scholarly journals Early diagenesis of organic matter in water of Lake Haruna. (I) Flux of organic matter to the bottom by determination of carbon and nitrogen of sediment trap sample, particulates and sediments.

1985 ◽  
Vol 46 (4) ◽  
pp. 297-302 ◽  
Author(s):  
Kazuko OGURA ◽  
Masahiro OCHIAI ◽  
Kimitaka KAWAMURA ◽  
Kazuo FUKUSHIMA ◽  
Makoto SHIOYA ◽  
...  
Keyword(s):  
Organic Matter ◽  
Sediment Trap ◽  
Early Diagenesis ◽  
Carbon And Nitrogen ◽  
Trap Sample

Studies on the Carbon and Nitrogen Cycles in the soil. II. The Extraction of the Organic Matter of the Soil With Alkali

1930 ◽  
Vol 20 (3) ◽  
pp. 460-477 ◽  
Author(s):  
C. W. B. Arnold ◽  
H. J. Page
Keyword(s):  
Organic Matter ◽  
Organic Carbon ◽  
Caustic Soda ◽  
Organic Manure ◽  
Humic Matter ◽  
Colour Intensity ◽  
Alkali Extraction ◽  
Carbon And Nitrogen ◽  
Manurial Treatment

The alkali extraction of the organic matter from the soils of certain plots of the classical permanent experiments on Barnfield and Broadbalk at Rothamsted, receiving respectively organic manure, artificial fertilisers and no manurial treatment, has been studied, together with a colorimetric examination of the extracts for the comparison of the content of humic matter.It is shown that, in spite of the different cultural and manurial treatments which the different plots have received, there is a marked similarity in the properties of the organic matter of these soils, with regard to its behaviour on extraction with cold and hot dilute caustic soda, and the colour intensity of the organic matter in the extracts.The methods used for the determination of organic carbon in the soils and their extracts are noted in an Appendix.The results discussed in this paper are further considered, along with those in the two next following Parts (III and IV), in Part V of this series, in their bearings on the origin of the humic matter of the soil.

Effect of Hydrogen Peroxide on soil Organic Matter

1931 ◽  
Vol 21 (2) ◽  
pp. 251-261 ◽  
Author(s):  
W. McLean
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Second Phase ◽  
Carbon And Nitrogen ◽  
Carbohydrate Complex ◽  
Carbon Compounds ◽  
Carbon Nitrogen Ratio ◽  
Nitrogen Ratio ◽  
Two Phases

1. Six per cent. peroxide is found to be unsuitable as a reagent for the determination of the “degree of humification” of soil organic matter, as it oxidises not only compounds containing carbon and nitrogen but also a varying amount of a substance containing carbon but no nitrogen, this amount depending on the volume of reagent used and the total amount of carbon originally present in the quantity of soil employed.2. There are apparently two phases in the attack of peroxide on soil organic matter. In the first phase, material containing carbon and nitrogen is oxidised, whilst in the second phase the material oxidised consists solely of nitrogen-free carbon compounds.3. By the use of 3 per cent. peroxide (2 per cent, or less may be preferable for some soils) the attack on soil organic matter can be restricted to the first phase. The material thus oxidised appears to be built up by the association of a protein complex with a carbohydrate complex of high carbon content. Its carbon-nitrogen ratio is about 10:1.

scholarly journals Modelling biogeochemical processes in sediments from the north-western Adriatic Sea: response to enhanced particulate organic carbon fluxes

2018 ◽  
Vol 15 (5) ◽  
pp. 1347-1366 ◽  
Author(s):  
Daniele Brigolin ◽  
Christophe Rabouille ◽  
Bruno Bombled ◽  
Silvia Colla ◽  
Salvatrice Vizzini ◽  
...  
Keyword(s):  
Organic Matter ◽  
Organic Carbon ◽  
Particulate Organic Carbon ◽  
Sediment Trap ◽  
Adriatic Sea ◽  
Early Diagenesis ◽  
Local Source ◽  
The North ◽  
North Western ◽  
Mussel Farm

Abstract. This work presents the result of a study carried out in the north-western Adriatic Sea, by combining two different types of biogeochemical models with field sampling efforts. A longline mussel farm was taken as a local source of perturbation to the natural particulate organic carbon (POC) downward flux. This flux was first quantified by means of a pelagic model of POC deposition coupled to sediment trap data, and its effects on sediment bioirrigation capacity and organic matter (OM) degradation pathways were investigated constraining an early diagenesis model by using original data collected in sediment porewater. The measurements were performed at stations located inside and outside the area affected by mussel farm deposition. Model-predicted POC fluxes showed marked spatial and temporal variability, which was mostly associated with the dynamics of the farming cycle. Sediment trap data at the two sampled stations (inside and outside of the mussel farm) showed average POC background flux of 20.0–24.2 mmol C m−2 d−1. The difference of organic carbon (OC) fluxes between the two stations was in agreement with model results, ranging between 3.3 and 14.2 mmol C m−2 d−1, and was primarily associated with mussel physiological conditions. Although restricted, these changes in POC fluxes induced visible effects on sediment biogeochemistry. Observed oxygen microprofiles presented a 50 % decrease in oxygen penetration depth (from 2.3 to 1.4 mm), accompanied by an increase in the O2 influx at the station below the mussel farm (19–31 versus 10–12 mmol O2 m−2 d−1) characterised by higher POC flux. Dissolved inorganic carbon (DIC) and NH4+ concentrations showed similar behaviour, with a more evident effect of bioirrigation underneath the farm. This was confirmed through constraining the early diagenesis model, of which calibration leads to an estimation of enhanced and shallower bioirrigation underneath the farm: bioirrigation rates of 40 yr−1 and irrigation depth of 15 cm were estimated inside the shellfish deposition footprint versus 20 yr−1 and 20 cm outside. These findings were confirmed by independent data on macrofauna composition collected at the study site. Early diagenesis model results indicated a larger organic matter mineralisation below the mussel farm (11.1 versus 18.7 mmol m−2 d−1), characterised by similar proportions between oxic and anoxic degradation rates at the two stations, with an increase in the absolute values of oxygen consumed by OM degradation and reduced substances re-oxidation underneath the mussel farm.

