BRYOCARB:: A process-based model of thallose liverwort carbon isotope fractionation in response toCO2, O2, light and temperature
BRYOCARB:: A process-based model of thallose liverwort carbon isotope fractionation in response toCO2, O2, light and temperature
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DOI：
10.1016/j.gca.2006.01.031
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发表时间：
2006-12-01
影响因子：
5
通讯作者：
Beerling, David J.
中科院分区：
文献类型：
--
作者：
Fletcher, Benjamin J.;Brentnall, Stuart J.;Beerling, David J.
实验室实验的证据表明，苔藓植物(苔藓和苔藓)对碳的重稳定同位素(Delta C-13)的分馏强烈依赖于大气中的二氧化碳。因此，这种生理反应可能为开发新的陆地二氧化碳替代物提供基础[Fletcher，B.J.，Beerling，D.J.，Brentnall，S.J.，Royer，D.L.，2005。作为古代二氧化碳水平记录器的苔藓化石：实验证据和白垩纪案例研究。全球生物化学。周期19，GB3012]。在这里，我们通过建立苔藓植物碳同位素分馏的扩展模型(BRYOCARB)，建立了替代模型的理论基础，该模型集成了光合作用二氧化碳同化的生化理论和通过大气扩散控制二氧化碳供应的机制。BRYOCARB模型是通过测量地钱光合作用和Delta C-13对不同二氧化碳浓度下大气O-2、温度和光照变化的响应来进行评估的。我们发现苔藓植物的替代物对大气二氧化碳的变化至少和其他两种基于碳同位素的古二氧化碳水平估算方法(浮游植物和古土壤的C-13增量)一样敏感。BRYOCARB的数学反演提供了一种从苔藓化石碳中估算大气二氧化碳水平的机械方法，可以明确地解释过去氧气和气候差异的影响。(C)2006 Elsevier Inc.保留所有权利。
Evidence from laboratory experiments indicates that fractionation against the heavy stable isotope of carbon (Delta C-13) by bryophytes (liverworts and mosses) is strongly dependent on atmospheric CO2. This physiological response may therefore provide the basis for developing a new terrestrial CO2 proxy [Fletcher, B.J., Beerling, D.J., Brentnall, S.J., Royer, D.L., 2005. Fossil bryophytes as recorders of ancient CO2 levels: experimental evidence and a Cretaceous case study. Global Biogeochem. Cycles 19, GB3012]. Here, we establish a theoretical basis for the proxy by developing an extended model of bryophyte carbon isotope fractionation (BRYOCARB) that integrates the biochemical theory of photosynthetic CO2 assimilation with controls on CO2 supply by diffusion from the atmosphere. The BRYOCARB model is evaluated against measurements of the response of liverwort photosynthesis and Delta C-13 to variations in atmospheric O-2, temperature and irradiance at different CO2 concentrations. We show that the bryophyte proxy is at least as sensitive to variations in atmosphere CO2 as the two other leading carbon isotope-based approaches to estimating palaeo-CO2 levels (delta C-13 of phytoplankton and of paleosols). Mathematical inversion of BRYOCARB provides a mechanistic means of estimating atmospheric CO2 levels from fossil bryophyte carbon that can explicitly account for the effects of past differences in O-2 and climate. (c) 2006 Elsevier Inc. All rights reserved.