Ruth Patrick (born 1907) has pioneered techniques for studying the biodiversity of freshwater ecosystems over a career that spans sixty years. Her studies of microscopic species of algae, called diatoms, in rivers around the world have provided methods for monitoring water pollution and understanding its effects.

Federal programs to monitor the status of freshwater rely on Ruth Patrick's method of growing diatoms on glass slides. Her studies of the impact of trace elements and heavy metals on freshwater ecosystems have demonstrated how to maintain a desired balance of different forms of algae. For example, she showed that addition of small amounts of manganese prevents the overgrowth of blue-green algae and permits diatoms to proliferate.

Patrick received the prestigious Tyler Ecology Award in 1975, and serves on numerous governmental advisory committees. She advanced the field of limnology, the study of freshwater biology, and in the late 1940s established the Department of...