question 312

Describe the formation of sea ice in terms of: | - What does it become in calm waters vs windy waters?

Answer 312

* In calm waters – grease ice | * Windy waters - pancake ice

Question 313

* Reading by Dredge* | - How long ago did the last ice sheet disappear from Churchill, and what was the name of this ice sheet?

Answer 313

The Laurentide Ice Sheet disappeared from Churchill 8000 years ago.

Question 314

Vegetation patterns exist in the tundra. Describe: Wet tundra

Answer 314

Wet tundra: standing water remains over most of the summer • more widespread and less uniform than tussock tundra • develops in flat, marshy areas, usually with Cottongrass plus true sedges

Question 315

Many trees depend on recurring fires to reproduce. Describe this type of post-fire regeneration and list some plants/trees that use this method: - Stump sprouting.

Answer 315

- Stump sprouting (aspen, paper birch). | - Birch & aspen regenerate vegetatively by shoots and suckers arising along the long lateral roots.

Question 316

Does tree line advancement northward depend on temperature?

Answer 316

“Water availability rather than temperature appears to be an increasingly limiting factor for the northward progression of the treeline” Advancement will be patchy where there’s enough moisture

Question 317

How can wind cause forest disturbances? | How many hectares can be destroyed by this?

Answer 317

Severe weather events can cause small or large areas of forest to blowdown • can result in some or all trees within an area to break off (windsnap) or uproot (windthrow) Blowdown events usually range from 5 to 50 hectares in Ontario • up to 500,000 hectares

Question 318

Snow depth/ melt pond coverage largely control light availability in sea ice. How does albedo differ between snow and ice?

Answer 318

Albedo ̈ Snow – 0.8 ̈ Ice – 0.4

Question 319

What is the result of glacier abrasion, and how does it occur?

Answer 319

Smoothing of rocks as a result of ice flow.

Question 320

# Define: Peat. Where does peat form?

Answer 320

Peat: an accumulation of partially decayed vegetation • forms in wetlands or peatlands, variously called bogs, moors, muskegs, pocosins, mires, and peat swamp forests.

Question 321

What is a cryosphere?

Answer 321

Places were water is in solid form (not solely polar): - Frozen ground - Glaciers - Icebergs - Snow cover - Sea ice * Found every continent (even Africa, snow topped mountains)

Question 322

Pure water solidifies at -40C. What does water require to freeze at lower temperatures, and at what temp can it freeze at with these things?

Answer 322

Above -40°C, pure water needs a catalyst to transition to ice. • Ice crystals can act as catalysts. • the freezing point of water under equilibrium conditions (when an ice crystal is present) is 0°C.

Question 323

What are thermokarst lakes, and how does permafrost make them form?

Answer 323

• Irregular surfaces of marshy hollows and small hummocks • Caused when permafrost thaws and soil collapses

Question 324

* Reading by Warwick * In terms of the ecological implications of changes in the arctic cryosphere, what effect does the warming arctic cryosphere have on: Snow. - Animals, microbial life, plants.

Answer 324

- Increasing winter precipitation in the arctic. - Decreased snow cover duration (due to warmer air temperatures). - This together is causing winter rains and freezings that cover the surface of snow in ice, impeding animal foraging. - Organisms in snow (bacteria, fungi, snow algae) provide organic carbon and nutrients to the soil under snow during melts, and warmer temperatures can cause southern plant life to invade and outcompete the lichens and bryophytes present. - Without an insulating layer of snow, buds and shoots can be damaged and killed, reducing primary production. - Changes in growing season change the food resources available to arctic herbivores.

Question 325

Why are peatlands important? What is then a problem if peat is degrading due to climate change?

Answer 325

Peat is important because it stores organic carbon that otherwise could be released into the atmosphere as carbon dioxide or methane (carbon sink). If peat is disappearing, there will be more CO2 and methane in the environment.

Question 326

*Reading by Pruitt* What is pukak (in terms of snow), how is it made, and why is it important?

Answer 326

- Metamorphosed layer of large snow crystals, extending 10cm or more. - In the absence of wind, snow crystals settle undisturbed on other snow crystals, and are metamorphosed by heat and moisture rising from the earth below. - Important for subnivean mammals.

Question 327

Describe how wind direction can influence the amount of frozen ground present.

