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| Titel |
Do variations in the δ¹³C of soil phospholipid fatty acids indicate changes in substrate use with climate warming? |
| VerfasserIn |
Lukas Kohl, Jérôme Laganière, Kate Edwards, Christoph Lehmeier, Kyungjin Min, Sharon A. Billings, Ford Ballantyne, Geert Van Biesen, Penny L. Morrill, Susan E. Ziegler |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250096697
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| Publikation (Nr.) |
 EGU/EGU2014-12210.pdf |
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| Zusammenfassung |
| The effect of climate warming on the microbial mineralization of soil organic carbon (SOC)
remains a key uncertainty in biogeochemical models. In particular, it remains unclear whether
microbial substrate use patterns change with climate. The carbon isotopic signature (δ13C) of
soil microbial phospholipid fatty acids (δ13CPLFA) can provide insight into substrate
utilization patterns in situ without manipulations unavoidable in soil incubation experiments.
The interpretation of δ13CPLFA, however, is limited by gaps in our understanding of
the isotopic fractionation associated with PLFA biosynthesis, and in particular,
whether this fractionation changes with growth temperature. Characterizing the
principles controlling δ13CPLFA under controlled laboratory conditions can help with
the interpretation of field measurements of temperature effects on microbial SOC
assimilation.
We measured δ13CPLFA from field soils in two regions along a boreal climate transect,
which differ by 4.5 °C mean annual temperature. In each region, the organic (L, F, H) and
mineral (B; top 10cm) soil horizons were sampled at three locations chosen for
similar vegetation (balsam fir), stand age, elevation, and soil type (humo-ferric
podzol).
Soils from both regions had similar bulk SOC δ13C and exhibited an increase with depth
from -29.5±0.4 to -26.5±0.6o. Despite the similar δ13C of SOC, PLFA in the organic
horizons from the warmer region were more enriched in 13C relative to those from the colder
region.In a model that used region, horizon and the individual PLFA as predictors, we found
that region had a subtle (0.7o), but highly significant (p |
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