photo by Felix Kunze

Students and Collaborators










Current Collaborators

My two most active projects are listed below:

Mass extinctions in the Late Devonian (aka the DAGGER project) - see https://devonian.appstate.edu

Manganese geomicrobiology - see https://geomicrobiology.appstate.edu 

Science Communication:

I also have a science communication collaboration with photographer Felix Kunze and videographer Magnus Karlson. A picture is worth a thousand words, and Felix and Magnus help our team tell the public about our science. 

Current Students

Anna-Maria Riley (MS Biology)

Anna-Maria is studying the impact of human traffic and artificial lighting on microbial communities in show caves in the southern Appalachians. Co-advising with Dr. Suzanna Bräuer.

Bo Strickland '25 - Independent Study (Geology)

Bo is characterizing manganese oxide deposits from Calvert Cliffs, MD using a variety of analytical techniques.

Lucca Scoggins '23 - Independent Study (Environmental Science)

Lucca is characterizing nanoparticles and minerals in sediments in Appalachian cave systems using transmission electron microscopy, to see which types of particles can be used as a tracer of human impact in cave environments. 

Ricky Carland '24 - Senior Thesis (Geology)

Ricky is looking for mineralogical clues about the Late Devonian mass extinctions at the Frasnian-Famennian and Devonian-Carboniferous boundaries in sediments from the Great Basin of Utah.

Vanya Dill '26 - Independent Study (Geology)

Vanya is looking at the evolution of magma chemistries across the Late Devonian island arc systems of the Central Asian Orogenic Belt

Ben Goodridge '25 - Independent Study (Environmental Science)

Ben is modeling different groundwater flow regimes to identify mixing zones of submarine groundwater discharge in shallow marine settings that could influence/alter the paleotemperature calculations that rely on oxygen isotopes.

Gabriel Wheaton '25 - Independent Study (Geology)

Gabriel is looking at the alteration mineralogy of Devonian shallow-water sediments in volcanic island arc environments in China and Mongolia to track how alteration mineralogy can provide clues to unusual isotope signatures.

Miguel Moreno '27 - Independent Study (Geology)

Miguel is working on the economic geology potential of black shales from the Appalachian Basin that cross the Frasnian-Famennian boundary, particular in regards to metals. He is comparing the metals content from the more restricted northern end of the Appalachian Basin to areas in the southern end of the basin that were closer to the open ocean during the Devonian. 

Past Students

Jacquelin Foronda '23 - Independent Study and Senior Thesis (Environmental Science)

Mapping destruction and rebound on an active margin of the Middle to Late Devonian in Shine Jinst, Mongolia (second reader and co-advisor: Dr. Johnny Waters)

Cara Cywinski '23 - Independent Study and Senior Thesis (Environmental Science)

Redefining the Late Devonian Kellwasser Event: New Data from the Xom Nha Formation, Central Vietnam (second reader and co-advisor: Dr. Johnny Waters)

Bryce Norvell '23 - Masters Thesis (Biology)

The effects of substrate geochemistry on the distribution of manganese oxidizing bacteria in caves of the Upper Tennessee River Basin (co-advised with Dr. Suzanna Bräuer)

Carter Smith '23 - Senior Thesis (Environmental Science) - second reader

Constraining the timing of the Late Devonian (Frasnian-Famennian) Mass Extinction in the Great Basin region, western USA: evidence using carbon and sulfur stable isotopes (primary advisor: Dr. Cole Edwards)

Yasmine Ketchie '24 - Independent Study (Environmental Science and Biology)

Method development for characterizing and quantifying microplastic pollution in cave environments in the southern Appalachians.

Lilith Hazzard '22 - Senior Research (Geology)

Titanium mobility in shallow marine sediments in the Devonian of western Mongolia.

Grant Fox '24 - Independent Study (Environmental Science)

Analysis of manganese oxidizing microbes from show caves using transmission electron microscopy.

Alex Zacher '21 - Independent Study (Geology)

Framboidal pyrite distributions and calculating the degree of anoxia in sediments from Belgium.

