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

Sellaphora californica


155 Completed
23 Underway
840 Completed
203 Underway
1043 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, 2013

Ecology and Systematics of Diatoms course, 2012

Renovation and computerization of ANSP Diatom Herbarium

More projects...