Analysis of fire-derived organic matter in soil and sediment

Analysis offire-derived organic matterin soil and sedimentMichael W. I. Schmidt

Seven take-home messages- Not all char is created equal!- Besides black C there is black N!- Report (and stay with) protocols!- Calibrate with reference materials!- Potential methodological pitfallsBeyond quantificationwhat molecular markers can tell us about- degree of degradation- formation temperature

The Black Carbon ContinuumPrecursor biomass Combustion residues Combustion condensatesCharcoalSoot(Hammes et al., 2007)

Schmidt & Noack 2000. Global Biogeochemical Cycles 14, 777-794.

Especially low temperature biomass burning forms black N (O, S...),besides black C13C NMR spectra of plant chars (b, e, h, and k)generated at 350 °C under oxic conditionsKnicker et al. 2008. Org. Geochem. 39, 935-939.

Conceptual model of SOM stabilization(very) simplified and modified afterLützow et al. 2008, Journal Plant Nutr. Soil Science 171, 111-124.A C T I V E P O O Lplant residues & exudatesmicrobial / faunal biomass & residuesI N T E R M E D I A T E P O O L1 - 10 yr10 - 100 yrdecomposed residuesmicrobial / faunal biomass & residuesP A S S I V E P O O L > 100 yrcharcoalhumic polymerspseudo-macromoleculesintercalated OMOM in clay microstructuresorgano-mineral associationsPools within brokenlines indicate postulatedpools but their existenceis not verified by directmeasurementsTransport of DOM & colloids

all C-species aromatics aliphaticscarboxyl phenolics all C-speciesComplexity of soil organic carbon forms at nanometre scalesmicroassemblage from forest soil determined by NEXAFS / STXM(Lehmann et al. 2008. Nature Geoscience 1, 238 - 242).

A basic model of a complex char particle in soil with crystalline,graphene-like sheets + randomly ordered amorphous aromaticstructures and pores (Hammes & Schmidt 2008).

How? Methods to measure BCOrganic CarbonBlack Carbon Biomass RemainsChar-BC Soot-BCInorganicCarbonates1 Separation• Optical• Thermal• Chemical2 Identification / Quantificationweighing, counting, elemental analysis (CHNO),13C NMR, …

The steering committeeMichael W. I. Schmidt - University of Zurich, Dept. of Geography, Zurich, SwitzerlandJan O. Skjemstad - CSIRO Land and Water, Adelaide, AustraliaCaroline Masiello - Rice University, Houston USAWilliam P. Ball - Johns Hopkins University, Ort, USALloyd Currie - NIST, Gaithersburg, USADwight M. Smith - University of Denver, Denver USAThe Black Carbon Ring Trial TeamMichael W. I. Schmidt, Karen Hammes (University of Zurich, Dept. of Geography, Zurich, Switzerland)Örjan Gustaffson, M. Elmquist, G. Cornelissen (Stockholm University, Institute of Applied Environmental Research (ITM), Sweden)Wiliam P. Ball, M. Fukudome, T.H. Nguyen (Johns Hopkins University Dept. of Geography andEnvironmental Engineering, USA)Wulf Amelung, Sonja Brodowski (Institute for Ecology, Technical University Berlin, Germany Dept. of SoilScience and Soil Geography, University of Bayreuth, Germany)Georg Gugenberger, Klaus Kaiser, Andrei Rodionov (Institute for Soil Science and Plant Nutrition, Martin LutherUniversity Halle-Wittenberg, Germany)Lin Huang, Wendy Zhang (Stable Isotope Laboratory, Air Quality Research Branch, Meteorological Service of Canada,Environment Canada, Canada)Barry J. Huebert (Department of Oceanography, University of Hawaii, USA)Claude Largeau, Jean-Noël Rouzaud, Cornelia Rumpel (Laboratoire de Chimie Bioorganique et Organique Physique, EcoleNationale Supérieure de Chimie de Paris, France Laboratoire de Géologie, Ecole Normale- Supérieure, Paris, France)Luyi Ding (Analysis and Air Quality Division, Environmental Technology Center, Ontario, Canada)Jan O. Skjemstad, Ron J. Smernik (CSIRO Land and Water, Glen Osmond, Australia Department of Soil andWater, University of Adelaide, Glen Osmond, Australia)Jinazhong Song, Ping’an Peng (State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry,Chinese Academy of Sciences, China)Patrick Louchouarn, Stephane Houel (Dept. of Earth and Environmental Sciences, Lamont-Doherty Earth Observatory and Earth Institute,Columbia University, New York, USA)Sid Mitra, Joshua C. Dunn (Department of Geological Sciences and Environmental Studies, Binghamton University, Binghamton, New York, USA)Patrick Hatcher, William C. Hockaday (Environmental Molecular Science Institute, Ohio State University, Columbus USA)Philip M. Gschwend, Xanat Flores (Massachusetts Institute of Technology, Cambridge, USA)Francisco Gonzalez-Vila, José A. Gonzalez-Perez, José Maria de la Rosa, O. Polvillo (Dpt. Biogeoquímica y Dinámica deContaminantes, Instituto de Recursos Naturales y Agrobiología de Sevilla (IRNAS-CSIC), Spain)Christoph Hartkopf-Fröder, Axel Böhmer, Burkhard Lüer (Geologischer Dienst NRW, Gemany)

