Brandy Toner

Toner Lab of Low-Temperature Geochemistry

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Iron Speciation in Deep-sea Hydrothermal Plumes The amount of iron released to the ocean by hydrothermal venting at the seafloor is approximately equal to all of the iron flushed from the continents by rivers – this is a lot of iron. With all of this iron entering the oceans, why are there large regions of the global ocean where iron availability is so low it limits life? The key to iron mobility and bioavailability is an understanding of the specific chemical form of the iron. Our recent work demonstrates that we still have a lot to learn about the suite of iron forms present in deep-sea hydrothermal plumes, as well as the trace element reactivity of iron-bearing minerals. Photo on main page (L to R): Clara Chan, Brandy Toner, Beth Orcutt, Katrina Edwards, and Emily Fleming on cruise to Loihi Seamount 2008
I am interested in understanding the biogeochemical transformations of the iron that is vented at the seafloor. I use X-rays produced at synchrotron facilities to measure the specific chemcial form of iron in hydrothermal plumes. I became involved in plume research while a postdoctoral researcher at Woods Hole Oceanographic Institution (WHOI). One of the reasons I really enjoy this research because I get to work with many talented scientists.

Sediment trap shipboard (courtsey of Chris German, copyright WHOI)	Collaborators Sirine Fakra and Matthew Marcus at the Advanced Light Source beamline 10.3.2.	Riftia patch at Tica Vent, East Pacific Rise 9 N (courtsey of Olivier Rouxel, copyright WHOI)
The measurements I make at the Advanced Light Source include: micro-probe X-ray absorption spectroscopy (XAS); micro-probe X-ray diffraction (XRD); nano-probe imaging and speciation mapping (STXM). All of these micro- and nano-meter tools are necessary to understand the chemistry of the tiny and chemically complex hydrothermal plume particles.

The seafloor near the EPR Tica Vent bsediment trap location (courtsey of Breea Govenar, copyright WHOI)	Brandy Toner at ALS BL10.3.2 (at 7 months)	Katrina Edwards, Brandy Toner, and Cara Santelli at ALS BL10.3.2.
Our first research efforts to address hydrothermal plume iron speciation were directed at samples retrieved from sediment traps moored approximately 100m from Tica Vent at East Pacific Rise - this was the RESET06 cruise. This research led to a recent publication (Toner et al. 2009 Nature Geosci.). Since the original EPR sediment trap research, I have been involved in projects with John Breier (Chip) to study plume particles from the same vent but collected from the non-buoyant plume directly using his SUPR sampler - these in situ filtered samples were analyzed fresh at ALS by me and Sirine Fakra, and the manuscript is in prep.

My first cruise - Loihi Seamount with the FeMO scientists and ROV JASON crew.	Ryan Lesniewski on R/V Thompson cruise to Loihi Seamount (Oct 2008)	On the Loihi cruise Olivier Rouxel and I collected suspended particles at different depths in the water above and around the seamount (photo: Mark Kurz)

Spectroscopists in Training: Beth! Orcutt, Sarah Bennett, and Amanda Turner at BL10.3.2 to study biogeochemical alteration of rocks in the deep sub-seafloor.	Research at the ALS: Miki Rough and Brandy Toner (UMN), Sarah Bennett, Beth! Orcutt, and Amanda Turner (USC)	Katrina Edwards "driving" at ALS in June 2009 (with Miki as navigator)
We work very hard to preserve the integrity of hydrothermal plume samples. This is essential for great science results, but is also a tough challenge because the scheduling of ship time and beamtime is incredibly difficult.

Fresh samples from Eastern Lau Spreading Center (ABE vent field) were handeled in a portable glove bag with argon at beamline 10.3.2	View of fluorescence detector in hutch at ALS BL10.3.2	Jason Sylvan (USC) and Sheri White (WHOI) collected plume particles at Eastern Lau Spreading Center (ABE vent field) with the in situ filtration device - SUPR sampler

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