Annette Summers Engel
Donald and Florence Jones Professor of Aqueous Geochemistry
University of Tennessee at Knoxville
Department of Earth and Planetary Sciences
Edited Books
Engel, A.S., and Hatcher, Jr., R.D. (editors) (2018) Geology at Every Scale:
Field Excursions for the 2018 GSA Southeastern Section Meeting in Knoxville,
. Geological Society of America Field Guide 50, 209 p.

Engel, A.S. (editor) 2015. Microbial Life of Cave Systems. Berlin,
Walter de Gruyter GmbH, 335 pp.

   This book won the prize for "the most significant publication about cave
   or a karst-related topic" at the International Union of Speleology congress
   in Prenith, Australia, in 2017.
Klimchouk, A., Sasowsky, I.D., Mylroie, J., Engel, S.A., Engel, A.S. (editors) (2014) Hypogene Cave Morphologies. Karst Waters Institute Special Publication 18: Leesburg, Virginia, 111 p.
Engel, A.S., Engel, S.A., Moore, P.J., and DuChene, H. (editors) (2011) Carbonate Geochemistry: Reactions and Processes in Aquifers and Reservoirs. Karst Waters Institute Special Publication 16: Leesburg, Virginia, 84 p.
Engel, A.S., and Engel, S.A. (editors) (2009) Select Field Guides to Cave and Karst Lands of the United States. Karst Waters Institute Special Publication 15: Leesburg, VA, 184 p.
Peer-reviewed Journal Articles and Scholarly Book Chapters
2018 - 2019
(67) Engel, A.S. (in press) Chemolithoautotrophy, in Culver, D., Pipan, T., W. White (eds). Encyclopedia of Caves, 3rd edition.

(66) Engel, A.S. (In press) Microbes, in Culver, D., Pipan, T., W. White (eds). Encyclopedia of Caves, 3rd edition.

(65) Mulec, J., and Engel, A.S. (2019) Karst spring microbial diversity differs across an oxygen-sulphide ecocline and reveals potential for novel taxa discovery. Acta Carsologica. 48(1), doi:

(64) Lim, S.J., Davis,B.G.,Gill, D.E., Walton, J., Nachman, E., Engel, A.S., Anderson, L.C., Campbell, B.J. (2018) Taxonomic and functional heterogeneity of the gill microbiome in a symbiotic coastal mangrove lucinid species. ISME Journal. Online Dec 05, 2018 .

(63) Engel, A.S., Liu, C., Paterson, A.T., Anderson, L.C., Turner, R.E., Overton, E.B. (2017) Salt marsh bacterial communities before and after the Deepwater Horizon oil spill. Applied and Environmental Microbiology. 83:e00784-17; doi: 10.1128/AEM.00784-17

(62) Dorigo, L., Squartini, A., Toniello, V., Dreon, A.L., Pamio, A., Concina, G., Simonutti, V., Ruzzier, E., Perreau, M., Engel, A.S., Gavinelli, F., Martinez-Sanudo, I., Mazzon, L., and Paoletti, M. (2017) Cave hygropetric beetles and their feeding behavior, a comparative study of Cansiliella servardeii and Hadesia asamo (Coleoptera: Leiodidae, Chelevinae, Leptodirini). Acta Cartsologica 46 (2-3) DOI:
(61) Niemiller, M.L., Zigler, K.S., Ober, K.A., Carter, E.T. Engel, A.S., Moni, G., Philips, T.K., Stephen, C.D.R. (2017) Rediscovery and conservation status of six  short-range endemic Pseudanophthalmus cave beetles (Carabidae: Trechini). Insect Conservation and Biodiversity. 10:495-501. doi:10.11/icad.12263

(60) Keenan, S.W. , Engel, A.S. (2017) Reconstructing diagenetic conditions of the Gray Fossil Site, Tennessee, USA. Palaeogeography, Palaeoclimatology, Palaeoecology. 471:48-57.

(59) Keenan, S.W., Engel, A.S. (2017) Early diagenesis and recrystallization of bone. Geochimica et Cosmochimica Acta. 196: 209-223. DOI:10.1016/j.gca.2016.09.033 .

