The antibiotic erythromycin binds specifically with the 50s portion of a ribosome. what effect do you expect this to have?

The antibiotic erythromycin binds specifically with the 50s portion of a ribosome and technically, only prokaryotes have a 50S ribosome (larger subunit of prokaryote’s 70s ribosome). So the process happens in prokaryotic organisms (mostly bacteria) and as we know, erythromycin is an antibiotic — performing a bactericidal activity which kills a bacteria or prokaryote.

The zone your looking for is the intertidal zone.