Carbon isotope exchange between gaseous CO 2 and thin solution films: Artificial cave experiments and a complete diffusion-reaction model
Carbon isotope exchange between gaseous CO 2 and thin solution films: Artificial cave experiments and a complete diffusion-reaction model
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气态CO 2 和溶液薄膜之间的碳同位素交换：人工洞穴实验和完整的扩散反应模型
DOI：
10.1016/j.gca.2017.05.005
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发表时间：
2017
影响因子：
5
通讯作者：
Spötl
中科院分区：
文献类型：
--
作者：
Hansen;Scholz;Froeschmann;Schöne;Spötl
洞穴动物稳定碳同位素(δ13C)记录提供了重要的古气候和古环境信息。然而，根据过去的气候或环境变化来解释这些记录仍然具有挑战性，因为影响δ13C信号的过程多种多样。洞穴大气中的气态CO2与溶液膜中溶解的无机碳(DIC)之间的碳同位素交换是迄今为止仅有的一个较少讨论的过程，这对于通风较强的洞穴来说可能特别重要。该模型考虑了影响碳同位素交换的所有参数，如膜内、膜外和膜内的扩散，膜内发生的化学反应，以及扩散和反应速率与同位素质量和温度的关系。为了验证模型，我们在三个不同的温度(10，20，30摄氏度)下，在完全受控的洞穴模拟条件下进行了实验室实验。我们将四种不同浓度(分别为1，2，5和10≈/L)的NaHCO3溶液的薄膜(CO20.1 mm)暴露在含有特定数量的二氧化碳(1000和3000mmolPmv)的氮气气氛中。实验观察到的pH和δ~(13)C值随时间的变化与模型预测结果吻合较好。在我们的实验中，S的碳同位素交换次数从大约200次到大约16,000次不等，并且强烈地依赖于温度、薄膜厚度、大气中的二氧化碳和DIC的浓度。对于低二氧化碳(在500ppmv到1000ppmv之间，例如对于通风强烈的洞穴)，我们的时间常数大大低于之前的研究得出的时间常数，这表明碳同位素交换对洞穴δ13C值可能有更强的影响。然而，只有在滴水间隔很长和降雨率很慢的情况下，这一过程才会产生影响。
Speleothem stable carbon isotope (δ13C) records provide important paleoclimate and paleo-environmental information. However, the interpretation of these records in terms of past climate or environmental change remains challenging because of various processes affecting the δ13C signals. A process that has only been sparsely discussed so far is carbon isotope exchange between the gaseous CO2of the cave atmosphere and the dissolved inorganic carbon (DIC) contained in the thin solution film on the speleothem, which may be particularly important for strongly ventilated caves.Here we present a novel, complete reaction diffusion model describing carbon isotope exchange between gaseous CO2and the DIC in thin solution films. The model considers all parameters affecting carbon isotope exchange, such as diffusion into, out of and within the film, the chemical reactions occurring within the film as well as the dependence of diffusion and the reaction rates on isotopic mass and temperature. To verify the model, we conducted laboratory experiments under completely controlled, cave-analogue conditions at three different temperatures (10, 20, 30 °C). We exposed thin (≈0.1 mm) films of a NaHCO3solution with four different concentrations (1, 2, 5 and 10 mmol/l, respectively) to a nitrogen atmosphere containing a specific amount of CO2(1000 and 3000 ppmV). The experimentally observed temporal evolution of the pH and δ13C values of the DIC is in good agreement with the model predictions. The carbon isotope exchange times in our experiments range from ca. 200 to ca. 16,000 s and strongly depend on temperature, film thickness, atmospheric pCO2and the concentration of DIC. For low pCO2(between 500 and 1000 ppmV, as for strongly ventilated caves), our time constants are substantially lower than those derived in a previous study, suggesting a potentially stronger influence of carbon isotope exchange on speleothem δ13C values. However, this process should only have an influence in case of very long drip intervals and slow precipitation rates.
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影响因子：
4
作者：
Corinne I. Wong;J. Banner;M. Musgrove
通讯作者：
Corinne I. Wong;J. Banner;M. Musgrove
监测 Père Noël 洞穴（比利时）的气候、水文和地球化学参数：对解释洞穴同位素和地球化学时间序列的意义
DOI：
--
发表时间：
2008
期刊：
影响因子：
--
作者：
S. Verheyden;D. Genty;Guy Deflandre;Y. Quinif;E. Keppens
通讯作者：
E. Keppens
影响因子：
4.3
作者：
A. Wackerbarth;P. Langebroek;M. Werner;Gerrit Lohmann;S. Riechelmann;A. Borsato;A. Mangini
通讯作者：
A. Wackerbarth;P. Langebroek;M. Werner;Gerrit Lohmann;S. Riechelmann;A. Borsato;A. Mangini
影响因子：
5
作者：
Muehlinghuas, Christian;Scholz, Denis;Mangini, Augusto
通讯作者：
Mangini, Augusto
DOI：
10.1144/sp336.17
发表时间：
2010-01-01
期刊：
TUFAS AND SPELEOTHEMS: UNRAVELLING THE MICROBIAL AND PHYSICAL CONTROLS
影响因子：
--
作者：
Mattey, David P.;Fairchild, Ian J.;Durell, Richard
通讯作者：
Durell, Richard