Larch Cellulose Shows Significantly Depleted Hydrogen Isotope Values With Respect to Evergreen Conifers in Contrast to Oxygen and Carbon Isotopes
Larch Cellulose Shows Significantly Depleted Hydrogen Isotope Values With Respect to Evergreen Conifers in Contrast to Oxygen and Carbon Isotopes
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DOI：
10.3389/feart.2020.523073
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发表时间：
2020-12-03
影响因子：
2.9
通讯作者：
Leuenberger, Markus
中科院分区：
文献类型：
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作者：
Arosio, Tito;Ziehmer-Wenz, Malin Michelle;Leuenberger, Markus
树轮纤维素稳定同位素分析是古气候研究的重要工具。长树轮年表主要由欧洲的橡树和针叶树组成，包括落叶松（Larix decidua）和雪松（Pinus cembra），它们在阿尔卑斯山形成了非常长的树轮年表，并生长在树线上，树木的生长主要由温度变化决定。我们分析了三角洲C-13，三角洲O-18和三角洲H-2同位素的纤维素提取树木年轮的木材样品收集在高海拔地区在瑞士和蒂罗尔阿尔卑斯山，覆盖整个全新世时期。我们发现，落叶松纤维素的氘消耗量明显高于雪松，落叶松的平均δ H-2值为-113.4 +/- 9.7 ‰，雪松为-65.4 +/- 11.3 ‰。为了验证这些耗尽的值是特定的落叶针叶树的落叶松或属性，我们扩展了分析从各种生活针叶树种收集在伯尔尼植物园的样品。结果表明，不仅落叶松，而且所有的样本的落叶落叶松家庭有一个纤维素组合物，是高度耗尽的三角洲H-2相对于其他万年青针叶树，包括cembran松，一个差异，我们归因于一个更快的代谢的落叶针叶树。的三角洲O-18值之间没有统计学差异的物种，在协议的假设，它们是主要的信号的水源水。落叶松的δ C-13值略高于雪松，这可能是由于两个物种的代谢差异。我们的结论是落叶落叶松针叶树有特定的代谢氢分馏和落叶松独特的签名三角洲H-2是有用的，以识别它从其他针叶树亚化石木材样品收集古气候研究。对于气候信息，落叶松的绝对Δ H-2值应仔细考虑，并与其他物种分开。
The analysis of the stable isotope of the tree-ring cellulose is an important tool for paleo climatic investigations. Long tree-ring chronologies consist predominantly of oaks and conifers in Europe, including larch trees (Larix decidua) and cembran pines (Pinus cembra) that form very long tree ring chronologies in the Alps and grow at the treeline, where tree growth is mainly determined by temperature variations. We analyzed delta C-13, delta O-18 and delta H-2 isotopes in the cellulose extracted from tree-rings of wood samples collected at high altitude in the Swiss and Tyrol Alps, covering the whole Holocene period. We found that larch cellulose was remarkably more depleted in deuterium than that of cembran pine, with mean delta H-2 values of -113.4 +/- 9.7 parts per thousand for larch and of -65.4 +/- 11.3 parts per thousand for cembran pine. To verify if these depleted values were specific to larch or a property of the deciduous conifers, we extended the analysis to samples from various living conifer species collected at the Bern Botanical Garden. The results showed that not only the larch, but also all the samples of the deciduous larch family had a cellulose composition that was highly depleted in delta H-2 with regard to the other evergreen conifers including cembran pine, a difference that we attribute to a faster metabolism of the deciduous conifers. The delta O-18 values were not statistically different among the species, in agreement with the hypothesis that they are primary signals of the source water. While the delta C-13 values were slightly more depleted for larch than for cembran pine, likely due to metabolic differences of the two species. We conclude that the deciduous larch conifers have specific metabolic hydrogen fractionations and that the larch unique signature of delta H-2 is useful to recognize it from other conifers in subfossil wood samples collected for paleoclimatic studies. For climate information the absolute delta H-2 values of larch should be considered carefully and separate from other species.