title: Black Carbon Contribution to Organic Carbon Stocks in Urban Soil.
abstract: Soil holds 75% of the total organic carbon (TOC) stock in terrestrial ecosystems. This comprises ecosystem-derived organic carbon (OC) and black carbon (BC), a recalcitrant product of the incomplete combustion of fossil fuels and biomass. Urban topsoils are often enriched in BC from historical emissions of soot and have high TOC concentrations, but the contribution of BC to TOC throughout the urban soil profile, at a regional scale is unknown. We sampled 55 urban soil profiles across the North East of England, a region with a history of coal burning and heavy industry. Through combined elemental and thermogravimetic analyses, we found very large total soil OC stocks (31-65 kg m(-2) to 1 m), exceeding typical values reported for UK woodland soils. BC contributed 28-39% of the TOC stocks, up to 23 kg C m(-2) to 1 m, and was affected by soil texture. The proportional contribution of the BC-rich fraction to TOC increased with soil depth, and was enriched in topsoil under trees when compared to grassland. Our findings establish the importance of urban ecosystems in storing large amounts of OC in soils and that these soils also capture a large proportion of BC particulates emitted within urban areas.
authors.affiliation: †Department of Animal and Plant Sciences, University of Sheffield, Sheffield S10 2TN, U.K.
authors.forename: Jill L
authors.initials: JL
authors.lastname: Edmondson
authors.affiliation: ‡Environment and Sustainability Institute, University of Exeter, Penryn, Cornwall TR10 9FE, U.K.
authors.forename: Iain
authors.initials: I
authors.lastname: Stott
authors.affiliation: †Department of Animal and Plant Sciences, University of Sheffield, Sheffield S10 2TN, U.K.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Potter
authors.affiliation: §School of Civil Engineering and Geosciences, Newcastle University, Newcastle upon Tyne NE1 7RU, U.K.
authors.forename: Elisa
authors.initials: E
authors.lastname: Lopez-Capel
authors.affiliation: §School of Civil Engineering and Geosciences, Newcastle University, Newcastle upon Tyne NE1 7RU, U.K.
authors.forename: David A C
authors.initials: DA
authors.lastname: Manning
authors.affiliation: ‡Environment and Sustainability Institute, University of Exeter, Penryn, Cornwall TR10 9FE, U.K.
authors.forename: Kevin J
authors.initials: KJ
authors.lastname: Gaston
authors.affiliation: †Department of Animal and Plant Sciences, University of Sheffield, Sheffield S10 2TN, U.K.
authors.forename: Jonathan R
authors.initials: JR
authors.lastname: Leake
mesh_terms: D002244:Carbon / Q000032:analysis*; D002947:Cities; D004739:England; D065948:Grassland; D009930:Organic Chemicals / Q000032:analysis*; D012987:Soil / Q000737:chemistry*; D012989:Soil Pollutants / Q000032:analysis; D053260:Soot / Q000032:analysis*
chemical_list: D009930:Organic Chemicals; D012987:Soil; D012989:Soil Pollutants; D053260:Soot; D002244:Carbon