Fe variation characteristics and sources in snow samples along a traverse from Zhongshan Station to Dome A, East Antarctica

摘要

Iron concentrations in the Southern Ocean are thought to act as a driver of the regular glacial-interglacial cycles in atmospheric carbon dioxide (CO2). This study presents the concentrations of bioavailable Fe (dissolved Fe (DFe) and total dissolved Fe (TDFe)), major ions (Na+, K+, Mg2+, Ca2+, Cl-, NO3-, SO42- and methanesulfonic acid (MSA)), heavy metal elements (Sr, Pb, V, Ti and Cd), and rare earth elements (REEs; specifically, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu) and the oxygen and hydrogen isotopic compositions (delta O-18 and delta D) from a series of surface snow samples collected during from January 22 to February 5, 2017 along a traverse from Zhongshan Station to Dome A in East Antarctica. The results reflect the Antarctic surface snow Fe and the other trace element concentrations on the East Antarctica ice sheet. In particular, the DFe and TDFe concentrations were measured using inductively coupled plasma sector fieldmass spectrometry (SF-ICP-MS). The concentration patterns of DFe and TDFe show three different stages along this transect. First, there is an abrupt decrease with distance inland from the coast and then a slight decreasing trend with increasing elevation. The maximum concentrations were observed at distances of 450-600 km from the coast, indicating that there are different potential sources and/or transporting air masses. The variations show that the sources and processes that deliver bioavailable Fe differ along this transect. These data are useful for assessing bioavailable Fe release from the Antarctic ice sheet. (C) 2019 Elsevier B.V. All rights reserved.