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Dr. Stephanie Yarwood

Associate Professor

Associate Professor

Environmental Science & Technology 2208 HJ Patterson Hall College Park, Maryland 20742

I am a first generation college student who grew up liking science and the outdoors. My first job was washing dishes in a plant pathology lab for Oregon State University Extension when I was fifteen. Eventually I was hired as a student intern in a soil microbiology lab within the USDA-Agricultural Research Service. That job helped support my undergraduate college career. I earned a BA in English with the intention of becoming a nature writer, but I also loved research and teaching. My career at UMD has allowed me to do all three. In my spare time I spend time with my dogs, my horse, my vegetable garden, and my family.


Research Focus

I study the microbial ecology of soils across many different ecosystems: agricultural, wetland, forest, and urban. I seek to understand how disturbances such as wetland restoration and agricultural management impact microbial communities and what implications those changes have to nitrogen cycling, greenhouse gas emissions, and carbon storage. The broad goal of my research is to uncover information that can improve soil management and lead to a more sustainable future. 

restored wetland
Lindsay methane

Courses Taught

ENST 422 Soil Microbial Ecology (Spring)

ENST 432 Environmental Microbiology (Fall)

ENST 622 Advanced Soil Microbial Ecology (Spring)

HNUH 248B Setting the Table: The Challenges and Opportunities for Sustainable Agriculture (Fall 2023/Spring 2024)

Honors class planting vegetables in the the greenhouse.

Lab members and alumni

Post docs

Wessam Elnenr

Chih-Han Chang

Ryan Kepler

Taniya Roy Chowdhury

Mojhgan Haghnegahdar

lab group sampling

Graduate Students


Glade Dlott

Holly Bowen

Dietrich Epp Schmidt

Eni Baballari

Lindsay Wood

Alyssa Wellman Houde


Christine (Prasse) Maietta

Martina Gonzalez Mateu

Amr Keshta

Brian Scott

Humberto Castillo Gonzalez

Dietrich Epp Schmidt

Nora Hamovit



Gaelle Njonkou

Matthew Klein

Stephanie Jamis

Sara Elbeheiry

Martina Gonzalez Mateu

Nicholas Butler La-Pointe

Tamara Walsky

Eni Baballari

Zachery Bernstein

Ashley Robey

Zachary Berry

Joshua Gaimaro

Lindsay Wood

Victoria Monsaint-Queeney

Matthew Silverman

Jessica King

Donald De Alwis

Henry Wald

Jonathan Moy

Gianna Robey

Christopher Celarie

High School Interns

Ashley Robey

Amy Kuritzky

Sara Baldwin

Gianna Robey

maryland day
Another Maryland day


Oregon State University                                Soil Science         Ph.D. 2007

Whitman College                                           English                B.A. 2001

