TRACKING GLACIAL-INTERGLACIAL CYCLES USING DIATOM MORPHOMETRICS IN THE AMUNDSEN SEA, ANTARCTICA(IODP LEG 379)

As global climate continues to rapidly change over the coming decades, West Antarctica is a significant point of interest due to its past vulnerability to ice sheet collapse. Sediment samples collected from the Amundsen Sea on IODP expedition 379 allowed for our analysis of a more continuous record of Pleistocene glacial-interglacial cycles.

Following methods from Kloster et al. 2018, morphometric changes of the open marine diatom Fragilariopsis kerguelensis can be tracked as a proxy for summer sea surface temperature (SSST). Through direct analysis of high magnification microscope scans, two distinct morphotypes became clear throughout our samples. The samples were then analyzed with imaging software SHERPA to better constrain change in total valve area.

Although results are preliminary, they show a distinct change in the morphologies of F kerguelensis which will be further investigated into correlations for SSST changes. Morphotype 1 can be seen consistently throughout all diatom bearing samples, whereas morphotype 2 appears in the glacial periods of the diatom bearing samples.

While interpreting morphotype variability for environmental changes is still in its earliest stages, the findings show strong correlations to summer sea surface temperature changes. Tracking these changes throughout glacial to interglacial transitions can help with modeling efforts to infer sea level rise as a result of Antarctic ice sheet loss. These changes can help further constrain interpretations of Past Antarctic Ice Sheet changes, while helping better understand future models for sea level rise as the planet continues to warm.

The impact that global warming will have on humans gives great meaning to this research as we advance our understanding of the dynamics that occur throughout Antarctica and the balance of ice sheet loss and sea level rise.