Permafrost Flashcards
What is permafrost
How much carbon does it store?
Permanently frozen ground, mostly as high latitudes.
Stores twice as much carbon than the atmosphere.
What is the active layer?
The portion of soil above permafrost that thaws and freezes seasonally.
What is happening to the active layer as a result of climate change?
It is thickening and deepening, which exposes more carbon to decay that was previously preserved in permafrost.
What are the main ecosystem controls of active layer thickness?
What do they do for permafrost?
- Dry soil
- Tree canopy cover (evergreen trees)
- Moss cover
- Shrub cover
They protect permafrost by promoting shallow active layer thickness.
How does fire affect active layer thickness?
Fire causes deepening of the active layer, as it takes away the permafrost protecting ecosystem characteristics.
What is the most effective ecosystem characteristic for shallow and deep slopes (in terms of active layer thickness)?
On shallow slops: soil organic layer is most controlling of ALT
On steep slopes: there is better drainage, soil is dryer so there is less need for insulation of organic layer.
What do drier soils mean for active layer thickness?
In dry soils, tree canopy cover is less important, because there is already dry soil
What are thermokarst wetlands?
When permafrost thaws, thermokast wetlands are produced.
They cause large increases in CH4 release.
How much CH4 released in thermokarst wetlands comes from old carbon that was stored in permafrost?
8%
