PDF(Pubmed)
Abstract：
The network of lava tubes is one of the most unexploited natural wonders of the Galapagos Islands. Here, we provide the first morphological, mineralogical, and biogeochemical assessment of speleothems from volcanic caves of the Galapagos to understand their structure, composition, and origin, as well as to identify organic molecules preserved in speleothems. Mineralogical analyses revealed that moonmilk and coralloid speleothems from Bellavista and Royal Palm Caves were composed of calcite, opal-A, and minor amounts of clay minerals. Extracellular polymeric substances, fossilized bacteria, silica microspheres, and cell imprints on siliceous minerals evidenced microbe-mineral interactions and biologically-mediated silica precipitation. Alternating depositional layers between siliceous and carbonate minerals and the detection of biomarkers of surface vegetation and anthropogenic stressors indicated environmental and anthropogenic changes (agriculture, human waste, and cave visits) on these unique underground resources. Stable isotope analysis and Py-GC/MS were key to robustly identify biomarkers, allowing for implementation of future protection policies.
摘要：
熔岩管网络是加拉帕戈斯群岛最未经开发的自然奇观之一。这里,我们提供了第一个形态学，矿物学,以及对加拉帕戈斯火山洞穴中的长齿茎进行生物地球化学评估，以了解它们的结构，composition,和起源,以及鉴定保存在鞘膜中的有机分子。矿物学分析表明，来自Bellavista和皇家棕榈洞的月乳和珊瑚类长骨由方解石组成，蛋白石A,和少量粘土矿物.细胞外聚合物,细菌化石,二氧化硅微球,和硅质矿物上的细胞印记证明了微生物-矿物相互作用和生物介导的二氧化硅沉淀。硅质和碳酸盐矿物之间的交替沉积层以及表面植被生物标志物和人为压力源的检测表明环境和人为变化（农业，人类排泄物,和洞穴参观)对这些独特的地下资源。稳定同位素分析和Py-GC/MS是可靠识别生物标志物的关键，允许实施未来的保护政策。