Logan Little '21 - Senior Thesis (Geology) - second reader

Principal component analysis of trace elements preserved in marine sediments across the Devonian-Carboniferous boundary  (primary advisor: Dr. Steve Hageman)

Kathleen (Katie) Duckett '21 - Independent Study and Senior Thesis (Geology)

Late Devonian rocks from a new site: the Bayankhoshuu Ruins of Southwestern Mongolia (second reader and co-advisor: Dr. Johnny Waters)

Katrina Godsey - Independent Study (Biology)

Manganese oxidizing fungi and bacteria from acid mine drainage sites in the southern Appalachians (co-advised with Dr. Suzanna Bräuer)

Morgan Smith '20 - Masters Thesis (Biology)

The comparison of manganese(II) oxidizing microbes in two cave systems (co-advised with Dr. Suzanna Bräuer)

Ginny Brown '20 - Senior Thesis (Geology)

EBSD and Trace Element Analysis of Replacement Dolomite in the Latemar Platform in Italy (second reader: Dr. Jamie S. Levine)

Allison Dombrowski '20 - Independent Study and Senior Thesis (Geology)

Expressions of Late Devonian Bioevents in the CAOB- New Data from the Samnuuruul Formation, Southwestern Mongolia (second reader and co-advisor: Dr. Johnny Waters)


Papers resulting from Allison's Research: *Paschall, Olivia C., Carmichael, Sarah K., Waters, Johnny A., Koenigshof, Peter, Ta, Phuong H. Komatsu, Toshifumi, and *Dombrowski, Allison D., 2019, The Hangenberg Event in Vietnam: sustained ocean anoxia with a volcanic trigger?, Global and Planetary Change (Special issue on Devonian global changes - recent advances and challenges in different domains, eds. G. Racki and P. Wignall), v. 175, p. 64-81 (DOI: 10.1016/j.gloplacha.2019.01.021) - click here for institutional repository copy with supplemental data Ariuntogos, M., Königshof, P., Hartenfels, S., Jansen, U., Nazik, A., Carmichael, S. K., Waters, J. A., Sersmaa, G., Crônier, C., Ariunchimeg, Y., *Paschall, O. C., and *Dombrowski, A., 2020, The Hushoot Shiveetiin gol section (Baruunhuurai Terrane): Sedimentology and facies from a Late Devonian island arc setting: Palaeobiodiversity and Palaeoenvironments (special issue: The Central Asian Orogenic Belt (CAOB) during Late Devonian: new insights from southern Mongolia) (DOI: 10.1007/s12549-020-00445-0)

Ben Neunsinger '19 - Independent Study (Geology)

Pilot Project: Role of crystallographic orientation on microbial colonization of mineral surfaces.

Kaitlyn Anthony '24 - Smoky Mountain STEM Summer Research Experience (Geology)

Framboidal pyrite distributions and calculating the degree of anoxia in sediments from China.

Olivia Paschall '18 - Independent Study and Senior Honors Thesis (Geology)

Exploring Late Devonian mass extinctions and ocean anoxia events in understudied paleoenvironments of Asia (co-advised with Dr. Johnny Waters, second reader Dr. Bob Swarthout)


Papers resulting from Olivia's Research: *Paschall, Olivia C., Carmichael, Sarah K., Waters, Johnny A., Koenigshof, Peter, Ta, Phuong H. Komatsu, Toshifumi, and *Dombrowski, Allison D., 2019, The Hangenberg Event in Vietnam: sustained ocean anoxia with a volcanic trigger?, Global and Planetary Change (Special issue on Devonian global changes - recent advances and challenges in different domains, eds. G. Racki and P. Wignall), v. 175, p. 64-81 (DOI: 10.1016/j.gloplacha.2019.01.021) - click here for institutional repository copy with supplemental data Ariuntogos, M., Königshof, P., Hartenfels, S., Jansen, U., Nazik, A., Carmichael, S. K., Waters, J. A., Sersmaa, G., Crônier, C., Ariunchimeg, Y., *Paschall, O. C., and *Dombrowski, A., 2020, The Hushoot Shiveetiin gol section (Baruunhuurai Terrane): Sedimentology and facies from a Late Devonian island arc setting: Palaeobiodiversity and Palaeoenvironments (special issue: The Central Asian Orogenic Belt (CAOB) during Late Devonian: new insights from southern Mongolia) (DOI: 10.1007/s12549-020-00445-0)

Moriah Van Voorhis '19 - Independent Study (Biology)

Electron microscopy of manganese oxidizing microbes from acid mine drainage sites.

