The expanding knowledge of marine Thaumarchaeota: from new groups to new functions

Abstract:

Thaumarchaeota is an important microbial group in the global ocean, accounting for 20%-40% of the total marine prokaryotic plankton. As a group of chemautotrophs, Thaumarchaeota members are able to oxidize ammonia and leverage the released energy to fix inorganic carbon in the dark. They thus play a crucial role in the biogeochemical cycling of carbon and nitrogen. Thaumarchaeota are the major driver of ammonia oxidization in the ocean. The primary production by Thaumarchaeota through chemosynthesis serves as an important energy source for marine microorganisms, especially those in the deep-sea environments. With increasing efforts, the knowledge on the physiological and metabolic features of this group is expanded. This includes the evidence of heterotrophic metabolism, the discovery of thaumarchaeotal groups with no ammonia oxidation capacity in the deep sea, and the production of oxygen, nitrous oxide, and dinitrogen under anaerobic conditions. These studies reveal the new mechanisms of Thaumarchaeota in participating in the marine biogeochemical cycling and regulating climate change, which provide novel insights and perspectives for further studies and culture. In this study, we review new discoveries about marine Thaumarchaeota in recent years in terms of community composition, environmental adaptation, ecological function, evolutionary history, and culture status, with an aim of improving the understanding of this group.