Hi,

Has anyone heard of freshwater patches occurring in the ocean? And if so, do you know the cause of it?

The only (vague) reason I've come across is that it comes from an aquifer under the ocean. Does anyone have any other ideas?

Fresh water fissures are found in the ocean but only where there is lava present to funnel it 'up'. The 'aquifer' you read about is one of these lava 'funnels'.. They commonly occur only where there is volcanic activity as in the pacific islands. It isn't a vague reason, but fact.

You can read about it by googling, just as you say, 'fresh water patches in the ocean'. Relatively simple and good reading.