TY  - JOUR
A1  - Sachse, Dirk
A1  - Billault, Isabelle
A1  - Bowen, Gabriel J.
A1  - Chikaraishi, Yoshito
A1  - Dawson, Todd E.
A1  - Feakins, Sarah J.
A1  - Freeman, Katherine H.
A1  - Magill, Clayton R.
A1  - McInerney, Francesca A.
A1  - van der Meer, Marcel T. J.
A1  - Polissar, Pratigya
A1  - Robins, Richard J.
A1  - Sachs, Julian P.
A1  - Schmidt, Hanns-Ludwig
A1  - Sessions, Alex L.
A1  - White, James W. C.
A1  - West, Jason B.
A1  - Kahmen, Ansgar
ED  - Jeanloz, R
T1  - Molecular Paleohydrology interpreting the Hydrogen- Isotopic Composition of Lipid Biomarkers from Photosynthesizing Organisms
JF  - Annual review of earth and planetary sciences
JF  - Annual Review of Earth and Planetary Sciences
N2  - Hydrogen-isotopic abundances of lipid biomarkers are emerging as important proxies in the study of ancient environments and ecosystems. A decade ago, pioneering studies made use of new analytical methods and demonstrated that the hydrogen-isotopic composition of individual lipids from aquatic and terrestrial organisms can be related to the composition of their growth (i.e., environmental) water. Subsequently, compound-specific deuterium/hydrogen (D/H) ratios of sedimentary biomarkers have been increasingly used as paleohydrological proxies over a range of geological timescales. Isotopic fractionation observed between hydrogen in environmental water and hydrogen in lipids, however, is sensitive to biochemical, physiological, and environmental influences on the composition of hydrogen available for biosynthesis in cells. Here we review the factors and processes that are known to influence the hydrogen-isotopic compositions of lipids-especially n-alkanes-from photosynthesizing organisms, and we provide a framework for interpreting their D/H ratios from ancient sediments and identify future research opportunities.
KW  - paleoclimate
KW  - paleoclimate proxy
KW  - deuterium
KW  - organic geochemistry
Y1  - 2012
SN  - 978-0-8243-2040-9
U6  - https://doi.org/10.1146/annurev-earth-042711-105535
SN  - 0084-6597
VL  - 40
IS  - 1
SP  - 221
EP  - 249
PB  - Annual Reviews
CY  - Palo Alto
ER  - 
TY  - JOUR
A1  - Gamarra, B.
A1  - Sachse, Dirk
A1  - Kahmen, A.
T1  - Effects of leaf water evaporative H-2-enrichment and biosynthetic fractionation on leaf wax n-alkane H-2 values in C3 and C4 grasses
JF  - Plant, cell & environment : cell physiology, whole-plant physiology, community physiology
N2  - Leaf wax n-alkane H-2 values carry important information about environmental and ecophysiological processes in plants. However, the physiological and biochemical drivers that shape leaf wax n-alkane H-2 values are not completely understood. It is particularly unclear why n-alkanes in grasses are typically H-2-depleted compared with plants from other taxonomic groups such as dicotyledonous plants and why C3 grasses are H-2-depleted compared with C4 grasses. To resolve these uncertainties, we quantified the effects of leaf water evaporative H-2-enrichment and biosynthetic hydrogen isotope fractionation on n-alkane H-2 values for a range of C3 and C4 grasses grown in climate-controlled chambers. We found that only a fraction of leaf water evaporative H-2-enrichment is imprinted on the leaf wax n-alkane H-2 values in grasses. This is interesting, as previous studies have shown in dicotyledonous plants a nearly complete transfer of this H-2-enrichment to the n-alkane H-2 values. We thus infer that the typically observed H-2-depletion of n-alkanes in grasses (as opposed to dicots) is because only a fraction of the leaf water evaporative H-2-enrichment is imprinted on the H-2 values. Our experiments also show that differences in n-alkane H-2 values between C3 and C4 grasses are largely the result of systematic differences in biosynthetic fractionation between these two plant groups, which was on average -198 and-159 parts per thousand for C3 and C4 grasses, respectively. We present novel and exciting data on how leaf wax n-alkane 2H values from grasses are affected by plant physiological (leaf water evaporative 2H-enrichment) or biochemical processes (biosynthetic hydrogen isotope fractionation). These results are very interesting because they shed new light on how naturally observed differences between 2H values from C3 and C4 grasses and dicots can be explained by systematic differences in the biosynthesis of n-alkanes between these plant group (i.e. largely driven by NADPH origins).
KW  - biosynthetic fractionation
KW  - C3 and C4 grasses
KW  - deuterium
KW  - leaf water evaporative H-2-enrichment
KW  - leaf wax n-alkanes
Y1  - 2016
U6  - https://doi.org/10.1111/pce.12789
SN  - 0140-7791
SN  - 1365-3040
VL  - 39
SP  - 2390
EP  - 2403
PB  - Wiley-Blackwell
CY  - Hoboken
ER  -