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Studies from M. Zech and Co-Researchers Update Current Data on Chalcogens

February 11, 2014

By a News Reporter-Staff News Editor at Life Science Weekly -- Researchers detail new data in Chalcogens. According to news reporting out of Braunschweig, Germany, by NewsRx editors, research stated, "The oxygen isotopic composition of cellulose is a valuable proxy in paleoclimate research. However, its application to sedimentary archives is challenging due to extraction and purification of cellulose."

Our news journalists obtained a quote from the research, "Here we present compound-specific delta O-18 results of hemicellulose-derived sugar biomarkers determined using gas chromatography-pyrolysis-isotope ratio mass spectrometry, which is a method that overcomes the above-mentioned analytical challenges. The biomarkers were extracted from stem material of different plants (Eucalyptus globulus, Vicia faba and Brassica oleracea) grown in climate chamber experiments under different climatic conditions. The delta O-18 values of arabinose and xylose range from 31.4 parts per thousand to 45.9 parts per thousand and from 28.7 parts per thousand to 40.8 parts per thousand, respectively, and correlate highly significantly with each other (R = 0.91, p< 0.001). Furthermore, delta O-18(hemicellulose) (mean of arabinose and xylose) correlate highly significantly with delta O-18(leaf) water (R = 0.66, p< 0.001) and significantly with modeled delta O-18(cellulose) (R = 0.42, p< 0.038), as well as with relative air humidity (R = -0.79, p< 0.001) and temperature (R = -0.66, p< 0.001). These findings confirm that the hemicellulose-derived sugar biomarkers, like cellulose, reflect the oxygen isotopic composition of plant source water altered by climatically controlled evapotranspirative O-18 enrichment of leaf water. While relative air humidity controls most rigorously the evapotranspirative O-18 enrichment, the direct temperature effect is less important. However, temperature can indirectly exert influence via plant physiological reactions, namely by influencing the transpiration rate which affects delta O-18(leaf) water due to the Peclet effect. In a companion paper (Tuthorn et al., this issue) we demonstrate the applicability of the hemicellulose-derived sugar biomarker delta O-18 method to soils and provide evidence from a climate transect study confirming that relative air humidity exerts the dominant control on evapotranspirative O-18 enrichment of leaf water."

According to the news editors, the research concluded: "Finally, we present a conceptual model for the interpretation of delta(18Ohemicellulose) records and propose that a combined delta O-18(hemicellulose) and delta H-2(n-alkane) biomarker approach is promising for disentangling delta O-18(precipitation) variability from evapotranspirative O-18 enrichment variability in future paleoclimate studies."

For more information on this research see: Oxygen isotope ratios (O-18/O-16) of hemicellulose-derived sugar biomarkers in plants, soils and sediments as paleoclimate proxy I: Insight from a climate chamber experiment. Geochimica Et Cosmochimica Acta, 2014;126():614-623. Geochimica Et Cosmochimica Acta can be contacted at: Pergamon-Elsevier Science Ltd, The Boulevard, Langford Lane, Kidlington, Oxford OX5 1GB, England. (Elsevier -; Geochimica Et Cosmochimica Acta -

Our news journalists report that additional information may be obtained by contacting M. Zech, Thunen Inst Climate Smart Agr, D-38116 Braunschweig, Germany. Additional authors for this research include C. Mayr, M. Tuthorn, K. Leiber-Sauheitl and B. Glaser (see also Chalcogens).

Keywords for this news article include: Europe, Germany, Chalcogens, Braunschweig, Oxygen Isotopes

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Source: Life Science Weekly

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