Overlooked Genetic Diversity of Ammonia Oxidizing Archaea Lineages in the Global Oceans

Abstract

Plain Language Summary In the ocean, ammonia oxidizing archaea (AOA) are widely distributed microbes that play important roles in the marine nitrogen cycling and the emission of the highly potent greenhouse gas (N2O). However, the majority of the marine AOA are currently uncultivated; the physiology of marine AOA and the factors that mediate their distribution still remain unclear. In this study, we have analyzed the fine-scale phylogenetic diversity and community structures of the AOA in the global ocean. Based on the results, the genetic diversity of marine AOA might be overlooked in the past since highly diverse groups that showed differential distribution patterns in the previously defined AOA ecotypes are found. Besides, by analyzing the correlations of their distributions with the varied environmental conditions in the global oceans, the diverse AOA groups were delineated with particular physiochemical factors. At a finer resolution than the previously defined ecotypes, our findings provide new insights into the determinants and the ecophysiology of the widely distributed but uncultivated AOA groups.