scholarly journals Lignin oxidation products as a vegetation proxy in stalagmite and drip water samples from the Herbstlabyrinth, Germany

2019 ◽  
Author(s):  
Inken Heidke ◽  
Denis Scholz ◽  
Thorsten Hoffmann
Keyword(s):  
Vascular Plants ◽  
Seasonal Pattern ◽  
Water Monitoring ◽  
Oxidation Products ◽  
Trace Element Data ◽  
Central Germany ◽  
Drip Water ◽  
Lignin Oxidation ◽  
Climate Proxies ◽  
Vegetation And Climate

Abstract. Here we present the first quantitative record of lignin oxidation products (LOPs) in a Holocene stalagmite from the Herbstlabyrinth Cave in central Germany, as well as LOP results from 16 months of drip water monitoring. Lignin is only produced by vascular plants and is therefore an unambiguous vegetation proxy, which can help to better interpret other vegetation and climate proxies in speleothems. We compared our results with stable isotope and trace element data from the same samples. The drip water monitoring reveals a seasonal pattern of LOPs in a fast drip site with low LOP concentrations in winter and higher LOP concentrations in summer, which is opposite to the behaviour of the drip rate, Mg2+ and PO3−4 concentrations. In the stalagmite, LOP concentrations are correlated or show a similar behaviour to P, Ba and U concentrations. The LOP ratios C/V and S/V, which are usually used to differentiate between angiosperm and gymnosperm and woody and non-woody lignin sources, are anticorrelated to the LOP concentrations and show a similar behaviour to δ13C and Mg concentrations. These results highlight the potential of LOPs as a new, highly specific vegetation proxy in speleothems, but also demonstrate current limitations in our understanding of the transport of lignin from the soil into the cave and the speleothems.

scholarly journals Lignin oxidation products as a potential proxy for vegetation and environmental changes in speleothems and cave drip water – a first record from the Herbstlabyrinth, central Germany

2019 ◽  
Vol 15 (3) ◽  
pp. 1025-1037
Author(s):  
Inken Heidke ◽  
Denis Scholz ◽  
Thorsten Hoffmann
Keyword(s):  
Environmental Changes ◽  
Seasonal Pattern ◽  
First Record ◽  
Oxidation Products ◽  
Central Germany ◽  
Drip Water ◽  
Cave Drip Water ◽  
Lignin Oxidation ◽  
Climate Proxies ◽  
Vegetation And Climate

Abstract. Here, we present the first quantitative speleothem record of lignin oxidation products (LOPs), which has been determined in a Holocene stalagmite from the Herbstlabyrinth Cave in central Germany. In addition, we present LOP results from 16 months of drip water monitoring. Lignin is only produced by vascular plants and therefore has the potential to be an unambiguous vegetation proxy and to complement other vegetation and climate proxies in speleothems. We compare our results with stable isotope and trace element data from the same sample. In the stalagmite, LOP concentrations show a similar behavior to P, Ba and U concentrations, which have previously been interpreted as vegetation proxies. The LOP S∕V and C∕V ratios, which are usually used to differentiate between angiosperm and gymnosperm and woody and non-woody vegetation, show complex patterns suggesting additional influencing factors, such as transport and microbiological effects. The drip water from a fast drip site shows a seasonal pattern of LOPs with low LOP concentrations in winter and higher LOP concentrations in summer. These results indicate the potential of LOPs as a new proxy for vegetational and environmental changes in speleothems but also demonstrate the complexity and the current limitations of our understanding of the transport of lignin from the soil into the cave and the speleothems.

scholarly journals Quantification of lignin oxidation products as vegetation biomarkers in speleothems and cave drip water

2018 ◽  
Vol 15 (19) ◽  
pp. 5831-5845 ◽  
Author(s):  
Inken Heidke ◽  
Denis Scholz ◽  
Thorsten Hoffmann
Keyword(s):  
Organic Matter ◽  
Sample Size ◽  
Water Samples ◽  
Solid Phase ◽  
Oxidation Products ◽  
Drip Water ◽  
Cave Drip Water ◽  
Lignin Oxidation ◽  
The Individual ◽  
Sensitive Method