Blue Mountain Community College               Biology                A.S. 1998


James and Royal


2008    Emil Truog Award, Soil Science Society of America 

2013    Excellence in Instruction  AGNR Alumni Award

2016    Excellence in Teaching—ENST department

2016    Excellence in Mentoring—ENST department

2019    College of AGNR Paul R. Poffenberger Excellence in Teaching and Advising Award

2020    UMD Gemstone Sophomore Mentor of the Year

2023    Excellence in Teaching—ENST department



  1. Bottomley, P.J., A.E. Taylor, S.A. Boyle, S.K. McMahon, J.J. Rich, K. Cromack, D.D. Myrold. 2004.  Responses of nitrification and ammonia oxidizing bacteria to reciprocal transfers of soil between adjacent coniferous forest and meadow vegetation in the Cascade Mountains of Oregon.  Microbial Ecology 48: 500-508
  2. Boyle, S.A., J. J. Rich, P.J. Bottomley, K. Cromack, D. D. Myrold. 2006.   Reciprocal transfer effects on denitrifying community composition and activity at forest and meadow sites in the Cascade Mountains of Oregon.  Soil Biology & Biochemistry 38:870-878
  3. Boyle, S.A, R.R. Yarwood, P.J. Bottomley, D.D. Myrold.  2008.  Bacterial and fungal contributions to soil nitrogen cycling under Douglas fir and red alder at two sites in Oregon.  Soil Biology & Biochemistry 40:443-451
  4. Boyle-Yarwood, S.A., P.J. Bottomley, D.D. Myrold. 2008.  Community composition of ammonia-oxidizing bacteria and archaea in soils under stands of red alder and Douglas fir in Oregon. Environmental Microbiology 10:  2956-2965
  5. Yarwood, S.A. and E.W. Sulzman. 2008.  An activity to demonstrate soil microbial diversity in undergraduate biology classrooms.  Journal of Natural Resources and Life Science Education 37:
  6. Yarwood, S.A., D.D. Myrold, M. N. Högberg.  2009. Termination of below-ground C allocation by trees alters soil fungal and bacterial communities in a boreal forest.  FEMS Microbiology Ecology 70: 151-162
  7. Yarwood, S.A., P.J. Bottomley, D.D. Myrold.  2010.  Soil microbial communities associated with Douglas-fir and red alder stands at high- and low-productivity forest sites in Oregon, USA.  Microbial Ecology 60: 606-617
  8. Högberg, P., C. Johannisson, S. Yarwood, I. Callesen, T. Näsholm, D.D. Myrold, M.N. Högberg.  2011.  Recovery of ectomycorrhiza after ‘nitrogen saturation’ of conifer forest. New Phytologist 189:515–525
  9. Yarwood, S., E. Brewer, R. Yarwood, K. Lajtha, D. Myrold. 2013. Soil Microbe Active Community Composition and Capability of Responding to Litter Addition after 12 Years of No Inputs. Applied & Environmental Microbiology 79:1385-1392
  10. Högberg, M.N., S.A. Yarwood, D.D. Myrold. 2014. Fungal but not bacterial soil communities recover after termination of decadal nitrogen additions to boreal forest. Soil Biology & Biochemistry 72:35-438
  11. Yarwood, S., A. Wick, M. Williams, W.L. Daniels. 2015. Parent material and vegetation influence soil microbial community structure following 30-years of rock weathering and pedogenesis. Microbial Ecology 69: 383-394.
  12. Zabetakis, K.M., N. de Guzmán, A. Torrents, S. A. Yarwood. 2015. Toxicity of zero-valent iron nanoparticles to a trichloroethylene-degrading groundwater microbial community. Journal of Environmental Science & Health, Part A50: 794-805.
  13. *Prasse, C., A.H. Baldwin, S.A. Yarwood. 2015. Microbial community composition and functional capacity differ between restored and natural tidal freshwater wetlands but not plant species. Applied & Environmental Microbiology 81: 3482-3491.
  14. *Dlott, G., J. Maul, J. Buyer, S. Yarwood. 2015. Microbial rRNA:rDNA gene ratios may be unexpectedly low due to extracellular DNA preservation in soils. Journal of Microbiological Methods 115: 112-120
  15. Blaško R., L. Holm Bach, S. Yarwood, S. Trumbore, P. Högberg, M.N. Högberg. 2015. Shifts in soil microbial community structure, nitrogen cycling and the concomitant declining N availability in ageing primary boreal forest ecosystem. Soil Biology & Biochemistry 91: 200-211
  16. Tóth, Z., E. Hornung, S. Cilliers, M. Dombos, J. Kotze, H. Setälä, S.A. Yarwood, I.D. Yesilonis, R.V. Pouyat, K. Szlávecz. 2015. Preliminary results about analysis of decomposition efficiency in different quality of urban soils (GLUSEEN, Budapest). Természetvédelmi Közlemények 21: 352-361 (published in Hungarian)
