Arctic Tundra - Carbon

Cards (11)

  • What are the characteristics of the Tundra's carbon cycle?
    • Permafrost is a big carbon sink - globally contains 1600 GT of carbon
    • Carbon accumulated due to low temperatures which slows decomposition of dead material
    • Carbon in soil is x5 greater than above ground
    • NPP is low - 200 grams/m2/year Small tundra biomass between 4-29 tonnes/ha
    • CO2 and methane are released from unfrozen soil and permafrost water in the winter
    • Global warming has reduced the permafrost's function as a carbon store. It is becoming a carbon source. However, warmer temperatures increase plant growth, increasing stores
  • How do the flows and stores vary in the Tundra's carbon cycle?
    • Carbon is stored as partly decomposed plant remains frozen in permafrost. Locked away for 500,000 years
    • Low temperatures and waterlogging slow decomposition and respiration and the flow of CO2 to the atmosphere
    • Low temperatures, lack of liquid water and rocks containing few nutrients = limited plant growth
    • Short growing season leads to low biomass carbon store
    • Rock composition has little influence due to permeability /porosity/mineral composition
  • What are some stores and flows in the Tundra?
    • Vegetation
    • Photosynthesis
    • Soil/ground
    • Atmosphere
  • How does the vegetation affect the Tundra's carbon cycle?
    Low Net Primary Productivity (200 grams/m2/yr)
    Low biomass
  • How does photosynthesis affect the Tundra's carbon cycle?
    • Sequestration of CO2 low
    • During summer there is rapid growth but still limited biomass for photosynthesis
  • How does soil/ground affect the Tundra's carbon cycle?
    • Permafrost stores vast amounts of carbon ; although accumulation is slow, there is 5x more carbon here than above ground
  • How does the atmosphere affect the Tundra's carbon cycle?
    • CO2 released into the atmosphere all year round but most during growing season via respiration
  • What are the physical factors affecting the Tundra's carbon cycle?
    • Geology
    • Temperature
    • Biomass
  • How does geology impact the Tundra's carbon cycle?
    • Little impact on flows of carbon cycle due to impermeability of the permafrost overlying hard crystalline rock
    • Most carbon stored in permafrost
  • How does temperature impact the Tundra's carbon cycle?
    • Low temperatures slow photosynthesis and respiration, so limited flow of CO2 to atmosphere
    • Slow decomposition
  • How does biomass impact the Tundra's carbon cycle?
    • Total store small due to limited water and sunlight