Travis S Schmidt, Ph.D.
Travis Schmidt, Ph.D., is a Research Ecologist for the Colorado Water Science Center and is co-located with the Aquatic Science Branch of the Fort Collins Science Center. He has degrees from The Pennsylvania State University, Virginia Tech, and Colorado State University. He joined the USGS as a Mendenhall Fellow in 2007 and has devoted his career to understanding how stressors shape aquatic and riparian ecosystems. His work focuses on using a combination of field observations, models, and laboratory experimentation to discover how ecosystems work.
- Ph.D. Ecotoxicology, Fish, Wildlife, and Conservation Biology, Colorado State University, 2007
- M.S. Aquatic Toxicology, Biology Department, Virginia Tech, 2001
- B.S. Ecology, Biology Department, The Pennsylvania State University, 1998
- 2009 to present, Research Ecologist, Colorado Water Science Center, Fort Collins, CO
- 2007-2009, Mendenhall Fellow, Central Mineral and Environmental Science Center, Denver, CO
- 2003-2007, USDA Fellow, Colorado State University, Fort Collins, CO 2001-2003, Ecotoxicologist, ELM Consulting, Chicago, IL
- 1999-2001, Research Assistant, Virginia Tech, Blacksburg, VA
- 1998-1999, Research Assistant, Aquatic Ecology Lab, The Ohio State University, Columbus, OH
- 1998-1999, Department of Biology, Notre Dame University, South Bend, IN
- 2015 to present, Faculty Affiliate, Fish, Wildlife, and Conservation Biology, Colorado State University, Fort Collins, CO
- 2015 to present, Faculty Affiliate, Graduate Degree Program in Ecology, Colorado State University, Fort Collins, CO
- 2016 to present, Faculty Affiliate, Zoology, Colorado State University, Fort Collins, CO
Science and Products
Water quality and aquatic life standards that are set by Federal and state regulatory agencies are used to evaluate the quality of our nation’s water and the health of aquatic ecosystems. These standards currently are based on hardness of the water and are determined for single metals, not for mixtures of metals that are typically found in natural systems. Metal mixtures can potentially be...
Cold-water fishes like trout, salmon, and charr are especially vulnerable to shifting conditions related to climate change; for example, warmer temperatures and more variable hydroclimate. Native cutthroat trout of the southern Rocky Mountains now only occupy a tiny fraction of their historic habitats because of stressors such as non-native fishes, habitat fragmentation, and detrimental land...
Most aquatic insects live in fresh water as larvae and move to land as flying adults to complete their life cycle. Although often ignored, the emergence of adults can transfer the effects of contamination from aquatic to terrestrial ecosystems as the adults are eaten by predators such as spiders, birds, and bats.
Disentangling the effects of low pH and metal mixture toxicity on macroinvertebrate diversity
One of the primary goals of biological assessment of streams is to identify which of a suite of chemical stressors is limiting their ecological potential. Elevated metal concentrations in streams are often associated with low pH, yet the effects of these two potentially limiting factors of freshwater biodiversity are rarely considered to interact...Fornaroli, Riccardo; Ippolito, Alessio; Tolkkinen, Mari J.; Mykrä, Heikki; Muotka, Timo; Balistrieri, Laurie S.; Schmidt, Travis S.
Complex mixtures of dissolved pesticides show potential aquatic toxicity in a synoptic study of Midwestern U.S. streams
Aquatic organisms in streams are exposed to pesticide mixtures that vary in composition over time in response to changes in flow conditions, pesticide inputs to the stream, and pesticide fate and degradation within the stream. To characterize mixtures of dissolved-phase pesticides and degradates in Midwestern streams, a synoptic study was...Nowell, Lisa H.; Moran, Patrick W.; Schmidt, Travis S.; Norman, Julia E.; Nakagaki, Naomi; Shoda, Megan E.; Mahler, Barbara J.; Van Metre, Peter C.; Stone, Wesley W.; Sandstrom, Mark W.; Hladik, Michelle L.
Thermal regimes of Rocky Mountain lakes warm with climate change
Anthropogenic climate change is causing a wide range of stresses in aquatic ecosystems, primarily through warming thermal conditions. Lakes, in response to these changes, are experiencing increases in both summer temperatures and ice-free days. We used continuous records of lake surface temperature and air temperature to create statistical models...Roberts, James J.; Fausch, Kurt D.; Schmidt, Travis S.; Walters, David M.
Zinc concentrations and isotopic signatures of an aquatic insect (mayfly, Baetis tricaudatus)
Insect metamorphosis often results in substantial chemical changes that can fractionate isotopes and alter contaminant concentrations. We exposed larval mayflies (Baetis tricaudatus) to an aqueous zinc gradient (3-340 µg Zn/l) and measured the change in zinc tissue concentrations at different stages of metamorphosis. We also measured changes in...Wesner, Jeff S; Walters, David; Schmidt, Travis S.; Kraus, Johanna M.; Stricker, Craig A.; Clements, William H.
