Soil bacterial diversity inventories along small-scale stress gradients in the Arctic, Antarctic, and Chihuahuan Deserts (2022-2023)

Bacteria form the foundation of soil ecosystems in desert ecosystems, driving soil function, diversity, and ecology. Soil physicochemistry is largely dictated by larger topographical variations and can directly drive bacterial community composition and the relationships within. Bacteria may form complex networks of interactions with other bacteria and other soil taxa that have implications for emergent properties such as diversity and stability, but the way these interactions are impacted by environmental stressors remains poorly understood. Here, we sampled soil bacterial communities of three desert ecosystems at different latitudes: the McMurdo Dry Valleys, Antarctica; the northern Chihuahuan Desert, Jornada Experimental Range (JER), New Mexico, USA; and the Arctic tundra at the Canadian High Arctic Research Research Station (CHARS), Victoria Island, Nunavut, Canada. In each system, a holistic stress-gradient was sampled based on local topographical variation, vegetation cover, and water availability. Sampling along the stress-gradient was conducted at four distinct stress levels, namely lower elevation with vegetation cover, lower elevation without vegetation cover, higher elevation with vegetation cover, and higher elevation without vegetation cover. To allow robust biodiversity inference and co-occurrence network construction, 30 replicates were collected at each stress level, and this was done at two independent stress gradients for the Chihuahuan Desert and Arctic sites. The Antarctic samples consisted of two independent stress gradients, one ranging from low, middle to high elevation without vegetation cover, and one consisting of two levels with and without vegetation cover. For each site, soil pH and gravimetric water content was also measured. Each replicate was then sequenced on an Illumina MiSeq for 2x250 paired-end sequencing of the 16S rRNA marker. Sequences were archived in NCBI under BioProject PRJNA1098956, with accession numbers included herein.