The Isotopic Composition of Reduced Organic Carbon

Deines, Peter

doi:10.1016/b978-0-444-41780-0.50015-8

Cited by 686 publications

(541 citation statements)

References 166 publications

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“…2) The polysaccharides and proteins have considerably higher 14C activities than the bulk sample. These compounds can be degraded rapidly by microorganisms in the water column (Deines 1980;Laane et al 1990), so only relatively fresh material is present. The sulfuric acid extract could not be analyzed, probably because of the presence of too much sulfur oxide in the gas mixture.…”

Section: Resultsmentioning

confidence: 99%

“…Secondly, OM from one organism is nevertheless a mixture of different compounds covering a wide range of S13C values. Polysaccharides and proteins have on average higher b13C values than lipids (Deines 1980). The 813C values of amino acids from one organism can cover a range of >10%o (Macko et a1.1994) and also lipids from one organism show large differences in S13C (Schouten et al ms.).…”

Section: Introductionmentioning

confidence: 99%

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Molecular, Radioactive and Stable Carbon Isotope Characterization of Estuarine Particulate Organic Matter

Megens¹,

Plicht²,

Leeuw³

1997

Radiocarbon

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ABSTRACT. Organic matter in sediments and suspended matter is a complex mixture of constituents with different histories, sources and stabilities. To study these components in a suspended matter sample from the Ems-Dollard Estuary, we used combined molecular analysis with pyrolysis/gas chromatography/mass spectrometry and stable and radioactive carbon isotope analyses of the bulk and separated chemical fractions. Carbohydrates and proteins, ca. 50% of the total organic carbon (TOC), are much younger than the bulk sample and have a somewhat higher 613C value. Lipids and the final residue are considerably older and have lower 613C values. The final residue, ca. 17% of the total carbon, consists mainly of aliphatic macromolecules that could be derived from algae or terrestrial plants. The 613C value points to a marine origin.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Molecular, Radioactive and Stable Carbon Isotope Characterization of Estuarine Particulate Organic Matter

Megens¹,

Plicht²,

Leeuw³

1997

Radiocarbon

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“…The carbon isotope chemistry of a soil will be therefore the result of the respiration of plant roots and the microbial decomposition of soil organic matter. For C3 plants, the average δ 13 CO2 value is -27‰ (Deines, 1980;Amundson et al, 1998). Decrease in soil δ 13 CO2 values (lighter values) points to periods dominated by soil CO2 production.…”

Section: δ 13 Co2 Isotopic Signal and Co2 Sourcesmentioning

confidence: 99%

Changes in the CO2 dynamics in near-surface cavities under a future warming scenario: Factors and evidence from the field and experimental findings

Pla

Cuezva

Garcia-Anton

et al. 2016

Science of The Total Environment

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This study is based in a field monitoring of a cave-soil-atmosphere system validated with laboratory experimentation. CO2 and 222 Rn dynamics in the cavity demonstrate the dependence on the climatic parameters, mainly on the differences between outdoor and indoor temperatures. Within the cave, the annual cycles are characterized by two outstanding moments: cave gaseous recharge and ventilation when cave acts as gaseous sink or source respectively. Relationship with soil above the cave exists permanently. Soil temperature and moisture are responsible for CO2 production at different time scales.Soil CO2 in Rull site reaches values higher than 3000 ppm in April-May, which falls to nearly 1000 ppm during the summer time. Due to CO 2 diffusion, maximum values in the cave are reached in the warmest months and are in accordance to soil CO2 values. Within the cave, maximum CO2 concentration is, in average, 3470 ppm while minimum is 623 ppm. Cave temperature and relative humidity remain quite stable with mean values of 16.1 ºC and 97.9% respectively. To describe field findings, CO2 production and diffusion experiments are developed related to soil behaviour. Results show that soil CO2 production increases as soil temperature and moisture increase according to a calculated logarithmic equation until water content in soil exceeds the saturation values. In addition, CO2 diffusion in Rull soil is reduced around 60% when water content in soil increases from 0 to 30%. Soil-produced CO2 reaches Rull cave, by diffusion. We estimate 57 kg of emitted CO2 from the cave to the atmosphere in an annual cycle, considering a volume of 9915 m 3 . Finally, projections of future climate in the study site confirm a general tendency for annual-mean conditions to be warmer and drier, which will directly affect soil CO2 production. Under this situation, Rull cave will experience changes in the stored and then exchanged annual amount of CO2.

