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Study Suggests A Supernova Exploded Near Earth About 2.5 Million Years Ago, Possibly Causing An Extinction Event

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Supernovas are amazingly bright explosions of massive stars at the end of their lives. During the gravitational collapse, the outer layers of the star are pushed away, and chemical elements formed inside the dying star are released into space. This cosmic dust rains down onto the Earth continuously, eventually becoming part of sediments deposited in the sea.

Research published in the journal Physical Review Letters used the concentrations of elements formed in an exploding star and preserved in oceanic sediments to hypothesize that a supernova exploded near Earth just 2.5 million years ago.

The authors, led by Dr. Gunther Korschinek from the Technical University of Munich, focused their study on ferromanganese crusts collected in the Pacific Ocean. Ferromanganese crusts form on the bottom of the ocean by layers of iron- and manganese-oxides precipitating out of seawater. The studied samples started to grow some 20 million years ago at depths ranging from 5,200 feet to 3.18 miles (approximately 1.600 to 5.120 meters). The researchers measured the concentrations of iron-60 and manganese-53 isotopes in the hardened crust. They differ from Earth’s most common form of the elements by their varying number of neutrons in the atomic nucleus. Both isotopes are synthesized in large stars shortly before supernova explosions and are unstable, decaying completely after 4 to 15 million years. Their presence in sediment samples is evidence for Earth passing through a cloud of cosmic dust generated by an exploding star in – geologically speaking – recent times.

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‘Real and imminent’ extinction risk to whales

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Humpback whale
A humpback whale jumps to the surface of the Pacific Ocean

More than 350 scientists and conservationists from 40 countries have signed a letter calling for global action to protect whales, dolphins and porpoises from extinction.

They say more than half of all species are of conservation concern, with two on the “knife-edge” of extinction.

Lack of action over polluted and over-exploited seas means that many will be declared extinct within our lifetimes, the letter says.

Even large iconic whales are not safe.

“Let this be a historic moment when realising that whales are in danger sparks a powerful wave of action from everyone: regulators, scientists, politicians and the public to save our oceans,” said Mark Simmonds.

The visiting research fellow at the University of Bristol, UK, and senior marine scientist with Humane Society International, has coordinated the letter, which has been signed by experts across the world.

Growing threats

“Save the whales” was a familiar green slogan in the 1970s and 1980s, part of a movement that helped bring an end to commercial whaling.

While stricken populations in most parts of the world have had a chance to recover from organised hunting, they are now facing myriad threats from human actions, including plastic pollution, loss of habitat and prey, climate change and collisions with ships.

By far the biggest threat is becoming accidently captured in fishing equipment and nets, which kills an estimated 300,000 whales, dolphins and porpoises a year.

Rally in Mexico to draw attention to the vaquita
Rally in Mexico to draw attention to the vaquita

Hundreds of scientists have expressed the same concern – that we are moving closer to a number of preventable extinctions. And unless we act now, future generations will be denied the chance to experience these intelligent social and inspiring creatures.

They point to the decline of the North Atlantic right

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The Battle To Save The World’s Rarest Species From Extinction Following Mauritius Oil Spill

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On Monday September 24, at a virtual meeting hosted by the UN Headquarters in New York, 60 world leaders signed a ‘Leaders Pledge for Nature’ to stop the loss of biodiversity. Heads of State from France, Germany, UK, Netherlands, Panama signed.

Noticeably, the embattled political leaders from Japan and Mauritius were not signatories.

The Leaders Pledge in New York was part of an important UN Summit to avoid the world heading into a major period of biodiversity collapse, as planet Earth grapples with the highest extinction rates since homo sapiens became a distinct species, in what has been called the Sixth Mass Extinction. Rather than being caused by colliding asteroids or other natural phenomenon, this new age of extinction is being caused by man.

The front lines of this extinction battle is happening live on the Indian Ocean island of Mauritius, which is still battling the effects of a major oil spill.

Effects of oil spill disrupting entire island nation

Two months on from the major shipping incident in the Indian Ocean, islanders on Mauritius are still reeling from its effects.  Life is far from returning to normal.

The large Japanese bulk carrier, the Wakashio, hit an important barrier coral reef in the South East of the country, and started spilling heavy ship engine fuel into the pristine coral lagoon and into a network of historic and unique biodiversity sites.

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Sentinels of ocean acidification impacts survived Earth’s last mass extinction

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Sentinels of ocean acidification impacts survived Earth's last mass extinction
Several species of planktonic gastropods, including five sea butterflies (shelled) and two sea angels (naked). Credit: Katja Peijnenburg, Erica Goetze, Deborah Wall-Palmer, Lisette Mekkes.

Two groups of tiny, delicate marine organisms, sea butterflies and sea angels, were found to be surprisingly resilient—having survived dramatic global climate change and Earth’s most recent mass extinction event 66 million years ago, according to research published this week in the Proceedings of the National Academy of Sciences led by Katja Peijnenburg from Naturalis Biodiversity Center in the Netherlands.


Sea butterflies and sea angels are pteropods, abundant, floating snails that spend their entire lives in the open ocean. A remarkable example of adaptation to life in the open ocean, these mesmerizing animals can have thin shells and a snail foot transformed into two wing-like structures that enable them to ‘fly’ through the water.

Sea butterflies have been a focus for global change research because they make their shells of aragonite, a form of calcium carbonate that is 50 percent more soluble than calcite, which other important open ocean organisms use to construct their shells. As their shells are susceptible to dissolving in more acidified ocean water, pteropods have been called “canaries in the coal mine,” or sentinel species that signal the impact of ocean acidification.

With some pteropods having thin shells and others having only partial or absent shells, such as the sea angels, their fossil record is patchy. Abundant pteropod fossils are only known from 56 million years ago onward and mostly represent the fully-shelled sea butterflies. These observations led to the notion that evolutionarily, pteropods are a relatively recent group of gastropods.

Sentinels of ocean acidification impacts survived Earth's last mass extinction
Authors Katja Peijnenburg (left) and Erica Goetze (right) at work collecting zooplankton on the AMT22 cruise. Credit: Katja Peijnenburg and Erica Goetze

An international team of researchers sampled 21 pteropod species