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“Lead pollution in Arctic ice shows economic impact of wars and plagues for past 1500 years - EurekAlert” plus 2 more

“Lead pollution in Arctic ice shows economic impact of wars and plagues for past 1500 years - EurekAlert” plus 2 more

Lead pollution in Arctic ice shows economic impact of wars and plagues for past 1500 years - EurekAlert

Posted: 08 Jul 2019 12:03 PM PDT

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IMAGE: Joe McConnell, Ph.D, the study's lead author, and Nathan Chellman, a doctoral student at DRI and coauthor on the study, examine an ice core in DRI's Ultra-Trace Ice Core Chemistry... view more 

Credit: DRI

RENO, Nev. (July 8, 2019) - How did events like the Black Death plague impact the economy of Medieval Europe? Particles of lead trapped deep in Arctic ice can tell us.

Commercial and industrial processes have emitted lead into the atmosphere for thousands of years, from the mining and smelting of silver ores to make currency for ancient Rome to the burning of fossil fuels today. This lead pollution travels on wind currents through the atmosphere, eventually settling on places like the ice sheet in Greenland and other parts of the Arctic.

Because of lead's connection to precious metals like silver and the fact that natural lead levels in the environment are very low, scientists have found that lead deposits in layers of Arctic ice are a sensitive indicator of overall economic activity throughout history.

In a new study published in the Proceedings of the National Academy of Sciences, researchers from the Desert Research Institute (DRI), the University of Oxford, NILU - Norwegian Institute for Air Research, the University of Copenhagen, the University of Rochester, the Alfred Wegener Institute for Polar and Marine Research used thirteen Arctic ice cores from Greenland and the Russian Arctic to measure, date, and analyze lead emissions captured in the ice from 500 to 2010 CE, a period of time that extended from the Middle Ages through the Modern Period to the present.

This work builds on a study published by some of the same researchers in 2018, which showed how lead pollution in a single ice core from Greenland tracked the ups and downs of the European economy between 1100 BCE and 800 CE, a period which included the Greek and Roman empires.

"We have extended our earlier record through the Middle Ages and Modern Period to the present," explained Joe McConnell, Ph.D., lead author on the study and Director of DRI's Ultra-Trace Ice Core Chemistry Laboratory in Reno, Nevada. "Using an array of thirteen ice cores instead of just one, this new study shows that prior to the Industrial Revolution, lead pollution was pervasive and surprisingly similar across a large swath of the Arctic and undoubtedly the result of European emissions. The ice-core array provides with amazing detail a continuous record of European - and later North American - industrial emissions during the past 1500 years."

"Developing and interpreting such an extensive array of Arctic ice-core records would have been impossible without international collaboration," McConnell added.

The research team found that increases in lead concentration in the ice cores track closely with periods of expansion in Europe, the advent of new technologies, and economic prosperity. Decreases in lead, on the other hand, paralleled climate disruptions, wars, plagues, and famines.

"Sustained increases in lead pollution during the Early and High Middle Ages (about 800 to 1300 CE), for example, indicate widespread economic growth, particularly in central Europe as new mining areas were discovered in places like the German Harz and Erzgebirge Mountains, "McConnell noted. "Lead pollution in the ice core records declined during the Late Middle Ages and Early Modern Period (about 1300 to 1680 Ce) when plague devastated those regions, however, indicating that economic activity stalled."

Even with ups and downs over time due to events such as plagues, the study shows that increases in lead pollution in the Arctic during the past 1500 years have been exponential.

"We found an overall 250 to 300-fold increase in Arctic lead pollution from the start of the Middle Ages in 500 CE to 1970s," explained Nathan Chellman, a doctoral student at DRI and coauthor on the study. "Since the passage of pollution abatement policies, including the 1970 Clean Air Act in the United States, lead pollution in Arctic ice has declined more than 80 percent."

"Still, lead levels are about 60 times higher today than they were at the beginning of the Middle Ages," Chellman added.

This study included an array of ice cores and the research team used state-of-the-art atmospheric modeling to determine the relative sensitivity of different ice-core sites in the Arctic to lead emissions.

"Modeling shows that the core from the Russian Arctic is more sensitive to European emissions, particularly from eastern parts of Europe, than cores from Greenland," explained Andreas Stohl, Ph.D., atmospheric scientist at NILU and coauthor on the study. "This is why we found consistently higher levels of lead pollution in the Russian Arctic core and more rapid increases during the Early and High Middle Ages as mining operations shifted north and east from the Iberian Peninsula to Great Britain and Germany."

The combination of expertise on this study is unique, continuing a collaboration between researchers in fields as different as ice-core chemistry and economic history. These results, the team argues, are a testament to the benefits of interdisciplinary collaboration.

"What we're finding is interesting not just to environmental scientists who want to understand how human activity has altered the environment," said Andrew Wilson, Ph.D., Professor of the Archaeology of the Roman Empire at Oxford and co-author on the study. "These ice-core records also are helping historians to understand and quantify the ways that societies and their economies have responded to external forces such as climate disruptions, plagues, or political unrest."

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Collection, analysis, and interpretation of the ice cores used in this study were supported by the U.S. National Science Foundation, NASA, the John Fell Oxford University Press Research Fund and All Souls College, Oxford, the German Ministry of Education and Research, the German Research Foundation, and the Desert Research Institute.

The Desert Research Institute (DRI) is a recognized world leader in basic and applied interdisciplinary research. Committed to scientific excellence and integrity, DRI faculty, students, and staff have developed scientific knowledge and innovative technologies in research projects around the globe. Since 1959, DRI's research has advanced scientific knowledge, supported Nevada's diversifying economy, provided science-based educational opportunities, and informed policymakers, business leaders, and community members. With campuses in Reno and Las Vegas, DRI is one of eight institutions in the Nevada System of Higher Education. Learn more at http://www.dri.edu, and connect with us on social media on Facebook, Instagram, and Twitter.

