Deep sea octopus gardens intrigue scientists
This is a repost blog.
Original stories appeared on KAZU and in Scientific American.
Hat tip to Metafilter for surfacing this story.
8 Nov 2019: Deep sea octopus gardens intrigue scientists (click through for many beautiful images)
By Erika Mahoney/KAZU
A team of scientists spent the week exploring an octopus garden in the Monterey Bay National Marine Sanctuary. The garden is a nursery of sorts, a place where hundreds of female octopuses come to lay and take care of their eggs. Brimming with brooding moms, it’s the largest octopus garden ever discovered.
KAZU News connected with some of the local scientists involved in the expedition while they were out at sea.
“It’s almost freezing down there. It’s clearly a place humans can’t go scuba diving,” said Chad King, lead scientist on the cruise and a research specialist with the Monterey Bay National Marine Sanctuary.
So, they rely on underwater robots. The expedition was a team effort between NOAA’s Office of National Marine Sanctuaries and Ocean Exploration Trust, a nonprofit that owns and operates the trip’s exploration vessel. It’s called E/V Nautilus. Onboard were two remotely operated vehicles, or ROVs, that can operate in the deep sea.
King says these robots, called Hercules and Argus, worked together to collect samples and capture video. As the scientists watched the footage inside the Nautilus, the public has been able to see it too, from their living rooms, classrooms and more.
Lead Scientist Chad King views underwater footage of the octopus garden inside the research vessel’s control room.
The team’s dives into the octopus garden were live streamed at nautiluslive.org. Footage showed hundreds of lavender-colored octopuses nestled among rocks and a few clinging to the robots.
It’s called the “octopus garden” in honor of the Beatles song. But also because octopuses bury the shells of the animals they eat like underwater gardners.
King says the garden is a nursery to over 1,000 female octopuses who are brooding.
“So brooding is essentially taking care of their eggs. It’s almost like a bird in a nest, nesting their eggs. So they protect them because these eggs most likely would be preyed upon by shrimp and other creatures,” King said.
In fact, a highlight clip captured a face off between a newborn octopus and a shrimp.
Female octopuses come here to lay and take care of their eggs. The moms die soon after.
King says this is only the second cluster of brooding octopuses ever found and by far the largest. It’s located about 50 miles off the coast of San Simeon in the Davidson Seamount Management Zone. The Seamount is an extinct volcano that last erupted about 10 million years ago. It’s also home to corals and sea sponges the size of sofas. The zone was added to the protected Monterey Bay National Marine Sanctuary in 2008.
The octopus garden was first discovered in 2018 during the tail end of an expedition. King was onboard and describes the moment as a slow realization. They kept running into more and more octopuses.
“And that’s when it really hit us. This is special. This is unusual. We need to know what’s going on here,” King said.
And that’s been the mission of this trip, to figure out why these octopuses are congregating here. The underwater robots took samples from the area and collected temperature readings. King says they’ve discovered that warmer water is seeping out of the seafloor here. You can even see it shimmering in the video footage sometimes, like when asphalt shimmers on a hot summer day.
“So there’s something going on there. There’s some relationship attracting the octopus to these areas,” said King.
The public was also able to ask questions about the garden via Nautilus Live. Questions came in from around the world. Amity Wood, Education and Outreach Coordinator for the Monterey Bay National Marine Sanctuary, was also onboard. She says they video chatted with students from across the U.S.
“Usually we get our science through produced documentaries or scripted television shows. But in this case, it’s, you know, unfiltered livestream science,” Wood said.
During the expedition, scientists also captured video footage of this whale fall.
The team onboard also captured footage of a dumbo octopus, a flapjack octopus and a whale fall. A whale fall is a whale carcass that’s sunk to the ocean floor and provides nutrients for all kinds of creatures.
Although the six day trip has wrapped up, people can still view highlight videos on Nautilus Live and all of the video footage will be uploaded to YouTube.
23 Aug 2023: The Hot Secret behind a Deep-Sea ‘Octopus Garden’ (click through for images)
By Stephanie Pappas in Scientific American
Thousands of usually solitary octopuses gather to brood eggs in a special spot off California
Thousands of deep-sea octopuses gather on the flanks of a seamount off California’s coast. But until recently, scientists weren’t sure why these otherwise solitary animals were congregating. New research suggests they are seeking warmth to help their babies hatch more quickly.
