News and Updates

Spring 2025:

• Congratulations to Jared for successfully defending your thesis! We're going to be sad to see you leave:(

• Congratulations to Amelia for successfully defending your thesis! You're going to do great things at your new job at American Engineering Testing in Minnesota! We'll also be sad to see you leave:(

Fall 2024:

• Congratulations to Dr. Keenan for being added to the Fulbright Specialist roster!

• Welcome to South Dakota Mines, Samantha and Claire!

Spring 2024:

• Congratulations to Dr. Keenan for receiving tenure and promotion to Associate Professor!

• Congratulations to Amelia and Jared for successfully defending their thesis proposals!

• Congratulations to Dorothy for successfully defending her MS Paleontology thesis! You will be greatly missed at SD Mines.

Summer 2023:

• New NSF Award: Drs. Keenan, Beeler, and Pagnac awarded an NSF grant (to start in January 2024) to study the paleoenvironment of western South Dakota during the Eocene-Oligocene transition by integrating sedimentology, stratigraphy, and stable isotope geochemistry. Fun science ahead for the next 3 years!

• Congratulations to Dorothy for receiving a Geological Society of America Graduate Student Research Grant to help support her work on microbial interactions with bone.  

• Congratulations to Logan for receiving a Geological Society of America Graduate Student Research Grant to help support his work on modern bone geochemistry. 

Spring 2023:

• Congratulations to Andy for receiving 2nd place in the SD Mines Student Research Symposium oral presentation (for graduate students) and to Colette for receiving 3rd place (for undergraduate students)! And Will did a great job too!

• Congratulations to Andy and Will on their successful thesis defenses! You will be missed after you graduate! Colette will be missed too!

• **Upcoming conference October 2023, Banff, Canada**: the International Society for Environmental Biogeochemistry (ISEB) and the International Society for Subsurface Microbiology (ISSM) are co-hosting a conference in the lovely city of Banff in October. For more details, info on registration, and invited speakers, check out our website: https://iseb-issm2023.org/

• New publication: Dr. Keenan published a paper in Applied Geochemistry modeling the thermodynamics of bone and apatite mineral stability in a wetland system.

• Congratulations to Jessica on her defense and graduation (December)

Fall 2022:

• New publication: Congratulations to Colleen on her publication in PLOS ONE evaluating fossil dissolution rates!

  • Check out the press release as well--South Dakota Mines Study Shows Fossil Dissolution Rates 

• GSA Presentations featuring current and former members of the lab

(1)   Beeler, S.R.* and Keenan, S.W. Assessing changes in lipid biomarkers in soils associated with animal decomposition over decadal time scales. Poster on Oct. 10th at 2 pm; 125-8 (booth 18).

(2)   Keenan, S.W.*, Beeler, S.R., DeBruyn, J.M., and Mason, A.R. Beaver decomposition leaves long-lasting biogeochemical impacts on surface and subsurface soils. Invited talk on Oct. 12th at 9:05 am; 229-5.

(3)   Rich, A.* and Keenan, S.W. Lithological influences on mosasaur fossil taphonomy within the Pierre Shale Formation of South Dakota. Poster on Oct. 9th at 2 pm; 63-26 (booth 109).

(4)   Sullivan, C.* and Keenan, S.W. Quantitative assessment of fossil bone dissolution under acidic conditions—implications for guiding field collection efforts. Talk on Oct. 10th at 9:50 am; 90-7.

(5)   Whittenberg, W.* and Keenan, S.W. The use of medical CT scanning to analyze ammonoid shell wall thickness as a response to predation. Poster on Oct. 9th at 2 pm; 63-9 (booth 92).

*Presenting Authors

• Welcome to the three new graduate students joining the Geobiology Lab!

  • Kayla Esses

  • Logan McCutcheon

  • Dorothy Rodarte

Summer 2022:

• Dr. Keenan participated in an NSF-funded workshop on improving graduate student preparedness for the future workforce in Washington, D.C.

• Drs. Keenan, Beeler, and Pagnac have been busy visiting White River Group deposits to find the perfect rocks for future research. We've also been using the handheld XRF instrument to collect preliminary data.

• Congratulations to Colleen and Michael on their graduation from South Dakota Mines! The lab will not be the same without you two! Best of luck and visit often!

Spring 2022:

• Congratulations to Andy and Will on successfully defending their proposals!

