MED has capabilities to perform a wide range of inorganic analyses. Varian atomic absorption spectrophotometers, Flame (Spectra 220 Fast Sequential) and Furnace (GTA 880Z), are used to determine inorganic elements in liquid and solid matrices. An Agilent 7500 Series ICP mass spectrometer is currently being used for iodine determinations. Nutrients (orthophosphate, ammonium, nitrate+nitrite, total nitrogen and phosphorus, and silica) in biological and physical samples are quantitated using Lachat Quikchem 8000 flow injection analyzers. Ionic compounds (fluoride, chloride, bromide, and sulfate) are analyzed using a Dionex DX-600 ion chromatograph. Aqueous carbon constituents are quantified using Tekmar-Dohrman carbon analyzers (Phoenix 8000 and Apollo 9000). Solid samples are analyzed for carbon and nitrogen using a Thermo Flash EA 1112 analyzer. A Horiba LA-900 laser scattering analyzer is used for particle size distributions in sediments and slurries. Stable isotopes of C, N, O, and H are found using a Thermo Delta Plus XP CF stable isotope ratioing mass spectrometer, Conflo III, with Costec EA and Thermo TC/EA front peripherals.
The Division has some of the latest equipment available in the Biochemistry, Cellular, and Molecular Biology areas. This includes two Applied Biosystems 7500 QPCR thermal cyclers for the quantitative measurement of gene expression, as well as several other standard format thermal cyclers for DNA amplification. Additionally, through our connections with the EPA’s toxicogenomics core facility, we are able to conduct and analyze data from genomic microarray experiments. We have an Agilent 2100 Bioanalyzer for microfluidics-based analysis of DNA, RNA, proteins, and cells. We have a Cary 300 UV/Visible spectrophotometer, and two Nanodrop spectrophotometers for small volume samples. We have a Bio-Rad Fluoro-S Multi-imager for quantitative analysis of chemiluminescent, fluorescent, and UV/Visible images. We also have a BioTek Synergy 4 multi-format plate reader capable of luminescent, fluorescent, UV/Visible analysis. We have equipment for 1 and 2-dimensional gel electrophoresis of proteins and numerous options for gel electrophoresis of nucleic acids. We have several scintillation counters and a gamma counter for measurement of radioactivity. Facilities are available on site for cell and tissue culture. We have numerous microscopy options available, including a multi-photon laser-scanning microscopy. Additionally, numerous high-end options for chemical analysis support are available within the lab, including several GC, LC, MS instruments.
The wet lab is an integral part of the successful operation of MED toxicological research. A complete renovation of the facility was finished in 2007. This state-of-the-art facility complements the laboratory’s cutting edge research. Nearly all of the organisms used at MED originate from the culture activities in the wet lab. MED currently cultures a diverse array of aquatic organisms including several species of small fish; i.e., fathead minnows, medaka, zebrafish, two species of Xenopus, rainbow trout, and various classes of invertebrates, such as Lumbriculus, Hyallela, and Daphnia. It is operated by a contract staff of five biologists, who have expertise in developing husbandry protocols for standard model and field collected organisms. MED’s location on Lake Superior makes this facility possible; Lake Superior is the water source for the cultures. Annually, 20,000,000 gallons of water are filtered, sterilized, de-gassed, warmed or chilled, and delivered to culture tanks. The wastewater from the tanks is treated onsite with filtration, and UV/ozone sterilization before being returned to Lake Superior. The design of the facility allows specific rooms to be set up for each culture. This enables research teams to customize several critical husbandry parameters: photoperiod, water and room temperature, water pretreatment, and isolation of strains or species.
MED scientists use a combination of state-of-the-art Geographic Information Systems (GIS) software, hardware, data, and innovative techniques in research efforts to characterize the relative sensitivity of freshwater systems to cumulative stress, devise diagnostic landscape and habitat indicators, and derive relationships of landscape structure and corresponding land use activities to the sustainability of aquatic systems.
MED leverages EPA’s Enterprise License Agreement (ELA) with Environmental Systems Research Institute, Inc. (ESRI) to provide researchers access to ESRI GIS support services and software for desktops, servers, and mobile devices. Other GIS software packages available at MED include ERDAS IMAGINE Professional and Google Earth Pro.
MED maintains several pieces of hardware including servers, workstations, and plotters that are vital to GIS applications and research.
GIS data are obtained primarily from other federal, state, and regional agencies; universities; non-profit organizations; or commercial data sources. Data are also obtained through direct measurement, remote sensing (satellites and aerial photography), and model simulations of real-world conditions. Multiple temporal and spatial scales are relevant to ecological processes, therefore, data vary in scale from single sites (well locations and point source discharge) to regional extents (mature forest composition, wetland distribution); from historic knowledge (geological formations, original vegetation) to current indicators (aquatic population estimates); to predictions of the future (global climate change scenarios).
