Iron (Fe) is a limiting micronutrient, playing an essential role in biogeochemical cycles in the Southern Ocean. While Fe in surface seawater comes from the sources such as upwelling of Fe-rich deep waters, melting of sea ice, glacial melting and vertical mixing of sedimentary-source Fe, atmospheric deposition also delivers Fe to the Southern Ocean. However, vast regions of the Southern Ocean remain unsampled for atmospheric Fe, and the shelf region of the West Antarctic Peninsula (WAP) has never been sampled for atmospheric Fe deposition. This study provides new data into the key properties of atmospheric Fe over the Antarctic Peninsula, one of the fastest-warming regions on earth in recent decades. Project fieldwork was carried out at Palmer Station on Anvers Island off the Antarctic Peninsula (Figure 1). For the first time, an atmospheric observation platform was erected at Palmer Station on which a suite of atmospheric instruments was installed (Figure 2). New results show that Fe-containing particles in the air were dominated by coarse particles (Figure 3), suggesting significant contributions from local and regional sources. These Fe-containing particles were primarily from crustal materials. Atmospheric particles observed at Palmer Station were diverse and had different shapes, sizes, and elemental composition (Figure 4), affecting the particles? deposition rates. The average Fe solubility for total aerosol Fe was among the lowest for the global marine atmosphere, reflecting low anthropogenic impact and remoteness from continental sources. Higher quantities of Fe in the air occurred during austral summers than in winters, implying the effect of ice-free and snow-free dust sources in Antarctica on atmospheric Fe concentrations and fluxes. The atmospheric Fe deposition fluxes derived from this study suggest the importance of atmospheric contributions to the Fe in outer-shelf waters of WAP and the proximal pelagic waters of the Southern Ocean where surface water Fe concentrations are low, limiting productivity. This project has filled the critical data gap in this region and advanced our understanding of atmospheric Fe properties and deposition affecting the biogeochemical cycles of nutrients in the Antarctic coastal sea and the Southern Ocean. This project has provided excellent training and professional development opportunities to both graduate and undergraduate students who had never had such opportunities before. Students involved in this project have gained new knowledge and skills, and 70% of the participating students were minority students. This project has promoted participation of underrepresented groups in scientific research.

Last Modified: 10/30/2020
Modified by: Yuan Gao