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“…Delta 13 C values for higher plant species vary from -22 to -33 ‰ in C 3 plants to -9 to -16 ‰ in C 4 plants (Deines, 1980).…”

Section: Introductionmentioning

confidence: 99%

Soil carbon and nitrogen in pasture soil reforested with eucalyptus and guachapele

Balieiro

Pereira

Alves

et al. 2008

Rev. Bras. Ciênc. Solo

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In spite of the normally low content of organic matter found in sandy soils, it is responsible for almost the totality of cation exchange capacity (CEC), water storage and availability of plant nutrients. It is therefore important to evaluate the impact of alternative forest exploitation on the improvement of soil C and N accumulation on these soils. This study compared pure and mixed plantations of Eucalyptus grandis and Pseudosamanea guachapele, a N 2 -fixing leguminous tree, in relation to their effects on soil C and N stocks. The studied Planosol area had formerly been covered by Panicum maximum pasture for at least ten years without any fertilizer addition. To estimate C and N contents, the soil was sampled (at depths of 0-2.5; 2.5-5.0; 5.0-7.5; 7.5-10.0; 10.0-20.0 and 20.0-40.0 cm), in pure and mixed five-year-old tree plantations, as well as on adjacent pasture. The natural abundance 13 C technique was used to estimate the contribution of the soil organic C originated from the trees in the 0-10 cm soil layer. Soil C and N stocks under mixed plantation were 23.83 and 1.74 Mg ha -1 , respectively. Under guachapele, eucalyptus and pasture areas C stocks were 14.20, 17.19 and 24.24 Mg ha -1 , respectively. For these same treatments, total N contents were 0.83; 0.99 and 1.71 Mg ha -1 , respectively. Up to 40 % of the soil organic C in the mixed plantation was estimated to be derived from trees, while in pure eucalyptus and guachapele plantations these same estimates were only 19 and 27 %, respectively. Our results revealed the benefits of intercropped leguminous trees in eucalyptus plantations on soil C and N stocks. Index terms: Mixed plantations, Pseudosamanea guachapele, Eucalyptus grandis;soil organic matter, 13 C natural abundance.( RESUMO: CARBONO E NITROGÊNIO EM SOLO DE PASTAGEM REFLORESTADA COM EUCALIPTO E GUACHAPELEApesar de os teores de matéria orgânica serem normalmente baixos em solos arenosos, ela é responsável por quase a totalidade da CTC, armazenamento de água e disponibilidade de nutrientes desses solos. A avaliação de sistemas de exploração florestais alternativos, com vistas em incrementar a acumulação de C e N, devem ser incentivados. Este estudo compara plantios puros e mistos de Eucalyptus grandis e Pseudosamanea guachapele, leguminosa fixadora de N 2 , em relação os estoques de C e N do solo. Os plantios foram realizados em áreas anteriormente manejadas com Panicum maximum num Planossolo, que, por pelo menos dez anos, não recebeu qualquer fertilizante. Para estimar o C e o N estocado, foram retiradas amostras das camadas de 0-2,5; 2, 5-5,0; 5,0-7,5; 7,5-10,0; 10,0-20,0 e 20,0-40,0 cm tanto nos plantios puros e mistos, quanto na área de pasto. A técnica da abundância natural do 13 C foi utilizada na estimativa do C originado das árvores nos 10 cm superficiais. Os estoques de C e N, no plantio misto atingiu valores de 23,83 e 1,74 Mg ha -1 , respectivamente. Nos puros, de guachapele e eucalipto, e no pasto os estoques de C estimados foram de 14,20; 17,19 e 24,24 Mg ha -1 , respec...

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The Isotopic Composition of Reduced Organic Carbon

Cited by 686 publications

References 166 publications

Molecular, Radioactive and Stable Carbon Isotope Characterization of Estuarine Particulate Organic Matter

Molecular, Radioactive and Stable Carbon Isotope Characterization of Estuarine Particulate Organic Matter

Changes in the CO2 dynamics in near-surface cavities under a future warming scenario: Factors and evidence from the field and experimental findings

Soil carbon and nitrogen in pasture soil reforested with eucalyptus and guachapele

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