California grassland soil stable isotope study following the Water Year

Mediterranean grasslands, vital natural and agricultural ecosystems, experience seasonal variation in water content that likely affect microbial activity. The active parts of soil community have an outsized impact on the metabolic potential and microbial population thus, to understand how changes in water regimes and soil depth affect active microbiome populations and the expression of ecophysiological traits we used metagenomics-informed stable isotope probing to investigate how the activities of microorganisms in Angelo Reserve (2160 mm rainfall) and Hopland (956 mm rainfall) soil change over depth and the seasons. We measured a variety of edaphic properties across three crucial periods of the water year. This yielded a total of 89 biological samples (two ecosystems, five timepoints, three core replicates, and three depths) with 890 fractionated samples and 178 unfractionated DNA samples sequenced.