Comment on “Quantification of lignin oxidation products as vegetation biomarkers in speleothems and cave drip water” by Inken Heidke et al.

2018 ◽  
Author(s):  
Anonymous
Keyword(s):  
Oxidation Products ◽  
Drip Water ◽  
Cave Drip Water ◽  
Lignin Oxidation

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 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 ◽  
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 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 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.

scholarly journals Reconstruction of drip-water δ<sup>18</sup>O based on calcite oxygen and clumped isotopes of speleothems from Bunker Cave (Germany)

2013 ◽  
Vol 9 (1) ◽  
pp. 377-391 ◽  
Author(s):  
T. Kluge ◽  
H. P. Affek ◽  
T. Marx ◽  
W. Aeschbach-Hertig ◽  
D. F. C. Riechelmann ◽  
...  
Keyword(s):  
Variation Method ◽  
Clumped Isotopes ◽  
New Approach ◽  
Drip Water ◽  
The Holocene ◽  
Water Composition ◽  
Kinetic Isotope ◽  
Cave Drip Water ◽  
Clumped Isotope ◽  
Kinetic Fractionation

Abstract. The geochemical signature of many speleothems used for reconstruction of past continental climates is affected by kinetic isotope fractionation. This limits quantitative paleoclimate reconstruction and, in cases where the kinetic fractionation varies with time, also affects relative paleoclimate interpretations. In carbonate archive research, clumped isotope thermometry is typically used as proxy for absolute temperatures. In the case of speleothems, however, clumped isotopes provide a sensitive indicator for disequilibrium effects. The extent of kinetic fractionation co-varies in Δ47 and δ18O so that it can be used to account for disequilibrium in δ18O and to extract the past drip-water composition. Here we apply this approach to stalagmites from Bunker Cave (Germany) and calculate drip-water δ18Ow values for the Eemian, MIS3, and the Holocene, relying on independent temperature estimates and accounting for disequilibrium. Applying the co-variation method to modern calcite precipitates yields drip-water δ18Ow values in agreement with modern cave drip-water δ18Ow of −7.9 ± 0.3‰, despite large and variable disequilibrium effects in both calcite δ18Oc and Δ47. Reconstructed paleo-drip-water δ18Ow values are lower during colder periods (e.g., MIS3: −8.6 ± 0.4‰ and the early Holocene at 11 ka: −9.7 ± 0.2‰) and show higher values during warmer climatic periods (e.g., the Eemian: −7.6 ± 0.2‰ and the Holocene Climatic Optimum: −7.2 ± 0.3‰). This new approach offers a unique possibility for quantitative climate reconstruction including the assessment of past hydrological conditions while accounting for disequilibrium effects.

Cave drip water solutes in south-eastern Australia: Constraining sources, sinks and processes

2019 ◽  
Vol 651 ◽  
pp. 2175-2186 ◽  
Author(s):  
Carol V. Tadros ◽  
Pauline C. Treble ◽  
Andy Baker ◽  
Stuart Hankin ◽  
Regina Roach
Keyword(s):  
Drip Water ◽  
South Eastern ◽  
Cave Drip Water ◽  
Eastern Australia ◽  
South Eastern Australia

scholarly journals Cave Drip Water-Related Samples as a Natural Environment for Aromatic Hydrocarbon-Degrading Bacteria

2019 ◽  
Vol 7 (2) ◽  
pp. 33 ◽  
Author(s):  
Eric Marques ◽  
Gislaine Silva ◽  
João Dias ◽  
Eduardo Gross ◽  
Moara Costa ◽  
...  
Keyword(s):  
Aromatic Hydrocarbon ◽  
Microbial Communities ◽  
16S Rdna ◽  
Aromatic Compounds ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Amplicon Sequencing ◽  
Drip Water ◽  
Rdna Sequencing ◽  
Degrading Bacteria ◽  
Cave Drip Water

Restricted contact with the external environment has allowed the development of microbial communities adapted to the oligotrophy of caves. However, nutrients can be transported to caves by drip water and affect the microbial communities inside the cave. To evaluate the influence of aromatic compounds carried by drip water on the microbial community, two limestone caves were selected in Brazil. Drip-water-saturated and unsaturated sediment, and dripping water itself, were collected from each cave and bacterial 16S rDNA amplicon sequencing and denaturing gradient gel electrophoresis (DGGE) of naphthalene dioxygenase (ndo) genes were performed. Energy-dispersive X-ray spectroscopy (EDX) and atomic absorption spectroscopy (AAS) were performed to evaluate inorganic nutrients, and GC was performed to estimate aromatic compounds in the samples. The high frequency of Sphingomonadaceae in drip water samples indicates the presence of aromatic hydrocarbon-degrading bacteria. This finding was consistent with the detection of naphthalene and acenaphthene and the presence of ndo genes in drip-water-related samples. The aromatic compounds, aromatic hydrocarbon-degrading bacteria and 16S rDNA sequencing indicate that aromatic compounds may be one of the sources of energy and carbon to the system and the drip-water-associated bacterial community contains several potentially aromatic hydrocarbon-degrading bacteria. To the best of our knowledge, this is the first work to present compelling evidence for the presence of aromatic hydrocarbon-degrading bacteria in cave drip water.

scholarly journals The Influences of Hydrology on the Radiogenic and Stable Carbon Isotope Composition of Cave Drip Water, Grotta di Ernesto (Italy)

Radiocarbon ◽  
2010 ◽  
Vol 52 (4) ◽  
pp. 1529-1544 ◽  
Author(s):  
J Fohlmeister ◽  
A Schröder-Ritzrau ◽  
C Spötl ◽  
S Frisia ◽  
R Miorandi ◽  
...  
Keyword(s):  
Soil Carbon ◽  
Water Cycle ◽  
Isotope Composition ◽  
Stable Carbon Isotope ◽  
Carbon Dynamics ◽  
Calcite Dissolution ◽  
Drip Water ◽  
Soil Carbon Dynamics ◽  
Ne Italy ◽  
Cave Drip Water

14C and δ13C values of C-containing species in cave drip waters are mainly controlled by the C isotope composition of karst rock and soil air, as well as by soil carbon dynamics, in particular the amount of soil CO2 in the unsaturated soil zone and the process of calcite dissolution. Here, we investigate soil carbon dynamics by analyzing the 14C activity and δ13C values of C dissolved in cave drip water. Monthly over a 2-yr period, we collected drip water from 2 drip sites, one fast and one relatively slow, within the shallow Grotta di Ernesto Cave (NE Italy). The 14C data reveal a pronounced annual cycle. In contrast, the δ13C values do not show an annual pattern and only small interannual variability compared to the δ13C values of soil waters. The annual 14C drip-water cycle is a function of drip-rate variability, soil moisture, and ultimately hydrology.

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