(58) Plenge, M.F., Engel, A.S., Omelon, C.R., Bennette, P.C. (2017) Thermophilic archaeal diversity and methanogenesis from El Tatio Geyser Field, Chile. Geomicrobiology Journal,  DOI: 10.1080/01490451.2016.1168496

(57) Yun et al. (2016) The relationship between pH and bacterial communities in a single karst ecosystem and its implications for soil acidification. Frontiers in Microbiology - Extreme Microbiology.

(56) Niemiller, M.L., Zigler, K.S., Hart, P.B., Kuhajda, B.R., Armbruster, J.W., Ayala, B.N., Engel, A.S. (2016) First record of a stygobiotic fish (Percopsiformes: Amblyopsidae: Typhlichthys) from the Appalachians karst region in the eastern United States. Subterranean Biology. 20: 39-50. doi: 10.3897/subtbiol.20.9693

(55) Hutchins, B., Engel, A.S., Nowlin, W., Schwartz, B. (2016) Chemolithoautotrophy supports macroinvertebrate food webs and affects diversity and stability in groundwater communities. Ecology,  DOI: 10.1890/15-1129.1

(54) Niemiller, M.L., Zigler, K.S., Stephen, C.D.R., Carter, E.T., Paterson, A.T., Taylor, S.J., Engel, A.S. (2016) Vertebrate fauna in caves of the east Tennessee Valley and Ridge region (USA). Journal of Cave and Karst Studies. DOI:   Includes cover photograph.

(53) Zigler, K.S., Kuhajda, B.R., Ayala, B.N., Niemiller, M.L., Engel, A.S. (2015) First observation of Southern Cavefish (Typhlichthys subterraneus) east of the Cumberland Plateau. Bulletin of the Georgia Speleological Society 2015: 9-11. (includes cover)

(52) Keenan, S.W., Engel, A.S., Roy, A., Bovenkamp, G.L. (2015) Evaluating the consequences of diagenesis and fossilization on bioapatite lattice structure and composition. Chemical Geology.  doi:10.1016/j.chemgeo.2015.08.005  
(51) Paterson, A.T., Engel, A.S. (2015) Predicting bacterial diversity in caves associated with sulfuric acid speleogenesis, in Engel, A.S. (ed.) Microbial Life of Cave Systems. Berlin: De Gruyter, 193-214.
(50) Engel, A.S. (2015) Bringing microbes into focus for cave science: An introduction, in Engel, A.S. (ed.) Microbial Life of Cave Systems. Berlin, De Gruyter, 1-22.
(49) Brannen-Donnelly, K., Engel, A.S. (2015) Bacterial diversity differences along an epigenic cave stream reveal evidence of community dynamics, succession, and stability. Frontiers in Microbiology. July, vol. 6; doi:10.3389/fmicb.2015.00729 .
(48) Turner, R.E., Overton, E.B., Ashton, B.M., Miles, M.S., McClenachan, G., Hooper-Bui, L., Engel, A.S., Swenson, E.M., Lee, J.M., Milan, C.S., Gao, H. (2014) Distribution and recovery trajectory of Macondo (Mississippi Canyon 252) oil in Louisiana salt marshes. Marine Pollution Bulletin. 87:57-67.
(47) Headd, B., Engel, A.S. (2014) Congruency among bacterial communities from terrestrial sulfidic springs. Frontiers in Microbiology. 5:473 DOI: 10.3389/fmicb.2014.00473
(46) Hooper-Bui, L., Rabalais, N.N., Engel, A.S., Turner, R.E., McClenachan, G., Robert, B., Overton, E.B., Justic, D., Strudivant, K., Brown, K., Conover, J. (2014) Overview of Research into the coastal effects of the Macondo Blowout from the Coastal Waters Consortium: A GoMRI Consortium. International Oil Spill Conference Proceedings. American Petroleum Institute. 1:604-617.

