Lecture 33. Terrestrial Ecosystems: Deserts, Tundra and Peatlands

Question 1

What are the two types of tundra ?

Answer 1

1. Alpine

2. Arctic

Question 2

What does descending dry air absorb ?

Answer 2

Moisture

Question 3

What does descending air cretae ?

Answer 3

Arid conditions

Question 4

What is desert location determined by ?

Answer 4

1. Global atmospheric circulation
2. Rain shadows
3. Continental interiors

Question 5

What are the two types of desert ?

Answer 5

1. Hot deserts

2. Cold deserts

Question 6

What are the physical characteristics of rainfall ?

Answer 6

1. Low and unpredictable rainfall - water lost quickly
2. High evaporation
3. Hot or cold temperature
4. Large diurnal variation in temperature

Question 7

In the desert how is water lost quickly ?

Answer 7

Evaporation and drainage

Question 8

What are some plant adaptations to desert ?

Answer 8

1. avoid drought by carefully timed phenology

Question 9

How can drought be tolerated ?

Answer 9

1. Intensification of water absorption

2. Reduce transpiration

Question 10

How may plants intensify water absorption ?

Answer 10

1. Shallow spreading roots - succulents
2. Deep roots-tap roots
3. Dew/fog traps

Question 11

How can transpiration be reduced ?

Answer 11

1. Sunken stomata
2. Reduced stomatal aperture
3. Scaly/hairy leaves
4. Folding/ rolling leaves
5. Retain dead leaves around stem
6. Deciduous- shed leaves/branches

Question 12

What percentage of water is absorbed by roots and is lost via stomata ?

Answer 12

95%

Question 13

What does CAM stand for ?

Answer 13

Crassulacean acid metabolism photosynthesis

Question 14

How does CAM work ?

Answer 14

Stomata are closed during day. Opened during night and organic acids are stored. During the day they are converted to carbon dioxide.

Question 15

What is the advantage of CAM ?

Answer 15

Increases photosynthesis and decreases transpiration

Question 16

What are the physical characteristics of tundra ?

Answer 16

1. Cold
2. Low precipitation
3. Permafrost
4. Short growing season

Question 17

What are the botanical characteristics of tundra ?

Answer 17

1. Diversity is low
2. Perennials with vegatative reproduction
3. Low in stature- no trees
4. Shallow rooting

Question 18

What are some examples of tundra plants ?

Answer 18

Grasses, mosses, heathers, lichens

Question 19

Why is tundra a low nutrient system ?

Answer 19

1. Low temperature and precipitation because of slow weathering and nitrogen fixation
2. Permafrost reduces depth of biologically active soil
3. Minimal input of nutrients from precipitation
4. Slow nutrient cycling

Question 20

What biome has the lowest nutrient cycling rates ?

Answer 20

Arctic

Question 21

What is peat ?

Answer 21

Partially decayed organic matter of plant origin formed under wet anaerobic conditions

Question 22

Where is peat distributed ?

Answer 22

Areas of high rainfall and impeded drainage

Question 23

Why are peatlands growing ?

Answer 23

The rate oof production of organic matter is greater than the decomposition carried out by detrovores

Question 24

What are the layers of a peatlands ?

Answer 24

1. Acrotetm
2. Water table
3. Catotelm

Question 25

How is hydrosere peatland formed ?

Answer 25

1. Lake 2. Reedswamp 3. Fen (minerotrophic) 4. Raised bog (ombotrophic)

Question 26

Other than hydrosere, how may a peatland form ?

Answer 26

1. Forest 2. Pasture arable - minerotrophic 3. Heath 4. Blanket bog - ombrotrophic

Question 27

What are the two types of bog ?

Answer 27

1. Raised bog | 2. Blanket bog

Question 28

Where are blanket bogs found ?

Answer 28

Regions where there is 1200mm rain and 200 rain days

Question 29

What is a downside to rain ?

Answer 29

Low dilute nutrient solution

Question 30

What is an ombotrophic bog system low in ?

Answer 30

1. Nutrients | 2. Bases

Question 31

What is the pH of fen ?

Answer 31

7

Question 32

What is the pH of bog ?

Answer 32

Less than 4

Question 33

What are the characteristics of ombotrophic bogs ?

Answer 33

1. Low in nutrients 2. Waterlogged 3. Acidic

Question 34

What are plant strategies for ombrotrophic bogs ?

Answer 34

1. Mycorrihaze 2. Efficient recycling 3. Xeromorphs 4. Carnivorous habitat 5. Effective ion exchange

Question 35

What can peatlands be exploited for ?

Answer 35

1. Fuel 2. Horticulture 3. Waste water treatment 4. Forestry 5. Agriculture

Question 36

What are the advantages of peatlands ?

Answer 36

1. Wildlife habitat 2. Regional water table 3. Landscape/tourism 4. Archives 5. Carbon sink

Question 37

What is permafrost ?

Answer 37

Permafrost is any ground that remains completely frozen—32°F (0°C) or colder—for at least two years straight.