High variability in the decay of dissolved organic carbon from different boreal litter sources; a challenge to land-water carbon flux modeling

• Dynamic ecosystem modelling offers potentially groundbreaking possibilities to reconstruct and project exports of Dissolved Organic Carbon (DOC) from land to surface water. However, the balance between production, degradation and export of soil DOC remains a challenge to model in boreal forests, partly because variability in soil DOC turnover is poorly understood. Here we determined the heterogeneity in decay potentials for DOC leached from main litter sources in boreal forest. We measured 48h leaching potentials (20°C in pure water) of fresh and pre-degraded leaf and wood litter, and subsequently performed short- and long-term standardized bioassays. Leaching and decay potentials of DOC varied more than tenfold between species. Broadleaf trees and shrubs generally showed highest magnitudes and variability in both DOC leaching and subsequent decay, compared to coniferous materials. However, it appears impossible to predict differences in decay potentials without considering both the physical structure and chemical composition of source materials. We suggest that a thorough inventory of soil DOC sources with regard to decay potentials is needed to adequately model the response in DOC export to changes in climate and vegetation.

Ämnesord

NATURVETENSKAP  -- Geovetenskap och miljövetenskap (hsv//swe)

NATURAL SCIENCES  -- Earth and Related Environmental Sciences (hsv//eng)

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