Two studies have shed light on planetary events 100 million years ago by looking at the fossilized remains of deformed seashells.
The work shed particular light on the Ocean Anoxic Event 2 (OAE2), which occurred about 100 million years ago and cut off the oxygen supply to the oceans, resulting in mass marine extinction.
The team looked at the fossils to understand what happens when massive amounts of CO2 is released into our oceans. At the time, the huge underwater volcanic eruptions released enormous amounts of gas into the ocean, causing the event.
Scientists conducted two complementary studies, one published in the journal Nature Geoscience and the other published in the journal Communications Earth & Environment.
According to Brad Sageman, a senior author of both studies from Northwestern University:
“Ocean acidification and anoxia resulted from massive CO2 release from volcanoes. These major CO2 emission events in Earth’s history provide the best examples we have of how the Earth system responds to very large inputs of CO2. This work has fundamental applicability to our understanding of the climate system, and our ability to predict what will happen in the future.”
While another senior co-author, Andrew Jacobson from Northwestern, also stated:
“Based on isotopic analyses of the element calcium, we propose a possible explanation for the Plenus Cold Event, which is that a slowdown in biocalcification rates due to ocean acidification allowed alkalinity to accumulate in seawater. Increased alkalinity led to a drawdown of CO2 from the atmosphere. It could very well be the case that such cooling is a predictable — but transitory — consequence of warming. Our results for OAE2 provide a geological analog for ocean alkalinity enhancement, which is a leading strategy for mitigating the anthropogenic climate crisis.”
You can find the original research here.