Geomicrobiology LABORATORY @ Delaware


We study geomicrobiology--how microorganisms affect environmental chemistry and how chemistry selects for and influences the evolution of life. Our research focuses on microbe-mineral interactions in streams, soils, aquifers, caves, and deep sea hydrothermal vents. Our approach is multidisciplinary, combining geochemical field characterization and sampling, molecular biology, biochemistry, microbiology and a wide variety of microscopy and spectroscopy techniques. The core of our work involves Fe(II) oxidation and biomineralization, though we have branched out into the world of microbe-S(0) interactions.

The lab has graduate and postdoctoral research positions available. I currently advise students in Marine Biosciences, Geological Sciences, and Biological Sciences (see grad program info here: MarBio/Geo, Bio). I also welcome highly motivated undergraduate researchers from UD and other institutions. Please contact me for details!

Latest news:

also see twitter feed: @microbestalker

Fall 2018: Welcome to new PhD student Jordan Knuth!

Summer 2018: Congrats to Mike Pavia and Arkadiy Garber on successfully defending their MS theses!

Spring 2018: Clara spent much of the spring on tour as a Mineralogical Society of America Distinguished Lecturer.

Fall 2017: Welcome to new grad students Nanqing Zhou and Rebecca Vandzura, and new postdoc Jessica Keffer!

Spring 2017: Congrats to Beverly Chiu on successfully defending her MS in Geological Sciences. Her work on Chesapeake planktonic Zetaproteobacteria isolates and genomes is published here.

In between writing and defending, Beverly managed to go a cruise to East Pacific Rise, led by George Luther.

Fall 2016: Welcome to new grad students Mike Pavia (Biosci) and Arkadiy Garber (Geosci), and new undergrad Andrew Currie (Chemistry)!

Summer 2016: Sean and Clara presented our research at Goldschmidt, ISME, and the Telluride Fe biogeochemistry conferences.

Pauline and Clara went sampling in the Frasassi Caves in Italy, looking for sulfur-oxidizing Epsilonproteobacteria. Pictures coming soon....

May 2016: Clara is on sabbatical this spring at Caltech.

Four new papers recently accepted!

-Erin and Shingo’s paper on planktonic FeOB in the Chesapeake (Geobiology)

-My review on the role of microaerophilic FeOB in BIF deposition (Geobiology)

-Paper on the architecture of Fe microbial mats in Frontiers.

-Cassie’s paper on biogenic elemental S(0) formation and dissolution by Chl. tepidum.

Nov 2015: Shingo’s paper on Fe-oxidizer comparative genomics is now online at Frontiers.

Cassie, Kara, and Clara presented at GSA in Baltimore.

Oct 2015: Welcome to new postdoc Pauline Henri!

Sept 2015: Clara was promoted to Associate Professor with tenure!

August 2015: We wrapped up the summer of conferencing with a bang---Erin, Cassie, and Clara presented at the Goldschmidt Conference in Prague. Also, see our new paper on biogenic S(0) formation in Environmental Microbiology!

July 2015: Sean and Shingo presented at the Applied and Environmental Microbiology GRC. Welcome to new grad student, Beverly Chiu!

June 2015: Sean and Erin gave talks at Abscicon in Chicago.

May 2015: Clara gave a plenary talk at ASM in New Orleans.

February 2015: The group’s been busy getting the word out. We presented at the UD Microbial Systems Symposium, the Northeast Geobiology Symposium, and the UD Geological Sciences Symposium. Shingo and Erin gave talks, and the rest was posterpalooza. Next, we’ll take the show on the road: ASM in New Orleans and AbSciCon in Chicago, and Goldschmidt in Prague!

December 2014: We are armed now to be electrochemists, thanks to George Luther, who has helped equip and train our lab to do voltammetry. Here we are performing some of our first experiments.

November 2014: Welcome Kara Hoppes, a new undergrad researcher. Also, a belated welcome to Audie, the newest and smallest member of our family!

Sean’s paper was accepted at L+O (“Dynamic hydrologic and biogeochemical processes drive microbially enhanced iron and sulfur cycling within the intertidal mixing zone of a beach aquifer”). Read the paper here.

