Lecture 3 - Soils and Peatlands

Question 1

Soil

Answer 1

the upper layer of the geosphere, consisting of:

• mineral grains, organic matter, pore spaces filled with gases and/or water, as well as any biota found there

Question 2

Mineral Soil

Answer 2

predominantly mineral grains (<5% organic matter)

Question 3

Hydric Soils

Answer 3

soils that form under conditions of saturation, flooding or ponding long enough during the growing season to develop anaerobic conditions in the upper part

• can be mineral or organic

Question 4

Hydric Mineral Soils

Answer 4

<20 or 35% organic matter

• found in marshes, swamps, open water wetlands

Question 5

Aerobic Respiration

Answer 5

the most efficient biological reaction to oxidize organic carbon compounds for energy

Question 6

Leaching

Answer 6

when ions that are very soluble in water move with the water as it flows through the soil and out of the system

Question 7

Gleying

Answer 7

grey colour in hydric mineral soil caused by leaching

Question 8

E Layer of Soil

Answer 8

eluviated zone, where gleying occurs

Question 9

Mottles in Hydric Soil

Answer 9

rusty red or black patches in soil caused by O2 penetrating soils and forming Fe2O3 or MnO2`

Question 10

Oxidized Rhizospheres

Answer 10

pore linings around the roots of a wetland plant caused by the transport of excess oxygen by wetland plants to their roots

Question 11

Hydrogen Sulfide

Answer 11

(H2S) a toxic gas, smells like rotten eggs

Question 12

Soil Texture

Answer 12

the distribution of mineral grain sizes

Question 13

Capillary Water

Answer 13

water held by capillary forces to mineral grains (H-bonding)

Question 14

Clay Minerals

Answer 14

sheet silicate minerals formed only by weathering (cations between the sheets, with Si and O ions forming the sheet structures)

Question 15

Cation Exchange Capacity

Answer 15

(CEC) the ability of soils to store and release cations

• when dissolved cations come into contact with clays, they will absorb to the surface, releasing H+ (or another cation)

Question 16

Organic Soils

Answer 16

soils that are rich in organic matter (OM)

> 20-35% organic matter as dry weight

or >10-18% organic carbon

Question 17

Bulk Density

Answer 17

dry weight of soil material/volume

Question 18

Hydraulic Conductivity (K)

Answer 18

water velocity/hydraulic gradient, a measure of how quickly water moves through soil

Question 19

Nutrient Availability

Answer 19

organic soils often have nutrients in organic molecules that are difficult to break down

Question 20

Types of Organic Soils

Answer 20

saprist, fibrist, hemist, folist

Question 21

Saprist Soils

Answer 21

(muck), > 2/3 of the material is decomposed, > 1/3 of plant fibres are dientifiable

Question 22

Fibrist Soils

Answer 22

(peat), > 1/3 of material decomposed

Question 23

Hemist Soils

Answer 23

(mucky peat), between saprist and fibrist

Question 24

Folist Soils

Answer 24

organic soils caused by excessive moisture in mountains, not hydric soils because saturated conditions are not common

Question 25

Acrotelm

Answer 25

layer containing living stems and roots (usually to depth of water table)

Question 26

Catotelm

Answer 26

below water table, slow anaerobic decay

Question 27

Peatlands

Answer 27

any wetlands with peat (bogs, fens, sometimes marshes and swamps)

Question 28

Terrestrialization

Answer 28

in-filling shallow lakes

Question 29

Paludification

Answer 29

blanketing of terrestrial ecosystems with peatland

Question 30

Quaking Bog Succession

Answer 30

in-filling quiet, shallow lake that forms floating peat mats and eventually a dome bog

Question 31

Poor Fens

Answer 31

low in nutrients and biodiversity (higher than bog)

Question 32

Rich Fens

Answer 32

higher nutrients and productivity than poor fens