There are also some pretty significant infectious diseases in humans that come from the ocean.

It’s not exactly common, but one of the more disturbing ones I know of off the top of my head is probably Vibrio vulnificans, one of several bacteria known to cause a type of infection that goes by the lovely common name of “flesh-eating disease”, or necrotizing fasciitis to be more technical, which is literally exactly as horrific as it sounds (seriously, I wouldn’t recommend a Google image search). V. vulnificans isn’t nearly as common a cause as culprits like Staphylococcus aureus (especially antibiotic-resistant varieties), and causes a distinct form called “Type II”, but it does uniquely come from exposure to stagnant saline water, which in general isn’t something a lot of people seem to consider as big of a health hazard as they do stagnant freshwater for some reason (maybe due to a mistaken belief that the salt “sterilizes” it or something because it’s a preservative? Who knows), so it’s not always on people’s radar as much when it comes to places you might pick up a horrible disease.