Answer 327

* If a slope faces into the wind, the ground will lose more heat through convection * Wind blows snow, making the ground even colder * Wind-blown slopes are more probable to have frozen ground.

Question 328

What is the low arctic in terms of: - General area (relative to tundra) - Vegetation, ground, amount of snow - Winter thaw or no?

Answer 328

* southern part of tundra * complete vegetation cover * patches of shrubs * lots of snow * Can have winter thaw

Question 329

Describe this type of lake: Mesotrophic.

Answer 329

2) mesotrophic • a medium amount of nutrients • usually clear water with submerged aquatic plants • These lakes stratify: colder bottom, warmer surface

Question 330

What are 4 big consequences of water eutrophication?

Answer 330

``` 1. Reduce water clarity • Affect acuity of visual predators 2. Harms water quality • Large algal blooms • Cyanobacteria – toxic 3. Raise water pH • Blind chemosensory predators 4. Hypoxic and Anoxic zones at bottom • Depleted or removed O2 at bottom due to microbial decomposition ```

Question 331

Describe why this hypothesis for extinctions may not be true: Glaciation-induced climate change.

Answer 331

- Problem: Extinction were very abrupt (for geological time). - Only seemed to affect large mammals or birds.

Question 332

# Define: Continuous permafrost. How thick is it?

Answer 332

Continuous→ occurs under all the land surface in a defined area, except beneath large water bodies • Often >100m thick

Question 333

T or F: It's warmer closer to ground surface than at snow surface

Answer 333

True

Question 334

in terms of this principle force acting on sea ice, the speed is predictable - sea ice that drifts freely moves at __% of the wind speed

Answer 334

2%

Question 335

``` Canada is home to: • __ of World’s lakes that are > 1km^2 • __ of 50 longest rivers across World • _00,000 km2 of surface water • Overall ~ __% of World’s wetlands ```

Answer 335

Home to: • Half of World’s lakes that are > 1km2 • 5 of 50 longest rivers across World • 800,000 km2 of surface water • Overall ~ 25% of World’s wetlands

Question 336

Fire size is a function of ____ and _____ (2 things that contribute to the size).

Answer 336

Fire size is a function of fire weather severity (e.g. dryness) and the connectivity of fuels (vegetation) on the landscape.

Question 337

Generally, Ectotherm = Poikilotherm and Endotherm = Homeotherm. But what about these 2 examples? * Several deep sea fish * Hibernating Mammals

Answer 337

* Several deep sea fish (homeothermic ectotherms) | * Hibernating Mammals (poikilothermic endotherms)

Question 338

Lake trouts prefer temperatures of <13C and high dissolved oxygen concentrations. Why might the summer season be problematic?

Answer 338

Temperatures close to the surface are hotter, and there's less oxygen at the bottom of the lake, meaning that it's preferred habitat is much smaller in the summer.

Question 339

Fire is the primary agent of change in the boreal forest. Describe 2 ways it can cause change.

Answer 339

1. releases nutrients • fires reduce plant litter (leaves, logs & conifer needles) on the forest floor and releases nutrients from these materials 2. allows more sunlight • Fires also open the canopy to sunlight which stimulates regeneration from seeds and roots (growth and reproduction).

Question 340

If peatlands are rich in carbon, what would happen in high temperatures and fires? Is a feedback loop established?

Answer 340

* Higher temperatures could increase the rate of decomposition, releasing carbon. * Increased fire frequency could release more carbon trapped in peat. Positive feedback between increasing temperatures and CO2 emissions • Exacerbates the problem

Question 341

There are 3 zones of the boreal forest, describe: - Closed boreal forest (southern) in terms of: density, canopy, soil, nutrients, permafrost.

Answer 341

* Dense forest, trees form a closed canopy | * Cold soils, low nutrients, permafrost

Question 342

How does high frequency disturbance affect biodiversity?

Answer 342

• no time for certain species to mature • community is dominated by species with a rapid growth rate, a short life span, and a strong ability to colonize disturbed areas (annuals)

Question 343

Define: Depth hoar.

