New Delhi: Scientists have predicted that a major current system of the Atlantic Ocean might collapse in the coming decades. A paper published in Nature journal on 25 July looked at the Atlantic meridional overturning circulation (AMOC), which is significant for the Earth’s climate system. It is responsible for redistributing heat and regulating climate in the entire North Atlantic region.
The AMOC is essentially an ocean circulation pattern that transports warm water from the tropics to the North Atlantic regions and sends colder water back south. With this, vital nutrients, marine organisms, and resources are also transported.
The AMOC has long been a ‘tipping element’ in the Earth’s system, meaning it is vulnerable enough to collapse or ‘tip over’ with small disturbances. In their study, Peter Ditlevsen and Susanne Ditlevsen looked at data collected on the AMOC over a period of time. Using this data, they attempted to predict when, if at all, a change would occur in the circulation pattern.
There have been bigger fluctuations in the water temperature in the North Atlantic, and these fluctuations have taken longer to return to normal. Their findings suggest that there is a critical point of change that the circulation pattern is approaching, and a mathematical model devised by them shows the pattern could collapse as soon as 2025.
The study contradicts the recent UN Intergovernmental Panel on Climate Change report which states that the AMOC is not in danger of collapsing this century. However, there have been concerns about the collapse of this system for a while now, especially since global warming has led to faster melting of ice caps and disturbed the balance of the system. Read More
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How diamonds erupt
A new study has uncovered how diamonds erupt to the earth’s surface through explosions. Over a period of time, a certain kind of magma called kimberlite erupts onto the Earth. These kimberlites contain diamonds that blast from the depths of the Earth onto the surface. Scientists have wondered how these blasts occur, since diamonds form deep inside the Earth’s surface.
The study published in Nature has found that the diamond-laden kimberlite eruptions occur due to breakups in the Earth’s continental plates. The study found that most of the kimberlite eruptions in the past billion years have happened 30 million years after the continental breakup. Earth’s continental plates break apart and come together over a long time period, starting 175 million years ago with the break-up of supercontinent Pangea.
When the continental plates break apart, they cause shifts and bends in the lithosphere, which is the Earth’s surface. Due to this, hot magma rushes towards the lower part of the lithosphere. This magma has been studied and is very similar to the kimberlite rocks that then erupt to the surface from the lithosphere. Read More
7 generations of Neolithic family
Archaeologists have been able to trace a prehistoric family back seven generations using DNA. Published in Nature on 26 July, an ancient genomics study looked at the social and kinship organisation structures of a Neolithic community almost 6,500 years ago.
The team of researchers analysed 94 of the 128 skeletal remains found in a French burial site called Gurgy ‘les Noisats’. It is the biggest burial site in its region and has been dated to the 5th millennium BC.
By analysing these skeletal remains found close to each other, scientists discovered that almost two-thirds of them were related. The communities they studied were connected by two main lineages, going back to seven generations.
Overall, these discoveries helped the scientists piece together social and kinship dynamics of Neolithic families and communities. Read More
Asymptomatic Covid patients
Why did some people show no symptoms of the novel coronavirus? The answer might lie in a certain genetic mutation. A study published in Nature shows a mutation in the human leukocyte antigen (HLA) gene that could be responsible for an asymptomatic response to SARS-CoV-2 infection.
The HLA gene is important in the functioning of the immune system. It is also a highly variable gene and has been linked to diseases such as HIV and hepatitis. The study looked at almost 30,000 individuals who had high-quality genetic data available. From this group, they got 1,428 unvaccinated people who tested positive for the virus and reported no symptoms. When they analysed this group of people, the researchers found a strong link between the HLA-B*15:01 variant and lack of Covid symptoms.
Probing further, the scientists postulated this could be because the HLA-B*15:01 variant has pre-existing T-cell immunity. T cells are a certain kind of immunity cells that recognise and attack viruses. According to the study, this is because the T cells have a memory of fighting similar virus cells and react accordingly. Read More
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Moon has a solid core
A study by scientists from the University of Cote d’Azur and Sorbonne University has discovered more evidence that supports the idea that the Moon has a solid inner core. The study had two main aims: to determine the composition of the moon’s core (viscous outer core and solid inner core) and to understand the moon’s proposed mantle overturn phenomenon. The researchers in the study used data from the Apollo 11 mission to the Moon.
Through this data, they were able to determine that a region between the mantle and the core of the moon exists where there is a decrease in seismic wave velocity. They made simulations showing all possible inner structures that the Moon could have. They concluded that a solid inner core and a low viscosity zone is the only possible scenario, taking into account thermodynamic constraints and the Moon’s tidal deformations.
Apart from this, they also studied the phenomenon of lunar mantle overturn, which proposes that the Moon’s mantle undergoes overturns just like tectonic plate shifts on the earth’s surface. The conclusions stated earlier, that is, the presence of a low-viscosity zone and a solid inner core at the same time, provided scientists with evidence supporting mantle overturn in the Moon. Read More
(Edited by Smriti Sinha)
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