Towson University

Biological  Sciences
Biological Sciences

 

                          

                                                                                                                                                                      Faculty

 

Susan Gresens, Ph.D.

Associate Professor

Department of Biological Sciences

Towson University

Towson, MD 21252 USA

 

Office:  Smith 223

Phone: 410-704-4368

Fax:      410-704-2405

 

email: sgresens@towson.edu

 

Education:

   

    Ph.D.  University of Chicago

    M.S.    University of Wisconsin        

    B.S.    S.U.N.Y. College at Oneonta           

 

Courses Taught:

   

    BIOL 208 - Biological Diversity

    BIOL 402 - General Ecology

    BIOL 406 - Limnology

    BIOL 609  - Community Analysis & Bioassessment

 

Research Interests:

Dr. Gresens specializes in freshwater ecology, with a focus on stream ecosystems.  Much of her research involves midges (Diptera: Chironomidae), a family of aquatic insects with high species diversity and an amazing range of ecological specialization.  Several research projects in her lab involve the use of floating chironomid pupal exuviae (cast pupal exoskeletons) to study the response of species diversity to urbanization in streams in the Baltimore area.  The ultimate goal of these projects is to develop statistical tools for bioassessement (tolerance values, biotic indices) that will be more sensitive to changes in ecological health of urban and suburban streams.  

 

Another research focus involves periphyton (i.e., attached algae), an important component of the base of stream food webs, and a habitat for many aquatic invertebrates.  Dr. Gresens maintains a long-standing interest in algal-grazer interactions, and studies mechanisms by which phosphorus limitation can influence the growth of both periphyton and invertebrate consumers in streams.  This has involved surveys of periphyton dynamics in local streams in relation to temporal variation in nutrients and disturbance.  In addition, her students conduct experimental studies of the effects of silt/clay sediments on nutrient limitation of periphyton in the laboratory.

 

 

Publications:

 

Gresens, S.E. and L.C. Ferrington, Jr. 2009. Chironomid species assemblages of streams draining areas of serpentine vs.

non-serpentine bedrock. Proceedings of the XVth International Symposium on Chironomidae. (In press).

 

Gresens, S.E.  and L.C. Ferrington, Jr. 2008. Taxonomic distinctness provides an alternative view of the diversity of chironomid

(Diptera) assemblages. Boletim do Museu Municipal do Funchal   Sup. No. 13: 101-108.

 

Sinclair, C.S. and S.E. Gresens. 2008. Discrimination of Cricotopus sp. (Diptera: Chironomidae) with mitochondrial gene

Cytochrome oxidase I sequence. Bulletin of Entomological Research 98:555-563.

 

Gresens, S.E., K.T. Belt, J.A. Tang, D.C. Gwinn and P.A. Banks. 2007. Temporal and spatial

responses of Chironomidae (Diptera) and other benthic invertebrates to urban stormwater

runoff.Hydrobiologia 575:173-190.

 

Gresens, S.E. and L.C. Ferrington, Jr. 2007. Chironomid species richness in streams draining

areas of serpentine vs. non-serpentine bedrock. Proceedings of the XVth International

Symposium on Chironomidae. (accepted).

 

Lawrence, J.M. and S.E. Gresens. 2004. Response of periphyton and grazers to nutrient

enrichment in rural vs. urban streams. Journal of Freshwater Ecology 19:375-385.

 

Gresens, S.E. 2001.  Thermal sensitivity of ingestion and digestion in larvae of a

eurythermal chironomid. Journal of the North American Benthological Society 20: 68-83.

 

Gresens, S.E.1997. Interactive effects of diet and thermal regime on growth of the midge             

Pseudochironomus richardsoni. Freshwater Biology 38:365-373.

 

Gresens, S.E. 1995. Grazer diversity, competition and the response of the periphyton

community. Oikos 73:336-346.

 

Current Graduate Students:

 

Cory Lavoie: “Use of chironomid pupal exuviae in bioassessment of Baltimore County streams”

 

 

Undergraduate Students:

Sasha Karosas TU REU student – University of Wisconsin- La Crosse: “Effects of silt-clay

            sediment in a phosphorus-limited algal-grazer food chain”

Kristin Fischer “Effects of flood disturbance on chironomid emergence”

Christine Luehman “Biotic impacts of sediment-bound metals in streams”

John Siwinski  “Comparing toxicity of streamwater using a Ceriodaphnia assay”

 

 

 

 

 

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