Controls on the stable hydrogen isotopic composition of alkenones

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PALEOSALINITY RECONSTRUCTIONS BASED ON STABLE
HYDROGEN ISOTOPIC COMPOSITION OF ALGAL
BIOMARKERS. RECENT DEVELOPMENTS! Marcel T.J.
van der Meer (NIOZ) Marianne Baas (NIOZ) Ellen
Hopmans (NIOZ) Albert Benthien (AWI) Ingrid
Zondervan (AWI) Jelle Bijma (AWI) Jaap S.
Sinninghe Damsté (NIOZ/UU) Stefan Schouten (NIOZ)
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? Testing climate models for future climate
change critically depend on our ability to
quantitatively reconstruct past climate. ?
Paleosalinity is the single most important
oceanographic parameter which currently can still
not be accurately quantified from sedimentary
records.
? dDwater correlates strongly with salinity.
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Estimating dD water from dD alkenones.
? Paul (2002) relatively constant
fractionation of 232 between dDwater and the
dD of C37 alkenones produced by E. huxleyi. ?
Englebrecht and Sachs (2005) reported a similar
fractionation of 225 . ? Schouten et al.
(2006) have shown that hydrogen isotope
fractionation by E. huxleyi and Gephyrocapsa
oceanica depends on - dDwater - salinity
- growth rate
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aalkenones-water versus salinity
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aalkenones-water versus growth rate
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a Heterocapsa triquetra dinosterol versus salinity
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Black Sea
BC53 Cruise 134/8 R/V Knorr 1988
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Shift from Unit II to Unit I The invasion of
E. huxleyi has been attributed to a increase in
salinity from below 11 in Unit II to above 11 in
Unit I (Bukry, 1974)
varved coccolith ooze Unit I
163560
1st occurrence of E. Huxleyi
Salinity gt 11
transition sapropel
Salinity lt 11
organic-rich sapropel Unit II
2720160 yrs BP
Jones and Gagnon, 1994
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dD of C37 alkenones from the Black Sea
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Paleo-salinity estimates
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Dinocysts
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dD of C37 alkenones and of dinosterol from the
Black Sea.
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Paleo-salinity estimates based on alkenones and
on dinosterol
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Black Sea salinity gradient
Leonov 2003
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Isotope analysis of individual alkenones better
or not?
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a C37 alkenones-water versus temperature.
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dD of individual alkenones versus temperature
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dD of individual alkenones versus Uk37.
dD ( vs. VSMOW)
Uk37
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dD of individual alkenones versus salinity.
dD ( vs. VSMOW)
Salinity
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C372
The idea!
Warm
C372
C373
C372
C373
C373
C372
Cold
low dD
High dD
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Red Sea TEX86 and qualitative salinity indicator.
Bab el Mandeb
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Sampling sites
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TEX86
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TEX86
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TEX86
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Relationship between TEX86 index and sea surface
temperature and salinity in the Red Sea
Southern Red Sea
Northern Red Sea
TEX86
TEX86
Global calibration
Gulf of Aden
Salinity
SST (C)
Trommer et al., in preparation
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Interpretation of the TEX86 index in the Red Sea
Trommer et al., in preparation
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Calculated contribution of the endemic Red Sea
Crenarchaeota population.
Trommer et al., in preparation
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Qualitative salinity indicator diether membrane
lipid produced by halophilic Archaea.
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Qualitative salinity indicator
S lt 38.6
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Light experimentaalkenones-water versus growth
rate
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Light experimentaalkenones-water versus growth
rate
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Light experimentdD versus light intensity
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Light experimentdD versus light intensity
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