Disentangling the Effects of Climate, Vegetation, Soil and Related Substrate Properties on the Biodegradability of Permafrost-Derived Dissolved Organic Carbon

作  者:Liu FT, Kou D, Abbott BW, Mao C, Chen YL, Chen LY, Yang YH*
影响因子:3.621
刊物名称:Journal of Geophysical Research-Biogeosciences
出版年份:2019
卷:  期:  页码:DOI:10.1029/2018JG004944

论文摘要:

Dissolved organic carbon (DOC) plays an important role in permafrost carbon cycle. However, substantial uncertainties remain about what determines the biodegradability of permafrostderived DOC and how the biodegradability varies between permafrost and activelayer soils at a regional scale. Here, we conducted an incubation experiment with DOC leached from permafrost and activelayer soils along a ~1,000km permafrost transect on the Tibetan Plateau. Our results showed that permafrostderived DOC had high biodegradability, with an average of 21.7% loss of DOC over a 28day incubation. The biodegradability of DOC leached from permafrost soils was larger than or equal to that in activelayer within 72% of sampling sites. Our results also revealed that variation in DOC biodegradability in permafrost soils and its difference with that in activelayer soils were jointly determined by vegetation types, soil properties, and related DOC composition. The biodegradability of permafrostderived DOC in alpine steppe and meadow was lower than that in swamp meadow. It also declined with the decreasing soil carbon: nitrogen ratio, increasing pH, clay content, DOC molecular weight, and its degradation degree. Similarly, the variability in the difference of DOC biodegradability between permafrost and activelayer soils also resulted from the differences of three types of abovementioned factors between the two layers. These results suggest that permafrost thawinginduced DOC release could intensify permafrost carbonclimate feedback due to its vulnerability to microbial decomposition, with its impact depending on vegetation, soil, and substrate properties.

全文链接:https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2018JG004944