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| A drone photo of the JOIDES Resolution in the Mentelle Basin, where Northwestern scientists drilled for ancient sediment. Photo Credit: Gabriele Tagliaro, University Sao Paulo |
Scientific Frontline: Extended "At a Glance" Summary: Ocean Anoxic Event 2 and Ocean Acidification
The Core Concept: Ocean Anoxic Event 2 (OAE2) was a major global environmental crisis approximately 100 million years ago marked by severe ocean deoxygenation and widespread acidification driven by massive volcanic carbon dioxide emissions.
Key Distinction/Mechanism: Unlike typical modern warming trends, OAE2 featured a unique feedback loop where extreme ocean acidification temporarily suppressed calcification rates, allowing seawater alkalinity to accumulate and ultimately triggering a transient cooling period known as the Plenus Cold Event.
Major Frameworks/Components:
- Calcium isotope ratio analysis of fossilized planktonic foraminifera to evaluate physiological stress caused by ocean acidification.
- Deep-sea sedimentary core analysis identifying abrupt depletions in calcium carbonate minerals.
- Integration of geological outcrop data from Gubbio, Italy, and the Western Interior Seaway.
- Geochemical modeling linking ocean alkalinity accumulation to carbon dioxide drawdown during the Plenus Cold Event.
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