Carbon stable isotopes as a palaeoclimate proxy in vascular plant dominated peatlands
Carbon stable isotopes as a palaeoclimate proxy in vascular plant dominated peatlands
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DOI：
10.1016/j.gca.2015.05.011
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发表时间：
2015
影响因子：
5
通讯作者：
M. Amesbury;D. Charman;R. Newnham;N. Loader;J. Goodrich;Jessica Royles;D. Campbell;T. Roland;A. Gallego-Sala
中科院分区：
文献类型：
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作者：
M. Amesbury;D. Charman;R. Newnham;N. Loader;J. Goodrich;Jessica Royles;D. Campbell;T. Roland;A. Gallego-Sala
碳稳定同位素（δ 13 C）记录从维管植物占主导地位的泥炭地已被用作古气候代用品，但在这些生态系统中的分馏过程需要更好的经验理解。在这里，我们测试的潜力，δ 13 C分析的雨养restiad泥炭地在新西兰，占主导地位的电线拉什（Empodismaspp.），为发展古气候记录提供一种方法。我们采集了地表植物样本，测量了地下水位深度和（微）气候在空间（6个地点跨越10°纬度）和时间（1年内每月测量）梯度上的变化，并分析了纤维素δ 13 C值与环境参数之间的关系。δ 13 C与温度、光合有效辐射和0 °C以上生长度日数呈显著负相关。δ 13 C与降水量、相对湿度、土壤含水量和地下水位深度之间没有显著的相关性，表明没有生长季水分限制，维管植物中δ 13 C与水文变量之间的预期联系脱钩。假鹰爪属（Empodismaspp.）因此，根可以在气候敏感地区提供有价值的温度替代，但需要进一步的生理和亚化石校准研究，以充分了解观察到的信号。
Carbon stable isotope (δ13C) records from vascular plant dominated peatlands have been used as a palaeoclimate proxy, but a better empirical understanding of fractionation processes in these ecosystems is required. Here, we test the potential of δ13C analysis of ombrotrophic restiad peatlands in New Zealand, dominated by the wire rush (Empodismaspp.), to provide a methodology for developing palaeoclimatic records. We took surface plant samples alongside measurements of water table depth and (micro)climate over spatial (six sites spanning > 10° latitude) and temporal (monthly measurements over 1 year) gradients and analysed the relationships between cellulose δ13C values and environmental parameters. We found strong, significant negative correlations between δ13C and temperature, photosynthetically active radiation and growing degree days above 0 °C. No significant relationships were observed between δ13C and precipitation, relative humidity, soil moisture or water table depth, suggesting no growing season water limitation and a decoupling of the expected link between δ13C in vascular plants and hydrological variables. δ13C ofEmpodismaspp. roots may therefore provide a valuable temperature proxy in a climatically sensitive region, but further physiological and sub-fossil calibration studies are required to fully understand the observed signal.