美国华盛顿大学 R. N. Bryant 的课题组在研究去卷积微生物和环境对海洋沉积黄铁矿硫同位素比率的控制中取得新进展。相关论文发表在2023年11月24日出版的《科学》期刊上。

研究提出了一种对 δ ³⁴S_pyr 影响的多个信号进行去卷积的微观分析方法，产生了微生物同位素分馏(ε_mic)的明确测定和关于沉积条件的新信息。研究人员将这种方法应用于最近的冰期—间冰期沉积物，这些沉积物在这些环境转变中具有超过 70‰ 的体积的总 δ ³⁴S_pyr 变化。尽管环境发生了深度的变化，ε_mic 在次期间内基本保持不变，而 δ ³⁴S_pyr 的观测范围是由气候引起的沉积变化驱动的。

据介绍，过去环境条件和生物活动的重建，通常基于大量稳定同位素替代物，这些替代物本质上可以有多种解释。沉积黄铁矿的硫同位素组成(δ ³⁴S_pyr)尤其如此，它被用来重建海洋—大气氧化状态和跟踪几种微生物代谢途径的演变。

附：英文原文

Title: Deconvolving microbial and environmental controls on marine sedimentary pyrite sulfur isotope ratios

Author: R. N. Bryant, J. L. Houghton, C. Jones, V. Pasquier, I. Halevy, D. A. Fike

Issue&Volume: 2023-11-24

Abstract: Reconstructions of past environmental conditions and biological activity are often based on bulk stable isotope proxies, which are inherently open to multiple interpretations. This is particularly true of the sulfur isotopic composition of sedimentary pyrite (δ ³⁴S_pyr), which is used to reconstruct ocean-atmosphere oxidation state and track the evolution of several microbial metabolic pathways. We present a microanalytical approach to deconvolving the multiple signals that influence δ ³⁴S_pyr, yielding both the unambiguous determination of microbial isotopic fractionation (ε_mic) and new information about depositional conditions. We applied this approach to recent glacial-interglacial sediments, which feature over 70‰ variations in bulk δ ³⁴S_pyracross these environmental transitions. Despite profound environmental change, ε_mic remained essentially invariant throughout this interval and the observed range in δ ³⁴S_pyrwas instead driven by climate-induced variations in sedimentation.

DOI: adg6103

Source: https://www.science.org/doi/10.1126/science.adg6103