Open Access Thesis
Date of Award
Mark M. Baskaran
Understanding the biogeochemical cycles of the Arctic Ocean is highly significant due to its many unique characteristics which impact the cycling of important trace elements, isotopes, and nutrients. Furthermore, with its seasonally-changing sea ice extent and substantial role in the global radiation balance, the Arctic is considered a sensitive indicator of global change. The study of 210Po and 210Pb disequilibria is used to determine 1) the residence time of ice-rafted sediments in sea ice, 2) ice floe dynamics such as ice accumulation rates, and 3) biogeochemical characterization of the Arctic due to the natural occurrence and particle reactivity of 210Po and 210Pb. The “age” of ice-rafted sediments ranged from 56-136 days, and transport rates of 0.08 to 0.17 m/s were observed, consistent with previous reports, with the higher rates potentially influenced by non-conservative behavior of radionuclides during melt season. The mechanisms of isotopic disequilibria with depth in ice cores is not yet clearly understood, but model-based estimates of ice accumulation range from 0.08 – 7 cm/d (mean = 1.4 cm/d). Wide-scale 210Po deficiency in water columns of the central and western Arctic (integrated AR’s = 0.51± 0.07 and 0.56 ± 0.07 for ST-30 and ST-43, respectively) indicate early summer export of 210Po with biogenic particles.
Krupp, Katherine Denise, "Using 210po/210pb Disequilibria To Characterize The Biogeochemistry And Quantify The Dynamics Of Sea Ice In The Arctic" (2017). Wayne State University Theses. 573.