RUI: Collaborative Research: MIP : Lake Huron Sinkholes - Microbial Composition and Processes in Biogeochemical Hotspots

微生物在决定我们生活质量的生态系统过程中发挥着至关重要的作用。 尽管它们对人类健康和福利很重要，但地下环境中的微生物物种及其活动在很大程度上是未知的。 这个为期2年的项目将描述居住在休伦湖雷霆湾国家海洋保护区（NMS）新发现的地下水供应的湖底生态系统（淹没天坑）的微生物群落。 由于水化学差异造成的陡峭的环境梯度，天坑生境的特点是高微生物生物量和强烈的生物活动。 这些下沉的天坑似乎是生物地球化学的“热点”，类似于海洋喷口生态系统的淡水，为发现新的微生物和群落过程提供了机会。 为了更好地了解社区功能，将描述地下水排入湖底所产生的物理和化学环境，这三个天坑社区沿着深度梯度分布：浅（5米处的Misery Bay天坑）、中（18米处的中岛天坑）和深（93米处的孤立天坑）。 将使用针对不同标记的分子技术来表征微生物群落。 首先，膜脂质分析将结合测量稳定的碳同位素掺入到个别脂肪酸，提供一个综合的社区组成和活动的看法。 第二，遗传多样性概况和DNA序列数据将提供关于群落组成的高分辨率视图。 第三，荧光显微镜和放射性同位素示踪剂将用于直接评估微生物丰度和生长速率。 结合这些分析，将提供第一个详细的图片微生物的生活和过程中淹没沉孔生态系统的劳伦特五大湖。这项研究启动了一个新的研究线连接土地和水资源的五大湖。 它还描述了新的生物和独特的栖息地，招募和培训代表性不足的学生，在两个主要的本科院校的大学研究人员之间建立了强有力的合作（大峡谷州立大学和威斯康星大学斯托特分校），将研究和教育融入这两个机构的课程，与现有的推广计划合作培训K-12教育工作者，并通过将新创建的休伦湖天坑网站与NOAA的五大湖环境研究实验室和NSF的北温带湖泊微生物观测站的现有数据网络连接起来，建立数据共享基础设施。 我们的研究结果将为继续保护雷霆湾国家海洋保护区提供额外的理由，这是唯一位于淡水生态系统中的NMS。 最终，这些研究将提供对生物圈中微生物生命的更好理解，这是确保经济和环境可持续未来的关键一步。

Microorganisms play vital roles in the ecosystem processes that determine our quality of life. Despite their importance to human health and welfare, the microbial species and their activities in subsurface environments are largely unknown. This 2-year project will describe the microbial communities inhabiting newly discovered groundwater-supplied lake floor ecosystems (submerged sinkholes) in the Thunder Bay National Marine Sanctuary (NMS), Lake Huron. Due to the steep environmental gradients created by differences in water chemistry, sinkhole habitats are characterized by high microbial biomass and intense biological activity. These submerged sinkholes appear to be biogeochemical "hot spots" freshwater analogs to marine vent ecosystems that offer opportunities for discovering novel microorganisms and community processes. To better understand community function, the physical and chemical environments created by groundwater discharge into the lake floor will be characterized for three sinkhole communities located along a depth gradient; shallow (Misery Bay Sinkholes at 5 m), intermediate (Middle Island Sinkhole at 18 m) and deep (Isolated Sinkhole at 93 m). Microbial communities will be characterized using molecular techniques that target different markers. First, membrane lipid profiling will be combined with measurements of stable carbon isotope incorporation into individual fatty acids to provide an integrated view of community composition and activity. Second, genetic diversity profiles and DNA sequence data will provide a high-resolution view of community composition. Third, fluorescence microscopy and radioisotopic tracers will be used to directly assess microbial abundance and growth rates. Combined, these analyses will provide the first detailed picture of microbial life and processes in the submerged sinkhole ecosystems of the Laurentian Great Lakes.This study initiates a new line of research linking land and water resources in the Great Lakes. It also describes novel organisms and unique habitats, recruits and trains underrepresented students, forges a strong collaboration between university researchers at two predominantly undergraduate institutions (Grand Valley StateUniversity and University of Wisconsin-Stout), integrates research and education into the curriculum at both institutions, trains K-12 educators in partnership with existing outreach programs, and builds data sharing infrastructure by linking a newly created Lake Huron sinkholes website to existing data networks at NOAA's Great Lakes Environmental Research Laboratory and NSF's North Temperate Lakes Microbial Observatory. Our findings will provide additional rationale for the continued protection of Thunder Bay National Marine Sanctuary, the only NMS located in a freshwater ecosystem. Ultimately, these studies will provide a better understanding of microbial life in the biosphere, a critical step in ensuring an economically and environmentally sustainable future.