scholarly journals Combination of Numerical Dating Techniques Using 10Be in Rock Boulders and 14C of Resilient Soil Organic Matter for Reconstructing the Chronology of Glacial and Periglacial Processes in a High Alpine Catchment during the Late Pleistocene and Early Holocene

Radiocarbon ◽  
2009 ◽  
Vol 51 (2) ◽  
pp. 537-552 ◽  
Author(s):  
Filippo Favilli ◽  
Markus Egli ◽  
Dagmar Brandova ◽  
Susan Ivy-Ochs ◽  
Peter W Kubik ◽  
...  
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Late Quaternary ◽  
Chemical Characterization ◽  
Soil Formation ◽  
Parent Material ◽  
Surface Dynamics ◽  
Exposure Dating ◽  
Minimum Age ◽  
Absolute Dating

Glacier fluctuations and paleoclimatic oscillations during the Late Quaternary in Val di Rabbi (Trentino, northern Italy) were reconstructed using a combination of absolute dating techniques (14C and 10Be) and soil chemical characterization. Extraction and dating of the stable fraction of soil organic matter (SOM) gave valuable information about the minimum age of soil formation and contributed to the deciphering of geomorphic surface dynamics. The comparison of 10Be surface exposure dating (SED) of rock surfaces with the 14C ages of resilient (resistant to H2O2 oxidation) soil organic matter gave a fairly good agreement, but with some questionable aspects. It is concluded that, applied with adequate carefulness, dating of SOM with 14C might be a useful tool in reconstructing landscape history in high Alpine areas with siliceous parent material. The combination of 14C dating of SOM with SED with cosmogenic 10Be (on moraines and erratic boulders) indicated that deglaciation processes in Val di Rabbi were already ongoing by around 14,000 cal BP at an altitude of 2300 m asl and that glacier oscillations might have affected the higher part of the region until about 9000 cal BP. 10Be and 14C ages correlate well with the altitude of the sampling sites and with the established Lateglacial chronology.

scholarly journals Twenty-Five Years of Radiocarbon Dating Soils: Paradigm of Erring and Learning

Radiocarbon ◽  
1992 ◽  
Vol 34 (3) ◽  
pp. 541-549 ◽  
Author(s):  
H. W. Scharpenseel ◽  
Peter Becker-Heidmann
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Soil Formation ◽  
Clay Content ◽  
Solvent System ◽  
Total Carbon ◽  
Earthworm Casts ◽  
Initiation Point ◽  
Organic Matter Fractions ◽  
Soil Dating

Soil organic matter sequesters close to three times the carbon existing totally in the living biomass and nearly the same for the total carbon in the atmosphere. Models, such as Jenkinson's or Parton's Century model, help to define soil organic matter fractions of different functions, based on residence time/14C age. Rejuvenation of soil carbon was felt to be the principal impediment to absolute soil dating, in addition to the ambiguity of the initiation point of soil formation and soil age. Recent studies, for example, of Becker-Heidmann (1989), indicate that a soil 14C age of >1000 yr cannot have >0.1% rejuvenation in the total soil organic matter compartments/fractions to be possible and sustainable. Always problematic in earlier observations were age vs. depth increases, in 14C profile curves showing an inflection of reduced age in the deepest samples, i.e., from the rim of the organic matter containing epipedon. We attribute this phenomenon, in mollic horizons, to earthworm casts in the terminal part of the escape tube. Becker-Heidmann (1989) has shown, in thin layer soil profile dating, a highly significant correlation between the highest 14C ages and the highest clay content. Thus, optimization of soil dating is, to a lesser degree, related to the applied extracting solvent system than to soil texture fractions. Such observations allow us to mitigate error ranges inherent in dating dynamic soil systems.

