Labile Organic Matter in Soil Solution: II. Separation and Identification of Metabolites from Plant-Microbial Communication in Soil Solutions of Wheat Rhizospheres

2015 ◽  
pp. 173-193 ◽  
Author(s):  
Carlos M. Monreal ◽  
Morris I. Schnitzer
Keyword(s):  
Organic Matter ◽  
Soil Solution ◽  
Labile Organic Matter ◽  
Soil Solutions ◽  
Microbial Communication

scholarly journals New molecular evidence for surface and sub-surface soil erosion controls on the composition of stream DOM during storm events

2017 ◽  
Author(s):  
Marie Denis ◽  
Laurent Jeanneau ◽  
Patrice Petitjean ◽  
Anaëlle Murzeau ◽  
Marine Liotaud ◽  
...  
Keyword(s):  
Organic Matter ◽  
Soil Erosion ◽  
Soil Solution ◽  
Surface Runoff ◽  
Surface Soil ◽  
Molecular Evidence ◽  
Storm Events ◽  
Soil Solutions ◽  
Chemical Segregation ◽  
Dom Composition

Abstract. Storm events are responsible for more than 60 % of the export of dissolved organic matter (DOM) from headwater catchments due to an increase in both the discharge and concentration. The latter was attributed to changing water pathways inducing the mobilization of DOM from the surface soil horizons. Recent molecular investigations have challenged this view and hypothesized (i) a contribution of an in-stream partition of organic matter (OM) between eroded particles and the dissolved fraction and (ii) the modification of the composition of soil DOM during storm events. To investigate these assumptions, soil solutions in the macropores, surface runoff and stream outlet were sampled at high frequency during three storm events in the Kervidy-Naizin catchment, part of the French critical zone observatory AgrHys. The molecular composition of the DOM was analysed by thermally assisted hydrolysis and methylation (THM) with tetramethylammonium hydroxide (TMAH) coupled to a gas chromatograph and a quadrupole mass spectrometer. These analyses highlighted a modification of the DOM composition in soil solution controlled by the water-table dynamic and pre-event hydrological conditions. These findings fits with the mechanism of colloidal and particulate destabilization in the soil macroporosity. The different behaviour observed for lignins, carbohydrates and fatty acids highlights a potential chemical segregation based on their hydrophobicity. The composition of surface runoff DOM is similar to the DOM composition in soil solution and could be generated by the same mechanism. The DOM composition in both soil solution and surface runoff corresponds to the stream DOM composition observed during storm events. On the basis of these results, modifications of the stream DOM composition during storm events seem to be due to surface and sub-surface soil erosion rather than in-stream production.

scholarly journals New molecular evidence for surface and sub-surface soil erosion controls on the composition of stream DOM during storm events

2017 ◽  
Vol 14 (22) ◽  
pp. 5039-5051 ◽  
Author(s):  
Marie Denis ◽  
Laurent Jeanneau ◽  
Patrice Petitjean ◽  
Anaëlle Murzeau ◽  
Marine Liotaud ◽  
...  
Keyword(s):  
Organic Matter ◽  
Soil Erosion ◽  
Soil Solution ◽  
Surface Runoff ◽  
Surface Soil ◽  
Molecular Evidence ◽  
Storm Events ◽  
Soil Solutions ◽  
Chemical Segregation ◽  
Dom Composition

Abstract. Storm events are responsible for more than 60 % of the export of dissolved organic matter (DOM) from headwater catchments due to an increase in both the discharge and concentration. The latter was attributed to changing water pathways inducing the mobilization of DOM from the surface soil horizons. Recent molecular investigations have challenged this view and hypothesized (i) a contribution of an in-stream partition of organic matter (OM) between eroded particles and the dissolved fraction and (ii) the modification of the composition of soil DOM during storm events. To investigate these assumptions, soil solutions in the macropores, surface runoff and stream outlet were sampled at high frequency during three storm events in the Kervidy–Naizin catchment, part of the French critical zone observatory AgrHyS. The molecular composition of the DOM was analysed by thermally assisted hydrolysis and methylation (THM) with tetramethylammonium hydroxide (TMAH) coupled to a gas chromatograph and a quadrupole mass spectrometer. These analyses highlighted a modification of the DOM composition in soil solution controlled by the water-table dynamic and pre-event hydrological conditions. These findings fit with the mechanism of colloidal and particulate destabilization in the soil macroporosity. The different behaviour observed for lignins, carbohydrates and fatty acids highlights a potential chemical segregation based on their hydrophobicity. The composition of surface runoff DOM is similar to the DOM composition in soil solution and could be generated by the same mechanism. The DOM composition in both soil solution and surface runoff corresponds to the stream DOM composition observed during storm events. On the basis of these results, modifications of the stream DOM composition during storm events seem to be due to surface and sub-surface soil erosion rather than in-stream production.

