25th International Meeting on Organic Geochemistry IMOG 2011

P-179
Tetraether membrane lipid distributions in lacustrine sediments:
a study of 28 lakes in the Yangtze floodplain (SE China)
Li Jingjing, Yang Huan, Qin Yangmin, Huang Junhua, Xie Shucheng
China University of Geosciences, Wuhan, China (corresponding author:ljjvalerie@gmail.com)
Recently, several climate and environmental proxies
based on glycerol dialkyl glycerol tetraethers
(GDGTs) from Archaea and Bacteria have been
developed and applied in diverse environments
(Powers et al., 2004; Weijers et al., 2006). However,
there are many unknown questions about the source
and mechanism of GDGTs. Do the chemical and
physical property (i.e. TP, TN, DO, COD, the
concertration of Mg 2+ , Cl - , Ca 2+ , SO4 2- , etc.) of lake
sediments influence the GDGTs the distribution? In
this study, we studied the distribution of GDGTs in the
surface sediment of 28 lakes in the Yangtze floodplain
(SE China). A comparison has been made to testify
the chemical and physical property and GDGTs
distribution of lake sediments. It suggests the
chemical and physical property do affect the
distribution of GDGTs, while lakes with exceptional
chemical and physical property are consistent with the
abnormal GDGTs distribution. Compared to bacterialderived
branched GDGTs, the isoprenoid GDGTs
derived from archaea were less affected. The results
indicate the property of lake sediments may influence
the habitats of bacteria and archaea, which may lead
to the distinct distribution of GDGTs from different
lakes. Further studies will determine which property
would affect the bacteria and archaea activity.
References
Powers, L.A., Werne, J.P., Johnson, T.C., Hopmans,
E.C., Damste, J.S.S., Schouten, S., 2004.
Crenarchaeotal membrane lipids in lake sediments: A
new paleotemperature proxy for continental
paleoclimate reconstruction? Geology 32, 613-616.
Weijers, J.W.H., Schouten, S., Spaargaren, O.C.,
Sinninghe Damst? Jaap, S., 2006. Occurrence and
distribution of tetraether membrane lipids in soils:
Implications for the use of the TEX86 proxy and the
BIT index. Organic Geochemistry 37, 1680-1693.
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