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Kaal J.,Institute Ciencias del Patrimonio Incipit | Wagner S.,University of Florida | Jaffe R.,Florida International University
Journal of Analytical and Applied Pyrolysis | Year: 2016

This study aimed to assess the molecular properties of dissolved organic matter (DOM) and dissolved black carbon (DBC) using analytical pyrolysis (Py-GC-MS). The sample set was comprised of ultrafiltered DOM (UDOM) from North American headwater streams associated with Long Term Ecological Research network sites. Pyrolysis products for each UDOM sample were categorized as being sourced from non-pyrogenic sources and DBC. Major non-pyrogenic components of the headwater stream UDOM were comprised of phenolic compounds derived from lignin and chitin markers from microbial biomass, and their relative contributions indicated differences in organic matter dynamics of these ecosystems. The DBC pyrolyzates included benzene, PAHs and benzonitriles, which accounted for 12.5. ±. 4.5% of total quantified peak area (TPQA), and decreased in the order Alaskan boreal forest (19%), Alaskan tundra (17%), Appalachian deciduous forest (11%), Colorado alpine tundra (9%), Puerto Rican mountainous tropical rainforest (9%) and Kansas tallgrass prairie (7%). Pyrolysis products were compared to DBC content as determined by the benzenepolycarboxylic acid (BPCA) method. Although Py-GC-MS has quantitative limitations, this technique can detect weakly condensed and other DBC structures which fall outside of the BPCA analytical window. © 2016 Elsevier B.V. Source


We present the results of the on-going effort to measure the orientation of a comprehensive number of churches in Galicia. We have measured the orientation of the apse of 25 churches so far. Although the results are still preliminary we can obtain a number of interesting conclusions. The churches in our sample present a similar trend to those of the same period recently measured in the rest of the Iberian Peninsula. There is a general tendency towards orientations slightly north of due equinoctial east. This tendency is consistent with a use of sunrise on March 25th at the time of construction to orientate the building. In this respect, the Cathedral of Santiago may be a paradigmatic case. There are exceptions to this rule and the most interesting would be that early churches do appear to be facing westwards instead of eastward. Finally, the orientation of San Xes de Francelos allows identification with the group of churches of Asturias. © 2015, Associacao Portuguesa para o Desenvolvimento Regional (APDR). All rights reserved. Source


Calvelo Pereira R.,Massey University | Camps Arbestain M.,Massey University | Kaal J.,Institute Ciencias del Patrimonio Incipit | Vazquez Sueiro M.,Massey University | And 2 more authors.
European Journal of Soil Science | Year: 2014

The stability of biochar, a form of charcoal intentionally made to be added to soil to sequester carbon (C) and improve its function, remains unclear. As it is not feasible to perform long-term (decades, centuries) laboratory experiments to assess biochar evolution after soil amendment, the study of ancient archaeological charcoals can help to identify characteristics (and possibly molecular markers) associated with the decomposition and preservation dynamics of biochar in specific pedoclimatic environments. In this study, the chemical composition of the organic carbon fractions of three charcoals from pre-European Māori gardens of New Zealand (buried >25cm depth) was thoroughly assessed. Complementary short-term incubations of charcoals in sand were used to (i) evaluate the stability of C in the short-medium term, (ii) model its mineralization processes and (iii) estimate the C turnover. Elemental analysis, thermogravimetric analysis (TG), X-ray photoelectron spectroscopy (XPS), solid-state 13C nuclear magnetic resonance (NMR) and pyrolysis gas chromatography/mass spectroscopy (Py-GC-MS) gave consistent results in describing the charring intensity and the degree of polycondensation of these charcoals. The oldest buried deposit (770±50years BP) still retained un-charred or weakly charred lignocellulosic material, indicating that such material survived decomposition processes for several centuries. The amount of organic C mineralized in 109days was <0.5% of the initial charcoal-C. No differences in MRT among samples were detected in spite of inferred differences in thermal impact. Longer-term incubations are needed to obtain better estimates of C turnover rates in charred material. © 2013 British Society of Soil Science. Source


Kaal J.,Institute Ciencias del Patrimonio Incipit | Martinez Cortizas A.,University of Santiago de Compostela | Reyes O.,University of Santiago de Compostela | Solino M.,National Institute for Agriculture and Food Research and Technology INIA
Journal of Analytical and Applied Pyrolysis | Year: 2012

