Jill Welter

Associate Professor



Jill Welter is an ecosystem scientist with expertise in the ecology of streams. She maintains an active research program and engages undergraduate students in her research. Her work focuses on understanding how environmental change, including climate warming and eutrophication, influences species interactions and nutrient cycling in stream ecosystems. Since joining the St. Catherine faculty in 2005, Jill has turned her attention to the increasing role that nitrogen-fixing cyanobacteria may play in stream ecosystems as a result of rising temperatures, and the potential consequences for aquatic food webs and the coupled cycling of carbon, nitrogen, and phosphorus. Jill teaches courses in basic ecology, aquatic biology, ecosystem science, and global change. She also has a strong interest in the intersection between art and science and collaborates with faculty members in the arts and humanities, teaching interdisciplinary courses that examine topics from multiple disciplinary perspectives.

  • Pairing metabolic theory and ecological stoichiometry to understand ecosystem responses to environmental change.
  • The role of nitrogen fixation and microbial assemblages in driving food web dynamics and whole ecosystem metabolism in freshwater environments.
  • The influence of algal and cyanobacterial species assemblages on coupled C, N, and P cycling, food web dynamics, and nutrient retention.
  • How landscape structure and heterogeneity influence periphyton communities and the consequences for biogeochemical cycling in river networks.
  • Understanding how different physiological strategies (functional traits) influence species interactions and biogeochemical cycling in stream ecosystems and how they scale up to help us better predict whole ecosystem responses to climate warming and eutrophication.

Postdoctoral Research Associate, National Center for Earth-Surface Dynamics
University of California, Berkeley, 2005

Ph.D., Ecology/Ecosystem Science
Arizona State University, Tempe, Arizona, 2004

Bachelor of Science, Biology
University of Oregon, Eugene, Oregon, Phi Beta Kappa, 1991

St. Catherine University Endowed Professorship in the Sciences, 2015–2018

Collaborative Undergraduate Research Program Award. St. Catherine University, 2014

Summer Scholars Collaborative Undergraduate Research Program. St. Catherine University, 2014

Research and Scholarly Activities Award. St. Catherine University, 2012

Extramural Associates Research Development Award through the Office of Research and Sponsored Programs. St. Catherine University, 2011

Faculty Teaching-Advising Award Finalist. St. Catherine University, 2008, 2009

3M Large-Scale Student-Faculty Collaborative Research Award. St. Catherine University, 2007

Dr. Welter’s research has been funded by the National Science Foundation (Division of Environmental Biology & Division of Biological Infrastructure), a 3M Corporation Endowment, and St. Catherine University.

Welter, J.R. and S.G. Fisher. 2016. The influence of storm characteristics on hydrological connectivity in intermittent channel networks: implications for nitrogen transport and denitrification. Freshwater Biology DOI:10.1111/fwb.12734

Williamson, T.J., Benstead, J.P., Cross, W.F., Hood, J.M., Huryn, A.P., Johnson, P. & Welter, J.R. 2015. Coupling energy and elements in a warming world: how temperature shapes ecosystem structure and function. Global Change Biology DOI:10.1111/gcb.13205

Welter, J.R., Benstead, J.P., Cross, W.F., Hood, J.M., Huryn, A.P., Johnson, P. & Williamson, T.J. 2015. Does N2fixation amplify the temperature dependence of ecosystem metabolism? Ecology 96:603-610.

Finlay, J.C., J.M. Hood, M. Limm, M.E. Power, J.D. Schade, and J.R. Welter. 2011. Light-mediated thresholds in stream water nutrient composition in a river network. Ecology 92(1):140-150.

Schade, J.D., K. MacNeill, S.A. Thomas, F.C. McNeely, J.R. Welter, J. Hood, M. Goodrich, M.E. Power, and J.C. Finlay. 2010. The stoichiometry of nitrogen and phosphorus spiraling in heterotrophic and autotrophic streams. Freshwater Biology 56(3):424-436. doi:10.1111/j.1365-2427.2010.02509.x

Power, M., R. Lowe, P.C. Furey, J.R. Welter, M. Limm, J. Finlay, C. Bode, S. Chang, M. Goodrich and J. Sculley. 2009. Algal mats and insect emergence in rivers under Mediterranean climates: Towards photogrammetric surveillance. Freshwater Biology 54(10):2101-2115. doi:10.1111/j.1365-2427.2008.02163.x

Dent, C.L., N.B. Grimm, E. Marti, J.W. Edmonds, J.C. Henry, and J.R. Welter. 2007. Variability in surface-subsurface hydrologic interactions and implications for nutrient retention in an arid-land stream. Journal of Geophysical Research, 112, G04004. doi:10.1029/2007JG000467.

Fisher, S.G., J.B. Heffernan, R.A. Sponseller, and J.R. Welter. 2007. Fluvial ecomorphology: Feedbacks between form and function in fluvial landscape ecosystems. Geomorphology 89:84-96.

Tweeten, K.A., M.J. Myers., C.G. Norton, L.H. Gildensoph, M.M. Phillips, D.D. Wygal, J.J. Pellegrini, and J.R. Welter. 2006. Animating a biology curriculum with research. CUR Quarterly. XXVI:122-127.