(45) Engel, A.S., Gupta, A. (2014) Regime shift in sandy beach microbial communities following Deepwater Horizon oil spill remediation efforts. PLoS One. 9(7): e102934, DOI:10.1371/journal.pone.0102934
(44) Engel, A.S., Bovenkamp, G.L., Prange, A., Hormes, F.J. (2014) In situ speciation of sulfur vapors using X-ray absorption near edge structure spectroscopy. Chemical Geology. 380: 1-6. DOI: 10.1016/j.chemgeo.2014.04.019
(43) Yin, J., Rekepalli, B., Patel, P. Drennen, C., Engel, A.S. (2014) Instrumenting genomic sequence analysis pipeline mothur on shared memory architecture. XSEDE ‘14 Proceedings of the 2014 Annual Conference on Extreme Science and Engineering Discovery Environment, ACM, New York, New York; DOI:10.1145/2616498.2616505
(42) Hutchins, B., Schwartz, B., Engel, A.S. (2013) Environmental controls on organic matter production and transport across surface-subsurface and geochemical boundaries in the Edwards Aquifer, Texas, USA. Acta Carsologica 42/2-3: 245–259.
(41) Keenan, S., Engel, A.S., Elsey, R.M. (2013) The alligator gut microbiome and implications for archosaur symbiosis. Scientific Reports. 3:2877. DOI:10.1038/srep02877
(40) Engel, A.S., Paoletti, M., Beggio, M., Dorigo, L., Pamio, A., Gomiero, T., Furlan, C., Brilli, M., Bertonie, R., Dreon, A.L. (2013) Comparative microbial community composition from secondary carbonate (moonmilk) deposits: implications for the Cansiliella servadeii cave hygropetric food web. International Journal of Speleology.  42: 181-192. DOI: 10.5038/1827-806X.42.3.2
(39) Paoletti, M.G., Mazzon, L., Sanudo, I.Z., Simonato, M., Beggio, M., Dreon, A.L., Pamio, A., Brilli, M., Dorigo, L., Engel, A.S., Tondello, A., Baldan, B., Concheri, G., Squartini, A. (2013) A unique midgut-associated bacterial community hosted by the cave beetle Cansiliella servadeii (Coleoptera: Leptodirini) reveals parallel phylogenetic divergences from universal gut-specific ancestors. BMC Microbiology. 13:129. DOI:10.1186/1471-2180-13-129
(38) Headd, B., Engel, A.S. (2013) Evidence for niche partitioning revealed by the distribution of sulfur oxidation genes collected from areas of a terrestrial sulfidic spring with differing geochemical conditions. Applied and Environmental Microbiology. 79: 1171-1182. DOI:10.1128/AEM.02812-12
(37) Gray, C.J., Engel, A.S. (2013) Microbial diversity and impact on carbonate geochemistry across a changing geochemical gradient. ISME Journal. 7: 325:337. DOI:10.1038/ismej.2012.105
(36) Engel, A.S., Johnson, L.R., Porter, M.L. (2013) Arsenite oxidase gene diversity among Chloroflexi and Proteobacteria from El Tatio Geyser Field, Chile. FEMS Microbiology Ecology. 83: 745–756. DOI: 10.1111/1574-6941.12030
(35) Lee, N.M., Liebl, W.E., Engel, A.S., Porter, M.L. (2013) Cave biofilm metagenomics. In: Nelson K. (ed.) Encyclopedia of Metagenomics: Springer-Verlag Berlin Heidelberg, SpringerReference DOI: 10.1007/978-1-4614-6418-1_718-2
(34) Green-Garcia, A.M., Engel, A.S. (2012) Bacterial diversity of siliciclastic sediments in a Thalassia testudinum meadow and the implications for Lucinisca nassula chemosymbiosis. Estuarine, Coastal and Shelf Science. 112: 153-16.
(33) Rossmassler, K., Engel, A.S., Twing, K. Hanson, T.E, Campbell, B.J (2012) Drivers of Epsilonproteobacteria community composition in sulfidic caves and springs. FEMS Microbiology Ecology. 79:421-432. DOI:10.1111/j.1574-6941.2011.01231.x
(32) Engel, A.S. (2012) Microbes, in Culver, D. and W. White, (eds.) Encyclopedia of Caves. 2nd Edition, p. 490-499. 
(31) Engel, A.S. (2012) Chemoautotrophy, in Culver, D. and W. White, (eds.) Encyclopedia of Caves. 2nd Edition. p. 125-134. 
