Hair ice

Hair ice grows on the surface of wet, rotten hardwood at temperatures slightly below 0°C. The attraction of winter-active insects as well as the formation of very thin fibres at the beginning of hair-ice melting is presumably attributed to inherent organics. First analysis of melted, brownish hair-ice liquid confirms a high total organic carbon content in the mg/l range. By coupling of Ultra Performance Liquid Chromatography with mass spectrometry (UPLC-MS) a chromatogram with non-resolved peaks was received. Averaged spectra different retention time show peaks spreading over a mass range 100-650 Da with favored intense, odd-numbered peaks, similar to dissolved organic matter (DOM). In the next step, the desalted/ concentrated sample was measured in an Electrospray Fourier Transform Ion Cyclotron Resonance Mass Spectrometer (ESI-FTICR-MS). The received mass list was converted to correspondent formulae, plotted in a van Krevelen diagram and classified as lignin as main ingredient by comparison with two references

Heat impact caused molecular level changes in solid and dissolved soil organic matter

The ubiquitous abundance of pyrolysed, highly aromatic organic matter, called “Black Carbon” (BC), in all environmental compartments became increasingly important in different fields of research beyond intensive investigated atmospheric aerosol due to climatic relevance.Its predominant high resistance to abiotic and biotic degradation resulted in turnover times from less than a century to several millennia. This recalcitrance led to the enrichment of BC in soils, accounting for 1–6% (European forest soils) to 60% (Chernozems) of total soil organic matter (SOM). Hence, soil BC acts an important sink in the global carbon cycle. In contrast, consequences for the nitrogen cycle up to date are rather inconsistently discussed. Soil related dissolved organic matter (DOM) is a major controlling factor in soil formation, an important pathway of organic matter transport and one of the largest active carbon reservoirs on earth, if considering oceans and other bodies of water.The aim of this study was to evaluate the effects of artificially simulated wildfire by thermal treatment on the molecular composition of water extractable soil organic matter (DOM).Soils from two outdoor lysimeters with different management history were investigated. Soil samples, non-heated and heated up to 350°C were analyzed for elemental composition (carbon, nitrogen and sulfur) and for bulk molecular composition by Pyrolysis-Field Ionization Mass Spectrometry (Py-FIMS) and synchrotron-based X-ray Absorption Near-Edge Spectroscopy (XANES) at the C- and N K-edges. DOM-samples obtained by hot water extraction, desalting and concentration by solid phase extraction were subsequently analyzed by flow injection analysis in a Fourier Transform Ion Cyclotron Resonance Mass Spectrometer (FTICR-MS), equipped with an ESI source and a 7 T supra-conducting magnet (LTQ-FT Ultra, ThermoFisher Scientific). This technique is the key technique for the analysis of complex samples due to its outstanding mass resolution (used 400.000 at m/z 400 Da) and mass accuracy (≤ 1 ppm), simultaneously providing molecular level details of thousands of compounds. The characteristics and differences of the FTICR-MS spectra with as many as ten or more peaks at each nominal mass are discussed: heated samples showed considerable higher intensities of even numbered peaks. An in-house developed, automated post processing was used for further exploitation of the data with the aim of an unambiguous assignment of as many peaks as possible. Obtained mass lists were transformed for sorting and preparation/ interpretation of graphics like Kendrick and van Krevelen plots.The heat-treated solid samples show decreasing C/N ratios and the formation cyclic and N-heterocyclic compounds in good agreement among the various methods (Py-FIMS and C- and N-XANES). Detailed insight into the hot-water extracts by FTICR-MS showed clear qualitative as well as quantitative changes in the number and the intensity of nitrogen and nitrogen + sulfur containing compounds, respectively, which generally became enriched under soil heating. This demonstrates for the first time, that not only the bulk SOM is affected in structure by heat impact but also the more mobile DOM. We assume, that heat impact volatilizes and oxidizes parts of the organic substances is as expected but another part of the substances incorporates (further) nitrogen atom(s) similar to the generation of new compounds under the conditions of plasma etching in nitrogen atmosphere. This would explain to some extent, why soils are e.g. after fire clearing of vegetation are highly fertile for a short period (better plant acceptable compounds) but become more infertile in the long run, especially under tropical conditions with frequently heavy rain that would lead to an increased leaching of compounds with higher polarity

The Redox-Network of Zea mays BOA Detoxification: A Root – Microbe Cooperation

In Zea mays, (auto)toxification by the allelochemical benzoxazolinone is first avoided by glucosylation of BOA-6-OH and subsequently by glucoside carbamate and malonylglucoside carbamate synthesis. UGT BX9 is responsible for the BOA-6-OH glucosylation step, but its function in glucoside carbamate synthesis was unclear. We assumed that BOA is not the direct substrate for glucoside carbamate synthesis and that BX9 is not directly responsible for the glucosylation step. The maize endophyte Fusarium verticillioides was isolated and incubated with BOA under suboptimal oxygen supply. Under these conditions, the fungus transformed BOA into a BOA-like compound (BC) which is either used for the fungal product oHPMA or for glucoside carbamate synthesis in maize seedlings. BC, putative precursor of the unstable (2-hydroxyphenyl)carbamic acid, accumulates in the medium under oxygen depletion, but gets highly unstable when exposed to air. Thus, the carbamate pathway is the result of a tightly regulated cooperation of the endophyte and roots cells. The switch from BOA-6-O-glucoside to glucoside carbamate production is redox-sensitive, involves Fenton reactions, oxidative cleavage BX9 to shut down BOA-6-O-glucosylation and the participation of several compartments. The glucoside carbamate detoxification pathway is thought to be generally dependent on root associated microorganisms and may reflect an association of grass roots with microorganisms essentially different from those of eudicots with BOA-6-OH-glucosylation as the major detoxification pathway. Our results are in agreement with the idea that pathogenic fungi can have a mutualistic lifestyle