Robert Thomas '17 - Independent Study and Senior Thesis (Geology)

Peeking out of the basins: looking for the late Devonian Kellwasser event in the open ocean in the Central Asian Orogenic Belt, southwestern Mongolia (second reader and co-advisor: Dr. Johnny Waters)

John Granholm '17 - Independent Study (Geology)

Sedimentation and anoxia across the Devonian-Carboniferous boundary in Namur-Dinant syncline, Belgium (co-advised with Dr. Johnny Waters)

Kieran Krommes '18 - Independent Study (Geology)

Sedimentology of D-C boundary mudstones in the Appalachian Basin in Virginia (co-advised with Dr. Johnny Waters)

Travis Hartney '16 - Independent Study and Senior Thesis (Geology)

Petrographic and mineralogical analysis of volcanic clasts: Oldoinyo Lengai, Tanzania (second reader and co-advisor: Dr. Cynthia Liutkus-Pierce)


Papers resulting from Travis's Research: Cynthia Liutkus-Pierce, Brian W Zimmer, Sarah K Carmichael, William McIntosh, Alan Deino, *Seth M Hewitt, *Katelyn J McGinnis, *Travis Hartney, James Brett, Sara Mana, Daniel M Deocampo, Brian G Richmond, Kevin Hatala, William Harcourt-Smith, Briana Pobiner, Adam Metallo, and Vince Rossi, 2016, Radioisotopic age, formation, and preservation of Late Pleistocene human footprints at Engare Sero, Tanzania, Palaeogeography, Palaeoclimatology, Palaeoecology, v. 463, p. 68-82 (doi: 10.1016/j.palaeo.2016.09.019) 

Paige Anderholm '18 - Independent Study (Political Science with Geology minor)

Mn oxides in acid mine drainage from Ore Knob, Ashe County, NC.

Benjy Strauss '16 - Independent Study (Geology)

Petrogenesis of the Greer Hollow ultramafic suite, northwestern NC

Mara Cloutier '16 - Master's Thesis (Biology)

Microbial community analysis coupled with geochemical studies reveal factors affecting biotic Mn(II) oxidation in situ (co-advised with Dr. Suzanna Bräuer)


Papers resulting from Mara's Research: *Mara LC Cloutier, Sarah K Carmichael, Michael A Carson, Michael D Madrich, and Suzanna Bräuer, 2017, Carbon quantity and quality drives variation in cave microbial communities and regulates Mn(II) oxidation, Biogeochemistry, v. 134, p. 77–94 (DOI: 10.1007/s10533-017-0343-8) 

Cameron Batchelor '15 - Independent Study and Senior Thesis (Geology)

Constraining the Ages of Late Devonian Extinction Events in the Central Asian Orogenic Belt (CAOB): U-Pb Geochronology and Igneous Petrology (co-advised with Dr. Johnny Waters and Dr. Drew Coleman, UNC-Chapel Hill)


Papers resulting from Cameron's Research: Suttner, Thomas J., Kido, Erika, Ariunchimeg, Yarinpil, Sersmaa, Gonchigdorj, Waters, Johnny A., Carmichael, Sarah K., *Batchelor, Cameron J., *Ariuntogos, Munkhjargal, *Hušková, Aneta, Slavik, Ladislav, Valenzuela-Ríos, José I., Liao, Jau-Chyn, and Gatovsky, Yury A., 2020, Conodonts from Late Devonian island arc settings (Baruunhuurai Terrane, western Mongolia), Palaeogeography, Palaeoclimatology, Palaeoecology (DOI: 10.1016/j.palaeo.2019.03.001)
Carmichael, S.K., Waters, J.A., *Batchelor, C.J., Coleman, D., Suttner, T.J., Kido, E., *Moore, L.M., and Chadimova, L., 2016, Climate instability and tipping points in the Late Devonian: Detection of the Hangenberg Event in an open oceanic island arc in the Central Asian Orogenic Belt, Gondwana Research, v. 32, p. 213-231 (DOI:10.1016/j.gr.2015.02.009). - click here for institutional repository copy with supplemental data  

