When a great whale dies and its lungs deflate, its body, slightly denser than seawater, sinks fast enough to pass the midwater scavengers, and cold and pressure keep gases dissolved so it reaches the deep seafloor intact. The first clue came in 1854, when a new mussel species was taken from floating whale blubber, and in the 1960s trawlers hauled up Osteopelta limpets attached to whale bone. On February 19, 1977, Navy pilots in the bathyscaphe Trieste II spotted a stripped gray whale skeleton off Santa Catalina, California, and in 1987 oceanographer Craig Smith’s Alvin team found a living whale fall community 1,240 meters down in the Catalina Basin.

The ecosystem runs in four stages. Hagfish, sleeper sharks, and eelpouts strip 40 to 60 kilograms of tissue a day for months up to a year and a half, then opportunists clean up for up to about four and a half years. For 50 to 100 years, bacteria digest the lipids in the bones and release hydrogen sulfide, which sulfur loving bacteria use for chemosynthesis, feeding clams and mussels, before bare bones become a reef. Eocene and Oligocene whale falls lack these communities because older whales had less fatty bones.

• Osedax, bone eater, has no mouth or stomach and uses root-like structures and acid to bore into bone.
• Sulfur reducing bacteria and methane producing archaea coexist at whale falls instead of competing.
• Whale shark and mobulid ray carcasses stall after the scavenger stage because cartilage skeletons lack the fat.
• A 40 ton carcass holds about two tons of carbon, equal to 2,000 years of normal carbon flux to that spot.
• Models estimate that industrial whaling cut deep sea biomass by more than 30 percent.