| Summary: | We deployed the FD chamber system in a tundra ecosystem over the discontinuous permafrost regime of Council, Alaska. The representative understory plants are tussock (17 %), lichen (32 %), and moss (51 %), within a 40 × 40 m plot at an interval of five meters (81 points total) for efflux-measurement by dynamic chamber. The FD chamber monitored soil CO2 effluxes from moss, lichen, and tussock regimes at an interval of 30 min during the growing season of 2015. As the results, mean soil CO2 effluxes in intact and infected sphagnum moss, lichen, and tussock were 0.42 ± 0.17, 0.39 ± 0.22, 0.76 ± 0.21, and 0.87 ± 0.41 ?mol/m2/s during June 25 to September 21 2015, respectively. Mean simulated soil CO2 efflux normalized by air temperature of 10°C were 0.40 ± 0.17, 0.36 ± 0.16, 0.77 ± 0.13, and 0.85 ± 0.30 ?mol/m2/s from four plants, respectively, suggesting there are not significant differences between measured and simulated CO2 effluxes. During the measured air temperature from January 1 to October 3 2015, snow-covered (Jan 1 to May 8) and snow-free (May 8 to October 3) period carbon emission rates from intact and infected sphagnum, lichen, and tussock were 8.0, 6.9, 47.0, and 22.6 gC/m2/period, and 59.4, 53.4, 115.0, and 126.7 gC/m2/period. We found the snow-free period carbon contributes 88.1, 88.6, 71.0, and 84.8% of annual carbon emission rates from intact and infected sphagnum, lichen, and tussock, respectively.
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