Fig. 4
From: Microbial carbon oxidation in seawater below the hypoxic threshold
Temporal dynamics of mesocosm microbial communities under hypoxic and oxic treatments. (a) Non-Metric Multidimensional Scaling (NMDS) plot of Bray–Curtis dissimilarities from 16S rRNA amplicon sequences (ASVs). Day -4 represents the initial community derived from a natural seawater inoculum from Yaquina Bay, while day 0 signifies the onset of oxygen delivery. The communities in the hypoxic and oxic treatments exhibit noticeable divergence over time, indicating a specialized microbiome colonized the hypoxic treatment between days 14–100. The divergence is canonically unexpected due to the ample oxygen availability at ca.7.1 µM O2. Stress value for the NMDS analysis was 0.07. (b) Microbial community composition at the family level. Microbial communities in oxic and hypoxic treatments showed initial similarities on day 0 but diverged notably by day 44. On day 44, the oxic treatment was dominated by SAR11 Clade 1, while the hypoxic treatment exhibited an increase in an unclassified SAR86 strain. At the terminal time point, both treatments displayed a predominance of an archaeal population of ammonia-oxidizing Nitrosopumilaceae.
