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Micromorphological evidence of black carbon in colluvial soils from NW Spain
Author(s) -
Kaal J.,
Van Mourik J. M.
Publication year - 2008
Publication title -
european journal of soil science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.244
H-Index - 111
eISSN - 1365-2389
pISSN - 1351-0754
DOI - 10.1111/j.1365-2389.2008.01084.x
Subject(s) - colluvium , organic matter , soil water , total organic carbon , geology , holocene , radiocarbon dating , soil organic matter , carbon fibers , environmental science , soil science , soil carbon , environmental chemistry , mineralogy , geochemistry , chemistry , paleontology , materials science , organic chemistry , composite number , composite material
Summary Biomass burning produces a residue called black carbon (BC). Black C is generally considered to be highly resistant against biodegradation and has a potential role in the global C cycle, but is difficult to identify and quantify when subjected to prolonged degradation in terrestrial sediments. The colluvial soils from Campo Lameiro (NW Spain), also known as ‘Atlantic rankers’, are rich in organic matter (up to 140 g C kg −1 soil). A micromorphological study was undertaken to test the hypothesis that a large proportion of the organic matter was derived from BC formed during Holocene wildfires (up to > 6000 years ago). As roughly estimated from image analysis of 12 thin sections, the volumetric BC contribution ranged between 10 and 60% (26% on average) of the organic matter. This is a conservative estimate as additional morphologically unrecognizable BC was present in the microgranular matrix of coalesced excrement. We conclude that (i) currently unknown quantities of BC are stored in Atlantic rankers and (ii) analysis of thin sections is an effective tool to identify BC.