Diatom identification guide & ecological resource

for water resource managers, ecologists, taxonomists, analysts, systematists, students, and the public.

We aim to provide everyone with accurate information about diatoms of the United States.

Expert contributors are submitting text and images for freshwater genera and North American species, including taxonomic and ecological information.

Diatom "visual guides" are included for all taxa.  The guides illustrate key traits that distinguish a taxon (examples to the right). For many species, environmental response plots and geographic distribution maps are also included.

Our editorial review board is prioritizing taxa for treatment in species pages and ensuring the scientific merit of each submission.

See any issues with content or functionality? If so,  please let us know

Achnanthidium pyrenaicum


155 Completed
21 Underway
834 Completed
188 Underway
1022 TOTAL

Getting Started

About this website

What are diatoms?

Identify your taxa

Special News

26 June, 2015

Editorial Review Guidelines

25 March, 2011

Information for contributors


06 April, 2017

Summer Field Courses in Iowa

01 February, 2017

The Gomphonema Round Up Taxon Workshop

More news...


Ecology and Systematics of Diatoms course, 2012

Atmospheric deposition of nitrogen and its effects on diatoms

From a playful summer camp…

More projects...