Our wet labs are equipped for short term housing and processing of animals, dissections, as well as a variety of analytical procedures. The labs contain two hoods, a Percival environmental chamber (with photoperiod, temperature, and humidity control), four soxhlet units for nonpolar lipid extraction, an Iatroscan for polar lipid separation, two dissecting scopes, multiple benchtop analytical balances, two portable ultrasound units, a Morphosys visual imaging system, as well as gel electrophoresis and blotting systems. Combined with our freezer/oven building, we also have four standard freezers, a refrigerator/freezer, two ultracold freezers, a lyopholizer, drying ovens, a dry glove box, and a muffle furnace.

The Wildlife Ecotoxicology and Physiological Ecology Program also has ample office space for technicians, graduate students, and visiting scientists. We have two offices dedicated to senior researchers in the program and a large shared office for graduate students and technicians. All offices are well equipped with computers, printers, etc. Select these links to learn more about educational or employment opportunities in Dr. Hopkins’ laboratory.

Analytical Laboratory
Our analytical laboratory is fully equipped with three state-of-the-science respirometry systems (Columbus instruments, Columbus OH). The system that is utilized for most studies is our Micro-Oxymax, a computer-controlled, closed system respirometer that measures both oxygen consumption and carbon dioxide production simultaneously. It is interfaced with a large Revco environmental chamber that allows control of daily cycles in photoperiod and temperature. The Micro-Oxymax is a powerful analytical device best used on smaller ectothermic organisms. Because the system is computer-controlled and can simultaneously monitor up to 18 animals (plus one standard and a blank), researchers can address questions with this system that are quite difficult with traditional manual systems.

The Micro-System is convertible to our open-flow respirometry system by using alternative software options and our external fresh air pump controlled by an equal flow meter. This system monitors both oxygen consumption and carbon dioxide production simultaneously in up to 8 animals at a time. The system is best suited for organisms that respire at high rates (compared to animals appropriate for the Micro system), including larger ectothermic vertebrates (e.g., large rattlesnakes) and endotherms. Our third system is the ER-10, a computer controlled open-flow respirometry system that is fully portable. The system is interfaced with a laptop computer, making it suitable for both field and laboratory work abroad. Although not as sensitive as the Micro-Oxymax, use of small respiratory chambers allows measurement of oxygen consumption and carbon dioxide production in fairly small ectothermic organisms (e.g., 10 g lizards at 25º C).

Performance Equipment
One of the focal points of our recent toxicological research on lizards and snakes has been locomotor performance. We recently acquired two state-of-the-science instruments (Columbus Instruments) for quantifying performance in terrestrial vertebrates. The first of these instruments is a 2.5m long stainless steel sprint performance runway designed for quantification of maximum sprint velocity in small vertebrates. Beyond the start-box at one end of the runway, the 2.3 m running portion of the runway is lined with a rubber substrate and equally spaced 23 photocell gates (paired infrared emitter and detector on opposite sides of the runway). The photocell gates are interfaced with a Dell Pentium III laptop computer that records gate events (i.e., breakage of photocell beams) with 10ms resolution. The second instrument is a modular treadmill used for determining endurance. The treadmill is interfaced to a manual control unit that allows the running belt to be controlled from 0 to 99.9 m/m in 0.1 m/m steps. The track is enclosed (to prevent animals from jumping off) and can be inclined from 0 to 25º in 5º steps. The track has multiple removable endcaps, one that allows it to be interfaced with our ER-10 respirometer, and a rear endcap that includes a shock grid that provides motivation to remain on the running surface. The optional shock grid is controlled by an external power source that controls both the intensity and pulse rate of the stimulus.

Swimming performance has also been the focus of several recent investigations in our laboratory. We are equipped to measure both maximum swim speed and endurance in small aquatic organisms (e.g., tadpoles, fish, snakes). Maximum swim speed is determined by racing animals along a 3m plastic swim track with a background marked at 1.0 cm increments. Dorsal images of the swim trials are recorded using a digital video camera. Images are analyzed using a frame-by-frame advance with accuracy to 0.01 - 0.03 sec (digital and VHS, respectively). Endurance measures (e.g., critical swimming speeds) are determined using a laminar-flow swim tunnel. Water is continuously propelled through the swim tunnel using a 0.75 HP DC motor with a 6 cm propeller connected to a Dayton 0.75 HP DC speed control device calibrated against water flow velocity using a Marsh-McBirney 201D flowmeter. Laminar flow in the swim tunnel is achieved using a plexiglass collimeter preceding the propeller and two soda straw arrays upstream from the swim area.

Tank Farms
As a useful intermediate to field and laboratory research, simulated aquatic communities (outdoor mesocosms) have frequently been used by SREL researchers to address community-level problems. The Wildlife Ecotoxicology and Physiological Ecology Program has followed this strong tradition by using outdoor mesocosms to understand the effects of environmental contaminants on aquatic systems. At the Aquatic Ecology Laboratory (a satellite facility of SREL under the custodianship of Dr. Hopkins), we have two large areas set aside for mesocosm research and are well equipped for working at various spatial scales. Using mesocosms ranging in size from large cattle tanks to small (~ 100L) plastic bins, we have gained considerable insight into the direct and indirect effects of environmental contaminants on aquatic invertebrates and their predators. For more information, please click here.