#JusticeForElijah Trends After Man Brutally Stabs Black Teen to Death for Listening to Rap Music - Newsweek

Posted: 08 Jul 2019 06:42 AM PDT

Thousands have reacted to reports of a black teenager being allegedly murdered for listening to rap music in Arizona, with the hashtag #JusticeForElijah trending on Twitter.

Michael Adams, 27, has been charged with the first-degree murder of 17-year-old Elijah Al-Amin. The teenager died from his injuries after his throat was slit at around 1:42 a.m. at a Circle K store in Peoria on July 4.

According to court documents, seen by AZ Central, Adams told police that he decided to kill the teenager because he was playing rap music in his vehicle, which made him feel unsafe.

Adams admitted he was not provoked or threatened by the teenager prior to the alleged attack, but decided to be "proactive rather than reactive," as he said people who listen to rap music are a threat to him and the community.

According to Arizona Department of Corrections, Adams had just been released from the Arizona State Prison Complex in Yuma two days before he allegedly killed Al-Amin.

After the murder charges were brought forward, Jacie Cotterell, Adams's lawyer, said her client was "set up for failure," because of inabilities to give him access to mental health services following his release from prison.

"To be specific, he was given resources, he wasn't given means to get to those resources," Cotterell told AZ Central.

Speaking to Fox 10, Cotterell argued that Adams should not have been sent to jail in the first place.

"It's too easy as a society to shake our head and say well, they committed a crime, it's too bad, we have jails for that when really, what they need is treatment. They need a bed instead of a cell," she said.

In a statement, Bill Lamoreaux, a spokesman for Arizona Department of Corrections, said that Adams "was not designated seriously mentally ill" following his release.

"The tragic death is terrible, and Mr. Adams will have to answer for his alleged actions," he added.

Twitter users have been paying their respects for the 17-year-old while questioning whether mental health issues would be brought up if the suspect and the victim's races were switched.

In a statement, Peoria Police Chief Art Miller said: "We are committed to detailed and complete investigations and we will determine why this violent act occurred. On behalf of the men and women of the Peoria Police Department, we extend our deepest condolences to the family and friends of the victim."

Adams was booked into a Maricopa County jail on suspicion of first-degree premeditated murder and is currently being held on a $1 million bond. He is due to appear next in court on July 15.

Michael Adams
Michael Adams has been charged with the first-degree murder of 17-year-old Elijah Al-Amin. Peoria Police

Black hole brings down curtain on jellyfish galaxy's star turn - Science Daily

Posted: 02 Jul 2019 03:52 PM PDT

The role of an excited black hole in the death of an exotic 'jellyfish' galaxy will be presented today (3 July) by Callum Bellhouse of the University of Birmingham at the RAS National Astronomy Meeting in Lancaster. The supermassive black hole at the centre of jellyfish galaxy JO201 is stripping away gas and throwing it out into space, accelerating suppression of star formation and effectively 'killing' the galaxy.

Jellyfish galaxies are spectacular objects that undergo a dramatic process of transformation as they plunge through the dense core of a galaxy cluster at supersonic speeds. External drag forces tear away the galaxy's gas, in a process known as ram-pressure stripping, leaving extended tentacles of trailing material.

The fate of JO201 has been revealed as part of a study of 114 jellyfish galaxies by the GASP (GAs Stripping Phenomena) collaboration, an international team of researchers led by Dr Bianca Poggianti.

To explore the structure of the jellyfish galaxies in 3D and estimate the timescales of their transformation, Bellhouse has createdinteractive models that can also be experienced in virtual reality.

The study shows that JO201, originally a large spiral galaxy, has been diving through the massive cluster Abell 85 at supersonic speeds for around a billion years. As the jellyfish galaxy is travelling along the line of sight, its tentacles appear foreshortened in the model, but the team estimates that they trail 94 kiloparsecs behind JO201 -- about three times the diameter of our Milky Way.

"A galaxy sustains itself by constantly forming new stars from gas, so understanding how gas flows into and out of a galaxy helps us learn how it evolves. The example of JO201 shows how the balance tips towards then away from star-formation as it plunges through the galaxy cluster and faces increasingly extreme stripping of its gas," said Bellhouse.

JO201's transformation into a jellyfish galaxy has caused a brief increase in star formation due to the ram-pressure stripping process. Compressed clouds of gas have collapsed and formed a ring of stars in the disk of the galaxy. Dense knots in tentacles have condensed like rainclouds to begin forming new stars in the galaxy's wake.

However, the over the last few hundred million years, the black hole appears to have ripped away gas to leave a large void around the centre of the galaxy disc. The team believes that the ram-pressure stripping may have funnelled gas into the central parts of the galaxy, where it has provoked the black hole into blasting out material and creating a shock-wave that has left a cavity behind.

"An important balancing act occurs between processes which either boost or diminish the star formation rate in jellyfish galaxies. In the case of JO201, the central black hole becomes excited by the ram-pressure stripping and starts to throw out gas. This means that the galaxy is being hollowed out from the inside, as well as torn away from the outside," said Bellhouse.

"JO201 is, so far, a unique example of a supermassive black hole and ram-pressure stripping in quenching star formation in a jellyfish galaxy. Studying these curious objects gives us an insight into the complex processes that galaxies experience," said Bellhouse.

Story Source:

Materials provided by Royal Astronomical Society. Note: Content may be edited for style and length.
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