GLOBAL DISTRIBUTIONS OF FRESHWATER AMMONIA-OXIDIZING ARCHAEA BASED ON ANALYSIS OF THOUSANDS OF METAGENOMES

Reilan Garczynski Julian Damashek The high abundance of ammonia-oxidizing archaea (AOA) in oligotrophic marine waters and soils, along with physiological data from cultivated strains, suggests many thrive in low-nutrient environments, yet studies in freshwaters have found abundant and diverse AOA in both low- and high-nutrient waters. To determine global ecological patterns of freshwater AOA, we competitively mapped >100 billion sequences from >1,900 lake, river, and stream water metagenomes to a genome database of all Nitrososphaeria (formerly “Thaumarchaeota”) genomes in GTDB. We then summarized the relative abundance of Nitrososphaeria genera and metagenomic operational taxonomic units (mOTUs, consisting of genomes with ≥95% average nucleotide identity). Overall, metagenomes from tropical systems and deep lakes consistently had the highest relative AOA abundance. There were distinct groups of metagenomes with highly abundant and low-diversity communities of Nitrosotenuis, Nitrosotalea, or Nitrosoarchaeum. For example, many equatorial waters had large AOA communities composed almost entirely by Nitrosotenuis, often dominated by a single mOTU related to MAGs from the Amazon River. However, many other environments had far greater archaeal diversity, including a mix of genera commonly found in acidophilic, terrestrial, and marine environments. This study demonstrates the power of large meta-analyses to help identify the global ecology of specific microbial lineages.

Primary Presenter: Reilan Garczynski, Hamilton College (rgarczyn@hamilton.edu)

Authors:

Reilan Garczynski Garczynski, Hamilton College  (rgarczyn@hamilton.edu)

Julian Damashek, Hamilton College  (jdamashe@hamilton.edu)