Quantitative mapping and spectroscopic characterization of particulate organic matter fractions in soil profiles with imaging VisNIR spectroscopy

AbstractOrganic matter is an important constituent of soils that controls many soil functions and is of vital importance for ecosystem services like climate regulation and food security. Soil organic matter (SOM consists of a wide spectrum of different organic substances that are highly heterogeneous in terms of chemical composition, stability against microbial decomposition and turnover time. SOM is heterogeneously distributed in the soil profile impeding its fast assessment. A technique to accurately measure SOM quality and quantity with a high spatial resolution in the soil profile is presently lacking. Imaging visible light and near infrared spectroscopy (imVisIR) is a promising technique for the fast and spatially resolved assessment of SOM quality and quantity. In this study, we evaluate the potential of imVisIR to quantitatively map the labile particulate organic matter fraction in undisturbed cores from mineral soils.

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Dynamic exchange and remobilization processes as controls of soil organic carbon turnover

10.5194/egusphere-egu2020-19907 ◽

2020 ◽

Author(s):

Georg Guggenberger ◽

Patrick Liebmann ◽

Patrick Wordell-Dietrich ◽

Sebastian Preußer ◽

Fabian Kalks ◽

...

Keyword(s):

Organic Matter ◽

Organic Carbon ◽

Soil Profile ◽

Preferential Flow ◽

Mineral Soil ◽

Cascade Model ◽

Flow Paths ◽

Long Time ◽

Microbial Turnover ◽

Mineral Soils

Dissolved organic matter (DOM) can be a major source of organic carbon (OC) stocks in mineral soils of high-leaching forest ecosystems due to its high affinity towards reactive mineral phases, thus forming mineral-associated organic matter (MAOM). However, there is considerable dispute on the quantitative role of litter-derived DOM in the formation of MAOM in deeper mineral soils. There is also lacking proof, whether DOM is transported through soil via repeated sequences of sorption, microbial processing, and remobilization as is conceptualized by the `cascade model&#8217; of Kaiser and Kalbitz (DOI: 10.1016/j.soilbio.2012.04.002).We investigated into these processes by a combination of monitoring dissolved organic carbon (DOC) and CO2 fluxes in a 13C field labelling experiment at subsoil observatories, field manipulation experiments, and laboratory studies to disentangle the effects of different sources and microbial turnover on the cycling of organic matter (OM) from the top mineral soil to the subsoil.From 13C monitoring of DOM, CO2 and OM it appeared that particularly litter-derived OM leached into the soil is quickly decomposed and contributes only little to subsoil OM at a time scale of 2-3 years. The pattern of the 13C pulse in DOM and OM through the soil profile indicated a cascade-type transport of the litter-derived OM and that the MAOM formed is quite labile. The use of segmented suction plates showed that there are preferential flow paths to the subsoil that persist for years. Large DOC fluxes along these flow paths likely create hotspots where microbial processing may dominate the formation of MAOM, opposed to regions of low OM fluxes, where rather direct sorption prevails. The cascade model was also clearly supported by experiments investigating OM exchange processes of artificial mineral-organic associations exposed to field conditions. The highly OM-loaded minerals were microbial hotspots and, besides the selective retention of more strongly adsorbable DOM molecules, microbial assimilation appeared to be largely involved in the release of OM back into solution.In conclusion, repeated sorption, microbial processing and remobilization cycles appear to control the formation of MAOM during migration of OM at long time scales. While these processes partly explain concentration, age, and composition of OM within the soil profile, horizontal variability in DOM fluxes are likely the key for different processes in the formation of MAOM.

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Relationships Between Metabolic Parameters and Stream Order in Oregon

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f80-112 ◽

1980 ◽

Vol 37 (5) ◽

pp. 834-847 ◽

Cited By ~ 75

Author(s):

Robert J. Naiman ◽

James R. Sedell

Keyword(s):

