Archaeal nitrification in Lake Constance, Germany

The aim of this work was to study freshwater Nitrososphaeria and their impact on the nitrogen cycling in lakes. We followed their absolute abundance in oligotrophic Lake Constance (Germany) with quantitative polymerase chain reaction (qPCR) over a time frame of two consecutive years from November 2017 until November 2019. During this time we took water samples monthly (2017/2018) or as required (2019) at a depth of 85 m. We combined this data with measurements of nitrate and ammonia concentrations in the whole water column. In addition, we performed stable isotope experiments with addition of 15N-ammonium in 2019 to analyze nitrification rate in the hypolimnion of Lake Constance. The bundled publication also includes measurements of chlorophyll a concentrations in the upper water column and measurements of temperature and oxygen in the whole water column.

本研究旨在探究淡水亚硝化球菌纲（Nitrososphaeria）及其对湖泊氮循环的影响。我们采用定量聚合酶链式反应（qPCR）技术，对德国贫营养型康斯坦茨湖中的该类群绝对丰度进行了连续两年（2017年11月至2019年11月）的监测。在此期间，我们于85米深度每月采集水样（2017/2018年）或按需采集（2019年）。我们将该数据与整个水柱中硝酸盐和氨浓度的测量结果相结合。此外，我们于2019年开展了添加15N标记铵的稳定同位素实验，以分析康斯坦茨湖湖下层的硝化速率。相关出版物中还包含上层水柱中叶绿素a浓度的测量数据，以及整个水柱中温度和氧气的测量数据。