科研之友
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摘要
Soil CH(4) and CO(2) gas contents were determined at 39 sites located along the 1957 km coastline of the Beaufort Sea of northern Alaska. Average soil CH(4) concentrations increased with depth into the upper frozen layers, while the CO(2) decreased with depth. Over 80% of the CH(4) and 46% of the total CO(2) were contained in the permafrost portion of the profiles. Overall, average concentrations of CH(4) within the soil profiles were correlated to water content (R(2) = 0.66, p <= 0.01). Concentrations of CO(2) were correlated to total organic carbon (R(2) = 0.76, p <= 0.001) and negatively correlated to water content (R(2) = 0.61, p <= 0.01). The highest total bank gas concentrations for both gases were found in ice-rich permafrost (average volumetric H(2)O >= 70%). Soils eroded across the coast annually were estimated to contain 3.61 +/- 1.35 t CH(4) (average 1.86 +/- 0.70 g m(-2)) and 469 +/- 128 t CO(2) (average 240 +/- 65 g m(-2)). Gas amounts present in annually eroding banks were on the same order of magnitude as amounts emitted per year on an area basis from undisturbed tundra and lakes reported by others for the Arctic and smaller than previous estimates for local coastal anthropogenic sources. Soil stocks of gases, water and total organic carbon indicate that with coastal permafrost degradation gas release is minor in magnitude and importance to C-dynamics when compared to the TOC stocks of the coastline.
- 出版日期2011-3-4
