当前位置： SCI文献检索 > OECOLOGIA期刊下所有文献 > Carbon and hydrogen isotope fractionation under continuous light: implications for paleoenvironmental interpretations of the High Arctic during Paleogene warming.

Carbon and hydrogen isotope fractionation under continuous light: implications for paleoenvironmental interpretations of the High Arctic during Paleogene warming.

Abstract：

:The effect of low intensity continuous light, e.g., in the High Arctic summer, on plant carbon and hydrogen isotope fractionations is unknown. We conducted greenhouse experiments to test the impact of light quantity and duration on both carbon and hydrogen isotope compositions of three deciduous conifers whose fossil counterparts were components of Paleogene Arctic floras: Metasequoia glyptostroboides, Taxodium distichum, and Larix laricina. We found that plant leaf bulk carbon isotopic values of the examined species were 1.75-4.63 per thousand more negative under continuous light (CL) than under diurnal light (DL). Hydrogen isotope values of leaf n-alkanes under continuous light conditions revealed a D-enriched hydrogen isotope composition of up to 40 per thousand higher than in diurnal light conditions. The isotope offsets between the two light regimes is explained by a higher ratio of intercellular to atmospheric CO(2) concentration (C (i)/C (a)) and more water loss for plants under continuous light conditions during a 24-h transpiration cycle. Apparent hydrogen isotope fractionations between source water and individual lipids (epsilon(lipid-water)) range from -62 per thousand (Metasequoia C(27) and C(29)) to -87 per thousand (Larix C(29)) in leaves under continuous light. We applied these hydrogen fractionation factors to hydrogen isotope compositions of in situ n-alkanes from well-preserved Paleogene deciduous conifer fossils from the Arctic region to estimate the deltaD value in ancient precipitation. Precipitation in the summer growing season yielded a deltaD of -186 per thousand for late Paleocene, -157 per thousand for early middle Eocene, and -182 per thousand for late middle Eocene. We propose that high-latitude summer precipitation in this region was supplemented by moisture derived from regionally recycled transpiration of the polar forests that grew during the Paleogene warming.

journal_name

Oecologia

journal_title

Oecologia

authors

Yang H,Pagani M,Briggs DE,Equiza MA,Jagels R,Leng Q,Lepage BA

doi

10.1007/s00442-009-1321-1

subject

Has Abstract

pub_date

2009-06-01 00:00:00

pages

461-70

issue

eissn

0029-8549

issn

1432-1939

journal_volume

160

pub_type

杂志文章

在线工具

Carbon and hydrogen isotope fractionation under continuous light: implications for paleoenvironmental interpretations of the High Arctic during Paleogene warming.