Antarctic soil fungal communities Flashcards
Define saprotrophy
Using dead plant material for energy
This includes most decomposers
Describe two important characteristics of saprotrophs
Ability to penetrate the protective surface of material and ability to invade at a cellular and molecular level
What organisms are the main decomposers of primary resources?
Saprotrophic fungi (chemoheterotrophs)
What are saprotrophic fungi also responsible for?
They are the main producers of extracellular depolymerising enzymes
Define mycelium
The collective term for hyphae
Hyphae and mycelium join to produce rhizomorphs
What is mycelium used for?
Use by fungi for the translocation of nutrients between microsites
What is mycelium important for?
The penetration and invasion of detrital materials
Describe the circulation of nutrients in fungi
They have autolysis of their old compartments, the contents of a dead cell moves to the new growing tops of mycelium
What is increased plant litter result in?
Increased species richness of saprotrophic fungi
What are the four life strategies?
R-selected, K-selected, C-selected, S-selected
Describe R-selected life strategy
Short life expectancy
Commit most resources to reproduction
Use readily available C sources
Describe K-selected life strategy
Long life expectancy
Commit small proportion of resources to reproduce at any one time
Usually reproduce at end of life span
Describe C-selected life strategy
Competitive strategy maximises ability to occupy and exploit resources in low stress/disturbance conditions
Describe S-selected life strategy
Using a stress tolerant strategy to adapt to continuous environment stress
What type of organisms use unicellular growth form?
Bacteria and yeast
What are unicellular growth forms adapted to?
Surface of particular detritus where SA:V is high but not adapted to penetrate hard materials
Describe the reproduction of unicellular growth forms
Rapid dispersal and reproduction, their small size allows them to colonise soil pores
Describe the tolerance of unicellular growth forms
They are more tolerant of disturbance than mycelia (rhizomorphs aren’t very tolerant to disturbance)
Why are bacteria and fungi successful?
Wide range of substrate utilisation and physiology, reproductive strategy, genetic adaptability (lots of different races)
Describe the reproductive strategy of bacteria and fungi
Asexual conidia
Able to colonise new substrates
What are the two flowering plants on continental Antarctica?
Antarctic pearlwort and Antarctic hair grass
Why should Antarctic soil fungi be studied?
They probably dominate the decomposition process
Unsure how this will change with regional warming
How could the role of Antarctic soil fungi change with regional warming?
Increased precipitation and increased vascular plant populations can lead to increased decomposition activity and therefore greater CO2 production
How have Antarctic fungal communities been characterised?
Cultures and collections
What is the problem with Antarctic fungal communities being characterised by cultures and collections?
They are based on fungal fruit bodies, but not all produce macroscopic fruit bodies that aren’t ephemeral (short-lived)
How many species of lichenised fungi have been described in sub, maritime, and continental Antarctica?
~400
Define lichens
Symbiosis between fungi (dominant partner) and algae
How many non-lichenised fungi have been describe in Antarctica?
~1,000
What factors influence the community assemblage of fungi?
Not known
What are the conclusions of this study in relation to species richness?
Reduction in species richness as you move south
What are the conclusions of this study in relation to basidiomycete fungi?
Smaller proportion of this type as you move south
What are the conclusions of this study in relation to fungal community?
Antarctic fungi are similar to fungi in other cold places
Evidence for role of environmental filtering
What were the methods for this study?
3 soil pits with horizontal cores at 3 depths per island
DNA extracts from each sample, amplified by PCR and sequenced using 454 pyrosequencing