• Congratulations to Michael on successfully defending his MS Paleontology thesis titled, "The impact of carbon availability and geochemical variation on habitability of epigenic cave systems"

• Dr. Keenan presented new and exciting research at the joint Rocky Mountain/Cordilleran Section meeting of GSA in Las Vegas, NV over spring break. As past chair of the Rocky Mountain Section, she also participated in our *first* in-person section meetings since 2019!

• New publication: Congratulations to Alex for leading another incredibly and collaborative project!

  • Emmons, A.L., Mundorff, AZ., Hoeland, K.M., Davoren, J., Keenan, S.W., Carter, D.O., Campagna, S.R., and DeBruyn, J.M. (2022). Postmortem skeletal microbial community composition and function in buried human remains. mSystems (in press). 

• Congratulations to Colleen on successfully defending her MS Paleontology thesis titled, "Fossil dissolution rates at varying pH: a pilot study." 

• Drs. Keenan and Beeler awarded an NSF grant! This grant will allow us to purchase and provide training on a brand new ion chromatography instrument (Dionex ICS-6000) to be used in research and teaching. 

• Congratulations to Will for receiving the 2022 René M. Vandervelde Research Grant through the Association of Applied Paleontological Sciences to help support his MS research!

• Congratulations to Andy for publishing his *first* peer-reviewed paper based on his Undergraduate Research at Beloit College! Check it out here: Rich and Zambito (2022)

Fall 2021:

• The Geobiology Lab had a great showing at GSA in Portland! Collectively, we had 3 presentations on topics ranging from caves to fossil bone dissolution. Great work everyone!

• Congratulations to Jessica on successfully defending her MS thesis proposal.

• Welcome to the 4 new MS Paleontology Students in the Geobiology Lab!

  • Michael Nieland (B.S. Geology from SD Mines)

  • Rhys Watson (B.S. Geology from the University of Wyoming)

  • Andy Rich (B.S. Geology from Beloit College)

  • Will Wittenberg (B.S. Earth Sciences from the University of Memphis)

Summer 2021:

• Michael was featured in an SD Mines press release about his successful NASA research stipend: Mines-Students-Win-NASA-Funding

• Field work has started with Michael Cyrier (SD Mines) and Jordon Cano (OLC), with help from Jason Tinant (OLC) and Al (OST)! We're busy in the field twice a week collecting surface water samples as part of the PEEC grant. 

  • We're planning to sample from June through September at 5 sites.

Spring 2021:

• Michael and Colleen both successfully defended their MS thesis proposals and will spend the summer collecting samples and conducting experiments! Congrats!

• Congratulations to Colleen for receiving a research grant from the Paleontological Society to help support her MS research on fossil bone dissolution rates!

• Congratulations to Grace on successfully defending her MS Paleo thesis titled: Using fossil bone geochemistry and age reports to reconstruct diagenesis at the Pig Dig Site, Badlands National Park, SD! Grace will start a Scientists in the Park position at Badlands this May after graduation.

• Congratulations to Michael on being awarded a SD Space Grant Consortium Graduate Student Research Stipend, funded by NASA, to support your MS research on cave geomicrobiology in the Black Hills! 

Fall 2020:

• Welcome to Michael, Jessica, and Colleen, new MS Paleontology graduate students! 

• New publication: Congratulations to Alex for leading this awesome study published in PLoS One and available to read for free online! 

  • Emmons, A.L., Mundroff, A.Z., Keenan, S.W., Davoren, J., Andronowski, J., Carter, D. O., and DeBruyn, J.M. (2020). Characterizing the postmortem human bone microbiome from surface decomposed remains. PLoS One, 15:e0218636, DOI:10.1371/journal.pone.0218636.

Spring 2020:

• Despite the abrupt end to the semester, Michael and Zakary completed their projects, Grace successfully defended her proposal (congrats!), and we're slowly returning to a new normal and preparing for Fall.

• Congratulations to Grace for receiving the AAPS Charles Sternberg Scholarship AND the Richard Osgood Award through the Paleontological Society to support her research on the Pig Dig Site at Badlands National Park! This funding will help to support lab-based analyses of the fossils, travel to visit the Pig Dig Site, computational support, and supplies for the curation of fossils in SDSMT collections.

• Congratulations to Michael as well for receiving funding through the Geological Society of America, Rocky Mountain Section to support his undergraduate research! He will use the funding to purchase safety equipment to allow for continued (and expanded!) sampling this summer at Rushmore Cave. Thank you to all the funders for supporting student research at Mines!

• February:

  • Busy month in the lab! Michael and I have been collecting samples every other week, and Michael is busy analyzing the data from sampling efforts in Rushmore Cave. Zakary is also busy collecting weekly data from his mesocosm experiments in the lab.

