In news that will surprise exactly no one who has ever wondered what happens to a whale when it dies, scientists have discovered the oldest, deepest, and most extensive whale graveyard yet known, located in the southeastern Indian Ocean. The necropolis, if you will, features fossils dating back more than five million years and reaches depths of over seven kilometers - because apparently whales have been holding funerals at depths that make most submarines nervous.
Whale falls - the technical term for dead whales that sink to the ocean floor - are not uncommon, but most have been found at depths of less than four kilometers. This newly discovered burial ground, however, extends hundreds of miles across the sea floor in the Diamantina fracture zone, a region formed between 60 and 50 million years ago as Australia and Antarctica drifted apart. Because nothing says "eternal rest" like a tectonic breakup.
Dr. Giovanni Bianucci of the University of Pisa, a co-author of the study published in Nature, noted that the discovery shows "these extreme and unexplored environments are home to species and ecosystems still unknown to science." In other words, we are still far from understanding the true biodiversity of our planet, which is a polite way of saying the ocean has been keeping secrets.
The team, including researchers from China, Italy, and New Zealand, used a submersible to explore the area, conducting 32 dives and finding 485 whale-fossil sites, plus five modern whale carcasses in an advanced stage of decomposition. Because nothing says "scientific breakthrough" like rotting whale remains.
The largest carcass discovered was a five-meter-long skeleton of an Antarctic minke whale. They also found remains of extinct species, including a fossilized skull from a beaked whale called Pterocetus benguelae, dated to 5.3 million years ago, and another from a new species they named Pterocetus diamantinae. Because if you're going to find a new species, you might as well name it after the trench where you found it.
The decaying carcasses were home to a diverse array of life, including crustaceans, mollusks, bone-eating worms, and brittle stars. Many species may be new to science, which is a fancy way of saying the ocean floor is a buffet for weird creatures.
Stephen J. Godfrey of the Calvert Marine Museum described the graveyard as "a truly unique discovery," comparing the research to "a trailer for the first in a series of epic movies." Because nothing says blockbuster like 485 whale skeletons.
Professor Jon Copley of the University of Southampton, who was not involved in the work, called it "an exciting and rare discovery," noting that whale falls are island-like habitats for deep-sea animals, including species related to those thriving at hydrothermal vents. But unlike those hot springs, whale falls cannot be detected remotely - so scientists have to rely on good old-fashioned deep-sea spelunking.
Copley also pointed out the puzzle of finding nearly 800 skeletons per square kilometer, including both shallow-diving filter-feeders like minke whales and deep-diving beaked whales. The researchers suggest this necropolis likely sits on a migration route for filter-feeders, while also being a good hunting ground for deep-diving squid-eaters - though perhaps pushing them "perilously close to their limits" as they dive into this crack in the ocean floor. Because even whales need to know their limits.