The Spatial Variability of Organic Matter and Decomposition Processes at the Marsh Scale
AffiliationUniv Arizona, Sch Earth & Space Explorat
MetadataShow full item record
PublisherAMER GEOPHYSICAL UNION
CitationYousefi Lalimi, F., Silvestri, S., D'Alpaos, A., Roner, M., & Marani, M. ( 2018). The spatial variability of organic matter and decomposition processes at the Marsh scale. Journal of Geophysical Research: Biogeosciences, 123, 3713– 3727. https://doi.org/10.1029/2017JG004211
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AbstractAccretion rate in salt marshes is governed by inorganic soil deposition and soil organic matter (SOM) accumulation. Existing (limited) observations and modeling results suggest that SOM amounts, biomass production, and decomposition processes should vary widely and systematically at the marsh scale. However, we lack observations aimed at understanding how SOM production is modulated spatially within a marsh, and at elucidating the relative importance of the controlling processes. The little existing data suggest that competing effects between biomass production and decomposition processes determine an approximately spatially constant contribution of SOM to total accretion. Here we investigate this idea using concurrent observations of SOM and decomposition rates from marshes in North Carolina. Our results indicate that systematic spatial variations in SOM are small, possibly as a result of an at least partial compensation of opposing trends in biomass production and decomposed organic matter. Our analyses show that deeper soil layers are, on average, characterized by lower decomposition rates and higher stabilization factors than shallower layers, likely because of differences in the persistence of water-logged conditions. Overall, decomposition processes are sufficiently rapid that the labile material in the fresh biomass is completely decomposed before it can be sufficiently buried and stabilized. Our findings point to the importance of the fraction of initially refractory material and of stabilization processes in determining the final distribution of SOM within the soil column.
Note6 month embargo; published online: 6 December 2018
VersionFinal published version
SponsorsDuke Wetland Center Graduate Student Research Grant 2015; Duke Graduate Student Training Enhancement Grant 2016; National Science Foundation, Geomorphology and Landuse Dynamics Program [EAR-1530233]; RITMARE-SOLVE project - Italian National Commission for Research; CORILA