Effect of dissolved organic matter composition on metal speciation in soil solutions

2015 ◽  
Vol 398 ◽  
pp. 61-69 ◽  
Author(s):  
Zong-Ling Ren ◽  
Marie Tella ◽  
Matthieu N. Bravin ◽  
Rob N.J. Comans ◽  
Jun Dai ◽  
...  
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Metal Speciation ◽  
Organic Matter Composition ◽  
Soil Solutions

scholarly journals Lipid biomarkers in Holocene and glacial sediments from ancient Lake Ohrid (Macedonia, Albania)

2010 ◽  
Vol 7 (11) ◽  
pp. 3473-3489 ◽  
Author(s):  
J. Holtvoeth ◽  
H. Vogel ◽  
B. Wagner ◽  
G. A. Wolff
Keyword(s):  
Organic Matter ◽  
Lipid Biomarkers ◽  
Lake Ohrid ◽  
Labile Organic Matter ◽  
Glacial Sediments ◽  
Plant Matter ◽  
Lipid Biomarker ◽  
First Results ◽  
Near Shore

Abstract. Organic matter preserved in Lake Ohrid sediments originates from aquatic and terrestrial sources. Its variable composition reflects climate-controlled changes in the lake basin's hydrology and related organic matter export, i.e. changes in primary productivity, terrestrial plant matter input and soil erosion. Here, we present first results from lipid biomarker investigations of Lake Ohrid sediments from two near-shore settings: site Lz1120 near the southern shore, with low-lying lands nearby and probably influenced by river discharge, and site Co1202 which is close to the steep eastern slopes. Variable proportions of terrestrial n-alkanoic acids and n-alkanols as well as compositional changes of ω-hydroxy acids document differences in soil organic matter supply between the sites and during different climate stages (glacial, Holocene, 8.2 ka cooling event). Changes in the vegetation cover are suggested by changes in the dominant chain length of terrestrial n-alkanols. Effective microbial degradation of labile organic matter and in situ contribution of organic matter derived from the microbes themselves are both evident in the sediments. We found evidence for anoxic conditions within the photic zone by detecting epicholestanol and tetrahymanol from sulphur-oxidising phototrophic bacteria and bacterivorous ciliates and for the influence of a settled human community from the occurrence of coprostanol, a biomarker for human and animal faeces (pigs, sheep, goats), in an early Holocene sample. This study illustrates the potential of lipid biomarkers for future environmental reconstructions using one of Europe's oldest continental climate archives, Lake Ohrid.

scholarly journals Spatiotemporal variability of sedimentary organic matter supply and recycling processes in coral reefs of Tayrona National Natural Park, Colombian Caribbean

2014 ◽  
Vol 11 (11) ◽  
pp. 2977-2990 ◽  
Author(s):  
E. Bayraktarov ◽  
C. Wild
Keyword(s):  
Organic Matter ◽  
Coral Reef ◽  
Coastal Upwelling ◽  
Sediment Traps ◽  
Sedimentary Organic Matter ◽  
Spatiotemporal Variability ◽  
Water Current ◽  
Labile Organic Matter ◽  
Natural Park ◽  
River Mouths

Abstract. Sediments are fundamental for the function of oligotrophic coral reef ecosystems because they are major places for organic matter recycling. The Tayrona National Natural Park (TNNP, Colombian Caribbean) is located between the population center Santa Marta (>455 000 inhabitants) in the southwest and several river mouths in the east. Here, coral reef sediments experience pronounced changes in environmental conditions due to seasonal coastal upwelling, but knowledge of relevant spatiotemporal effects on organic matter supply to the sediments and recycling processes is not available. Therefore, sediment traps were deployed monthly over 14 months complemented by assessment of sedimentary properties (e.g., porosity, grain size, content of particulate organic matter and pigments) and sedimentary O2 demand (SOD) at water-current-exposed and sheltered sites along distance gradients (12–20 km) to Santa Marta and the eastern river mouths (17–27 km). Findings revealed that seasonal upwelling delivered strong (75–79% of annual supply) pulses of labile organic matter mainly composed of fresh phytoplankton detritus (C : N ratio 6–8) to the seafloor. Sedimentary chlorophyll a contents and SOD increased significantly with decreasing distance to the eastern rivers, but only during upwelling. This suggests sedimentary organic matter supply controlled by nutrient-enriched upwelling waters and riverine runoff rather than by the countercurrent-located city of Santa Marta. Organic matter pulses led to significantly higher SOD (more than 30%) at the water-current-sheltered sites as compared to the exposed sites, ensuing a rapid recycling of the supplied labile organic matter in the permeable silicate reef sands.

