Authors:

Qizhi Sun

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Sea ice is rapidly decreasing in the polar oceans, which decreases the Earth's albedo and increases solar energy absorption at the poles. This heats the ocean water and accelerates global warming. We urgently need quantitative proxies of past sea ice to provide accurate data for climate model parameterization in order to better project future sea ice changes. Our research allows us to demonstrate the viability of tetra-unsaturated alkenone biomarkers for past sea ice reconstructions and contribute to a better understanding of the complicated dynamics of polar oceans. 50 The alkenone molecules we are looking at are largely produced by group 2i haptophyte algae living on/in sea ice. This group of algae produces a characteristically high percentage of tetra-unsaturated alkenones, and because they are associated with the presence of sea ice, tetra-unsaturated alkenones are potentially great proxies for sea ice distribution. By analyzing the alkenone concentrations of polar surface sediments (sediments deposited in the last 20 or so years) and comparing them to the recent distribution of Arctic and Antarctic sea ice, we can better understand the response of these biomarker-producing algae to sea ice concentration, which enables us to more accurately forecast future change To collect our data, we extracted organic matter from ocean sediments from the Arctic and Antarctic regions and performed column chromatography to separate compounds according to different polarities. We then employed High Performance Liquid Chromatography (HPLC-MS) to analyze the concentration of alkenones in the sediments. The results give insight into the contents of organic matter in polar sediments, which leads to knowledge about environmental change and biogeochemical processes in such a rapidly changing environment. Faith Chen:

Source:

Brown / SPRINT|Undergraduate Teaching and Research Awards (UTRA)

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Qizhi Sun