Grace Kortum, ’21, Geosciences

Grace Kortum ’21

Major

Geosciences

Project Title

Impacts of Slow Growth Rates on Coral Geochemical Climate Proxies

Certificate(s): Statistics and Machine Learning

I worked to improve our understanding of trends in sea-surface temperature and rainfall over the past several centuries, which is essential for projecting the effects of anthropogenic climate change. Corals serve as ideal records for studying long-term climate variability in the ocean because they preserve climate information in their skeletons as they grow. I collected powder samples from a coral-skeleton core from Cuba that contained over 200 years of information. My mentor and I used a spectrometer to measure the samples’ strontium and barium content. High strontium levels indicate low sea-surface temperatures, while high barium levels suggest high rainfall. With these data, we can observe the yearly cycle of summer heat and spring rainfall, along with longer term changes in climate. I also investigated how the unusually slow growth rate of some corals potentially affects their ability to serve as climate records. I learned new laboratory techniques and developed my skills in Excel, MATLAB, and statistics as I analyzed our data in the context of existing global climate datasets. This was a great opportunity to learn about paleoclimate research, as well as contribute to our understanding of past climate.