Wednesday June 24, 2026
Rutgers —
To understand how Earth’s climate is changing, we first need to understand how it has changed before. One of the best tools for doing that sits at the bottom of the ocean — tiny, fossilized shells of microscopic, single celled creatures called foraminifera. A new study published in the journal Palaeogeography, Palaeoclimatology, Palaeoecology takes a closer look at how reliably these shells can tell us about ancient ocean temperatures, specifically in the Indian Ocean.
Elisabeth Sikes, professor in the Department of Marine and Coastal Sciences and an affiliate of the Rutgers Climate and Energy Institute, is a co-author on the study alongside lead author Ryan Glaubke, a PhD student in the Department of Marine and Coastal Sciences, and colleagues from the University of Maine and Old Dominion University.
When foraminifera are alive, the ratio of magnesium to calcium in their shells changes with water temperature. After they die and sink to the seafloor, those shells preserve a record in their shell chemistry of ocean conditions was like when they were alive — like a natural thermometer frozen in time. But the tool only works well if we know exactly how to read it, and that depends on having accurate “calibration” equations — essentially, conversion charts that translate shell chemistry into temperature.