This happens along the coastline around America quietly many times a year. Generally the outflow pipes are 1-2 miles offshore so if you aren't in a boat you don't see it, but as a sailor I see it two or three times a year in my home waters. This is why I always scoff at people who talk about MPG or global warming or anything else - we don't even separate storm run off from sewage in this country because a lot of towns saved some money by running one set of pipes - why are you worrying about possible effects of CO2 when there are massive effects happening from something we have the technology to solve today.