Answer 343

* Depth hoar→ coarsest grains of snow usually found near the soil surface (sugar snow) * Grains are larger and poorly bonded to one another * Forms subnivean zone → Small animals can use this as shelter in winter * Destabilizes snow→ avalanches

Question 344

What are the relative % surface albedos of: - Fresh snow or ice - Soil - Water

Answer 344

- Fresh snow or ice: 60-90% - Soil: 5-30% - Water: 5-10%

Question 345

*Reading by Pruitt* What is api snow?

Answer 345

The snow on the ground (in the taiga).

Question 346

Vegetation patterns exist in the tundra. Describe: Polar desert

Answer 346

Polar desert – barren areas of bare rock, shattered bedrock, and sterile gravel. • An extreme form of fell field in the high Arctic • Lichens important – key for large herbivores

Question 347

What is the active layer in permafrost?

Answer 347

Above permafrost; seasonal thawing and freezing.

Question 348

How did moving ice change geology of the Canadian Shield?

Answer 348

- Glacier abrasion (due to ice flow) can smooth rocks. - Plucking (glacier picks up rocks and sediment and deposits it elsewhere). - Caused deposition of rich silt. - Some areas that previously had remnants of earth's original crust were overlaid by sedimentary rock (limestone).

Question 349

What are some natural causes of disturbances? There are 6, list 4.

Answer 349

``` Natural: • Floods • Glaciers • Fires • Volcanoes • Frost heave • Ocean currents ```

Question 350

There are 3 types of fires, surface, crown, and ground fires. Describe surface fires in terms of what conditions cause it to occur, and what are the consequences? Are there benefits?

Answer 350

* Only occurs if moisture is moderate before the fire, and wind conditions are moderate during the fire * May kill thin-barked trees if it gets hot enough, but doesn’t destroy mature forest * Thins out forest – kills some saplings, shrubs, herbs, & weaker trees * reduces combustible fuels, decreasing chance of future fires

Question 351

Benthic-pelagic coupling is crucial for energy cycling. | Ice algal primary production contributes __ - __% depending on area.

Answer 351

Ice algal primary production contributes 3 - 60% depending on area.

Question 352

List the 2 hypothesis for extinction in the Pleistocene (it was likely a combination of both causing it).

Answer 352

1. Glaciation-induced climate change. | 2. Introduced species - "overkill" by human hunters.

Question 353

Describe this quality of snow cover that affects living organisms: Thickness. How does it vary?

Answer 353

How deep the snow is – critical habitat for small mammals • Varies by latitude, regional climate, moisture, elevation

Question 354

* Reading by Carlson + Windsor* | - How does glacial melting influence sea level?

Answer 354

Ice melting can cause rapid oscillations (both increases and decreases) in sea level.

Question 355

Describe this Milankovitch cycle explaining changes in insolation reaching earth: - Precession. - How does it vary, and how long is the cycle?

Answer 355

- Earth wobbles as it rotates, causes different North Star. | - 26k period.

Question 356

How does a low-severity fire encourage or prevent further fires? How does it influence other tree/ plant life?

Answer 356

* May kill most of the vegetation but removed little of the standing biomass... * The high fuel load now increases the risk of another more severe fire. * Thick (> 1 meter) mats of sphagnum moss can protect the soil from high severity burns * The resulting postfire forest floor mosaic limits the recolonization of black spruce seedlings to areas of highest severity and shallowest remaining organic layer

Question 357

What are some human causes of disturbances? There are 6, list 4.

Answer 357

``` Human-caused: • Mining • Agriculture • Logging • Urbanization • Road construction • Ecotourism ```

Question 358

How can boreal forest "seed banks" promote growth?

Answer 358

Some understory plants survive as seeds buried in the soil for decades only germinate when canopy & leaf litter removed by fire.

Question 359

Once polar darkness sets in, autotrophic community members must employ survival tactics. How do sea ice diatoms survive?

Answer 359

Sea ice diatoms likely use a combination of facultative heterotrophy, a reduced metabolic state, and utilization of intracellular energy stores as well as previously released exopolymeric substances.

Question 360

What is the length of fire cycles controlled by? In boreal forests, are older trees more or less flammable?

Answer 360

* Length of the cycle controlled by moisture balance * Precipitation vs. evapotranspiration * Most boreal forests equally flammable regardless of age (after first decade)

Question 361

How long ago did this ice age occur? | - 5/5: Quatenary

Answer 361

2.6 million years ago to present.

