Interactive Effects of Climate Change and Decomposer Communities on the Stabilization of Wood-Derived Carbon Pools: Catalyst for a New Study

doi:10.2172/1163911

GSTDTAP > 地球科学

DOI	10.2172/1163911
报告编号	DOE-MTU--0006986
来源ID	OSTI ID: 1163911
	Interactive Effects of Climate Change and Decomposer Communities on the Stabilization of Wood-Derived Carbon Pools: Catalyst for a New Study
	Resh, Sigrid C.
	2014-11-17
出版年	2014
页数	15
语种	英语
国家	美国
领域	地球科学
英文摘要	Globally, forest soils store ~two-thirds as much carbon (C) as the atmosphere. Although wood makes up the majority of forest biomass, the importance of wood contributions to soil C pools is unknown. Even with recent advances in the mechanistic understanding of soil processes, integrative studies tracing C input pathways and biological fluxes within and from soils are lacking. Therefore, our research objectives were to assess the impact of different fungal decay pathways (i.e., white-rot versus brown-rot)âin interaction with wood quality, soil temperature, wood location (i.e., soil surface and buried in mineral soil), and soil textureâon the transformation of woody material into soil CO₂ efflux, dissolved organic carbon (DOC), and soil C pools. The use of ¹³C-depleted woody biomass harvested from the Rhinelander, WI free-air carbon dioxide enrichment (Aspen-FACE) experiment affords the unique opportunity to distinguish the wood-derived C from other soil C fluxes and pools. We established 168 treatment plots across six field sites (three sand and three loam textured soil). Treatment plots consisted of full-factorial design with the following treatments: 1. Wood chips from elevated CO₂, elevated CO₂ + O₃, or ambient atmosphere AspenFACE treatments; 2. Inoculated with white rot (Bjerkandera adusta) or brown rot (Gloeophyllum sepiarium) pure fungal cultures, or the original suite of endemic microbial community on the logs; and 3. Buried (15cm in soil as a proxy for coarse roots) or surface applied wood chips. We also created a warming treatment using open-topped, passive warming chambers on a subset of the above treatments. Control plots with no added wood (âno chip controlâ) were incorporated into the research design. Soils were sampled for initial Î´¹³C values, CN concentrations, and bulk density. A subset of plots were instrumented with lysimeters for sampling soil water and temperature data loggers for measuring soil temperatures. To determine the early pathways of decomposition, we measured soil surface CO₂ efflux, dissolved organic C (DOC), and DO¹³C approximately monthly over two growing seasons from a subsample of the research plots. To determine the portion of soil surface CO₂ efflux attributable to wood-derived C, we used Keeling plot techniques to estimate the associated Î´¹³C values of the soil CO₂ efflux. We measured the Î´¹³CO₂ once during the peak of each growing season. Initial values for soil Î´¹³C values and CN concentrations averaged across the six sites were -26.8â° (standard error = 0.04), 2.46% (se = 0.11), and 0.15% (se = 0.01), respectively. The labeled wood chips from the Aspen FACE treatments had an average Î´13C value of -39.5â° (se 0.10). The >12 â° isotopic difference between the soil and wood chip Î´¹³C values provides the basis for tracking the wood-derived C through the early stages of decomposition and subsequent storage in the soil. Across our six research sites, average soil surface CO₂ efflux ranged from 1.04 to 2.00 g CO₂ m^-2 h^-1 for the first two growing seasons. No wood chip controls had an average soil surface CO₂ efflux of 0.67 g CO₂ m^-2 h^-1 or about half of that of the wood chip treatment plots. Wood-derived CO₂ efflux was higher for loam textured soils relative to sands (0.70 and 0.54 g CO₂ m^-2 h^-1, respectively; p = 0.045)), for surface relative to buried wood chip treatments (0.92 and 0.39 g CO₂ m^-2 h^-1, respectively; p < 0.001), for warmed relative to ambient temperature treatments (0.99 and 0.78 g CO₂ m^-2 h^-1, respectively; 0.004), and for natural rot relative to brown and white rots (0.93, 0.82, and 0.78 g CO₂ m^-2 h^-1, respectively; p = 0.068). Our first two growing seasons of soil surface CO₂ efflux data show that wood chip location (i.e., surface vs. buried chip application) is very important, with surface chips loosing twice the wood-derived CO₂. The DOC data support this trend for greater loss of ecosystem C from surface chips. This has strong implications for the importance of root and buried wood for ecosystem C retention. This strong chip location effect on wood-derived C loss was significantly modified by soil texture, soil temperature, decomposer communities, and wood quality as effected by potential future CO₂ and O₃ levels.
英文关键词	wood decomposition soil organic carbon stable carbon isotopes soil CO2 efflux dissolved organic carbon soil carbon stability
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来源平台	US Department of Energy (DOE)
引用统计
文献类型	科技报告
条目标识符	http://119.78.100.173/C666/handle/2XK7JSWQ/6591
专题	地球科学
推荐引用方式 GB/T 7714	Resh, Sigrid C.. Interactive Effects of Climate Change and Decomposer Communities on the Stabilization of Wood-Derived Carbon Pools: Catalyst for a New Study,2014.