Antarctic soil fungal communities

Question 1

Define saprotrophy

Answer 1

Using dead plant material for energy
This includes most decomposers

Question 2

Describe two important characteristics of saprotrophs

Answer 2

Ability to penetrate the protective surface of material and ability to invade at a cellular and molecular level

Question 3

What organisms are the main decomposers of primary resources?

Answer 3

Saprotrophic fungi (chemoheterotrophs)

Question 4

What are saprotrophic fungi also responsible for?

Answer 4

They are the main producers of extracellular depolymerising enzymes

Question 5

Define mycelium

Answer 5

The collective term for hyphae
Hyphae and mycelium join to produce rhizomorphs

Question 6

What is mycelium used for?

Answer 6

Use by fungi for the translocation of nutrients between microsites

Question 7

What is mycelium important for?

Answer 7

The penetration and invasion of detrital materials

Question 8

Describe the circulation of nutrients in fungi

Answer 8

They have autolysis of their old compartments, the contents of a dead cell moves to the new growing tops of mycelium

Question 9

What is increased plant litter result in?

Answer 9

Increased species richness of saprotrophic fungi

Question 10

What are the four life strategies?

Answer 10

R-selected, K-selected, C-selected, S-selected

Question 11

Describe R-selected life strategy

Answer 11

Short life expectancy
Commit most resources to reproduction
Use readily available C sources

Question 12

Describe K-selected life strategy

Answer 12

Long life expectancy
Commit small proportion of resources to reproduce at any one time
Usually reproduce at end of life span

Question 13

Describe C-selected life strategy

Answer 13

Competitive strategy maximises ability to occupy and exploit resources in low stress/disturbance conditions

Question 14

Describe S-selected life strategy

Answer 14

Using a stress tolerant strategy to adapt to continuous environment stress

Question 15

What type of organisms use unicellular growth form?

Answer 15

Bacteria and yeast

Question 16

What are unicellular growth forms adapted to?

Answer 16

Surface of particular detritus where SA:V is high but not adapted to penetrate hard materials

Question 17

Describe the reproduction of unicellular growth forms

Answer 17

Rapid dispersal and reproduction, their small size allows them to colonise soil pores

Question 18

Describe the tolerance of unicellular growth forms

Answer 18

They are more tolerant of disturbance than mycelia (rhizomorphs aren’t very tolerant to disturbance)

Question 19

Why are bacteria and fungi successful?

Answer 19

Wide range of substrate utilisation and physiology, reproductive strategy, genetic adaptability (lots of different races)

Question 20

Describe the reproductive strategy of bacteria and fungi

Answer 20

Asexual conidia
Able to colonise new substrates

Question 21

What are the two flowering plants on continental Antarctica?

Answer 21

Antarctic pearlwort and Antarctic hair grass

Question 22

Why should Antarctic soil fungi be studied?

Answer 22

They probably dominate the decomposition process
Unsure how this will change with regional warming

Question 23

How could the role of Antarctic soil fungi change with regional warming?

Answer 23

Increased precipitation and increased vascular plant populations can lead to increased decomposition activity and therefore greater CO2 production

Question 24

How have Antarctic fungal communities been characterised?

Answer 24

Cultures and collections

Question 25

What is the problem with Antarctic fungal communities being characterised by cultures and collections?

Answer 25

They are based on fungal fruit bodies, but not all produce macroscopic fruit bodies that aren’t ephemeral (short-lived)

Question 26

How many species of lichenised fungi have been described in sub, maritime, and continental Antarctica?

Answer 26

~400

Question 27

Define lichens

Answer 27

Symbiosis between fungi (dominant partner) and algae

Question 28

How many non-lichenised fungi have been describe in Antarctica?

Answer 28

~1,000

Question 29

What factors influence the community assemblage of fungi?

Answer 29

Not known

Question 30

What are the conclusions of this study in relation to species richness?

Answer 30

Reduction in species richness as you move south

Question 31

What are the conclusions of this study in relation to basidiomycete fungi?

Answer 31

Smaller proportion of this type as you move south

Question 32

What are the conclusions of this study in relation to fungal community?

Answer 32

Antarctic fungi are similar to fungi in other cold places
Evidence for role of environmental filtering

Question 33

What were the methods for this study?

Answer 33

3 soil pits with horizontal cores at 3 depths per island
DNA extracts from each sample, amplified by PCR and sequenced using 454 pyrosequencing