Senior Scientist

Tel: 508-289-7487 | Fax: 508-457-154

E-mail: ldeegan@mbl.edu

Ph.D. Louisiana State University, 1985
M.S. University of New Hampshire, 1979
B.S. Northeastern University, 1976

Full CV

Research Statement

I am interested in the relationships between ecosystem dynamics and animal populations. As the trophic-dynamic model of whole ecosystems gained favor in the 1960's and 70's, the importance of animals in structuring ecosystems was neglected. New interest in the role of animals in ecosystems has been stimulated by work in community ecology that demonstrated that keystone species strongly influence community composition and work as "top-down" controls on productivity. We now know that grazing, predation and physical disturbance by animals can influence a host of processes at the ecosystem level. My research combines the ecosystem perspective of energy and nutrient flows with traditional population and community dynamics.

I find aquatic ecosystems to be particularly interesting because of their importance in connecting landscape elements through the flow of water and animals. I have examined problems ranging from the importance of fish in exporting nutrients and carbon from estuaries, to the effect of habitat degradation on fish community structure in coastal embayments, to the response of upper trophic levels to increased nutrients in arctic streams. I use a combination of approaches to address these questions ranging from surveys of fish abundance and species composition to traditional gut content analyses as well as state of the art techniques such as measuring of the natural abundance and flows of ¹⁵N tracers in food webs.

Through collaboration with other scientists at the center, I am also able to assess how animals influence processes like nutrient regeneration. One of my current interests is the ways that animals, through feeding, constructing burrows, or migration can regulate or modify biogeochemical cycles.

Recent Publications

Deegan, L.A. D.S. Johnson, R.S. Warren, B.J. Peterson, J.W. Fleeger, S. Fagherazzi, W.M. Wollheim. 2012. Coastal eutrophication as a driver of salt marsh loss.  Nature 490:388-392.

Fagherazzi S., FitzGerald D.M., Fulweiler R.W., Hughes Z., Wiberg P.L., McGlathery K.J., Morris J.T., Tolhurst T.J., Deegan L.A., Johnson D.S. In press. Ecogeomorphology of Salt Marshes, Treatise on Geomorphology, Volume 12 Ecogeomorphology. Editors: Butler D., Hupp C., Executive Editor: Shroder J.  Elsevier.

Galván, K., J.W. Fleeger, B.J. Peterson, D. Drake, L.A. Deegan, and D.S. JohnsonG. 2011.  Natural abundance stable isotopes and dual isotope tracer additions help to resolve resources supporting a saltmarsh food web.  Journal of Experimental Marine Biology and Ecology 410: 1-11.

Bowen, J.L., B. B Ward, H. G Morrison, J. E. Hobbie, I. Valiela, L. A. Deegan and M. L Sogin. 2011. Microbial community composition in sediments resists perturbation by nutrient enrichment. International Society for Microbial Ecology (ISME): 1-9.

Mather, M. E, J. T. Finn, S. M. Pautzke, D. Fox, T. Savoy, H. M. Brundage III, L. A. Deegan, and R. M. Muth. 2011. Destinations, routes, and timing of adult striped bass on their southward fall migration: implications for coastal movements. Journal of Fish Biology 77: 2326–2337.

Deegan, L. A., Neill, C., C. L. Haupert, M. V. R. Ballester, A. V. Krusche, R. L. Victoria, S. M. Thomas and E. de Moor. 2011. Amazon deforestation alters small stream structure, nitrogen biogeochemistry and connectivity to larger rivers. Biogeochemistry 105: 53-74.

Bowen, J.L., B.C. Crump, L.A. Deegan and J.E. Hobbie. 2009. Increased supply of ambient nitrogen has minimal effect on salt marsh bacterial production. Limnology and Oceanography 54:713-722.

Bowen, J.L., B.C. Crump, L.A. Deegan and J.E. Hobbie. 2009. Salt marsh sediment bacteria: their distribution and response to external nutrient inputs. The ISME Journal 3:924-934, doi:10.1038/ismej.2009.44.

Buchsbaum, R.N., L.A. Deegan, J. Horowitz, R.H. Garritt, J.P. Ludlam and D. H. Shull. 2009. Effects of regular salt marsh haying on marsh plants, algae, invertebrates and birds at Plum Island Sound, Massachusetts. Wetlands Ecology and Management 17:469-487, doi: 10.1007/s11273-008-9125-3.

Drake, D.C., B.J. Peterson, K.A. Galván, L.A. Deegan, C. Hopkinson, J.M. Johnson, K. Koop-Jakobsen, L.E. Lemay and C. Picard. 2009. Salt marsh ecosystem biogeochemical responses to nutrient enrichment: a paired ¹⁵N tracer study. Ecology 90(9):2535-2546.

Deegan, L.A., J.L. Bowen, D. Drake, J.W. Fleeger, C.T. Friedrichs, K.A. Galván, J.E. Hobbie, C. Hopkinson, J.M. Johnson, D.S. Johnson, L.E. Lemay, E. Miller, B. J. Peterson, C. Picard, S. Sheldon, J. Vallino, R.S. Warren. 2007. Susceptibility of salt marshes to nutrient enrichment and predator removal. Special Issue "Nutrient Enrichment Of Estuarine And Coastal Marine Environments" (Mike Kennish, Special Issue Editor). Ecological Applications 17(5):S42-S63.

Benstead, J.P., A.C. Green, L.A. Deegan, B.J. Peterson, K. Slavik, W.B. Bowden and A.E. Hershey. 2007. Recovery of three Arctic stream reaches from experimental nutrient enrichment. Journal of Freshwater Biology 52(6): 1077-1089.

Neill, C., L.A. Deegan, S.M. Thomas, C.L. Haupert, A. Krusche, V. Ballester and R. Victoria. 2006. Deforestation alters the hydraulic and biochemical characteristics of small lowland Amazonian streams. Hydrologic Processes 20:2563-2580.