Distinct genes and microbial communities involved in nitrogen cycling between monsoon- and westerlies-dominated Tibetan glaciers.

Abstract

The Tibetan Plateau (TP) glaciers are influenced by monsoon and westerlies. They are highly sensitive to climate change, with atmospheric nitrogen deposition significantly impacting microbial communities and functions. However, key uncertainties persist regarding biogeography and drivers of genes and microbial communities involved in nitrogen cycling. Here, we investigate the diversity and transcriptional activity of microbial communities and nitrogen-cycling genes using 85 metagenomes and 28 metatranscriptomes from the ablation zone of 21 TP glaciers. Our results show that over 90% of the glacial taxa possess the potential for nitrogen metabolism, with ~33% exhibiting transcriptional activity. Moreover, monsoon-dominated glaciers present greater microbial diversity and higher prevalence of nitrogen-fixing genes than westerlies-dominated glaciers, linked to higher temperatures. Comparatively, the latter show elevated genomic potential for nitrous oxide emissions, likely due to higher nitrate concentrations. These findings establish temperature-nitrogen co-regulation of microbial nitrogen transformations, critical for predicting climate feedback in the extreme environment.