(30) Lee, N.M., Meiginger, D.B., Aubrecht, R., Kovacic, L., Saiz-Jimenez, C. Baskar, S.R., Schleifer, K.-H., Liebl, W., Porter, M.L., Engel, A.S. (2012)  Life in caves, in Bell, E. (ed.) Life at Extremes: Environments, Organisms and Strategies for Survival. CAB Publishing. p. 302-344. 
(29) Engel, A.S., Randall, K.W. (2011) Experimental evidence for microbially-mediated carbonate dissolution from the saline water zone of the Edwards Aquifer, Central Texas. Geomicrobiology Journal. 28(3): 313-327.
(28) Paoletti, M.G., Beggio, M., Dreon, A.L., Pamio, A., Gomiero, T., Brilli, M., Dorigo L., Concheri G., Squartini A., Engel, A.S. (2011) A new foodweb based on microbes in calcitic caves: The Cansiliella (beetles) case in Northern Italy. International Journal of Speleology. 40: 45-52. DOI:10.5038/1827-806X.40.1.6.
(27) Engel, A.S. (2011) Karst ecosystems, in Reitner, J., and Thiel, V. (eds.), Encyclopedia of Geobiology, Springer Encyclopedia of Earth Sciences Series (EESS, formerly Kluwer Edition), Berlin Encyclopedia of Earth Sciences Series, pp. 521-53. DOI: 10.1007/978-1-4020-9212-1. (peer-reviewed)
(26) Engel, A.S., Meisinger, D.B., Porter, M.L., Payn, R., Schmid, M., Stern, L.A., Schleifer, K.-H., Lee, N.M. (2010) Linking phylogenetic and functional diversity to nutrient spiraling in microbial mats from Lower Kane Cave (USA). ISME Journal. 4:98–110; DOI:10.1038/ismej.2009.91.
(25) Birdwell, J.E., Engel, A.S. (2010) Characterization of dissolved organic matter in cave and spring waters using UV-Vis absorbance and fluorescence spectroscopies. Organic Geochemistry. 41: 270-280.
(24) Engel, A.S. (2010) Microbial diversity of cave ecosystems, in Barton, L., Mandl, M., and Loy, A. (eds.), Geomicrobiology: Molecular & Environmental Perspectives, Springer. p. 219-238. DOI:10.1007/978-90-481-9204-5_10. 
(23) Engel, A.S., Engel, S.A. (2009) A field guide for the karst of Carter Caves State Resort Park and the surrounding area, northeastern Kentucky, in Engel, A.S. and Engel, S.A. (editors) Select Field Guides to Cave and Karst Lands of the United States: Twenty years of science and exploration. Karst Waters Institute Special Publication 15: Leesburg, Virginia, p. 87-109.
(22) Birdwell, J.E., Engel, A.S. (2009) Variability in terrestrial and microbial contributions to dissolved organic matter fluorescence in the Edwards Aquifer, Central Texas. Journal of Cave and Karst Studies. 71: 144-156. (includes published cover photograph for the issue)
(21) Landrum, J.T., Bennett, P.C., Engel, A.S., Alsina, M.CG, Pastén, P., Milliken, K. (2009) Partitioning geochemistry of arsenic and antimony, El Tatio Geyser Field, Chile. Applied Geochemistry. 24: 664-676. DOI:10.1016/j.apgeochem.2008.12.024   
(20) Porter, M.L.*, Engel, A.S.*, Kane, T.C.+, Kinkle, B.K. (2009) Productivity-diversity relationships from chemolithoautotrophically based sulfidic karst systems. International Journal of Speleology. 38(1): 27-40 (*equal contribution; +deceased).
(19) Engel, A.S. (2009) Sulfur-rich karst systems, in Palmer, A.N. and Palmer, M.V. (eds.), Caves and Karst of the USA. National Speleological Society: Huntsville, Alabama, p. 404.
(18) Porter, M.L., Engel, A.S. (2008) Diversity of uncultured Epsilonproteobacteria from terrestrial sulfidic caves and springs. Applied and Environmental Microbiology. 74(15): 4973-4977. DOI:10.1128/AEM.02915-07
(17) Porter, M.L., Engel, A.S. (2008) Balancing the conservation needs of sulphidic caves and karst with tourism, economic development, and scientific study: Cave and Karst Science. 35:19-24.
(16) Engel, A.S., Northup, D.E. (2008) Focus group on caves and karst as model systems in geomicrobiology, in Martin, J. and White, W.B. (eds)., Frontiers in Karst Research, Karst Waters Institute Special Publication 13: Leesburg, Virginia, p. 90-95.