Question 362

What are hyaline cells in sphagnum? What does this cause (that's potentially harmful)?

Answer 362

Hyaline cells – water-storage facilities Also responsible for acidification – inner surfaces are lined with positively charged hydrogen ions • released whenever another positive ion bonds in its place (creates acid) - This ion exchange removes nutrients, acidifies the site, and inhibits decomposition. - The pH of the water of Sphagnum bog may range from 3.7 to 4.9 (Parihar 1965)

Question 363

How big of an area do black and white spruce span in North America, and what layer (+depth) can they grow in? Do they dominate? Do they grow in wet or dry areas (drainage)?

Answer 363

Black spruce and white spruce are transcontinental – Very shallow root systems, can grow in an active layer only 25 cm thick. Dominate northernmost part, south of treeline. Black spruce grow in poorly drained low lying areas, while the white spruce is in well-drained, dry uplands.

Question 364

Do bogs or fens have more plant species? Which one is more common?

Answer 364

The total number of plant species is greater in fens | than in bogs – bogs are more widespread

Question 365

What does the emerald ash borer do to trees? Can it be eradicated? How many trees could it kill in the next 10 years?

Answer 365

Beetle that girdles tree – removes bark - Nothing can be done once infested - First found in Windsor, ON in 2002 - Winnipeg – fall 2017 Could kill up to 350,000 ash trees in next 10 years -Injected with insecticide to slow infestation

Question 366

Vegetation patterns exist in the tundra. Describe: Polar steppe

Answer 366

Polar steppe – similar to fell field, but on dry fine-grained soil, silt or sand (not gravel, rock or rubble). Vegetation more complete; most plants herbaceous • Dry, turfy appearance.

Question 367

How can movements from refugia be mapped?

Answer 367

Pollen records - pollen grains washed or blown into lakes acclimate in sediments and provide a record of past vegetation (reflecting climate conditions favourable for that vegetation).

Question 368

To stay alive in cold, life has a few options: Stay above 0C, or drop below 0C. In terms of staying above 0C, describe migration.

Answer 368

Go to warmth and food • Large mammals • Birds • Monarch Butterflies

Question 369

Describe this principle force acting on sea ice: - Internal Ice Stress

Answer 369

measure of the compactness, or strength, of the ice – most variable • resistance to the motion caused by the wind force • minimal when the sea ice pack is loosely compacted and can flow freely (e.g., in summer), but can be high when the ice is compact and cannot flow • plays an important role in the deformation of the ice and → in the formation of some features, e.g., ridges and leads. • strength of ice depends primarily on its thickness. Thin ice breaks apart easily under compression

Question 370

Phytoplankton blooms happen during and after sea ice breakup (after ice algae blooms). How do the phytoplankton blooms influence other life? • How is a warming climate changing this phenology?

Answer 370

* That large amount of energy drives productivity at surface | * Predators and in turn, their prey follow

Question 371

Are equilibriums ever reached indefinitely?

Answer 371

There are usually ups and downs constantly (if you graphed one parameter, it would look like waves).

Question 372

Lake Winnipeg is an example of a eutrophic lake. What nutrient causes algal blooms and where does it come from?

Answer 372

* Algal blooms in Lake Winnipeg are associated with both point source and non-point source phosphorus loading (non point source = from a distance away) * Large increases in blooms since 1990 are related to land-use and higher than normal precipitation associated with climate change (washes it into lake)

Question 373

How does the slope of RMR vary for tropical vs arctic animals?

Answer 373

Slopes are steeper for tropical – use a lot more energy at lower temps than Arctic mammals

Question 374

What part of trees are good for fire resistance? List 3 species with good resistance.

Answer 374

- Tree bark is protective. | - Paper birch, black spruce, jack pine.

Question 375

In terms of boreal forest fires; Why no change in mean fire size over time?

Answer 375

recently burned areas are less likely to burn again for a long time because of the decrease in fuel load

Question 376

As the earth orbits, it stays tilted in the same direction. When it's tilted toward the sun, it's ____. When it's tilted away from the sun, it's ____.

Answer 376

summer, winter.

Question 377

Vegetation patterns exist in the tundra. Describe: Shrub tundra

Answer 377

Shrub tundra - Low Arctic, vegetated with willow, dwarf birch, and heath

Question 378

What's the rule of 5 in terms of bulk salinity and brine volume?

