TY - JOUR
T1 - Molecular organic tracers of biogeochemical process in a saline meromictic lake
AU - Schouten, S.
AU - Rijpstra, W. I C
AU - Kok, M.
AU - Hopmans, E. C.
AU - Summons, R. E.
AU - Volkman, J. K.
AU - Sinninghe Damsté, J. S.
PY - 2001
Y1 - 2001
N2 - The chemical structures, distribution and stable carbon isotopic compositions of lipids in a sediment core taken in meromictic Ace Lake (Antartica) were analyzed to trace past biogeochemical cycling. Biomarkers from methanogenic archaea, methanotrophic bacteria and photosynthetic green sulfur bacteria were unambiguously assigned using organic geochemical understanding and by reference to what is known about the lake's present-day ecosystem. For instance, saturated and unsaturated 2,6,10,15,19,-pentamethylicosane, archaeol and sn2-hydroxyarchaeol were derived from methanogenic archaea. Carotenoid analysis revealed chlorobactene and isorenieratene derived from the green-colored and brown-colored strains of the green sulfur bacteria (Chlorobiaceae): Isotopic analyses showed that they were 13C-enriched. Phytenes appear to be derived from photoautotrophs that use the Calvin-Benson cycle, while phytane has a different source. possibly within the archaea. The most 13C-depleted compounds (ca.-55‰) identified were 4-methyl-5α cholest-8(14)-en-3β-ol, identified using an authentic standard, and co-occurring 4-methylsteradienes: These originate from the aerobic methanotrophic bacterium Methylosphaera hansonii. Lipids of photoautotrophic origin, steranes and alkenones, are relatively depleted (ca.-28 to -36‰) whilst archaeal biomarkers are relatively enriched in 13C (ca.-17 to -25‰). The structural and carbon isotope details of sedimentary lipids thus revealed aspects of in situ biogeochemical processes such as methane generation and oxidation and phototrophic sulfide oxidation.
AB - The chemical structures, distribution and stable carbon isotopic compositions of lipids in a sediment core taken in meromictic Ace Lake (Antartica) were analyzed to trace past biogeochemical cycling. Biomarkers from methanogenic archaea, methanotrophic bacteria and photosynthetic green sulfur bacteria were unambiguously assigned using organic geochemical understanding and by reference to what is known about the lake's present-day ecosystem. For instance, saturated and unsaturated 2,6,10,15,19,-pentamethylicosane, archaeol and sn2-hydroxyarchaeol were derived from methanogenic archaea. Carotenoid analysis revealed chlorobactene and isorenieratene derived from the green-colored and brown-colored strains of the green sulfur bacteria (Chlorobiaceae): Isotopic analyses showed that they were 13C-enriched. Phytenes appear to be derived from photoautotrophs that use the Calvin-Benson cycle, while phytane has a different source. possibly within the archaea. The most 13C-depleted compounds (ca.-55‰) identified were 4-methyl-5α cholest-8(14)-en-3β-ol, identified using an authentic standard, and co-occurring 4-methylsteradienes: These originate from the aerobic methanotrophic bacterium Methylosphaera hansonii. Lipids of photoautotrophic origin, steranes and alkenones, are relatively depleted (ca.-28 to -36‰) whilst archaeal biomarkers are relatively enriched in 13C (ca.-17 to -25‰). The structural and carbon isotope details of sedimentary lipids thus revealed aspects of in situ biogeochemical processes such as methane generation and oxidation and phototrophic sulfide oxidation.
UR - http://www.scopus.com/inward/record.url?scp=0035015718&partnerID=8YFLogxK
U2 - 10.1016/S0016-7037(00)00627-X
DO - 10.1016/S0016-7037(00)00627-X
M3 - Article
AN - SCOPUS:0035015718
SN - 0016-7037
VL - 65
SP - 1629
EP - 1640
JO - Geochimica et Cosmochimica Acta
JF - Geochimica et Cosmochimica Acta
IS - 10
ER -