Welter, J.R., S.G. Fisher, and N.B. Grimm. 2005. Nitrogen transport and retention in an arid land watershed: influence of storm characteristics on terrestrial-aquatic linkages. Biogeochemistry 76(5):421-440.

Fisher, S.G. and J.R. Welter. 2005. Flowpaths as integrators of heterogeneity in streams and landscapes. In: G.M. Lovett, C.G. Jones, M.G. Turner, and K.C. Weathers (editors). Ecosystem Function in Heterogeneous Landscapes. Springer-Verlag, New York.

Belnap, J., J.R. Welter, N.B. Grimm, N. Barger, and J.A. Ludwig. 2005. Linkages between microbial and hydrologic processes in arid and semi-arid watersheds. Ecology 86(2):298-307.

Sabo, J.L., R. Sponseller, M. Dixon, K. Gade, T. Harms, J. Heffernan, A. Jani, G. Katz, C. Soykan, J. Watts, and J. Welter. 2005. Riparian habitats increase regional species richness despite weak gradients in local richness along the upland-riparian transition. Ecology 86(1):56-62.

Welter, J.R. (2016) Nitrogen fixation in river ecosystems: Controls and consequences. Imperial College, London, England.

Welter, J.R. (2016) Start seeing nitrogen fixation: How nitrogen fixation influences food webs and biogeochemical cycling in freshwater ecosystems. The Institute of Freshwater Fisheries, Reykjavik, Iceland.

Welter, J.R. (2015) Nitrogen fixation in a warming world. Making Waves Podcast: Episode 14. The Society for Freshwater Science.

Welter, J.R. (2015) Potential consequences of nitrogen fixation in a warming world: Predicting the effects of climate change on stream ecosystems using a natural geothermal laboratory. Woods Hole Marine Biological Laboratory, Woods Hole, Massachusetts.

Welter, J.R. (2015) Understanding the effect of warming on productivity, species composition, and nutrient cycling in river ecosystems. IceBio 2015, University of Iceland, Reykjavik.

Welter, J., Williamson, T., Cross, W., Hood, J., Benstead, J., Huryn, A., Ahles, A. and Goldschmidt, J. (2014) Nitrogen fixation amplifies the temperature-dependence of primary production in streams. Joint Aquatic Sciences Meeting, Portland, OR.

Welter, J., Scott, J., Marcarelli, A. and Fulweiler, R. (2014) Special Session Panel Discussion: We’ve got a nitrogen fixation: Exploring integrating, and understanding nitrogen fixation along the freshwater to marine continuum. Joint Aquatic Sciences Meeting, Portland, OR.

Welter, J. (2014) Iceland: Testing the waters of climate change. The Clare, Chicago, IL - sponsored by St. Catherine University Alumnae Association

Welter, J. (2014) The potential ecological consequences of nitrogen fixation in freshwater ecosystems. The Institute of Freshwater Fisheries, Reykjavik, Iceland.

Welter, J. & Tweeten, K. (2013) Earth, life and diversity: The process of evolution. Sisters of St. Joseph Wisdom Ways - Hedgerow Initiative: Earth, Life, and Diversity.

Welter, J., Sander, D., Lawrence, B., Furey, P. & Hood, J. (2013) Effect of temperature on N2-fixation rates and N2-fixer species assemblages in streams in the Hengill region of Iceland. Society for Freshwater Science, Jacksonville, FL.

Welter, J. (2012) State of climate science. St. Catherine University School of Business and Leadership: Sustainability – People, Planet, Profits.

Welter, J.R., P.C. Furey, M.E. Power, A.R. Bratt, B.L. Weigel, J.A. Cormier. (2012) Interactive effect of floods and grazing on abundance, activity, and species composition of nitrogen fixers in a river network. Society for Freshwater Science Annual Meeting, Lexington, KY.

Welter, J.R., P.C. Furey, J.A. Cormier, A.J. Rosendahl, B.L. Weigel, G.M. Wilkinson. (2011) Abiotic and biotic constraints on nitrogen fixation and producer species assemblages in an N-limited river ecosystem. Ecological Society of America Annual Meeting, Austin, TX.

Welter, J.R. and K.A. Boeff. (2011) Integrated research and teaching: Calculating our greenhouse gas footprint. St. Catherine University Teaching Learning Network Symposium.

Welter, J.R., A.R. Bratt, H.M. Kaup, N.A. Turner, P.C. Furey, J.C. Finlay, and M.E. Power. (2010) Spatial and temporal patterns in nitrogen fixation in a river network. Joint Meeting of the American Society of Limnology and Oceanography & North American Benthological Society, Santa Fe, NM.

Welter, J.R. (2010) Biogeochemical cycling in stream networks. Associated Colleges of the Twin Cities (ACTC) Ecology and Evolution Faculty Symposium.

C.E. Gray and J.R. Welter. (2010) St. Catherine University - Our greenhouse gas footprint: Linking our emission to our mission. St. Catherine University Teaching Learning Network Symposium.

Welter, J.R., H.M. Kaup, A.R. Bratt, and M.K. Moenkedick. (2009) Nitrogen fixation and coupled N and P cycling linked with stream network position. Ecological Society of America Annual Meeting, Albuquerque, NM.

Welter, J.R. (2009) Coupling consumer-resource interactions and nutrient spiraling in a river network. National Center for Earth Surface Dynamics Seminar: St. Anthony Falls Laboratory, University of Minnesota.