Saturday, January 7, 2017
Think kittens are cute? Try Casper, the Friendly Octopod.
It seemed simple: There are deposits of valuable minerals
just lying on the sea floor for collecting—why not do it?
Now, researchers in Hawai`i are finding there are ecosystems
that seem entirely dependent on these deposits—not the least of them a ghostly cute
little white octopus relative nicknamed “Casper.”
(Image: The newly described octopod nicknamed Casper, photographed
in 2011 near Ka`ena Ridge. Credit: Woods Hole Oceanographic Institute and the
University of Hawaiʻi.)
It turns out that manganese nodules nearly a mile deep
around the Islands grow a specific kind of sponge, and that Casper lays its
eggs on those sponges.
Marcie Grabowski of the University of Hawai`i, wrote about this little biological-geological community on December 27, 2016.
The eight-legged Casper was spotted for the first time
during a submersible dive in the Ka`ie`ie channel between Kaua`i and O`ahu.
Geologists were trying to determine whether a submarine ridge that extends
beyond Ka`ena Point on O`ahu was part of the Wai`anae volcanic range or a
separate volcano.
Raising Islands covered that issue in 2014 here. It's O`ahu's third volcano.
The rock hounds saw this cut little white octopus, although they did not immediately realize that they may have been the first people to ever see it.
“Being a team of geologists, not cephalopod experts, we
didn’t realize it was a previously unrecognized species,” said geologist
Deborah Eason, of the University of Hawai`i at Mānoa’s School of Ocean and
Earth Science and Technology.
Since them, new research has shown that Casper and related
species inhabit seafloor habitats across the Pacific. A new paper in the journal Current Biology discusses that.
It shows that at least two species of octopods are active in
water nearly a mile deep—they’ve been seen at more than 4,000 feet. And that
they seem to be particularly linked to manganese rich nodules and crusts, where
they attach their eggs to the stalks of dead sponges.
The sponges may be using the manganese-rich rocks, not so
much for the manganese, but simply because they’re the only hard anchoring
points in an otherwise muddy seafloor.
“This is the first time such a specific mineral-biota
association has been observed for incirrate octopods. ... broods consisted of
approximately 30 large (2.0–2.7 cm) eggs. Given the low annual water
temperature of 1.5 degees C, it is likely that egg development, and hence
brooding, takes years,” wrote the authors of that paper.
They clearly made the point that if you start mining the
seafloor, it’s going to have an impact on the sponges and the octopi.
“The brooding behavior of the octopods we observed suggests
that, like the sponges, they may also be susceptible to habitat loss following
the removal of nodule fields and crusts by commercial exploitation,” said the
authors, who are led by Autun Purser, of the Alfred Wegener Institute,
Helmholtz Centre for Polar and Marine Research, in Bremerhaven, Germany. Eason
is a co-author on that paper.
Casper the octopod has, since its discovery, gone viral for
its similarity in appearance to the cartoon character, Casper the Friendly
Ghost. The deep-sea critter now gets millions of hits on internet searches for
news sites, television reports, magazines, newspapers and blogs. Scientific
American had a piece here.
© Jan TenBruggencate 2017
Posted by Jan T at 9:03 AM
Labels: Botany, Conservation, Fisheries, Geology, Marine Issues, Oceanography, Reefs, Volcanoes, Zoology
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