Most soils around the world are nitrogen limited and nitrogen fertiliser has to be added to the farmers’ fields to increase their crop yields. The problem with this is that up to 70% of nitrogen fertiliser is lost through the activity of ammonia oxidising archaea and bacteria and this has a negative effect on agriculture and contributes to climate change through the release of the greenhouse gas nitrous oxide. We study these ammonia oxidising microbes, which are among the most numerous living organisms on Earth and are found in diverse habitats such as soils, lakes, seas, manmade environments and even the human skin. In order to manage and balance nitrogen cycling in the environment, fundamental knowledge is required on the identity and function of the key microbes responsible. Read more about our work on this under the specific projects: