An Octopus Garden Off The California Coast

Mysterious!:

But then, just as Hercules crossed over a ridge, a curious sight floated across the screen: small, almost iridescent bulbs clinging to the seamount wall. The scientists directed Hercules down, farther into the depths.

“And sure enough, that’s where we ran into thousands and thousands of these octopus,” King said. “And we were just absolutely floored. We were just giddy.”

The scientists, led by the National Oceanic and Atmospheric Administration’s Monterey Bay National Marine Sanctuary, had alighted upon what they called an “octopus garden.” The images they captured revealed nearly 6,000 octopuses — leading scientists to estimate the total population of the area could exceed 20,000.

The discovery of the thousands of Muusoctopus robustus — or “pearl octopus,” as researchers dubbed it for the animal’s shape and opalescent shine — led a team of scientists on a five-year quest to solve the mystery: Why are there so many thousands of pearl octopuses at the foot of the Davidson Seamount, and how did they come to be living there?

The researchers visited Octopus Garden more than a dozen times to find out, and a study published last week in the journal Science Advances shows they solved one part of the mystery. The pearl octopus came to the Davidson Seamount, they discovered, to nestle into the warm crooks of its wall and brood eggs.

The ambient temperature of water around the seamount is about 35 degrees Fahrenheit, according to Monterey Bay Aquarium Research Institute scientists. But by using sophisticated marine thermometers, the researchers found that the octopuses were settling into crevices warmed by spring water, where the temperature reached nearly 51 degrees.

“So we’re still unsure exactly about what kind of geological circulation drives these springs, but essentially water’s getting heated somewhere underground there,” said Steve Litvin, a marine ecologist at the institute. “And just like a warm spring, you know, I don’t want to say ‘Old Faithful,’ but it’s bubbling up there out of the rocks.” 

“They’re in warm water, the metabolism is much faster,” King said, “so their life history has been very compressed relative to most deep-sea animals.”