Spirit Lake is the largest lake in Iowa. The East Okoboji chain is the longest lake in Iowa. The algal flora is outstanding, and the station has attracted students of the algae for many years. The local aquatic and terrestrial flora have been well studied, and the station maintains a herbarium of the local flora as well as a diagnostic collection of diatoms. The fauna is representative of the Upper Midwest.
Small mammals are numerous.
Several species of amphibians and reptiles occur in large numbers. Approximately 50 species of fish inhabit the rivers, ponds, and lakes of the region. Certain species spawn during June and July and thus offer the opportunity to study breeding behavior, nesting and care of young, and embryonic development. A large number of birds reside and nest locally. Water and shore birds are abundant, as are passerine birds that inhabit the marshes and prairies.