So, I’ve definitely heard of some of this kind of phenomena…marine “snot” if you will. There can be all kinds of conglomerations of detritus (the dead stuff, the small particles sinking down to the ocean bottom). But not sure if I’d want to be swimming/snorkeling with it.
And these blobs are apparently on rise due to warming trends. Suprise, suprise these mucousy plumes harbor bacteria, sort of like some marine cold…
A Bit of Stardust 