The Cooperative Institute for Climate, Ocean, and Ecosystem Studies

Hi, my name is Rachel Mutti and I am a Marine Biology and Ecology major at the University of Miami. This summer, I had the opportunity to work with Drs. Sophie Nuber and Mo Walczak on a project that reconstructed past ocean climate conditions using foraminiferal assemblages from sediment cores collected in the Santa Barbara Basin.

Foraminifera are tiny marine protists that build calcium carbonate shells and are highly sensitive to environmental conditions such as temperature, salinity, and nutrient availability. Because different species thrive in different oceanic conditions, their relative abundance in sediment layers can serve as a natural archive of climate variability. My project focused on comparing two distinct time periods: the Younger Dryas, a cold climate reversal event that occurred about 12,900–11,600 years ago, and the early Holocene, which marked the onset of the relatively warm and stable climate we live in today. I spent much of my summer identifying and counting planktonic foraminifera species under the microscope—work that was both meticulous and rewarding. From these assemblages, I was able to detect statistically significant ecological shifts: smaller, cooler-water species dominated during the Younger Dryas, while larger, warmer-water indicators increased during the Holocene. These results demonstrate how climate transitions are reflected in even the smallest components of marine ecosystems, displaying the sensitivity of ocean systems to environmental change.

Beyond the scientific findings, this internship was an invaluable experience in research and professional development. I gained hands-on skills in paleoceanography and quantitative data analysis, while also learning how to frame my results within larger questions about global climate systems. Just as importantly, I practiced patience, attention to detail, and persistence—essential qualities for both lab work and scientific inquiry. The CICOES REU helped me build technical skills and also gave me the confidence and clarity to pursue a career in marine science communication. I am beyond grateful to my mentors and peers for their support, guidance, and community throughout this unforgettable summer.

Project Introduction

Research Poster