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Awarded to Sarah Guberman for the Usenko Lab's work on pesticides.

National Science Fellowship Award

Center for Reservoir and Aquatic Research Systems

American Chemical Society

Society of Environmental Toxicology and Chemistry

Chemistry Steering Committed for SETAC

Chemistry Advisor Group for SETAC

University Sustainability Committee

Phi Lambda Upsilon Honor Chemical Society

Temporal variation in groundwater quality in the Permian Basin of Texas, a region of increasing unconventional oil and gas development

Spatial and Temporal Distribution of Current-Use Pesticides in Atmospheric Particulate Matter in Houston, Texas

Selective pressurized liquid extraction as a sample-preparation technique for persistent organic pollutants and contaminants of emerging concern

Evolved resistance to PCB- and PAH-induced cardiac teratogenesis, and reduced CYP1A activity in Gulf killifish (Fundulus grandis) populations from the Houston Ship Channel, Texas

Relative Importance of the Humic and Fulvic Fractions of Natural Organic Matter in the Aggregation and Deposition of Silver Nanoparticles

Whale Earwax Research Exhibit

Dr. Sascha Usenko's, associate professor of environmental science, current research on whale earwax builds on his Ph.D. research, where he gained expertise reconstructing organic contaminant profiles in sediment cores. He obtained a bachelor's degree in environmental science and a doctorate degree in analytical chemistry from Oregon State University.

Using a wide range of analytical techniques such as pressurized liquid extraction and GC/MS, he reconstructed more than 280 contaminant profiles for 14 national parks throughout the western United States. Now using similar analytical techniques, his laboratory has developed the ability to reconstruct organic contaminant and mercury profiles for an individual whale using its laminated earwax plug.

As an analytical and environmental chemist, he was fascinated to learn that many whale species accumulate layers of wax in their ear canal forming an earplug over their entire lifespan, which is sealed from the external environment.

"I was elated to then learn that scientists in the past have used this waxy matrix as an aging tool, similarly to counting tree rings," Usenko said. "Then the question arose, could earwax plugs chronologically archive fat-soluble chemicals, such as man-made pollutants?"

Over the past two years, Usenko's laboratory has been working on developing the analytical methods capable of answering that very question.

"The answer is an emphatic yes! I am happy to report we now have the analytical methods capable of measuring organic contaminants, mercury, and now hormones in whale earwax," Usenko said. "Utilizing these methods, we can now reconstruct lifetime chemical profiles (i.e. from birth to death) for an individual whale for the first time."

Aquatic Ecology

Environmental Forensic Chemistry

Anthropogenic Contaminants 

Baylor - The Usenko Laboratory

University of Houston Researchers Confirm Ozone & Particulates Are Issues In San Antonio Air

Green Communities event in Waco brings climate risks, solutions into focus

Rebecca Sheesley and Sascha Usenko

Baylor Researchers Earn Department of Energy Grant to Study Impact of Urban Pollution on Thunderstorm Activity

Sascha Usenko, Ph.D., environmental science

baylor-professors-use-whale-earwax-to-reconstruct-whale-stress-levels-spanning-more-than-a-century

Professor of Environmental Science. Director, Environmental Science Graduate Program

In a follow-up to their groundbreaking study, Baylor researchers were able to reconstruct baleen whales’ lifetime stress response to whaling and other manmade and environmental factors spanning nearly 150 years.

Using a technique they pioneered six years ago, Stephen J. Trumble, Ph.D., associate professor of biology, and Sascha Usenko, Ph.D., associate professor of environmental science, both in Baylor University’s College of Arts & Sciences, analyzed earplug laminae, a growth layer representing six months found in whale earwax, as part of their recent study published in Nature Communications this month.

Using earplugs taken from fin, humpback and blue whales originating in the Pacific and Atlantic Oceans from 1870 to 2016, Trumble and Usenko were able to determine the whales’ cortisol levels, a stress-response hormone, to industrial whaling, World War II wartime activities and sea-surface temperature.

