Understanding the impacts of ocean acidification: A new look at key evidence from the fossil record

Ocean acidification (OA) associated with rising atmospheric CO2-levels has been identified as a major societal issue within the UN global goals 13 and 14, and Sustainable Development Goal 14.3.1: Measure and Report Ocean Acidification.

Marine calcifying organisms (those that make calcium carbonate skeletons) are particularly at risk to OA, but predicting how they will respond in the future has proved extremely challenging.

Such predictions rely on the fossil record of calcareous nannoplankton, an abundant type of marine plankton that are potentially pH sensitive and have an excellent fossil record.

Through sedimentary rock strata that record a past episode of extreme global warming, the Paleocene-Eocene Thermal Maximum (PETM; 56 million years ago), observed abundance declines of nannofossils and calcium carbonate have been interpreted as an OA-induced catastrophe.

However, in the pilot study for this project, ‘ghost’ nannofossils were discovered through the PETM, calling into question this widely accepted view.

Given that the PETM is frequently cited as a past analogue for climate change, and is repeatedly referred to in the IPCC 2022 report, it is crucial to determine whether interpretations from this event are robust.

This project will employ novel methods to uncover the true responses of calcifying organisms to the PETM, with the goal of improving predictions for climate change, and in doing so will place Swedish science at the forefront of this important societal issue.