October 2014: Clara presented our research on Fe oxide sand coatings (w/ Kevin Cabaniss) and microbial Fe and S-cycling in coastal aquifers (Sean McAllister) at the ISSM conference.

August 2014: Shingo and Erin cruised the Chesapeake, looking for Fe-oxidizers in the seasonal chemocline.

May 2014: New paper with the Luther lab: Using in situ voltammetry as a tool to search for iron oxidizing bacteria: from fresh water wetlands to hydrothermal vent sites

April 2014: Welcome back Shingo Kato, as a postdoc working on Fe-oxidizer biomineralization! Welcome to Erin Field, a new postdoc working on Fe-oxidizers in groundwater-surface water transition zones!

Feb 2014: Sean McAllister gave a talk at the Ocean Sciences meeting, “Interplay between iron- and sulfur- cycling microbial communities and geochemistry along ecosystem gradients in the intertidal mixing zone of a beach aquifer.”

Jan 2014: Welcome, Cassie Marnocha, a new postdoc working on C. tepidum-elemental sulfur interactions!

Nov 2013: Two new papers!

One in ISME J, with Emily Fleming, Dave Emerson et al: Ecological succession among Fe-oxidizing bacteria. Another in IJSEM, Kato et al., reporting on a new FeOB isolate, R-1’s Japanese cousin OYT1, named Ferriphaselus amnicola, “iron bean that lives in a stream”.

Oct 2013: This month, we’re moving our Penny Hall lab next door to the Interdisciplinary Science and Engineering (ISE) Lab. We’re excited to be part of this adventure, and look forward to new collaborations. Read more about the building here.

Sept 2013: We were just awarded a new grant to work on cell-S(0) interactions involving chemolithotrophic S-oxidizers at the Frasassi Caves with Penn State collaborator Jenn Macalady! We are looking for a Ph.D. student to start this spring or summer.

July 2013: Welcome, Shane Cone, a new grad student in Geological Sciences!

Check out our new papers:

One on Fe microbial biosignatures and O2, by Sean Krepski et al. in the Geobiology Journal, including a movie of stalk formation!

And, another with our former visiting postdoc Shingo Kato in AEM, on a Japanese Fe microbial mat 16S and functional gene diversity, including a new isolate OYT1, a close cousin to our Delaware isolate R-1.

Sean McAllister presented his research on hydrothermal vent Fe-oxidizers at the Delaware Space Grant Research Symposium. He was also recognized as a DESG graduate fellow.

Clara and Sean McA. head to the Loihi Seamount to explore the ecology, biomineralogy, and functions of marine Fe-oxidizing microbes. March 15 - April 1 on the R/V Thompson. Blog and article

We were just awarded a new grant with Tom Hanson to study the interactions between a phototrophic S-oxidizer and elemental S(0). We’re looking for students and a postdoc for this project.

Shingo Kato (JCM/RIKEN) visited the lab in Jan/Feb 2013 to perform SEM and TEM of FeOB isolates OYT1 and R-1 and generally geek out on FeOB. Stay tuned for some awesome pictures.

Two new papers!

Emily Fleming et al. in FEMS Microbial Ecology, on our discovery of marine sheath-forming Zetaproteobacteria at Loihi.

Gaurav and Clara’s paper in Geobiology, on how Fe-oxidizing microbes avoid mineralization by maintaining cell surfaces at near-neutral charge.

Photo descriptions and credits:

Top left: Iron microbial formation at Tennyson Mine, WI (Tami Thomsen)

Top right: Phase contrast light micrograph of Mariprofundus ferroxydans (C. Chan)

Bottom middle: Gradient tube culture of iron-oxidizing microbes (Lisa Tossey)

Bottom right: Characteristic iridescence associated with iron oxidizers (Jill Banfield)

My mug shot (Evan Krape). Voltammetry and Chesapeake cruise (C. Chan). Group poster shots (Shingo Kato). If you use these images, please credit appropriately.



Clara Chan

Associate Professor of Geological Sciences

offices: 126 Delaware Biotechnology Institute (DBI), 470 ISE Lab

labs: 146 Delaware Biotechnology Institute, 455 ISE Lab

cschan AT