- Thermal tolerance and other water quality stressors
- Evaluating the thermal tolerance of unionid mussels and crayfish using aerobic scope: Using a variety of empirical and quantitative physiological measurements including respiration rate and enzymatic performance, we evaluate the physiological mechanisms behind unionid and crayfish thermal tolerance. Kaelyn Fogelman, Ph.D. candidate.
- A systematic review of the lethal, sublethal, and ecological effects of temperature on unionid mussels: To better understand the lethal and sublethal effects on unionids to better prepare for our changing climate, we are completing a comprehensive systematic review evaluating temperature as a water quality stressor on all unionid mussels including analyses by life stage and taxonomy. Kaelyn Fogelman, Ph.D. candidate.
- Lethal and sublethal effects of thermal and hypoxia stress on the endangered unionid Popenaias popeii: Evaluating thermal stress on P. popeii from the Black River, NM. Findings will be used to help develop environmental flow recommendations in collaboration with research at Texas A&M and Miami University, OH. Jessica Radich, M.S. student
- Linkages between thermal stress endpoints at different organizational levels.: Utilizing a multi-faceted approach, we are attempting to better describe the interconnected relationship between thermal stress, oxygen demand, and behavioral stress indicators to refine future management and research strategies of unionid mussels. As thermal stress has varying effects at the cellular and organismal levels, it is imperative to understand how the impacts are connected among levels of organization. To effectively delve into this issue, we examine the relationships between enzymatic performance curves, respiration patterns, behavioral responses and upper thermal tolerance limits. Patrick Jordan, M.S. student
- Sublethal effects of salinity on juveniles of the endangered Texas Hornshell (Popenaias popeii): P. popeii has had a major decline in suitable habitat and population connectivity due to anthropogenic impacts in their range. In particular, increased salinity in freshwater systems caused by prolonged droughts and over-drawing of water for human use has become an issue within their limited range. We aim to test effects of varying salinity levels on juvenile P. popeii energetics to examine potential impacts of increasing salinity. Evelyn Pieper, M.S. student.
- Exploring the linkages between physiology and thermal tolerance in crayfish: Understanding the physiological mechanisms behind thermal tolerance is of increasing importance in the face of ongoing climate change. In aquatic ectotherms, such as crayfish, metabolic rates initially increase with increasing temperature but eventually decline with further temperature increases-a change called metabolic depression. We use respirometry to compare relationships between temperature, metabolic depression, and mortality in crayfish to place them in thermal tolerance guilds. Kayla Boyd, Ph.D. student.
- Feeding ecology
- A comparison of unionid feeding ecology between lentic and lotic systems: To better understand the food resource utilization of unionid mussels in natural systems, we are using a combination of stable isotope and fatty acid analysis for multiple species and sites in Texas and Alabama to evaluate unionids primary dietary resources. Kaelyn Fogelman, Ph.D. candidate.
- Invasive species management
- Evaluation of carbon dioxide as a control technique for invasive Red Swamp Crayfish: We are conducting pond and raceway experiments to determine if CO2 can be used to “push” crayfish into a refuge area or towards the water surface for easier collection. Similarly we are examining the potential of water flow to “pull” crayfish towards a targeted section of a pond for more efficient trapping and removal. Gabrella Elliott, M.S. student.
- Evaluation of chemicals and physical blockers to control invasive crayfish in burrows: We are using a combination of laboratory burrowing chambers and induced burrows in pond bottoms to explore various control techniques for the burrowing phase of red swamp crayfish. Daniel Westrich, M.S. student.
- Use of Acoustic Tags to Track Movement of invasive Red Swamp Crayfish: Using a combination of raceway and pond studies, we are exploring the use of acoustic tags to track movement of red swamp crayfish exposed to control techniques. Gabrella Elliott, M.S. student.
- Bioenergetics of Asian Clam and native juvenile unionids: The Asian clam (Corbicula fluminea) has invaded many North American waterways. Studies have shown evidence of detrimental impacts on early life-stages of native freshwater mussels (Family: Unionidae). This project investigates potential competition between Asian clams and native unionids using bioenergetic modelling. Techniques involve measuring respiration rate with mini-respirometry, measuring filtration rate, and feces/psuedofeces production. Evelyn Pieper, M.S. student.
- Mussels and PFOS: Dirty Beds and Genes Expressed: Due to their filtration activities, mussels may transfer pollutants from the water column into their bodies and into the sediments. We conducted experiments to test whether sediment PFOS concentrations are higher when unionids are present and if fed unionids bioaccumulate more PFOS in the mussel tissues than fasted unionids. We also tested for changes in expression four genes associated with stress in male and gravid female unionids exposed to environmentally relevant PFOS concentration. Amanda Strozier, M.S. student.
- Measuring effects of contaminants on energetics and gene expression of the eastern oyster (Crassostrea virginica): Oysters are chronically exposed to a range of chemical contaminants in the natural environment, but effects of contaminant mixtures are not yet well understood. Using respirometry, we are testing for energetic costs of contaminant depuration when combined with other environmental stressors. We are also testing for altered gene expression following exposure to environmentally relevant combinations of contaminants. Kayla Boyd, Ph.D. student.
- Undergraduate Research:
- Our undergraduate researchers are invaluable and assist with daily feeding, water quality, water changes, setting up and completing field experiments, and generally – do the important work that keeps our lab running. We encourage our undergraduate students to hone their interests in our lab and to pursue their own independent research projects during their time with us.
Previous high school students have conducted experiments using our respirometry system (and won their division of the Alabama Science and Engineering Fair, proceeding to the state level) and evaluated crayfish hypoxia tolerance while assisting an international collaborative research effort.
We have a variety of aquatic systems to hold a wide array of aquatic fauna. Our bivalves are generally held in upwelling systems and depending on the project our crayfish are held in flow- through troughs or individual Aquatic Habitats (AHAB) tanks. Automatic feeder systems are used for our bivalves and each culturing system is temperature controlled. Additionally, we have separate systems for exposure to contaminants and ecotoxicology experiments. We also have two independent climate and photoperiod-controlled rooms for a variety of assays where temperature and photoperiod must be regulated. As our lab is located at the E. W. Shell Fisheries center, we also have access to experimental, earthen ponds for producing experimental animals and conducting field-based experiments. Other research labs at the station provide multiple opportunities for collaboration and professional advice from experts in diverse fields including aquaculture, ecology, nutrition, genetics, disease, and reproductive physiology.