Deciphering the atmospheric signal in marine sulfate oxygen isotope composition
Deciphering the atmospheric signal in marine sulfate oxygen isotope composition
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DOI：
10.1016/j.epsl.2019.06.013
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发表时间：
2019-09
影响因子：
5.3
通讯作者：
A. Waldeck;B. Cowie;Enric Bertran;B. Wing;I. Halevy;D. Johnston
中科院分区：
文献类型：
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作者：
A. Waldeck;B. Cowie;Enric Bertran;B. Wing;I. Halevy;D. Johnston
大气中的O2和CO2水平告诉我们化学和生物环境的变化，但大气成分的历史，特别是pO 2，没有得到很好的约束。海洋SO 4 2−的三重氧同位素（16，17，18 O）组成被认为可以直接记录同期大气中的pO 2/pCO 2比值。为了解决这个大气信号，一个精确的测量17 O组成的硫酸盐和一个模型来解释测量是必要的。在这里，我们提出了现代海洋硫酸盐的三重氧同位素组成的精确测量，然后提出了一种新的硫循环模型，去卷积潜在的大气和微生物输入到这个信号。我们的解释海洋硫酸盐氧同位素组成提供了一个框架，计算大气组成，地球化学活动的相对速率，并可以应用于海洋硫酸盐的地质记录，以限制随时间的pO 2/pCO 2比。
Atmospheric O 2 and CO 2 levels inform us of the changes in chemical and biological environments, yet the history of atmospheric compositions, and pO 2 in particular, is not well-constrained. The triple oxygen isotope (16, 17, 18 O) composition of marine SO 4 2− has been proposed to directly record the ratio pO 2/pCO 2 in the contemporaneous atmosphere. To resolve this atmospheric signal, both a precise measurement of the 17 O composition of sulfate and a model with which to interpret the measurement are needed. Here we present precise measurements of the triple oxygen isotope composition of modern marine sulfate and then forward a novel sulfur cycle model that deconvolves the potential atmospheric and microbial inputs to this signal. Our interpretation of marine sulfate oxygen isotope composition provides a framework for calculating atmospheric composition, relative rates of biogeochemical activity, and can be applied to geologic records of marine sulfate to constrain the pO 2/pCO 2 ratio over time.