(15) Engel, A.S., Northup, D.E. (2008) Caves and karst as model systems for advancing the microbial sciences, in Martin, J. and White, W.B. (eds.), Frontiers in Karst Research, Karst Waters Institute Special Publication 13, Leesburg, Virginia: 37-48. 
(14) Engel, A.S. (2007) Observations on the biodiversity of sulfidic karst habitats. Journal of Cave and Karst Studies. 69(1): 187-206.
(13) Engel, A.S., Lichtenberg, H., Prange, A., Hormes, J. (2007) Speciation of sulfur from naturally-occurring, filamentous microbial mats from sulfidic cave springs using x-ray absorption near edge spectroscopy. FEMS Microbiology Letters. 269(1): 54-62. DOI:10.1111/j.1574-6968.2006.00600.x.
(12) Meisinger, D.B.*, Zimmermann, J.*, Ludwig, W., Schleifer, K.-H., Wanner, G., Schmid, M., Bennett, P.C., Engel, A.S., and Lee, N. (2007) In situ detection of novel Acidobacteria in microbial mats from a chemoautotrophically-based cave ecosystem. Environmental Microbiology. 9(6): 1523-1534. (* equal contribution) DOI:10.1111/j.1462-2920.2007.01271.x. (included published cover of the issue)
(11) Bennett, P.C., Engel, A.S. (2007) Microbial sulfur cycling in a sulfidic cave, in Bullen, T.D., and Wang, Y. (eds.), Water-Rock Interaction, Taylor & Francis Group, London: 853-858.
(10) Campbell, B.J.*, Engel, A.S.*, Porter, M.L., and Takai, K. (2006) The versatile Epsilon-proteobacteria: Key players in sulphidic habitats. Nature Reviews Microbiology. 4:458-468. (* equal contribution)
(9) Phoenix, V.R., Bennett, P.C., Engel, A. S., Tyler, S.W., and Ferris F.G. (2006) Chilean high-altitude hot spring sinters: a model system for UV screening mechanisms by early Precambrian cyanobacteria. Geobiology. 4: 15-28.
(8) Bennett, P.C., Engel, A.S., Roberts, J.A. (2006) Counting and imaging bacteria on mineral surfaces, in Maurice, P.A., Warren, L.A. (eds.), Methods of Investigating Microbial-Mineral Interactions, CMS Workshop Lectures, Vol. 14, The Clay Mineral Society, Chantilly, Virginia: 37-77.
(7) Engel, A.S. (2005) Chemoautotrophy, in Culver, D. and W. White, (eds.) Encyclopedia of Caves. p. 90-102. 
(6) Bennett, P.C., and Engel, A.S. (2005) Microbial contributions to karstification, in Gadd, G.M., Semple, K.T., and Lappin-Scott, H.M. (eds.), Micro-organisms and Earth Systems – Advances in Geomicrobiology, Society for General Microbiology (SGM) Symposium 65, Cambridge University Press: 345-363. (peer-reviewed)
(5) Engel, A.S., Porter, M.L., Stern, L.A., Quinlan, S., Bennett, P.C. (2004) Bacterial diversity and ecosystem function of filamentous microbial mats from aphotic (cave) sulfidic springs dominated by chemolithoautotrophic “Epsilonproteobacteria.” FEMS Microbiology Ecology. 51: 31-53.
(4) Engel, A.S., Stern, L.A., and Bennett, P.C. (2004) Microbial contributions to cave formation: new insights into sulfuric acid speleogenesis. Geology. 32(5): 369-372.
(3) Engel, A.S., Lee, N., Porter, M.L., Stern, L.A., Bennett, P.C., and Wagner, M. (2003) Filamentous “Epsilonproteobacteria” dominate microbial mats in sulfidic caves. Applied and Environmental Microbiology. 69(9): 5503-5511.
(2) Engel, A.S., Porter, M.L., Kinkle, B.K., and Kane, T.C. (2001) Ecological assessment and geological significance of microbial communities from Cesspool Cave, Virginia. Geomicrobiology Journal. 18:259-274.
(1) Vlasceanu, L., Sarbu, S., Engel, A.S., and Kinkle, B.K. (2000) Acidic, cave-wall biofilms from the Frasassi Caves, Italy. Geomicrobiology Journal. 17:125-139.  
Edited, editor-reviewed, scholarly conference proceedings, & other publications
(24) Engel, A.S., Niemiller, M.L. (2018) Landowner’s guide to biological resources and biodiversity in Tennessee caves. University of Tennessee Institute of Agriculture Extension publication W453-D. 

