[kuhewa]

Well, you have the same thing happening in marine sediments as well with interstitial organisms, and really in the water itself you have this still fairly poorly understood food web (see: Marine microbial loop) occuring before your reach a size of familiar organisms.

Different terrestrial and marine habitats and assemblages come to mind where one may be more complex than another but overall if the degree of niche partitioning at any given trophic level was a wash between land and sea water, I think marine may take the cake on complexity just due to the webs being longer and thus room for more edges between nodes https://pubmed.ncbi.nlm.nih.gov/27322123/