Research

Iron Speciation in Deep-sea Hydrothermal Plumes - I am involved in research at the East Pacific Rise 9N, Mid-Atlantic Ridge Rainbow Vent Field, Loihi Seamount, and the Eastern Lau Spreading Center. These projects are focused on building a detailed understanding of iron biogeochemistry, from the moment iron-laden hydrothermal fluids hit cold seawater, in the plume as it rises to neutral buoyancy, and in the water column as the plume disperses.

Breier, J.A., Rauch, C.G., McCartney, K., Toner, B.M., Fakra, S.C., White, S.N., and German, C.R. (2009).  Deep Sea Research Part I. 56:1579-1589  A suspended particle rosette multi-sampler for discrete, biogeochemical sampling in low particle density waters. 

Toner, B. M., Fakra, S. C., Manganini, S. J., Santelli, C. M., Marcus, M. A., Moffett, J. W., Rouxel, O., German, C. R., and Edwards, K. J., 2009. Preservation of iron(II) by carbon-rich matrices in a hydrothermal plume. Nature Geosci, doi:10.1038/ngeo433.

New collaborator: Greg Dick (University of Michigan)

Photo (L to R): Clara Chan, Brandy Toner, Beth Orcutt, Katrina Edwards, and Emily Fleming on cruise to Loihi Seamount 2008

Iron Speciation in the Deep Terrestrial Biosphere - I am involved in a new project at the Soudan Underground Mine State Park, MN. The focus of the project is on rock-water interactions at 0.5 miles depth, and the biogeochemical transformations of iron and carbon as anoxic groundwater bubbles into tunnels with ambient atmosphere.

Collaborators: Jeffrey Gralnick, Calvin Alexander, Scott Alexander, Ryan Lesniewski (University of Minnesota - Twin Cities), Jim Essig (DNR)

Chemical and Microbial Rock Weathering at the Seafloor - I am involved in research at the East Pacific Rise 9N and Juan de Fuca Ridge that addresses sulfide mineral weathering and the microbial ecology of the bacteria inhabiting these deposits. Watch for a new paper from Ryan Lesniewski on the microbial ecology of extinct chimney in the coming months!

Toner, B. M., Santelli, C. M., Marcus, M. A., Wirth, R., Chan, C. S., McCollom, T., Bach, W., and Edwards, K. J., 2009. Biogenic iron oxyhydroxide formation at mid-ocean ridge hydrothermal vents: Juan de Fuca Ridge.GCA 73, 388-403.

Toner, B. M., Rouxel, O., Santelli, C. M., and Edwards, K. J., 2008. Sea-floor weathering of hydrothermal chimney sulfides at the EPR 9 N: Chemical speciation and isotopic signature of Iron using X-ray absorption spectroscopy and laser-ablation MC-ICP-MS. GCA 72, A951-A951.

Geochemistry of Arsenic in Groundwater - I am involved in research in the Traverse-Grant area of west-central MN. The goal of the research is to understand the processes driving arsenic contamination of domestic well water.

The project integrates a diversity of perspectives and tools: geographic information systems (GIS), laboratory-based geochemistry, and synchrotron-radiation X-ray absorption spectroscopy (XAS). We have external partners at a number of MN state agencies. In our lab, Ph.D. student Sarah Nicholas will start this summer, and Lindsey Brisoce is leading the charge on the GIS, with expert help from Joel Nelson. We have a UROP, Sara Baldvin, joining the group to do sequential extractions of arsenic from archived cores this summer.

Collaborators/Partners: Melinda Erickson (USGS), Alan Knaeble and Carrie Jennings (MN Geological Survey), Richard Soule and James Lundy (MN Department of Public Health)

Speciation of Catalyst-Elements in Aerosols - This research examines platinum (Pt) and vanadium (V) speciation in aerosols emitted by vehicles. These elements are introduced to vehicles as fuel additives (Pt) or as solid catalysts (Pt, V) to improve combustion and reduce air pollution. The exact chemical form of Pt or V in particles emitted by vehicles determines the toxicity of the particles.

Collaborators: Martin Shafer and James Schauer (University of Wisconsin - Madison).

Phosphorus Speciation in Agricultural Soils - We are examining the form of phosphorus (P) in agricultural soils having a long history of organic-P (biosolids) or inorganic-P additions. This work is part of an international collaboratory program, BARD - Binational Agricultural Research and Development Fund.

Collaborators: Paul Bloom and Shahida Quazi (University of Minnesota - Twin Cities)

Photo: Paul Bloom at the Advanced Photon Source.