δD values of n-alkanes in Tibetan lake sediments and aquatic macrophytes - a surface sediment study and application to a 16 ka record from Lake Koucha.

Abstract A set of lake surface sediment samples and aquatic macrophytes from the eastern and central Tibetan Plateau and a sediment core from Koucha Lake (northeastern Tibetan Plateau) were analysed for hydrogen isotope signals of aliphatic lipid biomarkers. The δD values of n -alkanes were correlated with those of meteoric water in the summer months and showed increasing Pearson correlation coefficients with increasing n -alkane chain length ( r , 0.80 for n -C 31 ). While in samples from the most humid regions (southeastern Tibetan Plateau), the apparent enrichment factors between meteoric water and lipids are close to those reported for other humid sites ( e  ≈ −135‰ for mid-chain and ≈ − 125‰ for long chain n -alkanes), they become smaller ( e  ≈ −118‰ to −41‰; mean value: −86‰) at sites with a negative moisture balance (northeastern and central Tibetan Plateau and Qaidam Basin). This might be caused by enrichment in deuterium of the source water used for lipid synthesis as a result of lake water evaporation and soil and leaf water evapotranspiration. In the core from Lake Koucha, decreasing δD values of all n -alkanes between 15 and 10 cal ka BP give evidence for an intensification of the Asian summer monsoon. At ca. 9 cal ka BP, a ca. 15‰ shift towards higher δD values of mid-chain n -alkanes suggests enhanced evaporation of the lake water, which outweighs higher precipitation amounts because of a temperature increase during the early Holocene monsoonal maximum. Only a few surface sediment samples show a significant offset between δD values of mid-chain n -alkanes and n- C 31 (ΔδD mid- n -C31 ) and no systematic dependence between this offset and environmental parameters, such as mean annual precipitation, was found. In the core, available data for most samples also do not show a significant offset, only a slight increase (≈ + 15‰) of ΔδD mid- n -C31 at ca 10.0 cal ka BP and a decrease (≈ − 17‰) at ca 6.8 cal ka BP might indicate wetter and drier conditions, respectively. However, interpretation of ΔδD mid- n -C31 throughout the record is difficult because of a lack of reliable data for n- C 31 in key sections of the core. So, more records are necessary to further test the potential applicability of ΔδD mid- n -C31 as a proxy for palaeo-hydrological conditions.

[1]  G. Gleixner,et al.  Hydrogen isotope ratios of recent lacustrine sedimentary n-alkanes record modern climate variability , 2004 .

[2]  U. Herzschuh,et al.  Influence of aquatic macrophytes on the stable carbon isotopic signatures of sedimentary organic matter in lakes on the Tibetan Plateau , 2010 .

[3]  E. Mosley‐Thompson,et al.  Tropical Climate Instability: The Last Glacial Cycle from a Qinghai-Tibetan Ice Core , 1997 .

[4]  Jürgen Böhner,et al.  Land-Surface Parameters Specific to Topo-Climatology , 2009 .

[5]  W. D'Andrea,et al.  Can sedimentary leaf waxes record D/H ratios of continental precipitation? Field, model, and experimental assessments , 2008 .

[6]  T. Yao,et al.  A multi-proxy approach to reconstruct hydrological changes and Holocene climate development of Nam Co, Central Tibet , 2007 .

[7]  J. Jouzel,et al.  Evidence for general instability of past climate from a 250-kyr ice-core record , 1993, Nature.

[8]  S. Derenne,et al.  Possible algal origin of long chain odd n-alkanes in immature sediments as revealed by distributions and carbon isotope ratios , 1994 .

[9]  L. Sternberg.  D/H ratios of environmental water recorded by D/H ratios of plant lipids , 1988, Nature.

[10]  H. Naraoka,et al.  Hydrogen and carbon isotopic fractionations of lipid biosynthesis among terrestrial (C3, C4 and CAM) and aquatic plants. , 2004, Phytochemistry.

[11]  J. Clague,et al.  Late Holocene paleohydrology of Kluane Lake, Yukon Territory, Canada , 2010 .

[12]  A. Schimmelmann,et al.  D/H isotope ratios of kerogen, bitumen, oil, and water in hydrous pyrolysis of source rocks containing kerogen types I, II, IIS, and III , 1999 .

[13]  S. Feakins,et al.  Controls on the D/H ratios of plant leaf waxes in an arid ecosystem , 2010 .

[14]  U. Herzschuh,et al.  An ostracod-conductivity transfer function for Tibetan lakes , 2007 .

[15]  R. Jaffé,et al.  Origin and transport of sedimentary organic matter in two subtropical estuaries: a comparative, biomarker-based study , 2001 .

[16]  M. Pagani,et al.  δ13C and δD compositions of n-alkanes from modern angiosperms and conifers: An experimental set up in central Washington State, USA , 2008 .

[17]  U. Herzschuh,et al.  Quantitative climate and vegetation trends since the late glacial on the northeastern Tibetan Plateau deduced from Koucha Lake pollen spectra , 2009, Quaternary Research.

[18]  Jürgen Böhner,et al.  General climatic controls and topoclimatic variations in Central and High Asia , 2006 .

[19]  J. Gat.  OXYGEN AND HYDROGEN ISOTOPES IN THE HYDROLOGIC CYCLE , 1996 .

[20]  J. Overpeck,et al.  A synthesis of abrupt changes in the Asian summer monsoon since the last deglaciation , 2003 .

[21]  J. Beek,et al.  Developments in Soil Science , 2019, Global Change and Forest Soils.

[22]  A. Schwalb.  Lacustrine ostracodes as stable isotope recorders of late-glacial and Holocene environmental dynamics and climate , 2003 .

