Microbial lipid signatures in Arctic deltaic sediments - insights into methane cycling and climate variability ...
Glycerol Dialkyl Glycerol Tetraethers (GDGTs) are ubiquitous biomolecules whose structural diversity or isotopic composition is increasingly used to reconstruct environmental changes such as air temperatures or pCO2. Isoprenoid GDGTs, in particular GDGT-0, are biosynthesized by a large range of Arch...
| Main Authors: | , , , , |
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| Format: | Text |
| Language: | English |
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ETH Zurich
2020
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| Subjects: | |
| Online Access: | https://dx.doi.org/10.3929/ethz-b-000450874 http://hdl.handle.net/20.500.11850/450874 |
| Summary: | Glycerol Dialkyl Glycerol Tetraethers (GDGTs) are ubiquitous biomolecules whose structural diversity or isotopic composition is increasingly used to reconstruct environmental changes such as air temperatures or pCO2. Isoprenoid GDGTs, in particular GDGT-0, are biosynthesized by a large range of Archaea. To assess the potential of GDGT-0 as a tracer of past methane cycle variations, three sediment cores from the Mackenzie River Delta have been studied for iGDGT and diploptene distribution and stable carbon signature. The absence of crenarchaeol, high GDGT-0 vs crenarchaeol ratio, and 13C-enriched carbon signature of GDGT-0 indicate production by acetoclastic methanogens as well as heterotrophic Archaea. The oxidation of methane seems to be dominated by bacteria as indicated by the high abundance of 13C-depleted diploptene. Branched GDGTs, thought to be produced by heterotrophic bacteria, are dominated by hexa- and penta-methylated 5- and 6-methyl compounds. The presence of 5,6-methyl isomer IIIa’’ points ... : EarthArXiv ... |
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