Niche differentiation between Ammonia-oxidizing Archaea and Bacteria in Freshwater lakes

氮循环是地球上最重要的营养循环之一。硝化作用，即铵到硝酸盐的生物转化，发生在几乎所有环境中，包括土壤、沉积物、淡水和海洋沃茨以及废水，并且可以导致严重的环境问题，例如促进藻类大量繁殖以及随后在水生系统中产生死区。 本研究项目涉及硝化反应的第一步和限速步骤，即氨氧化为亚硝酸盐。 氨氧化细菌已经被研究了100多年，直到最近，科学家们还认为它们是环境中唯一负责氨氧化的微生物。然而，最近发现了氨氧化为亚硝酸盐的新参与者，即氨氧化古菌。 这两个群体使用相同的资源，因为它们的基本能量产生代谢相似，并且在各种各样的环境中一起发现。 该项目将解决在不同生境中哪组氨氧化微生物负责氨氧化的问题。 该项目的重点是在阿克顿湖，在俄亥俄州的淡水湖的开放水域和底部沉积物栖息地，并将测试这两组铵氧化微生物显示生态位分化的假设。 实验工作将集中在培养依赖的方法，以调查氨氧化微生物在实验室控制条件下对环境因素的反应。 此外，一种新的培养物移植实验将用于将藻类和细菌的反应与湖中的自然条件联系起来。该项目将通过两名早期职业科学家的合作，更广泛地促进加强微生物生态学的跨学科研究。 研究生和本科生将积极参与该项目的研究，并参与基因组注释项目。 此外，将在迈阿密大学开设为期一周的课程，向K-12教师提供水质教育，重点是废水处理和水净化。

The nitrogen cycle is one of the most important nutrient cycles on the planet. Nitrification, the biological conversion of ammonium to nitrate, occurs in almost all environments, including soils, sediments, fresh and marine waters and wastewater, and can cause serious environmental problems such as promotion of algal blooms and subsequent creation of dead zones in aquatic systems. This research project concerns the first and rate limiting step of nitrification, the oxidation of ammonia to nitrite. Ammonia-oxidizing bacteria have been studied for over 100 years, and until recently scientists assumed that they were the sole microbes responsible for ammonia oxidation in the environment. However, a new player in the oxidation of ammonia to nitrite was discovered very recently, the ammonia-oxidizing Archaea. Both groups use the same resources due to the similarity in their basic energy generating metabolism, and are found in a wide variety of environments together. This project will address the question of which group of ammonia-oxidizing microbes is responsible for ammonia oxidation in different habitats. The project focuses on open water and bottom sediment habitats in Lake Acton, a freshwater lake in Ohio, and will test the hypothesis that these two groups of ammonium oxidizing microbes display niche differentiation. The experimental efforts will focus on cultivation dependent approaches to investigate the response of ammonia-oxidizing microbes to environmental factors under controlled conditions in the laboratory. In addition, a novel culture transplant experiment will be used to link the response of the Archaea and bacteria to natural conditions in the lake. This project will contribute more broadly to strengthen interdisciplinary research in microbial ecology through the collaboration of two early career scientists. Graduate and undergraduate students will be engaged in active research on the project and participate in a genome annotation project. In addition, a one-week class will be developed and offered at Miami University to educate K-12 teachers about water quality with a focus on wastewater treatment and water purification.