Holt is a freshwater ecologist who studies the biology of algae and their roles in aquatic ecosystems. He and his students conduct research on the algal communities of local areas such as Penns Creek and the 体育买球官网 River, as well as those in Yaroslavl, Russia. He is a member of the 体育买球官网 River Heartland Coalition for Environmental Studies, also known as “The River Group.” He and his students present their work at regional and national conferences and in journals such as theJournal of Freshwater Ecologyand theJournal of the Pennsylvania Academy of Science.

Holt’s teaching includes Systematic Biology, Aquatic Ecology, and Thought and the Natural Sciences for Honors Program students. In addition, he is the director of the Ecology Program.

He is the director of Saturday Science, a hands-on science experience for local elementary students and teachers in training. The program has been funded by Pennsylvania Space Grant since 1993. A collection of essays that he wrote as part of his duties in Saturday Science has been published asPaths of Science, which is now in its second edition. Saturday Science also provides scholarships for students to study with him in Yaroslavl, Russia, for four to five weeks during the summer.