How? Methods in briefPretreatmentOxidationBC determination(except air drying)CTO 375Carbonate removalwith HCl375 °C for 18 - 24 hMass + elementalanalysisThermal/opticalCarbonate removalwith HCl2 heating steps:Heat to 550 °CCool downReflectance/transmittanceHe-Ne laser beam(632 nm)Heat to 800 °C - 900 °CChemicalTFA-extracted at 105 °C,4 hHNO 3at 170 °C, 8 hBPCA molecularmarkers, GC/MS, /FIDHCL-demineralisationNaClO 23x 4 h13C MAS NMRWet sieved < 53 umUV photo-oxidation13C MAS NMRHF-demineralisationCN, mass differenceHCl - demineralisationK 2Cr 2O 7-H 2SO 4at22.5 °C, 55 °C, 80 °C for 24h - 400 hElemental analysis

What? 12 BC-reference materials x 20 teams4 x pure compounds- soot- wood char- grass char- no-BC sample (blank): melanoidin8 x BC in environmental matrix- urban aerosol- 2 soils: clay soil, - sand soil- marine (harbour) sediment- water filtrate- 3 rocks with different aromaticity which could be false positive(shale < lignite coal < bituminous coal)1. Intra-laboratory,2. Inter-laboratory (within-method)3. Inter-methodHammes et al. 2006, 2008a b

‘Pure’ BC: Soot & char* * *(*)* spinning sidebands (technical artifact)(*) partly spinning sidebandsHammes, Smernik, Skjemstad, Schmidt 2008, Applied Geochemistry 23, 2113

BC in soil & sedimentHammes, Smernik, Skjemstad, Schmidt 2008, Applied Geochemistry 23, 2113

- Report (and stay with) protocols!- Calibrate with reference materials!Correlation plot of results from two soils showing a) broadsystematc differences and b) major discrepancies for some labscircles off the best fit line (Hammes et al. 2007)

Conceptual summary of the ring trial results (Hammes et al. 2007)A: CTO 375, B: BPCA, C: Cr 2 O 7 , D: TOT/R, E: TG DSC, F: NaClO,G: UV.

Wrap upIntra-laboratory: reproducibility mostly goodInter-laboratory: (within-method) reproducibilitycan be good, when applied to materials method developed for(but less good for other)Inter-method:- strengths of individual methods- Report (and stay with) protocols!- Calibrate with reference materials!

- Potential methodological pitfalls

Oxidation resistant organic carbon is not always pyrogenic (black C)but in soil could also be parafinic C (e.g .from plant waxes).13C NMR spectra of plant fire-unaffected soils after oxidation for 2-6 hwith K-dichromate (K 2 Cr 2 O 7 / 2M H 2 SO 4 )Knicker et al. 2008. Geoderma 142, 178-196.

www.geo.uzh.ch/phys/bc

- Application in the field

How quickly will black carbon stocks decrease after BCinputs (wildfire) have stopped for 100 years?

