Abstract
The effect of plant type on n-alkane biomarker has been widely studied,but the influence of plant type on n-alkanoic acids(n-FAs)has received less attention.Understanding the effect of the distribution of n-FAs and their hydrogen isotope composition(δ2HFA)is critical for interpreting sedimentary δ2HFA values as proxies of hydroclimate and/or vegetation changes.In this study,we systematically investigated the distribution ofn-FAs and δ2HFA values across seasons on the Chinese Loess Plateau(CLP).Our results showed that there were no significant seasonal differences in n-FAs distribution and δ2HFA values,but there were significant differences in a2HFA values across plant types.The δ2HFA values ranged from-185‰ to-125‰ in dicots(-161％o±28‰),and from-215％o to-170％o in monocots(-196‰±22‰)on the CLP.Isotope fractionation between δ2HFA values and precipitation δ2H(eFA-P)was also 2H-enriched in dicots relative to monocots.At the regional scale of the CLP,δ2HFA values were not correlated with δ2H values of precipitation.However,δ2HFA values from the CLP were similar to expectations from a global comparison,both in terms of their mean values and high variability among plants growing in sites with similar δ2H values of precipitation.As some of this variability in εFA-P is due to the effect of plant type,a careful assessment of the likely sources of waxes in terrestrial sediments is critical when using δ2HFA values for paleohydroclimate reconstruction.
基金项目
Chinese Academy of Sciences(ZDBS-LY-DQC033 &XDB40000000)
National Natural Science Foundation of China(42073017 & 42030512)
维普
万方数据