Scientists at the Monterey Bay Aquarium Research Institute (MBARI, for its acronym in English), a 90-centimeter long mammoth tusk found in the bed of the Pacific Ocean at a depth of 3 kilometers.
The tusk was found by pilot Randy Prickett and scientist Steven Haddock, who made a particular observation while exploring the seabed aboard the R / V Western Flyer in 2019, though at that moment they could not extract more than a small piece, but in July 2021 MBARI returned to retrieve the complete sample.
Thanks to this, researchers from the UC Santa Cruz Institute of Genomics, the Department of Earth and Planetary Sciences at the University of California, Santa Cruz (UCSC), and the Museum of Paleontology at the University of Michigan (UM), have confirmed that the tusk, approximately one meter long, is from a Columbian mammoth (Mammuthus columbi).
The cold, high-pressure environment of the deep sea uniquely preserved the tusk, giving the researchers the opportunity to study it in greater detail. Now a CT scan will reveal the internal structure full three-dimensional view of the tusk and more information about the animal’s history, such as its age.
“You start to ‘expect the unexpected’ when you explore the depths of the sea, but it still amazes me that we come across the ancient tusk of a mammoth”, Haddock said. “We are grateful to have a multidisciplinary team analyzing this extraordinary specimen. Our work to examine this exciting discovery is just beginning and we look forward to sharing more information in the future. ”
“The deep-sea conservation environment of this specimen is different from almost everything we’ve seen elsewhere,” said University of Michigan paleontologist Daniel Fisher, who specializes in studying mammoths and mastodons. “Other mammoths have been recovered from the ocean, but generally not from depths of more than a few tens of meters.”
Fisher and his colleagues at the UM Museum of Paleontology will use their knowledge of the structure and composition of mammoth tusks to analyze CT scans of the specimen.
A team of researchers from UCSC’s Department of Earth and Planetary Sciences will investigate when and how the tusk may have reached the depths of the coast.
The team believes it could be the oldest and best-preserved mammoth tusk recovered from this region of North America. Dating of the tusk is being performed by the UCSC Laboratory of Geochronology led by Terrence Blackburn, associate professor of Earth and planetary sciences.
Blackburn analyzed radioisotopes to show that the tusk it is much more than 100,000 years old. “Our estimate of the age of the tusk is largely based on the natural radioactive decay of certain isotopes of uranium and thorium imparted to the tusk from the ocean. If the tusk had been found on the ground, deciphering its history would not be so easy ”, Blackburn said.
Researchers from the UCSC Paleogenomics Laboratory led by Beth Shapiro, professor of ecology and evolutionary biology, plan to sequence the ancient DNA of the specimen, which could provide valuable information on how mammoths colonized North America. Katherine Moon, a postdoctoral researcher in Shapiro’s lab, accompanied Haddock on the July cruise to retrieve the complete specimen.
Shapiro and Moon will retrieve the ancient DNA preserved within the tusk matrix, which they will compare with DNA that has already been recovered from other mammoths. “Specimens like this present a unique opportunity to paint a picture of both an animal that used to be alive and the environment in which it lived,” Shapiro said. “Mammoth remains from continental North America are particularly rare, so we hope that the DNA from this tusk will do much to refine what we know about mammoths in this part of the world.”