SAA exhibits similar behavior across different SOM types, with a slightly higher probability of encountering HS molecules in the SOM III system. Compared to HS, the probability of being surrounded by water is approximately four times higher, indicating a relatively low but non-negligible SAA concentration within the HS phase. This explains the observed correlation between SAA diffusion and water diffu- sion in Figure . Furthermore, the results suggest that at high water contents, SAA diffusion is primarily influenced not by direct interactions with HS molecules but rather by the structural and spatial arrangement of HS molecules, which modulates the mobility and flow of the surrounding water beads.