[23]  M. Kusakabe,et al.  Oxygen-18 and carbon-13 records for the last 14,000 years from Lacustrine carbonates of Siling-Co (Lake) in the Qinghai-Tibetan Plateau , 1993 .

[24]  Y. Huang,et al.  Hydrogen isotope ratios of individual lipids in lake sediments as novel tracers of climatic and environmental change: a surface sediment test , 2004 .

[25]  H. Naraoka,et al.  Carbon and hydrogen isotopic fractionation during lipid biosynthesis in a higher plant (Cryptomeria japonica). , 2004, Phytochemistry.

[26]  S. Rowland,et al.  The widespread occurrence of highly branched acyclic C20, C25 and C30 hydrocarbons in recent sediments and biota—A review , 1990 .

[27]  G. Eglinton,et al.  An n-alkane proxy for the sedimentary input of submerged/floating freshwater aquatic macrophytes , 2000 .

[28]  G. Bowen,et al.  Interpolating the isotopic composition of modern meteoric precipitation , 2003 .

[29]  T. Yao,et al.  Effect of lake evaporation on dD values of lacustrine n-alkanes: A comparison of Nam Co (Tibetan Plateau) and Holzmaar (Germany) , 2008 .

[30]  R. L. Edwards,et al.  A High-Resolution Absolute-Dated Late Pleistocene Monsoon Record from Hulu Cave, China , 2001, Science.

[31]  J. Kutzbach,et al.  Forcing of late Cenozoic northern hemisphere climate by plateau uplift in southern Asia and the American west , 1989 .

[32]  R. Schneider,et al.  Climatic controls on central African hydrology during the past 20,000 years , 2005, Nature.

[33]  J. Erzinger,et al.  Reduced early Holocene moisture availability in the Bayan Har Mountains, northeastern Tibetan Plateau, inferred from a multi-proxy lake record , 2008 .

[34]  W. D'Andrea,et al.  Hydrogen isotopic variability in leaf waxes among terrestrial and aquatic plants around Blood Pond, Massachusetts (USA) , 2007 .

[35]  G. Jia,et al.  Compound specific δD values of long chain n-alkanes derived from terrestrial higher plants are indicative of the δD of meteoric waters: evidence from surface soils in eastern China. , 2009 .

[36]  Zhaodong Feng,et al.  Dry or humid? Mid-Holocene humidity changes in arid and semi-arid China , 2006 .

[37]  F. Lehmkuhl,et al.  Basin morphology and seismic stratigraphy of Lake Donggi Cona, north-eastern Tibetan Plateau, China , 2010 .

[38]  U. Herzschuh,et al.  Biomarker and compound-specific δ13C evidence for changing environmental conditions and carbon limitation at Lake Koucha, eastern Tibetan Plateau , 2010 .

[39]  H. Naraoka,et al.  Compound-specific δD–δ13C analyses of n-alkanes extracted from terrestrial and aquatic plants , 2003 .

[40]  P. Braconnot,et al.  Evolution and variability of the Asian monsoon system: state of the art and outstanding issues. , 2005 .

[41]  Caitlin E. Buck,et al.  Intcal04 Terrestrial Radiocarbon Age Calibration, 0–26 Cal Kyr BP , 2004, Radiocarbon.

[42]  A. Schimmelmann,et al.  Fractionation of hydrogen isotopes in lipid biosynthesis , 1999 .

[43]  K. Różański,et al.  Relation Between Long-Term Trends of Oxygen-18 Isotope Composition of Precipitation and Climate , 1992, Science.

[44]  U. Herzschuh.  Reliability of pollen ratios for environmental reconstructions on the Tibetan Plateau , 2007 .

[45]  Weijian Zhou,et al.  Hydrogen isotopic ratios of plant wax n-alkanes in a peat bog deposited in northeast China during the last 16 kyr , 2009 .

[46]  H. Birks,et al.  Holocene moisture evolution in arid central Asia and its out-of-phase relationship with Asian monsoon history , 2008 .

[47]  A. Sessions.  Seasonal changes in D/H fractionation accompanying lipid biosynthesis in Spartina alterniflora , 2006 .

[48]  Hong Yang,et al.  Preservation of lipid hydrogen isotope ratios in Miocene lacustrine sediments and plant fossils at Clarkia, northern Idaho, USA , 2003 .

[49]  A. Schimmelmann,et al.  Compound-specific D/H ratios of lipid biomarkers from sediments as a proxy for environmental and climatic conditions , 2001 .

[50]  G. Gleixner,et al.  δD values of individual n-alkanes from terrestrial plants along a climatic gradient – Implications for the sedimentary biomarker record , 2006 .

[51]  K. Freeman,et al.  Influence of physiology and climate on δD of leaf wax n-alkanes from C3 and C4 grasses , 2006 .

[52]  D. Welte,et al.  Preparative hydrocarbon group type determination by automated medium pressure liquid chromatography , 1980 .

[53]  R. Edwards,et al.  Timing, Duration, and Transitions of the Last Interglacial Asian Monsoon , 2004, Science.

[54]  U. Herzschuh.  Palaeo-moisture evolution in monsoonal Central Asia during the last 50,000 years , 2006 .

[55]  C. Largeau,et al.  An n-alkatriene and some n-alkadienes from the A race of the green alga Botryococcus braunii , 1986 .

[56]  Liping Zhu,et al.  Hydrogen isotope ratios of terrigenous n-alkanes in lacustrine surface sediment of the Tibetan Plateau record the precipitation signal , 2008 .

[57]  W. Dansgaard.  Stable isotopes in precipitation , 1964 .