Aliphatic carboxylic acids in buried Ah horizons in Alberta, Canada as paleoenvironmental indicators

1983 ◽  
Vol 20 (5) ◽  
pp. 859-866 ◽  
Author(s):  
J. F. Dormaar
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Carboxylic Acids ◽  
Soil Formation ◽  
Aliphatic Acids ◽  
Southern Alberta ◽  
Aliphatic Carboxylic Acids ◽  
Paleoenvironmental Indicators

In southern Alberta, a buried Ah horizon is frequently present beneath Mazama tephra (ca. 6600 years BP). Drainage conditions during the formation of such buried Ah horizons may determine the quality of the aliphatic carboxylic acids in the soil organic matter. The spectrum of aliphatic acids extracted from a number of buried Ah horizons indeed suggests either well drained or poorly drained conditions during soil formation regardless of the mode of deposition of materials before or after the soil-forming interval. The climate required for development of the well drained paleosols was inferred to be similar to the climate under which surficial Black Chernozemic Ah horizons were formed.

Radiocarbon Variation in Charcoal/Wood and Soil Fractions from a Loessic Setting in Central Alaska

Radiocarbon ◽  
2016 ◽  
Vol 59 (2) ◽  
pp. 449-464 ◽  
Author(s):  
Joshua D Reuther ◽  
Alexander Cherkinsky ◽  
Sam Coffman
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Residence Time ◽  
Age Differences ◽  
Soil Formation ◽  
Soil Samples ◽  
Small Particles ◽  
Vegetation Development ◽  
Lucky Strike ◽  
Soil Residue

AbstractThe Healy’s Lucky Strike site in central Alaska has an exceptional Holocene loess-paleosol sequence that has afforded us the ability to look at variation in 14C dating of soil organic matter (SOM) fractions in a high-latitude loess setting. Our work has focused on comparing the radiocarbon ages of charcoal and wood to base-soluble humic acids (HA) and base-insoluble soil residue (SR) fractions from bulk soil samples. Charcoal/wood ages were younger than HA ages reflecting the later stages of vegetation development at the surface of the soils prior to being covered by loess accumulation; the HA ages generally reflect the overall timing of soil formation and mean residence time of SOM. Soil residue ages are older than charcoal/wood and HA ages. SOM ages at this location become increasingly older than charcoal/wood ages with depth, reaching 750 to 8070 yr in difference and associated with weakly developed soils at the lowest depths. We suggest the drastic SOM age differences at this site result from the differential incorporation of small particles of coal throughout the sedimentary matrices introduced older contaminants to SR fractions.

scholarly journals Chemical characterization and infrared spectroscopy of soil organic matter from two southern brazilian soils

2003 ◽  
Vol 27 (1) ◽  
pp. 29-39 ◽  
Author(s):  
D. P. Dick ◽  
J. H. Z. Santos ◽  
E. M. Ferranti
Keyword(s):  
Organic Matter ◽  
Infrared Spectroscopy ◽  
Soil Organic Matter ◽  
Chemical Characterization ◽  
Fulvic Acids ◽  
Alkaline Treatment ◽  
Hydrophobicity Index ◽  
Elemental Analyses ◽  
Brazilian Soils

Soil organic matter from the surface horizon of two Brazilian soils (a Latosol and a Chernosol), in bulk samples (in situ SOM) and in HF-treated samples (SOM), was characterized by elemental analyses, diffuse reflectance (DRIFT) and transmission Fourier transform infrared spectroscopy (T-FTIR). Humic acids (HA), fulvic acids (FA) and humin (HU) isolated from the SOM were characterized additionally by ultraviolet-visible spectroscopy (UV-VIS). After sample oxidation and alkaline treatment, the DRIFT technique proved to be more informative for the detection of "in situ SOM" and of residual organic matter than T-FTIR. The higher hydrophobicity index (HI) and H/C ratio obtained in the Chernosol samples indicate a stronger aliphatic character of the organic matter in this soil than the Latosol. In the latter, a pronounced HI decrease was observed after the removal of humic substances (HS). The weaker aliphatic character, the higher O/C ratio, and the T-FTIR spectrum obtained for the HU fraction in the Latosol suggest the occurrence of surface coordination of carboxylate ions. The Chernosol HU fraction was also oxygenated to a relatively high extent, but presented a stronger hydrophobic character in comparison with the Latosol HU. These differences in the chemical and functional group composition suggest a higher organic matter protection in the Latosol. After the HF treatment, decreases in the FA proportion and the A350/A550 ratio were observed. A possible loss of FA and condensation of organic molecules due to the highly acid medium should not be neglected.

