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| Titel |
Bacteriohopanepolyols record stratification, nitrogen fixation and other biogeochemical perturbations in Holocene sediments of the central Baltic Sea |
| VerfasserIn |
M. Blumenberg, C. Berndmeyer, M. Moros, M. Muschalla, O. Schmale, V. Thiel |
| 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 ; 10, no. 4 ; Nr. 10, no. 4 (2013-04-23), S.2725-2735 |
| Datensatznummer |
250018216
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| Publikation (Nr.) |
 copernicus.org/bg-10-2725-2013.pdf |
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| Zusammenfassung |
| The Baltic Sea, one of the world's largest brackish-marine basins,
established after deglaciation of Scandinavia about 17 000 to 15 000 yr ago.
In the changeable history of the Baltic Sea, the initial freshwater
system was connected to the North Sea about 8000 yr ago and the modern
brackish-marine setting (Littorina Sea) was established. Today, a relatively
stable stratification has developed in the water column of the deep basins due
to salinity differences. Stratification is only occasionally interrupted by
mixing events, and it controls nutrient availability and growth of specifically
adapted microorganisms and algae. We studied bacteriohopanepolyols (BHPs),
lipids of specific bacterial groups, in a sediment core from the central
Baltic Sea (Gotland Deep) and found considerable differences between the
distinct stages of the Baltic Sea's history. Some individual
BHP structures indicate contributions from as yet unknown
redoxcline-specific bacteria (bacteriohopanetetrol isomer), methanotrophic
bacteria (35-aminobacteriohopanetetrol), cyanobacteria (bacteriohopanetetrol
cyclitol ether isomer) and from soil bacteria (adenosylhopane) through
allochthonous input after the Littorina transgression, whereas the origin of
other BHPs in the core has still to be identified. Notably high BHP
abundances were observed in the deposits of the brackish-marine Littorina
phase, particularly in laminated sediment layers. Because these sediments
record periods of stable water column stratification, bacteria specifically
adapted to these conditions may account for the high portions of BHPs. An
additional and/or accompanying source may be nitrogen-fixing
(cyano)bacteria, which is indicated by a positive correlation of BHP
abundances with Corg and δ15N. |
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