Watch Scavengers Devour a Fallen Whale Carcass on the Sea Floor
The Nautilus expedition exploring the Davidson Seamount near Monterey Bay turned up something interesting last week: a relatively recent whale fall. A whale fall is when the body of a dead whale settles on the deep-sea floor, providing sustenance for the marine life in that area for decades.
While evidence of whale falls have been observed to remain on the seafloor for several years, this appears to be a relatively recent fall with baleen, blubber, and some internal organs remaining. The site also exhibits an interesting mid-stage of ecological succession, as both large scavengers like eel pouts are still stripping the skeleton of blubber, and bone-eating Osedax worms are starting to consume lipids (fats) from the bones. Other organisms seen onsite include crabs, grenadier, polychaetes, and deep-sea octopus.
The scientists were *so* excited to find this, a thriving mini ecosystem & food web in the process of formation at a depth of over 10,600 feet. They got pulled away from the carcass but went back for a closer look later.
You can read more about whale falls and their impact on deep-sea ecosystems in this New Yorker story from earlier this year.
For denizens of the seafloor, a whale fall is like a Las Vegas buffet — an improbable bounty in the middle of the desert. Rosebud had delivered about a thousand years’ worth of food in one fell swoop. The first animals to pounce had been scavengers, such as sleeper sharks and slimy, snake-like hagfish. In the course of about six months, they had eaten most of the skin and muscle. Inevitably, the scavengers had scattered pieces of flesh around the whale carcass, and native microbes had multiplied quickly around those scraps. Their feeding frenzy, in turn, had depleted oxygen in the seafloor’s top layers, creating niches for microbes that could make methane or breathe sulfate.
As Rosebud came into view, we saw colorful microbial carpets light up the screens-plush white, yellow, and orange mats, each a community of microbes precisely tuned to their chemical milieu. The whale’s towering rib cage had become a cathedral for worms, snails, and crabs, which grazed beneath its buttresses. A few hungry hagfish slithered through the skull’s eye sockets. When the cameras zoomed in, we saw that the bones were covered in red splotches. Rouse leapt from his chair and rushed to the monitors for a closer look: he suspected that the red tufts were colonies of remarkable bone-eating worms called Osedax, which had only just recently been described in a rigorous scientific study.
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