Northwestern University scientists identified ocean acidification as the cause of a major extinction event among planktic foraminifera 113 million years ago [1].
This discovery provides a critical historical precedent for how rapid changes in ocean chemistry can collapse marine ecosystems. By understanding the mechanisms that drove this ancient extinction, researchers can better predict the potential impact of modern acidification on current biodiversity.
The research focused on planktic foraminifera, which are microscopic organisms that leave behind calcium carbonate shells. These shells act as chemical archives, preserving data about the water conditions present at the time of the organism's death [1]. Scientists analyzed these chemical clues to reconstruct the environment of the Cretaceous period.
According to the findings, the acidification of the ocean triggered one of the most severe extinction events in marine history [2]. The shift in pH levels made it difficult for these organisms to maintain their shells, leading to a widespread population collapse [1].
"Using chemical clues locked inside microscopic fossils, Northwestern University scientists found evidence," the researchers said [1]. The study effectively solves what some have described as a 113-million-year-old marine murder mystery [2].
The evidence suggests that the acidification was not a gradual shift but a significant event that fundamentally altered the ocean's biological landscape [1]. By mapping the chemical signatures within the fossils, the team could pinpoint the exact timing and scale of the decline [1].
This event highlights the vulnerability of calcifying organisms to changes in carbon levels. The study underscores the fragility of the marine food web when the foundational species, such as planktic foraminifera, are compromised by chemical instability [1].
“Ocean acidification triggered one of the ocean's most severe extinctions.”
This research establishes a direct link between ocean chemistry and mass extinction in the Cretaceous period. By proving that acidification was the primary driver for the loss of planktic foraminifera, the study provides a cautionary model for contemporary climate change, where rising CO2 levels are currently increasing the acidity of the world's oceans.
