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Comment by Dr. Krishna Kumari Challa on January 15, 2022 at 8:23am

Copper-based chemicals may be contributing to ozone depletion

Copper released into the environment from fungicides, brake pads, antifouling paints on boats and other sources may be contributing significantly to stratospheric ozone depletion, according to a new study .

In a paper appearing this week in the journal Nature Communications, UC Berkeley geochemists show that copper in soil and seawater acts as a catalyst to turn organic matter into both methyl bromide and methyl chloride, two potent halocarbon compounds that destroy ozone. Sunlight worsens the situation, producing about 10 times the amount of these methyl halides.

The findings answer, at least in part, a long-standing mystery about the origin of much of the methyl bromide and methyl chloride in the stratosphere. Since the worldwide ban on chlorofluorocarbon (CFC) refrigerants and brominated halons used in fire extinguishers starting in 1989, these methyl halides have become the new dominant sources of ozone-depleting bromine and chlorine in the stratosphere. As the long-lived CFCs and halons slowly disappear from the atmosphere, the role of methyl halides increases.

Yi Jiao et al, Application of copper(II)-based chemicals induces CH3Br and CH3Cl emissions from soil and seawater, Nature Communications (2022). DOI: 10.1038/s41467-021-27779-3

https://phys.org/news/2022-01-copper-based-chemicals-contributing-o...

Comment by Dr. Krishna Kumari Challa on January 15, 2022 at 8:14am

Strong evidence shows Sixth Mass Extinction of global biodiversity in progress

The history of life on Earth has been marked five times by events of mass biodiversity extinction caused by extreme natural phenomena. Today, many experts warn that a Sixth Mass Extinction crisis is underway, this time entirely caused by human activities.

A comprehensive assessment of evidence of this ongoing extinction event was published recently in the journal Biological Reviews by biologists .

Drastically increased rates of species extinctions and declining abundances of many animal and plant populations are well documented, yet some deny that these phenomena amount to mass extinction. This denial is based on a biased view of the crisis which focuses on mammals and birds and ignores invertebrates, which of course constitute the great majority of biodiversity.

By extrapolating from estimates obtained for land snails and slugs, biologists estimated that since the year 1500, Earth could already have lost between 7.5 and 13% of the two million known species on Earth—a staggering 150,000 to 260,000 species.

Including invertebrates was key to confirming that we are indeed witnessing the onset of the Sixth Mass Extinction in Earth's history.

The situation is not the same everywhere, however. Although marine species face significant threats, there is no evidence that the crisis is affecting the oceans to the same extent as the land. On land, island species, such as those of the Hawaiian Islands, are much more affected than continental species. And the rate of extinction of plants seems lower than that of terrestrial animals.

To fight the crisis, various conservation initiatives have been successful for certain charismatic animals. But these initiatives cannot target all species, and they cannot reverse the overall trend of species extinction. Nonetheless, it is essential to continue such efforts, to continue to cultivate a wonder for nature, and to document biodiversity before it disappears.

Robert H. Cowie et al, The Sixth Mass Extinction: fact, fiction or speculation?, Biological Reviews (2022). DOI: 10.1111/brv.12816

https://phys.org/news/2022-01-strong-evidence-sixth-mass-extinction...

Comment by Dr. Krishna Kumari Challa on January 14, 2022 at 10:59am

A mysterious new way of producing oxygen
Researchers have discovered that some microbes that live in the deep sea produce oxygen in a way never seen before. The surprising species, Nitrosopumilus maritimus, uses a common method to generate energy: the oxidation of ammonia to nitrite. But when researchers sealed the microbes in airtight containers, without light or oxygen, they were still somehow able to produce O2. The findings could have implications for everything from detecting the signs of life to determining how bacteria might adapt to a drop in ocean oxygen caused by climate change.

This has only been found previously in NC10 bacteria, which break up nitric oxide into nitrogen and oxygen and use the oxygen to oxidise methane. However, the NC10 bacteria are not known to release oxygen. https://www.chemistryworld.com/news/single-celled-marine-organism-f...