  17. Pouyat, R.V., I.D. Yesilonis, M. Dombos, K. Szlávecz, H. Setälä, S. Cilliers, E. Hornung, J. Kotze and S. Yarwood. 2015. A global comparison of surface soil characteristics across five cities: A test of the urban ecosystem convergence hypothesis. Soil Science 4/5:136-145
  18. Yarwood, S.A., A.H. Baldwin, *M. Gonzalez Mateu, J.S. Buyer. 2016. Archaeal rhizosphere communities differ between the native and invasive line of the wetland plant Phragmites australis (common reed) in a Chesapeake Bay subesturary. Biological Invasions DOI 10.1007/s10530-016-1144-z
  19. +Wilson, K., +A. Perantoni, +Z. Berry, +M. Eicholtz, +Y. Tamukong, S. Yarwood, A. Baldwin. 2016. Influences of reduced iron and magnesium on growth and photosynthetic performance of Phragmites australis subsp. americanus(North American common reed).  Aquatic Botany 137: 30-38
  20. Witarsa, F., S. Lansing, S. Yarwood, *M. Gonzalez Mateu. 2016.  Incubation of Innovative Methanogenic Communities to Seed Anaerobic Digesters. Applied Microbiology and Biotechnology 100: 9795-9806
  21. *Fisher, K., S. Yarwood, B. James. 2017. Urease activity and bacterial ureC gene copy number increase with increasing pH. Geoderma 285: 1-8
  22. Pouyat, R.V., H. Setälä, K. Szlávecz, I. D. Yesilonis, S. Cilliers, E. Hornung, S. Yarwood, D. J. Kotze, M. Dombos, M. P. McGuire, and T. Whitlow.  2017. Introducing GLUSEEN: a new open access and experimental network in urban soil ecology. Journal of Urban Ecology 3 DOI: 10.1093/jue/jux002
  23. Davis, B., S. Mirsky, B. Needleman, M. Cavigelli, S. Yarwood, J. Maul. 2017.  A novel method for estimating nitrous oxide flux from single point flux measurements. Journal of Environmental Quality 46:247–254 DOI: 10.2134/jeq2016.02.0048
  24. *Epp Schmidt, D., R. Pouyat, K. Szlavecz, H. Setälä, D. J. Kotze, I. Yesilonis, S. Cilliers, E. Hornung, M. Dombos, S. Yarwood.  2017. Urbanization leads to the loss of ectomycorrhizal fungal diversity and the convergence of archaeal and fungal soil communities. Nature Ecology and Evolution DOI: 10.1038/s41559-017-0123
  25. Stevens, A. M., A. C. Smith, G. Marbach-Ad, S. A. Balcom, J. Buchner, S. L. Daniel, J. J. DeStefano, N. M. El-Sayed, K. Frauwirth, V. T. Lee, K. S. McIver, S. B. Melville, D. M. Mosser, D. L. Popham, B. E. Scharf, F. D. Schubot, R. W. Seyler, Jr., P. A. Shields, W. Song, D. C. Stein, R. C. Stewart, K. V. Thompson, Z. Yang, and S. A. Yarwood. 2017. Using a Concept Inventory to Reveal Student Thinking Associated with Common Misconceptions about Antibiotic Resistance. The Jounral of Microbiology and Biology Education 18 DOI:
  26. Muletz, C.R., G.V. DeRenzo, S. Yarwood, E.H. Campbell Grant, R.C. Fleischer, K. Lips. 2017. Antifungal bacteria on woodland salamander skin exhibit high taxonomic diversity and geographic variability. Applied and Environmental Microbiology 83:1-9
  27. Yarwood, S., M. Högberg. 2017. Soil bacteria and archaea change rapidly in the first century of Fennoscandian boreal forest development. Soil Biology and Biochemistry 114:160-167
  28. Multez-Wolz, C., S. Yarwood, E. Grant, R. Fleischer, K. Lips. 2018. Effects of host species and environment on the skin microbiome of Plethodontid salamanders. Journal of Animal Ecology 87:341-353
  29. Mueller, P. L.M. Schile-Beers, T.J. Mozdzer, G.L. Chmura, T. Dinter, Y. Kuzakov, A.V. deGroot, P. Esselink, C. Smit, A. D’Alpaos, C. Ibáñez, M. Lazarus, U. Neumeier, B.J. Johnson, A.H. Baldwin, S.A. Yarwood, D.I. Montemayor, Z. Yang, J. Wu, K. Jensen, S. Nolte. 2018. Global change effects on decomposition processes in tidal wetlands: implications from a global survey using standardized litter. Biogeosciences 15:3189-3202
  30. *Bowen, H., J.E. Maul, H. Poffenbarger, S. Mirsky, M. Cavigelli, S. Yarwood. 2018. Spatial patterns of microbial denitrification genes change in response to poultry litter placement and cover crop species in an agricultural soil. Biology and Fertility of Soils 54:769-781
  31. Szlavecz, K., C.-H. Chang, M.J. Bernard, S.L. Pitz, L. Xia, Y. Ma, M.K. McCormick, T. Filley, S.A. Yarwood, I.D. Yesilonis, C. Csuzdi. 2018. Litter quality, dispersal and invasion drive earthworm community dynaics and forest soil development. Oecologia 188:237-250
  32. Yarwood, S. 2018. The role of wetland microorganisms in plant-litter decomposition and soil organic matter formation: a critical review. FEMS Microbiology Ecology (invited review)
  33. *Maietta, C.E., +Z.A. Bernstein, +J.R. Gaimaro, J.S. Buyer, M.C. Rabenhorst, +V.L. Monsaint-Queeney, A.H. Baldwin, S. Yarwood. 2019. Aggregation but not organo-metal complexes contributed to carbon (C) storage in tidal freshwater wetland soils. Soil Science Society of America Journal 83:252-265
