The ocean depths are home to myriad species of microbes, mostly hard to see but including spaghetti-like bacteria that form whitish mats the size of Greece on the floor of the Pacific, scientists said on Sunday.

The survey, part of a 10-year Census of Marine Life, turned up hosts of unknown microbes, tiny zooplankton, crustaceans, worms, burrowers and larvae, some of them looking like extras in a science fiction movie and underpinning all life in the seas.

“In no other realm of ocean life has the magnitude of Census discovery been as extensive as in the world of microbes,” said Mitch Sogin of the Marine Biological Laboratory in Woods Hole, Massachusetts, head of the marine microbe census.