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Polar ice core organic matter signatures reveal past atmospheric carbon composition and spatial trends across ancient and modern timescales
Journal of Glaciology ( IF 3.4 ) Pub Date : 2021-05-28 , DOI: 10.1017/jog.2021.51
Juliana D'Andrilli , Joseph R. McConnell

We present polar ice core organic matter (OM) fluorescence signatures to reconstruct ancient and modern atmospheric compositions and relate OM signals to past ecological changes. OM composition from three Arctic ice cores (Canada and Greenland) was characterized by fluorescence spectroscopy and compared to an Antarctic OM record. Diverse OM was measured in ancient and modern ice in both hemispheres and similarities existed across vast spatiotemporal scales. We determined three OM markers, indicating paleoclimate and modern carbon trends: (i) ‘humic-like’, detected in Holocene ice of more complex and aromatic character, supporting trends of higher plant influences in warmer climates, (ii) monolignol- and non-amino acid-like, describing simple, lignin-like OM precursors ubiquitous in the environment and the microbial degradation products of more complex materials from plants/soils, and (iii) amino acid- and tannin-like, indicating microbial degradation of simple OM chemical species, compared to the other markers. Concentration trends were inferred from fluorescence intensities of individual OM types and related to warmer temperatures. No indicators of freshly produced OM by microbes were detected; signals were interpreted as materials externally produced from the ice and transported to polar regions. This marks the first global comparison of atmospheric reconstructions from OM across vast spatiotemporal scales.

中文翻译:

极地冰芯有机物特征揭示了古代和现代时间尺度上过去的大气碳成分和空间趋势

我们提出了极地冰芯有机物 (OM) 荧光特征来重建古代和现代大气成分,并将 OM 信号与过去的生态变化联系起来。来自三个北极冰芯(加拿大和格陵兰)的 OM 组成通过荧光光谱进行了表征,并与南极 OM 记录进行了比较。在两个半球的古代和现代冰中测量了不同的 OM,并且在广阔的时空尺度上存在相似性。我们确定了三个 OM 标记,表明古气候和现代碳趋势:(i)“腐殖质”,在更复杂和芳香特征的全新世冰中检测到,支持在温暖气候中更高植物影响的趋势,(ii)单木酚和非木酚-氨基酸样,描述简单,与其他标志物相比,环境中普遍存在的类木质素 OM 前体和更复杂的植物/土壤材料的微生物降解产物,以及 (iii) 类氨基酸和单宁,表明简单 OM 化学物种的微生物降解。从单个 OM 类型的荧光强度推断出浓度趋势,并与温度升高有关。未检测到微生物产生的新鲜有机质指标;信号被解释为从冰外部产生并运输到极地地区的物质。这标志着 OM 在广阔的时空尺度上对大气重建的首次全球比较。从单个 OM 类型的荧光强度推断出浓度趋势,并与温度升高有关。未检测到微生物产生的新鲜有机质指标;信号被解释为从冰外部产生并运输到极地地区的物质。这标志着 OM 在广阔的时空尺度上对大气重建的首次全球比较。从单个 OM 类型的荧光强度推断出浓度趋势,并与温度升高有关。未检测到微生物产生的新鲜有机质指标;信号被解释为从冰外部产生并运输到极地地区的物质。这标志着 OM 在广阔的时空尺度上对大气重建的首次全球比较。
更新日期:2021-05-28
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