Collaborative Research: Cyanobacteria, Nitrogen Cycling, and Export Production in the Laurentian Great Lakes

合作研究：劳伦森五大湖的蓝藻、氮循环和出口生产

• 批准号: 1948058
• 负责人: Trinity Hamilton
• 金额: $ 17.82万
• 依托单位: University of Minnesota-Twin Cities
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-03-15 至 2025-02-28
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1948058&HistoricalAwards=false
• 关键词: Collaborative; Research; Cyanobacteria; Nitrogen; Cycling

Collaborative Research: Cyanobacteria, Nitrogen Cycling, and Export Production in the Laurentian Great LakesThe Great Lakes hold about 20% of the freshwater on Earth and have been increasingly impacted by human activities in recent decades. Lake Erie suffers from large, annually recurring, toxic cyanobacterial blooms in summer, whereas Lake Superior experiences smaller, localized cyanobacterial blooms after storm events. Cyanobacterial blooms have harmful ecological, human health, and economic implications. These blooms are a global phenomenon, observed in lakes and oceans, and can lead to low oxygen conditions and the production of toxins, both of which can be harmful for ecosystems. Understanding how different types of cyanobacteria influence nutrient cycling remains a major knowledge gap. This project aims to provide a deeper understanding of the long-term state of the Great Lakes ecosystem. The research approach combines new and established methods. Project results and implications will be shared with local and regional water interests in partnership with the Pittsburgh Collaboratory for Water Research, Education, and Outreach, the Great Lakes Commission Harmful Algal Blooms Collaborative, and the Lake Erie Area Research Network. Education is a central part of this project and training opportunities target next generation of scientists, including postdoctoral, graduate, and undergraduate students. The students and postdoc will receive state-of-the-art training in the rapidly developing fields of biogeochemistry and geomicrobiology, while working with an interdisciplinary team of scientists.This study will examine nitrogen cycling, phytoplankton community composition, and the nitrogen isotopic composition of chloropigments in order to evaluate cyanobacterial productivity in the modern Laurentian Great Lakes as well as the historical record of cyanobacterial blooms over the past several hundred years. The nitrogen isotope composition of chloropigments is expected to provide a powerful new proxy for understanding primary productivity and the relative importance of cyanobacteria to export production and nitrogen cycling. This proxy would be valuable not only for management of modern systems but has important implications for increasing our understanding of the role of cyanobacteria throughout Earth history. This project would test this molecular isotopic proxy in contemporary aquatic ecosystems to assess its efficacy for: (1) determining the relative contributions of cyanobacteria vs eukaryotic algae (e.g., diatoms) to primary production; (2) evaluating export production of cyanobacterial productivity (including blooms); and (3) constraining historical cyanobacteria productivity in the sedimentary record. Comparison of a system characterized by eutrophication and seasonal cyanobacterial blooms (Lake Erie) with one characterized by picocyanobacteria productivity, but the near-absence of large-scale cyanobacterial blooms (Lake Superior), will provide information about the range of impacts that cyanobacteria can have on carbon and nitrogen cycling. Further information regarding nitrogen cycling will be derived from analysis of solid and dissolved nitrogen species throughout the annual cycle, as well as seasonal studies of sediment processes to measure associated sediment nitrogen removal rates through different processes.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

合作研究：劳伦森五大湖的蓝藻、氮循环和出口生产五大湖蕴藏着地球上约 20% 的淡水，近几十年来受到人类活动的影响越来越大。夏季，伊利湖每年都会出现大规模的有毒蓝藻水华，而苏必利尔湖在风暴事件后会出现规模较小的局部蓝藻水华。蓝藻水华会对生态、人类健康和经济产生有害影响。这些水华是一种全球现象，在湖泊和海洋中观察到，可能导致低氧条件和毒素的产生，这两者都可能对生态系统有害。了解不同类型的蓝藻如何影响营养循环仍然是一个主要的知识空白。该项目旨在更深入地了解五大湖生态系统的长期状态。该研究方法结合了新方法和既定方法。项目结果和影响将与匹兹堡水研究、教育和外展合作实验室、五大湖委员会有害藻华合作组织和伊利湖地区研究网络合作，与当地和区域水利益相关者分享。教育是该项目的核心部分，培训机会针对下一代科学家，包括博士后、研究生和本科生。学生和博士后将在快速发展的生物地球化学和地球微生物学领域接受最先进的培训，同时与跨学科的科学家团队合作。这项研究将检查氮循环、浮游植物群落组成和氮同位素组成。氯化色素，以评估现代劳伦森五大湖的蓝藻生产力以及过去数百年蓝藻水华的历史记录。氯色素的氮同位素组成有望为了解初级生产力以及蓝藻对出口生产和氮循环的相对重要性提供一个强大的新代理。该代理不仅对于现代系统的管理有价值，而且对于增进我们对蓝藻在整个地球历史中的作用的理解具有重要意义。该项目将在当代水生生态系统中测试这种分子同位素代理，以评估其功效：（1）确定蓝藻与真核藻类（例如硅藻）对初级生产的相对贡献； （2）评估出口蓝藻生产力（包括水华）； (3)限制沉积记录中历史上蓝藻的生产力。将富营养化和季节性蓝藻水华（伊利湖）特征的系统与以微微蓝藻生产力为特征但几乎不存在大规模蓝藻水华（苏必利尔湖）的系统进行比较，将提供有关蓝藻可能产生的影响范围的信息关于碳和氮循环。有关氮循环的更多信息将来自对整个年度循环中的固体和溶解氮物种的分析，以及沉积物过程的季节性研究，以通过不同的过程测量相关的沉积物氮去除率。该奖项反映了 NSF 的法定使命，并被视为值得通过使用基金会的智力优点和更广泛的影响审查标准进行评估来支持。

项目成果

Diversity and distribution of sediment bacteria across an ecological and trophic gradient

• DOI: 10.1101/2021.09.20.461123
• 发表时间: 2021-09-20
• 期刊: PLoS ONE
• 影响因子: 3.7
• 作者: Hailey M. Sauer;T. Hamilton;Rika E. Anderson;C. Umbanhowar;Adam J. Heathcote
• 通讯作者: Adam J. Heathcote