Metamorphosis affects metal concentrations and isotopic signatures in a mayfly (Baetis tricaudatus): Implications for the aquatic-terrestrial transfer of metals
Insect metamorphosis often results in substantial chemical changes that can alter contaminant concentrations and fractionate isotopes. We exposed larval mayflies (Baetis tricaudatus) and their food (periphyton) to an aqueous zinc gradient (3-340 µg Zn/l) and measured zinc concentrations at different stages of metamorphosis: larval, subimago, and...Wesner, Jeff S.; Walters, David; Schmidt, Travis S.; Kraus, Johanna M.; Stricker, Craig A.; Clements, William H.; Wolf, Ruth E.
Bifenthrin causes trophic cascades and alters insect emergence in mesocosms: implication for small streams
Direct and indirect ecological effects of the widely used insecticide bifenthrin on stream ecosystems are largely unknown. To investigate such effects, a manipulative experiment was conducted in stream mesocosms that were colonized by aquatic insect communities and exposed to bifenthrin-contaminated sediment; implications for natural streams were...Rogers, Holly; Schmidt, Travis S.; Dabney, Brittanie L.; Hladik, Michelle; Mahler, Barbara J.; Van Metre, Peter C.
Isotopic insights into biological regulation of zinc in contaminated systems
Aquatic organisms use a variety of biogeochemical reactions to regulate essential and non-essential trace metals. Many of these mechanisms can lead to isotopic fractionation, thus measurement of metal isotopes may yield insights into the processes by which organisms respond to metal exposure. We illustrate these concepts with two case studies, one...Wanty, Richard B.; Balistrieri, Laurie S.; Wesner, Jeff S.; Walters, David; Schmidt, Travis S.; Podda, Francesca; De Giudici, G.; Stricker, Craig A.; Kraus, Johanna M.; Lattanzi, Pierfranco; Wolf, Ruth E.; Cidu, R.
Expanding metal mixture toxicity models to natural stream and lake invertebrate communities
A modeling approach that was used to predict the toxicity of dissolved single and multiple metals to trout is extended to stream benthic macroinvertebrates, freshwater zooplankton, and Daphnia magna. The approach predicts the accumulation of toxicants (H, Al, Cd, Cu, Ni, Pb, and Zn) in organisms using 3 equilibrium accumulation models that define...Balistrieri, Laurie S.; Mebane, Christopher A.; Schmidt, Travis S.; Keller, William (Bill)
Soil disturbance as a driver of increased stream salinity in a semiarid watershed undergoing energy development
Salinization is a global threat to the quality of streams and rivers, but it can have many causes. Oil and gas development were investigated as one of several potential causes of changes in the salinity of Muddy Creek, which drains 2470 km2 of mostly public land in Wyoming, U.S.A. Stream discharge and salinity vary with seasonal snowmelt and...Bern, Carleton R.; Clark, Melanie L.; Schmidt, Travis S.; Holloway, JoAnn M.; Mcdougal, Robert
Metamorphosis alters contaminants and chemical tracers in insects: implications for food webs
Insects are integral to most freshwater and terrestrial food webs, but due to their accumulation of environmental pollutants they are also contaminant vectors that threaten reproduction, development, and survival of consumers. Metamorphosis from larvae to adult can cause large chemical changes in insects, altering contaminant concentrations and...Kraus, Johanna M.; Walters, David M.; Wesner, Jeff S.; Stricker, Craig A.; Schmidt, Travis S.; Zuellig, Robert E.
Metamorphosis enhances the effects of metal exposure on the mayfly, Centroptilum triangulifer
The response of larval aquatic insects to stressors such as metals is used to assess the ecological condition of streams worldwide. However, nearly all larval insects metamorphose from aquatic larvae to winged adults, and recent surveys indicate that adults may be a more sensitive indicator of stream metal toxicity than larvae. One hypothesis to...Wesner, Jeff S.; Kraus, Johanna M.; Schmidt, Travis S.; Walters, David M.; Clements, William H.
Cross-ecosystem impacts of stream pollution reduce resource and contaminant flux to riparian food webs
The effects of aquatic contaminants are propagated across ecosystem boundaries by aquatic insects that export resources and contaminants to terrestrial food webs; however, the mechanisms driving these effects are poorly understood. We examined how emergence, contaminant concentration, and total contaminant flux by adult aquatic insects changed...Kraus, Johanna M.; Schmidt, Travis S.; Walters, David; Wanty, Richard B.; Zuellig, Robert E.; Wolf, Ruth E.
Environmental Ratios of Cadmium and Zinc are less Toxic to Aquatic Insects than Expected
Bifenthrin combats pests, but may harm aquatic ecosystems