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| Titel |
Testing the sensitivity of stable carbon isotopes of sub-fossil Sphagnum cellulose to past climate variability: a two millennia high resolution stable carbon isotope time series from the peat deposit "Dürres Maar", Germany |
| VerfasserIn |
Robert Moschen, Norbert Kuhl, Sabrina Peters, Heinz Vos, Andreas Lücke |
| Konferenz |
EGU General Assembly 2010
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 12 (2010) |
| Datensatznummer |
250040255
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| Zusammenfassung |
| Peat deposits are terrestrial archives of environmental changes and climate dynamics over
time. They are widely distributed and cover a large part of the earth’s land surface often
within human habitat and, thus, form an excellent basis for evaluating ecosystem and climate
dynamics by multiple geochemical and biological methods. Records of the stable carbon
composition of cellulose separately extracted from selected Sphagnum plant components
(δ13CSphagnum) from the kettle-hole type peat deposit of “Dürres Maar” are presented.
Manually separated Sphagnum stems, branches and the small leaves covering Sphagnum
branches were used for cellulose extraction and subsequent isotope measurements, because
intra-plant δ13CSphagnum variability between different physical components of individual
modern plants has been described (Loader et al. 2007). We observed the same isotopic
offset between single plant components of sub-fossil Sphagnum plant components
which is statistically highly significant and observable down-core (Moschen et al.
2009). Using the size fraction of 355-630 μm, which almost exclusively consists
of single Sphagnum leaves, allows to derive environmental and climate signals
based on a plant response to external controls, presumably including temperature
and relative humidity. Because down-core changes in the ratio of different plant
components in the peat profile seem probable, erroneous interpretations of isotope
records are likely if no differentiation into single Sphagnum plant components is
possible.
A high resolution time series of δ13CSphagnum is presented covering the last two
millennia, tracing decadal to sub-decadal past environmental and climate dynamics. The
thickness of the water film surrounding the chloroplasts of Sphagnum plants has been
suggested as the most important factor influencing δ13CSphagnum. This points to
bog surface wetness which is primarily driven by precipitation and evaporation
temperature as the major control of δ13CSphagnum. The close coupling of several
environmental factors to air temperature, however, presumably also results in an indirect
dependency of δ13CSphagnum on air temperature, since strong correlation between
δ13CSphagnum of modern Sphagnum plants and local air temperature during the
growing season has been observed for altitudinal transects (Skrzypek et al. 2007).
We applied potential relationships between our δ13CSphagnum and climatological
parameters as deducible from existing calibration data sets. Results are compared with
quantitative climate reconstructions based on well established palynological methods
applied to the same core from “Dürres Maar”. Additionally, comparisons of the
δ13CSphagnum record with time series of meteorological observations are presented
to review the potential relationships between δ13CSphagnum and climatological
parameters.
References:
Loader, N.L., McCarroll, D., van der Knaap, W.O., Robertson, I. and Gagen, M.,
(2007): Characterizing carbon isotopic variability in Sphagnum. The Holocene 17:
403-410.
Skrzypek, G., Kalużny, A., Wojtuń, B. and Jędrysek, M.-O., (2007): The carbon stable
isotopic composition of mosses: A record of temperature variation. Organic Geochemistry
38: 1770-1781.
Moschen, R. et al. (2009): Stable carbon and oxygen isotopes in sub-fossil Sphagnum:
Assessment of their applicability for palaeoclimatology. Chemical Geology 259: 262-272. |
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