(707) 431-5100
(707) 431-5100

Denise Tonn

Science Teacher
Ext. 144
“I’ve loved almost every minute of my 8 years at Rio. I love the opportunities to take students to the river and to the Mendocino coast. I love my big, spacious classroom. I love chicken nugget and buffalo cauliflower day at the cafe. Most of all, I love the relationships I’ve been able to form with students and staff. We have the best people in the world, right here,” says Denise Tonn.


Denise Tonn started at Rio in 2013 and teaches biology, chemistry, and anatomy & physiology. During the school year, Mrs. Tonn takes students on several STEM-oriented outings around the Bay Area including the UC Davis Research Lab in Bodega Bay. Mrs. Tonn spent much of her early career researching fisheries and waterways in the Northwest. Previous to Rio, Mrs. Tonn has taught in Arizona, Thailand, and Guyana.

In her spare time, Mrs. Tonn enjoys spending time with her family and dog and exploring the outdoors. She loves learning new things together with her students and her favorite aspect of teaching is learning about students’ hidden talents.


  • B. S. in Biology, M.S in Biology emphasis on fisheries research