(23) Engel, A.S., Niemiller, M.L., Zigler, K.S., Stephen, C.D.R., Carter, E.T., Paterson, A.T., Keenan, S.W., Taylor, S.J. (2017) Invertebrate and vertebrate cave fauna records for the Appalachian Valley and Ridge, in Moore K., White S. (eds). Proceedings of the 17th International Congress of Speleology, July, Sydney, Australia, Volume 1, Australian Speleological Federation Inc. Sydney, p. 82-86.

(22) Keenan, S.W., Paterson, A.T., Niemiller, M.L., Slay, M.E., Clark, S.A., Engel, A.S. (2017) Observations of the first stygobiont snail (Hydrobiidae, Fontigens sp.) in Tennessee, in Moore K., White S. (eds). Proceedings of the 17th International Congress of Speleology, July, Sydney, Australia, Volume 1, Australian Speleological Federation Inc. Sydney.

(21) Engel, A.S. (2013) The caves that microbes built – The frontier of cave and karst science, in Filippi, M. and Bosák, P. (eds.). Proceedings of the 16th International Congress of Speleology, July 21-28 Brno, Czech Republic. Vol. 1, p. 22-25. Extended abstract for invited plenary lecture.
(20) Engel, A.S. (2013) Microbial processes in sulfidic hypogene karst, in Filippi, M. and Bosák, P. (eds.). Proceedings of the 16th International Congress of Speleology, July 21-28 Brno, Czech Republic. Vol. 1, p.391-394.
(19) Brown, T., Engel, A.S., Brannen, K.M., Birdwell, J.E. (2011) Estimating aquifer contributions to carbon cycle budgets based on dissolved organic matter characterization in karts aquifers, in Engel, A.S., Engel, S.A., Moore, PJ, and DuChene, H. (eds.), Carbonate Geochemistry: Reactions and Processes in Aquifers and Reservoirs, Karst Waters Institute Special Publication 16: Leesburg, Virginia, p. 8-9.
(18) Engel, A.S. (2010) Incorporating the Deepwater Horizon oil spill into geomicrobiology courses. National Association of Geoscience Teachers e-News Magazine. Sept. 2010.
(17) Engel, A.S. (2010) Book Review - Cave Biology: Life in Darkness. Aldemaro Romero: Integrative and Comparative Biology. 50 (4): 689-691. doi: 10.1093/icb/icq067 First published online: June 4, 2010.
(16) Brannen, K.M., Engel, A.S., and Birdwell, J.E. (2009) Tracing the origins of chromophoric dissolved matter in karst aquifers, in White, W.B. (ed.), Proceedings of the 15th International Congress of Speleology, vol. 1, symposia part 1, p. 354-359.
(15) Paoletii, M.., Beggio, M., Pamio, A., Gomiero, T., Brilli, M., Dreon, A.L., Toniello, V., and Engel, A.S. (2009) Comparison of three moonmilk cave habitats associated with troglobitic beetles, in White, W.B. (ed.), Proceedings of the 15th International Congress of Speleology, vol. 1, symposia part 1, p. 400-403.
(14) Engel, A.S., Meisinger, D.B., Porter, M.L., Schmid, M., and Lee, N.M. (2009) Caves as model systems for the evolution of a complex biosphere in a chemolithoautotrophic subsurface, Special Issue: Abstracts from the Eighth European Workshop on Astrobiology (EANA): Origins of Life and Evolution of Biospheres DOI:10.1007/s11084-008-9155-0.