Organic Matter ◽

Particulate Organic Matter ◽

Standing Stock ◽

Turnover Time ◽

Metabolic Parameters ◽

Unit Weight ◽

Community Respiration ◽

Metabolic Parameter ◽

Stream Metabolism ◽

Aquatic Moss

The light regime, standing stock of chlorophyll, and five metabolic parameters were measured seasonally at four Oregon stream sites; Devils Club Creek (1st order), Mack Creek (3rd order), Lookout Creek (5th order), and the McKenzie River (7th order). Periphyton from pools and riffles, aquatic moss (Fontinalis), fine particulate organic matter (FPOM: 0.5 μm–1 cm), and coarse particulate organic matter (CPOM: > 1 cm) were examined separately for gross production (GP), net community production (NCP), diel respiration (R24), net daily metabolism (NDM), and the production to respiration (P:R) ratio. Total autotrophic production was found to increase in a downstream direction where more light is available; however, the efficiency of light utilization is greatest in heavily shaded Mack Creek. Detrital metabolism, per unit weight, is similar in all streams for each metabolic parameter. The standing stock of detritus though, is highest in headwater streams, decreasing as streams become larger. Therefore, the relative contribution of the detritus community to total metabolism decreases downstream. Mosses occur in significant quantities only in the McKenzie River and have an areal community respiration rate about twice that of periphyton; other metabolic parameters are nearly equal in this case. On an areal basis periphyton metabolism is much greater than detrital metabolism and, as a consequence, total stream metabolism and the P:R ratio increase downstream.Gross production rates measured for these sites are some of the lowest recorded (0.1–1.0 g O2∙m−2∙d−1). These rates are compared to those from other streams in the northwestern United States and western Canada, and the importance of photosynthesis to stream systems is demonstrated. The decomposition rate of the detrital standing stock is estimated to be 0.0029–0.0057%∙m−2∙d−1 and the turnover time is calculated to be 48–93 yr for particles < 10 cm in diameter.Key words: streams, rivers, metabolism, primary production, detritus, photosynthesis, chlorophyll, respiration, light, Oregon

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Relating particulate organic matter-nitrogen (POM-N) and non-POM-N with pulse crop residues, residue management and cereal N uptake

Agronomie ◽

10.1051/agro:2002056 ◽

2002 ◽

Vol 22 (7-8) ◽

pp. 777-787 ◽

Cited By ~ 8

Author(s):

Graeme D. Schwenke ◽

Warwick L. Felton ◽

David F. Herridge ◽

Dil F. Khan ◽

Mark B. Peoples

Keyword(s):

Organic Matter ◽

Particulate Organic Matter ◽

Crop Residues ◽

N Uptake ◽

Residue Management ◽

Pulse Crop

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Macrophyte-derived detritus in shallow coastal waters contributes to suspended particulate organic matter and increases growth rates of Mytilus edulis

Marine Ecology Progress Series ◽

10.3354/meps13314 ◽

2020 ◽

Vol 644 ◽

pp. 91-103

Author(s):

D Bearham ◽

MA Vanderklift ◽

RA Downie ◽

DP Thomson ◽

LA Clementson

Keyword(s):

Organic Matter ◽

Mytilus Edulis ◽

Particulate Organic Matter ◽

Coastal Waters ◽

Gill Tissue ◽

Suspension Feeder ◽

Food Sources ◽

Suspension Feeders ◽

Blue Mussels ◽

Suspended Particulate

Benthic suspension feeders, such as bivalves, potentially have several different food sources, including plankton and resuspended detritus of benthic origin. We hypothesised that suspension feeders are likely to feed on detritus if it is present. This inference would be further strengthened if there was a correlation between δ13C of suspension feeder tissue and δ13C of particulate organic matter (POM). Since detritus is characterised by high particulate organic matter (POC):chl a ratios, we would also predict a positive correlation between POM δ13C and POC:chl a. We hypothesised that increasing depth and greater distance from shore would produce a greater nutritional reliance by experimentally transplanted blue mussels Mytilus edulis on plankton rather than macrophyte-derived detritus. After deployments of 3 mo duration in 2 different years at depths from 3 to 40 m, M. edulis sizes were positively correlated with POM concentrations. POC:chl a ratios and δ13C of POM and M. edulis gill tissue decreased with increasing depth (and greater distance from shore). δ13C of POM was correlated with δ13C of M. edulis. Our results suggest that detritus comprised a large proportion of POM at shallow depths (<15 m), that M. edulis ingested and assimilated carbon in proportion to its availability in POM, and that growth of M. edulis was higher where detritus was present and POM concentrations were higher.

