Vegetation Disturbance Triggers Greenhouse-Gas Emitting Feedback Loop in Permafrost

by Lindsay McCord

Vegetation changes have the ability to rapidly destabilize permafrost soil, illustrating vulnerability of these ecosystems to disruptions. Study sites that removed shrub vegetation experienced both increased thaw depth of permafrost as well as soil subsidence, lowering the permafrost table by 31 cm in comparison to control sites. This created localized wetlands of water-saturated depressions, which become hotspots for additional thawing as well as increased methane emissions. Continue reading

Modeling CO2 and CH4 Fluxes in the Arctic using Satellite data

by Rebecca Herrera

The peatlands and tundras of the Arctic perform vital ecosystem services to the earth through their ability to sequester carbon (CO2) and methane (CH4) and function as a carbon sink. The ability of the permafrost in the peatlands and tundra ecosystems of the Arctic to continue to function as a natural reservoir for carbon and methane may be disrupted by rising global temperatures that increase the rate of soil decomposition. Watts et al. (2014) integrate a terrestrial carbon flux (TCF) model to include a newly developed CH4 emissions algorithm. The new TCF model simultaneously assesses CO2 and CH4 fluctuations and the corresponding net ecosystem carbon balance (NECB), which is contingent upon gross primary productivity (GPP) subtracted from ecosystem respiration. The integrated TCF model uses data gathered through satellite remote sensors to assess fluxes in CO2 and CH4. Continue reading