The Davidson Seamount’s “Octopus Garden” was discovered in 2018, when researchers onboard the Ocean Exploration Trust research vessel Nautilus were exploring a rocky spot on the seafloor that was about two miles below the surface. The team spotted a pair of octopuses through a camera on a remotely operated vehicle (ROV), says Amanda Kahn, an ecologist at Moss Landing Marine Laboratories and San Jose State University, who was on the Nautilus that day. After observing the pair for a bit, the operators started to lift the ROV off the rocks to move on—until they saw something unusual. “Up ahead of us were streams of 20 or more octopuses nestled in crevices,” Kahn says.
Octopuses are usually solitary, so it was immediately clear that something strange was happening. The researchers dropped their plans and started to investigate, discovering many more of the pearly-hued, grapefruit-sized octopuses—as well as strange shimmers in the water that suggested the presence of some sort of underwater fluid seeps or springs.
Now, after more than five years and multiple return trips to the Octopus Garden, the researchers estimate that the 1.29-square-mile area may contain more than 20,000 of the cephalopods at any given time. Females of the Muusoctopus robustus—the octopus species found in the garden—hover protectively over their eggs, their arms facing up, ready to swipe away any potential predators.
“This Octopus Garden is by far the largest aggregate of octopuses known anywhere in the world, deep-sea or not,” says James Barry, a benthic ecologist at the Monterey Bay Aquarium Research Institute and leader of a new study, published on Wednesday in Science Advances, that reveals why the animals are gathering. Barry, Kahn and their colleagues found that the octopuses are there to find cozy spots for their nests.
By placing sensors around nests, the researchers discovered that the octopuses were choosing places for their eggs where the temperature hovered between 41 and 51.8 degrees Fahrenheit. By contrast, the surrounding ocean waters are about 34.9 degrees F. Based on patterns seen in other deep-sea octopuses, brooding eggs at 34.9 degrees F would lead to extremely slow development rates, Barry says, with eggs incubating for at least five years and perhaps up to 13 years.
By repeatedly observing the female octopuses and nests in the garden, the research team found that these octopuses were instead hatching their eggs in a little less than two years, Barry says. That’s very close to what established equations would estimate for water temperatures in the 40s, he adds. A quicker incubation period likely means fewer offspring will be lost to predation, parasites or other threats. “It’s a neat sort of accelerator,” Kahn says.
The octopus breeding ground also creates a sort of oasis for other ocean life, the researchers found. Octopus moms die after brooding, and the concentration of octopus bodies in the area injects a source of carbon—a crucial nutrient—into the local ecosystem. “We’re now interested in getting back there and looking at the halo effect of the breeding ground,” Barry says.
The researchers also found a smaller breeding site, which they call the Octocone, about five miles from the Octopus Garden. These sites (and similar nurseries off Costa Rica and Vancouver, British Columbia) are the only ones where this kind of octopus accumulation is known, says Beth Orcutt, a senior research scientist at Bigelow Laboratory for Ocean Sciences in Maine, who was not involved with the Davidson Seamount study but was one of the discoverers of the nursery off Costa Rica. “We predict there should be more,” Orcutt says. “That’s because there are tens of thousands of these small seamounts in the Pacific Ocean, but they just haven’t been explored.”
The new study was unique because the scientists had access to research vessels and ROVs for repeated visits to the site, says Jorge Cortés, a marine biologist at the Center for Research in Marine Sciences and Limnology at the University of Costa Rica, who co-discovered the Costa Rican nursery but was not involved in the new research. Costa Rica depends on international science collaborations for research vessel access, Cortés says, which limits the kinds of studies that can be done. He and his team placed temperature and water-chemistry sensors in the Costa Rica nursery this year, however, and they will return to collect data after six months, potentially shedding more light on another octopus breeding ground.
The warm springs the octopuses at the Davidson Seamount seem to seek are much more subtle features than the dramatic hydrothermal vents that spew out what looks like black or white smoke on the ocean floor. In the case of the Davidson Seamount, it was the octopuses that were noticeable before the warm water, Kahn says.
The Octopus Garden is within the Monterey Bay National Marine Sanctuary, so it is somewhat protected. The researchers say that many other obscure sites in need of conservation may still be out there, however. “There are some very important breeding grounds that are sites we really need to understand and protect,” Barry says.
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