Geogenic CO2 affects inorganic soil properties and the composition of soil organic matter in physical fractions

Soil Research ◽  
2018 ◽  
Vol 56 (4) ◽  
pp. 396 ◽  
Author(s):  
Thilo Rennert
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Soil Properties ◽  
Mineralogical Composition ◽  
Co2 Concentration ◽  
Exchange Capacity ◽  
Parent Material ◽  
Co2 Concentrations ◽  
Particulate Soil ◽  
Diffuse Reflectance Infrared

The presence of geogenic CO2 has been recently identified as a soil-forming factor in soil on mofette sites. Topsoil samples (with a maximum CO2 concentration of 52% at 10 cm depth) were studied along a transect on a mofette site in the NW Czech Republic to further understand the processes within soil and the soil properties induced by CO2 in the soil atmosphere. Geogenic CO2 negatively affected the cation exchange capacity, the ratio of exchangeable Ca and Mg, and the total contents of Al, Mg and Mn. No effect was detected on a chemical index of weathering and the mineralogical composition of the clay fractions, which might be explained by the acidic parent material and the progress of soil development. Diffuse reflectance infrared spectroscopy indicated that the composition of particulate soil organic matter was partially affected by CO2 concentrations: the higher the CO2 concentrations, the smaller the extent of oxidative transformation and the smaller the abundance of carboxyl groups. In the clay fractions, stabilisation of transformed soil organic matter (SOM) was promoted by exchangeable Al. This study quantifies, for the first time, the correlation between geogenic CO2 and several inorganic soil properties and the composition of SOM in physical fractions.

scholarly journals Soil organic matter and labile fractions depend on specific local parameter combinations

2021 ◽  
Author(s):  
Malte Ortner ◽  
Michael Seidel ◽  
Sebastian Semella ◽  
Thomas Udelhoven ◽  
Michael Vohland ◽  
...  
Keyword(s):  
Land Use ◽  
Organic Matter ◽  
Soil Organic Matter ◽  
Soil Texture ◽  
Local Scale ◽  
Parent Material ◽  
Hot Water ◽  
Mixed Effect ◽  
Mixed Effect Models ◽  
Specific Parameter

Abstract. Soil organic matter (SOM) is an indispensable component of terrestrial ecosystems. Soil organic carbon (SOC) dynamics are influenced by a number of well-known abiotic factors such as clay content, soil pH or pedogenic oxides. These parameters interact with each other and vary in their influence on SOC depending on local conditions. To investigate the latter, the dependence of SOC accumulation on parameters and parameter combinations was statistically assessed that vary on a local scale depending on parent material, soil texture class and land use. To this end, topsoils were sampled from arable and grassland sites in southwestern Germany at four regions with different soil parent material. Principal component analysis (PCA) revealed a distinct clustering of data according to parent material and soil texture that varied largely between the local sampling regions, while land use explained PCA results only to a small extent. The obtained global and the different local clusters of the dataset were further analyzed for the relationships between SOC and mineral phase parameters in order to assess specific parameter combinations explaining SOC and its labile fractions. Analyses were focused on soil parameters that are known as possible predictors for the occurrence and stabilization of SOC (e.g. fine silt plus clay and pedogenic oxides). Regarding the global dataset, we found significant correlations between SOC and its labile fractions hot water-extractable C (HWEC) and microbial biomass C (MBC), respectively and the predictors, yet correlation coefficients were partially low. Mixed effect models were used to identify specific parameter combinations that significantly explain SOC and its labile fractions of the different clusters. Comparing measured and mixed effect models-predicted SOC values revealed acceptable to very good regression coefficients (R² = 0.41–0.91). Thereby, the predictors and predictor combinations clearly differed between models obtained for the whole data set and the different cluster groups. At a local scale site specific combinations of parameters explained the variability of organic matter notably better, while the application of global models to local clusters resulted in less sufficient performance. Independent from that, the overall explained variance generally decreased in the order SOC > HWEC > MBC, showing that labile fractions depend less on soil properties than on organic matter input and turnover in soil.