MED has an assortment of aquatic instrumentation for conducting research and development. Several standard CTDs (conductivity, temperature, depth sensors; Seabird SBE 19+, 25, and 911 systems) are available with an assortment of peripheral sensors that include fluorometers, transmissometers, pH probes, oxygen probes, and PAR sensors. We have various acoustic systems: a Questor Tangent Corporation bottom classification system, a Teledyne Mariner Workhorse ADCP (acoustic Doppler current profiler), and an HTI fish acoustic system. We have a laser optical plankton counter (LOPC, Brooke Ocean Technology) for in situ zooplankton monitoring. We have two tow systems with conducting cables that can be used for profiling surveys across large spatial scales. One system is a VFIN (YSI) fixed wing tow platform for surveying depths to greater than 100m from larger vessels, and the other is an adjustable wing Minibat (Guildline Technologies) for depths to 50m conducted from a smaller boat (26’).
MED has a Zeiss (formerly Bio-Rad) Radiance 2000 confocal and multiphoton excitation microscope. Multiphoton excitation is achieved by a tunable Ti:Saph laser, a SpectraPhysics Tsunami, which is pumped by a 10W Millennia X laser. The Ti:Saph laser can be tuned from ~710 nm to ~1000 nm allowing for excitation of a wide range of fluorophores. Multiphoton excitation allows for deeper imaging within samples and longer term imaging of living samples than typical confocal microscopy. This is because the wavelengths used in multiphoton microscopy are not attenuated, do not photobleach, and do not produce phototoxicity to the same extent as the lower wavelengths used in confocal microscopy. In addition to standard photomultipliers (PMTs), the microscope is equipped with external or direct PMT detectors that allow for both increased sensitivity and customizability. By using standard fluorescent filter blocks, these detectors allow for easy and relatively inexpensive customized detection strategies. The Radiance 2000 is also equipped with 488, 568, and 637 nm laser lines for confocal microscopy using the same software and emission filters as in multiphoton excitation.
The Division also has several stereo-dissecting microscopes, some with epi-fluorescent capabilities, and both a Zeiss Axiovert 35 and a Nikon Eclipse TE300 inverted microscope with epi-fluorescent capabilities. The stereo-dissecting and inverted microscopes are coupled with digital cameras for research-grade image collection. In particular, the Nikon inverted microscope is equipped with many objective options including several Super Fluors, a wide range of Plan Apos, and several immersion lenses (water, oil, and glycerin).
The exposure laboratory room 280 is a state-of-the-art facility for conducting static and flow-through aquatic exposures. It was originally designed to accommodate high impact chemicals such as dioxin. Exposure chambers with artificial spawning substrates were constructed and used to conduct lifecycle studies with Brook Trout as part of a national reassessment of the chemicals’ impact on an aquatic species. Currently the laboratory is home to endocrine disruptor research projects with fathead minnows, Medaka, and Xenopus. Test systems are designed and maintained to meet the needs of working with each species, as well as providing a contaminant free work environment for researchers. One of the project’s roles is to develop screening methods to identify chemicals with the potential to affect the hormone system in these aquatic species. Parts of the project’s design are the measurement of gene, protein, and metabolite changes in the organisms as well as mortality, reproduction, and behavioral changes. Exposures are normally days, weeks, or even years in length and support the EPA’s commitment to protecting the environment.
The Mid-Continent Ecology Division maintains a fleet of research vessels for inland, coastal, and Great Lakes research.
The flagship vessel is the R/V Lake Explorer II, a 90’ long, 220 ton displacement vessel that is used for Great Lakes research, specializing in developing a comprehensive environmental assessment of coastal conditions in the Great Lakes. For detailed information on the R/V Lake Explorer II, click here.
MED also has two coastal vessels, the R/V Tullibee and the R/V Prairie Sounder.
- The R/V Tullibee (26’ SeaArk Surveyor hull, Mercruiser7 engine) is used for deploying sophisticated sensor packages to assess water quality and for benthic surveys. The vessel has a hydraulic A-frame and winch for equipment deployment. An armored digital cable can support real-time communications from onboard computers to underwater sensors. A rear-facing science station is used for data collection and tow body operation. A forward-facing science station is used to operate an acoustic sea bottom profiler (Quester Tangent Corporation), integrated with real-time differential GPS.
- The R/V Prairie Sounder (25’ Roe MarineCraft, dual 135 hp Honda 4-stroke outboards) is used for fisheries research, specializing in deployment of a Tucker trawl for larval fish sampling. The working deck has a hydraulic winch and extended davit for gear deployment. An armored digital cable can support real-time communications from onboard computers to underwater sensors. Data can be integrated with real-time differential GPS.
The small vessel fleet includes two canoes (15’, 16’), four flat-bottomed john boats (12’-16’), a v-hull style boat (18’), and two flat-bottom jet boats (16’, 18’). These are used for research in lakes, rivers, and wetlands. Additionally, a flat-bottom boom-shock electro-fishing vessel (18’; Smith-Root 5.0 GPP electro-fisher) is used for sampling fish.