Analytical Pyrolysis and Soft‐Ionization Mass Spectrometry

Leinweber, Peter; Jandl, Gerald; Eckhardt, Kai‐Uwe; Schulten, H.‐R.; Schlichting, André; Hofmann, Diana

doi:10.1002/9780470494950.ch14

Cited by 31 publications

(21 citation statements)

References 145 publications

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“…13), and the functional group substitution (blue arrows in Fig. 13), with a significantly higher intensity of the odd-numbered masses (description of such spectra in Leinweber et al, 2009). The reason for the latter phenomenon is the mass spectrometric nitrogen rule: under electrospray conditions the ionisation is by proton transfer to [M-H] − or [M+H] + ions, therefore nitrogen-free organics like CHO and CHOS compounds are odd-numbered, while organics with one (or three or five) nitrogen atom(s) are evennumbered.…”

Section: Mass Spectrometrymentioning

confidence: 99%

Evidence for biological shaping of hair ice

Hofmann¹,

Preuss²,

Mätzler³

2015

Preprint

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Abstract. An unusual ice type, called hair ice, grows on the surface of dead wood of broad-leaf trees at temperatures slightly below 0 °C. We describe this phenomenon and present physical, chemical, and biological investigations to gain insight in the properties and processes related to hair ice. Tests revealed that the biological activity of a winter-active fungus is required in the wood for enabling the growth of hair ice. We confirmed the fungus hypothesis originally suggested by Wegener (1918) by reproducing hair ice on wood samples. Treatment by heat and fungicide, respectively, suppresses the formation of hair ice. Fruiting bodies of Asco- and Basidiomycota are identified on hair-ice carrying wood. One species, Exidiopsis effusa (Ee), has been present on all investigated samples. Both hair-ice producing wood samples and those with killed fungus show essentially the same temperature variation, indicating that the heat produced by fungal metabolism is very small, that the freezing rate is not influenced by the fungus activity and that ice segregation is the common mechanism of ice growth at the wood surface. The fungus plays the role of shaping the ice hairs and to prevent them from recrystallisation. Melted hair ice indicates the presence of organic matter. Chemical analyses show a complex mixture of several thousand CHO(N,S)-compounds similar to fulvic acids in dissolved organic matter (DOM). The evaluation reveals decomposed lignin as the main constituent. Further work is needed to clarify its role in hair-ice growth and to identify the recrystallisation inhibitor.

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Section: Mass Spectrometrymentioning

confidence: 99%

Evidence for biological shaping of hair ice

Hofmann¹,

Preuss²,

Mätzler³

2015

Preprint

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“…Volatile matter was calculated as mass loss in percentage of sample weight. Interpretation of marker signals (m/z), which are assigned to relevant compound classes, was described by Leinweber et al [49,50] and also included in the Supplementary Materials. The ion intensities of the marker signals were attributed to the following compound classes: (1) CHYDR-carbohydrates;…”

Section: Pyrolysis-field Ionization Mass Spectrometrymentioning

confidence: 99%

The Composition and Stability of Clay-Associated Organic Matter along a Soil Profile

et al. 2018

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Organic carbon in subsoil generally has longer turnover times than that in surface soil, but little is known about how the stability of the specific organic compound classes changes with soil depth. The objective of this study was to analyze the composition and thermal stability of clay-associated organic matter (OM) at varying soil depths in the summit and footslope of a pasture hillslope using C X-ray absorption near edge structure (XANES) and pyrolysis-field ionization mass spectrometry (Py-FIMS). C XANES showed aromatic C was relatively enriched in the subsoil, relative to the surface soil. Py-FIMS demonstrated a relative enrichment of phenols/lignin monomers and alkylaromatics with increasing profile depth in the summit soil, and to a greater extent in the footslope soil, followed by a decreasing abundance of sterols. In surface soil, the thermostability of clay-associated OM increases in the order: carbohydrates and N compounds < phenols/lignin monomers < lignin dimers and alkylaromatics, suggesting the intrinsic chemical nature of OM as a major driver for OM persistent in surface soil. The thermal stability of clay-associated carbohydrates, N compounds, and phenols/lignin monomers increased with profile depth, likely due to stronger organic-organic/organic-mineral binding. In subsoil, the thermal stability of clay-associated carbohydrates and N compounds can be as high as that of alkylaromatic and lignin dimers, implying that persistent subsoil OM could be composed of organic compound classes, like carbohydrates, that were traditionally considered as biochemically labile compounds. In contrast, the thermally-stable compound classes, like lignin dimers and alkylaromatics, showed no changes in the thermal stability with soil depth. This study suggests that stability of the more labile OM compounds may be more strongly influenced by the change in environmental conditions, relative to the more stable forms.

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“…As Py‐FIMS analyses revealed, the grit–crust community and thus the potential input of organic C from the grit–crust consisted of 11.5% phenolic derivates followed by 9.3% alkyl aromatic compounds. These substance classes are not just relatively heat resistant but also relatively difficult to decompose and are known to accumulate, for example, in steppe‐like environments (Leinweber et al, ). We conclude that accumulation processes lead to the formation of a terrestrial protopedon with a cryptic A horizon enriched in C and N, as suspected in our third hypothesis.…”

Section: Discussionmentioning

confidence: 99%

Desert breath—How fog promotes a novel type of soil biocenosis, forming the coastal Atacama Desert’s living skin

et al. 2019

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The Atacama Desert is the driest non‐polar desert on Earth, presenting precarious conditions for biological activity. In the arid coastal belt, life is restricted to areas with fog events that cause almost daily wet–dry cycles. In such an area, we discovered a hitherto unknown and unique ground covering biocenosis dominated by lichens, fungi, and algae attached to grit‐sized (~6 mm) quartz and granitoid stones. Comparable biocenosis forming a kind of a layer on top of soil and rock surfaces in general is summarized as cryptogamic ground covers (CGC) in literature. In contrast to known CGC from arid environments to which frequent cyclic wetting events are lethal, in the Atacama Desert every fog event is answered by photosynthetic activity of the soil community and thus considered as the desert's breath. Photosynthesis of the new CGC type is activated by the lowest amount of water known for such a community worldwide thus enabling the unique biocenosis to fulfill a variety of ecosystem services. In a considerable portion of the coastal Atacama Desert, it protects the soil from sporadically occurring splash erosion and contributes to the accumulation of soil carbon and nitrogen as well as soil formation through bio‐weathering. The structure and function of the new CGC type are discussed, and we suggest the name grit–crust. We conclude that this type of CGC can be expected in all non‐polar fog deserts of the world and may resemble the cryptogam communities that shaped ancient Earth. It may thus represent a relevant player in current and ancient biogeochemical cycling.

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Analytical Pyrolysis and Soft‐Ionization Mass Spectrometry

Cited by 31 publications

References 145 publications

Evidence for biological shaping of hair ice

Evidence for biological shaping of hair ice

The Composition and Stability of Clay-Associated Organic Matter along a Soil Profile

Desert breath—How fog promotes a novel type of soil biocenosis, forming the coastal Atacama Desert’s living skin

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