Comment by Dr. Krishna Kumari Challa on January 14, 2022 at 10:53am

How to image atoms

Comment by Dr. Krishna Kumari Challa on January 14, 2022 at 9:58am

Some birds sing the same song for hundreds of thousands of years

Many of the birds that awaken us each morning learn their melodious songs the same way that humans learn a dialect—from parents and neighbours.

But to most biologists, learning songs through mimicry is an uncertain and error-prone process, resulting in slow but inevitable change in song over the years.

A new study by biologists , however, documents songs in East African sunbirds that have remained nearly unchanged for more than 500,000 years, and perhaps for as long as 1 million years, making the songs nearly indistinguishable from those of relatives from which they've long been separated.

The amazingly static nature of their songs may be due to a lack of change in these birds' environments, which are stable mountain forests—so-called sky islands—isolated from other sky island populations of the same or similar species for tens of thousands to millions of years. The coloration of the birds' feathers has changed little, as well, making their plumage nearly indistinguishable from each other, even though some are separate, but closely related, species.

Jay P. McEntee et al, Punctuated evolution in the learned songs of African sunbirds, Proceedings of the Royal Society B: Biological Sciences (2021). DOI: 10.1098/rspb.2021.2062

https://phys.org/news/2022-01-birds-song-hundreds-thousands-years.h...

Comment by Dr. Krishna Kumari Challa on January 14, 2022 at 9:46am

Lost birds and mammals spell doom for some plants

In one of the first studies of its kind, researchers have gauged how biodiversity loss of birds and mammals will impact plants' chances of adapting to human-induced climate warming.

More than half of plant species rely on animals to disperse their seeds. In a study  researchers showed the ability of animal-dispersed plants to keep pace with climate change has been reduced by 60% due to the loss of mammals and birds that help such plants adapt to environmental change.

As climate changes, many plant species must move to a more suitable environment. Plants that rely on seed dispersers can face extinction if there are too few animals to move their seeds far enough to keep pace with changing conditions.

If there are no animals available to eat their fruits or carry away their nuts, animal-dispersed plants aren't moving very far. And many plants people rely on, both economically and ecologically, are reliant on seed-dispersing birds and mammals.

The study showed seed-dispersal losses were especially severe in temperate regions across North America, Europe, South America and Australia. If endangered species go extinct, tropical regions in South America, Africa and Southeast Asia would be most affected.

Evan C. Fricke, The effects of defaunation on plants' capacity to track climate change, Science (2022). DOI: 10.1126/science.abk3510. www.science.org/doi/10.1126/science.abk3510

https://phys.org/news/2022-01-lost-birds-mammals-doom.html?utm_sour...

Comment by Dr. Krishna Kumari Challa on January 14, 2022 at 9:37am

Researchers propose new explanation for Moon's half-century magnetic mystery

Rocks returned to Earth during NASA's Apollo program from 1968 to 1972 have provided volumes of information about the Moon's history, but they've also been the source of an enduring mystery. Analysis of the rocks revealed that some seemed to have formed in the presence of a strong magnetic field—one that rivaled Earth's in strength. But it wasn't clear how a Moon-sized body could have generated a magnetic field that strong.

Now, new research proposes a new explanation for the Moon's magnetic mystery. The study, published in Nature Astronomy, shows that giant rock formations sinking through the Moon's mantle could have produced the kind of interior convection that generates strong magnetic fields. The processes could have produced intermittently strong magnetic fields for the first billion years of the Moon's history, the researchers say.

The Moon lacks a magnetic field today, and models of its core suggest that it was probably too small and lacked the convective force to have ever produced a continuously strong magnetic field. In order for a core to have a strong convective churn, it needs to dissipate a lot of heat. In the case of the early Moon, researchers say, the mantle surrounding the core wasn't much cooler than the core itself. Because the core's heat didn't have anywhere to go, there wasn't much convection in the core. But this new study shows how sinking rocks could have provided intermittent convective boosts.

