Moss cover induced cooler soil temperature limits carbon flux of a Siberian tundra
|Session Name||5.20 Open science session|
|Location||Tellus Arena, Tellus Innovation Arena|
|Author(s)||Hotaek Park (JAMSTEC, Japan), Samuli Launiainen (Natural Resources Institute Finland, Finland)|
In the Arctic terrestrial regions, mosses strongly affect water and heat fluxes due their high water holding capacity and insulation. A land surface model, CHANGE, was used to quantitatively assess the influences of moss cover on soil temperature (TSOIL), active layer thickness (ALT), and carbon flux feedback. The CHANGE model was coupled with a moss process module, explicitly representing heat, water, and carbon exchanges in the atmosphere–vascular plants–moss–soil system. The model was applied to a tundra site in northeastern Siberia over the period of 1980–2013. The simulated results indicated that the moss resulted in warmer winter and cooler summer TSOIL, thus lowering the ALT. This feature of moss cover was validated by model experiments that controlled the thickness and fractional surface coverage of the moss layer. The moss-induced cooler TSOIL could limit ecosystem carbon assimilation by reducing water availability to plant roots due to the presence of ice. This limitation increased with moss layer thickness and coverage. Our modeling study suggests that moss has a significant impact on TSOIL, ALT, and carbon flux in Arctic tundra and may play an important role in future Arctic warming.