highly significantp < 0.05
However, those in the DOC in fraction exhibited highly significant variability across growth stages (Fig. 2a , p < 0.05 for CRAM, p < 0.01 for protein- and lipid-like compounds, Table S3 ), while extracellular fractions such as s -DOC ex and b -DOC ex showed no significant differences ( p > 0.05, Table S3 ).