Quantifying ocean acidification in the geologic record using the B/Ca ratio of planktic foraminifera shells

• Main Author: Haynes, Laura
• Format: Text
• Language: unknown
• Published: Montclair State University Digital Commons 2019
• Subjects: Earth Sciences; Environmental Sciences; Ocean acidification
• Online Access: https://digitalcommons.montclair.edu/sustainability-seminar/2019/fall2019/10; https://digitalcommons.montclair.edu/context/sustainability-seminar/article/1063/viewcontent/Haynes_Seminar_flier.pdf

56 million years ago, the Earth underwent a rapid climate change event called the “Paleocene Eocene Thermal Maximum” (PETM). Sedimentary records show that a massive amount of carbon was released into the atmosphere, causing ocean acidification, warming, and a widespread extinction of deep-sea organisms. Reconstructing the source and amount of carbon released during the PETM has been a major focus for paleoclimatologists as we seek to understand how the Earth system will respond to modern carbon emissions and warming. To help quantify ocean acidification at the PETM, we are using the boron content (the B/Ca ratio) of the shells of fossilized foraminifera as a proxy for past ocean pH and carbon content. I will present new calibrations for the B/Ca proxy that we have created by growing living planktic foraminifera in seawater chemistry analogous to that of the Paleogene and simulating severe ocean acidification. I will discuss the best way to apply these new calibrations from modern species to now-extinct Paleogene foraminifera and will show how our calibrations shed new light on the size and source of the PETM ocean acidification event.