The diatom Cylindrotheca gracilis (Breb. ex Kutz) Grun., considered by some as a "Brackish water" species, was found as a massive growth in isolated pools along Dugout Creek, Dickinson County, Iowa. Chemical analyses show the water to be high in S04, Mg., Ca., and low in Cl ions. Comparative data from other waters in the United States containing this species shows similar pattern of high conductivity suggesting that factors other than chlorides might be more critical for growth. United States distribution for this diatom includes: Maryland (brackish water), Ohio (fresh water) and Iowa (fresh water).
Proceedings of the Iowa Academy of Science
©1968 Iowa Academy of Science, Inc.
Christensen, C. L. and Reimer, C. W.
"Notes on the Diatom Cylindrotheca gracilis (Breh. ex Kutz) Grun: Its Ecology and Distribution,"
Proceedings of the Iowa Academy of Science, 75(1), 36-41.
Available at: https://scholarworks.uni.edu/pias/vol75/iss1/9