The majority of geomicrobiological research conducted on glacial systems to date has focused on glaciers that override primarily carbonate or granitic bedrock types, with little known of the processes that support microbial life in glacial systems overriding volcanic terrains (e.g., basalt or andesite). To better constrain the role of the supraglacial ecosystems in the carbon and nitrogen cycles, to gain insight into microbiome composition and function in alpine glacial systems overriding volcanic terrains, and to constrain potential elemental sequestration or release through weathering processes associated with snow algae communities, we examined the microbial community structure and primary productivity of snow algae communities on stratovolcanoes in the Cascade Range of the Pacific Northwest. Here, we present the first published values for carbon fixation rates of snow algae communities on glaciers in the Pacific Northwest. We observed varying levels of light‐dependent carbon fixation on supraglacial and periglacial snowfields at Mt. Hood, Mt. Adams, and North Sister. Recovery of abundant 18S rRNA transcripts affiliated with photoautotrophs and 16S rRNA transcripts affiliated with heterotrophic bacteria is consistent with previous studies indicating the majority of primary productivity on snow and ice can be attributed to photoautotrophs. In contrast to previous observations of glacial ecosystems, our geochemical, isotopic, and microcosm data suggest these assemblages are not limited by phosphorus or fixed nitrogen availability. Furthermore, our data indicate these snow algae communities actively sequester Fe, Mn, and P leached from minerals sourced from the local rocks. Our observations of light‐dependent primary productivity on snow are consistent with similar studies in polar ecosystems; however, our data may suggest that DIC may be a limiting nutrient in contrast to phosphorus or fixed nitrogen as has been observed in other glacial ecosystems. Our data underscore the need for similar studies on glacier surfaces and seasonal snowfields to better constrain the role of local bedrock and nutrient delivery on carbon fixation and biogeochemical cycling in these ecosystems.

中文翻译：

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西北太平洋平流火山上雪藻群落的初级生产力。

迄今为止，对冰川系统进行的大多数地球微生物学研究都集中在主要覆盖碳酸盐或花岗岩基岩类型的冰川上，鲜有支持冰川系统中微生物生命覆盖火山地形（例如玄武岩或安山岩）的过程。为了更好地限制超冰川生态系统在碳和氮循环中的作用，深入了解覆盖火山地形的高山冰川系统中的微生物组组成和功能，并通过与雪藻群落相关的风化过程来限制潜在的元素固存或释放，我们考察了西北太平洋喀斯喀特山脉平流火山上雪藻群落的微生物群落结构和初级生产力。这里，我们提出了西北太平洋冰川中雪藻群落的固碳率的首次公开值。我们在山上的冰缘和冰缘雪原上观察到了不同程度的依赖光的碳固定。胡德山 亚当斯和北姐妹。与自养生物相关的丰富的18S rRNA转录物和与异养细菌相关的16S rRNA转录物的回收与以前的研究一致，表明大部分雪和冰上的初级生产力可归因于自养生物。与先前对冰川生态系统的观察结果相反，我们的地球化学，同位素和微观数据表明，这些组合不受磷或固定氮可用性的限制。此外，我们的数据表明，这些雪藻群落积极隔离了Fe，Mn，和P从当地岩石中提取的矿物质中浸出。我们对雪上光依赖的初级生产力的观察结果与极地生态系统中的类似研究一致。但是，我们的数据可能表明，与其他冰川生态系统中观察到的磷或固定氮相比，DIC可能是一种限制性养分。我们的数据强调需要对冰川表面和季节性雪原进行类似的研究，以更好地限制当地基岩和营养物在这些生态系统中的固碳和生物地球化学循环中的作用。我们的数据可能表明，与其他冰川生态系统中观察到的磷或固氮相比，DIC可能是一种限制性养分。我们的数据强调需要对冰川表面和季节性雪原进行类似的研究，以更好地限制当地基岩和营养物在这些生态系统中的固碳和生物地球化学循环中的作用。我们的数据可能表明，与其他冰川生态系统中观察到的磷或固氮相比，DIC可能是一种限制性养分。我们的数据强调需要对冰川表面和季节性雪原进行类似的研究，以更好地限制当地基岩和营养物在这些生态系统中的固碳和生物地球化学循环中的作用。