We used a deep-ultraviolet fluorescence mapping spectrometer, coupled to a drill system, to scan from the surface to 105 m depth into the Greenland ice sheet. The scan included firn and glacial ice and demonstrated that the instrument is able to determine small (mm) and large (cm) scale regions of organic matter concentration and discriminate spectral types of organic matter at high resolution. Both a linear point cloud scanning mode and a raster mapping mode were used to detect and localize microbial and organic matter “hotspots” embedded in the ice. Our instrument revealed diverse spectral signatures. Most hotspots were <20 mm in diameter, clearly isolated from other hotspots, and distributed stochastically; there was no evidence of layering in the ice at the fine scales examined (100 μm per pixel). The spectral signatures were consistent with organic matter fluorescence from microbes, lignins, fused-ring aromatic molecules, including polycyclic aromatic hydrocarbons, and biologically derived materials such as fulvic acids. In situ detection of organic matter hotspots in ice prevents loss of spatial information and signal dilution when compared with traditional bulk analysis of ice core meltwaters. Our methodology could be useful for detecting microbial and organic hotspots in terrestrial icy environments and on future missions to the Ocean Worlds of our Solar System.

中文翻译：

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格陵兰冰盖中微生物和多种有机物质热点的地下原位检测。

我们使用深紫外荧光测绘光谱仪，与钻孔系统耦合，从表面扫描到格陵兰冰盖 105 m 的深度。扫描包括冷杉和冰川冰，表明该仪器能够确定有机物质浓度的小 (mm) 和大 (cm) 尺度区域，并以高分辨率区分有机物质的光谱类型。线性点云扫描模式和光栅映射模式都用于检测和定位嵌入冰中的微生物和有机物质“热点”。我们的仪器揭示了不同的光谱特征。大多数热点直径<20 mm，与其他热点明显隔离，随机分布；在所检查的精细尺度（每像素 100 微米）中，没有证据表明冰层中存在分层。与传统的冰芯融水整体分析相比，原位检测冰中有机物热点可防止空间信息丢失和信号稀释。我们的方法可用于检测陆地冰冷环境中的微生物和有机热点，以及未来前往太阳系海洋世界的任务。