Chemosynthetic and photosynthetic bacteria contribute differentially to primary production across a steep desert aridity gradient

• DOI: 10.1038/s41396-021-01001-0
• Publication Date: 2021-05-25T16:03:08Z
• Authors: Sean K Bay; David W Waite; Xiyang Dong; Osnat Gillor; Steven L Chown; Philip Hugenholtz; Chris Greening
• Keywords: Chemosynthesis; Biogeochemical Cycle; Primary producers

Abstract Desert soils harbour diverse communities of aerobic bacteria despite lacking substantial organic carbon inputs from vegetation. A major question is therefore how these maintain their biodiversity and biomass in resource-limiting ecosystems. Here, we investigated desert topsoils biological soil crusts collected along an aridity gradient traversing four climatic regions (sub-humid, semi-arid, arid, hyper-arid). Metagenomic analysis indicated vary capacity to use sunlight, compounds, inorganic compounds as energy sources. Thermoleophilia, Actinobacteria, Acidimicrobiia were the most abundant prevalent bacterial classes across both biocrusts. Contrary classical view that taxa are obligate organoheterotrophs, genome-resolved suggested they metabolically flexible, with also atmospheric H2 support respiration often fixation. In contrast, Cyanobacteria patchily distributed only certain Activity measurements profiled oxidation, chemosynthetic CO2 fixation, photosynthesis varied aridity. Cell-specific rates consumption increased 143-fold gradient, correlating abundance high-affinity hydrogenases. Photosynthetic primary production co-occurred throughout dominant biocrusts chemosynthesis arid hyper-arid soils. Altogether, findings suggest lineages inhabiting hot deserts different strategies for acquisition depending on resource availability. Moreover, highlight previously overlooked roles Actinobacteriota producers trace gases critical sources supporting productivity resilience