Novel adaptive immune systems in pristine Antarctic soils.

Antarctic environments are dominated by microorganisms, which are vulnerable to viral infection. Although several studies have investigated the phylogenetic repertoire of bacteria and viruses in these poly-extreme environments with freezing temperatures, high ultra violet irradiation levels, low moisture availability and hyper-oligotrophy, the evolutionary mechanisms governing microbial immunity remain poorly understood. Using genome-resolved metagenomics, we test the hypothesis that Antarctic poly-extreme high-latitude microbiomes harbour diverse adaptive immune systems.

A Global Relationship Between Genome Size and Encoded Carbon Metabolic Strategies of Soil Bacteria.

Microbial traits are critical for carbon sequestration and degradation in terrestrial ecosystems. Yet, our understanding of the relationship between carbon metabolic strategies and genomic traits like genome size remains limited. To address this knowledge gap, we conducted a global-scale meta-analysis of 2650 genomes, integrated whole-genome sequencing data, and performed a continental-scale metagenomic field study.

Dung predicts the global distribution of herbivore grazing pressure in drylands.

Dryland grazing sustains millions of people worldwide but, when poorly managed, threatens food security. Here we combine livestock and wild herbivore dung mass data from surveys at 760 dryland sites worldwide, representing independent measurements of herbivory, to generate high-resolution maps. We show that livestock and wild herbivore grazing is globally disconnected, and identify hotspots of herbivore activity across Africa, the Eurasian grasslands, India, Australia and the United States.

Global Relative Importance of Denitrification and Anammox in Microbial Nitrogen Loss Across Terrestrial and Aquatic Ecosystems.

Denitrification and anaerobic ammonium oxidation (anammox) are the major microbial processes responsible for global nitrogen (N) loss. Yet, the relative contributions of denitrification and anammox to N loss across contrasting terrestrial and aquatic ecosystems worldwide remain unclear, hampering capacities to predict the human alterations in the global N cycle. Here, a global synthesis including 3240 observations from 199 published isotope pairing studies is conducted and finds that denitrification governs microbial N loss globally (79.