scholarly journals The impact of four decades of annual nitrogen addition on dissolved organic matter in a boreal forest soil

2013 ◽  
Vol 10 (3) ◽  
pp. 1365-1377 ◽  
Author(s):  
M. O. Rappe-George ◽  
A. I. Gärdenäs ◽  
D. B. Kleja
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Soil Solution ◽  
Mineral Soil ◽  
Solution Concentration ◽  
Oxidative Enzymes ◽  
N Saturation ◽  
N Addition ◽  
Mineral N ◽  
The Impact

Abstract. Addition of mineral nitrogen (N) can alter the concentration and quality of dissolved organic matter (DOM) in forest soils. The aim of this study was to assess the effect of long-term mineral N addition on soil solution concentration of dissolved organic carbon (DOC) and dissolved organic nitrogen (DON) in Stråsan experimental forest (Norway spruce) in central Sweden. N was added yearly at two levels of intensity and duration: the N1 treatment represented a lower intensity but a longer duration (43 yr) of N addition than the shorter N2 treatment (24 yr). N additions were terminated in the N2 treatment in 1991. The N treatments began in 1967 when the spruce stands were 9 yr old. Soil solution in the forest floor O, and soil mineral B, horizons were sampled during the growing seasons of 1995 and 2009. Tension and non-tension lysimeters were installed in the O horizon (n = 6), and tension lysimeters were installed in the underlying B horizon (n = 4): soil solution was sampled at two-week intervals. Although tree growth and O horizon carbon (C) and N stock increased in treatments N1 and N2, the concentration of DOC in O horizon leachates was similar in both N treatments and control. This suggests an inhibitory direct effect of N addition on O horizon DOC. Elevated DON and nitrate in O horizon leachates in the ongoing N1 treatment indicated a move towards N saturation. In B horizon leachates, the N1 treatment approximately doubled leachate concentrations of DOC and DON. DON returned to control levels, but DOC remained elevated in B horizon leachates in N2 plots nineteen years after termination of N addition. We propose three possible explanations for the increased DOC in mineral soil: (i) the result of decomposition of a larger amount of root litter, either directly producing DOC or (ii) indirectly via priming of old SOM, and/or (iii) a suppression of extracellular oxidative enzymes.

scholarly journals Changes of risky element concentrations under organic and mineral fertilization  

2016 ◽  
Vol 62 (No. 8) ◽  
pp. 355-360 ◽  
Author(s):  
L. Hlisnikovský ◽  
G. Mühlbachová ◽  
E. Kunzová ◽  
M. Hejcman ◽  
M. Pechová
Keyword(s):  
Organic Matter ◽  
Ph Value ◽  
Mineral Fertilizer ◽  
Organic Fertilizers ◽  
Pig Slurry ◽  
Mineral Fertilization ◽  
Labile Organic Matter ◽  
Element Concentrations ◽  
Fresh Organic Matter ◽  
The Impact

The 28-day incubation experiment was carried out to evaluate the impact of the application of digestate (Dig); digestate with straw (DigSt); pig slurry (Slu) and mineral fertilizer (NPK) on Cd, Cu, Mn and Zn availability, on K<sub>2</sub>SO<sub>4</sub>-extractable carbon content and on the soil pH value in long-term contaminated soil. At days three and seven of the experiment, the 0.01 mol/L CaCl<sub>2</sub>-extractable fractions of Cd, Zn and Mn significantly decreased under organic treatments (Dig, DigSt and Slu) with the most pronounced effect under Dig treatment. The NPK treatment caused the increase of risky element concentrations since day 21 of incubation which was accompanied with pH decrease. The contents of 0.5 mol/L K<sub>2</sub>SO<sub>4</sub>-extractable carbon were the highest at day 3 and 7 of incubation in organic treatments. The significant correlations between 0.5 mol/L K<sub>2</sub>SO<sub>4</sub>-extractable carbon and CaCl<sub>2</sub>-extractable metal concentrations showed a close relationship between fresh organic matter added in organic fertilizers and risky element availability, suggesting that newly added labile organic matter can form temporary ligands with risky elements and release them later following its decomposition.  

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