Movement and turnover of soil organic matter as indicated by carbon isotope measurements

O’Brien, Beverley; Stout, J. D.

doi:10.1016/0038-0717(78)90028-7

Cited by 259 publications

(150 citation statements)

References 16 publications

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“…In Figure 1 we show the Southern Hemisphere atmospheric curve for 1990 through 1996, and the data for all '4C analysis of materials. 1963;Tauber 1967) and has had more recent application in determinations of variation in &4C in contemporary and pre-bomb vegetative matter (Druffel and Griffin 1995;O'Brien and Stout 1978). Values for plant materials were also used in our determination of factors influencing rat bone values, as young shoots, fruits and grass seed make up an important component of the Rattus exulans diet (Bunn and Craig 1989;Speed 1986 Interesting information about differential carbon turnover rates, or "lag times" (Druffel and Griffin 1995) was provided by the sample of shelf fungus Polystictus, from which an unidentified species of wood mite and a Carabid beetle were also collected.…”

Section: Resultsmentioning

confidence: 99%

Factors Influencing ¹⁴C Ages of the Pacific Rat Rattus Exulans

Beavan

Sparks

1997

Radiocarbon

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ABSTRACT. An isotopic database for the Pacific/Polynesian rat (Rattus exulans) and foods that it scavenges is used to examine diet-induced 14C age variation in omnivores. We discuss a suite of 26 e14C determinations and 13C and 15N analysis for modern Pacific/Polynesian rat bone gelatin and available food items from Kapiti Island, New Zealand (40°51'S, 174°75'E). These analyses provide the first isotopic data for modern specimens of the species, collected as part of a larger project to determine potential sources of bias in unexpectedly old 14C age measurements on subfossil specimens of R. exulans from New Zealand. Stable C, N and 14C isotopic and trapping data are used to trace carbon intake via the diet of the rats in each habitat. Data from specimens linked to five specific habitats on the island indicate that modern populations of R. exulans are not in equilibrium with atmospheric values of O14C, being either enriched or depleted relative to the atmospheric curve in 1996/97, the period of collection. The e14C values recorded for R. exulans are associated with diet, and result from variation in e14C values found in animal-protein food items available to a scavenging omnivore. The titer of carbon deviating from atmospheric values is believed to be derived from the essential amino acids in the protein-rich foods of the rat diet.Present evidence suggests that the depletion required to affect 14C ages limits the possibility that diet introduces dramatic offsets from true ages. Marine diets, for example, would have a variable effect on ages for terrestrial omnivores, contraindicating the application of a standard marine correction for such specimens. We suggest that to identify the extent to which diet may influence the 14C age in a given specimen of terrestrial omnivore, the separation and dating of essential amino acids vs. a nonessential amino, such as glycine, be applied.

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Section: Resultsmentioning

confidence: 99%

Factors Influencing ¹⁴C Ages of the Pacific Rat Rattus Exulans

Beavan

Sparks

1997

Radiocarbon

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“…Models describing the dynamics of accumulation and turnover of organic carbon generally recognize components of soil organic matter (SOM) that turn over on annual (active), decadal (slow) and centennial to millennial (passive) time scales (Jenkinson and Raynor 1977;O'Brien and Stout 1978;Parton et al 1987;Jenkinson, Adams and Wild 1991;Potter et al 1993;Townsend, Vitousek and Trumbore 1995;Schimel et al 1994). Although these concepts have proven useful in explaining the magnitude and timing of changes in SOM following a perturbation such as land clearing for cultivation (Parton et a1.1987;Cambardella and Elliott 1993;Davidson and Ackerman 1993;Schimel et al 1994), no recognized method now exists for determining how to apportion SOM into compartments that turn over on different time scales.…”

Section: Introductionmentioning

confidence: 99%

Comparison of Fractionation Methods for Soil Organic Matter ¹⁴C Analysis

1996

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ABSTRACT. 14( measurements provide a useful test for determining the degree to which chemical and physical fractionation of soil organic matter (SOM) are successful in separating labile and refractory organic matter components. Results from AMS measurements of fractionated SOM made as part of several projects are summarized here, together with suggestions for standardization of fractionation procedures. Although no single fractionation method will unequivocally separate SOM into components cycling on annual, decadal and millennial time scales, a combination of physical (density separation or sieving) and chemical separation methods (combined acid and base hydrolysis) provides useful constraints for models of soil carbon dynamics in several soil types.

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“…Let us assume that the soil organic carbon reservoir is made up by at least fast and slow decomposable components. The fast, and thus young, component is located in the top soil layer, whereas in deeper layers, the slow and old component predominates (O'Brien & Stout, 1978; Harkness, Harrison & Bacon, 1986;O'Brien, 1986). The turnover time of the fast (1 yr) and the slow (100 yr) components and the downward velocity of soil organic matter can be adequately adjusted to model the 14C depth distribution in a forest soil to a satisfactory degree (DOrr & Munnich, 1986).…”

Section: Introductionmentioning

confidence: 99%

Downward Movement of Soil Organic Matter and Its Influence on Trace-Element Transport (210Pb, 137Cs) in the Soil

Dörr

Münnich

1989

Radiocarbon

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ABSTRACT. Data on depth distribution and 14C content of soil organic carbon, and on soil CO2 production in forest ecosystems are presented and discussed. Downward movement and turnover of soil organic matter is estimated from a box chain model. The downward transfer velocity of soil organic material depends on the litter material composition and on the annual rate of microbial decomposition. Depth distribution of 210Pb and 137Cs was measured. The identical transfer velocity of 210Pb and soil organic material suggests that lead transport is due to movement of the organic material itself. Lead in organic-rich soils obviously is bound rather tightly to the organic carrier by ion exchange or organic complexing. 137Cs migration depends on the turnover and downward movement of soil organic material. Results suggest that cesium is not transported only by the downward movement of solid organic matter, but, due to chemical exchange between the organic and hydrous phases, travels faster than organic matter.

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Movement and turnover of soil organic matter as indicated by carbon isotope measurements

Cited by 259 publications

References 16 publications

Factors Influencing ¹⁴C Ages of the Pacific Rat Rattus Exulans

Factors Influencing ¹⁴C Ages of the Pacific Rat Rattus Exulans

Comparison of Fractionation Methods for Soil Organic Matter ¹⁴C Analysis

Downward Movement of Soil Organic Matter and Its Influence on Trace-Element Transport (210Pb, 137Cs) in the Soil

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Movement and turnover of soil organic matter as indicated by carbon isotope measurements

Cited by 259 publications

References 16 publications

Factors Influencing 14C Ages of the Pacific Rat Rattus Exulans

Factors Influencing 14C Ages of the Pacific Rat Rattus Exulans

Comparison of Fractionation Methods for Soil Organic Matter 14C Analysis

Downward Movement of Soil Organic Matter and Its Influence on Trace-Element Transport (210Pb, 137Cs) in the Soil

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Factors Influencing ¹⁴C Ages of the Pacific Rat Rattus Exulans

Factors Influencing ¹⁴C Ages of the Pacific Rat Rattus Exulans

Comparison of Fractionation Methods for Soil Organic Matter ¹⁴C Analysis