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Staining particulate organic matter with DTAF--a fluorescence dye for carbohydrates and protein:a new approach and application of a 2D image analysis system

Marine Ecology Progress Series ◽

10.3354/meps171077 ◽

1998 ◽

Vol 171 ◽

pp. 77-88

Author(s):

R Schumann ◽

D Rentsch

Keyword(s):

Image Analysis ◽

Organic Matter ◽

Particulate Organic Matter ◽

Image Analysis System ◽

New Approach ◽

Fluorescence Dye ◽

Analysis System

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Characteristics of fouling due to clay-organic substances in potable water treatment by ultrafiltration

Water Science & Technology ◽

10.2166/wst.1996.0201 ◽

1996 ◽

Vol 34 (9) ◽

pp. 157-164 ◽

Cited By ~ 2

Author(s):

Kim C.-H. ◽

M. Hosomi ◽

A. Murakami ◽

M. Okada

Keyword(s):

Molecular Weight ◽

Organic Matter ◽

Humic Acid ◽

Fulvic Acid ◽

Size Distribution ◽

Ultrafiltration Membrane ◽

Organic Substances ◽

Decomposition Products ◽

Microbial Decomposition ◽

Fouling Materials

Effects of clay on fouling due to organic substances and clay were evaluated by model fouling materials and kaolin. Model fouling materials selected were protein, polysaccharide, fulvic acid, humic acid and algogenic matter (EOM:ectracellular organic matter, microbial decomposition products) and kaolin was selected as the clay material. Polysulfone membrane (MWCO(Molecular Weight Cut-Off) 10,000, 50,000 and 200,000) was used as an ultrafiltration membrane. In particular, the flux measurement of solutions containing algogenic matter used an ultrafiltration membrane of MWCO 50,000. The flux of protein and polysaccharide with coexistence of kaolin increased in the case of the ratio of MW/MWCO being greater than one, but did not increase in the case of the MW/MWCO ratio being below one. In contrast, the flux of fulvic acid and humic acid with coextence of kaolin decreased regardless of the ratio of MW/MWCO. The addition of dispersion agent and coagulant in the organic substances and kaolin mixture solution changed the size distribution of kaolin, and resulted in a change of the flux. EOM and microbial decomposition products decreased with the increase of the fraction of organic matter having molecular weight more than MWCO of membrane. The flux of the algogenic organic matter with coexistence of kaolin decreased with the increase of the amount of kaolin. It was suggested that the decline of the flux with coexistence of kaolin was due to the change of the resistance of the kaolin cake layer corresponding to the change in kaolin size distribution with charge.

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Hydrolysis of organic wastewater particles in laboratory scale and pilot scale biofilm reactors under anoxic and aerobic conditions

Water Science & Technology ◽

10.2166/wst.1998.0805 ◽

1998 ◽

Vol 38 (8-9) ◽

pp. 179-188 ◽

Cited By ~ 4

Author(s):

K. F. Janning ◽

X. Le Tallec ◽

P. Harremoës

Keyword(s):

Organic Matter ◽

Mass Balance ◽

Particulate Organic Matter ◽

Removal Rate ◽

Pilot Scale ◽

Laboratory Scale ◽

Synthetic Wastewater ◽

Aerobic Conditions ◽

Biofilm Reactors ◽

Hydrolysis Of

Hydrolysis and degradation of particulate organic matter has been isolated and investigated in laboratory scale and pilot scale biofilters. Wastewater was supplied to biofilm reactors in order to accumulate particulates from wastewater in the filter. When synthetic wastewater with no organic matter was supplied to the reactors, hydrolysis of the particulates was the only process occurring. Results from the laboratory scale experiments under aerobic conditions with pre-settled wastewater show that the initial removal rate is high: rV, O2 = 2.1 kg O2/(m3 d) though fast declining towards a much slower rate. A mass balance of carbon (TOC/TIC) shows that only 10% of the accumulated TOC was transformed to TIC during the 12 hour long experiment. The pilot scale hydrolysis experiment was performed in a new type of biofilm reactor - the B2A® biofilter that is characterised by a series of decreasing sized granular media (80-2.5 mm). When hydrolysis experiments were performed on the anoxic pilot biofilter with pre-screened wastewater particulates as carbon source, a rapid (rV, NO3=0.7 kg NO3-N/(m3 d)) and a slowler (rV, NO3 = 0.3 kg NO3-N/(m3 d)) removal rate were observed at an oxygen concentration of 3.5 mg O2/l. It was found that the pilot biofilter could retain significant amounts of particulate organic matter, reducing the porosity of the filter media of an average from 0.35 to 0.11. A mass balance of carbon shows that up to 40% of the total incoming TOC accumulates in the filter at high flow rates. Only up to 15% of the accumulated TOC was transformed to TIC during the 24 hour long experiment.

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