Abstract. Here we present a sensitive method to analyze lignin oxidation products (LOPs) in speleothems and cave drip water to provide a new tool for paleo-vegetation reconstruction. Speleothems are valuable climate archives. However, compared to other terrestrial climate archives, such as lake sediments, speleothems contain very little organic matter. Therefore, very few studies on organic biomarkers in speleothems are available. Our new sensitive method allows us to use LOPs as vegetation biomarkers in speleothems. Our method consists of acid digestion of the speleothem sample followed by solid-phase extraction (SPE) of the organic matter. The extracted polymeric lignin is degraded in a microwave-assisted alkaline CuO oxidation step to yield monomeric LOPs. The LOPs are extracted via SPE and finally analyzed via ultrahigh-performance liquid chromatography (UHPLC) coupled to electrospray ionization (ESI) and high-resolution Orbitrap mass spectrometry (HRMS). The method was applied to stalagmite samples with a sample size of 3–5 g and cave drip water samples with a sample size of 100–200 mL from the Herbstlabyrinth-Advent Cave in Germany. In addition, fresh plant samples, soil water, and powdered lignin samples were analyzed for comparison. The concentration of the sum of eight LOPs (Σ8) was in the range of 20–84 ng g−1 for the stalagmite samples and 230–440 ng L−1 for the cave drip water samples. The limits of quantification for the individual LOPs ranged from 0.3–8.2 ng per sample or 1.5–41.0 ng mL−1 of the final sample solution. Our method represents a new and powerful analytical tool for paleo-vegetation studies and has great potential to identify the pathways of lignin incorporation into speleothems.

scholarly journals Quantification of lignin oxidation products as vegetation biomarkers in speleothems and cave drip water

2018 ◽  
Author(s):  
Inken Heidke ◽  
Denis Scholz ◽  
Thorsten Hoffmann
Keyword(s):  
Organic Matter ◽  
Sample Size ◽  
Water Samples ◽  
Solid Phase ◽  
Oxidation Products ◽  
Drip Water ◽  
Cave Drip Water ◽  
Lignin Oxidation ◽  
The Individual ◽  
Sensitive Method

Abstract. Here we present a sensitive method to analyse lignin oxidation products (LOPs) in speleothems and cave drip water to provide a new tool for paleo vegetation reconstruction. Speleothems are valuable climate archives. However, compared to other terrestrial climate archives, such as lake sediments, speleothems contain very little organic matter. Therefore, very few studies on organic biomarkers in speleothems are available. Our new sensitive method allows to use LOPs as vegetation biomarkers in speleothems. Our method consists of acid digestion of the speleothem sample followed by solid phase extraction (SPE) of the organic matter. The extracted polymeric lignin is degraded in a microwave assisted alkaline CuO oxidation step to yield monomeric LOPs. The LOPs are extracted via SPE and finally analysed via ultrahigh-performance liquid chromatography (UHPLC) coupled to electrospray ionisation (ESI) and high-resolution orbitrap mass spectrometry (HRMS). The method was applied to stalagmite samples with a sample size of 3–5 g and cave drip water samples with a sample size of 100–200 mL from the Herbstlabyrinth-Advent-Cave in Germany. In addition, fresh plant samples, soil water and powdered lignin samples were analysed for comparison. The concentration of the sum of eight LOPs (Σ8) was in the range of 20–84 ng g−1 for the stalagmite samples and 230–440 ng L−1 for the cave drip water samples. The limits of quantification for the individual LOPs ranged from 0.3–8.2 ng per sample. Our method represents a new and powerful analytical tool for paleo vegetation studies and has great potential to identify the pathways of lignin incorporation into speleothems.