Answer 378

At approximately -5 °C, bulk salinity of 5, brine volume is 5% = liquid permeable - the bottom of sea ice (above 5% brine) can flow and exchange water and other stuff. Below 5%, sea ice can't move. - Without the movement, there's limited access to important nutrients for primary producers.

Question 379

Constructive and destructive metamorphism occur simultaneously... which of these would occur in this scenario? New snow – _____ tends to be more common. Old snow – _____ tends to be more common.

Answer 379

New snow – destructive tends to be more common. | Old snow – constructive tends to be more common.

Question 380

Variety of adaptation mechanisms exist in the sea ice atmosphere. Exopolymeric Substances (EPS) produced by sea ice diatoms and bacteria are one, describe how they fit these 3 mechanisms: 1. Extracellular 2. Internal and Intracellular 3. Behavioural

Answer 380

1. Alter physical environment (can drill holes, make their own environment; EPS-clogging of brine channels can reduce brine drainage, increasing local brine salinities – increases habitat space via depression of freezing point) 2. Support adhesion and locomotion 3. Buffer and protect against extreme physicochemical conditions (defines against bacteriophages)

Question 381

Albedo is much higher in sea ice due to the numerous impurities found in sea ice (_____ growth) compared to lake ice (____ growth).

Answer 381

Albedo is much higher in sea ice due to the numerous impurities found in sea ice (lamellar growth) compared to lake ice (planar growth).

Question 382

Describe Taiga snow in terms of: - General description - Snow depth - Layers of snow

Answer 382

Thin-moderate, in trees, deep depth hoar - Snow depth: 30-120 cm - Layers of snow: >15

Question 383

What is a disturbance?

Answer 383

Relatively discrete event in time and space that alters the structure of populations, communities, and ecosystems and/or changes resources, substrate availability, or the physical environment.

Question 384

Ice melts when the temperature rises to __°C – the melting point.

Answer 384

Ice melts when the temperature rises to 0°C – the melting point.

Question 385

What does it mean that Canada is the "World's Waterkeeper"?

Answer 385

Canada houses more surface water than any other country.

Question 386

Define: Growing season.

Answer 386

period in the year during which temperatures are high enough for photosynthesis

Question 387

What is benthic-pelagic coupling? Why is it important?

Answer 387

exchange of energy, mass, or nutrients between benthic and pelagic habitats – crucial for energy cycling

Question 388

How long ago did this ice age occur? | - 4/5: Karoo

Answer 388

360-260 million years ago.

Question 389

* Reading by Warwick * In terms of the ecological implications of changes in the arctic cryosphere, what effect does the warming arctic cryosphere have on: Glaciers and ice shelves. - Benthic organisms, new/ invasive /extinctions of species, human impacts (fisheries), terrestrial environment (temperature effects).

Answer 389

- Glaciers and ice shelves provide a habitat for microbial communities and water supplies for streams, rivers, wetlands, and the coastal ocean. - Increased melting may stimulate benthic diversity, and open up new terrestrial habitats for microbes, and plants. - Once much of the water input is gone, the cold water species will likely die off, and warm-water taxa will invade. - Potential effects on currents, nutrient supply, marine productivity, fisheries, loss of habitats for marine birds and mammals, changes in coastal environments. - Can cause faster warming of terrestrial environments.

Question 390

There are 3 types of fires, surface, crown, and ground fires. Describe crown fires in terms of what burns, and how they form.

Answer 390

Crown fires – surface fire builds up enough heat to ignite the canopy • common in boreal forests, rare in deciduous forests • depends on tree canopy architecture & understory vegetation

Question 391

Related to sea surface tilt, what's a Geoid?

Answer 391

• Geoid – undulating surface results from the uneven distribution of mass within and on the surface of Earth

Question 392

Describe this area within the boreal zone in terms of trees (basic): Taiga.

Answer 392

boreal or northern coniferous forest

Question 393

Describe this layer of a nivean environment, and give an example of an animal that may live here. - Subnivean

Answer 393

below the snow • On land, created in area of depth hoar or pukak • On ocean, area where ice and snow meet • Denning area for ringed seals

Question 394

Define: Moraine.

