Carbon Cycling at High Latitudes Flashcards
What are the main land covers of high latitudes?
Boreal forests: coniferous, freezing temps for 6-8 months
Arctic tundra: treeless, beyond northern tree limit. Grasses, sedges and shrubs.
What are characteristics of high latitude ecosystems?
- Cold, so slow decomposition
- Short growing season, low nutrients
- Snow cover, freezing tolerance
- Store lots of carbon underground
What is NPP?
Net primary productivity
NPP = GPP - R
What is NEP?
Net ecosystem productivity
NEP = NPP - Reco
How much carbon do boreal forests store in soil?
2-3 times more C in soil than in biomass
How much carbon does tundra store in soil?
5 times more C in soil than in biomass
Is the turnover time short or long for high latitude ecosystems?
highest turnover time, keep molecule of carbon in ecosystem for the longest until it is released.
What has changed about the growing season in high latitudes and how do we know?
NDVI shows growing season in longer, meaning productivity is going up and there is more carbon gain in plants.
What is happening to the boreal treeline?
How do we know?
It is advancing onto tundra (northward)
There are more young trees at the edge of the tree line and more seedlings.
How much shrubification has there been on the hill tops?
Abundance has increased by 28% on the hilltops.
What do models predict about soil decomposition?
If there is more C in biomass, there will be more C removal from the atmosphere, meaning more C is in the soil. However this could cause priming of decomposition and carbon loss.
What is priming of decomposition?
Input of new carbon into the soil stimulates decomposition of old soil carbon.
What is a trade off to do with warming of high latitudes?
Warming will also increase respiration and soil respiration, meaning soil C storage might not increase.