  34. Davis, B.W., S. Mirsky, B.A. Needleman, M.A. Cavigelli, S.A. Yarwood. 2019. Nitrous oxide emissions increase exponentially with organic N rate from cover crops and applied poultry litter. Agriculture, Ecosystems, and the Environment 272: 165-174.
  35. Yarberry, A., S. Lansing, H. Luckarift, R. Diltz, W. Mulbry, S. Yarwood. 2019. Effect of anaerobic digester inoculum preservation via lyophilization on methane recovery. Waste Management 87: 62-70
  36. *Gonzalez Mateu, M., +C.E. Park, +C.P. McAskill, A.H. Baldwin, S.A. Yarwood. 2019. Urbanization altered bacterial and archaeal composition in tidal freshwater wetlands near Washington DC, USA and Buenos Aires, Argentina. Microorganisms: doi:10.3390/microorganisms7030072
  37. *Epp Schmidt, D. J. Kotze, E. Hornung, D., H. Setälä, I. Yesilonis, K. Szlavecz, M. Dombos, S. Cilliers, R. Pouyat, T. Zsolt, S. Yarwood.  2019. Metagenomics reveals microbial adaptation to urban land-use: N catabolism, methanogenesis, and nutrient acquisition. Frontiers in Microbiology:
  38. ^Kepler, R., *D. Epp Schmidt, S. Yarwood, M. Cavigelli, K.Reddy, S. Duke, C. Bradley, M. Williams, J. Buyer, and J. Maul. 2019. Soil microbial communities in diverse agroecosystems exposed to glyphosate. Applied and Environmental Microbiology DOI: 10.1128/AEM.01744-19
  39. *Bowen, H., J. Maul, M. Cavigelli, S. Yarwood. 2020. Denitrifiers abundance and community composition linked to denitrification activity in an agricultural and wetland soil. Applied Soil Ecology 151: 103521
  40. Tóth, Z., K. Szlavecz, *D. Epp Schmidt, E. Hornung, H. Setälä, I. Yesilonis, D. Kotze, M. Dombos, R. Pouyat, S. Mishra, S. Cilliers, S. Yarwood, C. Csuzdi. 2020. Earthworm assemblages in urban habitats across biogeographical regions. Applied Soil Ecology 151: 103530
  41. *Gonzalez Mateu, M., A.H. Baldwin, J.E. Maul, S.A. Yarwood. 2020. Dark septate endophyte improves salt-tolerance of native and invasive lineages of Phragmites australis. ISME Journal
  42. *Scott, B., A. Baldwin, K. Ballentine, M. Palmer, S. Yarwood. 2020. Review: The role of organic amendments in wetland restorations. Restoration Ecology 28 (4), 776-784
  43. *Maietta, C.E., +V. Monsaint-Queeney, +L. Wood, A. Baldwin, S.A. Yarwood. 2020. Plant litter amendments in restored wetland soils altered microbial communities more than clay additions. Soil Biology and Biochemistry 147: 107846
  44. *Scott, B., S. Yarwood, A. Baldwin, C. Castañeda, B. Latorre, M. Rabenhorst. 2021. Macro and Microscopic Visual Imaging Tools to Investigate Metal Reducing Bacteria in Soils. Soil Science Society of America Journal:
  45. *Gonzalez Mateu, M., S. Yarwood, A.H. Baldwin. 2021. Positive interactions occur between Phragmites australis lineages across short term experimental nutrient   regimes. Aquatic Botany 172: 103382
  46. *Keshta, A., S. Yarwood, A. Baldwin. 2021. A new in situ method showed greater persistence of added soil organic matter in natural than restored wetlands. Restoration Ecology 29:
  47. Thapa, R., K.L. Tully, *N. Hamovit, S.A Yarwood, H.H. Schomberg, M.L. Cabrera, C. Reberg-Horton, S.B. Mirsky. 2022. Microbial processes and community structure as influenced by cover crop residue type and location during repeated dry-wet cycles. Applied Soil Ecology 172: 10.1016/j.apsoil.2021.104349
  48. *Scott, B., S. Yarwood, A. Baldwin. 2022. Adding organic matter to restore wetland soils may increase methane generation and is not needed for hydric soil development. Biogeosciences
  49. *Epp Schmidt, D., *G. Dlott, M. Cavigelli, S. Yarwood, J. Maul. 2022. Soil microbiomes in three farming systems affected more by depth than farming system. Applied Soil Ecology 173: 10.1016/j.apsoil.2022.104396
  50. Villena, O.C., J. Sullivan, E. Landa, S.A. Yarwood, A. Torrents, A. Zhang, P. T. Leisnham. 2022. The role of tire leachate in condition-specific competition and the persistence of a resident mosquito from a competitively superior invader. Insects
  51. *Epp Schmidt, D., M. Cavigelli, J. Maul, H. Schomberg, S.A. Yarwood. 2023. Components of N-fixation system response to glyphosate are un-coupled in agroecosystems. Applied Soil Ecology
  52. *Keshta, A., S. Yarwood, A. Baldwin. 2023. Methane emissions are highly variable across wetland habitats in natural and restored tidal freshwater wetlands. Wetlands