The Mysterious Blob

Could be!

That's certainly an original idea.

It is less scary than dead algae mats presaging oceanic calamity.

0_o

Cthulhu using Earth as a toilet is less scary than what we are doing to our own planet. Yikes.

Oh, shit.

I have seen algae mats surface in ponds, and it's bad enough. If that happens to the ocean, much doom awaits.

This is disturbingly plausible as an explanation. It accounts for the fact that the phenomenon was unfamiliar. And it would be a lot worse than, say, bacteria that eat plastic or oil and leave gunk behind.

Yes, I'm aware of the potential for methane doom. Some scientists theorize that previous global eruptions of methane may have contributed to or caused mass extinctions. At any rate it could shift the Earth's atmosphere from "overheating" to "actually on fire."

>>Although, if it's a result of something else changing in the environment, it's still bad, since much of the bottom ecosystem is dependent on these bacterial mats.<<

Yeah ... we better hope that global warming is caused by human activities, because then it is at least theoretically within our power to affect the process. If it's caused by something else, we probably can't influence, and if we can't adapt, we're just doomed. That would suck.

>> [it would be like all the grass dying off on the African Savannah.]<<

Or your lungs falling out when you cough. Some people forget how much of Earth's oxygen comes from the oceans (i.e. from algae and such). Any large-scale changes in an ecosystem generally mean that something is severely out of balance. Vast algae blooms and collapses worry me. Dying coral reefs worry me. A whole new flavor of doom is not what I need.

That is very weird.