Ecotoxicology and Physiological Ecology at CBL:  The research group of Christopher Rowe

Overview:  <>

    Our research deals with the sublethal effects of water- and sediment-borne contaminants in estuarine and freshwater ecosystems in the Chesapeake Bay watershed and other regions of the United States.  We focus on effects of contaminants and other abiotic factors on individual fitness and population dynamics that result from cumulative, physiological changes experienced by individuals.  Our research uses animal models including macroinvertebrates, fish, amphibians, and reptiles to examine contaminant effects across taxa displaying disparate life history strategies.  Much of our work is based upon experimental analyses of bioenergetic, endocrinological, and reproductive changes resulting from exposure to low concentrations of contaminants over the lifetime of individuals.  By examining effects of abiotic stressors at environmentally realistic concentrations and throughout chronic exposure periods, we hope to advance the understanding of the often subtle routes by which individual-based responses can bring about ecological change. 

Current Research Projects:

“Studies Using Aquatic Turtles (the Diamondback Terrapin and Snapping Turtle) to Assess Long-term Effects of Oiling of Nests During Early Embryonic Development.”  <>NOAA, Coastal Response Research Center.  Collaborator:  Dr. Carys Mitchelmore. 
     This project examines the chronic effects on traits of turtles that result from exposure to fresh crude oil and post dispersant treated-oil during early embryonic development as would occur via oiling of nests.  Exposures are provided to artificial nests containing eggs during early embryonic development, modeling a scenario in which oiling of nests occurs shortly after nesting.  The project has significance to the brackish, estuarine, and coastal habitats of the Atlantic and Gulf coasts of the U.S. due to the cosmopolitan distribution of the model species (the diamondback terrapin, Malaclemys terrapin, and the snapping turtle, Chelydra serpentina) throughout these regions.  As well, the results will be applied to assessment of risks of oil spills to beach-nesting sea turtles, which we are not directly studying due to their protected status.  Our studies are addressing numerous endpoints over a full year post-hatching including development, cellular and whole animal physiology, and behavior. 
      Specific Topics of Study:  1) Thyroid hormone dynamics;  2)  Morphology and behavior; 3) Metabolic efficiency, growth, and energy storage; 4) Cellular and subcellular damage;  5)  Egg shell permeability to oil-derived PAHs; 6)  Physicochemical aspects of water accomodated fractions of oil in nest substrates. 

“Reproductive Ramifications of PCB Exposure in Snapping Turtles of the Upper Hudson River.”  Hudson River Foundation.  Collaborators:  Drs. Carys Mitchelmore and Joel Baker. 
        This project is examines relationships between PCB accumulation by snapping turtles (Chelydra serpentina) in the Hudson River and biological responses related to performance and reproductive fitness.  The primary research question that we are addressing is “Do natural systems contaminated by high concentrations of PCBs present biological risks to wild populations via disruptions of normal reproductive processes?” We are employing a multifaceted approach that includes molecular, cellular, physiological, developmental, and autecological assessments of snapping turtles inhabiting PCB contaminated and relatively uncontaminated portions of the Hudson River.  Our overall goal is to determine whether there are potentially fitness-related effects of PCBs on endemic reptile populations in the Hudson River. 
         Specific Topics of Study:  1)  Bioaccumulation and maternal transfer to offspring of PCBs in a natural system; 2)  Sexual morphology and circulating hormone concentrations in adult turtles inhabiting the system; 3)  Thyroid dynamics in hatchlings receiving maternally-derived PCBs; 4)  Morphology and behavior of hatchlings;  5)  Long-term bioenergetic and growth responses of hatchlings; 5) Cellular and subcellular effects of PCBs in hatchlings. 


Recently Completed Research Projects (past 2 years): 

"Modeling the Individual and Interactive Risks to an Amphibian Population Resulting from Breeding Site Contamination and Terrestrial Habitat Loss."  USEPA STAR Program.  Collaborator:  Dr. William Hopkins.

“Assessing Population Status of the Diamondback Terrapin in Chesapeake Bay.”  Maryland Department of Natural Resources.  Collaborator:  Dr. Thomas Miller. 

“Quantifying Ecological Risks of Contaminated Sediments on Living Resources in Supporting Decisions on Habitat Restoration Strategies in the Chesapeake Bay.”   NOAA Sea Grant.  Numerous collaborators at several institutions. 

Publications:

See CBL Faculty Web Page.

Current Laboratory Personnel:
  
     Graduate Students:
        Karen Eisenreich (Ph.D.):  Embryonic and juvenile traits of snapping turtles resulting from maternal transfer of PCBs. 
        Shannon Kelly (M.S.):  Traits of adult snapping turtles displaying high concentrations of PCBs accumulated in the upper Hudson River<>. 
        Danika Kuzmick (M.S.):  Influences of chronic exposure to food- and sediment-borne trace elements on population dynamics of estuarine shrimp.
       Teresa Manyin (Ph.D.):  Bioenergetic responses and population dynamics of esturine shrimp to low concentraions of, water-borne cadmium and copper.

    Technical Personnel:
       Ashley Sides, laboratory technician.
       Katie Williams, field and laboratory technician.

       Christine Komar, Administrative assistant.

Recent and Ongoing Graduate Teaching Activities:

       "Introduction to Bioenergetics and Population Dynamics."  Co-taught with Dr. Thomas Miller
        "Seminar in Ecotoxicology."  Co-taught with Dr. Carys Mitchelmore
       "Seminar in Evolutionary Processes and Environmental Stress."