Answer 394

Accumulation of glacial debris at the edge of a glacier.

Question 395

Radiant energy from the sun warms the earth's atmosphere and surface (water and soil) and becomes heat energy. List the 3 mechanisms by which energy is transferred through the atmosphere.

Answer 395

1. Conduction. 2. Convection. 3. Radiation.

Question 396

Conifers dominate the taiga for many reasons, describe how their short growing season contributes.

Answer 396

• Short growing season, but even shorter for deciduous species • Conifers photosynthesize whenever weather is warm enough. • Not as efficient at photosynthesis as broadleaf plants, but don’t have to be – don’t grow new leaves • Accumulator species – hoard minerals

Question 397

* Reading by Warwick * In terms of the ecological implications of changes in the arctic cryosphere, what effect does the warming arctic cryosphere have on: Water. - Plants, lakes/water bodies, animals, fish.

Answer 397

- Water availability is what limited northward progression of the treelike, not temperature. The tree lines will colonize where is there is enough moisture (non-uniformly), and can shift water balance, causing lakes and wetlands to dry up. - Snow banks are an important source of water for wetlands, and decreasing snow duration can ruin this. - The degradation of permafrost soils can result in the collapse, drainage, and complete disappearance of water bodies. - Warmer temperatures will cause rain instead of snow, which favours growth of broadleaf over conifer species, which decrease carbon storage, increase soil respiration, and decrease the timber potential of the forest. - Sudden rain can result in the rapid loss of protective snow, making vegetation vulnerable to freezing, and can prevent herbivores from accessing the (frozen) vegetation. - Changes in climate can change connectivity in bodies of water, which is problematic for migratory fish.

Question 398

Describe how peat can influence the amount of frozen ground present.

Answer 398

* found in marshy areas, partially decomposed dead plants - ground under peat is usually colder * Freezes in winter so allows heat to leave the ground * Dries in summer, insulates ground below * Land rises up because of peat plateaus (flat-topped) and palsas

Question 399

In terms of ice ages, what are "glacial"?

Answer 399

Pulses of cold periods.

Question 400

Frozen water expands 9% in volume, which injures | cells in 2 ways:

Answer 400

1) by rupturing the cell membranes | 2) by affecting the permeability of those membranes

Question 401

What is the subarctic in terms of: - How a climatologist would define the area (temp wise) - How a biologist would define the area (vegetation and permafrost or no frost)

Answer 401

* Tundra-Taiga zone * Climatologist: mean temp. >10C for < 4 mo. * Biologist: both forest and permafrost (continuous & discontinuous)

Question 402

What happens when permafrost melts in....? Tundra – Taiga –

Answer 402

Tundra – thermokarst lakes (soil collapses when permafrost or ice wedge thaws, creating a lake/marshy hollow) Taiga – drunken trees (trees displaced from their normal vertical alignment when permafrost melts)

Question 403

T/F - are drunken trees a sign of global warming?

Answer 403

T

Question 404

What proportion of trees in Alaska are showing signs of global warming, presenting as drunken trees? ``` 3-4% 5-6% 7-8% 9-10% 11-12% ```

Answer 404

7-8%

Question 405

Why can’t trees grow in the far north?

Answer 405

The lack of summer warmth – not cold winters. • Photochemical reactions (photosynthesis) can only happen if plant tissues are warm enough • Results in low growth Leaves and roots are a necessity; wood is a luxury

Question 406

___ are the most widespread peatlands in Canada, followed by ___

Answer 406

Bogs are the most widespread peatlands in Canada, followed by fens

Question 407

The total number of plant species is greater in ___ | than in ___, ___ are more widespread

Answer 407

The total number of plant species is greater in ____ | than in ___, ___ are more widespread

Question 408

____ – responsible for most of the organic buildup in the extensive peatlands of the north.

Answer 408

Sphagnum – responsible for most of the organic buildup in the extensive peatlands of the north.

Question 409

Most arctic sea ice is now

Answer 409

1

Question 410

How do cold temperatures affect animals? As in, what 3 main challenges do they face?

Answer 410

1. Food scarcity – plants die off or buried and endotherms need more food to burn for heat production. 2. Metabolism disrupted 3. Freezing. Ice crystals cause damage. Cells dehydrate.