DEC 21, 2020 7:49 AM PST

Strontium isotope abundances shed light on early ocean acidification

Scientists from Northwestern have published new findings on the factors that triggered the oceanic anoxic event (OAE) 1a in the Early Cretaceous Period about120 million years ago. The unprecedented study, reported in the journal Geology, used stable strontium isotope measurements in nannoplankton fossils in order to analyze ancient ocean anoxic events.

"We go back in time to study greenhouse periods because Earth is headed toward another greenhouse period now," said first author Jiuyuan Wang. "The only way to look into the future is to understand the past."

A family of marine nannoplankton went extinct during the OAE1a, so measuring the calcium and strontium isotope abundances in their fossils offers a glimpse into that past. To do so, Wang, along with Northwestern professors of earth and planetary sciences Andrew Jacobson, Bradley Sageman and Matthew Hurtgen, explored a 1,600-meter-long sediment core taken from the mid-Pacific Mountains.

They parsed through the sediment in order to detect calcium carbonates, which would allow them to understand what the earth’s climate was like during the Early Cretaceous. But because calcium carbonates have their limitations, the team also analyzed stable isotopes of strontium to get a clearer idea of what was going on.

"Calcium isotope data can be interpreted in a variety of ways," Jacobson said. "Our study exploits observations that calcium and strontium isotopes behave similarly during calcium carbonate formation, but not during alteration that occurs upon burial. In this study, the calcium-strontium isotope 'multi-proxy' provides strong evidence that the signals are 'primary' and relate to the chemistry of seawater during OAE1a."

"Stable strontium isotopes are less likely to undergo physical or chemical alteration over time," Wang added. "Calcium isotopes, on the other hand, can be easily altered under certain conditions."

Photo: Pixabay

The researchers concluded that the long-term eruptions (read: 7 million years) of the Ontong Java Plateau large igneous province (LIP) released tons of carbon dioxide into the atmosphere and ultimately creating the conditions for OAE1a. "There is a direct link between ocean acidification and atmospheric CO2 levels," Jacobson said. "Our study provides key evidence linking eruption of the Ontong Java Plateau LIP to ocean acidification. This is something people expected should be the case based on clues from the fossil record, but geochemical data were lacking."

This geochemical data will help us understand how our oceans will continue to change during the greenhouse period that we are currently experiencing. The authors warn that though the planet has experienced significant greenhouse warming before, these past periods occurred over tens of thousands to millions of years, not less than 200 years, as is our current situation.

Sources: Geology, Science Daily

About the Author
BA Environmental Studies
Kathryn is a curious world-traveller interested in the intersection between nature, culture, history, and people. She has worked for environmental education non-profits and is a Spanish/English interpreter.
You May Also Like
AUG 09, 2022
Space & Astronomy
The Square Kilometer Array: Soon to be the World's Biggest Radio Telescope
AUG 09, 2022
The Square Kilometer Array: Soon to be the World's Biggest Radio Telescope
The Square Kilometer Array Observatory (SKAO) will soon be the largest radio telescope in the world. Construction on the ...
AUG 11, 2022
Cannabis Sciences
How To Eliminate the Smell of Cannabis
AUG 11, 2022
How To Eliminate the Smell of Cannabis
Want to know how to get rid of the lingering odor of cannabis? Here's some tips.
AUG 17, 2022
Technology
Artificial Intelligence Teaches Microrobots how to Swim
AUG 17, 2022
Artificial Intelligence Teaches Microrobots how to Swim
In a recent study published in Communications Physics, a collaborative team of researchers from Santa Clara University, ...
SEP 16, 2022
Genetics & Genomics
Grad Student Highlights: Shannon Barry (Florida Institute of Technology)
SEP 16, 2022
Grad Student Highlights: Shannon Barry (Florida Institute of Technology)
This interview series is focused on the graduate student experience across all STEM fields that allows them to get their ...
SEP 30, 2022
Earth & The Environment
Ancient Mass Extinctions Likely from Volcanic Activity
SEP 30, 2022
Ancient Mass Extinctions Likely from Volcanic Activity
In a recent study published in the Proceedings of the National Academy of Sciences, a team of researchers led by Dartmou ...
SEP 24, 2022
Health & Medicine
The Healing Power of Nature on the Brain
SEP 24, 2022
The Healing Power of Nature on the Brain
There is a convenience that comes from living in the city, for being close to the action, but there is also a risk to th ...
Loading Comments...