The story of these sinking stones starts a few million years after the Moon's formation. Very early in its history, the Moon is thought to have been covered by an ocean of molten rock. As the vast magma ocean began to cool and solidify, minerals like olivine and pyroxene that were denser than the liquid magma sank to the bottom, while less dense minerals like anorthosite floated to form the crust. The remaining liquid magma was rich in titanium as well as heat-producing elements like thorium, uranium and potassium, so it took a bit longer to solidify. When this titanium layer finally crystallized just beneath the crust, it was denser than the earlier-solidifying minerals below it. Over time, the titanium formations sank through the less-dense mantle rock underneath, a process known as gravitational overturn.

There could have been as many as 100 of these downwelling events over the Moon's first billion years of existence, the researchers say, and each one could have produced a strong magnetic field lasting a century or so.

Alexander Evans, An episodic high-intensity lunar core dynamo, Nature Astronomy (2022). DOI: 10.1038/s41550-021-01574-y. www.nature.com/articles/s41550-021-01574-y

https://phys.org/news/2022-01-explanation-moon-half-century-magneti...

Comment by Dr. Krishna Kumari Challa on January 13, 2022 at 12:56pm

Antibody Cocktail Therapy Explained

Comment by Dr. Krishna Kumari Challa on January 13, 2022 at 12:28pm

The scientists found that the way DNA was wrapped around different types of proteins was a good predictor of whether a gene would mutate or not. It means we can predict which genes are more likely to mutate than others and it gives us a good idea of what's going on.

The findings add a surprising twist to Charles Darwin's theory of evolution by natural selection because it reveals that the plant has evolved to protect its genes from mutation to ensure survival.

The plant has evolved a way to protect its most important places from mutation. This is exciting because we could even use these discoveries to think about how to protect human genes from mutation.

Knowing why some regions of the genome mutate more than others could help breeders who rely on genetic variation to develop better crops. Scientists could also use the information to better predict or develop new treatments for diseases like cancer that are caused by mutation.

Detlef Weigel, Mutation bias reflects natural selection in Arabidopsis thaliana, Nature (2022). DOI: 10.1038/s41586-021-04269-6. www.nature.com/articles/s41586-021-04269-6

https://phys.org/news/2022-01-evolutionary-theory-dna-mutations-ran...

Comment by Dr. Krishna Kumari Challa on January 13, 2022 at 12:27pm

Study challenges evolutionary theory that DNA mutations are random

A simple roadside weed may hold the key to understanding and predicting DNA mutation, according to new research.

The findings, published January 12 in the journal Nature, radically change our understanding of evolution and could one day help researchers breed better crops or even help humans fight cancer.

Mutations occur when DNA is damaged and left unrepaired, creating a new variation. The scientists wanted to know if mutation was purely random or something deeper. What they found was unexpected.

Scientists thought of mutation as basically random across the genome till now. It turns out that mutation is very non-random and it's non-random in a way that benefits the plant. It's a totally new way of thinking about mutation.

Researchers spent three years sequencing the DNA of hundreds of Arabidopsis thaliana, or thale cress, a small, flowering weed considered the "lab rat among plants" because of its relatively small genome comprising around 120 million base pairs. Humans, by comparison, have roughly 3 billion base pairs. It's a model organism for genetics. 

Researchers grew specimens in a protected lab environment, which allowed plants with defects that may not have survived in nature be able to survive in a controlled space.

Sequencing of those hundreds of Arabidopsis thaliana plants revealed more than 1 million mutations. Within those mutations a nonrandom pattern was revealed, counter to what was expected.

Instead of randomness scientists found patches of the genome with low mutation rates. In those patches, they were surprised to discover an over-representation of essential genes, such as those involved in cell growth and gene expression. 

These are the really important regions of the genome. The areas that are the most biologically important are the ones being protected from mutation.

The areas are also sensitive to the harmful effects of new mutations. DNA damage repair seems therefore to be particularly effective in these regions.

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