WASHINGTON (AP) — Most octopuses lead solitary lives. So scientists have been startled to search out hundreds of octopus huddled collectively, defending their eggs on the backside of the ocean off the central California coast.
Now researchers could have solved the thriller of why these pearl octopus congregate: Warmth seeping up from the bottom of an extinct underwater volcano helps their eggs hatch sooner.
“There are clear advantages of basically sitting in this natural hot tub,” mentioned Janet Voight, an octopus biologist on the Discipline Museum of Pure Historical past in Chicago and co-author of the research, which was revealed Wednesday in Science Advances.
The researchers calculated that the heated nest location greater than halved the time it took for eggs laid there to hatch — lowering the chance of being munched by snails, shrimp and different predators.
The nesting web site, which the scientists dubbed an “octopus garden,” was first found in 2018 by researchers from the Monterey Bay Nationwide Marine Sanctuary and different establishments. The staff used an underwater distant car to movie the throng of practically 6,000 octopus nesting 2 miles deep.
The octopus — concerning the dimension of a grapefruit — perched over their eggs laid on rocks heated by water seeping up from the ocean ground.
“It was completely incredible – we suddenly saw thousands of pearly-colored octopus, all upside down, with their legs up in the air and moving around. They were pushing away potential predators and turning over their eggs,” for a fair move of water and oxygen, mentioned Nationwide Oceanic and Atmospheric Administration marine biologist Andrew DeVogelaere, a research co-author.
Solely the hazy shimmer of escaping sizzling water assembly the frigid sea alerted the researchers to the hydrothermal seep. However they nonetheless didn’t know precisely why the octopus had gathered there.
For 3 years, scientists monitored the positioning to know the hatching cycle, recording each the developmental stage of eggs at 31 nests and the inevitable deaths of octopus mothers.
“After the hatchlings come out of the nest and swim off immediately into the dark, the mothers, who never left their nest and never appeared to feed during nesting, soon die,” mentioned James Barry, a biologist on the Monterey institute and co-author of the research.
The researchers discovered that eggs at this web site hatch after about 21 months — far shorter than the 4 years or extra it takes for different recognized deep-sea octopus eggs.
“Usually, colder water slows down metabolism and embryonic development and extends life span in the deep sea. But here in this spot, warmth appears to speed things up,” mentioned Adi Khen, a marine biologist on the Scripps Establishment of Oceanography, who was not concerned within the research.
Mike Vecchione, a Smithsonian Nationwide Museum of Pure Historical past zoologist who was not concerned within the research, praised the researchers’ tenacity “to collect a lot detailed information about such a distant location.”
Such octopus gardens “may be widespread and really important in the deep sea, and we just previously knew very little about them,” he mentioned. “There’s still so much to discover in the deep sea.”
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