PALEOCLIMATE RECONSTRUCTION AND COMPARISON TO MODERN CLIMATES IN CAPE ESPENBERG ALASKA

The Arctic is experiencing rapid warming and ecological shifts due to climate change and the compounded effects of polar amplification. There is a paucity of information surrounding the carbon cycling response of Arctic coastal marsh environments to these forces. The Cape Espenberg barrier beach system has been prograding for at least 4000 years, preserving a record of environmental change. This study aims to determine the Arctic carbon and mineral accumulation trends in marsh environments at Cape Espenberg for both paleo (~2500 yrs) and modern timeframes. Analytical analysis through radioisotope (¹³⁷Cs, ²¹⁰Pb, and ¹⁴C), stable isotope spectrometry (ẟ¹³C, %C, ẟ¹⁵N, %N, and C:N), and dry bulk density (DBD) measurements yield a comprehensive physical and chemical dataset. Preliminary results of DBD, %C, and ẟ¹³C, agree well with the stratigraphic sequence of the sediment cores. Denser marine sands have isotopically heavier ẟ¹³C isotopes (-11‰ to -16‰), higher DBD (≥0.5 g/cm³), and lower %C values. Lighter peat materials have isotopically lighter ẟ¹³C isotopes (-26‰ to -31‰), lower DBD (≤0.5 g/cm3), and higher %C values. The results of this study will contribute towards understanding the dynamism of Arctic coastline mineral and carbon cycling, and can be used to better predict future ecological responses to a warming climate.