“…In the autumn Musings we start with the regular highlights of our Microbe Profiles and contained within these three issues we have four to feast your microbiological eyes on. The first continues a theme of marine microbes that started with a discussion of the bacterium Salinispora tropica in the summer Musings [1, 2], in a consideration of the metabolically interesting marine archaeon Nitrosopumilus maritimus , which is one of the abundant ammonia-oxidizing microbes in our oceans driving global nitrogen cycling [3]. Beate Kraft (@Beate_Kraft) and Donald Canfield, from the University of Southern Denmark, tell us about its metabolic functions in ammonia oxidation, which it can then link to CO 2 fixation to enable growth.…”