Topographically regulated traps of dissolved organic carbon create hotspots of soil carbon dioxide efflux in forests

Autor: Kara L. Webster, G. L. Braun, Irena F. Creed, R. A. Bourbonniere, F. D. Beall
Rok vydání: 2012
Předmět:
Zdroj: Biogeochemistry. 112:149-164
ISSN: 1573-515X
0168-2563
DOI: 10.1007/s10533-012-9713-4
Popis: Soil carbon pools are an essential but poorly understood factor in heterotrophic soil respiration on forested landscapes. We hypothesized that the topographically regulated distribution of dissolved organic carbon (DOC) is the dominant factor contributing to soil CO2 efflux. We tested this hypothesis by monitoring soil CO2 efflux and sampling particulate and dissolved substrates (both mobile DOC in soil solution and DOC potentially sorbed onto Fe and Al oxyhydroxides) in surface (freshly fallen leaves (FFL) and forest floor) and near-surface (A-horizon or top 10 cm of peat) soils along three hillslope transects (15°, 25° and 35° slopes) that included upland (crest, shoulder, backslope, footslope, and toeslope) and wetland (periphery and central) topographic features during the snowfree season within a sugar maple forest. We observed that median snowfree season soil CO2 efflux ranged from 5 μmol CO2 m−2 s−1. Substrates in the near-surface mineral soil were most strongly related to median soil CO2 efflux, and when combined mobile DOC and sorbed DOC together explained 78% of the heterogeneity in median soil CO2 efflux (p
Databáze: OpenAIRE
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