scholarly journals Carbon and nitrogen dynamics in decaying wood: paleoenvironmental implications

2017 ◽  
Vol 14 (1) ◽  
pp. 9 ◽  
Author(s):  
Romain Tramoy ◽  
Mathieu Sebilo ◽  
Thanh Thuy Nguyen Tu ◽  
Johann Schnyder
Keyword(s):  
Organic Matter ◽  
Mass Loss ◽  
River Water ◽  
Nitrogen Isotopes ◽  
Nitrogen Dynamics ◽  
Early Diagenesis ◽  
Distilled Water ◽  
Carbon And Nitrogen ◽  
Carbon And Nitrogen Dynamics ◽  
Paleoenvironmental Reconstructions

Environmental contextCarbon and nitrogen isotopes in terrestrial organic matter are widely used for reconstructing past environments, but organic matter is exposed to degradation as soon as it is deposited during what is called early diagenesis. This study explores the effects of this process on organic carbon and nitrogen isotopes, and concludes that it homogenises an environmental signal by integrating all their components. Thus, early diagenesis may not preclude paleoenvironmental reconstructions. AbstractThe effect of early diagenesis on carbon and, especially, nitrogen isotopes (δ13C and δ15N) of organic matter is not well understood and is of interest for accurate paleoenvironmental reconstructions. Wood samples were incubated in distilled water and river water to assess the effects of early diagenesis on carbon and nitrogen dynamics. Elemental content and isotopic composition of carbon and nitrogen as well as mass loss of wood pieces were determined. Mass loss in river water was three times greater than in distilled water. This difference was attributed to the development of two different types of fungi characterised by various degradation rates. Carbon dynamics of wood samples showed similar patterns in both type of water: (i) a sharp increase in carbon content, possibly related to carbohydrate degradation, before it slowly returned towards initial values, and (ii) no significant changes in δ13C values. In contrast, nitrogen dynamics of samples showed complex patterns: (i) N release associated with 15N depletion in distilled water, attributed to uptake of 15N-enriched pool (i.e. proteins) by fungi, and (ii) N accumulation associated with 15N enrichment in river water. The latter pattern was attributed predominantly to microbially mediated importation of 15N-enriched nitrate from river water. Although challenging, the present results suggest that early diagenesis may average an environmental signal by integrating individual signals (woods, fungi, water) and microbial processes. Considering the non-linear behaviour of early diagenesis, this integration is probably almost instantaneous on the geological time scale, which may not preclude paleoenvironmental reconstructions.

Biometrics, Carbon and Nitrogen Content in the Ophiuroid Ophiothrix Fragilis

1992 ◽  
Vol 72 (4) ◽  
pp. 915-918 ◽  
Author(s):  
D. Davoult ◽  
N. Degros ◽  
M. A. Janquín ◽  
B. Soyez
Keyword(s):  
Organic Matter ◽  
Nitrogen Content ◽  
Dry Weight ◽  
Pure Oxygen ◽  
Conversion Factors ◽  
Carbon And Nitrogen ◽  
Epifaunal Community ◽  
Wet Weight ◽  
Carbon And Nitrogen Content

Relationships between size, wet weight, dry weight, carbon and nitrogen content were determined in Ophiothrix fragilis (Echinodermata: Ophiuroidea). Such relationships appeared very useful when studying dynamic processes such as nutrition, growth, excretion or reproduction, considered as fluxes of carbon and nitrogen in the ecosystem.Relationships between size, wet weight, dry weight, ash free dry weight, carbon and nitrogen content of organisms are of fundamental interest in ecological studies of ecosystems. They allow us to understand and quantify the role of a species as it stores, consumes or produces organic matter during its life cycle. Determination of conversion factors are time-consuming but very useful for estimating flows in the ecosystem (Brey et al., 1988). Some compilations of conversion factors have been published (Båmstedt, 1981; Rumohr et al., 1987).Ophiothrix fragilis (Abildgaard) is the dominant species of the ‘pebbles with sessile epifaunal community’ (Davoult, 1990), located in the Dover Strait (eastern Channel), where tidal currents are very strong. It is considered as an efficient suspension feeder (Roushdy & Hansen, 1960; Warner, 1971) and lives in dense populations (1000–2000 individuals m-2; Davoult, 1989) which are assumed to have a significant effect on the fluxes of organic matter from the pelagic to the benthic system and on the fluxes of ammonium to the water column (Davoult et al., 1991).Individuals were sampled in May and June 1991 off the Cape Gris-Nez (50°55′N 1°35′E). Two-hundred individuals were measured (diameter ±01 mm, after Guille, 1964), dried at 60°C for 48 h, weighed (±0·1 mg), burnt at 520°C for 6 h (Anonymous, 1986), and the ash weighed (±0·1 mg). Total organic carbon and nitrogen content were determined with a CHN element analyser (Carlo Erba 1106): after a flash combustion in a helium stream temporarily enriched with pure oxygen, quantitative combustion was achieved by passing gases over Cr2O3 after a transfer through a reduction reactor to eliminate the excess of oxygen; components were separated in a chromato-graphic column, eluted, then measured by a thermal conductivity detector. Thirty-eight dried ophiuroids were ground with a micro-grinder, then two sub-samples (except for individuals <2 mm) were weighed at ±1 μg (76 measurements).

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