Joshua Feierstein '15 - Independent Study (Geology)

2014-2015 - Development of SQL server for the DAGGER database (http://dagger.appstate.edu)

2012-2014 - Crystallinity and biosignatures preserved in cultured Mn oxides


Papers resulting from Josh's Research: Sarah K Carmichael, Daniel H Doctor, Crystal G Wilson, *Joshua Feierstein, Ryan J McAleer, 2017, New insight into the origin of manganese oxide ore deposits in the Appalachian Valley and Ridge of northeastern Tennessee and northern Virginia, USA, Geological Society of America Bulletin, v.129, p. 1158-1180 (DOI: 10.1130/B31682.1) - click here for institutional repository copy with supplemental data 

Matthew Wilson '16 - Independent Study (Geology)

Mineralogy of the sediments surrounding the Late Devonian Annulata Event in the CAOB (co-advised with Dr. Johnny Waters)

Iris Ferris - Independent Study (Geology)

Microbialite textures in Late Devonian rocks from Mongolia (co-advised with Dr. Johnny Waters)

Casey Weber - Independent Study (Geology)

Organic Geochemistry of Late Devonian rocks from the CAOB (pilot study) (co-advised with Dr. Johnny Waters)

Bryan Zorn '14 - Masters Thesis (Biology)

Illumina Sequencing of Fungal Assemblages and Manganese Biomineralization Reveals Compositional Shifts as a Result of Nutrient Loading within Cave Sediments (co-advised with Dr. Suzanna Bräuer)


Papers resulting from Bryan's Research: Carmichael, S.K., *Zorn, B.T., Santelli, C.M., *Roble, L.A., *Carmichael, M.J., and Bräuer, S.L., 2015, Nutrient input influences fungal community composition and size and can stimulate Mn(II) oxidation in caves, Environmental Microbiology Reports, v. 7, no. 4, p. 592-605 (DOI:10.1111/1758-2229.12291) - click here for institutional repository copy with supplemental data

L. McCain Moore '15 - Independent Study (Geology)

Detection of the Hangenberg Event in the Heishantou Formation, northwestern China (co-advised with Dr. Johnny Waters)


Papers resulting from McCain's Research: Carmichael, S.K., Waters, J.A., *Batchelor, C.J., Coleman, D., Suttner, T.J., Kido, E., *Moore, L.M., and Chadimova, L., 2016, Climate instability and tipping points in the Late Devonian: Detection of the Hangenberg Event in an open oceanic island arc in the Central Asian Orogenic Belt, Gondwana Research, v. 32, p. 213-231 (DOI:10.1016/j.gr.2015.02.009). - click here for institutional repository copy with supplemental data  

Sonia Sanchez '14 - Independent Study (Geology)

Characterization of the Zhulumute Formation, northwestern China (co-advised with Dr. Johnny Waters)

Aubry DeReuil '13 - Independent Study and Senior Thesis (Geology)

Sedimentation, Geochemistry, and Mineralogy across the Frasnian-Fammenian Boundary, northwestern China (co-advised with Dr. Johnny Waters)


Papers resulting from Aubry's Research: Carmichael, Sarah K., Waters, Johnny A., Suttner, Thomas J., Kido, Erika, and *DeReuil, Aubry, 2014, A New Model for the Kellwasser Anoxia Events (Late Devonian): Shallow Water Anoxia in an Open Oceanic Setting in the Central Asian Orogenic Belt, Palaeogeography, Palaeoclimatology, Palaeoecology, v. 399, p. 394-403 - click here for institutional repository copy with supplemental data 