(13) Engel, A.S. and K.W. Randall (2008) Microbially enhanced carbonate dissolution in karst aquifers, in Sasowsky, I.D., Feazel, C.T., Mylroie, J.E., Palmer, A.N., and Palmer, M.V. (eds.), Karst from Recent to Reservoirs, Karst Waters Institute Special Publication 14: Leesburg, Virginia, p. 52-56.
(12) Engel, A.S., Bennett, P.C. (2008) Lower Kane Cave, Wyoming: Where biology and geology meet, in Rhinehart, R. (ed.), National Speleological Society Rocky Mountain Section Regional Field Guide, p. 43-57.
(11) Stern, L.A., Engel, A.S., Bennett, P.C., and Porter, M.L. (2002) Subaqueous and subaerial speleogenesis in a sulfidic cave, in Martin, J.B., Wicks, C.M., and Sasowsky, I.D. (eds.),  Hydrogeology and Biology of Post- Paleozoic Carbonate Aquifers, Karst Waters Institute Special Publication 7: Leesburg, Virginia, p. 89-91.
(10) Engel, A.S., Bennett, P.C., and Stern, L.A. (2001) Biogeochemical diversity of microbial mats from Lower Kane Cave, Wyoming, USA, in Weber, J., Jamroz, E., Drozd, J., and Karczewska, A. (eds.) Biogeochemical Processes and Cycling of Elements in the Environment. 15th Int Symposium of Environmental Biogeochemistry, Wroclaw, Poland: p. 135-136.
(9) Engel, A.S. (2000) Microbially-enhanced weathering in subsurface environments: Sulfur-oxidizing bacteria and the cave environment, in Onac, B. and Tamaş, T. (eds.) Karst Studies and Problems: 2000 and Beyond. Friends of Karst Special Meeting. Cluj, Romania: p. 130-134.
(8) Summers, A. (1999) Don’t drink the water. Electric Caver. 36(3):7.
(7) Engel, S., Summers Engel, A. (1998) Great Saltpetre Cave, Rockcastle County, Kentucky: a geology and archeology field guide. Electric Caver. 35(3):5-12.
(6) Summers Engel, A., Sarbu, S., Badescu, A., Lascu, C., Sasowsky, I., and W. Huff. (1997) A study of cave sediment from Movile Cave, Southern Dobrogea, Romania. Proceedings of the 12th International Congress of Speleology, Las Chaux-de-Fonds, Switzerland. Vol. 1: p. 25-28.
(6) Krekeler, M.P.S., Summers Engel, A., Engel, S., Mixon, D., and M. Ragsdale. (1997) Sedimentology, clay mineralogy, and geochemistry of cave sediment from Hard Baker Cave, Rockcastle County, Kentucky, USA. Proceedings of the 12th International Congress of Speleology, Las Chaux-de-Fonds, Switzerland. Vol. 1: p. 21-24.
(5) Summers, A. (1996) Small, but interesting caves in Carter County, Kentucky. SpeleoDigest 1995: 119-121.
(4) Summers, A. (1995) Sulfur bacteria in the spelean environment. Pholeos 15(2):29-39 (reprint 1996, SpeleoDigest 1995: 457-465).
(3) Summers, A. (1993) Frasier’s pits. Pholeos 13(2): 9.
(2) Summers, A. (1993) Laurel. Pholeos 13(20):18.
(1) Summers, A. (1992) Bats and public opinion. Pholeos 12(2):15-18.
Geochemistry. Geomicrobiology. Geology. Ecology.

Interdisciplinary Research at the University of Tennessee