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Isotopic evidences for microbiologically mediated and direct C input to soil compounds from three different leaf litters during their decomposition.

Rubino M, Lubritto C, D'Onofrio A, Terrasi F, Kramer C, Gleixner G, Cotrufo MF - Environ Chem Lett (2008)

Bottom Line: Linoleic acid (PLFA 18:2omega6,9) was found to be very depleted in (13)C (delta(13)C(vsPDB) approximately from -38 to -42 per thousand) compared to all other PLFAs (delta(13)C(vsPDB) approximately from -14 to -35 per thousand).This is an indication that not all of the C derived from litter in the soil was transformed by microbes.The depletion in (13)C was also found in different classes of pyrolysis products, suggesting that the litter-derived C is incorporated in less or more chemically stable compounds, even only after 8 months decomposition.

View Article: PubMed Central - PubMed

ABSTRACT
We show the potentiality of coupling together different compound-specific isotopic analyses in a laboratory experiment, where (13)C-depleted leaf litter was incubated on a (13)C-enriched soil. The aim of our study was to identify the soil compounds where the C derived from three different litter species is retained. Three (13)C-depleted leaf litter (Liquidambar styraciflua L., Cercis canadensis L. and Pinus taeda L., delta(13)C(vsPDB) approximately -43 per thousand), differing in their degradability, were incubated on a C4 soil (delta(13)C(vsPDB) approximately -18 per thousand) under laboratory-controlled conditions for 8 months. At harvest, compound-specific isotope analyses were performed on different classes of soil compounds [i.e. phospholipids fatty acids (PLFAs), n-alkanes and soil pyrolysis products]. Linoleic acid (PLFA 18:2omega6,9) was found to be very depleted in (13)C (delta(13)C(vsPDB) approximately from -38 to -42 per thousand) compared to all other PLFAs (delta(13)C(vsPDB) approximately from -14 to -35 per thousand). Because of this, fungi were identified as the first among microbes to use the litter as source of C. Among n-alkanes, long-chain (C27-C31) n-alkanes were the only to have a depleted delta(13)C. This is an indication that not all of the C derived from litter in the soil was transformed by microbes. The depletion in (13)C was also found in different classes of pyrolysis products, suggesting that the litter-derived C is incorporated in less or more chemically stable compounds, even only after 8 months decomposition.

No MeSH data available.


Related in: MedlinePlus

δ13C values [‰]V-PDB of n-alkanes for initial soil (open square) and soil incubated with L. styraciflua (filled circle), with C. canadensis (open circle) and with P. taeda (open triangle). Error bars are standard deviation (n = 3 analytical replicates for initial soil and n = 4 experimental replicates for soils incubated with litter)
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Fig2: δ13C values [‰]V-PDB of n-alkanes for initial soil (open square) and soil incubated with L. styraciflua (filled circle), with C. canadensis (open circle) and with P. taeda (open triangle). Error bars are standard deviation (n = 3 analytical replicates for initial soil and n = 4 experimental replicates for soils incubated with litter)

Mentions: The δ13Cs of n-alkanes (C14–C32) for soils incubated with each litter species are shown in Fig. 2. The δ13Cs of n-alkanes from soil prior to incubation are also shown. Unfortunately, for a technical problem during extraction, the control soil was lost. However, we believe that the soil prior to incubation can be considered a good reference to determine the contribution of litter-derived C to n-alkanes. Here, the assumption is that n-alkanes in the control soil do not change their isotopic composition during the incubation. This will be further discussed below.Fig. 2


Isotopic evidences for microbiologically mediated and direct C input to soil compounds from three different leaf litters during their decomposition.

Rubino M, Lubritto C, D'Onofrio A, Terrasi F, Kramer C, Gleixner G, Cotrufo MF - Environ Chem Lett (2008)

δ13C values [‰]V-PDB of n-alkanes for initial soil (open square) and soil incubated with L. styraciflua (filled circle), with C. canadensis (open circle) and with P. taeda (open triangle). Error bars are standard deviation (n = 3 analytical replicates for initial soil and n = 4 experimental replicates for soils incubated with litter)
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC2837225&req=5

Fig2: δ13C values [‰]V-PDB of n-alkanes for initial soil (open square) and soil incubated with L. styraciflua (filled circle), with C. canadensis (open circle) and with P. taeda (open triangle). Error bars are standard deviation (n = 3 analytical replicates for initial soil and n = 4 experimental replicates for soils incubated with litter)
Mentions: The δ13Cs of n-alkanes (C14–C32) for soils incubated with each litter species are shown in Fig. 2. The δ13Cs of n-alkanes from soil prior to incubation are also shown. Unfortunately, for a technical problem during extraction, the control soil was lost. However, we believe that the soil prior to incubation can be considered a good reference to determine the contribution of litter-derived C to n-alkanes. Here, the assumption is that n-alkanes in the control soil do not change their isotopic composition during the incubation. This will be further discussed below.Fig. 2

Bottom Line: Linoleic acid (PLFA 18:2omega6,9) was found to be very depleted in (13)C (delta(13)C(vsPDB) approximately from -38 to -42 per thousand) compared to all other PLFAs (delta(13)C(vsPDB) approximately from -14 to -35 per thousand).This is an indication that not all of the C derived from litter in the soil was transformed by microbes.The depletion in (13)C was also found in different classes of pyrolysis products, suggesting that the litter-derived C is incorporated in less or more chemically stable compounds, even only after 8 months decomposition.

View Article: PubMed Central - PubMed

ABSTRACT
We show the potentiality of coupling together different compound-specific isotopic analyses in a laboratory experiment, where (13)C-depleted leaf litter was incubated on a (13)C-enriched soil. The aim of our study was to identify the soil compounds where the C derived from three different litter species is retained. Three (13)C-depleted leaf litter (Liquidambar styraciflua L., Cercis canadensis L. and Pinus taeda L., delta(13)C(vsPDB) approximately -43 per thousand), differing in their degradability, were incubated on a C4 soil (delta(13)C(vsPDB) approximately -18 per thousand) under laboratory-controlled conditions for 8 months. At harvest, compound-specific isotope analyses were performed on different classes of soil compounds [i.e. phospholipids fatty acids (PLFAs), n-alkanes and soil pyrolysis products]. Linoleic acid (PLFA 18:2omega6,9) was found to be very depleted in (13)C (delta(13)C(vsPDB) approximately from -38 to -42 per thousand) compared to all other PLFAs (delta(13)C(vsPDB) approximately from -14 to -35 per thousand). Because of this, fungi were identified as the first among microbes to use the litter as source of C. Among n-alkanes, long-chain (C27-C31) n-alkanes were the only to have a depleted delta(13)C. This is an indication that not all of the C derived from litter in the soil was transformed by microbes. The depletion in (13)C was also found in different classes of pyrolysis products, suggesting that the litter-derived C is incorporated in less or more chemically stable compounds, even only after 8 months decomposition.

No MeSH data available.


Related in: MedlinePlus