Relative stability of soil carbon revealed by shifts in δ&amp;lt;sup&amp;gt;15&amp;lt;/sup&amp;gt;N and C:N ratio

Conen, Franz; Zimmermann, Michael; Leifeld, Jens; Seth, Barbara; Alewell, Christine

doi:10.5194/bg-5-123-2008

Cited by 68 publications

(36 citation statements)

References 29 publications

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“…δ 13 C) and nitrogen (i.e. δ 15 N) served as useful tools to determine sources and sinks of carbon, nitrogen or sediments (Alewell et al, 2008;Buck and Monger, 1999;Papanicolaou et al, 2003;Schaub and Alewell, 2009;Turnbull et al, 2008;Fox and Papanicolaou, 2007;Jacinthe et al, 2009). They are also useful for process identification and even process quantification (Conen et al, 2007(Conen et al, , 2008.…”

Section: K Meusburger Et Al: Stable Isotopes and Fallout Radionuclimentioning

confidence: 99%

Combined use of stable isotopes and fallout radionuclides as soil erosion indicators in a forested mountain site, South Korea

et al. 2013

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Abstract. The aim of this study is to assess and to validate the suitability of the stable nitrogen and carbon isotope signature as soil erosion indicators in a mountain forest site in South Korea. Our approach is based on the comparison of the isotope signature of "stable" landscape positions (reference sites), which are neither affected by erosion nor deposition, with eroding sites. For undisturbed soils we expect that the enrichment of δ15N and δ13C with soil depth, due to fractionation during decomposition, goes in parallel with a decrease in nitrogen and carbon content. Soil erosion processes potentially weaken this correlation. The 137Cs method and the Revised Universal Soil Loss Equation (RUSLE) were applied for the soil erosion quantification. Erosion rates obtained with the 137Cs method range from 0.9 t ha−1 yr−1 to 7 t ha−1 yr−1. Considering the steep slopes of up to 40° and the erosive monsoon events (R factor of 6600 MJ mm ha−1 h−1 yr –1), the rates are plausible and within the magnitude of the RUSLE-modeled soil erosion rates, varying from 0.02 t ha−1 yr−1 to 5.1 t ha−1 yr−1. The soil profiles of the reference sites showed significant (p < 0.0001) correlations between nitrogen and carbon content and its corresponding δ15N and δ13C signatures. In contrast, for the eroding sites this relationship was weaker and for the carbon not significant. These results confirm the usefulness of the stable carbon isotope signature as a qualitative indicator for soil disturbance. We could show further that the δ15N isotope signature can be used similarly for uncultivated sites. We thus propose that the stable δ15N and δ13C signature of soil profiles could serve as additional indicators confirming the accurate choice of the reference site in soil erosion studies using the 137Cs method.

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Section: K Meusburger Et Al: Stable Isotopes and Fallout Radionuclimentioning

confidence: 99%

Combined use of stable isotopes and fallout radionuclides as soil erosion indicators in a forested mountain site, South Korea

et al. 2013

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“…Obviously, the time period that is archived in GDGTs from a single soil horizon is a function of GDGT accumulation and erosion rates, parameters that were not assessed for the Lake Cadagno Region. At a depth of a few decimetres only, organic carbon in Alpine soils may already be several hundred years old (Conen et al, 2008). It thus seems likely that mixing of GDGTs from deeper horizons with top soil (i.e.…”

Section: The Middle and Early Holocene Prior To 2 Kyr Bpmentioning

confidence: 99%

Bacterial GDGTs in Holocene sediments and catchment soils of a high Alpine lake: application of the MBT/CBT-paleothermometer

et al. 2012

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“…2c). C/Na generally decrease with increasing decomposition while δ 15 N values increase (Conen et al, 2008). The correlation between mean C/Na and mean δ 15 N of SS is significantly negative (ρ = −0.8).…”

Section: Spatial and Temporal Dynamic Of C/namentioning

confidence: 82%

“…5). These low values indicate young, poorly-decomposed material (Conen et al, 2008). The riverbed sediment probably originates mainly from the bedrock molasse.…”

Section: Carbon and Nitrogen Isotopes For Tracing Suspended Sediment mentioning

confidence: 99%

Organic matter dynamics and stable isotope signature as tracers of the sources of suspended sediment

Wildhaber¹,

Liechti²,

Alewell³

2012

Biogeosciences

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Abstract. Suspended sediment (SS) and organic matter in rivers can harm brown trout Salmo trutta by affecting the health and fitness of free swimming fish and by causing siltation of the riverbed. The temporal and spatial dynamics of sediment, carbon (C), and nitrogen (N) during the brown trout spawning season in a small river of the Swiss Plateau were assessed and C isotopes as well as the C/N atomic ratio were used to distinguish autochthonous and allochthonous sources of organic matter in SS loads. The visual basic program IsoSource with 13 C tot and 15 N as input isotopes was used to quantify the temporal and spatial sources of SS. Organic matter concentrations in the infiltrated and suspended sediment were highest during low flow periods with small sediment loads and lowest during high flow periods with high sediment loads. Peak values in nitrate and dissolved organic C were measured during high flow and high rainfall, probably due to leaching from pasture and arable land. The organic matter was of allochthonous sources as indicated by the C/N atomic ratio and δ 13 C org . Organic matter in SS increased from up-to downstream due to an increase of pasture and arable land downstream of the river. The mean fraction of SS originating from upper watershed riverbed sediment decreased from up to downstream and increased during high flow at all measuring sites along the course of the river. During base flow conditions, the major sources of SS are pasture, forest and arable land. The latter increased during rainy and warmer winter periods, most likely because both triggered snow melt and thus erosion. The measured increase in DOC and nitrate concentrations during high flow support these modeling results. Enhanced soil erosion processes on pasture and arable land are expected with increasing heavy rain events and less snow during winter seasons due to climate change. Consequently, SS and organic matter in the river will increase, which will possibly affect brown trout negatively.

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Relative stability of soil carbon revealed by shifts in δ<sup>15</sup>N and C:N ratio

Cited by 68 publications

References 29 publications

Combined use of stable isotopes and fallout radionuclides as soil erosion indicators in a forested mountain site, South Korea

Combined use of stable isotopes and fallout radionuclides as soil erosion indicators in a forested mountain site, South Korea

Bacterial GDGTs in Holocene sediments and catchment soils of a high Alpine lake: application of the MBT/CBT-paleothermometer

Organic matter dynamics and stable isotope signature as tracers of the sources of suspended sediment

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