Gorse species (Ulex sp.) are ubiquitous in the shrublands of NW Spain and have the potential to become key players in an integral biofuel/biochar program in NW Spain. Here we present molecular characterization (using pyrolysis-GC/MS) of a biochar "thermosequence" obtained by laboratory heating of Ulex europaeus wood in a muffle furnace between 200 and 600°C (T CHAR). Low temperature chars (T CHAR ≤ 350°C) produced significant amounts of pyrolysis products of which the precursor biopolymer could be recognized, while high-temperature chars (T CHAR ≥ 400°C) produced mainly phenols and monocyclic and polycyclic aromatic hydrocarbons, which are not specific for any biopolymer. Carbohydrate could hardly be recognized at T CHAR ≥ 350°C. The thermal rearrangement of polyphenols, mainly lignin, was reflected in more detail (1) C 3-side chain shortening and probably depolymerization (T CHAR 200-350°C), (2) demethoxylation of syringyl and probably also some guaiacyl lignin (T CHAR 300-400°C), (3) elimination of virtually all remaining methoxyl groups (T CHAR 350-400°C), through dehydroxylation and demethoxylation, (4) almost complete dehydroxylation of lignin and other biopolymers (T CHAR 400-500°C), (5) progressive condensation into polyaromatic structures (T CHAR 300-500°C) and (6) partial elimination of alkyl bridges between (poly)aromatic moieties (T CHAR 450-500°C). These results were supported by Fourier transform infrared spectroscopy (FTIR) of the same samples. We conclude that pyrolysis-GC/MS can be used as a rapid molecular screening method of gorse-derived biochar. Molecular properties elucidation is an essential part of predicting the stability and agronomical behavior of gorse-derived biochar after future implementation in soils. © 2012 Elsevier B.V. All rights reserved. Source


Kaal J.,Institute Ciencias del Patrimonio Incipit | Schellekens J.,University Of Sa&Tild | Nierop K.G.J.,University Utrecht | Muller J.,Gulf
Palaeogeography, Palaeoclimatology, Palaeoecology | Year: 2014

The Lynch's Crater (NE Australia) deposit is a key information source on Late-Quaternary palaeoenvironmental change, including human-induced deforestation since the arrival of Aboriginals, megaherbivore extinction and southern hemisphere tropical climate dynamics. This study adds to the important dataset available for the site by assessing the molecular composition of organic matter in the record using pyrolysis-GC-MS to elucidate ecological and hydrological conditions since 55. ka BP.Pyrolysates were dominated by methylene chain compounds (MCCs) and lignin products (methoxyphenols). Concomitant increases in MCCs and aquatic source indicators (biogenic opaline silica, Si:Al ratio, SEM-visible debris of sponges and diatoms and aquatic pollen taxa), which roughly coincide with abrupt climate events in GISP2 δ18O (Heinrich event H3, H1, 8.2ka and oscillations at 33-36ka BP), reflect transitions from peat (dominated by lignin from terrestrial plants) to lacustrine (MCCs from aquatic plants) conditions. The evidence points towards wet conditions causing the accumulation of layers rich in inorganic sediment during H events, favouring the hypothesis of a southward ITCZ shift, rather than an ENSO-induced northward shift, as the underlying mechanism. This contradicts previous studies using the "degree of peat humification" index (DPH). We measured DPH and the extracts and residues by PY-GC-MS, to better understand the validity of this surface moisture proxy. Paradoxically, high DPH corresponds to the relatively young (<15ka) ombrotrophic peat environment, as DPH relies on the proportion of extractable carbohydrates concentrated in this part of the core, while deeper and unarguably more evolved layers are comprised of alkali-inextricable lignin and MCCs. Therefore, DPH does not accurately reflect humidity-controlled degradation/preservation dynamics and its use for studying climate change in complex records, such as Lynch's Crater, is cautioned. Finally, the decoupling of humidity conditions from changes in regional arboreal vegetation supports the hypothesis of an anthropogenic- rather than climate-driven shift towards sclerophyllous vegetation since 45ka, but the hydroseral complexity of the system demands caution on this matter. © 2014 Elsevier B.V. Source

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