6.26.24
Researchers have discovered a clue in Italian limestone that helps explain a mass extinction of marine life millions of years ago, and may provide warnings about how oxygen depletion and climate change could impact today’s oceans.
Mariano Remírez
“This event, and events like it, are the best analogs we have in Earth’s past for what is to come in the next decades and centuries,” said Michael A. Kipp, an earth and climate science assistant professor at Duke University. Kipp co-authored a study published June 24 in the PNAS that measures oxygen loss in oceans leading to the extinction of marine species 183 million years ago.
During the Jurassic Period, when marine reptiles like ichthyosaurs and plesiosaurs thrived, volcanic activity in modern South Africa released an estimated 20,500 gigatons of carbon dioxide (CO2) over 500,000 years. This heated the oceans, causing them to lose oxygen.
The result was the suffocation and mass extinction of marine species.
“It’s an analog, but not a perfect one, to predict what will happen to future oxygen loss in oceans from human-made carbon emissions, and the impact that loss will have on marine ecosystems and biodiversity,” said co-author Mariano Remírez, an assistant research professor at George Mason University.
Studying limestone sediment that carries chemicals dating back to the time of the volcanic outburst, researchers were able to estimate the change in oxygen levels in ancient oceans. At one point, oxygen was completely depleted in up to 8% of the ancient global seafloor, an area roughly three times the size of the United States.
Since the Industrial Revolution began in the 18th and 19th centuries, human activity has released CO2 emissions equivalent to 12% of what was released during the Jurassic volcanism.
But Kipp said that today’s rapid rate of atmospheric CO2 release is unprecedented in history, making it hard to predict when another mass extinction might occur or how severe it might be.
“We just don’t have anything this severe,” Kipp said. “We go to the most rapid CO2-emitting events we can in history, and they’re still not rapid enough to be a perfect comparison to what we’re going through today. We’re perturbing the system faster than ever before.”
“We have at least quantified the marine oxygen loss during this event, which will help constrain our predictions of what will happen in the future,” Kipp said.
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Younger than most other prestigious U.S. research universities, Duke University consistently ranks among the very best. Duke’s graduate and professional schools — in business, divinity, engineering, the environment, law, medicine, nursing and public policy — are among the leaders in their fields. Duke’s home campus is situated on nearly 9,000 acres in Durham, N.C, a city of more than 200,000 people. Duke also is active internationally through the Duke-NUS Graduate Medical School in Singapore, Duke Kunshan University in China and numerous research and education programs across the globe. More than 75 percent of Duke students pursue service-learning opportunities in Durham and around the world through “DukeEngage” and other programs that advance the university’s mission of “knowledge in service to society.”
Duke University is a private research university in Durham, North Carolina. Founded by Methodists and Quakers in the present-day town of Trinity in 1838, the school moved to Durham in 1892. In 1924, tobacco and electric power industrialist James Buchanan Duke established The Duke Endowment and the institution changed its name to honor his deceased father, Washington Duke.
The campus spans over 8,600 acres (3,500 hectares) on three contiguous sub-campuses in Durham, and a marine lab in Beaufort. The West Campus—designed largely by architect Julian Abele, an African American architect who graduated first in his class at the University of Pennsylvania School of Design —incorporates Gothic architecture with the 210-foot (64-meter) Duke Chapel at the campus’ center and highest point of elevation, is adjacent to the Medical Center. East Campus, 1.5 miles (2.4 kilometers) away, home to all first-years, contains Georgian-style architecture. The university administers two concurrent schools in Asia, Duke-NUS Medical School in Singapore (established in 2005) and Duke Kunshan University in Kunshan, China (established in 2013).
Duke is ranked among the top universities in the United States. The undergraduate admissions are among the most selective in the country, with an overall acceptance rate of about 5.5%. Duke spends more than $1 billion per year on research, making it one of the ten largest research universities in the United States. More than a dozen faculty regularly appear on annual lists of the world’s most-cited researchers. Nobel laureates and Turing Award winners have been affiliated with the university. Duke alumni also include Rhodes Scholars, Churchill Scholars, Schwarzman Scholars, and Mitchell Scholars. The university has produced one of the highest number of Churchill Scholars of any university (behind Princeton University and Harvard University) and high numbers of Rhodes, Marshall, Truman, Goldwater, and Udall Scholars. Duke is the alma mater of presidents of the United States and many living billionaires.
Duke is the second-largest private employer in North Carolina, with more than 39,000 employees. The university has been ranked as an excellent employer by several publications.
Research
Duke’s research expenditures are in the billions of dollars, very high in the U.S. Duke receives millions in funding from the National Institutes of Health. Duke is classified among “R1: Doctoral Universities – Very high research activity”.
Throughout the school’s history, Duke researchers have made breakthroughs, including the biomedical engineering department’s development of the world’s first real-time, three-dimensional ultrasound diagnostic system and the first engineered blood vessels and stents. In 2015, Paul Modrich shared the Nobel Prize in Chemistry. In 2012, Robert Lefkowitz along with Brian Kobilka, who is also a former affiliate, shared the Nobel Prize in chemistry for their work on cell surface receptors. Duke has pioneered studies involving nonlinear dynamics, chaos, and complex systems in physics.
In May 2006 Duke researchers mapped the final human chromosome, which made world news as it marked the completion of the Human Genome Project. Reports of Duke researchers’ involvement in new AIDS vaccine research surfaced in June 2006. The biology department combines two historically strong programs in botany and zoology, while the divinity school includes leading theologians. The graduate program in literature boasts several internationally renowned figures, while philosophers contribute to Duke’s ranking as the nation’s best program in philosophy of biology, according to the Philosophical Gourmet Report.