Effects of Lengthening Growing Season and Increasing Temperature on Soil Carbon Fluxes and Stocks in Arctic Tundra

This one-year pilot project supports PI to test a new soil respiration measurement method and the possibility to manipulate temperature in the Arctic tundra. We warmed the tundra ecosystems with open-top chambers, conducted trenching experiment, and measured soil respiration with the continuous CO2 profile system.

Our preliminary data show that the tundra can be effectively warmed by our designed open-top chambers to an average of 0.3-3.1°C above the control plots. The CO2 sensors buried in soils can be effectively used to measure CO2 concentration and CO2 fluxes in the tundra. Our preliminary results indicated that soil respiration varied between 1.0 and 2.5 μmol m-2s-1 with a distinct diel pattern in the summer. Total ecosystem respiration ranged from 4 to 6 μmol m-2s-1, indicating that aboveground plant respiration (leaf and stem) accounted for more than half of the total respiration. The trenching experiment enables us to examine the difference of soil respiration and its temporal pattern between plots with roots and without root influence. Tang has submitted a renewal proposal to NSF to continue this soil respiration project in the Arctic tundra.