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| Titel |
Selective preservation of organic matter in marine environments; processes and impact on the sedimentary record |
| VerfasserIn |
K. A. F. Zonneveld, G. J. M. Versteegh, S. Kasten, T. I. Eglinton, K.-C. Emeis, C. Huguet, B. P. Koch, G. J. Lange, J. W. Leeuw, J. J. Middelburg, G. Mollenhauer, F. G. Prahl, J. Rethemeyer, S. G. Wakeham |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1726-4170
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| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 7, no. 2 ; Nr. 7, no. 2 (2010-02-05), S.483-511 |
| Datensatznummer |
250004485
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| Publikation (Nr.) |
 copernicus.org/bg-7-483-2010.pdf |
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| Zusammenfassung |
The present paper is the result of a workshop sponsored by the DFG Research
Center/Cluster of Excellence MARUM "The Ocean in the Earth System", the
International Graduate College EUROPROX, and the Alfred Wegener Institute
for Polar and Marine Research. The workshop brought together specialists on
organic matter degradation and on proxy-based environmental reconstruction.
The paper deals with the main theme of the workshop, understanding the
impact of selective degradation/preservation of organic matter (OM) in
marine sediments on the interpretation of the fossil record. Special
attention is paid to (A) the influence of the molecular composition of OM in
relation to the biological and physical depositional environment, including
new methods for determining complex organic biomolecules, (B) the impact of
selective OM preservation on the interpretation of proxies for marine
palaeoceanographic and palaeoclimatic reconstruction, and (C) past marine
productivity and selective preservation in sediments.
It appears that most of the factors influencing OM preservation have been
identified, but many of the mechanisms by which they operate are partly, or
even fragmentarily, understood. Some factors have not even been taken
carefully into consideration. This incomplete understanding of OM breakdown
hampers proper assessment of the present and past carbon cycle as well as
the interpretation of OM based proxies and proxies affected by OM breakdown.
To arrive at better proxy-based reconstructions "deformation functions"
are needed, taking into account the transport and diagenesis-related
molecular and atomic modifications following proxy formation.
Some emerging proxies for OM degradation may shed light on such deformation
functions. The use of palynomorph concentrations and selective changes in
assemblage composition as models for production and preservation of OM may
correct for bias due to selective degradation. Such quantitative assessment
of OM degradation may lead to more accurate reconstruction of past
productivity and bottom water oxygenation.
Given the cost and effort associated with programs to recover sediment cores
for paleoclimatological studies, as well as with generating proxy records,
it would seem wise to develop a detailed sedimentological and diagenetic
context for interpretation of these records. With respect to the latter,
parallel acquisition of data that inform on the fidelity of the proxy
signatures and reveal potential diagenetic biases would be of clear value. |
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