scholarly journals Black carbon contributes to organic matter in young soils in the Morteratsch proglacial area (Switzerland)

2013 ◽  
Vol 10 (3) ◽  
pp. 1265-1274 ◽  
Author(s):  
E. Eckmeier ◽  
C. Mavris ◽  
R. Krebs ◽  
B. Pichler ◽  
M. Egli
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Black Carbon ◽  
Early Stage ◽  
Soil Formation ◽  
European Alps ◽  
Fine Earth ◽  
Main Compound ◽  
Maximum Expansion ◽  
Relative Contribution

Abstract. Most glacier forefields of the European Alps are being progressively exposed since the glaciers reached their maximum expansion in the 1850s. Global warming and climate changes additionally promote the exposure of sediments in previously glaciated areas. In these proglacial areas, initial soils have started to develop so that they may offer a continuous chronosequence from 0 to 150-yr-old soils. The build-up of organic matter is an important factor of soil formation, and not only autochthonous but also distant sources might contribute to its accumulation in young soils and surfaces of glacier forefields. Only little is known about black carbon in soils that develop in glacier forefields, although charred organic matter could be an important component of organic carbon in Alpine soils. The aim of our study was to examine whether black carbon (BC) is present in the initial soils of a proglacial area, and to estimate its relative contribution to soil organic matter. We investigated soil samples from 35 sites distributed over the whole proglacial area of Morteratsch (Upper Engadine, Switzerland), covering a chronosequence from 0 to 150 yr. BC concentrations were determined in fine earth using the benzene polycarboxylic acid (BPCA) marker method. We found that charred organic matter occurred in the whole area, and that it was a main compound of soil organic matter in the youngest soils, where total Corg concentrations were very low. The absolute concentrations of BC in fine earth were generally low but increased in soils that had been exposed for more than 40 yr. Specific initial microbial communities may profit from this additional C source during the first years of soil evolution and potentially promote soil development in its early stage.

Soil organic matter composition, transformation, and microbial colonisation of Gelic Podzols in the coastal region of East Antarctica

Soil Research ◽  
2001 ◽  
Vol 39 (3) ◽  
pp. 543 ◽  
Author(s):  
Lothar Beyer ◽  
Daniel M. White ◽  
Manfred Bölter
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Organic Acids ◽  
Coastal Region ◽  
Soil Formation ◽  
Unknown Origin ◽  
Cold Climate ◽  
Future Research ◽  
Organic C ◽  
Depth Profiles

During recent soil geographical expeditions to Casey Station (Coastal Antarctica), soils with the morphological features of Gelic Podzols (WRB: Spodic Haplic Cryosols) were found to be widespread. The purpose of this paper is to provide further information on these unique soils with respect to soil organic matter (SOM), microbiology, and soil formation. Antarctic Podzols develop on solid rock, outwash sediments, and abandoned penguin rookeries. A comparison of different SOM depth profiles, however, revealed carbon (C) and nitrogen (N) of unknown origin. The SOM composition was characterised by a mean C/N ratio of 10, with a high content of carboxyl-C units, probably derived from amino acids, organic acids, and oxidised carbohydrates. Pyrolysis-GC/MS and NMR showed a notable variation between SOM in depth profiles and the horizons within each profile. Microbial colonisation was affected by the surface vegetation, content of organic C, and the influence of seabirds. Correlations between selected SOM compounds and bacteria on the vegetated soils suggested that algal and moss C influence SOM to a great extent. Most of the long-chain C moieties in the antarctic Podzols appeared to contain multiple oxygen- and N-containing functional groups, cyclic ionised and heterocyclic structures, and alkylations. Data suggest that, along with the podzolisation process, organic acids, non-humified carbohydrates, and N-containing moieties migrated from the topsoil into the spodic horizons. The results are discussed with respect to (i) soil formation and (ii) microbial colonisation in the cold climate. The Gelic Podzols hold huge amounts of C and N but their origin is poorly understood. Explaining the origin of the SOM should be a focus for future research in antarctic soil biogeochemistry.

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