 |
| Titel |
Implications for chloro- and pheopigment synthesis and preservation from combined compound-specific δ¹³C, δ¹⁵N, and δ¹⁴C analysis |
| VerfasserIn |
S. Kusch, Y. Kashiyama, N. O. Ogawa, M. Altabet, M. Butzin, J. Friedrich, N. Ohkouchi, G. Mollenhauer |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1726-4170
|
| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 7, no. 12 ; Nr. 7, no. 12 (2010-12-23), S.4105-4118 |
| Datensatznummer |
250005111
|
| Publikation (Nr.) |
 copernicus.org/bg-7-4105-2010.pdf |
|
|
|
|
|
| Zusammenfassung |
| Chloropigments and their derivative pheopigments preserved in sediments can
directly be linked to photosynthesis. Their carbon and nitrogen stable
isotopic compositions have been shown to be a good recorder of recent and
past surface ocean environmental conditions tracing the carbon and nitrogen
sources and dominant assimilation processes of the phytoplanktonic
community. In this study we report results from combined compound-specific
radiocarbon and stable carbon and nitrogen isotope analysis to examine the
time-scales of synthesis and fate of chlorophyll-a and its degradation
products pheophytin-a, pyropheophytin-a, and
132,173-cyclopheophorbide-a-enol until burial in Black Sea core-top
sediments. The pigments are mainly of marine phytoplanktonic origin as
implied by their stable isotopic compositions. Pigment δ15N
values indicate nitrate as the major uptake substrate but 15N-depletion
towards the open marine setting indicates either contribution from
N2-fixation or direct uptake of ammonium from deeper waters.
Radiocarbon concentrations translate into minimum and maximum pigment ages
of approximately 40 to 1200 years. This implies that protective mechanisms
against decomposition such as association with minerals, storage in deltaic
anoxic environments, or eutrophication-induced hypoxia and light limitation
are much more efficient than previously thought. Moreover, seasonal
variations of nutrient source, growth period, and habitat and their
associated isotopic variability are likely at least as strong as long-term
trends. Combined triple isotope analysis of sedimentary chlorophyll and its
primary derivatives is a powerful tool to delineate biogeochemical and
diagenetic processes in the surface water and sediments, and to assess their
precise time-scales. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|