Wednesday, 5 October, 2022
HomeScientiFixAn ancient mammoth tusk buried deep in Pacific Ocean & ‘newcomer’ dwarf...

An ancient mammoth tusk buried deep in Pacific Ocean & ‘newcomer’ dwarf galaxies in Milky Way

ScientiFix, our weekly feature, offers you a summary of the top global science stories of the week, with links to their sources.

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Ancient mammoth tusk found deep in the ocean

While exploring an underwater mountain located 300 kilometres off the shore of California and 3,070 metres deep, a team of scientists discovered an ancient mammoth tusk.

The tusk was first spotted during an expedition in 2019, but the team was only able to collect a small piece at the time. The team returned in July 2021 to retrieve the complete specimen.

The researchers, who are from the University of California, Santa Cruz have confirmed that the tusk — about one metre in length — is from a Columbian mammoth.

The cold, high-pressure environment of the deep sea uniquely preserved the tusk, giving researchers the opportunity to study it in greater detail. CT scans of the specimen will reveal the full three-dimensional internal structure of the tusk and more information about the animal’s history, such as its age.

The team believes that this could be the oldest well-preserved mammoth tusk recovered from this region of North America. Dating of the tusk is still in progress, but researchers have already revealed that the tusk is much more than 100,000 years old. Read more.

Most Milky Way dwarf galaxies are newcomers

Data from the European Space Agency’s Gaia mission has revealed that most of the dwarf galaxies around the Milky Way — which have traditionally been thought of as satellites — actually only arrived in our vicinity in the past few billion years.

The findings rewrite the history of our galaxy.

A dwarf galaxy is a collection of stars, numbering between a thousand and several billion. For decades it has been widely believed that the dwarf galaxies that surround the Milky Way are satellites, meaning that they are caught in orbit around our galaxy, and have been our constant companions for many billions of years.

Researchers have now computed the motions of these dwarf galaxies with unprecedented precision. The team found that the dwarf galaxies are revolving so fast they could not be in orbit around the Milky Way, where interactions with our galaxy and its contents would have sapped their orbital energy and angular momentum. Read more.


Also read: New mineral from deep inside Earth found trapped in a diamond


Arctic Ocean has been warming for longer than thought

Researchers suggest that the Arctic Ocean has been getting warmer since the beginning of the 20th century — decades earlier than records suggest.

The rise in temperature is a result of warmer water flowing into the polar ecosystem from the Atlantic Ocean.

An international group of researchers reconstructed the recent history of ocean warming at the gateway to the Arctic Ocean in a region called the Fram Strait, between Greenland and Svalbard.

Using the chemical signatures found in marine microorganisms, the researchers found that the Arctic Ocean began warming rapidly at the beginning of the last century as warmer and saltier waters flowed in from the Atlantic.

This change preceded the warming documented by modern instrumental measurements. Since 1900, the ocean temperature has risen by approximately 2 degrees Celsius, while sea ice has retreated and salinity has increased.

The study provides the first historical perspective on Atlantification of the Arctic Ocean and reveals a connection with the North Atlantic that is much stronger than previously thought. Read more.

Seismic data gives a glimpse under Martian surface

Using seismic data from the second largest volcanic region on Mars, researchers have had the opportunity to get a peek under the layer of the red planet. The team has found the presence of a shallow sedimentary layer sandwiched between lava flows beneath the planet’s surface.

The team examined the shallow subsurface to around 200 metres in depth. Right beneath the surface, they discovered a layer of sandy material approximately three meters thick, above a 15-metre layer of coarse rocky blocks that were ejected after a meteorite impact and fell back to the surface.

Below these top layers, they identified around 150 metres of basaltic rocks, which are cooled and solidified lava flows. Between these lava flows, starting at a depth of about 30 metres, the team identified an additional layer — 30 to 40 metres thick, with low seismic velocity — suggesting it contains weak sedimentary materials relative to the stronger basalt layers.

The team suggests that the shallower lava flows are about 1.7 billion years old. In contrast, the deeper basalt layer below the sediments were formed much earlier, approximately 3.6 billion years ago, when Mars had widespread volcanic activity. Read more.


Also read: Singhbhum in India could have been first land mass to rise from oceans 3 billion years ago


Bees that consume meat 

Scientists have discovered that a little-known species of tropical bee has evolved an extra tooth for biting flesh and a gut that more closely resembles that of vultures rather than other bees.

Typically, bees don’t eat meat. However, a species of stingless bee in the tropics has evolved the ability to do so. Scientists presume that this is a result of intense competition for nectar.

These are the only bees in the world known to have evolved to use food sources not produced by plants.

Honeybees, bumblebees, and stingless bees have guts that are colonised by the same five core microbes. Unlike humans, whose gut microbes can change with diet, most bee species have retained these same bacteria over 80 million years of evolution.

Given their radical change in food choice, a team of scientists wondered whether the gut bacteria of vulture bees (as they are being referred to by the researchers) differed from those of a typical vegetarian bee.

On analysing the microbiomes of the bees, they found the most extreme changes among exclusive meat-feeders.

The vulture bee microbiome is enriched in acid-loving bacteria — which their vegetarian relatives do not have. But even though they feed on meat, their honey is still sweet and edible, the team noted.

The vulture bees store the meat in special chambers in their hives that are sealed off for two weeks before they access it, and these chambers are separate from where the honey is stored.

The research team is planning to delve further into vulture bee microbiomes, hoping to learn about the genomes of all bacteria as well as fungi and viruses in their bodies. Read more here.

(Edited by Poulomi Banerjee)


Also read: Water and CO molecules found in a galaxy light years away and how black holes gain mass


 

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