Sarah Nicholas is a Ph.D. student in the Department of Soil, Water and Climate at the University of Minnesota. Her dissertation research is identifying and describing the chemistry and mineralogy of solid-phase sources of arsenic to well water in western Minnesota. Sarah expects to complete her PhD in spring of 2015 and is currently preparing a first-author paper from her dissertation research. Sarah majored in History and Geology at Macalester College and has an MS in Quaternary Studies from the University of Maine.
Sarah was part of the science party from October to December 2013 on US/RV Thompson for GEOTRACES, an NSF-nine-week trace-metal chemistry expedition from Ecuador to Tahiti. Her shipboard job was collecting and preserving deep sea particulate iron samples from the eastern Pacific Ocean using the anaerobic sample preservation techniques developed for her dissertation work in western Minnesota. Sarah hopes to continue her research on the behavior of metals and metalloids in terrestrial and marine environments and is looking for post-doc positions in this field.
During her time on the Falkor Sarah will be collecting and preserving dissolved and particulate carbon and iron from Loihi seamount. Iron is an important trace element in sea water, and a limiting factor for productivity in much of the ocean. Loihi seamount is unusual in that it discharges a lot of iron with very little sulfur. At more typical “black smoker” hydrothermal vents, most of the iron combines with sulfur to form sulfide minerals and falls to the sea floor near the vent. At Loihi, much of the iron stays dissolved or forms other types of particles that remain in the water column and are carried far from the vent. Because these iron particles oxidize very quickly, the iron samples will be filtered and preserved under inert gas to preserve their redox state at the time of collection.