Data for: Snow algae drive productivity and weathering at volcanic rock-hosted glaciers

Carbon and nitrogen isotope data, carbon uptake data, and aqueous geochemistry data from supraglacial, subglacial, and periglacial environments of stratovolcanoes in Washington and Oregon, USA. Authors: Jeff R. Havig1,* and Trinity L. Hamilton2,3 1Dept. of Earth Sciences, University of Minnesota, Minneapolis, MN, USA 55455 2Dept. of Plant and Microbial Biology, University of Minnesota, St. Paul, MN, USA 55108 3BioTechnology Institute, University of Minnesota, St. Paul, MN, USA 55108 *Corresponding Author: 116 Church Street SE, 150 Tate Hall, Minneapolis, MN 55455-0231; [e-mail]; [phone] Paper Title: Snow algae drive productivity and weathering at volcanic rock-hosted glaciers Paper Abstract: Earth has experienced periodic local to global glaciation for nearly 3 billion years, providing supra- and subglacial environments for colonization by microbial communities. A number of studies have reported on the role of microbial communities in glacial ecosystems including their influence on element cycling and weathering, but there is a paucity data on volcanic rock-hosted glacial ecosystems. Glaciers on stratovolcanoes in the Pacific Northwest override silica-rich rocks which represent analogues to an early Martian cryosphere. On these glaciers, blooms of photosynthetic snow algae support supraglacial microbial communities as has been observed on snowfields, glaciers, and ice sheets. In subglacial environments of volcanic rock-hosted glacial systems, weathering is driven, at least in part, by carbonic acid, suggesting a link between supraglacial carbon sources and subglacial heterotrophic microbial communities. Here, we report inorganic carbon assimilation and microbial community composition on glaciers across three stratovolcanoes ranging in composition from dacitic to mafic in the Pacific Northwest of the United States to begin to constrain the role of supraglacial primary productivity in subglacial weather processes. These data, coupled to contextual carbon and nitrogen isotope analyses of biomass and aqueous geochemistry, indicate snow algae drive light dependent carbon uptake across supraglacial and periglacial environments. Furthermore, snow algae microbial communities are supported by fixed nitrogen predominantly from deposition via precipitation. Our data highlight intense cycling of carbon and nitrogen driven by supraglacial microbial communities that feeds subglacial microbial communities which in turn may drive weathering processes. These results further underscore the role of glacial ecosystems in global biogeochemical cycling, especially during past global glaciations. Finally, these results lend support for glaciers as refugia for biodiversity on Earth and potentially on other bodies such as Mars where evidence exists for widespread and long-lived cryosphere including glaciers and ice sheets.美国华盛顿州和俄勒冈州层状火山（stratovolcanoes）的冰面环境（supraglacial environments）、冰下环境（subglacial environments）及冰缘环境（periglacial environments）的碳同位素（carbon isotope）数据、氮同位素（nitrogen isotope）数据、碳吸收数据以及水地球化学（aqueous geochemistry）数据。 作者：Jeff R. Havig¹,* 与 Trinity L. Hamilton²,³ ¹美国明尼苏达大学地球科学系，明尼阿波利斯，MN 55455 ²美国明尼苏达大学植物与微生物生物学系，圣保罗，MN 55108 ³美国明尼苏达大学生物技术研究所，圣保罗，MN 55108 *通讯作者：美国明尼苏达州明尼阿波利斯市东南教堂街116号泰特楼150室，55455-0231；[e-mail]；[phone] 论文标题：雪藻驱动火山岩宿主冰川的生产力与风化作用 论文摘要：地球近30亿年以来经历了多轮局地至全球性的冰期，为微生物群落定植提供了冰面与冰下环境。已有多项研究探讨了冰川生态系统中微生物群落的作用，包括其对元素循环与风化过程的影响，但针对火山岩宿主冰川生态系统的相关数据仍较为匮乏。太平洋西北地区的层状火山冰川覆盖着富硅岩石，这类岩石可作为早期火星冰冻圈（Martian cryosphere）的类比研究对象。在这些冰川上，正如在雪原、冰川与冰盖中观测到的那样，光合雪藻的水华支撑着冰面微生物群落。在火山岩宿主冰川系统的冰下环境中，风化作用至少部分由碳酸驱动，这表明冰面碳源与冰下异养微生物群落（heterotrophic microbial communities）之间存在关联。本研究针对美国太平洋西北地区三座成分从英安岩（dacitic）到基性岩（mafic）的层状火山冰川，报道了其无机碳同化（inorganic carbon assimilation）作用与微生物群落组成数据，以期限定冰面初级生产力在冰下风化过程中的作用。结合对生物量的碳、氮同位素分析与水地球化学数据，本研究结果表明，雪藻驱动了冰面及冰缘环境中依赖光照的碳吸收过程。此外，雪藻微生物群落的氮源主要来自降水沉降的固定态氮。本研究数据凸显了冰面微生物群落驱动的强烈碳氮循环，该循环可为冰下微生物群落提供养分，而冰下微生物群落又可进一步驱动风化过程。这些结果进一步强调了冰川生态系统在全球生物地球化学循环（biogeochemical cycling）中的作用，尤其是在过去的全球冰期之中。最后，本研究结果支持冰川作为地球生物多样性避难所的观点，同时也为火星等存在广泛且长期存在的冰冻圈（包括冰川与冰盖）证据的天体提供了潜在的生物多样性避难所类比依据。