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Mr. Tengwall is a visiting professor in the Department of Business & Economics, where he engages students on a range of topics including Management & Leadership, Business Models & Growth Strategy, Sales & Marketing, and Supply Chain/Operations Management. He also serves on the Boards of two companies and provides management consulting services to a range of businesses.

Previously, Mr. Tengwall had a 12-year career with the Marmon Group, a Berkshire Hathaway Company. During this time he was President of EcoWater Systems LLC (2019 – 2024), a leading North American manufacturer and marketer of residential and light commercial water softening and filtration systems. Prior to that, he was president of Marmon Food & Beverage Solutions Group (2013 – 2019), which was comprised of two different businesses, Marmon Link and Marmon Renew. Marmon Link (previous dba 3Wire Group Inc) is a provider of parts, training and service for foodservice and beverage dispensing equipment. Marmon Renew is a re-manufacturer of commercial beverage dispensing and related foodservice equipment.

Prior to his executive leadership roles with Marmon/Berkshire Hathaway, he had a 17-year career with Ecolab (NYSE: ECL). There he held several progressively more responsible leadership roles in the Institutional and Food & Beverage operating divisions. He led the marketing function for both business segments and engaged in multiple acquisitions as part of the overall business growth strategy.

Mr. Tengwall began his career as a microbiologist in the Sterilization Technology & Process Control Validation group at The Upjohn Company (now Pfizer). He then pivoted into marketing and business development roles with IMI Cornelius Inc., a subsidiary (at the time) of IMI plc.

John C. Volin, PhD serves as the 18th President of Gustavus. 

Following a postdoctoral fellowship in plant physiological ecology at the University of Wisconsin-Madison, Volin accepted a faculty position at Florida Atlantic University, where he rose to the rank of full professor in the Department of Biological Sciences and served as the director of the Environmental Sciences graduate program. Volin joined the University of Connecticut in 2007 to head the Department of Natural Resources and the Environment, advancing to serve as Vice Provost of Academic Affairs. From 2020-2025, Volin served as the Executive Vice President for Academic Affairs and Provost at the University of Maine, where his portfolio included oversight of more than 1,000 faculty and staff and a budget of over $250 million. Volin is recognized as a national leader in using evidence-based practices to support holistic student wellbeing. He serves on the Executive Committee of the LearningWell Coalition and is a co-founder and senior advisor of LearningWell magazine.

Born and raised in Sioux Falls, South Dakota, Volin holds a BS in botany and biology and an MS in agronomy from the South Dakota State University, and a PhD in forestry from the University of Wisconsin-Madison. Volin and his wife, Valeria, have five children and six grandchildren.

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Jon Grinnell is the Francis Morey Uhler Chair in Biology. He spent his youth roaming the hills of coastal California watching the hawks and admiring alligator lizards and rattlesnakes. From the time of his first borrowed binoculars he has been fascinated with wild creatures and places, and now is excited to share those with students. 

As an undergraduate he worked with the last wild California Condors before they were taken into captive breeding programs, and as a graduate student he studied the social and communication behavior of African lions in Tanzania. For years, he worked on lions in South Africa before transitioning to American bison in South Dakota. In each of these projects he eagerly involved research students, as one of his great loves is taking students out into the field to get hands-on experience with animals and ecosystems. 

Recently his attention has shifted to the plight of shallow marine habitats and regularly takes students to study the Mesoamerican coral reef in Belize. Jon feels privileged to have the chance to teach animal behavior, aquatic biology, vertebrate zoology, and other field-based courses at Gustavus, as well as the many travel courses he has led throughout South and Central America and the Caribbean.

Jon is an avid cyclist, scuba diver, hiker, animal watcher, and bow hunter.