“This is the first-ever study to quantify temporal stress patterns in baleen whales,” Trumble said. “While the generated stress profile spans nearly 150 years, we show that these whales experienced survivor stress, meaning the exposure to the indirect effects of whaling, including ship noise, ship proximity and constant harassment, results in elevated stress hormones in whales spanning vast distances.”

Whaling had a significant impact on whales’ cortisol levels. During the 1960s when whaling was at its peak with 150,000 whales harvested, cortisol peaked to a maximum and was the highest average in whales in the 20th century, according to the study’s findings.

 Second in a three-part exclusive online look at content from the Natural History Museum's Whales: Beneath the surface exhibition featuring Dr. Stephen J. Trumble and Dr. Sascha Usenko. During World War II when whaling declined, whales still showed an increase in cortisol levels. Trumble and Usenko suggest the impact of the theater of war.

“The stressors associated with activities specific to WWII may supplant the stressors associated with industrial whaling for baleen whales,” Usenko said. “We surmised that wartime activities such as under water detonation, naval battles including ships, planes and submarines, as well as increased vessel numbers, contributed to increase cortisol concentrations during this period of reduced whaling.”

When whaling moratoriums were introduced in the mid-1970s, whaling decreased as well as cortisol levels—reaching their lowest concentrations.

“From the 1970s through the 2010s whaling counts were reportedly zero in the Northern Hemisphere, but mean cortisol levels steadily increased, with recent peaks reaching near the maximum levels observed before whaling moratoriums,” Usenko said.

The impact of stress on whales could have larger implications for baleen whales, which are “considered sentinels of their environment and indicators of anthropogenic or manmade stressors,” Usenko said.

“This study shows that anthropogenic stressors results in a physiological response in large whales. These chronic stressors may impact life history events such as reproductive parameters,” Trumble said. “Lastly, human-based stressors such as warming sea surface temperatures may also result in elevated stress in these whales.”

The research pair has expanded the number of museums they partner with and currently have more than 100 additional earplugs to process. Earplugs were provided through a collaboration between the investigators and the Smithsonian Museum of Natural History and the Museum of Natural History London. ABOUT BAYLOR UNIVERSITY Baylor University is a private Christian University and a nationally ranked research institution, characterized as having “high research activity” by the Carnegie Foundation for the Advancement of Teaching. The University provides a vibrant campus community for approximately 15,000 students by blending interdisciplinary research with an international reputation for educational excellence and a faculty commitment to teaching and scholarship. Chartered in 1845 by the Republic of Texas through the efforts of Baptist pioneers, Baylor is the oldest continually operating University in Texas. Located in Waco, Baylor welcomes students from all 50 states and more than 80 countries to study a broad range of degrees among its 11 nationally recognized academic divisions. Baylor sponsors 19 varsity athletic teams and is a founding member of the Big 12 Conference.

ABOUT BAYLOR COLLEGE OF ARTS & SCIENCES The College of Arts & Sciences is Baylor University's oldest and largest academic division, consisting of 26 academic departments and 13 academic centers and institutes. The more than 5,000 courses taught in the College span topics from art and theatre to religion, philosophy, sociology and the natural sciences. Faculty conduct research around the world, and research on the undergraduate and graduate level is prevalent throughout all disciplines.



Baylor Professors Use Whale Earwax to Reconstruct Whale Stress Levels Spanning More Than a Century

Baylor University (Texas) researchers Stephen Trumble, Ph.D., assistant professor biology, and Sascha Usenko, Ph.D., assistant professor of environmental science, have discovered a novel technique for using whale ear wax to reconstruct whales' lifetime exposure to chemicals and environmental pollutants, as well as time-specific biological information about the endangered mammals. Using this new, previously unattainable data, the professors are able to assess the human impact on individual whales and multiple generations, as well as provide a better understanding of the effect on marine ecosystems. Their research findings appear online in the Sept. 16, 2013, issue of the Proceedings of the National Academy of Sciences of the United States of America.

Baylor Professors Study Whale Earwax to Uncover Ocean Contaminants

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