Was there a change in black carbon stock over time?1900100 years no fire----------------->>1997Hammes, Torn, Lapenas, Schmidt 2008Biogeosciences 5, 1339-1350.Photo: Karen Hammes

24 % black carbon stock loss over 100 yearsHammes, Torn, Lapenas, Schmidt 2008Biogeosciences 5, 1339-1350.

293 years(210-540 years)A significant amount of black carbon turns overfaster than previously thoughtTurnover model assumptions:1. BC is homogenous2. BC loss is first order decay3. BC inputs decreased with decreasing firet = -t/ln(f-b/(f-1)Hammes, Torn, Lapenas, Schmidt 2008Biogeosciences 5, 1339-1350.

Beyond quantificationwhat molecular markers can tell us about- degree of degradation- formation temperature

Beyond quantification: BPCA method providesstructural information, tooOxidation(HNO 3 65%,170°C, 8h)COOHCOOHCOOHhemimellitic acid(example for B3CA)COOHHOOCCOOHCOOHprehnitic acid(example for B4CA)COOHHOOCCOOHHOOCCOOHHOOCCOOHCOOHmellitic acid(B6CA)(Akhter et al., 1985)HOOCCOOHCOOHpentacarboxylic acid(B5CA)Benzene polycarboxylic acid (BPCA) method(Glaser et al. 1998, Brodowski et al. 2005)

Less-condensed (easily degradable) BC decreased,Highly condensed (more recalcitrant) BC survivedover 100 yearsBPCA Stock (kg C m -2 )1900 2000B3CAB4CAB5CAB6CABenzene polycarboxylic acid (BPCA) pattern of black carbon as influenced by time 1990 vs 2000.(B3CA = ∑ hemimellitic, trimellitic, trimesic acids; B4CA = ∑ pyromellitic, prehnitic, mellophanic acis; B5CA= benzene pentacarboxylic acid; B6CA = mellitic acid) Hammes et al. 2008.

Black carbon contents of chestnut chars300250OC] -1200150BPCA-C [g kg100500200 250 300 400 500 600 700 1000n=3 (analytical replicates)Temperature [°C]Schneider, Hilf, Schmidt, poster 743-3 404, Wednesday 4pm exhibit hall E

BPCA patterns of wood charsB6CA: mellitic acidB5CA: pentacarboxylic acidB4CA: pyromellitic, prehnitic, mellophanic acidB3CA: hemimellitic and trimellitic acid10080604020Relative contrib0200 250 300 400 500 600 700 800 900 1000Pyrolysis temperature [°C]

BPCA ratios - a „thermometer“ for pyrolized wood(and maybe other species?)4030B6CA/ B5CAB6CA/ (sum B3CA;B4CA;B5CA)Ratioratio x 1002010y= 0.089*1.006 xr²=0.99200 200 400 600 800 1000 1200n=3 (analytical replicates)Temperature [°C]Schneider, Hilf, Schmidt, poster 743-3 404, Wednesday 4pm exhibit hall E

Using Black carbon molecular markers toestimate the formation temperature ofnatural charsMaximilian P. Schneider, M. Hilf, M. W.I. SchmidtCome and see poster 743-3 404Wednesday 4pm exhibit hall E

With changing climate, summers will be dryer andthe number of wildfires will increase.What will wildires do to our ecosystem carbon budget?Preston & Schmidt 2006. Biogeosciences 3, 397-420

Career options in early 20091 postdoc + 1 PhD positionPlease contact meif you are interested

Seven take-home messages- Not all char is created equal!- Besides black C there is black N!- Report (and stay with) protocols!- Calibrate with reference materials!- Potential methodological pitfallsBeyond quantificationwhat molecular markers can tell us about...- degree of degradation- formation temperature

Analysis offire-derived organic matterin soil and sedimentMichael W. I. Schmidt