scholarly journals Photocatalytic Pretreatment of Commercial Lignin Using TiO2-ZnO Nanocomposite-Derived Advanced Oxidation Processes for Methane Production Synergy in Lab Scale Continuous Reactors

Catalysts ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 54
Author(s):  
Yu-Ming Chu ◽  
Hafiz Muhammad Asif Javed ◽  
Muhammad Awais ◽  
Muhammad Ijaz Khan ◽  
Sana Shafqat ◽  
...  
Keyword(s):  
Photocatalytic Oxidation ◽  
Advanced Oxidation Processes ◽  
Synergistic Effects ◽  
Oxidation Products ◽  
Methane Yield ◽  
Zno Nanoparticle ◽  
Coumaric Acid ◽  
Stirred Tank Reactors ◽  
Lignin Oxidation ◽  
Constant Operation

The photocatalytic pretreatment of lignocellulosic biomass to oxidize lignin and increase biomass stability has gained attention during the last few years. Conventional pretreatment methods are limited by the fact that they are expensive, non-renewable and contaminate the anaerobic digestate later on. The present study was focused to develop a metal-derived photocatalyst that can work with visible electromagnetic spectra light and oxidize commercial lignin liquor. During this project the advanced photocatalytic oxidation of lignin was achieved by using a quartz cube tungsten T3 Halogen 100 W lamp with a laboratory manufactured TiO2-ZnO nanoparticle (nanocomposite) in a self-designed apparatus. The products of lignin oxidation were confirmed to be vanillic acid (9.71 ± 0.23 mg/L), ferrulic acid (7.34 ± 0.16 mg/L), benzoic acid (6.12 ± 0.17 mg/L) and p-coumaric acid (3.80 ± 0.13 mg/L). These all products corresponded to 85% of the lignin oxidation products that were detectable, which is significantly more than any previously reported lignin pretreatment with even more intensity. Furthermore, all the pretreatment samples were supplemented in the form of feedstock diluent in uniformly operating continuously stirred tank reactors (CSTRs). The results of pretreatment revealed 85% lignin oxidation and later on these products did not hinder the CSTR performance at any stage. Moreover, the synergistic effects of pretreated lignin diluent were seen that resulted in 39% significant increase in the methane yield of the CSTR with constant operation. Finally, the visible light and nanoparticles alone could not pretreat lignin and when used as diluent, halted and reduced the methane yield by 37% during 4th HRT.

Integrating Stalagmite, Vertebrate, and Pollen Sequences to Investigate Holocene Vegetation and Climate Change in the Southern Midwestern United States

1999 ◽  
Vol 52 (3) ◽  
pp. 381-387 ◽  
Author(s):  
Rhawn F. Denniston ◽  
Luis A. Gonzalez ◽  
Holmes A. Semken ◽  
Yemane Asmerom ◽  
Richard G. Baker ◽  
...  
Keyword(s):  
Climate Change ◽  
Deciduous Forest ◽  
North Central ◽  
South Central ◽  
Dry Conditions ◽  
Oxygen Isotopic ◽  
Isotopic Records ◽  
Paleoclimate Records ◽  
Climate Proxies ◽  
Vegetation And Climate

Speleothem carbon and oxygen isotopic records from Onondaga Cave, south-central Missouri, and Beckham Creek Cave, north-central Arkansas, are compared with the Cupola Pond and Oldfield Swamp pollen series from southeastern Missouri and the Rodgers Shelter and Modoc Shelter vertebrate biostratigraphic sequences from central Missouri and southwestern Illinois. Similar, and roughly contemporaneous, shifts between deciduous forest and steppe indicators throughout the Holocene are revealed in each database. These independent proxies record steppe conditions between approximately 9000 and 1500 cal yr B.P. A shift toward lighter speleothem carbon may reflect a change from warm and dry to cool and dry conditions between 4500 and 3000 yr B.P. The sensitive response of speleothem δ13C to changes in vegetation emphasizes their importance as paleoclimate records in an area containing few other millenial-scale climate proxies.

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