title: Towards a global assessment of pyrogenic carbon from vegetation fires.
abstract: The production of pyrogenic carbon (PyC; a continuum of organic carbon (C) ranging from partially charred biomass and charcoal to soot) is a widely acknowledged C sink, with the latest estimates indicating that ~50% of the PyC produced by vegetation fires potentially sequesters C over centuries. Nevertheless, the quantitative importance of PyC in the global C balance remains contentious, and therefore, PyC is rarely considered in global C cycle and climate studies. Here we examine the robustness of existing evidence and identify the main research gaps in the production, fluxes and fate of PyC from vegetation fires. Much of the previous work on PyC production has focused on selected components of total PyC generated in vegetation fires, likely leading to underestimates. We suggest that global PyC production could be in the range of 116-385 Tg C yr(-1) , that is ~0.2-0.6% of the annual terrestrial net primary production. According to our estimations, atmospheric emissions of soot/black C might be a smaller fraction of total PyC (<2%) than previously reported. Research on the fate of PyC in the environment has mainly focused on its degradation pathways, and its accumulation and resilience either in situ (surface soils) or in ultimate sinks (marine sediments). Off-site transport, transformation and PyC storage in intermediate pools are often overlooked, which could explain the fate of a substantial fraction of the PyC mobilized annually. We propose new research directions addressing gaps in the global PyC cycle to fully understand the importance of the products of burning in global C cycle dynamics.
authors.affiliation: Department of Geography, College of Science, Swansea University, Singleton Park, Swansea, SA2 8PP, UK.
authors.forename: Cristina
authors.initials: C
authors.lastname: Santín
authors.affiliation: Department of Geography, College of Science, Swansea University, Singleton Park, Swansea, SA2 8PP, UK.
authors.forename: Stefan H
authors.initials: SH
authors.lastname: Doerr
authors.affiliation: School of Forest Resources and Environmental Science, Michigan Technological University, 1400 Townsend Drive, Houghton, MI, 49931, USA.
authors.forename: Evan S
authors.initials: ES
authors.lastname: Kane
authors.affiliation: Departments of Earth Science, BioSciences, and Chemistry, MS 126, Rice University, 6100 Main St, Houghton, TX 77005, USA.
authors.forename: Caroline A
authors.initials: CA
authors.lastname: Masiello
authors.affiliation: Departments of Ecology and Natural Resource Management, Norwegian University of Life Sciences, PO Box 5003, NO-1432 Ås, Norway.
authors.forename: Mikael
authors.initials: M
authors.lastname: Ohlson
authors.affiliation: Institute of Natural Resources and Agrobiology of Seville (IRNAS), CSIC, Reina Mercedes Av. 10, 41012, Seville, Spain.
authors.forename: Jose Maria
authors.initials: JM
authors.lastname: de la Rosa
authors.affiliation: Pacific Forestry Centre of Natural Resources Canada, 506 W. Burnside Rd., Victoria, BC V8Z 1M5, Canada.
authors.forename: Caroline M
authors.initials: CM
authors.lastname: Preston
authors.affiliation: Institute for Chemistry and Biology of the Marine Environment (ICBM), University of Oldenburg, Carl-von-Ossietzky-Str. 9-11, 26129, Oldenburg, Germany.
authors.forename: Thorsten
authors.initials: T
authors.lastname: Dittmar
mesh_terms: D018533:Biomass; D002244:Carbon / Q000737:chemistry*; D057486:Carbon Cycle; D002980:Climate; D005390:Fires; D010944:Plants / Q000737:chemistry; D012987:Soil / Q000737:chemistry; D053260:Soot
chemical_list: D012987:Soil; D053260:Soot; D002244:Carbon
keywords: biochar; black carbon; carbon accounting; carbon emissions; carbon sequestration; charcoal; dissolved organic carbon; erosion; pyrogenic organic matter; wildfire