  • New publication: Congratulations to Nell for leading this transformative study! 

    • Fanter, C.E., Lin, Z., Keenan, S.W., Janzen, F.J., Mitchell, T.S., and Warren, D.E. (2020). Development-specific transcriptomic profiling suggests new mechanisms for anoxic survival in the ventricle of overwintering turtles. Journal of Experimental Biology, 223, DOI: 10.1242/jeb.213918.

Fall 2019:

• November:

  • Field work with Michael continues! We are busy collecting samples and analyzing data from our bi-monthly visits to Rushmore Cave. Zakary also collected soils and some preliminary data from his senior research project focused on carbon cycling in soils at Kenny Brown's ranch in Hermosa. Poster presentations will be Dec. 6th in PRL! 

• October:

  • Field work with Michael begins! We spent a lovely Saturday collecting data (temperature, carbon dioxide, relative humidity) in Rushmore Cave with the assistance of Kevin Chase for Michael's senior research project.

  • New publication: How do soils respond to a pulsed input of nutrients? How far below and adjacent to a carcass is isotopic enrichment? Read for free online to find out!

    • Keenan, S.W., Schaeffer, S.M, and DeBruyn, J. M. (2019). Spatial changes in soil stable isotopic composition in response to carrion decomposition. Biogeosciences, 16:3929-3939, DOI: 10.5194/bg-16-3929-2019.

Summer 2019:

• July:

  • Workshop Participation: Dr. Keenan participated in the Early Career Geoscience Faculty Workshop in College Park, MD. In addition to learning invaluable teaching and research skills, this was also a great networking opportunity! #EarlyCareer2019

  • New publication: What happens to vertebrate tissue stable isotopic composition as tissues decompose?

    • Keenan, S.W. and DeBruyn, J. M. (2019). Changes to vertebrate tissue stable isotope (δ15N) composition during decomposition. Scientific Reports, 9:9929, DOI: 10.1038/s41598-019-46368-5.

Spring 2019:

• April:

  • Congratulations to Seth for winning 2nd place in the SDSMT Student Research Symposium for his poster titled: Taphonomic survey of vertebrate fossils from the Pierre Shale near Hermosa, SD. Great job Seth!

  • New publication: This is part of a special issue on Acid-Base physiology!

    • Keenan, S.W., Pasteris, J.D., Wang, A., and Warren, D.E. (2019). Heterogeneous bioapatite carbonation in western painted turtles is unchanged after anoxia. Comparative Biochemistry and Physiology, Part A.

• January:

  •  Lab setup continues, and the Licor-830 CO2 analyzer (dubbed Yoda) is up and running! This will allow us to measure how soil microorganisms respond to changes in nutrients in the lab and in the field.

  • Seth is continuing his undergraduate research (GEOL 465) and is busy in collections examining fossil bones from the Pierre Shale. Once the snow melts, we will be out in the field to assess fossil weathering in-situ.

Fall 2018:

• December:

  • Lab setup is moving forward, and we should have a Licor-830 CO2 analyzer up and running shortly! 

  • New publication: Congratulations to everyone for making this research possible and for getting this publication out. This was by far the most collaborative work I've done to date!

    • Keenan, S.W. Emmons, A.L., Taylor, L.S., Phillips, G., Mason, A.R., Mundorff, A., Bernard, E.C., Davoren, J., and DeBruyn, J.M. (2018). Spatial impacts of a multi-individual grave on microbial and microfaunal communities and soil biogeochemistry. PLoS One.

• October:

  • Field work with Seth! We spent a lovely October day with Kenny Brown prospecting for Late Cretaceous marine fossils in the Pierre Shale. Thanks to GPS, we can check back on our taphonomy sites in the spring!

  • Calen and Seth are working on their undergraduate senior research projects and making plans for data collection and analysis this semester and next. Exciting taphonomy research ahead! 

• August:

  • Dr. Keenan arrived at SDSM&T! Lab set-up is currently underway, and two undergraduate students should begin their senior research projects within the next few months! 

  • New publication: Congrats to Dean for completing his MS thesis and getting this great publication out!

    • Odegard, D.T., Sonnenfelt, M.A., Bledsoe, J.G., Keenan, S.W., Hill, C.A, and Warren, D.E. (2018). Changes in the material properties of the shell during simulated aquatic hibernation in the anoxia-tolerant painted turtle. Journal of Experimental Biology.