Grasslands

Question 1

What is Grassland health underpinned by?

Answer 1

C cycling throughout food web, mediating energy flow and biogeochemical cycles

Question 2

How much terrestrial stock in grasslands?

Answer 2

25-34%

Question 3

What is C cycle regulated by?

Answer 3

Carbon in carbon out, with grasslands more exposed to abiotic factors

Question 4

Where do grasslands occur?

Answer 4

Evaporation exceeds precipitation or soils to shallow to suport woody plants

Question 5

Grassland temporal C cycle

Answer 5

Greater inter/intra annual C cycle determined by physiological response and climate

Question 6

Terrestrial Grassland Community

Answer 6

Short lived herbaceous plants dominate producing lower lignin thus transient biomass C pool

Question 7

How much C do grasslands store?

Answer 7

525-634 Pg C wiht 80-94% being soil, rest being biomass

Question 8

What are grassland C stocks most influenced by?

Answer 8

Plant diversity positively affected SOC accumulation

Question 9

What is an example of importance of succession in GL C?

Answer 9

Cedar Creek meant SOC accumulation 2x greater after 13-22 years than at time of establishment

Question 10

How does plant diversity influence GL soil?

Answer 10

Enhance soil microbial community critcial as fungi/bacteria primary decomposer organisms in soilW

Question 11

What are the most important decomposers?

Answer 11

Bacteria due to the labile litter with lower C-N ratios and lower lignin

Question 12

Bacteria/Fungi contribution to C stock

Answer 12

2-3x higher than forest soils due to plantlitter promoting microbial C use

Question 13

How does solar interact with grasslands?

Answer 13

Light photo-oxidation in more sunlight-exposed grasslands

Question 14

Photodecomposition

Answer 14

Process of light absorbing molecules like lignin and polyphenols capture solard radiation degrading into CO, CO2 and CH4

Question 15

Photopriming Effect

Answer 15

Where litter becomes more susceptible to microbial degradation under humid conditions

Question 16

How extensive can photopriming effect be?

Answer 16

Breaking recalcitrant compounds like lignin, cellulose, and hemicellulose

Question 17

How does wind impact grasslands?

Answer 17

Clay and silt selectively removed and transported over long distances, and are enriched with C

Question 18

How does precipitation impact GL?

Answer 18

Increased NEP by 33%, strong on aboveground biomass with limited impacts on root and total biomass

Question 19

How does N addition impact?

Answer 19

Reduced plant C quality, increased calcitrant C, increased POM-C (more sensitive to global change than MAOM)

Question 20

Why is POM-C less important for long term storage?

Answer 20

More susceptible to grazing and disturbance.

Question 21

How does UN defined sustainable food system?

Answer 21

Delivering food security and nutrition, that the economic, social, and environmental bases to generate food security and nutrition for future generations is not compromised.