THE CP+TV WOOD DATA BASE (I): CAPABILITIES & APPLICATION SCOPE

For a variety of applications, we are analyzing wood types by a standardized approach of Curie-Point pyrolysis (CP) and thermovaporization (TV), both coupled with gas chromatography-mass spectrometry in order to establish a chemical reference data base (CP+TV Wood Data Base). At the present stage, we can report the following criteria for qualitative and quantitative differentiations of individual wood types. Generally, all wood types investigated exhibit very characteristic relative intensity patterns of individual compounds which enable a distinctive chemical diagnosis and biological assignment. Bark samples can easily be related to their corresponding heart wood, which means that bark is composed of the same wood type specific, principal chemical building blocks, but with different relative concentrations [1]. Even (bio-) degraded wood and even lichen covered barks exhibit characteristic, specific wood type compounds [1]. Comparisons between CP and microscopic analyses for pine wood embedded in a peat matrix of moss (Sphagnum, Polytrichum, Brown Mosses), grasses (Carex, Eriophorum) and blueberry (Vaccinium) reveal that down to less than 1% of wood can be verified [2], [3].Coniferous wood: predominant compounds are fufural, guaiacol, ethylguaiacol, vinylguaiacol, isoeugenol, vanillin and benzenediol. These compounds are present in all conifereous woods with exception of fir (no fufural) and Kauri (no guaiacol). High concentrations of 1,4-benzenediol occur in pine, juniper, redwood, fir, spruce and yellowwood, of guaiacol in fir, of fufural and of vinylphenol in Kauri and of propiovanillone in one Rimu wood.Broadleaf wood: the most prominent compound is (hydroxymethyl)phenoxy propane-2-one. Vinylguaiacol is strongly reduced in comparison to coniferous wood. Other compounds like syringol, 4-methylsyringol, syringaldehyde and 4-methylguaiacol are very prominent, too. Based on the distinct differentiation potential of the CP+TV Wood Data base, we see a wide application range. Beside others, these are the fields of archaeology (e.g. artefacts, shipbuilding, restauration), ecology (e.g. environmental estimations by paleophytocoenosis reconstruction [3], paleobotany (e.g. genetic relationship of recent to fossil wood [1]), biology (e.g. recognition of tree diseases) and the differentiation of plantation wood and wood from primeval forest for various commercial users.References[1] Mann, U., Disko, U., Hartkopf-Fröder, C., Hofmann, D., Lücke, A., Vos, H. (2016). The CP+TV Wood Data Base (II): selected case histories. International Symposium on Analytical and Applied Pyrolysis, 09.-12. May, 2016, Nancy, France, this meeting.[2] Mann, U., Disko, U., Hartkopf-Fröder, C., Hofmann, D., Lücke, A., Szymczyk, A., Vos, H. (2015) Qualitative and quantitative potential of the CP+TV Wood Data Base. 27th International Meeting on Organic Geochemistry, September 13-18, 2015, Prague, Czech Republic.[3] Mann, U., Disko, U., Giet, R., Hofmann, D. Lücke, A., Miessen, R., Vos, H. (2015) Sphagnum moss versus Betula wood: environmental estimations during the Iron and Bronze Ages (300-2900BC) by the CP+TV Wood Data Base (highmoor of the Hautes Fagnes Nature Reserve, Belgium)

Chemotaxonomy of fossil woods from the Lower Rhine Embayment, Germany

In the Lower Rhine Embayment (western Germany), the Neogene lignite bearing sequence is rich in large fossil wood trunks. Woods collected from sand-filled channels of a meandering river system (Pliocene: Reuver series) and from coal seams (Miocene: seams Garzweiler, Frimmersdorf and Morken) were investigated by Curie-point pyrolysis coupled with gas chromatography–mass spectrometry in order to determine their palaeobotanical classification. In comparison with reference data of individual pyrograms of modern woods, it became possible to classify 15 fossil wood trunks chemotaxonomically as follows: eleven samples were identified as Taxodioxylon sp. by reference Sequoia sempervirens, three samples were identified as Populoxylon sp. by reference Populus nigra and one sample was identified as Sciadopityoxylon sp. by two references of Sciadopitys verticillata. Microanatomical crosschecks describe the equivalent samples taxonomically as Taxodioxylon gypsaceum (GÖPPERT) KRÄUSEL, Taxodioxylon germanicum (GREGUSS) VAN DER BURGH, Populus nigra L. and Sciadopityoxylon wettsteinii JURASKY, and confirm the chemical classifications. For both fossil and reference woods, our relative quantifications of guaicyl and syringyl moieties are in precise accordance with discriminations of gymnosperms versus angiosperms. This means that not only unknown recent woods can chemotaxonomically accurately be determined by Curie-point pyrolysis gas chromatography–mass spectrometry and their equivalent modern wood reference from our data base, but also the taxonomy of botanically related wood types reaching back to the geological past up to a Miocene age at least