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 th...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(δ^(2)H_(FA))is critical for interpreting sedimentaryδ^(2)H_(FA)values as proxies of hydroclimate and/or vegetation changes.In this study,we systematically investigated the distribution ofn-FAs andδ^(2)H_(FA)values across seasons on the Chinese Loess Plateau(CLP).Our results showed that there were no significant seasonal differences in n-FAs distribution andδ^(2)H_(FA)values,but there were significant differences inδ^(2)H_(FA)values across plant types.Theδ^(2)H_(FA)values ranged from-185‰to-125‰in dicots(-161‰±28‰),and from-215‰to-170‰in monocots(-196‰±22‰)on the CLP.Isotope fractionation betweenδ^(2)H_(FA)values and precipitationδ^(2)H(ε_(FA-P))was also^(2)H-enriched in dicots relative to monocots.At the regional scale of the CLP,δ^(2)H_(FA)values were not correlated withδ^(2)H values of precipitation.However,δ^(2)H_(FA)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 similarδ^(2)H values of precipitation.As some of this variability inεFA-Pis due to the effect of plant type,a careful assessment of the likely sources of waxes in terrestrial sediments is critical when usingδ^(2)H_(FA)values for paleohydroclimate reconstruction.展开更多
基金supported by the Chinese Academy of Sciences(Grant Nos.ZDBS-LY-DQC033&XDB40000000)the National Natural Science Foundation of China(Grant Nos.42073017&42030512)。
文摘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(δ^(2)H_(FA))is critical for interpreting sedimentaryδ^(2)H_(FA)values as proxies of hydroclimate and/or vegetation changes.In this study,we systematically investigated the distribution ofn-FAs andδ^(2)H_(FA)values across seasons on the Chinese Loess Plateau(CLP).Our results showed that there were no significant seasonal differences in n-FAs distribution andδ^(2)H_(FA)values,but there were significant differences inδ^(2)H_(FA)values across plant types.Theδ^(2)H_(FA)values ranged from-185‰to-125‰in dicots(-161‰±28‰),and from-215‰to-170‰in monocots(-196‰±22‰)on the CLP.Isotope fractionation betweenδ^(2)H_(FA)values and precipitationδ^(2)H(ε_(FA-P))was also^(2)H-enriched in dicots relative to monocots.At the regional scale of the CLP,δ^(2)H_(FA)values were not correlated withδ^(2)H values of precipitation.However,δ^(2)H_(FA)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 similarδ^(2)H values of precipitation.As some of this variability inεFA-Pis due to the effect of plant type,a careful assessment of the likely sources of waxes in terrestrial sediments is critical when usingδ^(2)H_(FA)values for paleohydroclimate reconstruction.