Oliver Burns '14 - Independent Study (Geology)

The role of geologic substrate in biomineralization of Mn oxides in caves

Mary Jane Carmichael '12 - Masters Thesis (Biology)

Geomicrobiology of Ferromanganese Deposits in Caves of the Upper Tennessee River Basin (co-advised with Dr. Suzanna Bräuer)


Papers resulting from Mary Jane's Research: Carmichael, S.K., *Zorn, B.T., Santelli, C.M., *Roble, L.A., *Carmichael, M.J., and Bräuer, S.L., 2015, Nutrient input influences fungal community composition and size and can stimulate Mn(II) oxidation in caves, Environmental Microbiology Reports, v. 7, no. 4, p. 592-605 (DOI:10.1111/1758-2229.12291) - click here for institutional repository copy with supplemental data
Carmichael, Sarah K., *Carmichael, Mary Jane, *Roble, Leigh Anne, *Johnson, Krissy, Gao, Yongli, and Bräuer, Suzanna, 2013, Evidence of sustained anthropogenic impact in Carter Saltpeter Cave, Carter County, Tennessee and the potential effects on manganese cycling, Journal of Cave and Karst Science, v. 73, no. 3, p. 184-209 - click here for institutional repository copy with supplemental data
*Carmichael, Mary Jane, Carmichael Sarah K., Santelli, Cara, *Strom, Amanda C., and Bräuer, Suzanna L., 2013, Mn(II)-oxidizing bacteria are abundant and environmentally relevant members of ferromanganese deposits in Eastern Tennessee Caves, Geomicrobiology Journal, v. 13, no. 9, p. 779-800 (DOI: 10.1080/01490451.2013.769651 ) (open access)

Leigh Anne Roble '12 - Independent Study and Senior Thesis (Geology)

Manganese Oxidation by Fungi in Karst Environments

Papers resulting from Leigh Anne's Research: Carmichael, Sarah K., *Carmichael, Mary Jane, *Roble, Leigh Anne, *Johnson, Krissy, Gao, Yongli, and Bräuer, Suzanna, 2013, Evidence of sustained anthropogenic impact in Carter Saltpeter Cave, Carter County, Tennessee and the potential effects on manganese cycling, Journal of Cave and Karst Science, v. 73, no. 3, p. 184-209 - click here for institutional repository copy with supplemental data
Carmichael, S.K., *Zorn, B.T., Santelli, C.M., *Roble, L.A., *Carmichael, M.J., and Bräuer, S.L., 2015, Nutrient input influences fungal community composition and size and can stimulate Mn(II) oxidation in caves, Environmental Microbiology Reports, v. 7, no. 4, p. 592-605 (DOI:10.1111/1758-2229.12291) - click here for institutional repository copy with supplemental data

Kaylee Barket '13 - Independent Research (Geology)

FT-IR analysis of nepheline water content in volcanic carbonatites, northern Tanzania.

H. Cody Amakali '12 - Independent Research (Geology)

Mn oxide and Pb-Zn deposits and their geochemical tracers in the Shady Dolomite in the Austinville District, southwest Virginia.

Seth Hewitt '11 - Senior Thesis - second reader (Geology)

Petrographic and geochemical analysis of the volcanic region surrounding the Lake Natron Homo sapiens footprint site, northern Tanzania (primary advisor: Dr. Cynthia Liutkus-Pierce)


Papers resulting from Seth's Research: Cynthia Liutkus-Pierce, Brian W Zimmer, Sarah K Carmichael, William McIntosh, Alan Deino, *Seth M Hewitt, *Katelyn J McGinnis, *Travis Hartney, James Brett, Sara Mana, Daniel M Deocampo, Brian G Richmond, Kevin Hatala, William Harcourt-Smith, Briana Pobiner, Adam Metallo, and Vince Rossi, 2016, Radioisotopic age, formation, and preservation of Late Pleistocene human footprints at Engare Sero, Tanzania, Palaeogeography, Palaeoclimatology, Palaeoecology, v. 463, p. 68-82 (doi: 10.1016/j.palaeo.2016.09.019)